x Yes   o No

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, or a non-accelerated filer. See definition of “accelerated filer and large accelerated filer” in Rule 12b-2 of the Exchange Act. (Check one):

If an emerging growth company that prepares its financial statements in accordance with U.S. GAAP, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards† provided pursuant to Section 13(a) of the Exchange Act. o

† The term “new or revised financial accounting standard” refers to any update issued by the Financial Accounting Standards Board to its Accounting Standards Codification after April 5, 2012.

Indicate by check mark which basis of accounting the registrant has used to prepare the financial statements included in this filing:

If “Other” has been checked in response to the previous question, indicate by check mark which financial statement item the registrant has elected to follow.

(APPLICABLE ONLY TO ISSUERS INVOLVED IN BANKRUPTCY PROCEEDINGS DURING THE PAST FIVE YEARS)

Indicate by check mark whether the registrant has filed all documents and reports required to be filed by Section 12, 13 or 15(d) of the Securities Exchange Act of 1934 subsequent to the distribution of securities under a plan confirmed by a court. *

Unless otherwise specified, conversionsconversion of crude oil from tonnes to barrels are made at a rate of one tonne to 7.35 barrels for crude oil we purchase from external sources, one tonne to 7.10 barrels for crude oil we produced domestically and one tonne to 7.21, 7.20 and 7.21 barrels for the years ended December 31, 2015, 2016 and 2017, respectively for crude oil we produced overseas, representing the American Petroleum Institute (API) gravity of the respective source of crude oil.overseas. Conversions of natural gas from cubic meters to cubic feet are made at a rate of one cubic meter to 35.31 cubic feet; and 6,000 cubic feet of natural gas is converted to one BOE.

We publish our financial statements in Renminbi. Unless otherwise indicated, all translations from Renminbi to US dollars were made at the averages of mid-point exchange raterates of Renminbi as published by the PRC State Administration of Foreign Exchange (SAFE).

The following table sets forth the noon buying rate for US dollars in Renminbi for the periods indicated, as provided by the H.10 statistical release of the U.S. Federal Reserve Board. We do not represent that Renminbi or US dollar amounts could be converted into US dollars or Renminbi, as the case may be, at any particular rate, the rates below or at all. On April 13, 2016,20, 2018, the noon buying rate was RMB 6.47686.2945 to US$1.00.

This annual report includes “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. All statements, other than statements of historical facts, included in this annual report that address activities, events or developments which we expect or anticipate will or may occur in the future are hereby identified as forward-looking statements for the purpose of the safe harbor provided by Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. The words such as believe, intend, expect, anticipate, project, estimate, predict, plan and similar expressions are also intended to identify forward-looking statements. These forward-looking statements address, among others, such issues as:

·                  fluctuations in prices of our refined oil and chemical products,

·                  failures or delays in achieving production from development projects,

·                  potential acquisitions and other business opportunities,

·                  general economic, market and business conditions, and

·                  other risks and factors beyond our control.

Consequently, all of the forward-looking statements made in this annual report are qualified by these cautionary statements and readers are cautioned not to place undue reliance on these forward-looking statements. These forward-looking statements should be considered in light of the various important factors set forth above and elsewhere in this Form 20-F. In addition, we cannot assure you that the actual results or developments anticipated by us will be realized or, even if substantially realized, that they will have the expected effect on us or our business or operations.

ITEM 3.KEY INFORMATION

A.SELECTED FINANCIAL DATA

The selected consolidated statement of income data (except per ADS data) and consolidated cash flows data for the years ended December 31, 2013, 20142015, 2016 and 2015,2017, and the selected consolidated balance sheet data as of December 31, 20142016 and 20152017 are derived from, and should be read in conjunction with, the audited consolidated financial statements included elsewhere in this annual report. The selected consolidated statement of income data (except per ADS data) and consolidated cash flows data for the years ended December 31, 20112013 and 20122014 and the selected consolidated balance sheet data as of December 31, 2011, 20122013, 2014 and 20132015 are derived from our audited consolidated financial statements which are not included elsewhere in this annual report.

Moreover, the selected financial data should be read in conjunction with our consolidated financial statements and “Item 5. Operating and Financial Review and Prospects” included elsewhere in this annual report. Our consolidated financial statements are prepared and presented in accordance with International Financial Reporting Standards, or IFRS, as issued by the International Accounting Standards Board.

We consume a large amount of crude oil to produce our refined petroleumoil products and petrochemical products. Increases in crude oil prices may result in cost inflation, and high prices may also reduce demand for our products which might adversely affect our profitability. Decreases in prices of crude oil, refined oil products and refined product pricespetrochemical products may cause us to incur impairment to our investment and assets. A prolonged period of low oil price dropprices may impact our profit and ability to maintain our long-term investment projects. In addition, while we try to adjust the sale prices of our products to trackreflect international crude oil

Our ability to achieve our growth objectives is dependent in part on our level of success in discovering or acquiring additional oil and natural gas reserves. Our exploration and development activities for additional reserves also expose us to inherent risks associated with drilling, including the risk that no proved oil or natural gas reservoirs might be discovered. Exploring for, developing and acquiring reserves is highly risky and capital intensive. The fluctuation in the prices of crude oil and natural gas will impact the baseamount of our proved oil or natural gas reserves. In the low oil price environment, only large scale, high quality reserves meet our development criteria. Some exploration projects are not viable at the current crude oil price level and cannot be carried forward, potentially leading to failure in supplementing our oil and natural gas reserves with additional reserves through future exploration. Without reserve additions through further exploration and development or acquisition activities, or if the prices of crude oil and natural gas fall sharply, our reserves and production will decline over time, which may materially and adversely affect our results of operations and financial condition.

Exploring for, producing and transporting crude oil and natural gas and producing and transporting refined oil products and chemicalpetrochemical products involves a number of operating hazards. Our operations are subject to significant hazards and risks inherent in refining operations and in transporting and storing crude oil, intermediate products, and refined oil products and chemical products. These hazards and risks include, but are not limited to, natural disasters, fires, explosions, pipeline ruptures and spills, third-party interference and mechanical failure of equipment at our or third-party facilities, any of which could result in production and distribution difficulties and disruptions, environmental pollution, personal injury or wrongful death claims and other damage to our properties and the property of others. There is also risk of mechanical failure and equipment shutdowns both in general and following unforeseen events. In suchcertain situations, undamaged refinery processing units may be dependent on or interact with damaged process units and, accordingly, are also subject to being shut down. Even though we have a strong institutional focus on the safety of our operations and have implemented health, safety and environment (HSE) management system within our company with the view to preventing accidents, and reducing personal injuries, property losses and environment pollution, our preventative measures may not be effective. We also maintain insurance coverage on our property, plant, equipment, inventory and potential third party liability, but our insurance coverage may not be sufficient to cover all the financial losses caused by the operation risks and natural disasters. Significant operating hazards and natural disasters may cause interruption to our operations, property or environmental

There are numerous uncertainties inherent in estimating quantities of proved oil and natural gas reserves, and in the timing of development expenditures and the projection of future rates of production. Adverse changes in economic conditions, such as a prolonged period of low oil prices, may render it uneconomical to develop certain reserves and lead to downward revisions in our reserves. Our actual production, revenues, taxes and fees payable and development and operating expenditures with respect to our reserves may likely vary from these estimates.

The reliabilityestimate of reserves estimates depends on:

·                  the quality and quantity of technical and economic data;

·                  the prevailing oil and gas prices applicable to our production;

·                  the production performance of the reservoirs; and

·                  the production plans and etc.

In addition, new drilling, testing and production results following the estimates may cause substantial upward or downward revisions in the estimates.

Our oil and gas business is currently involved in exploration activities in various regions, including in some areas where natural conditions may be challenging and where the costs of such exploration activities may be high. As a result, our oil and gas business may incur cost overruns or may be required to curtail, delay or cancel drilling operations because of many factors, including, but not limited to, the following:

·                  unexpected conditions in drilling projects;

·                  irregularities in geological formations pressure;

·                  equipment failures;

·                  oil well blowouts;

·                  adverse weather conditions or natural disasters;

·                  compliance with existing or enhanced environmental regulations;

·                  governmental requirements and standards; or

·                  delays in the availability of drilling rigs and delivery and maintenance of equipment.

The future production of our oil and gas business depends significantly upon our success in finding or acquiring additional reserves and retaining and developing such reserves. If our oil and gas business fails to conduct successful exploration activities or to acquire or retain assets holding proved reserves, it may not meet its production or growth targets, and its proved reserves will decline as it extracts crude oil and natural gas from the existing reservoirs, which could adversely affect our business, financial condition and results of operations.

We have been actively pursuing business opportunities outside China to supplement our domestic resources. However, there can be no assurance that we can successfully locate sufficient alternative sources of crude oil supply or at all due to the complexity of the international political, economic and other conditions. If we fail to obtain sufficient alternative sources of crude oil supply, our results of operations and financial condition may be adversely affected.

Exploring, developing and producing crude oil and natural gas fields are capital-intensive activities involving a high degree of risk. Our ability to undertake exploration, development and production activities and make the necessary capital expenditures and investments is subject to many risks, contingencies and other uncertainties, which may prevent our oil and gas business from achieving the desired results, or which may significantly increase the expenditures and investments that our oil and gas business makes, including, but not limited to, the following:

·                  extent to which its ability to influence or adjust plans for exploration and development related expenditures is limited under joint operating agreements for those projects in which it has partners;

·                  government approvals required for exploration and development-related expenditures and investments in jurisdictions in which it conducts business; and

·                  economic, political and other conditions in jurisdictions in which it conducts business.

From time to time, we may construct new and/or revamp existing refining and petrochemical facilities, which require substantial capital expenditures and investments, thereinvestments. There can be no assurance that the cash generated by our operations will be sufficient to fund these development plans or that our actual future capital expenditures and investments will not significantly exceed our current planned amounts. Our inability to obtain sufficient funding for development plans could adversely affect our business, financial condition and results of operations.

Our development projects and production activities may be curtailed, delayed or cancelled for many reasons, including equipment shortages or failures, natural hazards, unexpected drilling conditions or reservoir characteristics, pressure or irregularities in geological formations, accidents, mechanical and technical difficulties and industrial action. These projects and activities, which include projects focused on non-conventional oil and gas exploration and development, will also often require the use of new and advanced technologies whichthat may be expensive to develop, purchase and implement, and may not function as expected. There is a risk that any development projects that we undertake may not yield adequate returns. In addition, our development projects and production activities, particularly those in remote areas, could become less profitable, or unprofitable, if we experience a prolonged period of low oil or gas prices or cost overruns.

As many nations in the international society has reachworld have reached consensus on the importance and urgency of addressing climate change, the oil and gas industry in which we operate is drawing increasing concerns about global climate change in recent years. A number of international, national and regional measures to limit greenhouse gas emissions have been enacted. The implementation of suchParis Agreement on climate change adopted by 195 nations in December 2015 has placed binding commitments on nations that have ratified it since November 2016, which may lead to more stringent national and regional measures in a number of countries and other potential legislation limiting emissions could affect the global demand for fossil fuels. If China or other countries in which we operate or desire to operate enact new laws that focus on limiting greenhouse gas emissions, itnear future. It could result in our substantial capital expenditure from compliance with these laws,measures, and our revenue generation and strategic growth opportunities could also be adversely impacted. In November 2014,addition, China and the United States made joint announcement against the threat of climate change, whereby China undertookhas undertaken to peak the CO2 emissions aroundby 2030 or earlier, if possible, and to increase the non-fossil fuel share of all energy to around 20 percent by 2030. FollowingChina has also implemented a national carbon emissions trading scheme in 2017, power generation industry has been included initially, and will gradually expand the pledge,industry coverage after the National Developmentmarket matures. We are recognized as an emission-control enterprise as are most of the Chinese enterprises, which could have adverse effect on our business, financial condition and Reform Commissionresults of China (NDRC) adopted the Provisional Measures on the Management of Carbon Emission Trading on December 10, 2014. In December 2015, 195 nations at the United Nations climate change conference in Paris adopted the Paris Agreement, for implementation after 2020. The Paris Agreement will place binding commitments on all signing parties and may lead to more stringent

We have operations and assets and may seek new opportunities in various countries and regions, including countries in Africa, South America and Central Asia and certain other regions, some of which are deemed to be subject to a high degree of political risk. These countries have experienced and/or may experience in future political instability, changes to the regulatory environment, changes in taxation and foreign exchange controls, frequent disease outbreaks, and deterioration in social security.security and environmental risks. Any of these conditions occurring could disrupt or curtail our operations or development activities. These events may in turnalso cause our production to decline, limit our ability to pursue new opportunities, affect the recoverability of our assets or cause us to incur additional costs, particularly due to the long-term nature of many of our projects and the significant capital expenditure required.

Depending upon the value of our assets, which may be determined based, in part, on the market price of our H shares or ADSs, and the nature of our assets and income over time, we could be classified as a passive foreign investment company, or PFIC, for United States federal income tax purposes. Based on our income and assets and the market price of our H shares or ADSs, we do not believe that we were a PFIC for the current taxable year ended December 31, 20152017 and do not anticipate becoming a PFIC or in the foreseeable future. Because PFIC status is a factual determination made annually after the close of each taxable year on the basis of the composition of our income and the value of our active versus passive assets for that year, there can be no assurance that we will not be a PFIC for any future taxable year. The overall level of our passive assets will be affected by how, and how quickly, we spendexpend our liquid assets. Under circumstances where gross income from activities that produce passive income significantly increase relative to our gross income from activities that produce non-passive income or where we determine not to deploy significant amounts of cash for active purposes, our risk of becoming classified as a PFIC may substantially increase. If we were to be or become classified as a PFIC, a US Holder (as defined in “Item 10. Additional Information –— E. Taxation –— United States Federal Income Tax Considerations”) may incur significantly increased United States income tax on gain recognized on the sale or other disposition of the H shares or ADSs and on the receipt of distributions on the H shares or ADSs to the extent such gain or distribution is treated as an “excess distribution” under the United States federal income tax rules. For more information see “Item 10. Additional Information –— E. Taxation— United States Federal Income Tax Considerations.”

Our results of operations are materially affected by economic conditions in China and elsewhere around the world. Although nations aroundThere are some uncertainty and instability in the world have adopted variouscurrent global economic policies to mitigate the negative influences caused by factors such as the slowdown of world economic development, it is uncertain how soon the world economy can be fully recovered.recovery. The Chinese economy has entered the “new normal” stage with more moderatestable and favorable economic growth .and is moving forward with high quality development. Our operations may also be adversely affected by factors such as someforeign countries’ trade protection policies which may affect the export and some regional trade agreements which may adversely affect the import.

Most of our revenues are attributable to sales of refined petroleumoil products and petrochemical products, and certain of these businesses and related products have historically been cyclical and sensitive to a number of factors that are beyond our control. These factors include the availability and prices of feedstock and general economic conditions, such as changes in industry capacity and output levels, cyclical changes in regional and global economic conditions, prices and availability of substitute products and changesfluctuation in consumer demand.prices and demands of natural gas, refined oil products and chemical products. Although we are an integrated company with upstream, midstream and downstream businesses, we have limited ability to mitigate the adverse influence of the cyclicality of global markets.

Among our competitors, some are major integrated petroleum and petrochemical companies within and outside China, which have recently become more significant participants in the petroleum and petrochemical industry in China. In 2015, theThe PRC government has gradually openedeased the restrictions on the right to use imported crude oil and relaxed control over the right to import refined oil products. This development may lead to refining overcapacity in China and intensify competition among local refineries. The relaxation of import control may drive up cost of crude oil imports and reduce the prices of refined oil products, thus adversely impact our refining margin. The Chinese crude oil and refined oil product markets are becoming increasingly dynamic and internationalized with implementation of tariff concessions and relaxation of market access as part of China’s commitment for its accession to the WTO. The potential trade conflict and increased trade protection measures implemented by several countries may adversely affect the production, trade or demand in petroleum and petrochemical industries, and may have a significant impact on our results of operations. In the wholesale market of cruderefined oil products previously dominated by PetroChina and refined petroleumus, we are facing stronger competition with new players and imported products entering the market. Our market share of chemical products is also under stronger competitive pressure due to the increasingly active participation of diversified new market entrantsplayers including local refineries. As a result,multinational petroleum and petrochemical companies and domestic private enterprises. In addition, we face more competition in both crude oil and refined petroleum product markets. We also expect to face competition in both domestic and international petrochemical product market as a result of our domestic and international competitors’ increasing production capacity. Increased competition may have a material adverse effect on our financial condition and results of operations.

We have engaged from time to time and will continue to engage in a variety of transactions with Sinopec Group, which provides us with a number of services, including, but not limited to, ancillary supply, engineering, maintenance, transport, lease of land use right, lease of buildings, as well as educational and community services. The nature of our transactions with Sinopec Group is governed by a number of service and other contracts between Sinopec Group and us. We have established various schemes in those agreements so that these transactions, when entered into, are under terms that are at arm’s length. However, we cannot assure you that Sinopec Group Company or any of its members would not take actions that may favor its interests or its other subsidiaries’ interests over ours.

Sinopec Group Company has interests in certain businesses, such as oil refining, petrochemical producing and overseas exploration and development, which compete or are likely to compete, either directly or indirectly, with our businesses. To avoid the adverse effects brought by the competition between us and Sinopec Group Company to the maximum extent possible, we and Sinopec Group Company have entered into a non-competition agreement. In 2012, we received from Sinopec Group Company an undertaking to avoid its competition with us. For details, please refer to the descriptions under “Item 7. Major Shareholders and Related Party Transactions –— A. Major Shareholders”. Notwithstanding the foregoing contractual arrangements, because Sinopec Group Company is our controlling shareholder, Sinopec Group Company may take actions that may conflict with our own interests.

Sinopec Group Company undertakes, from time to time and without our involvement, overseas investments and operations in the oil and gas industry, including exploration and production of oil and gas, refining and Liquefied Natural Gas or LNG, oilfield services and chemicalrefining engineering projects. Sinopec Group Company’s overseas asset portfolio includes oil and gas developmenta limited number of projects in Iran, Sudan and Syria, which countries that are targets ofsubject to U.S. sanctions administrated by OFAC and by the U.S. Department of State. In 2013, Sinopec International Petroleum E&P Hongkong Overseas Limited, a joint venture owned by Sinopec Group Company and us on an equal basis, acquired from Sinopec Group Company 49% interest in Taihu which is engaged in oil and gas exploration, development and production business in Russia. In December 2015, we acquired a 10% shareholding stake in PAO SIBUR Holding (Sibur Holding). Starting from 2014, OFAC imposed economic sanctions against Russia focusing on trading activities involving certain Russia’s financial and energy entities. We currently do not believe that our investment in Taihu and our 10% shareholding stake in Sibur Holdinginvestments will result in any direct sanctions imposed by OFAC. However, events in or relating to Russia, including further trade restrictions and other sanctions could adversely impact our investment in Russia.investments. In addition, the United States may expand its sanctions regime to include other countries or regions where Sinopec Group Company or its affiliates, including us, may have assets or operations.operations, or may unilaterally reinstate its sanction regime in Iran, where most U.S. secondary sanctions (i.e., those covering non-U.S. persons) have been suspended since January 16, 2016 pursuant to the terms of the Joint Comprehensive Plan of Action (the JCPOA), in the event of a dispute over Iran’s compliance with its nuclear commitments under the JCPOA. We cannot predict the interpretation or implementation of government policy at the U.S. federal, state or local levels with respect to any current or future activities by Sinopec Group Company or its affiliates, including us, in countries or with individuals or entities that are the subject of U.S. sanctions. Similarly, we cannot predict whether U.S. sanctions will be further tightened or reinstated in the case of Iran, or the impact that such actions may have on Sinopec Group Company and us. It is possible that the United States could subject Sinopec Group Company and us to sanctions due to these activities. Certain U.S. state and local governments and colleges have restrictions on the investment of public funds or endowment funds, respectively, in companies that are members of corporate groups with activities in certain countries that are the subject of U.S. sanctions. These investors may not wish to invest, and may divest their investment, in us because of our relationship with Sinopec

The PRC government, though gradually liberalizing its regulations on entry into the petroleum and petrochemical industry, continues to exercise certain controls over the petroleum and petrochemical industry in China. These control mechanisms include granting the licenses to explore and produce crude oil and natural gas, granting the licenses to market and distribute crude oil and refined petroleumoil products, regulating the upper limit of the retail prices for gasoline and diesel; collecting special oil income levies, deciding import and export quotas and procedures, setting safety, environmental and quality standards, and formulating policies to save energy and reduce emission; meanwhile, there could be potential changes to macroeconomic and industry policies such as reforming of the oil and gas industry, further improvement of pricing mechanism of petroleumrefined oil products, reforming and improvement of pricing mechanism of natural gas, and reforming in resource tax and environmental tax, which could impact our production and operations. Such control mechanisms may have material effects on our operations and profitability.

The PRC governmental authorities, from time to time, perform audits, inspections, inquiries or similar actions on state-owned companies, such as Sinopec Group Company, our ultimate controlling shareholder. Such inspections are not conducted on a regular basis with specific targets, and therefore we cannot predict the outcome of these governmental activities. If, as a result of such audits, inspections or inquiries, (i) material irregularities are found within Sinopec Group Company or us or our employees or (ii) Sinopec Group Company or we become the target of any negative publicity, our reputation, business and financial condition as well as the trading prices of our ADSs and H shares may be materially and negatively impacted.

As an integrated petroleum and petrochemical company, we are subject to extensive environmental protection laws and regulations in China. These laws and regulations permit:

·                  the imposition of environmental tax for the discharge of waste substances;

·                  the government, in accordance with law, to order correction, suspend production and impose fines for unlicensed or uncertified pollution discharge;

·                  the government, at its discretion, to seal up or close down any facility which has cause or may cause severe environmental damage and require it to correct or stop operations causing environmental damage; and

·                  litigations and liabilities arising from pollutions and damages to the environment and public interests.

Our production activities produce substantial amounts of liquid, gas and solid waste materials. In addition, our production facilities require operating permits that are subject to renewal, modification and revocation. We have established a system to treat waste materials to prevent and reduce pollution. However, the PRC government has moved, and may move further, toward more rigorous enforcement of applicable laws, and toward the adoption of more stringent environmental standards, which, in turn, would require us to incur additional expenditures on environmental matters.

In recent years, we have commenced exploration and production of unconventional oil and gas resources, such as shale oil and gas and coal bed methane, through the application of relatively advanced and expensive technologies. As a result, our unconventional oil and gas operations are subject to the limitations of unproven technology and expose us to

We are currently engaged in a number of construction, renovation and expansion projects. Some of our large construction, renovation and expansion projects are subject to governmental confirmation and registration. The timing and cost of completion of these projects will depend on numerous factors, including when we can receive the required confirmation and registration from relevant PRC government authorities and the general economic condition in China. If any of our key projects required for our future growth are not confirmed or registered, or not confirmed or registered in a timely manner, our results of operations and financial condition could be adversely impacted.

We receive a significant majority of our revenues in Renminbi. A portion of such revenues will need to be converted into other currencies to meet our foreign currency needs, which include, among other things:

·                  import of crude oil and other materials;

·                  debt service on foreign currency-denominated debt;

·                  purchases of imported equipment;

·                  payment of the principals and interests of bonds issued overseas; and

·                  payment of any cash dividends declared in respect of the H shares (including ADS).

The existing foreign exchange regulations have significantly reduced government foreign exchange controls for transactions under the current account, including trade and service related foreign exchange transactions and payment of dividends. Foreign exchange transactions under the capital account, including principal payments in respect of foreign currency-denominated obligations, continue to be subject to significant foreign exchange controls and require the approval of the State Administration of Foreign Exchange. These limitations could affect our ability to obtain foreign exchange through debt or equity financing, or to obtain foreign exchange. The PRC government has stated publicly that it intends to make the Renminbi freely convertible in the future. However, we cannot predict whether the PRC government will continue its existing foreign exchange policy and when the PRC government will allow free conversion of Renminbi.

The exchange rate of the Renminbi against the U.S. dollar and other foreign currencies fluctuates and is affected by, among other things, the changes in the PRC’s and international political and economic conditions. On July 21, 2005, the PRC government introduced a floating exchange rate system to allow the value of the Renminbi to fluctuate within a regulated band based on market supply and demand and by reference to a basket of foreign currencies. On June 19, 2010 and August 11, 2015, respectively, the People’s Bank of China (PBOC) decided to further promote the reform of exchange rate regime and enhance the flexibility of Renminbi exchange rate. Most of our crude oil purchases are settled in foreign currencies calculated on the basis of prices in U.S. dollar. Fluctuations in the exchange rate of the Renminbi against the U.S. dollars and certain other foreign currencies may adversely affect our oil and gas business, financial condition and results of operations. Meanwhile, pricesPrices of refined oil products are guided by the PRC Government and are pegged to the exchange rate of the Renminbi against the U.S. dollar. Therefore the impact of Renminbi exchange rate fluctuation on the purchase cost of crude oil could largely be offset by the corresponding fluctuation in the prices of domestic refined oil products and chemical products.

Currently, the primary sources of shareholder rights are our articles of association, the PRC Company Law and the Listing Rules of the Hong Kong Stock Exchange, which, among other things, impose certain standards of conduct, fairness and disclosure on us, our directors and our controlling shareholder. In general, their provisions for protection of shareholder’s rights and access to information are different from those applicable to companies incorporated in the United States, the United Kingdom and other Western countries. In addition, the mechanism for enforcement of rights under the corporate framework to which we are subject may also be relatively undeveloped and untested. To our knowledge, there has not been any published report of judicial enforcement in the PRC by H share shareholders of their rights under

China does not have treaties providing for the reciprocal recognition and enforcement of judgments of courts with the United States, the United Kingdom or most other Western countries, and therefore recognition and enforcement in China of judgments of a court in any of these jurisdictions in relation to any matter not subject to a binding arbitration provision may not be assured. Our articles of association as well as the Listing Rules of the Hong Kong Stock Exchange provide that most disputes between holders of H shares and us, our directors, supervisors, officers or holders of domestic shares, arising out of the articles of association or the PRC Company Law concerning the affairs of our company, are to be resolved through arbitration, at the election of the claimant, by arbitration organizations in Hong Kong or the PRC, rather than through a court of law. On June 18, 1999, an arrangement was made between Hong Kong and the PRC for the mutual enforcement of arbitral awards. This new arrangement was approved by the Supreme People’s Court of the PRC and the Hong Kong Legislative Council, and became effective on February 1, 2000. We are uncertain as to the outcome of any action brought in China to enforce an arbitral award granted to shareholders.

Our independent registered public accounting firm that issues the audit reports included in our annual reports filed with the SEC, as an auditor of companies that are traded publicly in the United States and a firm registered with the Public Company Accounting Oversight Board, or PCAOB, is required by the laws of the United States to undergo regular inspections by PCAOB to assess its compliance with the laws of the United States and professional standards. Because our auditor is located in China, a jurisdiction where PCAOB is currently unable to conduct inspections without the approval of the PRC authorities, our auditor, like other independent registered public accounting firms, is currently not inspected by PCAOB.

Inspections of other firms that PCAOB has conducted outside of China have identified deficiencies in those firms’ audit procedures and quality control procedures, which may be addressed as part of the inspection process to improve future audit quality. The lack of PCAOB inspections in China may prevent PCAOB from regularly evaluating our auditor’s audits and quality control procedures. The inability of PCAOB to conduct inspections of auditors in China makes it more difficult to evaluate the effectiveness of our auditor’s audit procedures or quality control procedures. As a result, investors may be deprived of the benefits of PCAOB inspections.

In December 2012, the SEC brought administrative proceedings against the “Big Four” accounting firms in China, including our independent registered public accounting firm, alleging that these firms had refused to produce audit work papers and other documents related to certain other China-based companies whose securities are publicly traded in the United States. On January 22, 2014, an initial administrative law decision was issued, censuring these accounting firms and barring these firms from practicing before the SEC for a period of six months. The decision is neither final nor legally effective unless and until it is endorsed by the SEC. In February 2015, each of the four PRC-based accounting firms agreed to a censure and to pay a fine to the SEC to settle the dispute and avoid suspension of their ability to practice before the SEC. The settlement requires the firms to follow detailed procedures to seek to provide the SEC with access to Chinese firms’ audit documents via the China Securities Regulatory Commission (CSRC) in response to future document requests by the SEC made through the CSRC. If the firms fail to comply with the documentation production procedures that set forth in the settlement agreement or if these required information fails to be provided to the SEC by the CSRC for reasons out of these firms’ control, the SEC could impose penalties such as suspensions, or it could restart the administrative proceedings.

In the event that the SEC restarts the administrative proceedings, depending upon the final outcome, listed companies in the United States with major PRC operations may find it difficult or impossible to retain auditors in respect of their operations in the PRC, which could result in financial statements being determined to not be in compliance with the requirements of the Exchange Act, including possible delisting. Moreover, any negative news about the proceedings against these audit firms may cause investor uncertainty regarding China-based, United States-listed companies and the market price of our ADSs may be adversely affected.

If our independent registered public accounting firm was denied, even temporarily, the ability to practice before the SEC and we were unable to timely find another registered public accounting firm to audit and issue an opinion on our financial statements, our financial statements could be determined not to be in compliance with the requirements of the Exchange Act. Such a determination could ultimately lead to the delay or abandonment of this offering, delisting of our ADSs from the New York Stock Exchange (NYSE) or deregistration from the SEC, or both, which would substantially reduce or effectively terminate the trading of our ADSs in the United States.

ITEM 4.INFORMATION ON THE COMPANY

A.HISTORY AND DEVELOPMENT OF THE COMPANY

Our legal and commercial name is China Petroleum & Chemical Corporation. Our head office is located at 22 Chaoyangmen North Street, Chaoyang District, Beijing 100728, the People’s Republic of China, our telephone number is (8610) 5996-0028 and our fax number is (8610) 5996-0386. We have appointed our representative office in the United States, located at 410 Park515 Madison Avenue, 6/F,Suite 27 West, New York, NY 10022, USA (telephone number: (212) 759-5085; fax number: (212) 759-6882) as our agent for service of processes for actions brought under the U.S. securities laws.

We were established as a joint stock limited company on February 25, 2000 under the Company Law of the PRC with Sinopec Group Company as the sole shareholder at our inception. Our principal businesses consist of petroleum and petrochemical businesses transferred to us by Sinopec Group Company pursuant to a reorganization agreement. Such businesses include:

·                  exploration for, development, production and marketing of crude oil and natural gas;

·                  refining of crude oil and marketing and distribution of refined oil products, including transportation, storage, trading, import and export of petroleum products; and

·                  production and sales of petrochemical products.

Sinopec Group Company’sGroup’s continuing activities primarily consist, among other things, of:

·                  exploring and developing oil and gas reserves overseas;

·                  operating certain petrochemical facilities;

·                  providing geophysical exploration, and well drilling, survey, logging and downhole operational services;

·                  manufacturing production equipment and providing equipment maintenance services;

·                  providing construction services;

·                  providing utilities, such as electricity and water; and

·                  providing other operational services including transportation services.

Sinopec Group Company transferred the businesses to us either by transferring its equity holdings in subsidiaries or by transferring their assets and liabilities. Sinopec Group Company also agreed in the reorganization agreement to transfer to us its exploration and production licenses and all rights and obligations under the agreements in connection with its core businesses transferred to us. The employees relating to these assets were also transferred to us.

From July 8, 2015 to expand our core businesses, prevent competition between us and members of Sinopec Group and reduce related party transactions, between 2001 and 2009 we have acquired Sinopec National Star Petroleum Company, Sinopec Group Maoming Petrochemical Company, Tahe Oilfield Petrochemical Factory and Xi’an Petrochemical Main Factory, certain Petrochemical and Catalyst Assets, certain Refinery Plants and certain service stations, certain Oil Production Plants, Sinopec Hainan and certain downhole operation assets, 100% equity interest of Sinopec Qingdao Petrochemical Company Limited and certain other assets relating to exploration and production, refining and marketing and distribution segments and assets of certain research institutes from Sinopec Group Company. We have also sold and disposed of certain auxiliary assets and chemical assets. In addition, we completed the privatization of Beijing Yanshan Petrochemical Co., Ltd. and Sinopec Zhenhai Refinery and Chemicals Co., Ltd. and the tender offers for the acquisition of

On October 29, 2015, we entered into a joint venture agreement with Sinopec Assets Management Co., Ltd. (“SAMC”), a wholly-owned subsidiary of Sinopec Group Company, undertakes notin relation to reduce its shareholdingthe formation of Sinopec Shanghai Gaoqiao Petrochemical Co., Ltd. (“Gaoqiao”). We and SAMC subscribed for 55% and 45% of the registered capital of Gaoqiao, respectively, and Gaoqiao became a subsidiary of the Company.

On August 2, 2016, our board of directors unanimously approved the proposal to introduce capitals from potential investors to invest in Sichuan-to-East China gas pipeline project, through our indirectly wholly-owned subsidiary Sinopec Sichuan-to-East China Natural Gas Pipeline Co., Ltd. (“Sichuan-to-East China Pipeline Co.”). On December 12, 2016, China Life Insurance Co., Ltd. (“China Life”) and SDIC Communications Holding Co., Ltd. (“SDIC Communications”) entered into the Capital Injection Agreement in relation to Sichuan-to-East China Pipeline Co. and agreed to collectively subscribe for 50% equity interest in Sichuan-to-East China Pipeline Co. for an aggregate amount of RMB 22.8 billion in cash. Upon completion of the capital injection, China Life, SDIC Communications and us hold 43.86%, 6.14% and 50% equity interest in Sichuan-to-East China Pipeline Co., respectively.

On April 27, 2017, our board of directors unanimously approved the proposal of the acquisition of equity interest in Shanghai SECCO Petrochemical Company duringLimited (“Shanghai SECCO”) by Gaoqiao. On October 26, 2017, Gaoqiao purchased 50% equity interest in Shanghai SECCO from BP Chemicals East China Investment Limited with a cash consideration of RMB 10,135 million. Before the Increase Periodacquisition, we and one of our subsidiaries held 30% and 20% equity interest in Shanghai SECCO, respectively. Upon completion of the statutory holding period.

We currently explore for, develop and produce crude oil and natural gas in a number of areas in China and overseas. As of December 31, 2015,2017, we held 202217 production licenses in China, with an aggregate acreage of 25,74831,498 square kilometers and with terms ranging from 10 to 80 years. Our production licenses may be renewed upon our application at least 30 days prior to the expiration date, which are renewable for unlimited times. During the term of our production license, we pay an annual production license fee of RMB 1,000 per square kilometer.

As of December 31, 2015,2017, we held 269211 exploration licenses in China for various blocks in which we engaged in exploration activities, with an aggregate acreage of approximately 857,421621,500 square kilometers and with the maximum term of seven years. Our exploration licenses may be renewed upon our application at least 30 days prior to the expiration date, with each renewal for a maximum two-year term. We are obligated to make an annual minimum exploration investment in each of the exploration blocks which we obtained the exploration licenses. We are also obligated to pay an annual exploration license fee ranging from RMB 100 to RMB 500 per square kilometer. Under the PRC laws and regulations, however, we are entitled for reduction and exemption of exploration license fee for exploration in the western region, northeast region and offshore of China.

As of December 31, 2015,2017, our overseas subsidiary held twoone production licenses, with an aggregate acreage of 323322.57 square kilometers. It currently does not have exploration licenses. Our overseas equity-accounted investments held 72 production licenses, with an aggregate acreage of 4,6604,783 square kilometers, and 5four exploration and licenses.

We currently operate 12 oil and gas production fields in China, each of which consists of many295 oil and gas producing fields and blocks.

Shengli production field is our most important crude oil production field. It consists of 7375 producing blocks of various sizes extending over an area of 2,5492,559 square kilometers in northern Shandong province, all of which are our net developed acreage. Most of Shengli’s blocks are located in the Jiyang trough with various oil producing layers. In 2015,2017, Shengli production field produced 192166 million barrels of crude oil and 16.1214.38 billion cubic feet of natural gas, with an average daily production of 535426 thousand BOE.

As of December 31, 2015,2017, the total acreage of our oil and gas producing fields and blocks in China was 10,82914,394 square kilometers, including 8,2678,528 square kilometers of developed acreage, all of which were net developed acreage; and 2,5625,866 square kilometers of gross undeveloped acreage, all of which were net undeveloped acreage.

As of December 31, 2015,2017, the total acreage of our oil and gas producing fields and blocks of our overseas subsidiary was 323322.57 square kilometers, including 169169.21 square kilometers of developed acreage, of which 30110 square kilometers were net developed acreage; and 153153.36 square kilometers of gross undeveloped acreage, of which 831.8 square kilometers were net undeveloped acreage.

As of December 31, 2015,2017, the total acreage of our oil and gas producing fields and blocks of our overseas equity-accounted investments was 1,7371,700 square kilometers, including 1,6241,628 square kilometers of developed acreage, of which 1,4841,628 square kilometers were net developed acreage; and 11372.4 square kilometers of gross undeveloped acreage, of which 11372.4 square kilometers were net undeveloped acreage.

As of December 31, 2015,2017, our estimated proved reserves of crude oil and natural gas in China were 3,160.32,425 million BOE (including 1,901.91,261 million barrels of crude oil and 7,550.76,985 billion cubic feet of natural gas), and our estimated proved reserves of crude oil and natural gas outside of China, which included a share of the estimated proved reserves of our equity-accounted investments, were 344.2340 million BOE. Our estimated proved reserves do not include additional quantities recoverable beyond the term of the relevant production licenses, or that may result from extensions of currently proved areas, or from application of improved recovery processes not yet tested and determined to be economical. There may be material changes to our proved reserves in connection with our discovery in exploration projects in the Fuling shale gas field after January 1, 2016.

The following tables set forth our proved developed and undeveloped crude oil and natural gas reserves by region as of December 31, 2015.