1

2018 Mid-Year Review

August 23, 2018

2

This presentation 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 prospectus 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 the Company in light of its experience and its perception of historical trends, current conditions and expected future developments, as well as other factors the Company believes are appropriate under the circumstances. However, whether actual results and developments will meet the expectations and predictions of the Company depends on a number of risks and uncertainties which could cause the actual results, performance and financial condition 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 the Group can complete on schedule pursuant to the terms and 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 risks and uncertainties, please see the documents the Company files from time to time with the United States Securities and Exchange Commission, including the Annual Report on Form 20-F filed in April of the latest fiscal year.

Consequently, all of the forward-looking statements made in this presentation 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.

Disclaimer

3

Overview

Operating Results and Highlights

Financial Performance and Analysis

Outlook

Agenda

4

Overview

Pursued progress in operation while ensuring stability with production in-line Put quality first and gave priority to performance, and

committed to high-quality development

8 new discoveries were made, with successful breakthrough in offshore China and overseas

two out of five new projects planned for 2018 already came on stream

Net production was 238.1 million boe*, in-line with expectation

Financial status maintained healthy and production costs remained excellent All-in cost of US$31.83/boe under effective cost control

Net profit of RMB 25.48 billion, EPS of RMB 0.57

Significant increase in free cash flow

Seize opportunity to increase investment and promote the key projects Proactively invest in world-class oil and gas projects

Vigorously promote major projects progress

Increase dividend payments: interim dividend HK$0.30 per share (tax inclusive) Focus on safety production and green development

*Including our interest in equity-accounted investees

5

1H 2018 1H 2017 Change%

Production (mm boe) 238.1 237.9 0.1%

- Crude and liquids (mm bbls) 194.1 198.2 -2.1%

- Natural gas (bcf) 256.9 231.4 11.0%

Realized oil price (US$/bbl) 67.36 50.43 33.6%

Realized gas price (US$/mcf) 6.42 5.68 13.0%

Oil & gas sales (RMB mm) 90,309 74,943 20.5%

Net profit (RMB mm) 25,477 16,250 56.8%

Basic EPS (RMB) 0.57 0.36 56.8%

Results Summary

Operating Results and Highlights

7

4,059

401

3D Seismic

Overseas

China - PSC

China - Independent

Exploration Activities

26

41

4

2

3

2

Wildcat Appraisal

*Excluding unconventional wells

Increased appraisal wells to accelerate the evaluation of oil and gas fields, and ensure reserve and production levels Success rate of independent exploration wells in offshore China reached 54-65%

4,460 (km2)

33

45

8

Exploration Achievements

Successful Appraisals

Discoveries

Bohai

Bozhong 19-6-3

Bozhong 19-6-4

Bozhong 19-6-5

Bozhong 19-6-6

Bozhong 13-1S-3d

Bozhong 13-1S-4d

Bozhong 13-1S-5d

Bozhong 13-1S-6d

Bozhong 29-6-2

Bozhong 29-6-3/Sa

Bozhong 29-6-4

Bozhong 29-6-6

Bozhong 29-6-7

Bozhong 29-6S-2

Bozhong 29-6S-3

Nanbao 35-2-A39H

Nanbao 35-2-A40H

Penglai 7-6-9

Kenli 4-1-2

Western South China Sea

Weizhou 11-12-3d

Weizhou 11-12-4d

Weizhou 11-12-7d

Weizhou 11-12-8d/Sa

Weizhou 11-12-9d/Sa

Weizhou 11-12-11

Weizhou 11-12-12d/Sa

Wushi 16-1W-5d

Wushi 16-1-7d/Sa

Ledong 10-1-6

Eastern South China Sea

Enping 10-2-2

Lufeng 14-4-4d

Xijiang 34-3-2

Lufeng 12-3-2

Discoveries

Guyana

Ranger

Pacora

Western South China Sea

Ledong 10-2

Weizhou 10-3E

Wushi 23-5N

Eastern South China Sea

Enping 10-2

Enping 15-2

Lufeng 12-3 Successful Appraisals

Guyana

Liza-5

Brazil

NW11

Offshore China

Overseas

6 new discoveries and 33 successful appraisal wells were achieved in offshore China Overseas, we made 2 new discoveries and 2 successful appraisal wells

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Two Discoveries of Hundred Million Ton-class in Bohai

Bozhong 29-6 to be a hundred million ton-class oil field

Located in Yellow River Mouth’s central sub-sag, with an average water depth of 23 meters

8 appraisal wells were drilled and encountered oil pay zones with average thickness of approximately 32 meters

Bozhong 19-6 to be a hundred million ton-class oil equivalent gas field

Located in the Bozhong Sag in Bohai, with an average water depth of 24 meters

Bozhong 19-6-1 was successfully drilled in 2017 and encountered oil pay zones with a total thickness of ~25 meters and gas pay zones of ~348 meters

6 wells have been drilled and appraisal will be completed by the end of October

Bozhong 19-6-4 achieved high test production recently, with an average of ~11 million cubic feet natural gas and ~1,900 barrels condensate oil per day, respectively

Proved to be a high abundance, high productivity and high quality gas field

Bohai

Bozhong 29-6

Bozhong 19-6

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Significant Exploration Breakthrough in South China Sea

South China Sea

Enping 15-1

Enping 10-2

Enping 15-2

Lufeng 12-3

New discovery of Lufeng 12-3 Located in Lufeng Sag in the Pearl River Mouth

Basin, with an average water depth of 242 meters

Discovery well Lufeng 12-3-1 encountered oil pay zones with a total thickness of ~36 meters

The largest commercial discovery under PSC in recent years and is expected to become a mid-size oil field

CNOOC Limited holds 60.8% of equity interest

New discoveries of Enping 10-2 and Enping 15-2 Located in Enping Sag in the Pearl River Mouth

Basin, with an average water depth of 87 meters

Discovery wells Enping 10-2-1 and Enping 15-2-1 encountered oil pay zones with a total thickness of ~54 meters and ~21 meters respectively

Proved the exploration potential of the northern part of Enping Sag and are expected to be jointly developed with Enping 15-1 and become a mid-size oil field

Note: According to the Regulation of Petroleum Reserves Estimation of

China, a mid-size oil and gas structure is defined as a structure with

recoverable oil resources of ≥2,500～＜25,000 thousand cubic meters.

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Liza

2015 2018

Payara Snoek Liza

Deep Turbot Ranger Pacora Longtail

0.8-1.4

2.25-2.75

3.2

4.0

New Discovery Increases Recoverable Resources to More than 4 Billion Oil- equivalent Barrels at the Stabroek Block Guyana

Huge resource potential

The first discovery within the Stabroek block was Liza,

made in 2015

8 successful discoveries have been made to date

Recoverable resources are estimated to be more than 4

billion boe

CNOOC Limited holds 25% interest Billion Boe

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155.8 152.9

82.1 85.2

0

150

300

1H2017 1H2018

China Overseas

237.9 238.1

Production in line with Expectation

(mmboe)

1H production reached 238.1 mmboe, in line with expectation.

2018 full year production target of 470-480 mmboe remains unchanged.

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1H 2018* 1H 2017*

Crude and Liquids

(mm bbls)

Natural Gas (bcf)

Total (mm boe)

Crude and Liquids

(mm bbls)

Natural Gas (bcf)

Total (mm boe)

China

Bohai 78.5 30.2 83.6 80.4 26.7 84.9

Western South China Sea 19.9 46.7 27.8 18.4 50.2 26.9

Eastern South China Sea 29.3 58.8 39.1 34.4 41.7 41.3

East China Sea 0.8 10.2 2.4 0.8 11.4 2.7

Others - 0.3 0.05 - - -

Subtotal 128.5 146.2 152.9 134.0 130.0 155.8

Overseas

Asia (Ex. China) 12.1 29.0 17.3 9.5 25.1 14.1

Oceania 0.7 17.3 4.0 0.4 14.1 3.2

Africa 11.9 - 11.9 14.2 - 14.2

North America (Ex. Canada) 9.2 23.3 13.1 8.4 22.9 12.2

Canada 11.3 6.5 12.4 9.0 7.9 10.3

South America 5.1 30.8 10.4 4.0 25.3 8.3

Europe 15.3 3.9 16.0 18.8 6.1 19.8

Subtotal 65.6 110.7 85.2 64.3 101.3 82.1

Total 194.1 256.9 238.1 198.2 231.4 237.9

* Including our interest in equity-accounted investees, which is approximately 10.6 mm boe in 1H 2018 and 8.4 mm boe in 1H 2017. In 1H 2018, production percentage of China and overseas was 64% v.s. 36%; Crude and liquids and natural gas was 82% v.s. 18%.

Production Summary

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Production Costs Remain Excellent, and Profitability Continuously Improved

39.82

34.67 32.54 31.83

51.27

41.40

52.65

67.36

0

10

20

30

40

50

60

70

2015 2016 2017 1H2018

All-in Cost Realized Prices

Utilize the oil price cycle to optimize the cost structure and continuously improve the profitability per boe

(US$/boe)

15

Intensify Exploration and Development Activities

50.1

70.0-80.0

0

20

40

60

80

100

2017 2018E

系列 1

In 2018, focus on both oil and gas development, substantially increase

Capex and accelerate investment in new projects

(RMB bn)

16

Two out of five new projects planned for this year already

commenced production and other projects proceed as planned.

New Projects in 2018

Project Location Status Expected Startup

Peak Production

(boe/d)

Working Interests

Stampede oil field United States Commenced production First half >40,000 25%

Weizhou 6-13 oil field Western South China Sea

Commenced production First half 6,300 100%

Penglai 19-3 oil field 1/3/8/9 comprehensive adjustment project Bohai Onshore

construction Second half 36,200 51%

Dongfang 13-2 gas fields Western South China Sea

Onshore construction Second half 43,400 100%

Wenchang 9-2/9-3/10-3 gas fields Western South China Sea

Installation and commissioning Second half 14,300 100%

* Production at Stampede continues to ramp up; designed capacity is 80,000 boe/d.

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Long Lake

Appomattox

Stabroek

Libra

Buzzard

Egina Uganda

Missan

Key Overseas Projects Progressed Smoothly

Egina: FPSO arrived at the production site, commenced commissioning

Uganda: FEED of upstream project completed and promote the negotiation of pipeline

Buzzard Phase II: Front-End Engineering Design(FEED) completed , Final Investment Decision(FID) approved in May

Missan: Increase production enhancement measures and promote new well drilling, production continues to ramp up

Long Lake: Continue to optimize the producing project, promote the K1A pipeline recovery, FID of LLSW project approved in April, the first tanker of bitumen has arrived in Huizhou

Appomattox: Offshore commissioning underway as scheduled

Stabroek: Continue to explore the resource potential，Liza Phase I development is progressing smoothly, FID of Liza Phase II is expected by the end of 2018

Libra: Single well production of Extended Well Testing (EWT) is 42,000 boe/day; FID of Mero1 has been approved, FPSO is under conversion in Dalian shipyard

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Overseas

Mero oil field

Egina oil field

Preowei oil field

Appomattox oil field

LLSW project

Meadow Creek oil sand project

Tangguh Phase II

Penglai 25-6 oil field 3 wellblock

Luda 29-1 oil field

Huizhou 32-5 comprehensive adjustment

Huizhou 33-1 oil field

Dongfang 1-1 gas field SE area/Ledong 22-1 south area

Wenchang 13-2 comprehensive adjustment

Wushi 17-2 oil fields

Wushi 23-5 oil fields

Lufeng oil fields

Liuhua 29-2 oil field

Liuhua 21-2 oil field

Liuhua 16-2/20-2 joint

development

Liuhua 29-1 gas field

Lingshui 17-2 gas fields

Luda 5-2N oil field

Nanbao 35-2 oil filed S1 area

Weizhou 12-8E oil field

Liza oil field Phase I

Liza oil field Phase II

Buzzard oil field Phase II

Kingfisher oil field

Tilenga oil field

Hokchi oil field

TT-3A oil field

New Projects to Support Production Growth

Offshore China

Luda16-3 oil field

Luda 21-2 oil field

Luda 6-2 oil field

Caofeidian 6-4 oil field

Caofeidian 11-1/11-6 comprehensive

adjustment

Qinhuangdao 33-1S oil field

Bozhong 19-6 gas field Phase I

Jinzhou 25-1 oil field 6/11 wellblock

19

Lingshui 17-2 Gas Project in South China Sea

First large-size deepwater gas field made by independent exploration in offshore China

Located in Lingshui sag in the deepwater area of Qiongdongnan Basin, with an average water depth of 1,450 meters

The discovery well Lingshui 17-2-1 was drilled successfully in 2014

Proved the exploration potential in deepwater area of Qiongdongnan Basin

Development and construction kicked off

The development project launched in June

The total investment is estimated at RMB20 billion

Designed capacity is 343 million cubic feet

It will accelerate the deepwater gas development in South China Sea and become the main driver of the Company’s gas production going forward

20

Lufeng Oil Fields in South China Sea

Located in Lufeng Sag in Eastern South China Sea, with water depth of 140-330 meters

Complete the feasibility study, will complete the basic design in April 2019 and start construction

3 producing oil fields, 4 appraisal oil fields, 1 redevelopment oil field

Joint development of new and producing oil fields to reduce cost

LF13-2 DPP

(Existing)

LF13-2 WHP

(Existing)

LF13-1 DPP

(Existing)

FSO

Existing Pipeline，15km

Existing flexible pipeline

to FSOU，1.7km

LF7-2 DPP

(Existing)

New Pipeline

23.8km

LF14-4 DPP(New)

LF22-1 SPS

(New) New Cable ，19km

LF15-1 DPP

(New)

New Cable，23.8km

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Accelerated the development of Liza Phase I

FID of Liza Phase I was sanctioned in July, 2017

17 development wells will be drilled

First oil planned in 2020, with peak production

expected to be 120,000 boe/day

CNOOC Limited holds 25% interest

Liza Phase II project

Plan the Liza Phase II and subsequent development

projects

Peak production of Liza Phase II is expected to be

220,000 boe/day

Peak production of the third phase is expected to be

180,000 boe/day

The collective discoveries to date have established

the potential for producing over 750,000 boe/day

Development at Stabroek Block in Guyana

22

Large-size deepwater field

Discovered in 2003, 130km away from Nigeria coast

Water Depth of 1,400 – 1,700 meters

Peak production of 200,000bbls/day

Stretch goal: first oil start at the end of 2018

CNOOC Limited holds 45% interest

Accelerate the construction and installation

FPSO arrived at the field site, commenced commissioning

Natural gas export riser was installed successfully

Subsea Production System: construction of all subsea

Christmas Tree was completed

The OLT was launched successfully and the

commissioning was finished

Egina Project in Nigeria

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Appomattox Project in USA

Key Facts

Located in the US Gulf of Mexico 130 km from

Louisiana

Water depth of 2,200 meters

FID announced in July, 2015

Interests: CNOOC 21%, Shell 79% (Operator)

Development Progress

The host platform and oil & gas flowlines have been

installed

Offshore commissioning operations are underway

Installation of the subsea infrastructure is in progress

Expected to commence production in late 2019, with

peak production of 175,000 boe/day

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Health, safety and environmental protection are always our top priority

OSHA statistics maintained at good level in the first half

1H 2018 1H 2017

Rate of Recordable Cases 0.08 0.10

Rate of Lost Workdays Cases

(per 200,000 man hours) 0.03 0.03

Health, Safety and Environment (HSE)

Financial Performance and Analysis

26

（RMB mm） 1H 2018 1H 2017 Change%

Revenue

Oil and gas sales 90,309 74,943 20.5% Market revenues 12,538 14,237 -11.9% Other revenue 2,802 3,182 -11.9% Revenue subtotal 105,649 92,362 14.4%

Expenses Operating expenses (11,610) (11,299) 2.8% Taxes other than income tax (4,245) (3,752) 13.1% Exploration expenses (2,260) (2,673) -15.5% DD&A (27,221) (31,824) -14.5% Special oil gain levy (1,117) - - Impairment and provision (159) (305) -47.9% Crude oil and product purchases (11,700) (13,538) -13.6% SG&A (3,135) (3,188) -1.7% Others (2,964) (3,698) -19.8%

Expenses subtotal (64,411) (70,277) -8.3% Profit/from Operating Activities 41,238 22,085 86.7%

Interest income 327 309 5.8% Finance costs (2,471) (2,704) -8.6% Exchange gains, net 254 294 -13.6% Investment income 1,675 1,063 57.6% Share of profits of associates 237 166 42.8% (loss)/profit attributable to a joint venture (6,509) 275 -2466.9% Other income, net 766 28 2635.7%

Profit before tax 35,517 21,516 65.1% Income tax expense (10,040) (5,266) 90.7% Net profit 25,477 16,250 56.8%

Key Financial Items - Consolidated

27

16,250

25,477

16,103

413

4,603 233 612

604

737

1,117 -

6,713

4,774

99.1% 4.5% 2.5%

28.3% 6.9% 1.4% 3.8% 41.3%

29.4%

3.7%

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

56.8%

Net profit rose significantly, mainly due to realized oil price increase and effective cost control.

Movement of Net Profit

(RMB mm)

28

396.0 380.0

134.3 132.3

122.7 105.0

471.6 478.4

144.0 110.9

37.4 28.0

Cash, cash equivalent and time deposits with maturity

over three months

Other Current Assets

Non-current Assets

Other Liabilities

Debt

Equity

(RMB bn) Jun. 30, 2018 Dec. 31, 2017

Movement of Financial Position

Total assets mainly include:

RMB391.9 bn of PP&E

Equity increased RMB16.0 bn:

Net profit of RMB25.5 bn

Dividend paid RMB11.3 bn

Currency translation differences, application of new standards, and other comprehensive income

*Gearing ratio = Interest Bearing Debt / (Interest Bearing Debt + Equity)

As at June 30, 2018 As at Dec 31, 2017

Total Assets (RMB bn): 653.0 617.2

Gearing Ratio*: 25.3% 25.8%

29

(人民币百万元)

14,059

23,480

58,406

1,865 1,500 918

21,222

28,998

2,456 592

-

10,000

20,000

30,000

40,000

50,000

60,000

70,000

Movement of Cash and Cash Equivalents

The balance of RMB37.2 bn resulted from net operating cash inflow and cash capex outflow was sufficient to cover debt repayment.

(RMB mm)

30

The Capex amounted to 21 billion in the first half of 2018, and investment is expected to accelerate in the second half of the year .

0.0

20.0

40.0

60.0

80.0

1H2017 1H2018 2018E

4.8 4.1

14.0 12.4

2.6 4.4

Exploration Development Production Other

70.0-80.0

21.0 21.4

Note: Above amounts exclude capitalized interest of RMB1.1 bn and RMB1.3 bn in 1H2017 and 1H2018 respectively

Accelerate Investment in 2H 2018

(RMB bn)

31

7.16 8.00

19.56 17.50

0.62 1.25 2.02 2.16

2.38 2.92

0

10

20

30

40

1H2017 1H2018

Opex DD&A Dismentalment SG&A Taxes other than income tax

31.83 31.74

In spite of oil price recovery and industry cost inflation, we maintained our cost competitiveness

Excluding the exchange rate impact, the all-in cost of 1H 2018 would be US$30.56/BOE

Maintained Excellent All-in Cost

All-in cost(US$/boe)

32

19.56 17.50

1H2017 1H2018

7.16 8.00

1H2017 1H2018

Cost Analysis

Opex

DD&A

Opex of US$8.00/boe, up 11.7% YoY.

Despite RMB appreciation against USD

and increase in raw materials and fuel

prices, Opex remains under effective

control

DD&A of US$17.50/boe, down 10.5%

YoY, mainly due to change in production

mix and increased reserve

(US$/boe)

(US$/boe)

33

(1) Based on closing share price of HK$13.12 as of July 31, 2018

(2) Exchange rate quoted as HK$1 = RMB0.86852 as of July 31, 2018

2018 interim dividend: HK$0.30 per share (tax inclusive)

An increase of HK$0.10 per share, or 50%, from 2017 interim dividend.

Dividend yield of 4.6%(1).

Interim dividend payment will be approximately RMB 11.63 billion(2),

representing about 8.5% of free cash at the end of July 2018.

Time arrangement:

Book close period: September 10 - September 14

Payment date: October 16

Dividend up 50% YoY

Outlook

35

Bohai will Stabilize Production at 30 Million tons in the Next 10 Years

Bohai acreage amounts to 45,700 square kilometers

76 oil and gas fields have been discovered and 45 in production

With the improvement of exploration degree, the amount of resources is

increasing

0

500

1000

1500

2000

2500

3000

3500

2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030

Future production plan of Bohai

(10k ton)

Producing oil field New oil field

Low permeability-marginal-heavy oil field

36

30 million ton level production for next 10 years

The Sustainable and High-quality Development of Bohai Oil Field

We pursue intrinsic safety and low carbon emission. We protect while developing and develop under the protection.

Action plan to enhance environmental protection

To stabilize the production of producing fields

To make progress on the development of low permeability, marginal, and heavy oil reservoir

To accelerate the development of new fields

Zero discharge of production wastewater

Zero record of blowout

Zero accident of oil spill pollution

37

169 179

193 206

237

260

289

320

0

50

100

150

200

250

300

350

2013 2014 2015 2016 2017 2018E 2019E 2020E

Natural Gas Demand Natural Gas Supply

(Billion cubic meters)

Strong Growth in Domestic Gas Demand Resulted in Undersupply

Develop low-carbon energy to protect the environment

Source: NBS, Morgan Stanley research report

38

Steady Increase in Natural Gas Reserves and Production

Gas reserves and production increase gradually

6,323 6,731 6,993

7,486 7,543

4,477 4,757

5,355 5,844 5,911

2013 2014 2015 2016 2017

CNOOC Limited Offshore China

Natural gas reserves in the last five years

220 223

2016 2017 2020 2025

(Thousand boe/day)

Production outlook of natural gas

(bcf)

39

Production target of 470-480 mmboe

Capex budget of RMB70-80 billion

Five new projects to come on stream in 2018

Reserve Replacement Ratio(RRR) > 100%

Maintain high standards on HSE performance

2018 Overview

40

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