Document:

PARTICIPATION AGREEMENT
                                     between

                                  GOM SHELF LLC
                            BY APACHE CORPORATION AS
                                 MANAGING MEMBER

                                       and

                                RIDGEWOOD ENERGY
                                   CORPORATION

                          SALTAMONTES PROFUNDO PROSPECT
                            OCS-G 00839, 01497, 01498

                      BLOCKS 94, 95 and 96, West Delta Area

                                 GULF OF MEXICO

<PAGE>

Participation Agreement dated March 28, 2005
Between GOM Shelf LLC and Ridgewood Energy Corporation
Page 2

                             PARTICIPATION AGREEMENT
                  SALTAMONTES PROFUNDO PROSPECT BLOCKS 94, 95,
                               96, WEST DELTA AREA
                                 GULF OF MEXICO

This Participation Agreement ("Agreement") is made and entered into effective as
of the 28th day of March, 2005 (the "Effective Date"), by and between GOM Shelf
LLC BY APACHE CORPORATION AS MANAGING MEMBER ("GOM"), a Delaware corporation,
and Ridgewood Energy Corporation ("Ridgewood"), a Delaware corporation sometimes
hereinafter referred to collectively as the "Parties" and individually as
"Party."

                                   WITNESSETH:

WHEREAS, the Parties have entered into the Ridgewood/GOM Deep Shelf Initiative
(the "Initiative") dated March 24, 2005, that provides, among other things, for
the execution of this Agreement in the event Ridgewood elects to participate in
a Prospect, as hereinafter defined, presented by GOM pursuant to such
Initiative; and

WHEREAS, GOM is the owner of a portion of Federal Leases OCS-G 00839, OCS-G
01497, and OCS-G 01498, covering all of Blocks 94, 95 and 96, West Delta Area,
OCS Leasing Map No. 8, containing approximately 13,665.07 acres and further
limited to cover that area described on Exhibit "A" and outlined in red on the
plat attached hereto as Exhibit "A-1" containing approximately 7,134 acres, more
or less ("the Lease"); and

WHEREAS, the Parties believe the Prospect, as hereinafter defined and known as
the Saltamontes Profundo Prospect, is wholly contained within the Lease; and

WHEREAS, Ridgewood has elected pursuant to the Initiative and subject to the
terms and conditions contained herein to acquire a portion of the Lease from GOM
covering the Prospect Area, as hereinafter defined and described on Exhibit "A"
hereto and thereafter participate in certain operations on the Prospect Area, as
hereinafter defined, and assume all rights, duties, interests and obligations
arising thereunder.

NOW, THEREFORE, in consideration of the mutual covenants and agreements herein
contained, the Parties agree as follows:

<PAGE>

Participation Agreement dated March 28, 2005
Between GOM Shelf' LLC and Ridgewood Energy Corporation
Page 3

                                    ARTICLE 1
                                   Definitions

Affiliate means a legal entity which Controls, or is Controlled by, or which is
Controlled by an entity which Controls, a Party.

Casing Point means that point in time after the contract depth has been reached
in drilling the Initial Well, as hereinafter defined, said well has been fully
evaluated by the running of such logs and conducting such other open-hole
evaluation as the Parties hereto may deem appropriate, and after the results of
said logs and open-hole evaluation are known and delivered to the Parties
hereto, and a decision is made to attempt to complete or deepen the Initial Well
or to plug and abandon the well. However, should the decision be to plug and
abandon the well, it shall be deemed not to have reached "Casing Point" until
all operations are complete with respect to the plugging and abandoning of the
Initial Well.

Control means the ownership directly or indirectly of fifty percent (50%) or
more of the voting rights in a legal entity. "Controls", "Controlled by" and
other derivatives shall be construed accordingly.

Authorization for Expenditure (AFE) means an authorization to expend funds that
estimates costs to be incurred for an Operation pursuant to the Operating
Agreement as referenced herein.

Conditions Precedent has the meaning ascribed to it in Article 3.

Evaluation Data means geological or geophysical data and other data and
information relating to a Prospect including, without limitation, all relevant
geological and geophysical interpretations and information, including reports,
interpretations, models and maps and all specialty processing and analysis of
seismic data and may also include commercial, contractual and financial
information.

Force Majeure means an act of God, strike, lockout, or other industrial
disturbance, act of the public enemy, war, blockade, public riot, lightning,
fire, storm, flood, or other act of nature, explosion, governmental action or
restraint, unavailability of equipment, and any other cause, whether of the kind
specifically enumerated above or otherwise, that is not reasonably within the
control of the Party claiming suspension. It is, however, expressly agreed that
promptness of performance is of the essence under this Agreement and that every
reasonable effort will be made by the Parties to avoid delay or suspension of
any work or acts to be performed under this Agreement. The requirement that the
Force Majeure be remedied with all reasonable dispatch shall not require a Party
to settle strikes or other labor difficulties.

Initiative has the meaning ascribed to it in the Preamble.

<PAGE>

Participation Agreement dated March 28, 2005
Between GOM Shelf' LLC and Ridgewood Energy Corporation
Page 4

Lease means an instrument issued by the United States of America by the Regional
Director, Gulf of Mexico OCS Region, Minerals Management Service ("MMS"),
granting certain rights including but not limited to rights to explore for and
produce Crude Oil and Natural Gas, as defined in the Initiative.

Net Revenue Interest means the, Working Interest, less applicable burdens,
proportionately reduced.

Operating Agreement has the meaning ascribed to it in Article 5.

Objective Depth has the meaning ascribed to it in Article 6,

Preferential Right to Purchase means obligations with respect to a Lease or its
related agreements that exist at the Effective Date and that may include
requirements to satisfy obligations, including, but not limited to, the
obligation to offer the terms and provisions of this Agreement or the Initiative
to a third party holding contractual rights applicable to a Lease,

Prospect means, in general, a geologic structural, stratigraphic trap or
combination thereof that is believed to have the potential for accumulations of
hydrocarbons, as defined in the Initiative, in commercial quantities and that
lies at a depth greater than or equal to fifteen thousand feet (15,000) subsea
and whose associated Lease may obtain royalty relief pursuant to 30 CFR 203 as
amended or a similar royalty relief provision contained in the Lease itself.
Prospect means, specifically as it relates to this Agreement, the Saltamontes
Profundo aspect.

Prospect Area means the geographic area encompassing the Prospect and any depth
limitation applicable thereto, as fully described on Exhibit "A" hereto, and
which shall be identified by legal description appropriate for recording
purposes with the MMS.

Working Interest means the undivided interest of a Party, expressed as a
percentage of the total interests of all Parties, in the rights and obligations
derived from this Agreement and also means the undivided interest of a party,
expressed as a percentage of the total interests of all Parties, in the rights
and obligations in and to a Lease.

                                    ARTICLE 2
                       Assignment and Assumption of Rights

2.1 In exchange for the consideration stated herein, (SOM. hereby agrees to
assign and transfer to Ridgewood, concurrent with the execution of this
Agreement, and Ridgewood hereby agrees to accept, an assignment of an undivided
fifty three and one-third percent (53,33333%) of

<PAGE>

Participation Agreement dated March 28, 2005
Between GOM Shelf LLC and Ridgewood Energy Corporation
Page 5

GOM's undivided thirty seven and one-half percent (37.50000%) Working Interest
in the Lease insofar as it encompasses the Prospect Area, being a net undivided
Working Interest of twenty percent (20.00000%), with a corresponding Net Revenue
Interest of sixteen and two-thirds percent (16.66667%).

2.2 The Parties shall execute and deliver an assignment evidencing the above in
the form attached as Exhibit "F" to the Initiative. Following such assignment,
the net Working Interests in the Lease or portion thereof shall be:

       GOM:                                                     17.50%

       Ridgewood:                                               20.00%

       BP America Production Company:                           37.50%

       Chevron/Texaco Exploration & Production, Inc:            25.00%

                      Total                                    100.00%

                                    ARTICLE 3
                       Conditions Precedent to Assignment

3.1 The validity of the assignment hereunder is subject to the satisfaction or
waiver of each of the following conditions, collectively called "Conditions
Precedent", that:

     A.   GOM obtains a waiver or other evidence in writing of the expiration or
          non exercise of any Preferential Right to Purchase;

     B.   The Parties obtain any necessary approvals from the U.S. Government or
          any appropriate division thereof to the assignment in writing, the
          cost of which shall be borne by Ridgewood; and

     C.   The Parties obtain any other required third party consents for the
          transfer of the Working Interest proposed to be transferred hereunder
          in writing.

3.2 As soon as is reasonably practicable after execution of this Agreement, each
Party shall use commercially reasonable efforts to execute all documents, and do
and procure to be done all such acts and things as are reasonably within its
power to attempt to secure required consents or waivers in an effort to satisfy
the Conditions Precedent. Notwithstanding the above, in the event such
Conditions Precedent are not satisfied despite the Parties' commercial
reasonable efforts to overcome the same, then this Agreement shall terminate and
neither Party shall have any further obligation to the other Party with respect
to this Agreement.

<PAGE>

Participation Agreement dated March 28, 2005
Between GOM Shelf LLC and Ridgewood Energy Corporation
Page 6

                             ARTICLE 4 Consideration

4.1 In consideration for receiving the assignment of Working Interest hereunder,
Ridgewood agrees to pay one hundred sixty percent (160%) of its Working Interest
share of all costs and expenses associated with the drilling of the Initial Well
on the Saltamontes Profundo Prospect, up to Casing Point, including plugging and
abandonment costs in the event a completion attempt is not made in the Initial
Well.

4.2 Notwithstanding anything to the contrary herein, if costs associated with
the drilling of the Initial Well reach one hundred twenty percent (120%) of the
AFE gross dry hole cost, then Ridgewood shall thereafter bear only its Working
Interest share of remaining costs for the Initial Well as detailed in the AFE
attached hereto as Exhibit "B".

                                    ARTICLE 5
                               Operating Agreement

5.1 Subject to Article 5.2 below, concurrent with the execution of this
Agreement, the Parties shall execute an offshore operating agreement in
substantially the same form attached as Exhibit "C" to the Initiative
("Operating Agreement") and which shall name GOM as operator. All operations
conducted pursuant to this Agreement shall be governed by the terms and
provisions of said Operating Agreement.

5.2 In the event there is an operating agreement in effect covering the Prospect
Area on the Effective Date, Ridgewood hereby ratifies, confirms, and accepts the
terms of such existing operating agreement and assumes the obligations thereto
with respect to the Working Interest assigned to Ridgewood and agrees to abide
by the terms of such operating agreement to the extent of its Working Interest
insofar and only insofar as said operating agreement is applicable to the
Prospect Area.

                                    ARTICLE 6
                                  Initial Well

6.1 The "Initial Well" will be drilled from a surface location of X= 2,481,386
and Y= 92,725 to a bottomhole location of X=2,481,386 and Y= 90,916, to a depth
sufficient to test the PD Sand Amplitude or to a depth of 18,350 feet MD and
17,900 feet TVD, whichever is lesser ("Objective Depth"), in accordance with the
AFE attached hereto as Exhibit "B".

6.2 Subject to permitting, rig availability and events of Force Majeure, GOM
shall use all commercially reasonable efforts to commence operations on the
Initial Well within one hundred fifty (150) days of the Effective Date hereof.

<PAGE>

Participation Agreement dated March 28, 2005
Between GOM Shelf LLC and Ridgewood Energy Corporation
Page 7

6.3 In the event operations for the Initial Well are not commenced by GOM or
other third party, if GOM is not the operator, within one hundred fifty (150)
days of the Effective Date hereof, other than for reasons attributable to
permitting, rig availability, or Force Majeure, then Ridgewood may, within
thirty (30) days following such one hundred fifty (150) day period, elect to
terminate this Agreement and Ridgewood hereby agrees, in the event of such
termination, to reassign to GOM the Working Interest assigned to Ridgewood
pursuant to this Agreement; provided, however, such assignment to GOM shall be
in substantially the same form of assignment as GOM's assignment to Ridgewood
and the Working Interest reassigned to GOM shall be free and clear of all liens,
claims, encumbrances and burdens created by, through or under Ridgewood.

6.4 In the event operations for the Initial Well are not commenced within three
hundred (300) days of the Effective Date hereof, other than for reasons
attributable to permitting, rig availability, or Force Majure, and the Agreement
has not been terminated per Article 6.3 above, then GOM, at its sole discretion,
may request a reassignment of the Working Interest assigned to Ridgewood
pursuant to this Agreement and Ridgewood hereby agrees under such circumstances
to promptly execute such reassignment. Such assignment to GOM shall be in
substantially the same form of assignment as GOM's assignment to Ridgewood and
the Working Interest reassigned to GOM shall be free and clear of all liens,
claims, encumbrances and burdens created by, through or under Ridgewood.

6.5 GOM shall provide Ridgewood with copies of all well information from the
Initial Well and any other well as indicated and required under the Operating
Agreement or any operating agreement in existence and covering the Prospect
which Ridgewood becomes a Party to in accordance with Article 5.2.

6.6 In the event the Initial Well does not reach the Objective Depth because of
mechanical difficulties or Gulf Coast Conditions (i.e. rock salt, heaving shale,
excessive water flow, depleted sands, excessive pressure, base or other
impenetrable matter) which prevent the operator from drilling the Initial Well
to Objective Depth, the Parties hereto may cause the drilling of a substitute
well on or before the earlier of the date occurring (a) one hundred twenty (120)
days after the release of the drilling rig for the Initial Well or (b) after the
lapse of a one hundred twenty (120) day period without the drilling of any
additional footage in the Initial Well (or plugging back in the case of a
proposed sidetrack). As between the Parties hereto, any substitute well shall
require the concurrence of one (1) or more of said Parties with at least fifty
percent (50%) Working Interest, proportionately reduced, and shall be drilled to
target the same objective as the Initial Test Well. If the Parties elect to
drill a substitute well, then the consideration to be paid in accordance with
Article 4.1 hereof shall be carried over to the substitute well, but the
limitation provided in Article 4.2 shall remain in effect.

<PAGE>

Participation Agreement dated March 28, 2005
Between GOM Shelf LLC and Ridgewood Energy Corporation
Page 8

                                    ARTICLE 7
                         Representations and Warranties

7.1 Ridgewood makes the following representations and warranties to GOM as of
the Effective Date:

     A.   There are no material claims, demands, actions, suits, governmental
          inquiries, or proceedings pending, or to Ridgewood's knowledge,
          threatened, against Ridgewood which would have an adverse effect upon
          the consummation of the transactions contemplated by this Agreement.

     B.   Ridgewood has sufficient cash, available lines of credit or other
          sources of immediately available funds to enable it to fulfill all of
          its obligations under this Agreement.

     C.   Each Party represents and warrants that it is duly qualified with the
          MMS to do business in the Outer Continental Shelf.

     D.   Ridgewood has the technical capability, personnel and resources to
          fulfill its obligations under this Agreement.

7.2 The Parties make the following representations and warranties to each other
as of the Effective Date:

     A.   Such Party is duly organized and validly existing under the laws of
          the state where it is organized;

     B.   Such Party has all requisite corporate power and authority to enter
          into this Agreement, to perform its obligations hereunder, and to
          consummate the transactions contemplated hereby; and

     C.   This Agreement has been duly executed and delivered by each Party and
          constitutes a legal, valid and binding obligation of each Party,
          enforceable against each Party in accordance with its terms.

7.3  GOM MAKES NO REPRESENTATION OR WARRANTIES, EXPRESS OR IMPLIED, AS TO THE
     QUALITY, ACCURACY AND COMPLETENESS OF THE INFORMATION INCLUDED IN A
     PROSPECT PRESENTATION OR ANY OTHER EVALUATION DATA FURNISHED BY GOM TO
     RIDGEWOOD PURSUANT TO THIS AGREEMENT AND RIDGEWOOD EXPRESSLY ACKNOWLEDGES
     THE INHERENT RISK OF ERROR IN THE ACQUISITION, PROCESSING AND
     INTERPRETATION OF GEOLOGICAL AND GEOPHYSICAL DATA. GOM, ITS AFFILIATED
     COMPANIES, THEIR

<PAGE>

Participation Agreement dated March 28, 2005
Between GOM She4'LLC and Ridgewood Energy Corporation
Page 9

     OFFICERS, DIRECTORS AND EMPLOYEES SHALL HAVE NO LIABILITY WHATSOEVER WITH
     RESPECT TO THE USE OF OR RELIANCE UPON THE EVALUATION DATA BY RIDGEWOOD OR
     ITS REPRESENTATIVE.

                                    ARTICLE 8
                                 Confidentiality

The Evaluation Data covering the Prospect Area will be subject to the terms and
provisions of the Confidentiality Agreement dated January 12, 2005, signed in
accordance with the Initiative.

                                    ARTICLE 9
                                  Governing Law

The substantive law of the State of Texas, exclusive of any conflicts of laws
principles that could require the application of any other law, shall govern
this Agreement for all purposes, including the resolution of disputes between or
among Parties.

                                   ARTICLE 10
                                     Notices

Notice by one (1) Party to another under this Agreement shall be in writing and
shall be delivered by hand, registered mail, overnight mail, or sent by
facsimile to the respective Party at the address or facsimile number shown
below, or such other address or facsimile number as a Party may designate by
notice to the other Party, and shall be deemed to be delivered only when
received by the Party to whom such notice is directed:

 GOM Shelf LLC                                  RIDGEWOOD ENERGY
 2000 Post Oak Boulevard, Suite 100             11700 Old Katy Rd., Suite 280
 Houston, Texas 77056-4400                      Houston, Texas 77079
 ATTN: Land Manager-Gulf Coast Region           ATTN: Mr. W. Greg Tabor
 Facsimile:      713-296-7024                   Facsimile:      281-293-7705

                                   ARTICLE 11
                              Public Announcements

Except as required by applicable law, rule or stock exchange regulation or a
third party agreement as referenced above, neither Party nor their Affiliates
will make any public comment, statement, or communication with respect to the
existence of this Agreement or any ongoing negotiations between the Parties
without the prior consent of the other Party. If a Party is

<PAGE>

Participation Agreement dated March 28, 2005
Between GOM Shelf LLC and Ridgewood Energy Corporation
Page 10

required by law, rule or stock exchange requirement to make any such disclosure,
it will provide advance written notice to the other Party specifying the content
of the proposed disclosure, the reasons that such disclosure is required, and
the time and place that the disclosure will be made and shall limit any
disclosure only to such information which the disclosing Party reasonable
believes upon advice of counsel, is required to be disclosed. Notwithstanding
anything to the contrary above, Ridgewood or its designated subsidiary, will not
be restricted or precluded from providing certain non-confidential information
about the program or a Prospect(s) in any marketing brochure, drilling fund
prospectus or related company website.

                                   ARTICLE 12
                                  Force Majeure

  If a Party is unable, wholly or in part by Force Majeure, to carry out its
  obligations under this Agreement, other than the obligation to make money
  payments, that Party shall give the other Party prompt written notice of the
  Force Majeure with full particulars about it. Thereupon, the obligations of
  the Party giving the notice, so far as they are affected by the Force Majeure,
  shall be suspended during, but no longer than, the continuance of the Force
  Majeure.

                                   ARTICLE 13
                           Internal Revenue Provision

It is not the purpose or intention of this Agreement to create any partnership,
mining partnership or association, and neither- this Agreement nor the
operations hereunder shall be construed as creating any such legal relationship;
however, for income tax purposes only, the Parties agree that this Agreement
shall be governed in accordance with the "Provisions Concerning Taxation"
attached as Exhibit "G" to the Operating Agreement.

                                   ARTICLE 14
                                      Term

This Agreement shall remain in effect for so long as the Lease or any portion
thereof covering the Prospect Area remains in effect or the Operating Agreement
as to the Prospect Area remains in effect, whichever is later; provided,
however, that the obligations under the Confidentiality Agreement shall survive
termination of this Agreement.

<PAGE>

Participation Agreement dated March 28, 2005
Between GOM Shelf LLC and Ridgewood Energy Corporation
Page 11

                                   ARTICLE 15
                               General Provisions

15.1     This Agreement, together with all of its exhibits, is intended by the
         Parties to be a complete and final statement of the agreement of the
         Parties with respect to the subject matter hereof, and supersedes any
         prior oral or written statements or agreements.

15.2     Subject to all matters hereof, this Agreement shall be binding upon
         the Parties hereto and their respective successors and assigns.

15.3     Any capitalized term used in this Agreement and not specifically
         defined in this Agreement shall have the same meaning as in the
         Initiative.

15.4     In the event of any conflict between the provisions of the main body of
         this Agreement and any of its exhibits, the provisions of the main body
         of the Agreement shall prevail. In the event of any conflict between
         the provisions of this Agreement and the Initiative or the Operating
         Agreement, the provisions of this Agreement shall prevail, but only to
         the extent of such conflict.

15.5     Failure by any Party to comply with any of its obligations, agreements
         or conditions herein contained may be waived in writing, but not in any
         other manner, by the Party to whom such compliance is owed. No waiver
         of, or consent to a change in, any of the provisions of this Agreement
         shall be deemed or shall constitute a waiver of, or consent to a change
         in, other provisions hereof (whether or not similar), nor shall such
         waiver constitute a continuing waiver unless otherwise expressly
         provided.

15.6     None of the rights or liabilities derived from this Agreement is
         assignable by either Party except with the prior written consent of the
         other Party, such consent not to be unreasonably withheld, except with
         respect to assignments to an Affiliate.

15.7     This Agreement shall be binding upon, and shall inure to the benefit
         of, the Parties hereto and their respective permitted successors and
         assigns. This Agreement shall be a covenant running with the land and
         shall bind any assignee of a Party's right, title or interest in this
         Agreement.

15.8     The captions in this Agreement are for convenience only and shall not
         be considered part of or affect the construction or interpretation of
         any provision of this Agreement.

15.9     References herein to the singular include the plural, and vice versa.

15.10    The rights, duties, obligations and liabilities of the Parties under
         this Agreement shall be individual, not joint or collective. It is not
         the intention of the Parties to create, nor shall this Agreement be
         deemed or construed to create, a mining or other partnership, joint

Participation Agreement dated March 28, 2005
Between GOM Shelf LLC and Ridgewood Energy Corporation
Page 12

venture or association or a trust. This Agreement shall not be deemed or
construed to authorize any Party to act as an agent, servant or employee for any
other Party for any purpose whatsoever except as explicitly set forth in this
Agreement. In their relations with each other under this Agreement, the Parties
shall not be considered fiduciaries except as expressly provided in this
Agreement.

15.11    Each provision of this Agreement shall be construed as though all
         Parties participated equally in the drafting of the same. Consequently,
         the Parties acknowledge and agree that any rule of construction that a
         document is to be construed against the drafting Party shall not be
         applicable to this Agreement.

15.12    If and for so long as any provision of this Agreement shall be deemed
         to be judged invalid for any reason whatsoever, such invalidity shall
         not affect the validity or operation of any other provision of this
         Agreement except only so far as shall be necessary to give effect to
         the construction of such invalidity, and any such invalid provision
         shall be deemed severed from this Agreement without affecting the
         validity of the balance of this Agreement.

15.13    There shall be no modification of this Agreement except by written
         consent of all Parties.

IN WITNESS WHEREOF, the Parties entered into this Agreement as of the Effective
Date.

GOM SHELF LLC                                       RIDGEWOOD ENERGY CORPORATION
BY APACHE CORPORATION AS
MANAGING MEMBER

 BY: /s/ C.R. Harden                      BY: /s/ W. Greg Tabor
 -------------------                       -----------------
     C.R. Harden                              W. Greg Tabor
     Attorney in Fact                         Executive Vice President

<PAGE>

Participation Agreement dated March 28, 2005
Between GOM Shelf LLC and Ridgewood Energy Corporation
Page 13

                                   EXHIBIT "A"
    Attached to and made a part of that certain Participation Agreement dated
        March 28, 2005, by and between GOM Shelf LLC and Ridgewood Energy
                                   Corporation

                          DESCRIPTION OF PROSPECT AREA

OCS-G 00839 covering all of Block 94, West Delta Area, OCS Leasing Map,
Louisiana Map No. 8, containing 5,000 acres, more or less, limited as to depths
above 20,000 feet subsea; insofar and only insofar as said Lease covers the
S/2N/2, S/2N/2N/2 and N/2N/2S/2 and further described as being included within
the area outlined in red on the plat attached hereto as Exhibit "A-I" to that
certain Participation Agreement dated March 28, 2005 by and between GOM Shelf
LLC and Ridgewood Energy Corporation, containing approximately 1431.6774 acres,
more or less;

OCS-G 01497 covering all of Block 95, West Delta Area, OCS Leasing Map,
Louisiana Map No. 8, containing 5,000 acres, more or less, limited as to depths
above 20,000 feet subsea; insofar and only insofar as said Lease covers the
S/2NE/4NE/4, S/2NE/4, SE/4NW/4, S/2SW/4NW/4, NE/4SW/4NW/4, N/2S/2 and N/2S/2S/2
and further described as being included within the area outlined in red on the
plat attached hereto as Exhibit "A-I" to that certain Participation Agreement
dated March 28, 2005 by and between GOM Shelf LLC and Ridgewood Energy
Corporation, containing approximately 3203.0770 acres, more or less;

OCS-G 01498 covering all of Block 96, West Delta Area, OCS Leasing Map,
Louisiana Map No. 8, containing 3,665.07 acres, more or less, limited as to
depths above 20,000 feet subsea; insofar and only insofar as said Lease covers
the S/2S/2NE/4, N/2SE/4, NE/SW/4, SE/4NW/4SW/4 and NI2S/2S/2 and further
described as being included within the area outlined in red on the plat attached
hereto as Exhibit "A-I" to that certain Participation Agreement dated March 28,
2005 by and between GOM Shelf LLC and Ridgewood Energy Corporation, containing
approximately 2499.6584 acres, more or less.

<PAGE>

                                  EXHIBIT "B"
            Attached to and made a part of that certain Participation
            Agreement dated March 28, 2005, By and between GOM Shelf
                      LLC and Ridgewood Energy Corporation

              [LOGO]

<TABLE>
<CAPTION>

                                                                                    SAP NO: D&C X2-000NP, FAC Z1-00202

                                          BP AMERICA PRODUCTION CO.
                                          AUTHORIZATION FOR EXPENDITURE

<S>                                        <C>                                      <C>
DATE PREPARED:         2/7/2005           FINANCIAL MEMO NO:
OPERATOR:                                 AFE NO:                                   Little "e" Drilling ----
LEASE/UNIT/FACILITY:                      SURFACE LOCATION:     X-2481386 Y:92725
LEASE FLAC IDENTIFIER: 678261-00          BOTTOM HOLE LOC:      X-2481386 Y:90916
WELL NAME/NUMBER:      WD 95 #5 Drill     PROPOSED TOTAL DEPTH: 18350'MD            OIL WELL (Exploratory)
OPERATION CENTER:                         COUNTRY/STATE:
BP WORKING INTEREST:                      OPERATING FIELD:      GI 43 Field         SINGLE COMPLETION
JOA NUMBER:            VR-2519            HORIZON:              PD Sand
                                          (formation/prospect)
                                          ANTICIPATED START:    Jun-05
</TABLE>

PROJECT DESCRIPTION/COMMENTS TO PARTNERS:
The Saltamontes Prolundo prospect is located in West Delta 95 block and is
planned at an open-water location to be drilled to a PTD of 17,800' SSTVD. The
prospect consists of a three way structural closure against a down-to-the-basin
expansion fault and targets Upper Miocene sands found in the Grand Isle 47
Grasshopper discovery. This AFE requests funds to drill, evaluate and P&A if
necessary. Funds are also requested to perform facilities engineering design
work on the tripod requirements for the success case. This design work will
improve the project schedule by 3-4 months. At the time logging and testing
indicate an economic well, additional CAPEX will be requested of approximately
17MM$ for mud-line suspension and completion, and 10MM$ for facilities.

<TABLE>
<CAPTION>

   EXPENSE/CAPITAL/PXA                                                                     ESTIMATED COST
T-Tangible  I-Intangible               DESCRIPTION                              GROSS PRODUCER       GROSS DRY HOLE
------------------------               -----------                              --------------       --------------
<S>                    <C>                                                        <C>                   <C>
Capital-I              Shallow Hazard Survey and analysis                         $275,000.00           $275,000.00

Capital-I              Mobilization                                               $600,000.00           $600,000.00

Capital-I              Drilling and Evaluation***                              $15,955,000.00        $15,955,000.00

Capital-T              Drilling and Evaluation                                  $2,770,000.00         $2,770,000.00

Capital-I              Plug and Abandonment                                             $0.00           $450,000.00

Capital-I              De-mobilization                                            $180,000.00           $180,000.00

Capital-I              Facility Design Engineering                                $900,000.00           $900,000.00

Capital-I              Soil Boring                                                $100,000.00           $100,000.00

                       Please note the GOM ShelfLLC elects to maintain its own
                       insurance, therefore, do not charge for insurance.

                       ***Includes drilling($14,070,000), required drilling
                       specialists ($850,000), logging/testing ($910,000) and
                       geo-chemical sampling/analysis ($125,000).

                       TOTAL PROJECT COST:                                     $20,780,000.00        $21,230,000.00
</TABLE>

<TABLE>

<S>                    <C>                                                      <C>
PROJECT CONTACTS:      NAME               TITLE                                 PHONE NUMBER
                       ----               -----                                 ------------
                       Charlie Matcek                                           281-366-2881
                       Chuck Ware                                               281-366-0528
APPROVED BY:                         DATE:

--------------------------------------------------------------------------------------------------------------------------------
</TABLE>

                                          APPROVAL:     YES[X]   NO [_]

NOTICE TO NONOPERATOR: Costs shown on this form are estimates only. Nonoperators
should not consider these estimates as establishing any limit on the monies
which will be required to perform the proposed operation. Overhead will be
charged in accor COMPANY NAME/NONOPERATOR: GOM Shelf LLC by Apache Corp. as
Managing Member with the Joint Operating Agreement.

                       BY: J.A. Jeppesen   Date: 3/1/05
                           -------------         ------
                           Sr. Vice President, Gulf Coast Region

                       BY: /s/ J.A. Jeppesen
                           -----------------Participation Agreement

              Saltamontes Profundo-West Delta Blocks 94, 95 and 96

This Participation Agreement (this "Agreement") is made and entered into
effective as of the 14th day of April, 2005, by and between BP America
Production Company ("BP"), whose mailing address is 200 Westlake Park Blvd.,
Houston, Texas 77079 and Ridgewood Energy Corporation ("Ridgewood"), whose
mailing address is 11700 Old Katy Road, Suite 280, Houston, Texas 77079. BP and
Ridgewood are sometimes referred to herein individually as a "Party" and
collectively as the "Parties".

                                   Witnesseth

WHEREAS, BP is the owner of thirty-seven and one-half percent (37.50%) of the
right, title and interest in and to the oil and gas leases (the "Leases")
covering West Delta Blocks 94, 95 and 96, South Addition, Gulf of Mexico; and

WHEREAS, subject to certain terms and conditions contained herein, Ridgewood is
willing to accept and bear sixteen and one-tenth percent (16.10%) of the cost,
risk and expense of drilling, coring and logging the Initial Test Well (as
defined below) to earn an assignment from BP of an undivided eight and five
one-hundredths percent (8.05%) operating rights interest in and to those
portions of the Leases covering and affecting the Contract Area (as defined
below) limited to the ITW Earned Depth (as defined below).

NOW, THEREFORE, for and in consideration of the premises and mutual promises and
covenants to be kept and performed by the Parties as contained herein, and other
good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged and confessed, the Parties do hereby agree as follows:

                                    Article 1

                                   Definitions

For purposes of this Agreement, the following terms shall have the following
definitions:

1.1  AFE: An authorization for expenditure submitted pursuant to the Operating
     Agreement (as defined below).

1.2  Assignment: The form of Assignment of Operating Rights attached hereto as
     Exhibit "A"

1.3  BP Response Period: The timeframe BP has to respond to a proposal under the
     Operating Agreement (for example, thirty (30) days, forty-eight (48) hours,
     etc.) or, if BP

                                       1.

<PAGE>

     makes a proposal, the timeframe the Other Owners (as defined below) have to
     respond to BP's proposal.

1.4  BP Response Deadline: The date and time by which BP (or the Other Owners,
     as the case may be) must respond to a proposal under the Operating
     Agreement (i.e., the end of the BP Response Period).

1.5  Contract Area: The aliquot portions of the blocks as set forth below:

     i.   West Delta Block 94: S/2, S/2N/2, S/2N/2N/2

     ii.  West Delta Block 95: S/2, S/2NE/4, S/2NE/4NE/4, SE/4NW/4, E/2SW/4NW/4,
          SW/4SW/4NW/4

     iii. West Delta Block 96: SE/4, E/2SW/4, SW/4SW/4,  SE/4NW/4SW/4,  S/4NE/4.
          INSOFAR AND ONLY  INSOFAR as said lands  cover  those  depths from and
          below the stratigraphic  equivalent of the Top of the OP Sand (defined
          as the  stratigraphic  equivalent of the depth of 15,266 feet measured
          depth,  as seen in the  induction-electric  log  dated  5/4/72  in the
          Conoco WD 96#5 well (API# 17-719-20164-00)).

1.6  Gulf Coast Conditions: As used herein, includes, but is not limited to,
     either (1) mechanical difficulties which, in the sole discretion of BP,
     cannot be economically overcome after reasonable efforts to do so, or (2)
     heaving shale, cavity, excess pressure or water flow, loss of circulation
     or any other substance, formation, situation or condition, similar or
     dissimilar, which in the sole discretion of BP, reasonably and economically
     cannot be overcome by ordinary drilling methods or which renders drilling
     ahead under normal drilling procedures impractical, unwarranted or
     unreasonably hazardous.

1.7  ITW Earned Depth: The depths from the stratigraphic equivalent of the Top
     of the OP Sand down to and including 100 feet below the stratigraphic
     equivalent of the total depth drilled in the Initial Test Well.

1.8  Initial Test Well: The West Delta Block 95 No. 5 well to be drilled under
     this Agreement from a surface location of X:2481386, Y:92725 in West Delta
     Block 95, as further described in the AFE for the Initial Test Well (or any
     Substitute Well(s) for such Initial Test Well).

1.9  Operating Agreement: That certain CATCO Operating Agreement dated January
     1, 1989 (as amended), a copy of which is attached hereto as Exhibit "B."

1.10 Other Owners: Collectively, Chevron U.S.A. Inc. ("Chevron") and GOM Shelf
     LLC ("Apache"), who are the owners of the remaining sixty-two and one-half
     percent (62.50%) undivided interest in the Leases and are parties to the
     Operating Agreement.

                                       2.

<PAGE>

     The term "Other Owners" shall also apply to any successors or assigns of
     Chevron and/or Apache in the Leases.

1.11 Ridgewood Response Deadline: The date and time by which Ridgewood must
     respond to BP's notice of a proposal hereunder which shall be five (5)
     business days prior to the BP Response Deadline; provided, however, in the
     event BP's Response Period is forty eight (48) hours, such Ridgewood
     Response Deadline shall be twelve (12) hours prior to the BP Response
     Deadline.

1.12 STW Earned Depth: The depths from immediately below the base of the ITW
     Earned Depth down to and including 100 feet below the stratigraphic
     equivalent of the total depth drilled in the Second Test Well.

1.13 Second Test Well: The first well that is drilled subsequent to the Initial
     Test Well to test objective(s) below the ITW Earned Depth (or any
     Substitute Well(s) for such Second Test Well); provided, such well is not
     drilled to a depth below 20,000 feet subsea. If such well is drilled below
     a depth of 20,000 feet subsea, such well shall not be considered the Second
     Test Well under this Agreement.

1.14 Substitute Well: A well which: (i) is undertaken subsequent to the Test
     Well (as defined below) because such Test Well encounters Gulf Coast
     Conditions (and otherwise drilled in the same or similar manner as the
     original proposed Test Well, except that such new well may be drilled from
     a different surface location); (ii) is commenced on or before the earlier
     of the date occurring (x) one hundred and twenty (120) days after the
     release of the drilling rig for the Test Well or (y) after the lapse of a
     one hundred and twenty (120) day period without the drilling of any
     additional footage in the Test Well; and (iii) prior to commencement, is
     designated in writing by BP as a Substitute Well.

1.15 Test Well: Either the Initial Test Well or Second Test Well, as applicable.
     Each reference to the Test Well shall apply separately to the Initial Test
     Well and the Second Test Well.

List of Exhibits
----------------

Exhibit "A"- Form of Assignment of Operating Rights
Exhibit "B"- Operating Agreement (with Exhibits)
Exhibit "C" - AFE for the Initial Test Well
Exhibit "D" - Example of Well Cost Adjustment Calculation
Exhibit "E" -- Form of Operating Agreement Ratification
Exhibit "F" - Form of Tax Partnership

                                       3.

<PAGE>

                                    Article 2

                              The Initial Test Well
                              ---------------------

2.1  Prior to its execution hereof, Ridgewood has reviewed the AFE for the
     Initial Test Well attached hereto as Exhibit "C", along with the well plan
     attached thereto. The AFE is submitted and attached for informational
     purposes only. Ridgewood agrees that the Initial Test Well shall constitute
     an Exploratory Well under the Operating Agreement.

2.2  Ridgewood shall participate in and be obligated to bear and pay sixteen and
     one-tenth percent (16.10%) of the gross costs, risks, expenses and
     liabilities associated with all operations for the Initial Test Well
     conducted pursuant to the Operating Agreement until such time as actual
     operations for a completion of the Initial Test Well are commenced in
     accordance with Article 2.3 below (the "ITW Completion Time"). By way of
     example, but not limitation, if the Initial Test Well reaches its planned
     total depth and a decision is made pursuant to the Operating Agreement to
     postpone completion at such depth and deepen the Initial Test Well, such
     deepening operation shall be deemed prior to the ITW Completion Time and
     Ridgewood and BP will continue under the same promote and earning terms for
     the deepening operation as are stipulated herein for the Initial Test Well
     as originally proposed. Ridgewood's share of costs, risks, expenses and
     liabilities incurred after the ITW Completion Time shall be an undivided
     eight and five one hundredths percent (8.05%) with respect to the Initial
     Test Well, subject to the terms of this Agreement and the Operating
     Agreement.

2.3  If a proposal to complete the Initial Test Well at a depth below the Top of
     the OP Sand ("ITW Earning Completion") is made pursuant to the Operating
     Agreement, BP shall advise Ridgewood in writing of such ITW Earning
     Completion proposal, along with a copy of such ITW Earning Completion
     proposal, the estimated cost to conduct same, and shall advise Ridgewood of
     the BP Response Deadline. On or before the Ridgewood Response Deadline,
     Ridgewood shall advise BP in writing whether Ridgewood elects to
     participate in such ITW Earning Completion.

     (A) If Ridgewood elects to participate in such ITW Earning Completion, and
     same is conducted pursuant to the Operating Agreement, Ridgewood shall
     participate in same in accordance with the terms of this Agreement and the
     Operating Agreement. Upon providing BP written notice of its election to
     participate, Ridgewood shall have earned an assignment of a portion of BP's
     operating rights interest in and to the Contract Area limited to the ITW
     Earned Depth subject to the provisions of Article 5 hereof.

     (B) If Ridgewood elects not to participate in such ITW Earning Completion
     or fails to timely advise BP of its election regarding same, Ridgewood
     shall forfeit its right to earn any interests in the Contract Area and this
     Agreement shall immediately terminate and be of no further force and
     effect, except that Ridgewood shall remain responsible for its

                                       4.

<PAGE>

     proportionate share of all costs, expenses and liabilities incurred prior
     to such termination date.

2.4  If, prior to the ITW Completion Time or plugging and abandoning of the
     Initial Test Well, a proposal to temporarily abandon the Initial Test Well
     and release the drilling rig is made pursuant to the Operating Agreement,
     and same is not part of a completion proposal and is conducted pursuant to
     the Operating Agreement, Ridgewood shall participate in same and any future
     operations conducted on the Initial Test Well until the ITW Completion Time
     or plugging and abandoning of the Initial Test Well in accordance with the
     terms of this Agreement and the Operating Agreement; provided, however,
     subject to Article 12 hereof, if future operations are not commenced on or
     before the date occurring eighteen (18) months after the date the drilling
     rig is released from the Initial Test Well, this Agreement shall
     immediately terminate and be of no further force and effect, except that
     Ridgewood shall remain responsible for its proportionate share of all
     costs, expenses and liabilities incurred prior to such termination date,
     including, without limitation, its share of plugging and abandonment
     liability.

2.5  Notwithstanding anything herein to the contrary, if (i) the Initial Test
     Well or a Substitute Well therefore fails to reach a depth below the Top of
     the OP Sand due to Gulf Coast Conditions, but not otherwise, (ii) pursuant
     to the Operating Agreement, an ITW Earning Completion is not conducted on
     the Initial Test Well and the Initial Test Well is completed at a depth
     above the Top of the OP Sand or (iii) pursuant to the Operating Agreement,
     the Initial Test Well is plugged and abandoned, Ridgewood shall not earn
     any interests in the Contract Area pursuant to this Agreement and this
     Agreement shall immediately terminate and be of no further force and
     effect, except that Ridgewood shall remain responsible for its
     proportionate share of all costs, expenses and liabilities incurred prior
     to such termination date and if applicable, its proportionate share of
     plugging and abandonment costs. However, in the event of (ii) above, and if
     such Initial Test Well is successfully completed at a depth above the Top
     of the OP Sand, then there shall be a well cost adjustment between BP and
     Ridgewood pursuant to Article 7 hereof.

                                    Article 3

                              The Second Test Well
                              --------------------

3.1  If Ridgewood earns an assignment with respect to the Initial Test Well as
     provided in Article 2.3 above and pursuant to Article 5 below, Ridgewood
     shall have the option to elect to participate in the Second Test Well. If a
     proposal to drill the Second Test Well is made pursuant to the Operating
     Agreement on or before the date occurring three (3) years after the date
     the drilling rig is released from the Initial Test Well, BP shall advise
     Ridgewood in writing of such proposal, along with a copy of the proposal,
     the estimated cost to conduct same (including the Shallow Depth Estimate,
     as described below), and shall advise Ridgewood of the BP Response
     Deadline. On or before the Ridgewood

                                       5.

<PAGE>

     Response Deadline, Ridgewood shall advise BP in writing whether Ridgewood
     elects to participate in the proposed operation.

     (A)  If Ridgewood elects to participate in the proposed operation, and same
          is conducted pursuant to the Operating Agreement, Ridgewood shall
          participate in such proposed operation in accordance with the terms of
          this Agreement and the Operating Agreement.

     (B)  If Ridgewood elects not to participate in the proposed operation or
          fails to timely advise BP of its election to participate, Ridgewood
          shall forfeit its right to earn any additional interests below the,
          ITW Earned Depth in the Contract Area and this Agreement shall
          immediately terminate and be of no further force or effect as to all
          portions of the Contract Area below the ITW Earned Depth.

          If a proposal to drill the Second Test Well is not made pursuant to
          the Operating Agreement on or before the date occurring three (3)
          years after the date the drilling rig is released from the Initial
          Test Well, this Agreement shall immediately terminate and be of no
          further force or effect as to all portions of the Contract Area below
          the ITW Earned Depth.

3.2  If Ridgewood elects to participate in the Second Test Well pursuant to this
     Agreement and BP elects to participate in the Second Test Well pursuant to
     the Operating Agreement:

          (A) Ridgewood shall participate in and be obligated to bear and pay
          the gross costs, risks, expenses and liabilities associated with the
          sum of the following: (i) eight and five one-hundredths percent
          (8.05%) of the actual gross costs and expenses of all operations for
          the Second Test Well conducted pursuant to the Operating Agreement
          that are attributable to drilling and logging to the base of the ITW
          Earned Depth; (ii) eight and five one-hundredths percent (8.05%) of
          the difference between (x) the actual gross costs and expenses of all
          operations for the Second Test Well conducted pursuant to the
          Operating Agreement that are attributable to drilling and logging to
          the base of the ITW Earned Depth and (y) [the estimated gross cost and
          expenses of all operations for a well that would be drilling utilizing
          the same well bore path as the Second Test Well except that such well
          would be drilled to a total depth equal to the base of the ITW Earned
          Depth] (such bracketed language being referred to hereinafter as the
          "Shallow Depth Estimate"), (with such difference being referred to
          hereinafter as the "Shallow Promote"); and (iii) sixteen and one-tenth
          percent (16.10%) of the actual gross costs and expenses of all
          operations for the Second Test Well conducted pursuant to the
          Operating Agreement that are not captured by (i) above. The above
          calculated share of costs, risks, expenses and liabilities shall be
          effective until such time as actual operations for a completion of the
          Second Test Well are commenced in accordance with Article 3.2(B) below
          (the

                                       6.

<PAGE>

          "STW Completion Time"). Ridgewood's share of costs, risks, expenses
          and liabilities incurred after such STW Completion Time shall be an
          undivided eight and five one hundredths percent (8.05%) with respect
          to the Second Test Well, subject to the terms of this Agreement and
          the Operating Agreement.

          In the event Ridgewood disagrees with BP's Shallow Depth Estimate,
          Ridgewood shall provide BP with written notice of such disagreement
          within three (3) days of Ridgewood's receipt thereof. Upon receipt of
          such written notice from Ridgewood, the Parties shall enter into good
          faith negotiations and attempt to agree on such Shallow Depth
          Estimate. In the event the Parties cannot agree on a Shallow Depth
          Estimate within two (2) days of Ridgewood's notice, the Parties shall
          mutually agree on and employ a drilling consultant to resolve the
          matter and determine a Shallow Depth Estimate. The determination by
          the drilling consultant shall be conclusive and binding upon both
          Parties. The cost of the drilling consultant shall be borne fifty
          percent (50%) by Ridgewood and fifty percent (50%) by BP.

     (B)  If a proposal to complete the Second Test Well at a depth below the
          ITW Earned Depth ("STW Earning Completion") is made, BP shall advise
          Ridgewood in writing of such STW Earning Completion proposal, along
          with a copy of such STW Earning Completion proposal and the estimated
          cost to conduct same, and shall advise Ridgewood of the BP Response
          Deadline. On or before the Ridgewood Response Deadline, Ridgewood
          shall advise BP in writing whether Ridgewood elects to participate in
          such STW Earning Completion.

               (1) If Ridgewood elects to participate in such STW Earning
               Completion and same is conducted pursuant to the Operating
               Agreement, Ridgewood shall participate in same in accordance with
               the terms of this Agreement and the Operating Agreement. Upon
               providing BP written notice of its election to participate,
               Ridgewood shall have earned an assignment of a portion of BP's
               operating rights interest in and to the Contract Area limited to
               the STW Earned Depth subject to the provisions of Article 5
               hereof.

               (2) If Ridgewood elects not to participate in such STW Earning
               Completion or fails to timely advise BP of its election regarding
               same, Ridgewood shall forfeit its right to earn any additional
               interests in the Contract Area and this Agreement shall
               immediately terminate and be of no further force or effect as to
               all portions of the Contract Area below the ITW Earned Depth,
               except that Ridgewood shall remain responsible for its
               proportionate share of all costs, expenses and liabilities
               associated with the terminated portions incurred prior to such
               termination date.

3.3  If Ridgewood elects to participate in the Second Test Well pursuant to this
     Agreement, but BP elects not to participate in the Second Test Well
     pursuant to the Operating

                                       7.

<PAGE>

     Agreement and the Second Test Well is proposed in a portion of the Contract
     Area in which Ridgewood has earned an interest in depths below the ITW
     Earned Depth from third parties:

     (A) The Second Test Well shall be drilled pursuant to the Operating
     Agreement and BP shall be designated as a Non-Participating Party
     thereunder.

     (B) If an STW Earning Completion is proposed, Ridgewood shall advise BP in
     writing as to whether Ridgewood has elected to participate in such STW
     Earning Completion proposal pursuant to the Operating Agreement.

          (1) If Ridgewood elects to participate in such STW Earning Completion
          pursuant to the Operating Agreement and same is conducted pursuant to
          the Operating Agreement, Ridgewood shall be deemed to have elected to
          participate in the STW Earning Completion for purposes of this
          Agreement and shall pay BP by wire transfer within thirty (30) days of
          Ridgewood's election to participate a sum equal to (i) eight and five
          one-hundredths percent (8.05%) of the Shallow Promote (as defined in
          Article 3.2(A)(ii)) plus (ii) eight and five one-hundredths percent
          (8.05%) of the actual gross costs and expenses of all operations for
          the Second Test Well conducted pursuant to the Operating Agreement
          that are not actual gross costs and expenses of operations for the
          Second Test Well conducted pursuant to the Operating Agreement
          attributable to drilling and logging to the base of the ITW Earned
          Depth. Upon such payment, Ridgewood shall have earned an assignment of
          a portion of BP's operating rights interest in and to the Contract
          Area limited to the STW Earned Depth subject to the provisions of
          Article 5 hereof. To the extent any interest earned pursuant to this
          Article 3.3 is subject to non-consent penalties as a result of BP's
          elections pursuant to the Operating Agreement, such interest shall
          remain subject to such non-consent penalties notwithstanding any
          assignment made pursuant hereto.

          (2) If Ridgewood elects not to participate in such STW Earning
          Completion pursuant to the Operating Agreement or fails to timely make
          such election pursuant to the Operating Agreement, Ridgewood shall be
          deemed to have elected not to participate in the STW Earning
          Completion for purposes of this Agreement and shall forfeit its right
          to earn any additional interests in the Contract Area and this
          Agreement shall immediately terminate and be of no further force or
          effect as to all portions of the Contract Area below the ITW Earned
          Depth, except that Ridgewood shall remain responsible for its
          proportionate share of all costs, expenses and liabilities associated
          with the terminated portions incurred prior to such termination date.

3.4  If Ridgewood elects to participate in the Second Test Well pursuant to this
     Agreement,

                                       8.

<PAGE>

     but BP does not desire to participate in the Second Test Well and the
     Second Test Well is proposed in a portion of the Contract Area in which
     Ridgewood has not earned an interest in depths below the ITW Earned Depth
     from third parties:

     (A) BP shall elect to participate in the Second Test Well for purposes of
     the Operating Agreement and Ridgewood shall participate in and be obligated
     to bear and pay thirty-seven and one-half percent (37.50%) of the gross
     costs, risks, expenses and liabilities associated with all operations for
     the Second Test Well conducted pursuant to the Operating Agreement until
     Payout (as defined below).

     (B) If an STW Earning Completion. is proposed, BP shall advise Ridgewood in
     writing of such STW Earning Completion proposal, along with a copy of such
     STW Earning Completion proposal and the estimated cost to conduct same, and
     shall advise Ridgewood of the BP Response Deadline. On or before the
     Ridgewood Response Deadline, Ridgewood shall advise BP in writing whether
     Ridgewood elects to participate in such STW Earning Completion.

          (1) If Ridgewood elects to participate in such STW Earning Completion
          pursuant to the Operating Agreement and same is conducted pursuant to
          the Operating Agreement:

               (a) Ridgewood shall be deemed to have elected to participate in
               the STW Earning Completion for purposes of this Agreement and
               shall pay BP by wire transfer within thirty (30) days of
               Ridgewood's election to participate a sum equal to (i) eight and
               five one-hundredths percent (8.05%) of the Shallow Promote (as
               defined in Article 3.2(A)(ii)) plus (ii) eight and five
               one-hundredths percent (8.05%) of the actual gross costs and
               expenses of all operations for the Second Test Well conducted
               pursuant to the Operating Agreement that are not actual gross
               costs and expenses of operations for the Second Test Well
               conducted pursuant to the Operating Agreement attributable to
               drilling and logging to the base of the ITW Earned Depth. Upon
               such payment, Ridgewood shall have earned an assignment of a
               portion of BP's operating rights interest in and to the Contract
               Area limited to the STW Earned Depth subject to the provisions of
               Article 5 hereof.

               (b) Ridgewood shall be entitled to receive all revenues from
               production attributable to BP's remaining twenty-nine and
               forty-five one hundredths percent (29.45%) interest in the Second
               Test Well until such time as Ridgewood has recouped the
               applicable non-consent penalty as determined pursuant to Articles
               10 and 12 of the Operating Agreement, which Articles are
               incorporated herein by reference (such time being

                                       9.

<PAGE>

               referred to herein as "Payout").

              (c) Ridgewood's share of costs incurred after Payout shall be an
              undivided twenty percent (8.05%) with respect to the Second Test
              Well, subject to the terms of this Agreement and the Operating
              Agreement.

          (2) If Ridgewood elects not to participate in such STW Earning
          Completion or fails to timely advise BP of its election regarding
          same, Ridgewood shall forfeit its right to earn any additional
          interests in the Contract Area and this Agreement shall immediately
          terminate and be of no further force or effect as to all portions of
          the Contract Area below the ITW Earned Depth, except that Ridgewood
          shall remain responsible for its proportionate share of all costs,
          expenses and liabilities associated with the terminated portions
          incurred prior to such termination date.

3.5  If, prior to the STW Completion Time or plugging and abandoning of the
     Second Test Well, a proposal to temporarily abandon the Second Test Well
     and release the drilling rig is made pursuant to the Operating Agreement,
     and same is conducted pursuant to the Operating Agreement, Ridgewood shall
     participate in same and any future operations conducted on the Second Test
     Well until the STW Completion Time in accordance with the terms of this
     Agreement and the Operating Agreement; provided, however, subject to
     Article 12 hereof, if future operations are not commenced on or before the
     date occurring eighteen (18) months after the date the drilling rig is
     released from the Second Test Well, this Agreement shall immediately
     terminate and be of no further force and effect as to all portions of the
     Contract Area below the ITW Earned Depth, except that Ridgewood shall
     remain responsible for its proportionate share of all costs, expenses and
     ,liabilities incurred prior to such termination date, including, without
     limitation, its share of plugging and abandonment liability.

3.6  Notwithstanding anything herein to the contrary, if (i) the Second Test
     Well or a Substitute Well therefore fails to reach a depth below the ITW
     Earned Depth due to Gulf Coast Conditions, but not otherwise, (ii) pursuant
     to the Operating Agreement, an STW Earning Completion is not conducted on
     the Second Test Well and the Second Test Well is completed at a depth
     above the base of the ITW Earned Depth, or (iii) pursuant to the Operating
     Agreement, the Second Test Well is plugged and abandoned, Ridgewood shall
     not earn any additional interests in the Contract Area pursuant to this
     Agreement and this Agreement shall immediately terminate and be of no
     further force and effect as to all portions of the Contract Area below the
     ITW Earned Depth, except that Ridgewood shall remain responsible for its
     proportionate share of all costs, expenses and liabilities associated with
     the terminated portions incurred prior to such termination date. However,
     in the event of (ii) above, and if such Second Test Well is successfully
     completed at a depth above the base of the ITW Earned Depth, then the cost
     of drilling, completing, and equipping the Second Test Well (less any
     amounts attributable to Article 3.2 (A)(ii)

                                       10.

<PAGE>

above) from the surface to a depth one hundred feet (100') below the base of the
completed zone, shall be allocated pursuant to the Operating Agreement.

                                    Article 4

                            Drilling of the Test Well
                            -------------------------

4.1  BP shall commence, or cause to be commenced, the Initial Test Well on or
     before July 1, 2005; provided, however, the sole consequence of BP's
     failure to timely commence, or cause to be commenced, such Initial Test
     Well shall be forfeiture of this Agreement.

4.2  After commencement, BP agrees to drill the Test Well in accordance with the
     provisions of the Operating Agreement. 4.3 In the event BP elects to drill
     a Substitute Well for the Test Well, such Substitute Well shall be
     considered and treated for all purposes as though the same were the Test
     Well, and all references in this Agreement to the Test Well shall also
     include such Substitute Well. There shall not be a limit on the number of
     Substitute Wells that BP may elect to drill for the Test Well (or any
     Substitute Well therefore) provided the provisions of Article 1.14 are
     satisfied.

                                    Article 5

                       Assignment(s) of Oil And Gas Leases
                       -----------------------------------

5.1  If Ridgewood satisfies its requirements in Article 2 or 3, as applicable,
     then as of the ITW Completion Time or STW Completion Time, as the case may
     be, Ridgewood shall be entitled to an assignment of operating rights from
     BP as hereinafter set forth and subject to the conditions, exceptions,
     reservations and agreements hereinafter contained effective as of ITW
     Completion Time or STW Completion Time, as the case may be. If Ridgewood i
     s entitled to an assignment, BP shall assign to Ridgewood an undivided
     eight and five one-hundredths percent of 8/8ths (8.05% of 8/8ths) operating
     rights interest in and to the Leases limited both geographically and
     horizontally to the Contract Area limited to the ITW Earned Depth or the
     STW Earned Depth, as the case may be, together with all rights in oil and
     gas produced and marketed therefrom.

5.2  Any assignment earned by Ridgewood from BP hereunder shall be in the form
     attached hereto as Exhibit "A" and shall be without warranty of title,
     either express or implied, except as to claims of all persons claiming an
     interest by, through or under BP, but not otherwise, and with full
     subrogation and substitution in and to all actions in warranty. The
     assigned interest will be transferred to Ridgewood free and clear of all
     liens, encumbrances, burdens and claims arising by, through or under BP,
     except for BP's proportionate share of lessor's royalties, rentals and
     other obligations pursuant to the terms of the Leases and any non-consent
     penalties burdening such interest pursuant to the

                                       11.

<PAGE>

     terms of the Operating Agreement. BP does not warrant title to any portion
     of the Contract Area or the Leases or agree to convey to Ridgewood any
     better title thereto than BP has on the effective date of this Agreement.

5.3  In the event said Leases cover less than the entire mineral estate or the
     interest owned by BP is less than the entire leasehold estate, both the
     interest assigned by BP in any assignment pursuant hereto and Ridgewood's
     share of costs, risks, expenses and liabilities assumed herein shall be
     reduced proportionately.

5.4  Ridgewood agrees to be bound by the agreements and contracts to which the
     interests assigned herein are subject and to assume the rights and
     obligations of BP in such agreements and contracts, to the extent of the
     interest acquired by Ridgewood, including, but not limited to, the
     Operating Agreement.

5.5  Ridgewood covenants and agrees that prior to the time that it may become
     entitled to an assignment pursuant to this Agreement, it shall not transfer
     or assign this Agreement, or the interests assigned herein, without the
     prior written consent of BP. Any assignment without BP's consent in
     violation of this provision shall be, at BP's sole election, null and void
     and of no force or effect. Consent by BP to any one assignment or transfer
     shall not be construed as consent to any further or future assignment or
     transfer, it being expressly understood that BP's prior written consent
     shall be required for any assignment or transfer by Ridgewood, and any of
     its successors or assigns. In the event the right to assign is granted, BP
     shall nevertheless hold Ridgewood responsible for compliance with the terms
     and conditions hereof. Any assignment by Ridgewood, or its subsequent
     assignees, of any interest in all or any portion of the Leases shall be
     made expressly subject to this Agreement and the assignee therein shall
     expressly agree to be ,bound by the terms and provisions of this Agreement
     and the Operating Agreement.

5.6  Except as provided in (i) and (ii) below and subject to Article 12 hereof,
     at any time or times after Ridgewood has earned an assignment of operating
     rights interest pursuant to this Agreement, if all production from that
     portion of the Contract Area earned by Ridgewood hereunder should cease for
     any cause, and a lapse of more than one (1) year without the recommencement
     of production from such portion of the Contract Area occurs, BP may
     terminate this Agreement and any transfer of operating rights interest
     executed pursuant hereto; whereupon Ridgewood shall re-convey to BP, by
     means of a recordable written instrument effective as of the end of such
     one (1) year time period, the operating rights interest Ridgewood acquired
     from BP pursuant to this Agreement, such operating rights interest to be
     returned to BP free and clear of any lien, privilege, mortgage, other
     encumbrance, overriding royalty interest, payment out of production, and/or
     contract created or entered into by Ridgewood and affecting such
     transferred premises. Notwithstanding anything to the contrary contained
     above in this Article 5.6,

                                       12.

<PAGE>

     the assignment from Ridgewood to BP shall not relieve Ridgewood from any
     obligations or liability incurred prior to the effective date of such
     assignment to BP.

     The above provisions of Article 5.6 shall not be applicable if (i) a well
     or well(s) exist in that portion of the Contract Area earned by Ridgewood
     hereunder which are capable of producing oil and/or gas in "paying
     quantities" (as defined below) from such portion of the Contract Area, or
     (ii) a proposal to drill, rework, recomplete, or sidetrack a well to such
     portion of the Contract Area ("Extending Operation(s)") is made pursuant to
     the Operating Agreement and such Extending Operation(s) is timely commenced
     and continuously prosecuted; provided, if such Extending Operation(s) fails
     to result in a well capable of production in "paying quantities", then the
     above provisions of Article 5.6 shall continue to not be applicable for
     only so long as such Extending Operation(s) are commenced without a time
     period in excess of one hundred eighty (180) days elapsing between the
     commencement of actual operations for one such Extending Operation(s) and
     the commencement of actual operations for the next subsequent Extending
     Operation(s).

     For purposes of this Article 5.6, the term "paying quantities" shall mean
     in sufficient quantities such that the net revenue generated from same is
     in excess of the monthly operating costs allocated to such well pursuant to
     the Operating Agreement.

                                    Article 6

                        Cash Calls and Performance Bonds
                        --------------------------------

6.1  Subject to confirmation by Ridgewood of BP having contracted a rig to drill
     the Initial Test Well, then within thirty (30) days of receipt by Ridgewood
     of a written notice by BP that the anticipated spud date for the Initial
     Test Well will occur on a date equal to or less than thirty (30) days from
     the date of said notice, Ridgewood shall advance to BP by wire transfer its
     respective share of estimated expenditures associated with the AFE for the
     Initial Test Well. As to subsequent operations in which Ridgewood elects to
     participate, Ridgewood shall advance to BP by wire transfer its respective
     share of estimated expenditures for such subsequent operations on or before
     the date occurring ten (10) business days after Ridgewood's election to
     participate is delivered to BP. In addition to the above, Ridgewood shall
     also advance to BP by wire transfer its respective share of estimated
     expenditures associated with any supplemental AFEs for operations in which
     Ridgewood is obligated to participate within ten (10) days of Ridgewood's
     receipt thereof. BP shall adjust each billing to give credit for advances
     received from Ridgewood In the event Ridgewood fails to timely advance its
     respective share of estimate expenditures, then, BP will immediately notify
     Ridgewood of its advance being due, and Ridgewood shall have a twenty-four
     (24) hour period from receipt of such notice by BP to advance its
     respective share of estimate expenditures by wire transfer and

                                       13.

<PAGE>

     if Ridgewood fails to do so, then, at BP's sole election, Ridgewood shall
     be deemed to have elected not to participate in such operation for which it
     did not timely advance its respective share of estimated expenditures and
     BP may, in its sole discretion, immediately terminate all or any portion of
     this Agreement.

     Notwithstanding anything herein to the contrary, once the Operating
     Agreement becomes applicable as to interests earned by Ridgewood pursuant
     to this Agreement, the !above provisions of this Article 6.1 shall not be
     applicable to such earned interests and the ability of BP to make cash
     calls with respect to such earned interests shall be governed by the terms
     of the Operating Agreement.

6.2  On or before the date occurring thirty (30) days after Ridgewood's election
     to participate in the ITW Earning Completion, Ridgewood shall establish an
     escrow account in an amount of Ridgewood's earned interest percentage of
     the estimated costs of plugging and abandoning the Initial Test Well, which
     estimated amount shall be provided by BP to Ridgewood in writing. The
     escrow agreement (the "Escrow Agreement") establishing and governing such
     escrow account shall be in a form acceptable to BP. Upon subsequent
     elections to participate by Ridgewood or at payout of any operations in
     which Ridgewood elected not to participate under the Operating Agreement,
     BP shall provide Ridgewood with written estimates of additional costs for
     plugging and abandonment associated with such elections, and within thirty
     (30) days of Ridgewood's receipt thereof, Ridgewood shall increase the
     escrowed amount in the amount of such estimates. In addition, BP shall have
     the ability to make an annual redetermination of the required escrowed
     amount and require Ridgewood to increase/decrease the escrowed amount as
     necessary. In the event Ridgewood fails to establish an escrow account in a
     form acceptable to BP or fails to increase the escrowed amount as required
     by this Agreement, BP may establish such escrow account itself and, at BP's
     sole discretion, either invoice Ridgewood for the cost to establish such
     escrow account, including, without limitation, the escrowed amount or
     recover the cost to establish such escrow account and the escrowed amount
     from Ridgewood's share of production.

     In the event Ridgewood disagrees with any of BP's estimates of the costs
     associated with plugging and abandonment, Ridgewood shall provide BP with
     written notice of such disagreement within ten (10) days of Ridgewood's
     receipt thereof. Upon receipt of such written notice from Ridgewood, the
     Parties shall enter into good faith negotiations and attempt to agree on
     such estimates. In the event the Parties cannot agree on an estimate within
     ten (10) days of Ridgewood's notice, the Parties shall mutually agree on
     and employ a plugging and abandonment consultant to resolve the matter and
     determine such estimates. The determination by the plugging and abandonment
     consultant shall be conclusive and binding upon both Parties: The cost of
     the plugging and abandonment consultant shall be borne fifty percent (50%)
     by Ridgewood and fifty percent (50%) by BP.

                                       14.

<PAGE>

                                    Article 7

                              Well Cost Adjustments
                              ---------------------

7.1  For purposes of this Article 7, "Total Gross Cost" shall mean the total
     gross cost incurred in the initial drilling, logging, casing of the well
     down to the base of the zone which is the target of the completion
     operation depreciated by an amount equal to ten percent (10%) of said total
     gross cost per year from the date the well reached its total depth to the
     date the completion operation is commenced (prorated to account for
     fractional years). Such "total gross cost" shall include, without
     limitation, intangible drilling costs, tangible drilling costs, surface
     equipment and drilling overhead.

7.2  To the extent application of this Article 7 is required by Article 2.5 of
     this Agreement, the depreciated well cost adjustment shall be calculated as
     follows:

     (A) If BP elects to participate in the completion operation provided for in
     Article 2.5 (ii), BP shall remit to Ridgewood a depreciated well cost
     adjustment amount which shall be calculated by multiplying twelve percent
     (12%) times the Total Gross Cost. Said well cost adjustment shall be due
     and payable from BP to Ridgewood by wire transfer within thirty (30) days
     after the ITW completion.

     (B) If BP elects not to participate in the completion operation provided
     for in Article 2.5 (ii), BP shall be deemed to be a Non-Participating Party
     (as defined in the Operating Agreement). Any depreciated well cost
     adjustment amount shall be calculated pursuant to the formula in Article
     7.2(A) above, but such well cost adjustment amount shall be recouped by
     Ridgewood from BP's net proceeds, if any, from the well after the
     Participating Parties (as defined in the Operating Agreement) recoup the
     non-consent penalty amounts provided in the Operating Agreement.

7.3  By way of example and not of limitation, attached hereto as Exhibit "D" is
     an example of a well cost adjustment calculation utilizing the above
     methodology.

                                    Article 8

                Operator and Applicability of Operating Agreement
                -------------------------------------------------

8.1  BP shall be the Operator of the Test Well as provided in the Operating
     Agreement. Simultaneously with each assignment to Ridgewood pursuant to
     Article 5 above, if made, Ridgewood shall execute a ratification of the
     Operating Agreement attached hereto as Exhibit "E" as to the interests
     earned pursuant to such assignment. Except as provided otherwise in this
     Agreement, all operations on the Test Well and all subsequent operations on
     the Contract Area shall be conducted pursuant to the terms and conditions
     of the Operating Agreement.

                                       15.

<PAGE>

                                    Article 9

                       Production Handling and Processing
                       ----------------------------------

9.1  Ridgewood acknowledges that a formal production handling and processing
     arrangement does not currently exist to handle and process production from
     the Leases and the Contract Area. Therefore, BP does not represent or
     guarantee that Ridgewood will have appropriate means to handle and process
     its share of production from the Test Well in the event that the Test Well
     is completed as a well capable of commercial production nor does BP
     represent or guarantee that any production handling facilities will have
     capacity to handle such production; provided, as between BP and Ridgewood,
     if limited capacity is available on an existing production handling
     facility and the Initial Test Well is produced at a rate less than its
     maximum production rate, then the reduced production volumes will be
     pro-rated between BP and Ridgewood based on their working interest
     ownership of the Initial Test Well. Upon completion of the Test Well as a
     well capable of commercial production, BP will endeavor to facilitate the
     negotiation of a Production Handling Agreement between Ridgewood and the
     owners of the applicable production handling and processing facilities.

                                   Article 10

                             Liability and Insurance
                             -----------------------

10.1 Ridgewood shall secure and maintain the following insurance coverages for
     purposes of this Agreement:

     a) Comprehensive General Liability Insurance suitably endorsed for maritime
     operations (including contractual coverage), excluding products, with a
     minimum limit of Five Million Dollars (US$5,000,000) for each accident for
     bodily injuries or death and property damage.

     b) Extra Expense Insurance including Well Control Coverage, Pollution,
     Extra Expense and Care, Custody and Control Coverage in the minimum amount
     of Ten Million Dollars (US$10,000,000).

10.2 Ridgewood shall name BP as an additional named insured on all of the
     policies hereinabove. BP shall hold the same benefit and insurance coverage
     as Ridgewood and there shall be no exclusions, endorsements or other
     special policy provisions which provide that BP shall have restricted or
     limited insurance coverage that varies in any respect from the insurance
     coverage.

                                       16.

<PAGE>

10.3 All of the insurance policies listed herein obtained by Ridgewood shall
     also be endorsed as follows: "To eliminate controversies, the expense and
     inconvenience thereto, as between Ridgewood and BP, it is agreed that the
     underwriters, insurers and insurance carriers of the Party named as
     additional insured shall not have any right of subrogation (equitable or by
     assignment, express or implied, loan receipt of otherwise) against the
     named insured Party or its insurers, and the right of subrogation is
     expressly waived."

10.4 Ridgewood shall secure a certificate of insurance from its primary insurers
     and shall also secure copies of the insurance policies covering the
     required insurance listed hereinabove and shall furnish same to BP.

10.5 The above insurance coverages shall be in addition to any insurance
     required by the Operating Agreement.

                                   Article 11

                                 Tax Provisions
                                 --------------

11.1 In order to properly allocate the intangible drilling costs and other tax
     benefits of the costs incurred hereunder, BP and Ridgewood hereby agree to
     enter into the Tax Partnership attached hereto as Exhibit "F," with BP
     acting as Tax Reporting Partner. Any costs incurred by BP in establishing
     and administering the Tax Partnership will be billed by BP to Ridgewood
     with Ridgewood being responsible for twenty-two percent (22%) of such costs
     and BP being responsible for seventy-eight percent (78%) of such costs.
     Notwithstanding any provision in this Agreement, to the effect that the
     rights and liabilities of the Parties are several, not joint or collective,
     and this Agreement and the activities and operations hereunder do not
     constitute a partnership under state law, each Party elects not to be
     excluded from the application of all or any part of the provisions of
     Subchapter K, Chapter 1, Subtitle A, of the Internal Revenue Code of 1986,
     as amended, or similar provisions of applicable state laws.

                                   Article 12

                                  Force Majeure
                                  -------------

12.1 All obligations imposed by this Agreement on each Party, except for the
     payment of money, shall be suspended and all periods of time for exercising
     any rights hereunder shall be extended while compliance is prevented, in
     whole or in part, by a labor dispute, fire, flood, war, civil disturbance,
     or act of God; by laws; by governmental rules, regulations, or orders; by
     governmental action or governmental delay; by inability to secure materials
     or equipment; or by any other cause, whether similar or dissimilar, beyond
     the reasonable control of the said Party; provided, however, that
     performance

                                       17.

<PAGE>

     shall be resumed within a reasonable time after such cause has been
     removed; and provided further that no Party shall be required against its
     will to settle any labor dispute. Whenever a Party's obligations or rights
     are suspended or extended hereunder, such Party shall immediately notify
     the other Party, giving full particulars of the reason for such suspension
     or extension, and such Party shall thereafter diligently endeavor to remove
     or correct the cause of such force majeure event as soon as reasonably
     possible.

                                   Article 13

                                 Representations
                                 ---------------

13.1 Ridgewood represents and warrants that this Agreement and any interest
     acquired hereunder (a) are being entered into and acquired for its own
     account and not with a view to distribution, (b) have not and will not be
     registered under the Securities Act of 1933, as amended, or the securities
     laws of any state (collectively, the "Acts") in reliance on exemptions
     therefrom and/or this and the other representations by Ridgewood in this
     Article 13.1, and (c) will not be sold or otherwise transferred except in
     accordance with the registration requirements of the Acts or pursuant to an
     exemption therefrom.

13.2 BP does not make any representation or warranty, either express or implied,
     as to the accuracy, completeness or materiality of any data, information,
     records or materials made available in connection with this Agreement.
     WITHOUT LIMITATION TO THE GENERALITY OF THE FOREGOING AND EXCEPT AS
     OTHERWISE PROVIDED IN THE ASSIGNMENT, BP EXPRESSLY DISCLAIMS AND NEGATES
     ANY WARRANTY, EXPRESS OR IMPLIED AS TO (1) TITLE, (2) MERCHANTABILITY, (3)
     FITNESS FOR A PARTICULAR PURPOSE, OR (4) CONFORMITY OF THE DATA TO SAMPLES
     OR MODELS. Ridgewood confirms that it, or its, agents or representatives,
     had access to and an opportunity to inspect relevant data related to the
     interests to be acquired hereunder which it deemed necessary to make an
     informed investment judgment with respect to such interests and that it has
     the knowledge and experience in financial and business matters in general
     and in oil and gas investments in particular, including investments in the
     oil and gas exploration and production industry, and that it is capable of
     evaluating the merits and risks of this Agreement and any interests
     acquired hereunder.

                                   Article 14

                                     Default
                                     -------

14.1 If Ridgewood makes any default in any term, covenant or condition of this
     Agreement, BP may give Ridgewood written notice stating the nature of such
     default. If Ridgewood fails to commence to remedy such default within
     thirty (30) days after receipt of such notice or fails to continue to
     remedy such default, BP may, by notice, in writing to Ridgewood, cancel and
     terminate all or any portion of the interest of Ridgewood

                                       18.

<PAGE>

     hereunder, and it shall be lawful for BP to reenter upon the Contract Area
     (or any part thereof in the name of the whole) and to repossess and enjoy
     same.

14.2 The rights hereby granted to BP shall be in addition to and not in
     substitution for any other right or remedy which BP may have hereunder and,
     specifically, the existence or the exercise of such rights shall not serve
     to deprive BP, either wholly or partially, of any other right or remedy at
     law or in equity, including damages and indemnity.

14.3 Notwithstanding the preceding clauses of this Article, but subject to
     Article 5.6, no termination or cancellation as hereinbefore provided shall
     apply to any portion of the Contract Area in which Ridgewood has earned an
     interest prior to the default.

                                   Article 15

                                 Lease Payments
                                 --------------

15.1 If any delay rental payment, shut-in well payments or minimum royalty
     payments for the Leases should become due and payable, whether before or
     after Ridgewood has earned any assignments, BP shall make a bona fide
     effort to pay such lease payments, but shall not be responsible to
     Ridgewood for losses or damages resulting from its failure to do so.

                                   Article 16

                                 INDEMNIFICATION
                                 ---------------

16.1 TO THE EXTENT OF RIDGEWOOD'S PERCENTAGE SHARE OF COSTS, RISKS, EXPENSES AND
     LIABILITIES ASSUMED HEREIN, RIDGEWOOD AGREES TO PROTECT, DEFEND, INDEMNIFY,
     AND HOLD BP, ITS AFFILIATES, AND THEIR RESPECTIVE OFFICERS, DIRECTORS,
     AGENTS, SERVANTS, AND EMPLOYEES, HARMLESS FROM AND AGAINST ANY AND ALL
     CLAIMS, DEMANDS, COSTS, LOSSES, EXPENSES, INCLUDING COURT COSTS AND
     ATTORNEYS FEES, SUITS AND JUDGMENTS FOR PERSONAL INJURY, PROPERTY DAMAGE OR
     ENVIRONMENTAL DAMAGE RESULTING DIRECTLY OR INDIRECTLY FROM OR ARISING OUT
     OF THE OPERATIONS CONTEMPLATED BY TO THIS AGREEMENT TO THE FULLEST EXTENT
     WHICH THE LAW WILL ALLOW, ALSO EXPRESSLY INCLUDING ANY OF THE SAME THAT MAY
     BE CAUSED IN WHOLE OR IN PART BY THE NEGLIGENCE OR OTHER FAULT OF ANY OF
     THE ABOVE DESCRIBED INDEMNITEES (EXCEPTING ONLY THOSE CLAIMS CAUSED BY THE
     INDEMNITEES' GROSS NEGLIGENCE OR WILLFUL MISCONDUCT); PROVIDED THAT BP
     SHALL HAVE THE RIGHT, IF IT SO ELECTS, TO PARTICIPATE AT ITS OWN COST AND
     EXPENSE IN THE DEFENSE OF ANY SUIT TO WHICH ANY SUCH INDEMNITEES ARE

                                       19.

<PAGE>

     MADE A PARTY WITHOUT RELIEVING RIDGEWOOD OF THE PRIMARY OBLIGATION TO
     DEFEND SUCH ACTION.

                                   Article 17

                            Miscellaneous Provisions
                            ------------------------

17.1 Relationship of the Parties. It is not the purpose or intention of this
     Agreement to create, and this Agreement shall never be construed as
     creating, a joint venture, mining partnership or other relationship whereby
     any Party shall be held liable for the acts, either of omission or
     commission, of any other Party hereto.

17.2 Choice of Law. THIS AGREEMENT, AND THE OTHER MATTERS ARISING DIRECTLY OR
     INDIRECTLY OUT OF THIS AGREEMENT, SHALL BE GOVERNED BY AND CONSTRUED IN
     ACCORDANCE WITH THE GENERAL MARITIME LAW OF THE UNITED STATES TO THE EXTENT
     APPLICABLE, OTHERWISE BY THE LAWS OF THE STATE OF LOUISIANA WITHOUT REGARD
     TO CONFLICTS OF LAWS PRINCIPLES THAT MIGHT OTHERWISE APPLY THE LAWS OF
     ANOTHER STATE OR JURISDICTION.

17.3 Authority. If any Party is a legal entity, including, but not limited to,
     an association, corporation, joint venture, limited partnership,
     partnership or trust, such Party represents to the other Party that the
     execution and delivery of this Agreement and the completion of the
     transactions contemplated herein have been duly authorized by all necessary
     corporate proceedings or have received all necessary management approvals.

17.4 Conflict. Except as expressly provided in this Agreement, to the extent of
     any conflict between the provisions of this Agreement and the provisions of
     the Operating Agreement, the provisions of this Agreement shall supersede
     and control to the extent of such conflict.

17.5 Section Headings. The section headings used herein are for convenience only
     and shall not be construed as having any substantive significance or as
     indicating that all of the provisions of this Agreement relating to any
     particular topic are to be found in any particular section.

17.6 Entire Agreement. This Agreement, together with the instruments referenced
     herein and the attachments hereto, embody the entire agreement between the
     Parties with regard to the subject matter hereof, and supersedes all other
     prior or contemporaneous agreements (other than the Operating Agreement),
     arrangements, proposals, representations, negotiations, communications and
     understandings, whether oral or written, relating to the subject matter
     hereof.

                                       20.

<PAGE>

17.7   Exhibits and Attachments. All exhibits, attachments and the like
       contained herein or attached hereto are integrally related to this
       Agreement, and are hereby made a part of this Agreement for all purposes.
       To the extent of any ambiguity, inconsistency or conflict between the
       body of this Agreement and any of the exhibits, attachments and the like
       attached hereto, the terms of this Agreement shall prevail over the
       exhibits and attachments, to the extent of such conflict.

17.8   Amendment, Modification and Waiver. This Agreement may be supplemented,
       altered, amended, modified or revoked in writing and any of the terms,
       covenants, representations, warranties or conditions hereof may be
       waived, only by a written instrument executed by all of the Parties or,
       in the case of a waiver, by or on behalf of the Party waiving compliance.
       The failure of any Party at any time or times to require performance of
       any provisions hereof shall in no manner affect the right at a later time
       to enforce the same. No waiver by any Party of any condition, or of any
       breach of any term, covenant, representation or warranty contained in
       this Agreement, in any one or more instances, shall be deemed to be or
       construed as a further or continuing waiver of any such condition or
       breach or a waiver of any other condition or of any breach of any other
       term, covenant, representation or warranty.

17.9   Further Assurances. The Parties will execute and deliver or use
       reasonable efforts to cause to be executed and delivered such other
       instruments and take such other actions as the Parties reasonably may
       request to more effectively accomplish the purposes of this Agreement.

17.10  Successors and Assigns. This Agreement shall be binding upon and inure to
       the benefit of the Parties and their respective heirs, successors,
       representatives and permitted assigns and shall constitute a covenant
       running with the Contract Area.

17.11  Notices. The Parties agree that any notices, communications or documents
       that either of them desire or that may be required to be delivered to the
       other Party shall be sent to the Parties at the following respective
       addresses stated for each:

       BP America Production Company              Ridgewood Energy Corporation
       200 Westlake Park Blvd.                    11700 Old Katy Road, Suite 280
       Houston, TX 77079                          Houston, TX 77079
       Attn: James A. Webb                        Attn: W. Greg Tabor
       Phone:    281-366-5393                     Phone:   281-293-8449
       Fax:   281-366-7613                        Fax:  281-293-7705

       All notices and responses thereto shall be in writing and delivered in
       person or by telephone followed by United States mail, telex, telegraph,
       telecopier (facsimile) or cable; however, if the drilling rig is on
       location and standby charges are accumulating, such notices and responses
       shall be given by telephone and immediately confirmed in writing. Notices
       and responses shall be deemed given only when received by the Party to
       whom

                                       21.

<PAGE>

       such notice or response is directed, except that any notice or response
       by certified United States mail or equivalent, telegraph, or cable
       properly addressed, pursuant to this Article 17.11, and with all postage
       and charges prepaid shall be deemed given seventy-two (72) hours after
       such notice is deposited in the mail inclusive of Saturdays, Sundays, and
       federal holidays, or twenty-four (24) hours after such notice or response
       is sent by telecopier (facsimile), receipt confirmed and verified by
       telephone, or filed with an operating telegraph or cable company for
       immediate transmission inclusive of Saturdays, Sundays, and federal
       holidays. Either Party may change its address for notice by notice to the
       other Party.

17.12  Confidentiality, News Releases and Disclosures. This Agreement shall be
       kept strictly confidential, and no press release or other public
       announcement or disclosure regarding this Agreement or the Leases shall
       be made by either Party without the prior written consent of the other
       Party. However, either Party may make releases or public announcements
       which are required in order to comply with applicable laws; provided, the
       releasing, announcing and/or disclosing Party first gives the other Party
       adequate notice and time for review of and comment on such release,
       announcement or disclosure before it is made. BP acknowledges that
       Ridgewood may desire to disclose certain terms of this Agreement in its
       marketing brochures, drilling fund prospectus' or company website and BP
       agrees to give appropriate attention to Ridgewood's consent requests with
       respect to such disclosures, but such consent may be given or refused in
       BP's sole discretion. Notwithstanding anything herein to the contrary,
       the Parties acknowledge and agree they shall always be subject to Article
       7.3 (Confidentiality) of the Operating Agreement even prior to
       Ridgewood's earning an interest pursuant hereto and nothing in this
       Agreement shall be considered an exception to or waiver of such
       confidentiality obligations.

17.13  Severability. If any provision of this Agreement is held to be illegal,
       invalid or unenforceable under present or future laws in effect during
       the term hereof, such provision shall be fully severable; this Agreement
       shall be modified, construed and enforced as if such illegal, invalid or
       unenforceable provision had never comprised a part hereof and the
       remaining provisions hereof shall remain in full force and effect and
       shall not be affected by the illegal, invalid or unenforceable provision
       or by its severance therefrom. If any provision of this Agreement is so
       broad as to be unenforceable, each provision shall be interpreted to be
       only so broad as is enforceable. A bankruptcy or similar trustee must
       accept or, to the extent permitted by law, reject this Agreement in its
       entirety.

17.14  Jointly Drafted Agreement. The Parties acknowledge that they have had an
       adequate opportunity to review each and every provision contained in this
       Agreement and to submit the same to legal counsel for review and comment.
       Based on the foregoing, the Parties agree that the drafting of this
       Agreement was a joint effort, and the rule of

                                       22.

<PAGE>

       construction that a contract be construed against the drafter, if any,
       shall not be applied in the interpretation or construction of this
       Agreement.

17.15  Counterparts. This Agreement may be executed in counterparts and each
       such counterpart shall have the same force and effect as the original
       hereof; provided, however, that none of said counterparts shall be
       effective until all the Parties hereto have executed a counterpart
       hereof.

EXECUTED as of the 14th day of April, 2005, but effective as of the date first
above written.

Witnesses:                                      BP America Production Company

[SIGNATURE ILLEGIBLE]                           By. /s/ Johanna Meinhardt-Sharp
--------------------------                          ---------------------------
                                                        Johanna Meinhardt-Sharp
[SIGNATURE ILLEGIBLE]                           Its:    Attorney-in-Fact
--------------------------

Witnesses:                                     Ridgewood Energy Corporation

[SIGNATURE ILLEGIBLE]                          By: /s/ W. Greg Tabor
--------------------------                         ----------------------------
                                                       W. Greg Tabor
[SIGNATURE ILLEGIBLE]                          Its:    Executive Vice President
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