Form 4 Filed by Seldin Peter K on April 28, 2008

This form 4 (insider trading filing) was submitted to the Securities and Exchange Commission (SEC) by insider Seldin Peter K on April 28, 2008. The CIK number of this insider is 898406. At the time of this reporting, Seldin Peter K is the 10% Owner of Gas Corp . See all insider stock transactions reported by Seldin Peter K and all stock buys, sales, and option exercises made by insiders at Gas Corp . The stock ticker symbol of Gas Corp is ATPG.

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Expires: February 28, 2011 Estimated average burden hours per response 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* CENTENNIAL ENERGY PARTNERS LLC (Last) (First) (Middle) 575 LEXINGTON AVENUE 33RD FLOOR (Street) NEW YORK NY 10022 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol ATP OIL & GAS CORP [ ATPG ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 04/22/2008
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	04/22/2008		P		33,000	A	$29.7137	4,426,562	I ( 1 )	See Footnote
Common Stock	04/23/2008		P		54,500	A	$28.8364	4,481,062	I ( 1 )	See Footnote

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person* CENTENNIAL ENERGY PARTNERS LLC (Last) (First) (Middle) 575 LEXINGTON AVENUE 33RD FLOOR (Street) NEW YORK NY 10022 (City) (State) (Zip)

1. Name and Address of Reporting Person* SELDIN PETER K (Last) (First) (Middle) 575 LEXINGTON AVENUE 33RD FLOOR (Street) NEW YORK NY 10022 (City) (State) (Zip)

Explanation of Responses:

1. These securities are directly owned by certain private investment vehicles to which Centennial Energy Partners, L.L.C. serves as general partner and they may be deemed to be beneficially owned by Centennial Energy Partners, L.L.C. and Peter K. Seldin. Peter K. Seldin is the Managing Member of Centennial Energy Partners, L.L.C. Each Reporting Person disclaims beneficial ownership of the reported securities except to the extent of his or its pecuniary interest therein, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of the securities for purposes of Section 16 of the Securities Exchange Act of 1034, as amended, or for any other person.

	Centennial Energy Partners, L.L.C., By: /s/ Peter K. Seldin, Managing Member	04/28/2008
	Peter K. Seldin	04/28/2008
	** Signature of Reporting Person	Date
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