RESPONSIBLE ENERGY DEVELOPMENT

ABOUT NEXENOIL SANDS / SHALE GAS & OIL / CONVENTIONAL OIL & GAS

ABOUT NEXEN: RESPONSIBLE ENERGY DEVELOPMENT

Nexen is responsibly developing energy resources in some of the world’s most significant basins including the UK North Sea, western Canada, the United States and offshore West Africa. As wholly-owned subsidiaries of CNOOC Limited, the Nexen group of companies employ approximately 3,200 people worldwide. Our team operates under clear value-based principles of excellence, personal accountability, integrity and social and environmental responsibility. It’s about getting the job done, the right way.

OUR CORE BUSINESSES

Nexen is strategically focused on developing and expanding three distinct yet complementary businesses – conventional oil and gas, oil sands and shale gas/oil. In 2013, Nexen contributed approximately 15% to CNOOC Limited’s total annual production.

CONVENTIONAL OIL & GAS

While Nexen has onshore production in Canada, the United States, Yemen and Colombia, the largest component of our conventional business occurs offshore. Over 50% of our production comes from offshore facilities in the UK North Sea, West Africa and Gulf of Mexico.

We’re a significant player in Canada’s oil sands industry. In 2013, our Long Lake facility continued to grow its production levels. We expect production rates will continue to increase as we bring Kinosis on-stream, a multi-phase, multi-year project to boost production. In addition, we have non-operating interests in the Syncrude Canada Ltd. mining and upgrading facility and the Hangingstone in-situ project.

OIL SANDS SHALE GAS/OIL

Shale gas is a clean-burning and abundant resource. We produce shale gas in northeast British Columbia, Canada. Nexen also manages working interests in two Chesapeake Energy shale projects in the U.S.

WE’VE COME A LONG WAY FROM OUR BEGINNINGS AS A SMALL CANADIAN EXPLORATION AND PRODUCTION COMPANY TO A LARGE DIVERSIFIED INTERNATIONAL COMPANY WITH WORLD CLASS ASSETS. NOW WE’RE PART OF AN EVEN MORE GEOGRAPHICALLY DIVERSE ENTITY FILLED WITH SIGNIFICANT OPPORTUNITY AND GROWTH. THE ACQUISITION BY CNOOC LIMITED MARKS AN IMPORTANT MILESTONE IN NEXEN’S HISTORY AND THE BEGINNING OF A VERY BRIGHT FUTURE.

ABOUT NEXEN 01

OUR APPROACH TO DOING BUSINESS

At Nexen, it’s not just what we do that matters – it’s how we get the job done. Health, safety, environmental and social responsibility are a foundational part of our workplace culture. Nexen’s stakeholders have diverse issues, interests and backgrounds and we strive to engage them fairly and openly. We are committed to giving back to the communities where we operate through charitable contributions and employee volunteering.

CNOOC LIMITED

CNOOC Limited is China’s largest

producer of offshore crude oil and

natural gas and one of the largest

independent oil and gas exploration

companies in the world, with

operations in more than 20 countries.

In 2013, CNOOC Limited produced an

average of 1.13 million barrels of oil

equivalent per day (boe/d).

From filling our gas tanks to heating

our homes, the energy Nexen

produces has a variety of uses.

Petroleum by-products are used to

create everything from cosmetics to

cell phones to shoes.

DID YOU KNOW?

NOW THAT NEXEN IS PART OF A MORE GLOBAL COMPANY, THE OPPORTUNITIES TO GROW MY SKILL SET AND EXPERTISE ARE EVEN GREATER. I AM EXCITED TO WORK FOR SUCH A DIVERSE COMPANY. MIKE MARKEVICH

ACCOUNTANT CRUDE OIL, MARKETING

OUR PURPOSE

We create value by responsibly supplying the energy that fuels people’s lives. The world needs clean, secure and affordable energy. We meet this need by harnessing our exceptional talent, world-class assets and progressive technology to find and develop oil and gas resources around the world. It’s our way of building a profitable, responsible business.

OUR STRATEGY

Nexen carries out CNOOC Limited’s strategy through:

LEADERSHIP ON RESPONSIBLE DEVELOPMENT

We earn and maintain our social licence to operate by working safely, responsibly and collaboratively with our stakeholders.

DIVERSITY

We maintain a diverse portfolio of assets, locations and commodity types to provide

flexibility through changing economic conditions and world events.

EARLY MOVER

We recognize opportunities early and acquire significant resource positions at low cost.

PARTNER ON LEGACY ASSETS

We develop strategic partnerships to invest in large scale assets that deliver attractive returns.

TALENT AND TECHNOLOGY

We leverage the expertise and innovation of our people to unlock technically complex energy resources.

SUPPORTED BY A STRONG BALANCE SHEET

A flexible balance sheet enables us to finance large capital projects through the economic cycle.

1970s WESTERN CANADIAN ROOTS

Nexen’s origins date back to the formation of Canadian Occidental Petroleum Ltd. (CanOxy), a Western Canadian oil and gas producer, in 1971.

1990s A WORLD-CLASS DISCOVERY

Our early success in Canada fuelled the company’s first international discovery in Yemen in 1990. It was a bold move that tripled our proved plus probable reserves and exceeded expectations by yielding more than a billion barrels of oil.

2000s DEVELOPING LEGACY ASSETS

CanOxy was renamed Nexen Inc. in 2000 and we embarked on our next growth phase by investing in the Buzzard offshore facility in the UK North Sea and our Long Lake oil sands operation.

2013 A NEW CHAPTER

A new chapter in our history began when CNOOC Limited acquired Nexen Inc. in a US$15.1 billion transaction. Calgary was established as CNOOC Limited’s head office for its North and Central American operations.

OUR STORY

Nexen’s roots may be in western Canada but today, as a wholly-owned subsidiary of CNOOC Limited, we operate on an international stage.

We embrace innovation and technology to responsibly and profitably develop resources in some of the world’s most significant basins. Most importantly, we’ve shown initiative and have built a company fuelled by deep talent and a passion for what we do.

02 ABOUT NEXEN

ABOUT NEXEN’S CONVENTIONAL OIL & GAS BUSINESS

UK NORTH SEA

Nexen is one of the largest oil producers in the UK North Sea, generating an average of 106,000 boe/d in 2013, which helps deliver 10% of the UK’s energy needs. We’ve more than doubled our proved reserves in the North Sea since 2004 and continue to actively explore in the region.

The Golden Eagle development is our next major UK project and one of the biggest oil discoveries in the region since 2004. First oil production is expected in late 2014 and the development is expected to have an initial gross production rate of up to 70,000 boe/d. Nexen will be the operator of this facility holding a 36.5% interest in the project.

OFFSHORE WEST AFRICA

Our deepwater Usan oil development project offshore Nigeria came on-stream in 2012. We are now actively exploring the region for future development projects.

GULF OF MEXICO

Nexen is one of the largest leaseholders in the deepwater Gulf of Mexico, considered one of the world’s most significant oil and natural gas basins. While our current business is relatively small – producing an average of 15,700 boe/d in 2013 – we’re actively exploring prospects with a primary focus on developing deepwater reservoirs.

EXPLORING IN THE DEEPWATER GULF OF MEXICO

In 2010, Nexen, along with our joint venture partner Shell Gulf of Mexico Inc., discovered Appomattox, located about 115 kilometers (72 miles) off the coast of Louisiana in approximately 2,100 metres (7,000 feet) of water. While development plans have not yet been finalized and remain subject to various internal and regulatory approvals, we are evaluating the construction of production facilities that would generate up to 200,000 boe/d, with provision for tiebacks of prospective discoveries in the area.

We’re also evaluating possible development alternatives with our project partners on the Stampede field, located about 270 kilometres (170 miles) southeast of New Orleans. Development at Stampede is subject to various internal and regulatory approvals.

CNOOC LIMITED ASSETS

As a result of the CNOOC Limited acquisition of Nexen, we now manage offshore oil and natural gas production from Trinidad and Tobago, onshore shale oil/gas production in the U.S., as well as exploration opportunities in the Yukon in northern Canada.

Conventional Oil & Gas

Shale Oil & Gas

Oil Sands

NEXEN IS A STRONG, DIVERSE COMPANY WITH ATTRACTIVE GROWTH PROSPECTS, A LARGE RESOURCE AND RESERVE BASE, HIGH-POTENTIAL EXPLORATION PROSPECTS, AND HIGH QUALITY TALENTED EMPLOYEES CAPABLE OF EXTRACTING THE VALUE OF THESE ASSETS. WE WILL THOROUGHLY UTILIZE THE PLATFORM IT PROVIDES TO FURTHER OUR OVERSEAS BUSINESS. LI FANRONG

CEO, CNOOC LIMITED

ABOUT NEXEN 03

UNDERSTANDING OIL SANDS TECHNOLOGY

Bitumen from Canada’s oil sands is recovered using two main methods:

About 20% of the resource is close enough to the surface to be mined using large trucks and shovels.

The remaining 80% can only be accessed through in-situ operations, most commonly using steam-assisted gravity drainage (SAGD) technology, which injects steam into the reservoir to thin the bitumen before pumping it to the surface. A relatively new innovation, in-situ offers an important environmental benefit: in-situ projects typically disturb about 85% less land than mining.

Nexen’s Long Lake oil sands facility in northern Alberta.

ABOUT NEXEN’S OIL SANDS BUSINESS

As an early entrant, Nexen recognized the long-term value of Canada’s oil sands: a secure and reliable source of energy. Canada is the largest energy supplier to the U.S. and close to half the crude oil exported from Canada is from the oil sands.

The Long Lake oil sands facility, which started up in 2008, is an integrated steam-assisted gravity drainage (SAGD) and upgrading operation southeast of Fort McMurray, Alberta. Long Lake has a production capacity of 72,000 barrels of bitumen per day (bbls/d) which, when upgraded, generates approximately 58,500 bbls/d of Premium Synthetic Crude oil. In 2013, we improved reliability and production rates. In order to operate at capacity, Nexen is pursuing a multi-phased, multi-year project to boost production, which includes plans to increase bitumen production through development at Kinosis, located about 12 kilometres south of Long Lake.

Development at Long Lake and Kinosis reflects only a portion of Nexen’s oil sands interests. We have a 7.23% interest in the Syncrude Canada joint venture that has been mining and upgrading oil sands deposits since the 1970s. Nexen also has a 25% non-operating working interest

in the Hangingstone SAGD project being developed by Japan Canada Oil Sands (JACOS), which is located about 50 kilometres southwest of Fort McMurray. CNOOC Limited has a 12.39% equity interest in MEG Energy, a Canadian oil sands developer.

Nexen is strategically positioned for future in-situ oil sands development, with land holdings in a number of Athabasca prospect areas including operated leases at Leismer and Cottonwood and non-operated leases at Meadow Creek, Corner and Chard.

INNOVATION AND COLLABORATION

Nexen is in the oil sands business for the long term. The key to our success is developing this large resource in a cost-effective and environmentally responsible manner. Innovation is essential and Long Lake is leading the way: our use of gasification technology takes a portion of the barrel that’s usually considered a waste by-product, transforming it into an energy source for our operations.

Nexen is a founding member of Canada’s Oil Sands Innovation Alliance (COSIA), an alliance of oil sands producers focused on accelerating the pace of environmental performance improvement. Launched in 2012, it offers a platform for unprecedented

collaboration on environmental matters by breaking down barriers in areas such as funding, intellectual property and human resources.

Through COSIA, Nexen is joining with other companies and leading thinkers from industry, government, academia and the public to address environmental performance in four key areas – tailings, water, land and greenhouse gases. We also work closely with our peers and other stakeholders to share information and best practices on topics such as energy efficiency, water use and reclamation.

WE WORK IN A CHALLENGING, AND AT TIMES CONTENTIOUS INDUSTRY. BUT I’M PROUD TO WORK FOR A COMPANY COMMITTED TO PRODUCING ENERGY IN A RESPONSIBLE WAY. DIANA CAROLINEZ GOMEZ,

PETROLEUM ENGINEER, COLOMBIA

04 ABOUT NEXEN

ABOUT NEXEN’S SHALE GAS/ OIL BUSINESS

The advent of new technology has enabled the cost-effective recovery of shale gas – a game-changing contribution to the world’s energy supply. Shale gas, which is found in abundance on many continents, is an affordable, cleaner-burning fuel that generates lower greenhouse gas emissions compared to other fossil fuels.

There are many benefits to shale gas production. This vast resource can be developed in small stages, which means we can control the pace of development and match production with economic conditions, market demand and other external factors.

AN EARLY MOVER

Nexen recognized the potential of shale gas early. In 2006, we began acquiring land in northeast British Columbia, Canada – a prolific shale gas region with excellent resource density. We began producing

gas in 2007 and continued to accumulate additional acreage in the nearby Cordova and Liard basins.

Our shale gas business is still in its early stages. Yet in a short time, we’ve accumulated industry leading technological expertise and driven down costs. Under a joint venture that was formed in 2012, INPEX Gas British Columbia Ltd. (IGBC) acquired a 40% working interest in our British Columbia shale gas properties.

Today, we hold over 300,000 acres of high-quality shale gas lands in the region.

Nexen also manages CNOOC Limited’s 33.3% working interest in two major U.S. shale projects operated by Chesapeake Energy: Eagle Ford (600,000 net acres in South Texas) and Niobrara (800,000 net acres in Colorado and Wyoming). The Colorado and Wyoming assets are primarily shale oil with some shale gas.

PROTECTING WATER SOURCES

Our operations comply with

rigorous protection measures for

water sources such as lakes, rivers

and aquifers. Our shale gas wells

have steel casing and cement

barriers in place to protect water

sources. Comprehensive water

monitoring is conducted and

the data collected is shared with

regulators. Nexen is also advancing

testing of new technology that

could enable us to use saline water

as an alternative to fresh water in

our shale gas operations.

A Nexen technician takes a water sample in northeast B.C.

ABOUT NEXEN 05

NEXEN’S LIQUEFIED NATURAL GAS STRATEGY

World trade in Liquefied Natural Gas (LNG) has grown dramatically over the last 15 years. Much of this increase is due to the expected growth in power generation using affordable, cleaner burning natural gas.

With a focus on safety, environmental responsibility, technical feasibility and costs, Aurora LNG is studying the viability of building and operating an LNG terminal on the coast of British Columbia. Our vision is to market and deliver clean-burning natural gas from shale gas assets in northeast British Columbia to growing Asia-Pacific markets where natural gas will assist Asia-Pacific countries in reducing their dependence on coal and nuclear energy.

The proposed LNG terminal will go through a comprehensive regulatory review process that will meet provincial and federal requirements. Project economics also need to be considered before a final investment decision is made.

Nexen’s Dilly Creek shale gas operations located in the Horn Basin in northeast B.C.

FORT NELSON

BC

N

AB

LIARD BASIN HORN

RIVER BASIN

CORDOVA BASIN

AURORA LNG

Aurora LNG is a joint venture

between Nexen Energy ULC and

INPEX CORPORATION. Aurora LNG

brings a wealth of proven experience,

expertise and well-established

relationships in all components of

the LNG value chain from: upstream

natural gas production; liquefaction;

transportation; regasification;

marketing; and, distribution of

natural gas to end users.

DID YOU KNOW?

The most efficient way to transport

natural gas by sea to markets around

the world is to convert natural gas

from its gaseous form to a liquid. An

LNG facility takes natural gas, purifies

it and cools it to -162 degrees Celsius.

Cooling natural gas to a liquid reduces

volume by 600 times – similar to

reducing the volume of a beach ball

to the volume of a ping-pong ball.

600xVOLUME REDUCED BY COOLING

NATURAL GAS TO A LIQUID

06 ABOUT NEXEN

IT’S ALL ABOUT OUR EMPLOYEES

We work hard to be an employer of choice in the highly competitive world of global energy exploration and production. We want to attract talented people and provide them with the resources and skills to share in our success.

Our employees work in a supportive culture that is designed to enhance collaboration, generate new ideas and encourage creative problem-solving.

Employees are given the opportunity to take an active role in mapping out a plan for their own career growth and development, supported by top-quality tools and resources supplied by Nexen.

Our pay-for-performance compensation programs are highly competitive and our comprehensive benefit, savings and pension plans provide value and flexibility to employees and their families. Flexible work schedules and volunteering days help employees balance work and personal lives.

At Nexen, we care about the way business is done. Our high standards of integrity and governance, along with our safe and responsible business practices, have earned us a global reputation for valuing the big picture: people, safety and the environment. Operating with integrity not only helps our performance, we believe it’s the best way to succeed.

Nexen is the recipient of many top employer awards and has been recognized for our training and skills development, employee engagement and community investment programs.

INVESTING IN NEW TALENT

We’re building our workforce capacity for the future. Nexen’s signature New Graduate Program hires young professionals in sought-after disciplines including engineering, finance and geology.

New grads undertake a series of assignments over three years to gain broad exposure to our business. They also have access to additional training, networking and mentoring opportunities – resulting in the development of highly trained and experienced young professionals ready to take on the challenges and opportunities that lie ahead.

Our New Graduate program has received many accolades and helped Nexen earn our standing among Alberta’s 65 Top Employers in 2014.

BEING PART OF THE NEXEN NEW GRAD PROGRAM IS A CHALLENGING AND REWARDING EXPERIENCE. THE COMPANY ENCOURAGES YOU TO GROW YOUR EXPERTISE BY ROTATIONAL WORK ASSIGNMENT, ON-THE-JOB TRAINING AND DEDICATED MENTORS. IT’S THE TYPE OF COMPANY I’M EXCITED TO WORK FOR. SEAN MARTIN-COURTRIGHT

CAPITAL ANALYST, CORPORATE PLANNING

Sean Martin-Courtright works with other new grads at Nexen’s Calgary office.

ABOUT NEXEN 07

NEXEN: INVOLVED IN OUR COMMUNITIES

Delivering safe and reliable energy in a socially responsible manner makes good business sense. It’s how we earn our social licence to operate and grow our business.

Nexen’s stakeholders have diverse issues, interests and backgrounds – and we strive to deal with them fairly and openly. We consult in various ways, including open houses, one-on-one meetings, community newsletters, and multi-stakeholder groups. We welcome feedback, track public complaints and follow up in a timely manner.

When Nexen operates on or near traditional lands of Canada’s Aboriginal peoples, we seek their input and share economic

benefits through employment opportunities, targeted training programs and by supporting Aboriginal businesses. We also provide training to Nexen employees and contractors to advance Aboriginal cultural awareness and understanding. Our commitment to Aboriginal relations and stakeholder engagement was recognized in 2012 when Nexen received Progressive Aboriginal Relations (PAR) certification at a silver level from the Canadian Council for Aboriginal Business.

INVESTING IN COMMUNITIES

Communities are at their very best when they enrich and inspire, educate and motivate and provide care to individuals and families who need it most. In 2013, Nexen contributed over $14 million to support communities where we operate globally. Through the three elements of Nexen’s ReachOut program we prioritize contributing to the communities where we operate so that communities and the people who live there thrive.

GIVING

In 2013, Nexen contributed $11.9 million to charitable, non-profit and community organizations. Our core funding areas are in education, arts and culture, community support and environmental protection.

MATCHING

Nexen matched a total of $1.8 million in employee and contractor contributions to charitable and non-profit organizations, reaching a new company record for 2013.

HELPING

Nexen employees took advantage of two days’ annual paid volunteer leave to contribute more than 14,000 hours of volunteer work to their communities in 2013. We also provided grants of $140,000 to charitable organizations and amateur sports associations in recognition of our employees’ volunteer efforts. In 2013, Nexen contributed approximately $700,000, also a new company record, through our employee volunteer program.

Our U.S. office supports a Habitat for Humanity initiative in the Houston area.

Employee volunteers at Pitcaple Environmental Project in Aberdeen, Scotland.

Nexen donated a digital piano to Chalo School in Fort Nelson and sponsored a free public recital with Honens Prize Laureate pianist Katherine Chi.

Nexen supports employees by

matching employee contributions

to registered charitable or non-profit

organizations up to a maximum

of $20,000 per individual in Canada

and the U.S. or £12,500 in the UK,

in any one calendar year.

Calgary employees help kick off Nexen’s 2013 United Way Campaign by building a billboard-sized puzzle wall.

08 ABOUT NEXEN

HEALTH, SAFETY, ENVIRONMENT & SOCIAL RESPONSIBILITY

Health, safety, environment and social responsibility are a foundational part of our workplace culture.

Nexen expects every employee and contractor working for us to return home safely and injury-free every day. To achieve this, we focus on fundamentals such as hazard identification and assessing the quality of our safety systems.

To help build a safe workplace, we’ve implemented Life Saving Rules that identify and address the relatively small number of actions that contribute to the majority of serious workplace incidents. Created from industry best practices, our Life Saving Rules strengthen our safety culture and are aimed at reducing high-potential incidents. Our ultimate goal is to eliminate workplace injuries – and we’re making progress. We have progressively reduced our injury rate over the past decade.

We complement this focus on personal safety with a drive to eliminate process safety incidents – the unplanned release of hazardous material that could result in harm to people, the environment or property. Nexen is also active in a number of industry groups focused on oil spill prevention and emergency response.

Members of our oil sands team work at our Long Lake SAGD oil sands facility.

SAFETY RULES AT NEXEN

Nexen’s 12 Life Saving Rules provide practical direction on safety expectations and what safe work looks like across our company. These rules are:

1. ALWAYS CONDUCT A HAZARD ASSESSMENT

2. ENSURE SAFE SYSTEMS OF WORK

3. FOLLOW THE MANAGEMENT OF CHANGE (MOC) PROCESS

4. ISOLATE ENERGY SOURCES

5. NO BREAKING OF CONTAINMENT WITHOUT A VALID WORK PERMIT

6. DO NOT ENTER A CONFINED SPACE WITHOUT AUTHORIZATION

7. WORK SAFELY AT HEIGHTS

8. CONDUCT SAFE LIFTING OPERATIONS

9. DRIVE SAFELY

10. ASSESS ALL GROUND DISTURBANCE HAZARDS

11. DO NOT WORK UNDER THE INFLUENCE OF DRUGS OR ALCOHOL

12. IGNITION SOURCES ARE NOT ALLOWED IN AREAS WHERE HYDROCARBONS MAY BE PRESENT

ABOUT NEXEN 09

Measuring stream flow in northeast B.C.

ENVIRONMENTAL STEWARDSHIP

We believe a combination of technology, process improvements and collaboration will drive continued environmental progress in our industry.

For Nexen, it starts with designing and building modern, energy-efficient facilities such as Buzzard and Long Lake. We then look for ways to reduce water use, energy consumption and waste – measures that also reduce operating costs. And finally, as a facility reaches the end of its life, we decommission and reclaim it in accordance with regulations.

As a technology-driven company, we see opportunities to harness technology for further environmental improvements. Long Lake, for instance, is designed to recycle more than 90% of produced water and capture up to 98% of sulphur dioxide emissions. We’re also researching technology solutions to reduce freshwater consumption in our operations.

AWARDS AND RECOGNITION

We’re proud of the awards and recognition we receive. They help us benchmark against other companies, confirming what we do well and where we need to improve. Most importantly, they reflect what we value – experienced and energized talent, high-quality disclosure, sound governance, responsible environmental stewardship and strong safety performance.

• Global 100 Most Sustainable Corporations in the World

• 2013 Corporate Knights

• Alberta’s Top 65 Employers 2014

• 2014 Mediacorp Canada Inc.

• Progressive Aboriginal Relations Certification – Silver Level

• Canadian Council for Aboriginal Business

VOLUNTARY REPORTING

Nexen has been voluntarily reporting our safety, environmental and social performance for more than a decade. See our sustainability data at www.nexencnoocltd.com/responsibledevelopment.

LEARN MORE

This publication summarizes Nexen’s operations, our strategy and how we work. But there’s much more to our story. Find out more at www.nexencnoocltd.com.

OUR COMMITMENT TO ABORIGINAL RELATIONS AND STAKEHOLDER ENGAGEMENT WAS RECOGNIZED IN 2012 WHEN NEXEN RECEIVED PROGRESSIVE ABORIGINAL RELATIONS (PAR) CERTIFICATION AT A SILVER LEVEL FROM THE CANADIAN COUNCIL FOR ABORIGINAL BUSINESS. GARY CRAG

PROCUREMENT MANAGER, CALGARY

10 ABOUT NEXEN

Golden Eagle – our next major UK oil development.

FORWARD LOOKING STATEMENTS

This report includes “forward-looking statements” within the meaning of the United States Private Securities Litigation Reform Act of 1995, including statements regarding expected future events, business prospects or financial results. The words “expect”, “anticipate”, “continue”, “estimate”, “objective”, “ongoing”, “may”, “will”, “project”, “should”, “believe”, “plans”, “intends” and similar expressions are intended to identify such forward-looking statements. These statements are based on assumptions and analyses made by Nexen Energy ULC (Nexen), a wholly-owned subsidiary of CNOOC Limited (the “Company”, NYSE: CEO, SEHK: 00883, TSX: CNU) in light of its or their experience and perception of historical trends, current conditions and expected future developments, as well as other factors that Nexen or the Company believes reasonable under the circumstances. However, whether actual results and developments will meet Nexen’s or the Company’s expectations and predictions depends on a number of risks and uncertainties which could cause the actual results, performance and financial conditions to differ materially from the Company’s expectations, including those associated with fluctuations in crude oil and natural gas prices, the exploration or development activities, the capital expenditure requirements, the business strategy, whether the transactions entered into by Nexen or the Company can be completed on schedule pursuant to its timetable or at all, the highly competitive nature of the oil and natural gas industries, the foreign operations, environmental liabilities and compliance requirements, and economic and political conditions in the People’s Republic of China. For a description of these and other risks and uncertainties, please see the documents the Company has filed from time to time with the United States Securities and Exchange Commission, including 2013 Annual Report on Form 20-F filed on April 17, 2014.

Consequently, all of the forward-looking statements made in this report are qualified by these cautionary statements. The Company cannot assure that the results or developments anticipated will be realized or, even if substantially realized, that they will have the expected effect on the Company, its business or operations.

All financial information in Canadian dollars.

August 2014

CONTACT

NEXEN HEAD OFFICE

801 – 7th Avenue SW

Calgary, AB T2P 3P7

Canada

T: 403.699.4000

www.nexencnoocltd.com

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The Usan deepwater oil development, offshore West Africa.