AMENDMENT TO SECURITY AGREEMENT

THIS AMENDMENT TO SECURITY AGREEMENT (the “Amendment”) is made this 1st day of
October, 2009, by and among SONTERRA RESOURCES, INC., a Delaware corporation
(the “Company”), NORTH TEXAS DRILLING SERVICES, INC., a Texas corporation
(“North Texas”), SONTERRA OPERATING, INC., a Delaware corporation (“Operating”),
VELOCITY ENERGY LIMITED LLC, a Texas limited liability company (“Limited”),
VELOCITY ENERGY INC., a Delaware corporation (“Velocity”), VELOCITY ENERGY
OFFSHORE LP, a Delaware limited partnership (“Offshore”), and VELOCITY ENERGY
PARTNERS LP, a Delaware limited partnership (“Onshore”) (with the Company, North
Texas, Operating, Limited, Velocity, Offshore and Onshore being sometimes
referred to individually as a “Debtor” and, collectively, as the “Debtors”), and
SUMMERLINE ASSET MANAGEMENT, LLC, a Delaware limited liability company, in its
capacity as Collateral Agent (as set forth in Section 5.11 of the Security
Agreement (as defined below), together with its successors and assigns in such
capacity, the “Secured Party”).

WHEREAS, Debtors and Secured Party are parties to that certain Security
Agreement dated November 13, 2008 (as amended, restated, supplemented, or
otherwise modified from time to time, the “Security Agreement”), pursuant to
which Onshore, among others, granted a security interest in certain collateral
as more specifically set forth therein (the “Collateral” as that term is defined
in the Security Agreement); and

WHEREAS, the Secured Party has agreed to subordinate its interest in the
Collateral owned by Onshore to the extent that such Collateral is located on or
derived from any Hydrocarbon Property as defined in that certain Mortgage, Deed
of Trust, Assignment of Production, Security Agreement, Fixture Filing and
Financing Statement by Velocity Energy Partners LP, a Delaware Limited Liability
Company, to R. Ford Francis, as Trustee (the “Trustee”) for the benefit of
Classic Oil & Gas Resources, Inc. (“Classic Oil”), a Kentucky Corporation, dated
September 29, 2009 (the “Classic Oil Mortgage”), and that the Trustee holds a
perfected security interest in the Hydrocarbon Property for the benefit of
Classic Oil.

NOW, THEREFORE, for Ten Dollars ($10.00), and other good and valuable
consideration, the sufficiency and receipt of which are hereby acknowledged,
Debtors and Secured Party agree to amend the Security Agreement as follows.

 
1.
Subordination of Security Interest.  Secured Party hereby subordinates its
security interest in the Collateral owned by Onshore in favor of the Trustee for
the benefit of Classic Oil to the extent that such Collateral is located on or
derived from any Hydrocarbon Property (as defined in the Classic Oil Mortgage)
and that the Trustee holds a perfected security interest in the Hydrocarbon
Property for the benefit of Classic Oil.

 
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2.
Third Party Beneficiaries; No Amendment. Secured Party and Onshore agree that
the Trustee and Classic Oil are intended to be third-party beneficiaries of this
Amendment and that Secured Party and Onshore shall not amend the Security
Agreement so as to negate or diminish the subordination to the Classic Oil
Mortgage set forth in Section 1 above for so long as any Indebtedness (as
defined in the Classic Oil Mortgage) remains unpaid.

 
3.
No Other Changes.  In all other respects, the Security Agreement remains
unchanged and in force.

IN WITNESS WHEREOF, the parties have executed this instrument on this the 1st
day of October, 2009.

SONTERRA RESOURCES, INC., a Delaware corporation
 
By:
/s/ D. E. Vandenberg
Name:
   D.E. Vandenberg
Title:
   President
   
NORTH TEXAS DRILLING SERVICES, INC., a Texas corporation
 
By:
/s/ D. E. Vandenberg
Name:
   D.E. Vandenberg
Title:
   President
   
SONTERRA OPERATING, INC., a Delaware corporation
 
By:
/s/ D. E. Vandenberg 
Name:
   D.E. Vandenberg
Title:
   President
   
VELOCITY ENERGY LIMITED LLC, a Texas limited liability company
 
By:
/s/ D. E. Vandenberg
Name:
   D.E. Vandenberg
Title:
   President

 
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VELOCITY ENERGY INC., a Delaware corporation
 
By:
/s/ D. E. Vandenberg
Name:
   D.E. Vandenberg
Title:
   President
   
VELOCITY ENERGY OFFSHORE LP, a Delaware limited partnership
 
By:
/s/ D. E. Vandenberg
Name:
   D.E. Vandenberg
Title:
   President
   
VELOCITY ENERGY PARTNERS LP, a Delaware limited partnership
 
By:
/s/ D. E. Vandenberg
Name:
   D.E. Vandenberg
Title:
   President

 
SUMMERLINE ASSET MANAGEMENT, LLC
   
BY:
Name:
  Robert J. Brantman
Title:
  Co-Managing Member

 
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