Document:

<PAGE>

                                                                   Exhibit 10.11

                                OMNIBUS AGREEMENT

         THIS OMNIBUS AGREEMENT ("Agreement") is entered into on, and effective
as of, the Closing Date, by and among Atlas Pipeline Holdings, L.P.
("Holdings"), a Delaware limited partnership, Atlas Pipeline Holdings GP, LLC, a
Delaware limited liability company ("Holdings GP"), and Atlas Pipeline Partners,
L.P., a Delaware limited partnership (the "MLP").

         In consideration of the premises and the covenants, conditions, and
agreements contained herein, and for other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the parties hereto
hereby agree as follows:

                                    ARTICLE I
                                   DEFINITIONS

         Section 1.1 Definitions.

         (a) Capitalized terms used herein but not defined herein shall have the
meanings given them in the MLP Agreement.

         (b) As used in this Agreement, the following terms shall have the
respective meanings set forth below:

                  "Closing Date" shall mean the closing of the initial public
         offering of common units representing limited partner interests in
         Atlas Pipeline Holdings, L.P.

                  "Holdings Conflicts Committee" shall mean the "Conflicts
         Committee" as defined in the Amended and Restated Agreement of Limited
         Partnership of Holdings.

                  "Holdings Entities" shall mean Holdings and Holdings GP.

                  "MLP Agreement" shall mean the Second Amended and Restated
         Agreement of Limited Partnership of the MLP, dated as of March 9, 2004,
         as the same may be amended.

                  "MLP Conflicts Committee" shall mean the "Conflicts Committee"
         as defined in the MLP Agreement.

                  "MLP Entities" shall mean the MLP and any of its subsidiaries.

                  "MLP Group" shall mean the MLP and all of its subsidiaries.

<PAGE>

                                   ARTICLE II
                             BUSINESS OPPORTUNITIES

         Section 2.1 Restricted Businesses. For as long as Holdings or any of
its subsidiaries is the general partner of the MLP, if a Holdings Entity is
presented with an opportunity to pursue, purchase or invest in any business
opportunity (a "Business Opportunity") with respect to a business activity in
which the MLP is engaged as of the Closing Date (a "Restricted Business"), the
Holdings Entity shall give prompt written notice to the MLP of the Business
Opportunity. Such notice shall set forth all information available to the
Holdings Entity including, but not limited to, the identity of the Business
Opportunity and its seller, the proposed price, all written information about
the Business Opportunity provided to the Holdings Entity by and on behalf of the
seller as well as any information or analyses compiled by the Holdings Entity
from other sources (such information referred to collectively herein as
"Business Opportunity Information"). The Holdings Entity shall continue to
provide to the MLP promptly any and all Business Opportunity Information
subsequently received. Within a time period specified by the Holdings Entity's
notice, which shall be a reasonable time under the circumstances, the MLP shall
advise the Holdings Entity in writing whether MLP wishes to acquire the Business
Opportunity. If the MLP advises the Holdings Entity of its intent to acquire the
Business Opportunity, the Holdings Entities shall refrain from making an offer
for the Business Opportunity except as permitted hereunder. If the MLP (i)
advises the Holdings Entity that (with the approval of the MLP Conflicts
Committee) it does not intend to acquire the Business Opportunity, (ii) advises
the Holdings Entity of its intent to acquire the Business Opportunity but does
not complete the acquisition within a reasonable time after the MLP's notice of
its intent to the Holdings Entity or (iii) fails to timely advise the Holdings
Entity of its intent, any of the Holdings Entities shall be free to acquire the
Business Opportunity.

         Section 2.2 Scope of Restricted Business Prohibition. Except as
provided in this Article II and the Amended and Restated Agreement of Limited
Partnership of Holdings, as the same may be amended from time to time, each
Holdings Entity shall be free to engage in any business activity whatsoever,
including those that may be in direct competition with any MLP Entity.

         Section 2.3 Enforcement. The Holdings Entities agree and acknowledge
that the MLP Group does not have an adequate remedy at law for the breach by the
Holdings Entities of the covenants and agreements set forth in this Article II,
and that any breach by the Holdings Entities of the covenants and agreements set
forth in Article II would result in irreparable injury to the MLP Group. The
Holdings Entities further agree and acknowledge that any member of the MLP Group
may, in addition to the other remedies which may be available to the MLP Group
hereunder or under applicable law, file a suit in equity to enjoin the Holdings
Entities from such breach, and the Holdings Entities consent to the issuance of
injunctive relief hereunder.

                                  ARTICLE III
                                  MISCELLANEOUS

         Section 3.1 Choice of Law; Submission to Jurisdiction. This Agreement
shall be subject to and governed by the laws of the State of Delaware, excluding
any conflicts-of-law rule or principle that might refer the construction or
interpretation of this Agreement to the laws of another state.

         Section 3.2 Notice. All notices or requests or consents provided for or
permitted to be given pursuant to this Agreement must be in writing and must be
given by depositing same in the United States mail, addressed to the Person to
be notified, postpaid, and registered or certified with return receipt requested
or by delivering such notice in person or by telecopier or telegram to such
party. Notice given by personal delivery or mail shall be effective upon actual
receipt. Notice given by telegram or telecopier shall be effective upon actual
receipt if received during the recipient's normal business hours, or at the
beginning of the recipient's next business day after receipt if not received
during the recipient's normal business hours. All notices to be sent to a party
pursuant to this Agreement shall be sent to or made at the address set forth
below such party's signature to this Agreement, or at such other address as such
party may stipulate to the other parties in the manner provided in this Section
3.2.

                                       2

<PAGE>

         Section 3.3 Entire Agreement; Supersedure. This Agreement constitutes
the entire agreement of the parties relating to the matters contained herein,
superseding all prior contracts or agreements, whether oral or written, relating
to the matters contained herein.

         Section 3.4 Effect of Waiver or Consent. No waiver or consent, express
or implied, by any party to or of any breach or default by any Person in the
performance by such Person of its obligations hereunder shall be deemed or
construed to be a consent or waiver to or of any other breach or default in the
performance by such Person of the same or any other obligations of such Person
hereunder. Failure on the part of a party to complain of any act of any Person
or to declare any Person in default, irrespective of how long such failure
continues, shall not constitute a waiver by such party of its rights hereunder
until the applicable statute of limitations period has run.

         Section 3.5 Amendment or Modification. This Agreement may be amended or
modified from time to time only by the written agreement of all the parties
hereto; provided, however, that (i) the MLP may not, without the prior approval
of the MLP Conflicts Committee, agree to any amendment or modification of this
Agreement that, in the reasonable discretion of Atlas Pipeline Partners GP, LLC,
will adversely affect the holders of MLP common units; and (ii) Holdings may
not, without the prior approval of the Holdings Conflicts Committee, agree to
any amendment or modification of this Agreement that, in the reasonable
discretion of Holdings, will adversely affect the holders of Holdings common
units. Each such instrument shall be reduced to writing and shall be designated
on its face an "Amendment" or an "Addendum" to this Agreement.

         Section 3.6 Assignment. No Party shall have the right to assign its
rights or obligations under this Agreement without the consent of the other
parties hereto.

         Section 3.7 Counterparts. This Agreement may be executed in any number
of counterparts with the same effect as if all Parties had signed the same
document. All counterparts shall be construed together and shall constitute one
and the same instrument.

         Section 3.8 Severability. If any provision of this agreement or the
application thereof to any person or circumstance shall be held invalid or
unenforceable to any extent, the remainder of this agreement and the application
of such provision to other persons or circumstances shall not be affected
thereby and shall be enforced to the greatest extent permitted by law.

                                       3
<PAGE>

         Section 3.9 Gender, Parts, Articles and Sections. Whenever the context
requires, the gender of all words used in this Agreement shall include the
masculine, feminine and neuter, and the number of all words shall include the
singular and plural. All references to Article numbers and Section numbers refer
to Parts, Articles and Sections of this Agreement, unless the context otherwise
requires.

         Section 3.10 Further Assurances. In connection with this Agreement and
all transactions contemplated by this Agreement, each Party hereto agrees to
execute and deliver such additional documents and instruments and to perform
such additional acts as may be necessary or appropriate to effectuate, carry out
and perform all of the terms, provisions and conditions of this Agreement and
all such transactions.

         Section 3.11 Laws and Regulations. Notwithstanding any provision of
this Agreement to the contrary, no Party hereto shall be required to take any
act, or fail to take any act, under this Agreement if the effect thereof would
be to cause such Party to be in violation of any applicable law, statute, rule
or regulation.

         Section 3.12 Negation of Rights of Limited Partners, Assignees, and
Third Parties. The provisions of this Agreement are enforceable solely by the
parties to this Agreement, and no limited partner, assignee or other Person
shall have the right, separate and apart from the MLP or Holdings, to enforce
any provision of this Agreement or to compel any Party to this Agreement to
comply with the terms of this Agreement.

                                       4
<PAGE>

         IN WITNESS WHEREOF, the parties have executed this Agreement on, and
effective as of, the Closing Date.

                                   ATLAS PIPELINE HOLDINGS, L.P.

                                   By:    ATLAS PIPELINE HOLDINGS GP, LLC, its
                                          general partner

                                   By:    ____________________________________
                                   Name:
                                   Title:

                                   Address for Notice:  311 Rouser Road
                                                        Moon Township, PA 15108
                                                        Attn: Lisa Washington

                                   Telecopy Number:     (215-761-0457)

                                   ATLAS PIPELINE HOLDINGS GP, LLC

                                   By:    ____________________________________
                                   Name:
                                   Title:

                                   Address for Notice:
                                                        311 Rouser Road
                                                        Moon Township, PA 15108
                                                        Attn: Lisa Washington

                                   Telecopy Number:     (215-761-0457)

                                     A-1
<PAGE>

                                   ATLAS PIPELINE PARTNERS, L.P.

                                   By:    ATLAS PIPELINE PARTNERS GP, LLC, its
                                          general partner

                                   By:    ____________________________________
                                   Name:
                                   Title:

                                   Address for Notice:  311 Rouser Road
                                                        Moon Township, PA 15108
                                                        Attn: Lisa Washington

                                   Telecopy Number:     (215-761-0457)

                                       A-2<PAGE>

                                                                   Exhibit 10.12

                             [SPECIMEN CERFTIFICATE]

                             [FRONT OF CERTIFICATE]

                       CERTIFICATE EVIDENCING COMMON UNITS
                  REPRESENTING LIMITD PARTNERSHIP INTERESTS IN

NUMBER                                                             COMMON UNITS

THIS CERTIFICATE IS TRANSFERABLE IN                             CUSIP
NEW YORK, N.Y.                                                  SEE REVERSE FOR
                                                            CERTAIN DEFINITIONS

                          ATLAS PIPELINE HOLDINGS, L.P.
             A LIMITED PARTNERSHIP FORMED UNDER THE LAWS OF DELAWARE

     In accordance with Section 4.1 of the Amended and Restated Agreement of
Limited Partnership of Atlas Pipeline Holdings, L.P., as amended, supplemented
or restated from time to time (the "Partnership Agreement"), Atlas Pipeline
Holdings, L.P., a Delaware limited partnership (the "Partnership"),

     hereby certifies that

     (the "Holder") is the registered owner of                      Common Units

representing limited partner interests in the Partnership (the "Common Units")
transferable on the books of the Partnership, in person or by duly authorized
attorney, upon surrender of this Certificate properly endorsed and accompanied
by a properly executed application for the transfer of the Common Units
represented by this Certificate. The rights, preferences and limitations of the
Common Units are set forth in, and this Certificate and the Common Units
represented hereby are issued and shall in all respects be subject to the terms
and provisions of, the Partnership Agreement. Copies of the Partnership
Agreement are on file at, and will be furnished without charge on delivery of
written request to the Partnership at, the principal office of the Partnership
located at 311 Rouser Road, Moon Township, PA 15108. Capitalized terms used
herein but not defined herein shall have the meanings given them in the
Partnership Agreement.

     The Holder, by accepting this Certificate, is deemed to have (i) requested
admission as, and agreed to become, a Limited Partner and to have agreed to
comply with and be bound by and to have executed the Partnership Agreement, (ii)
represented and warranted that the Holder has all right, power and authority
and, if an individual, the capacity necessary to enter into the Partnership
Agreement, (iii) granted the powers of attorney provided for in the Partnership
Agreement and (iv) made the waivers and given the consents and approvals
contained in the Partnership Agreement.

     THE HOLDER OF THIS SECURITY ACKNOWLEDGES FOR THE BENEFIT OF ATLAS PIPELINE
HOLDINGS, L.P. THAT THIS SECURITY MAY NOT BE SOLD, OFFERED, RESOLD, PLEDGED OR
OTHERWISE TRANSFERRED IF SUCH TRANSFER WOULD (A) VIOLATE THE THEN APPLICABLE
FEDERAL OR STATE SECURITIES LAWS OR RULES AND REGULATIONS OF THE SECURITIES AND
EXCHANGE COMMISSION, ANY STATE SECURITIES COMMISSION OR ANY OTHER GOVERNMENTAL
AUTHORITY WITH JURISDICTION OVER SUCH TRANSFER, (B) TERMINATE THE EXISTENCE OR
QUALIFICATION OF ATLAS PIPELINE HOLDINGS, L.P. UNDER THE LAWS OF THE STATE OF
DELAWARE, OR (C) CAUSE ATLAS PIPELINE HOLDINGS, L.P. TO BE TREATED AS AN
ASSOCIATION TAXABLE AS A CORPORATION OR OTHERWISE TO BE TAXED AS AN ENTITY FOR
FEDERAL INCOME TAX PURPOSES (TO THE EXTENT NOT ALREADY SO TREATED OR TAXED).
ATLAS PIPELINE HOLDINGS GP, LLC, THE GENERAL PARTNER OF ATLAS PIPELINE HOLDINGS,
L.P., MAY IMPOSE ADDITIONAL RESTRICTIONS ON THE TRANSFER OF THIS SECURITY IF IT
RECEIVES AN OPINION OF COUNSEL THAT SUCH RESTRICTIONS ARE NECESSARY TO AVOID A
SIGNIFICANT RISK OF ATLAS PIPELINE HOLDINGS, L.P. BECOMING TAXABLE AS A
CORPORATION OR OTHERWISE BECOMING TAXABLE AS AN ENTITY FOR FEDERAL INCOME TAX
PURPOSES. THE RESTRICTIONS SET FORTH ABOVE SHALL NOT PRECLUDE THE SETTLEMENT OF
ANY TRANSACTIONS INVOLVING THIS SECURITY ENTERED INTO THROUGH THE FACILITIES OF
ANY NATIONAL SECURITIES EXCHANGE ON WHICH THIS SECURITY IS LISTED OR ADMITTED TO
TRADING.

<PAGE>

     This Certificate shall not be valid for any purpose unless it has been
countersigned and registered by the Transfer Agent and Registrar.

Dated:                                 Atlas Pipeline Holdings, L.P.

                                       By:  Atlas Pipeline Holdings GP, LLC,
                                            its General Partner

                                       By:  ____________________________________
                                            President

                                       By:  ____________________________________
                                            Secretary
Countersigned and Registered by:

     American Stock Transfer & Trust Company,
     as Transfer Agent and Registrar

By:  ________________________________________
     Authorized Signature

<PAGE>

                            [REVERSE OF CERTIFICATE]

                                  ABBREVIATIONS

The following abbreviations, when used in the inscription on the face of this
Certificate, shall be construed as follows according to applicable laws or
regulations:
<TABLE>
<S>         <C>                                         <C>                       <C>
TEN COM     as tenants in common                        UNIF GIFT/TRANSFERS       _____ Custodian _______
                                                        MIN ACT
TEN ENT     as tenants by the entireties                                          (Cust)               (Minor)
JT TEN      as joint tenants with right of                                        under Uniform Gifts/Transfers
            survivorship and not as tenants in common                             to CD Minors Act
                                                                                  _______________
                                                                                     (State)
</TABLE>

   Additional abbreviations, though not in the above list, may also be used.

                           ASSIGNMENT OF COMMON UNITS
                                       IN
                          ATLAS PIPELINE HOLDINGS, L.P.

     FOR VALUE RECEIVED, ________________ hereby assigns, conveys, sells and
transfers unto __________

<TABLE>
<S>                                                                        <C>
______________________________________________________________________     ________________________________________________________
(Please insert Social Security or other identifying number of Assignee)    (Please print or typewrite name and address of Assignee)
</TABLE>

______ Common Units representing limited partner interests evidenced by this
Certificate, subject to the Partnership Agreement, and does hereby irrevocably
constitute and appoint _____________ as its attorney-in-fact with full power of
substitution to transfer the same on the books of Atlas Pipeline Holdings, L.P.

<TABLE>
<S>                                                  <C>
Date:  ________________                              NOTE:  The signature to any endorsement hereon must
                                                     correspond with the name as written upon the face of this
                                                     Certificate in every particular, without alteration,
                                                     enlargement or change.

THE SIGNATURE(S) MUST BE GUARANTEED                                     ------------------------------------------------
                                                                                          (Signature)
BY AN ELIGIBLE GUARANTOR INSTITUTION (BANKS, STOCKBROKERS, SAVINGS AND LOAN
ASSOCIATIONS AND CREDIT UNIONS WITH MEMBERSHIP IN AN APPROVED SIGNATURE
GUARANTEE MEDALLION PROGRAM), PURSUANT TO S.E.C.
RULE 17AD-15
                                                                        ------------------------------------------------
                                                                                          (Signature)
</TABLE>

________________________________
SIGNATURE(S) GUARANTEED

No transfer of the Common Units evidenced hereby will be registered on the books
of the Partnership, unless the Certificate evidencing the Units to be
transferred is surrendered for registration or transfer and an Application for
Transfer of Common Units has been properly completed and executed by a
transferee either (a) on the form set forth below or (b) on a separate
application that the Partnership will furnish on request without charge. A
transferor of the Common Units shall have no duty to the transferee with respect
to execution of the Application for Transfer of the Common Units in order for
such transferee to obtain registration of the transfer of the Common Units.

<PAGE>

                    APPLICATION FOR TRANSFER OF COMMON UNITS

     The undersigned ("Assignee") hereby applies for transfer to the name of the
Assignee of the Common Units evidenced hereby.

     The Assignee (a) requests admission as a Substituted Limited Partner and
agrees to comply with and be bound by, and hereby executes, the Amended and
Restated Agreement of Limited Partnership of Atlas Pipeline Holdings, L.P. (the
"Partnership"), as amended, supplemented or restated to the date hereof (the
"Partnership Agreement"), (b) represents and warrants that the Assignee has all
right, power and authority and, if an individual, the capacity necessary to
enter into the Partnership Agreement, (c) appoints the General Partner of the
Partnership and, if a Liquidator shall be appointed, the Liquidator of the
Partnership as the Assignee's attorney-in-fact to execute, swear to, acknowledge
and file any document, including, without limitation, the Partnership Agreement
and any amendment thereto and the Certificate of Limited Partnership of the
Partnership and any amendment thereto, necessary or appropriate for the
Assignee's admission as a Limited Partner and as a party to the Partnership
Agreement, (d) gives the powers of attorney provided for in the Partnership
Agreement, and (e) makes the waivers and gives the consents and approvals
contained in the Partnership Agreement. Capitalized terms not defined herein
have the meanings assigned to such terms in the Partnership Agreement.

Date: _________________

<TABLE>
<S>                                                                    <C>
_________________________________________________________              __________________________________________
(Social Security or other identifying number of Assignee)              (Signature of Assignee)

_____________________________________________                          __________________________________________
(Purchase Price including commission, if any)                          (Name and Address of Assignee)
</TABLE>

Type of Entity (check one):
     [___] Individual            [___] Partnership         [___] Corporation
     [___] Trust [___]           Other (specify)________________________________

Nationality (check one):
     [___] U.S. Citizen, Resident or Domestic Entity
     [___] Foreign Corporation              [___] Non-resident Alien

     If the U.S. Citizen, Resident or Domestic Entity box is checked, the
following certification must be completed.

     Under Section 1445(e) of the Internal Revenue Code of 1986, as amended (the
"Code"), the Partnership must withhold tax with respect to certain transfers of
property if a holder of an interest in the Partnership is a foreign person.

     To inform the Partnership that no withholding is required with respect to
the undersigned interestholder's interest in it, the undersigned hereby
certifies the following (or, if applicable, certifies the following on behalf of
the interestholder).

Complete Either A or B:

A.   Individual Interestholder

     1. I am not a non-resident alien for purposes of U.S. income taxation.

     2. My U.S. taxpayer identification number (Social Security Number) is
__________________.

     3. My home address is
_________________________________________________________.

B.   Partnership, Corporation or Other Interestholder

     1. _________________________________________________________(name of
Interestholder) is not a foreign corporation, foreign partnership, foreign trust
or foreign estate (as those terms are defined in the Code and Treasury
Regulations).

     2. The interestholder's U.S. employer identification number is
_________________________.

     3. The interestholder's office address and place of incorporation (if
applicable) is ______________________.

     The interestholder agrees to notify the Partnership within sixty (60) days
of the date the interestholder becomes a foreign person.

     The interestholder understands that this certificate may be disclosed to
the Internal Revenue Service by the Partnership and that any false statement
contained herein could be punishable by fine, imprisonment or both.

<PAGE>

     Under penalties of perjury, I declare that I have examined this
certification and to the best of my knowledge and belief it is true, correct and
complete and, if applicable, I further declare that I have authority to sign
this document on behalf of

           ----------------------------------------------------------
                             Name of Interestholder

           ----------------------------------------------------------
                               Signature and Date

           ----------------------------------------------------------
                              Title (if applicable)
           ----------------------------------------------------------

     Note: If the Assignee is a broker, dealer, bank, trust company, clearing
corporation, other nominee holder or an agent of any of the foregoing, and is
holding for the account of any other person, this application should be
completed by an officer thereof or, in the case of a broker or dealer, by a
registered representative who is a member of a registered national securities
exchange or a member of the National Association of Securities Dealers, Inc.,
or, in the case of any other nominee holder, a person performing a similar
function. If the Assignee is a broker, dealer, bank, trust company, clearing
corporation, other nominee owner or an agent of any of the foregoing, the above
certification as to any person for whom the Assignee will hold the Units shall
be made to the best of the Assignee's knowledge.

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00105-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00105-of-00352.parquet"}]]