This Annual Report on Form 10-K and the documents incorporated herein by reference contain forward-looking statements based on expectations, estimates, and projections as of the date of this filing. These statements by their nature are subject to risks, uncertainties, and assumptions and are influenced by various factors. As a consequence, actual results may differ materially from those expressed in the forward-looking statements. See the risk factors set forth in Item 1A of this Form 10-K and Part II, Item 7A—Quantitative and Qualitative Disclosures About Market Risk—Forward-Looking Statements and Risk of this Form 10-K.

General

Apache Corporation, a Delaware corporation formed in 1954, is an independent energy company that explores for, develops, and produces natural gas, crude oil, and natural gas liquids. We currently have exploration and production interests in five countries: the U.S., Canada, Egypt, Australia, and the U.K. North Sea (North Sea). Apache also pursues exploration interests in other countries that may over time result in reportable discoveries and development opportunities. We treat all operations as one line of business.

Our common stock, par value $0.625 per share, has been listed on the New York Stock Exchange (NYSE) since 1969, on the Chicago Stock Exchange (CHX) since 1960, and on the NASDAQ National Market (NASDAQ) since 2004. On June 10 and 11, 2014, we filed certifications of our compliance with the listing standards of the NYSE and the NASDAQ, including our principal executive officer’s certification of compliance with the NYSE standards. Through our website, www.apachecorp.com , you can access, free of charge, electronic copies of the charters of the committees of our Board of Directors, other documents related to our corporate governance (including our Code of Business Conduct and Governance Principles), and documents we file with the SEC, including our annual reports on Form 10-K, quarterly reports on Form 10-Q and current reports on Form 8-K, as well as any amendments to these reports filed or furnished pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934. Included in our annual and quarterly reports are the certifications of our principal executive officer and our principal financial officer that are required by applicable laws and regulations. Access to these electronic filings is available as soon as reasonably practicable after we file such material with, or furnish it to, the SEC. You may also request printed copies of our committee charters or other governance documents free of charge by writing to our corporate secretary at the address on the cover of this report. Our reports filed with the SEC are made available to read and copy at the SEC’s Public Reference Room at 100 F Street, N.E., Washington, D.C., 20549. You may obtain information about the Public Reference Room by contacting the SEC at 1-800-SEC-0330. Reports filed with the SEC are also made available on its website at www.sec.gov . From time to time, we also post announcements, updates, and investor information on our website in addition to copies of all recent press releases. Information on our website or any other website is not incorporated by reference into, and does not constitute a part of, this Annual Report on Form 10-K.

Properties to which we refer in this document may be held by subsidiaries of Apache Corporation. References to “Apache” or the “Company” include Apache Corporation and its consolidated subsidiaries unless otherwise specifically stated.

Business Strategy

Apache’s mission is to grow a profitable exploration and production company in a safe and environmentally responsible manner for the long-term benefit of our shareholders. Apache’s long-term perspective has many dimensions, which are centered on the following core strategic components:

1

Table of Contents

Throughout the cycles of our industry, this strategy has underpinned our ability to deliver long-term production and reserve growth and achieve competitive returns on invested capital for the benefit of our shareholders. We have increased reserves 23 out of the last 29 years and production 32 out of the past 36 years, a testament to our consistency over the long-term.

We continuously review and optimize our portfolio of assets in response to changing industry and economic conditions. Over the last several years, Apache has taken action to monetize certain nonstrategic international assets, and enhance and streamline our North American onshore portfolio through a series of divestitures of noncore assets. These include:

We intend to focus our growth initiatives on our North American onshore portfolio. Our Egypt and the North Sea regions provide a strong complement to our North American production and cash flow by generating

2

Table of Contents

steady and attractive rates of return and excess cash flow. This is particularly true in the context of the recent oil price downturn, as the cash flows from both Egypt and the North Sea are less sensitive to falling oil prices than our North American assets. We currently have no intention to exit Egypt or the North Sea. Our non-LNG Australian assets offer a dynamic exploration opportunity; however, we continue to evaluate this area for potential monetization.

While we cannot predict the length or depth of the current oil price correction, or the timing and extent of a potential price rebound, we have moved quickly and decisively regarding what we can control: the timing and levels of capital spending and our cost structure. Specifically, during the third quarter of 2014 we were operating 91 rigs onshore in North America, and by the end of February 2015, our rig count was reduced to 27 rigs. We also reduced the number of completion crews and will delay completing some of our wells in backlog until the associated service costs align with the current commodity price environment. In addition to well cost initiatives, we have taken steps to reduce both lease operating and general and administrative expenses and will continue to take proactive measures to reduce them further. We intend to manage the current downturn as we have other downturns throughout our 60-year history. Apache has proven its ability to capitalize on historical cycles of low commodity prices by focusing on a strong balance sheet, cost discipline, operating efficiency, adding to its extensive inventory of drilling locations, and ensuring we are prepared to take advantage of potential opportunities that arise as a result of low commodity prices, such as the availability of key acreage at attractive prices.

For a more in-depth discussion of our growth strategy, 2014 results, and the Company’s capital resources and liquidity, please see Part II, Item 7—Management’s Discussion and Analysis of Financial Condition and Results of Operations of this Form 10-K.

Geographic Area Overviews

During 2014, we had exploration and production interests in six countries: the U.S., Canada, Egypt, Australia, the U.K. North Sea, and Argentina. Apache also pursues exploration interests in other countries that may over time result in reportable discoveries and development opportunities. In March 2014, the Company completed the sale of all of its operations in Argentina. Results of operations and cash flows for Argentina operations are reflected as discontinued operations in the Company’s financial statements and are not included in the following table.

The following table sets out a brief comparative summary of certain key 2014 data for each of our operating areas. Additional data and discussion is provided in Part II, Item 7 of this Form 10-K.

3

Table of Contents

North America

Apache’s North American onshore and offshore asset base primarily comprises operations in the Permian Basin, the Anadarko basin in western Oklahoma and the Texas Panhandle, Gulf Coast areas of the U.S., and in Western Canada. We also have leasehold acreage holdings in the Cook Inlet of Alaska and other areas where we are pursuing exploration opportunities. Over the past several years, the Company acquired significant acreage positions in many attractive basins and plays across North America. This portfolio expansion phase shifted during 2013 and 2014 when we completed strategic divestitures to rebalance our portfolio to an asset mix that we believe will drive more predictable growth and deliver increased value to our shareholders. As part of this effort, Apache’s drilling activity has focused on our North America onshore assets, which delivered liquids growth of 19 percent during 2014 excluding the impacts of divestitures. Our North American asset base has a significant inventory of drilling opportunities and base production that provides a foundation for the Company to be flexible in its approach to capital allocation. This flexibility is critical to managing cash flows given volatile commodity prices for crude oil and natural gas.

With the recent decline in oil prices and reduction in our expected cash flow, we have initially set our 2015 capital budget for North America at $2.1 billion to $2.3 billion. This reflects an approximately 65 percent decline from the prior year. This budget covers planned expenditures for drilling, completions, recompletion projects, equipment upgrades, expansion of existing facilities and equipment, plugging and abandonment, seismic studies, and leasing additional acreage.

North America Onshore

Overview  We have access to significant liquid hydrocarbons across our 12 million gross acres onshore in the U.S. and Canada, approximately 60 percent of which is undeveloped. Approximately 55 percent of Apache’s worldwide equivalent 2014 production and 68 percent of our estimated year-end proved reserves were in our U.S. and Canada onshore regions. To manage our development efforts across broad acreage positions within North America, our onshore assets are divided into four regions: Permian, Gulf Coast, Central, and Canada.

Permian Region  Our Permian region controls over 3.2 million gross acres with exposure to numerous plays across the Permian Basin. Apache is one of the largest operators in the Permian Basin, with more than 14,500 producing wells in 155 fields, including 47 waterfloods and seven CO ₂ floods. Total region production for 2014 was up 25 percent sequentially as a result of an active drilling program where we ran an average of 40 rigs during the year. Production in the region has increased for 16 consecutive quarters. During the year, we drilled or participated in drilling 728 wells, of which 244 were horizontal. The Permian region’s year-end 2014 estimated proved reserves were 970 MMboe, representing 7 percent growth over year-end 2013.

Over the past several years, the region has been testing numerous formations and building a large inventory of horizontal opportunities in several plays across our acreage position. In 2014, production growth was driven by Wolfcamp wells in the Barnhart area and in the Southern Midland Basin, the Bone Springs development program in the Delaware basin, and Yeso drilling on the Northwest shelf.

We continue to balance large development programs with exploration activity in several new areas. Given its acreage holdings, recent seismic data acquisitions and continued exploration efforts, the region has built a deep portfolio of drilling inventory and opportunities to sustain our activity for many years.

Gulf Coast Region  Apache’s Gulf Coast region is known for its proven onshore and near-shore basins of Texas and Louisiana where it has a significant acreage position of approximately 1.2 million gross acres, including approximately 285,000 mineral fee acres. Total region production in 2014 was 30 Mboe/d, of which 50 percent was oil and natural gas liquids.

During the year, the region continued to delineate its East Texas Eagle Ford play, primarily in Brazos and Burleson counties, with consistently strong results. As our drilling program has continued to advance, we

4

Table of Contents

acquired over $600 million of additional Eagle Ford acreage in surrounding areas in 2014. The region drilled or participated in drilling 77 wells in 2014.

In December 2014, Apache sold its working interest in approximately 90,000 net acres in southern Louisiana and Mississippi for $560 million. The effective date of the transaction is October 1, 2014. Apache’s Gulf Coast regional production for 2015 will be almost entirely attributable to the East Texas Eagle Ford play.

Central Region  The Central region controls 2.2 million gross acres and includes 3,150 producing wells primarily in western Oklahoma and the Texas Panhandle. The majority of our drilling activity during 2014 was focused in legacy Anadarko basin formations such as the Granite Wash, Marmaton, Cottage Grove, and Cleveland. Total region production in 2014 was 91 Mboe/d, of which 52 percent was oil and natural gas liquids. As of year-end, the Central region’s estimated proved reserves totaled 217 MMboe.

Throughout the year, Apache continued to build on its drilling inventory and development opportunities in the Whittenburg basin, located just west of our Anadarko basin properties. Apache’s Canyon Wash sand and the prolific Canyon Lime play will be the focus of our region’s drilling activity in 2015.

In December 2014, Apache completed the sale of non-core assets in the Anadarko basin, including approximately 115,000 net acres in Wheeler County, Texas, and western Oklahoma, for approximately $730 million. The effective date of the transaction is October 1, 2014.

Canada Region Apache entered the Canadian market in 1995 and currently holds nearly 4.4 million gross acres across the provinces of British Columbia, Alberta, and Saskatchewan. Most of Canada’s acreage is held-by-production. The region’s large acreage position provides portfolio diversification as well as significant drilling opportunities. Our Canadian region provided approximately 12 percent of Apache’s 2014 worldwide production and held 414 MMboe of estimated proved reserves at year-end.

In 2014, Apache drilled or participated in drilling 106 wells in the region with successful results in the established Swan Hills, Viking, Bluesky, and Glauconite developments. In addition, Canada further established key plays in the Duvernay and Montney formations with a focus on reducing drilling and completion costs. In the Duvernay, we began drilling our first seven-well pad and expect to see test rates in the third quarter of 2015. Our Montney drilling has been focused in the Wapiti area.

In our continuing assessment of the Company’s North American portfolio, we divested approximately 328,400 net acres in the Ojay, Noel, and Wapiti areas in April 2014. Apache retained 100 percent of its working interest in horizons below the Cretaceous in the Wapiti area, including rights to the liquids-rich Montney and other deeper horizons. We also signed an agreement to divest our working interest in the Kitimat LNG development and approximately 333,000 of our net acres in the Horn River and Liard natural gas basins of British Columbia. The transaction is expected to close in the first quarter of 2015.

North America Offshore

Gulf of Mexico Region The Gulf of Mexico region comprises assets in approximately 617 blocks in the offshore waters of the Gulf of Mexico. In 2014, Apache combined its deepwater and shelf technical teams to focus on subsalt and other deeper exploration opportunities in water depths less than 1,000 feet, which have been relatively untested by the industry. In addition to the exploration and development of properties in shallower water, Apache continues to pursue joint venture and other monetization opportunities for its deepwater prospects, which offer exposure to significant reserve and production potential in underexplored and oil-prone areas in water depths greater than 1,000 feet. During 2014, Apache’s Gulf of Mexico region contributed 10.5 Mboe/d to the Company’s total production.

5

Table of Contents

On June 30, 2014, Apache completed the sale of non-operated interests in the Lucius and Heidelberg development projects and 11 primary term deepwater exploration blocks to a subsidiary of Freeport-McMoRan Copper & Gold Inc. and other interest owners for $1.4 billion.

North America Marketing

In general, most of our North American gas is sold at either monthly or daily market prices. Also, from time to time, the Company will enter into fixed physical sales contracts for durations of up to one-year. These physical sales volumes are typically sold at fixed prices over the term of the contract. Our natural gas is sold primarily to local distribution companies (LDCs), utilities, end-users, marketers, and integrated major oil companies. We strive to maintain a diverse client portfolio, which is intended to reduce the concentration of credit risk. We transport some of our Canadian natural gas under firm transportation contracts to delivery points into the U.S. in order to diversify our market exposure.

Apache primarily markets its North American crude oil to integrated major oil companies, marketing and transportation companies, and refiners based on a West Texas Intermediate (WTI) price, adjusted for quality, transportation and a market-reflective differential.

In the U.S., our objective is to maximize the value of crude oil sold by identifying the best markets and most economical transportation routes available to move the product. Sales contracts are generally 30-day evergreen contracts that renew automatically until canceled by either party. These contracts provide for sales that are priced daily at prevailing market prices. Also, from time to time, the Company will enter into physical term sales contracts for durations up to five years. These term contracts typically have a firm transport commitment and often provide for the higher of prevailing market prices from multiple market hubs.

In Canada, the crude is transported by pipeline or truck within Western Canada to market hubs in Alberta and Manitoba where it is sold, allowing for a more diversified group of purchasers and a higher netback price. A portion of our trucked barrels are delivered and sold at rail terminals. We evaluate our transport options monthly to maximize our netback prices.

Apache’s NGL production is sold under contracts with prices based on local supply and demand conditions, less the costs for transportation and fractionation, or on a weighted-average sales price received by the purchaser.

International

Apache’s international assets are located in Egypt, Australia, and offshore the U.K. in the North Sea. In 2014, international assets contributed 43 percent of our production and 50 percent of our oil and gas revenues. Approximately 31 percent of our estimated proved reserves at year-end were located outside North America.

Egypt

Overview Our activity in Egypt began in 1994 with our first Qarun discovery well, and today we are one of the largest acreage holders in Egypt’s Western Desert. At year-end 2014, we held 6.7 million gross acres, of which approximately 71 percent is undeveloped, providing us with considerable exploration and development opportunities for the future. The region had gross oil production of 197 Mb/d and gross natural gas production of 895 MMcf/d in 2014, or 88 Mb/d and 370 MMcf/d net to Apache’s consolidated holdings.

Sinopec holds a one-third minority interest in Apache’s Egypt oil and gas business. At December 31, 2014, our Egypt region had estimated proved reserves of 280 MMboe, of which 93 MMboe is attributable to Sinopec’s noncontrolling interest. Our estimated proved reserves in Egypt are reported under the economic interest method and exclude the host country’s share of reserves.

6

Table of Contents

Our operations in Egypt are conducted pursuant to production-sharing agreements in 24 separate concessions, under which the contractor partners pay all operating and capital expenditure costs for exploration and development. Development leases within concessions currently have expiration dates ranging from 2 to 25 years, with extensions possible for additional commercial discoveries or on a negotiated basis. A percentage of the production on development leases, usually up to 40 percent, is available to the contractor partners to recover operating and capital expenditure costs, with the balance generally allocated between the contractor partners and the Egyptian General Petroleum Corporation (EGPC) on a contractually defined basis.

Our growth in Egypt has been driven by an ongoing drilling program, and we have historically been one of the most active drillers in the Western Desert. We drilled 171 development and 49 exploration wells in 2014. Approximately 45 percent of our exploration wells were successful, further expanding our presence in the westernmost concessions and unlocking additional opportunities in existing plays. A key component of the region’s success has been the ability to acquire and evaluate 3-D seismic surveys that enable our technical teams to consistently high-grade existing prospects and identify new targets across multiple pay horizons in the Cretaceous, Jurassic, and deeper Paleozoic formations.

Following four years of political turmoil, in January 2014, Egyptians voted on and overwhelmingly approved a new constitution, and in June 2014, Mr. Abdel Fattah el-Sisi was sworn in as president of Egypt.

Apache’s operations, located in remote locations in the Western Desert, have not experienced production interruptions, and we have continued to receive development lease approvals for our drilling program. However, a further deterioration in the political, economic, and social conditions or other relevant policies of the Egyptian government, such as changes in laws or regulations, export restrictions, expropriation of our assets or resource nationalization, and/or forced renegotiation or modification of our existing contracts with EGPC, or threats or acts of terrorism by groups such as ISIS, could materially and adversely affect our business, financial condition, and results of operations.

Marketing Our gas production is sold to EGPC primarily under an industry-pricing formula, a sliding scale based on Dated Brent crude oil with a minimum of $1.50 per MMBtu and a maximum of $2.65 per MMBtu, plus an upward adjustment for liquids content. The region averaged $2.96 per Mcf in 2014.

Oil from the Khalda Concession, the Qarun Concession, and other nearby Western Desert blocks is sold to third parties in the export market or to EGPC when called upon to supply domestic demand. Oil sales are exported from or sold at one of two terminals on the northern coast of Egypt. Oil production that is sold to EGPC is sold on a spot basis priced at Brent with a monthly EGPC official differential applied.

Australia

Overview  Apache’s holdings in Australia are focused offshore Western Australia in the Carnarvon, Exmouth, and Browse basins, with production operations in the Carnarvon and Exmouth basins. We have operated in the Carnarvon basin since acquiring the gas processing facilities on Varanus Island and adjacent producing properties in 1993. At the end of 2014 we controlled approximately 21 million gross acres offshore Western Australia through 34 exploration permits, 18 production licenses, and 10 retention leases. Over the past decade, the region’s exploration activity has established a significant pipeline of projects that are expected to contribute to production growth as they are brought online in the coming years. As of year-end 2014, approximately 96 percent of our acreage is undeveloped. During 2014, the region had net production of 21 Mb/d and 214 MMcf/d, contributing 9 percent of worldwide consolidated production and 13 percent of year-end consolidated proved reserves.

The region participated in drilling 12 offshore wells in 2014, of which 6 were exploration wells. Four of the exploration wells were successful. This compares to 12 wells drilled in the prior year. Development work during the year also continued for the Coniston oil field project, which lies just north of the Van Gogh field. The field

7

Table of Contents

will be produced via subsea completions tied back to the Ningaloo Vision Floating Production Storage and Offloading Vessel (FPSO) at Van Gogh. Modifications and upgrades to the FPSO are underway, and the final phase of work is planned for the first half of 2015, with first oil production expected shortly thereafter. Apache has a 52.5 percent working interest in the field.

As noted previously, on December 15, 2014, Apache announced an agreement with Woodside Petroleum to sell its 13 percent interest in the Chevron-operated Wheatstone LNG project. The sale also includes Apache’s 65 percent interest in the WA-49-L block, which includes the Julimar and Brunello offshore gas fields and the Balnaves oil development. The transaction will have an effective date of June 30, 2014, and under terms of the agreement, Woodside will reimburse Apache for its net expenditure for Wheatstone subsequent to that date. Following the transaction’s expected close in the first quarter of 2015, Apache will continue to hold upstream acreage offshore Western Australia in the Carnarvon, Exmouth, and Canning basins along with related hydrocarbon reserves and production.

Marketing Western Australia has historically had a local market for natural gas with a limited number of buyers and sellers resulting in sales under mostly long-term, fixed-price contracts, many of which contain periodic price revision clauses based on either the Australian consumer price index or a commodity linkage. As of December 31, 2014, Apache had 20 active gas contracts in Australia with expiration dates ranging from June 2015 to December 2026. Recent increases in demand and higher development costs have increased the prices required from the local market in order to support the development of new supplies. As a result, market prices negotiated on recent contracts have continued to be higher than historical levels.

We directly market all of our Australian crude oil production into Australian domestic and international markets at prices generally indexed to Dated Brent benchmark crude oil prices plus premiums, which typically result in price realizations above crude sold at WTI-based prices.

North Sea

Overview Apache entered the North Sea in 2003 after acquiring an approximate 97 percent working interest in the Forties field (Forties). Since acquiring Forties, Apache has actively invested in the region and has established a large inventory of drilling prospects through successful exploration programs and the interpretation of acquired 3-D and 4-D seismic data. Building upon its success in Forties, in 2011 Apache acquired Mobil North Sea Limited, providing the region with additional exploration and development opportunities across numerous fields, including operated interests in the Beryl, Nevis, Nevis South, Skene, and Buckland fields and non-operated interests in the Maclure field. In total, Apache has interest in approximately 1 million gross acres in the U.K. North Sea.

In 2014, the North Sea region contributed 11 percent of worldwide consolidated production and 6 percent of year-end estimated proved reserves. In 2014, 22 development wells were drilled in the North Sea, of which 20 were productive. In the Forties area in the Tonto, Maule, and Bacchus fields, Apache has benefited from extensive 4-D seismic interpretations over the last few years and has targeted areas of bypassed oil in the mature reservoir. The Forties Alpha Satellite Platform (FASP) was also commissioned during the third quarter of 2014, providing an additional 18 drilling slots as well as power generation, fluid separation, and gas lift compression.

Marketing We have traditionally sold our North Sea crude oil under both term contracts and spot cargoes. The term sales are composed of a market-based index price plus a premium, which reflects the higher market value for term arrangements. The prices received for spot cargoes are market driven and can trade at a premium or discount to the market-based index.

Natural gas from the Beryl field is processed through the SAGE gas plant operated by Apache. The gas is sold to a third party at the St. Fergus entry point of the national grid on a National Balancing Point index price basis. The condensate mix from the SAGE plant is processed further downstream. The split streams of propane

8

Table of Contents

and butane are sold on a monthly entitlement basis, and condensate is sold on a spot basis at the Braefoot Bay terminal using index pricing less transportation.

Argentina

On March 12, 2014, Apache’s subsidiaries completed the sale of all of the Company’s operations in Argentina to YPF Sociedad Anónima for $800 million (subject to customary closing adjustments) plus the assumption of $52 million of bank debt as of June 30, 2013. The results of operations related to Argentina have been classified as discontinued operations in all periods presented in this Annual Report on Form 10-K.

Other Exploration

New Ventures

Apache’s global New Ventures team provides exposure to new growth opportunities by looking outside of the Company’s traditional core areas and targeting higher-risk, higher-reward exploration opportunities located in frontier basins as well as new plays in more mature basins. Plans for 2015 include drilling a deepwater well offshore Suriname.

Major Customers

In 2014, 2013, and 2012 purchases by Royal Dutch Shell plc and its subsidiaries accounted for 19 percent, 24 percent, and 20 percent, respectively, of the Company’s worldwide oil and gas production revenues.

Drilling Statistics

Worldwide in 2014 we participated in drilling 1,478 gross wells, with 1,407 (95 percent) completed as producers. Historically, our drilling activities in the U.S. have generally concentrated on exploitation and extension of existing producing fields rather than exploration. As a general matter, our operations outside of the U.S. focus on a mix of exploration and development wells. In addition to our completed wells, at year-end a number of wells had not yet reached completion: 318 gross (214.7 net) in the U.S.; 27 gross (19.0 net) in Canada; 35 gross (32.5 net) in Egypt; and 3 gross (2.2 net) in the North Sea.

9

Table of Contents

The following table shows the results of the oil and gas wells drilled and completed for each of the last three fiscal years:

Gross natural gas and crude oil wells include 640 wells with multiple completions.

10

Table of Contents

As of December 31, 2014, Apache had 3.1 million net undeveloped acres scheduled to expire by year-end 2015 if production is not established or we take no other action to extend the terms. Additionally, Apache has

11

Table of Contents

1.7 million and 1.9 million net undeveloped acres set to expire in 2016 and 2017, respectively. We strive to extend the terms of many of these licenses and concession areas through operational or administrative actions, but cannot assure that such extensions can be achieved on an economic basis or otherwise on terms agreeable to both the Company and third parties including governments.

Exploration concessions in our Egypt region comprise a significant portion of our net undeveloped acreage expiring over the next three years. We have 1.0 million net undeveloped acres set to expire in 2015 and 2016. Apache will continue to pursue acreage extensions in areas in which it believes exploration opportunities exist and over the past year has been successful in being awarded six-month extensions on targeted concessions. Longer term extensions are also being finalized with EGPC. In Australia, 1.4 million, 0.4 million and 1.1 million net undeveloped acres are scheduled to expire in 2015, 2016 and 2017, respectively. There were no reserves recorded on this undeveloped acreage.

Separately, with the announced divestiture of our Kitimat and Wheatstone LNG projects, an additional 79,000 net undeveloped acres and 100,000 net developed acres in Australia and 330,000 net undeveloped acres in Canada will be sold as a part of the transaction.

As of December 31, 2014, 23 percent of U.S. net undeveloped acreage and 63 percent of Canadian undeveloped acreage was held by production.

Estimated Proved Reserves and Future Net Cash Flows

Proved oil and gas reserves are the estimated quantities of natural gas, crude oil, condensate, and NGLs that geological and engineering data demonstrate with reasonable certainty to be recoverable in future years from known reservoirs under existing conditions, operating conditions, and government regulations. Estimated proved developed oil and gas reserves can be expected to be recovered through existing wells with existing equipment and operating methods. The Company reports all estimated proved reserves held under production-sharing arrangements utilizing the “economic interest” method, which excludes the host country’s share of reserves.

Estimated reserves that can be produced economically through application of improved recovery techniques are included in the “proved” classification when successful testing by a pilot project or the operation of an active, improved recovery program using reliable technology establishes the reasonable certainty for the engineering analysis on which the project or program is based. Economically producible means a resource that generates revenue that exceeds, or is reasonably expected to exceed, the costs of the operation. Reasonable certainty means a high degree of confidence that the quantities will be recovered. Reliable technology is a grouping of one or more technologies (including computational methods) that has been field-tested and has been demonstrated to provide reasonably certain results with consistency and repeatability in the formation being evaluated or in an analogous formation. In estimating its proved reserves, Apache uses several different traditional methods that can be classified in three general categories: (1) performance-based methods; (2) volumetric-based methods; and (3) analogy with similar properties. Apache will, at times, utilize additional technical analysis, such as computer reservoir models, petrophysical techniques, and proprietary 3-D seismic interpretation methods, to provide additional support for more complex reservoirs. Information from this additional analysis is combined with traditional methods outlined above to enhance the certainty of our reserve estimates.

Proved undeveloped reserves include those reserves that are expected to be recovered from new wells on undrilled acreage, or from existing wells where a relatively major expenditure is required for recompletion. Undeveloped reserves may be classified as proved reserves on undrilled acreage directly offsetting development areas that are reasonably certain of production when drilled, or where reliable technology provides reasonable certainty of economic producibility. Undrilled locations may be classified as having undeveloped reserves only if a development plan has been adopted indicating that they are scheduled to be drilled within five years, unless specific circumstances justify a longer time period.

12

Table of Contents

The following table shows proved oil, NGL, and gas reserves as of December 31, 2014, based on average commodity prices in effect on the first day of each month in 2014, held flat for the life of the production, except where future oil and gas sales are covered by physical contract terms. This table shows reserves on a boe basis in which natural gas is converted to an equivalent barrel of oil based on a 6:1 energy equivalent ratio. This ratio is not reflective of the current price ratio between the two products.

As of December 31, 2014, Apache had total estimated proved reserves of 1,074 MMbbls of crude oil, 282 MMbbls of NGLs, and 6.2 Tcf of natural gas. Combined, these total estimated proved reserves are the energy equivalent of 2.4 billion barrels of oil or 14.4 Tcf of natural gas, of which oil represents 44.8 percent. As of December 31, 2014, the Company’s proved developed reserves totaled 1,651 MMboe and estimated PUD reserves totaled 745 MMboe, or approximately 31 percent of worldwide total proved reserves. Apache has elected not to disclose probable or possible reserves in this filing.

The Company’s estimates of proved reserves, proved developed reserves and PUD reserves as of December 31, 2014, 2013, and 2012, changes in estimated proved reserves during the last three years, and estimates of future net cash flows from proved reserves are contained in Note 14—Supplemental Oil and Gas Disclosures in the Notes to Consolidated Financial Statements set forth in Part IV, Item 15 of this Form 10-K. Estimated future net cash flows were calculated using a discount rate of 10 percent per annum, end of period costs, and an unweighted arithmetic average of commodity prices in effect on the first day of each of the previous 12 months, held flat for the life of the production, except where prices are defined by contractual arrangements.

Proved Undeveloped Reserves

The Company’s total estimated PUD reserves of 745 MMboe as of December 31, 2014, decreased by 68 MMboe from 813 MMboe of PUD reserves estimated at the end of 2013. During the year, Apache converted 134 MMboe of PUD reserves to proved developed reserves through development drilling activity. In North America, we converted 108 MMboe, with the remaining 26 MMboe in our international areas. We sold 150 MMboe and acquired 18 MMboe of PUD reserves during the year. We added 197 MMboe of new PUD reserves through extensions and discoveries.

During the year, a total of approximately $3.6 billion was spent on projects associated with reserves that were carried as PUD reserves at the end of 2013. A portion of our costs incurred each year relate to development

13

Table of Contents

projects that will be converted to proved developed reserves in future years. We spent $1.9 billion on PUD reserve development activity in North America and $1.7 billion in the international areas. Other than our Julimar/Brunello development project, which is tied to the construction schedule of the Wheatstone LNG project, with projected first production in 2016, we had no material amounts of PUD reserves that have remained undeveloped for five years or more after they were initially disclosed as PUD reserves and no material amounts of PUD reserves which are scheduled to be developed beyond five years from December 31, 2014.

Preparation of Oil and Gas Reserve Information

Apache’s reported reserves are reasonably certain estimates which, by their very nature, are subject to revision. These estimates are reviewed throughout the year and revised either upward or downward, as warranted.

Apache’s proved reserves are estimated at the property level and compiled for reporting purposes by a centralized group of experienced reservoir engineers that is independent of the operating groups. These engineers interact with engineering and geoscience personnel in each of Apache’s operating areas and with accounting and marketing employees to obtain the necessary data for projecting future production, costs, net revenues, and ultimate recoverable reserves. All relevant data is compiled in a computer database application, to which only authorized personnel are given security access rights consistent with their assigned job function. Reserves are reviewed internally with senior management and presented to Apache’s Board of Directors in summary form on a quarterly basis. Annually, each property is reviewed in detail by our corporate and operating region engineers to ensure forecasts of operating expenses, netback prices, production trends, and development timing are reasonable.

Apache’s Executive Vice President of Corporate Reservoir Engineering is the person primarily responsible for overseeing the preparation of our internal reserve estimates and for coordinating any reserves audits conducted by a third-party engineering firm. He has a Bachelor of Science degree in Petroleum Engineering and over 30 years of industry experience with positions of increasing responsibility within Apache’s corporate reservoir engineering department. The Executive Vice President of Corporate Reservoir Engineering reports directly to our Chief Executive Officer.

The estimate of reserves disclosed in this Annual Report on Form 10-K is prepared by the Company’s internal staff, and the Company is responsible for the adequacy and accuracy of those estimates. However, the Company engages Ryder Scott Company, L.P. Petroleum Consultants (Ryder Scott) to review our processes and the reasonableness of our estimates of proved hydrocarbon liquid and gas reserves. Apache selects the properties for review by Ryder Scott based primarily on relative reserve value. We also consider other factors such as geographic location, new wells drilled during the year and reserves volume. During 2014, the properties selected for each country ranged from 83 to 100 percent of the total future net cash flows discounted at 10 percent. These properties also accounted for over 96 percent of the reserves value of our international proved reserves and of the new wells drilled in each country. In addition, all fields containing five percent or more of the Company’s total proved reserves volume were included in Ryder Scott’s review. The review covered 85 percent of total proved reserves, including 91 percent of proved developed reserves and 72 percent of PUD reserves.

During 2014, 2013, and 2012, Ryder Scott’s review covered 91, 92, and 88 percent, respectively, of the Company’s worldwide estimated proved reserves value and 85, 86, and 83 percent, respectively, of the Company’s total proved reserves volume. Ryder Scott’s review of 2014 covered 83 percent of U.S, 75 percent of Canada, 99.5 percent of Australia, 86 percent of Egypt, and 94 percent of the U.K.’s total proved reserves.

Ryder Scott’s review of 2013 covered 84 percent of U.S., 82 percent of Canada, 63 percent of Argentina, 99 percent of Australia, 88 percent of Egypt, and 88 percent of the U.K.’s total proved reserves.

Ryder Scott’s review of 2012 covered 81 percent of U.S., 78 percent of Canada, 64 percent of Argentina, 99 percent of Australia, 84 percent of Egypt, and 88 percent of the U.K.’s total proved reserves.

14

Table of Contents

We have filed Ryder Scott’s independent report as an exhibit to this Form 10-K.

According to Ryder Scott’s opinion, based on their review, including the data, technical processes, and interpretations presented by Apache, the overall procedures and methodologies utilized by Apache in determining the proved reserves comply with the current SEC regulations, and the overall proved reserves for the reviewed properties as estimated by Apache are, in aggregate, reasonable within the established audit tolerance guidelines as set forth in the Society of Petroleum Engineers auditing standards.

Employees

On December 31, 2014, we had 4,950 employees.

Offices

Our principal executive offices are located at One Post Oak Central, 2000 Post Oak Boulevard, Suite 100, Houston, Texas 77056-4400. At year-end 2014, we maintained regional exploration and/or production offices in Midland, Texas; San Antonio, Texas; Tulsa, Oklahoma; Houston, Texas; Calgary, Alberta; Cairo, Egypt; Perth, Western Australia; and Aberdeen, Scotland. Apache leases all of its primary office space. The current lease on our principal executive offices runs through December 31, 2018. For information regarding the Company’s obligations under its office leases, please see Part II, Item 7—Management’s Discussion and Analysis of Financial Condition and Results of Operations—Capital Resources and Liquidity—Contractual Obligations and Note 8—Commitments and Contingencies in the Notes to Consolidated Financial Statements set forth in Part IV, Item 15 of this Form 10-K.

Title to Interests

As is customary in our industry, a preliminary review of title records, which may include opinions or reports of appropriate professionals or counsel, is made at the time we acquire properties. We believe that our title to all of the various interests set forth above is satisfactory and consistent with the standards generally accepted in the oil and gas industry, subject only to immaterial exceptions that do not detract substantially from the value of the interests or materially interfere with their use in our operations. The interests owned by us may be subject to one or more royalty, overriding royalty, or other outstanding interests (including disputes related to such interests) customary in the industry. The interests may additionally be subject to obligations or duties under applicable laws, ordinances, rules, regulations, and orders of arbitral or governmental authorities. In addition, the interests may be subject to burdens such as production payments, net profits interests, liens incident to operating agreements and current taxes, development obligations under oil and gas leases, and other encumbrances, easements, and restrictions, none of which detract substantially from the value of the interests or materially interfere with their use in our operations.

Additional Information about Apache

In this section, references to “we,” “us,” “our,” and “Apache” include Apache Corporation and its consolidated subsidiaries, unless otherwise specifically stated.

Remediation Plans and Procedures

Apache and its wholly owned subsidiary, Apache Deepwater LLC (ADW), developed Oil Spill Response Plans (the Plans) for their respective Gulf of Mexico operations to ensure rapid and effective responses to spill events that may occur on such entities’ operated properties as required by the Bureau of Safety and Environmental Enforcement (BSEE). Annually, drills are conducted to measure and maintain the effectiveness of the Plans. These drills include the participation of spill response contractors, representatives of Clean Gulf Associates (CGA), and representatives of governmental agencies.

15

Table of Contents

In the event of a spill, CGA is the primary oil spill response association available to Apache and ADW. Both Apache and ADW are members of CGA, a not-for-profit association of producing and pipeline companies operating in the Gulf of Mexico. CGA was created to provide a means of effectively staging response equipment and providing immediate spill response for its member companies’ operations in the Gulf of Mexico. In the event of a spill, CGA’s equipment, which is positioned at various staging points around the Gulf, is ready to be mobilized.

In the event that CGA resources are already being utilized, other resources are available to Apache. Apache is a member of Oil Spill Response Limited (OSRL), which entitles any Apache entity worldwide to access OSRL’s service. In addition, ADW is a member of Marine Spill Response Corporation (MSRC) and National Response Corporation (NRC), and their resources are available to ADW for its deepwater Gulf of Mexico operations. The equipment and resources available to MSRC and NRC changes from time to time, and current information is generally available on each company’s website.

An Apache subsidiary is also a member of the Marine Well Containment Company (MWCC) to help the Company fulfill the government’s permit requirements for containment and oil spill response plans in deepwater Gulf of Mexico operations. MWCC is a not-for-profit, stand-alone organization whose goal is to improve capabilities for containing an underwater well control incident in the U.S. Gulf of Mexico. Members and their affiliates have access to MWCC’s extensive containment network and systems. As of December 31, 2014, Apache’s investment in MWCC totals approximately $170 million.

Competitive Conditions

The oil and gas business is highly competitive in the exploration for and acquisitions of reserves, the acquisition of oil and gas leases, equipment and personnel required to find and produce reserves, and in the gathering and marketing of oil, gas, and natural gas liquids. Our competitors include national oil companies, major integrated oil and gas companies, other independent oil and gas companies, and participants in other industries supplying energy and fuel to industrial, commercial, and individual consumers.

Certain of our competitors may possess financial or other resources substantially larger than we possess or have established strategic long-term positions and maintain strong governmental relationships in countries in which we may seek new entry. As a consequence, we may be at a competitive disadvantage in bidding for leases or drilling rights.

However, we believe our diversified portfolio of core assets, which comprises large acreage positions and well-established production bases across five countries, our balanced production mix between oil and gas, our management and incentive systems, and our experienced personnel give us a strong competitive position relative to many of our competitors who do not possess similar geographic and production diversity. Our global position provides a large inventory of geologic and geographic opportunities in the five countries in which we have producing operations to which we can reallocate capital investments in response to changes in commodity prices, local business environments, and markets. It also reduces the risk that we will be materially impacted by an event in a specific area or country.

Environmental Compliance

As an owner or lessee and operator of oil and gas properties and facilities, we are subject to numerous federal, provincial, state, local, and foreign country laws and regulations relating to discharge of materials into, and protection of, the environment. These laws and regulations may, among other things, impose liability on the lessee under an oil and gas lease for the cost of pollution clean-up resulting from operations, subject the lessee to liability for pollution damages and require suspension or cessation of operations in affected areas. Although environmental requirements have a substantial impact upon the energy industry, as a whole, we do not believe that these requirements affect us differently, to any material degree, than other companies in our industry.

16

Table of Contents

We have made and will continue to make expenditures in our efforts to comply with these requirements, which we believe are necessary business costs in the oil and gas industry. We have established policies for continuing compliance with environmental laws and regulations, including regulations applicable to our operations in all countries in which we do business. We have established operating procedures and training programs designed to limit the environmental impact of our field facilities and identify and comply with changes in existing laws and regulations. The costs incurred under these policies and procedures are inextricably connected to normal operating expenses such that we are unable to separate expenses related to environmental matters; however, we do not believe expenses related to training and compliance with regulations and laws that have been adopted or enacted to regulate the discharge of materials into the environment will have a material impact on our capital expenditures, earnings, or competitive position.

17

Table of Contents