UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

For the Quarterly Period Ended March 31,June 30, 2012

Or

For the Transition Period Fromto

Commission File Number 0-7406

PrimeEnergy Corporation

(Exact name of registrant as specified in its charter)

One Landmark Square, Stamford, Connecticut 069019821 Katy Freeway, Houston, Texas 77024

(Address of principal executive offices)

(203) 358-5700(713) 735-0000

(Registrant’s telephone number, including area code)

One Landmark Square, Stamford, Connecticut 06901

(Former name, former address and former fiscal year, if changed since last report)

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15 (d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filings required for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  x    No  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer”, “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes  ¨    No  x

The number of shares outstanding of each class of the Registrant’s Common Stock as of May 8,August 2, 2012 was: Common Stock, $0.10 par value 2,628,9682,621,564 shares.

PrimeEnergy Corporation

Index to Form 10-Q

March 31,June 30, 2012

PART I—FINANCIAL INFORMATION

PRIMEENERGY CORPORATIONItem 1.   FINANCIAL STATEMENTS

PrimeEnergy Corporation

CONDENSED CONSOLIDATED BALANCE SHEETS– Unaudited

(Thousands of dollars)

The accompanying Notes are an integral part of these Condensed Consolidated Financial Statements

PrimeEnergy Corporation

CONDENSED CONSOLIDATED STATEMENTSOF OPERATIONS – Unaudited

(Thousands of dollars, except per share amounts)

The accompanying Notes are an integral part of these Condensed Consolidated Financial Statements

PRIMEENERGY CORPORATIONPrimeEnergy Corporation

CONDENSED CONSOLIDATED STATEMENTSOF OPERATIONS– Unaudited

Three Months Ended March 31, 2012 and 2011

(Thousands of dollars, except per share amounts)

The accompanying Notes are an integral part of these Condensed Consolidated Financial Statements

PRIMEENERGY CORPORATION

CONDENSED CONSOLIDATED STATEMENTOF STOCKHOLDERS’ EQUITY– Unaudited

ThreeSix Months Ended March 31,June 30, 2012

(Thousands of dollars)

The accompanying Notes are an integral part of these Condensed Consolidated Financial StatementsStatement

PRIMEENERGY CORPORATIONPrimeEnergy Corporation

CONDENSED CONSOLIDATED STATEMENTSOF CASH FLOWS –– Unaudited

ThreeSix Months Ended March 31,June 30, 2012 and 2011

(Thousands of dollars)

The accompanying Notes are an integral part of these Condensed Consolidated Financial StatementsStatement

PRIMEENERGY CORPORATIONPrimeEnergy Corporation

NOTESTO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

March 31,June 30, 2012

(Unaudited)

(1) Interim Financial Statements:

The accompanying condensed consolidated financial statements of PrimeEnergy Corporation (“PEC” or the “Company”) have not been audited by independent public accountants. During the interim periods, the Company follows the same accounting policies as used and described in its Annual Report on Form 10-K for the year ended December 31, 2011. In accordance with applicable Securities and Exchange Commission (“SEC”) rules and regulations, the accompanying interim financial statements do not include all disclosures presented in annual financial statements and the reader should refer to the Company’s Form 10-K for the year ended December 31, 2011 filed with the SEC on March 29, 2012. In the opinion of management, the accompanying interim condensed consolidated financial statements contain all material adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of the Company’s Condensed Consolidated Balance Sheets as of March 31,June 30, 2012 and December 31, 2011, the Condensed Consolidated Statements of Operations for the three and six months ended March 31,June 30, 2012 and 2011, the Condensed Consolidated Statement of Stockholders’ Equity for the threesix months ended March 31,June 30, 2012, and the Condensed Consolidated Statements of Cash Flows for the threesix months ended March 31,June 30, 2012 and 2011. Certain amounts presented in prior period financial statements have been reclassified for consistency with current period presentation. The results for interim periods are not necessarily indicative of annual results. For purposes of disclosure in the condensed consolidated financial statements, subsequent events have been evaluated through the date the statements were issued.

Recently Issued Accounting Pronouncements

There are no new significant accounting standards applicable to the Company that have been issued but not yet adopted as of the quartersix months ended March 31,June 30, 2012.

(2) Acquisitions and Dispositions:

Historically the Company has repurchased the interests of the partners and trust unit holders in the eighteen oil and gas limited partnerships (the “Partnerships”) and the two asset and business income trusts (the “Trusts”) managed by the Company as general partner and as managing trustee, respectively. The Company purchased such interests in an amount totaling $22,000$47,000 and $124,000$169,000 for the threesix months ended March 31,June 30, 2012 and 2011, respectively.

(3) Restricted Cash and Cash Equivalents:

Restricted cash and cash equivalents include $4.69$5.09 million and $4.39 million at March 31,June 30, 2012 and December 31, 2011, respectively, of cash primarily pertaining to oil and gas revenue payments. There were corresponding accounts payable recorded at March 31,June 30, 2012 and December 31, 2011 for these liabilities. Both the restricted cash and the accounts payable are classified as current on the Condensed Consolidated Balance Sheets.

(4) Additional Balance Sheet Information:

Certain balance sheet amounts are comprised of the following:

(5) Property and Equipment:

Property and equipment at March 31,June 30, 2012 and December 31, 2011 consisted of the following:

(6) Long-Term Bank Debt:

Bank Debt:

Effective July 30, 2010 the Company entered into a Second Amended and Restated Credit Agreement between Compass Bank as agent and a syndicated group of lenders (“Credit Agreement”). The Credit Agreement has a revolving line of credit and letter of credit facility of up to $250 million with a final maturity date of July 30, 2014.2017. The credit facility is secured by substantially all of the Company’s oil and gas properties. The credit facility is subject to a borrowing base determined by the lenders taking into consideration the estimated value of PEC’s oil and gas properties in accordance with the lenders’ customary practices for oil and gas loans. This process involves reviewing PEC’s estimated proved reserves and their valuation. The borrowing base is re-determined semi-annually, and the available borrowing amount could be increased or decreased as a result of such redetermination. In addition, PEC and the lenders each have at their discretion the right to request the borrowing base be re-determined with a maximum of one such request each year. A revision to PEC’s reserves may prompt such a request on the part of the lenders, which could possibly result in a reduction in the borrowing base and availability under the credit facility. At any time if the sum of the outstanding borrowings and letter of credit exposures exceed the applicable portion of the borrowing base, PEC would be required to repay the excess amount within a prescribed period.

As of March 31,June 30, 2012, the credit facility borrowing base was $125.0 million with no required monthly reduction amount. The borrowings made within the credit facility may be placed in a base rate loan or LIBO rate loan. The Company’s borrowing rates in the credit facility provide for base rate loans at the prime rate (3.25% at March 31,June 30, 2012) plus applicable margin utilization rates that range from 1.75%1.00% to 2.0%2.00%, and LIBO rate loans at LIBO published rates plus applicable utilization rates (2.75%that range from 2.00% to 3.00% at March 31, 2012). As of March 31,June 30, 2012, the Company had in place one base rate loan and one LIBO rate loan with effective rates of 5.00% and 2.99%, respectively.

At March 31,June 30, 2012, the Company had $84.5$97.75 million of borrowings outstanding under its revolving credit facility at a weighted-average interest rate of 3.84%3.94% and $40.5$27.25 million available for future borrowings. The combined weighted average interest rates paid on outstanding bank borrowings subject to base rate and LIBO interest were 3.93%3.90% for the threesix months ended March 31,June 30, 2012 as compared to 5.67% for the threesix months ended March 31,June 30, 2011.

(7) Other Long-Term Obligations and Commitments:

Operating Leases:

The Company has several non-cancelable operating leases, primarily for rental of office space, that have a term of more than one year. The future minimum lease payments for the rest of the fiscal 2012 and thereafter for the operating leases are as follows:

Rent expense for office space for the threesix months ended March 31,June 30, 2012 and 2011 was $226,000$399,000 and $182,000,$378,000, respectively.

Asset Retirement Obligation:

A reconciliation of the liability for plugging and abandonment costs for the threesix months ended March 31,June 30, 2012 is as follows:

The Company’s liability is determined using significant assumptions, including current estimates of plugging and abandonment costs, annual inflation of these costs, the productive life of wells and a risk-adjusted interest rate. Changes in any of these assumptions can result in significant revisions to the estimated asset retirement obligation. Revisions to the asset retirement obligation are recorded with an offsetting change to producing properties, resulting in prospective changes to depreciation, depletion and amortization expense and accretion of discount. Because of the subjectivity of assumptions and the relatively long life of most of the Company’s wells, the costs to ultimately retire the wells may vary significantly from previous estimates.

In December 2011, the Company entered into a fixed price contract for the plugging and abandonment of a substantial portion of its offshore properties. In connection with this contract, the Company deposited a net $6.0 million with the contractor which is reflected in prepaid obligations at March 31, 2012 and December 31, 2011. All work under this contract is expected to bewas substantially completed inby June 30, 2012.

(8) Contingent Liabilities:

The Company, as managing general partner of the affiliated Partnerships, is responsible for all Partnership activities, including the drilling of development wells and the production and sale of oil and gas from productive wells. The Company also provides the administration, accounting and tax preparation work for the Partnerships, and is liable for all debts and liabilities of the affiliated Partnerships, to the extent that the assets of a given limited Partnership are not sufficient to satisfy its obligations. As of March 31,June 30, 2012, the affiliated Partnerships have established cash reserves in excess of their debts and liabilities and the Company believes these reserves will be sufficient to satisfy Partnership obligations.

The Company is subject to environmental laws and regulations. Management believes that future expenses, before recoveries from third parties, if any, will not have a material effect on the Company’s financial condition. This opinion is based on expenses incurred to date for remediation and compliance with laws and regulations, which have not been material to the Company’s results of operations.

From time to time, the Company is party to certain legal actions arising in the ordinary course of business. While the outcome of these events cannot be predicted with certainty, management does not expect these matters to have a materially adverse effect on the financial position or results of operations of the Company.

(9) Stock Options and Other Compensation:

In May 1989, non-statutory stock options were granted by the Company to four key executive officers for the purchase of shares of common stock. At March 31,June 30, 2012 and 2011, remaining options held by two key executive officers on 767,500 shares were outstanding and exercisable at prices ranging from $1.00 to $1.25. According to their terms, the options have no expiration date.

(10) Related Party Transactions:

The Company, as managing general partner or managing trustee, makes an annual offer to repurchase the interests of the partners and trust unit holders in certain of the Partnerships or Trusts. The Company purchased such interests in amounts totaling $22,000$47,000 and $124,000$169,000 for the threesix months ended March 31,June 30, 2012 and 2011, respectively.

Treasury stock purchases in any reported period may include shares from a related party, which may include members of the Company’s Board of Directors. In April 2012, the Company purchased 45,179 shares of common stock as treasury shares from a Director for $1.13 million.

Receivables from related parties consist of reimbursable general and administrative costs, lease operating expenses and reimbursement for property development and related costs. These receivables are due from joint venture partners, which may include members of the Company’s Board of Directors.

Payables owed to related parties primarily represent receipts collected by the Company as agent for the joint venture partners, which may include members of the Company’s Board of Directors, for oil and gas sales net of expenses.

(11) Financial InstrumentsInstruments:

Fair Value measurements:

Authoritative guidance on fair value measurements defines fair value, establishes a framework for measuring fair value and stipulates the related disclosure requirements. The Company follows a three-level hierarchy, prioritizing and defining the types of inputs used to measure fair value. The fair values of the Company’s interest rate swaps, natural gas and crude oil price collars and swaps are designated as Level 3. The following fair value hierarchy table presents information about the Company’s assets and liabilities measured at fair value on a recurring basis as of March 31,June 30, 2012 and December 31, 2011:

The following table sets forth a reconciliation of changes in the fair value of financial assets and liabilities classified as Level 3 in the fair value hierarchy for the threesix months ended March 31,June 30, 2012.

Derivative Instrument:

The Company is exposed to commodity price and interest rate risk, and management considers periodically the Company’s exposure to cash flow variability resulting from the commodity price changes and interest rate fluctuations. Futures, swaps and options are used to manage the Company’s exposure to commodity price risk inherent in the Company’s oil and gas production operations. The Company does not apply hedge accounting to any of its commodity based derivatives. Both realized and unrealized gains and losses associated with derivative instruments are recognized in earnings.

The following table sets forth the effect of derivative instruments on the condensed consolidated balance sheets as of March 31,June 30, 2012 and December 31, 2011:

The following table sets forth the effect of derivative instruments on the condensed consolidated statement of operations for the three-monthsix-month periods ended March 31,June 30, 2012 and 2011:

(12) Earnings Per Share:

Basic earnings per share are computed by dividing earnings available to common stockholders by the weighted average number of common shares outstanding during the period. Diluted earnings per share reflect per share amounts that would have resulted if dilutive potential common stock had been converted to common stock in gain periods. The following reconciles amounts reported in the financial statements:

Item 2.

MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

This report may contain statements relating to the future results of the Company that are considered “forward-looking statements” as defined in the Private Securities Litigation Reform Act of 1995 (the “PSLRA”). In addition, certain statements may be contained in the Company’s future filings with the SEC, in press releases, and in oral and written statements made by or with the approval of the Company that are not statements of historical fact and constitute forward-looking statements within the meaning of the PSLRA. Such forward-looking statements, in addition to historical information, which involve risk and uncertainties, are based on the beliefs, assumptions and expectations of management of the Company. Words such as “expects”, ‘believes”, “should”, “plans”, “anticipates”, “will”, “potential”, “could”, “intend”, “may”, “outlook”, “predict”, “project”, “would”, “estimates”, “assumes”, “likely”’ “and variations of such similar expressions are intended to identify such forward-looking statements. These statements are not guarantees of future performance and involve risks and uncertainties and are based on a number of assumptions that could ultimately prove inaccurate and, therefore, there can be no assurance that they will prove to be accurate. Actual results and outcomes may vary materially from what is expressed or forecast in such statements due to various risks and uncertainties. These risks and uncertainties include, among other things, the possibility of drilling cost overruns and technical difficulties, volatility of oil and gas prices, competition, risks inherent in the Company’s oil and gas operations, the inexact nature of interpretation of seismic and other geological and geophysical data, imprecision of reserve estimates, and the Company’s ability to replace and expand oil and gas reserves. Accordingly, stockholders and potential investors are cautioned that certain events or circumstances could cause actual results to differ materially from those projected. The forward looking statements are made as of the date of this report and other than as required by the federal securities laws, the Company assumes no obligation to update the forward-looking statement or to update the reasons why actual results could differ from those projected in the forward-looking statements.

The following discussion is intended to assist you in understanding our results of operations and our present financial condition. Our Condensed Consolidated Financial Statements and the accompanying Notes to the Condensed Consolidated Financial Statements included elsewhere in this Report contains additional information that should be referred to when reviewing this material.

OVERVIEW

We are an independent oil and natural gas company engaged in acquiring, developing and producing oil and natural gas. We presently own producing and non-producing properties located primarily in Texas, Oklahoma, West Virginia, the Gulf of Mexico, New Mexico, Colorado and Louisiana. In addition, we own a substantial amount of well servicing equipment. All of our oil and gas properties and interests are located in the United States. Assets in our principal focus areas include mature properties with long-lived reserves and significant development opportunities as well as newer properties with development and exploration potential. We believe our balanced portfolio of assets and our ongoing hedging program position us well for both the current commodity price environment and future potential upside as we develop our attractive resource opportunities. Our primary sources of liquidity are cash generated from our operations and our credit facility.

We attempt to assume the position of operator in all acquisitions of producing properties and will continue to evaluate prospects for leasehold acquisitions and for exploration and development operations in areas in which we own interests. We continue to actively pursue the acquisition of producing properties. In order to diversify and broaden our asset base, we will consider acquiring the assets or stock in other entities and companies in the oil and gas business. Our main objective in making any such acquisitions will be to acquire income producing assets so as to build stockholder value through consistent growth in our oil and gas reserve base on a cost-efficient basis.

Our cash flows depend on many factors, including the price of oil and gas, the success of our acquisition and drilling activities and the operational performance of our producing properties. We use derivative instruments to manage our commodity price risk. This practice may prevent us from receiving the full advantage of any increases in oil and gas prices above the maximum fixed amount specified in the derivative agreements and subjects us to the credit risk of the counterparties to such agreements. Since all of our derivative contracts are accounted for under mark-to-market accounting, we expect continued volatility in gains and losses on mark-to-market derivative contracts in our consolidated income statement as changes occur in the NYMEX price indices.

RECENT ACTIVITIES

During 2012, we continued our drilling program in our West Texas and Mid-Continent regions. Thru April 30,July 31, 2012, we have drilled a total of 1220 gross (9.43(16.30 net) wells, with 1119 gross (9.40(16.27 net) wells having successful completions.completions, and we have one well currently drilling. We intend to drill a total of approximately 35 gross wells (30 net) this year, primarily in the West Texas area.

In February 2012, we closed the acquisition of additional working interest in producing properties which we operate. These properties are located in our Gulf Coast region and were acquired at a net cost of $6.32 million.

During the first quartersix months of 2012, we began plugging and abandoning a substantial portionthe majority of our offshore oil and gas properties. This work is being performed under a fixed price contract and is expected to bewas substantially completed within the next three or four months.by June 30, 2012.

RESULTS OF OPERATIONS

2012 and 2011 Compared

We reported net income for the three and six months ended March 31,June 30, 2012 of $1.32$7.42 million, or $0.49$2.81 per share. Forshare and $8.75 million, or $3.28 per share, respectively as compared to $3.20 million, or $1.16 per share and $0.82 million, or $0.30 per share for the three and six months ended March 31,June 30, 2011, we reported a net loss of $2.38 million, or $0.86 per share.respectively. Net income increased inby $4.22 million and $7.93 million for the three and six months ended June 30, 2012 by $3.70 millionas compared to the same periods during 2011 primarily due to increased operating revenues including a decreasean increase in unrealized lossesgains on derivative instruments and decreased depreciation and depletion expenses partially offset by increased lease operating and depreciation and depletion expenses and income tax expenses. Operating revenuesprovisions. Unrealized gains (loss) on derivative instruments increased by $7.94$2.86 million inand $8.59 million for the three and six months ended June 30, 2012, respectively as compared to the same periods in 2011 largely due to an increasea decrease in our price per barrel realized on crude oil sales and less unrealized losses onfuture crude oil commodity contracts.prices during the 2012 periods as compared to crude oil commodity contracts held at the end of the reported periods.

The significant components of net income are discussed below.

Oil and gas sales increased $1.91decreased $1.53 million, or 9%7% from $21.12$22.36 million for the three months ended March 31,June 30, 2011 to $23.03$20.83 million for the three months ended March 31,June 30, 2012 and increased $0.39 million, or 1% from $43.48 million for the six months ended June 30, 2011 to $43.87 million for the six months ended June 30, 2012. Crude oil and natural gas sales vary due to changes in volumes of production sold and realized commodity prices. Our realized prices at the well head increaseddecreased an average of $10.11$9.68 per barrel, or 11%10% and increased $0.26 per barrel, or less than 1% on crude oil during the first quarterthree and six months ended June 30, 2012, respectively from the same periodperiods in 2011 while our average well head price for natural gas decreased $1.42$2.10 per mcf, or 24%32% and $1.78 per mcf, or 28% during the first quarterthree and six months ended June 30, 2012, respectively from the same periodperiods in 2011.

Our crude oil production increased by 21,00033,000 barrels, or 13%22% from 156,000147,000 barrels for the firstsecond quarter 2011 to 177,000180,000 barrels for the firstsecond quarter 2012 and increased by 54,000 barrels, or 18% from 303,000 barrels for the six months ended June 30, 2011 to 357,000 barrels for the six months ended June 30, 2012. Our natural gas production decreased by 11,00096,000 mcf, or 1%7% from 1,166,0001,243,000 mcf for the firstsecond quarter 2011 to 1,155,0001,147,000 mcf for the firstsecond quarter 2012 and decreased by 107,000 mcf, or 4% from 2,409,000 mcf for the six months ended June 30, 2011 to 2,302,000 mcf for the six months ended June 30, 2012. The crude oil production variances are a result of our recent drilling success in West Texas and drilling and acquisition activities in the Gulf Coast regions as we place new wells into production, partially offset by the natural decline of existing properties. The natural gas volume decreases are primarily due to the natural decline of the primary natural gas producing offshore properties, partially offset by production from wells in the West Texas region recently placed into production.

The following table summarizes the primary components of production volumes and average sales prices realized for the three and six months ended March 31,June 30, 2012 and 2011 (excluding realized gains and losses from derivatives).