Integrated Utilization of Offshore Oilfield Associated Gas

Transcription

1 Integrated Utilization of Offshore Oilfield Associated Gas ---Energy Saving ---Environment Protect ---Sustainable Effort CHINA NATIONAL OFFSHORE OIL CORP. September 18,

2 Operation Utilization Prospect CNOOC currently has several decades production oil & gas fields in offshore China. Among them, about 80% rich with associated gas. 2 2

3 Modes of Associated Gas Utilization As self-consumption fuel gas, used for generation and heat supply in oilfield operation; Collected and transported through subsea pipeline to Onshore Terminal for commercial purpose ; Gas injection to establish underground gas reservoir; Gas injection to improve the oil recovery ratio ; VOC Recovery. 3 3

4 China Offshore Associated Gas Resources Current integrated utilization situation of associated gas in CNOOC (million m 3 /d) Self-consumtion as fuel VOC recovery Gas injection Pipline collected for commercial purpose Vent 0 4 4

5 Self-consumption in Oilfield Equipment Set Consumption (m 3 /d) Cost-saving (USD/year) Turbine generator 79 2,300,000 80,500,000 Boiler ,000 22,500,000 The utilization of associated gas in oilfields generation and heat supply has greatly reduced the operation costs of the oilfields. 5 5

6 Pipeline Collected to Onshore Terminal FPSO Bonan oil and gas transfer project, located in Bohai Bay, China. Terminal 6 6 Meet the needs of electric and natural gas for surrounding residents after processed in Terminal. Volume of Gas to onshore terminal : 1,490,000m 3 /d.

7 Gas injection to Improve Recovery Ratio The right picture shows the Gas Injection Project in WZ12-1 Oilfield(located in South China Sea). By changing the oil driving mode with gas injection, the EOR up 8 %, showing considerable economic benefit. Platform with Gas-injection system Solved the high maintenance costs and low recovery ratio of the contaminated production well with when injected with water. 7 7

8 --- Project Initiation Focused on the philosophy of environmental protection and energy y saving, CNOOC initiated relevant study on Floating LPG Recovery. And firstly applied the research results to the LPG project in Wenchang oilfield (located in the South China Sea). Now the associated gas produced in the field reached Sm 3 /d, and C3+ taken up 53.35%.. Before the modification, the associated gas was discharged through torch burning,thus produced thick smoke and a large amount of greenhouse gas, and polluted environment. 8 8

9 ---Project Project Scale Added Skids LPG recovery skid Cooling water skid Offloading pump skid Offloading metering and residual fluid recovery skid Reel skid 4 Huge LPG tanks Net added weight :2600T Related facilities Modification 1.Modification of stern- transfer hydraulic system 2. Modification of heat media boiler 3. Modification of vent system height 4. Modification of pipeline in the process area 5.Removal of navigational lamps in starboard and port 6. Modification of cable tray in starboard 7.Structural installation of added hull and modules 8.Removal and modification of original hull structures 9.MCC revamp 9 9

10 ---Project Project Scale FPSO contrast before and after modification Before modification After modification 10 10

11 ---PFDPFD GAS TANKER OFF GAS INLET BLOWER INLET SCRUBBER INLET COMPRESSOR AFTER COOLER WARM TEMP SEPARATOR MOLE SIEVE DRIER FLARE FUEL GAS GAS/GAS EXCHANGER LOAD-OUT & FLOWMETER DEBUTANIZER REFLUX CONDENSER GAS GAS LPG LOAD- OUT HOSE&REEL DEBUTANIZER REFLUX ACCUMULATOR DEBUTA NIZER LIQUID COLD SEPARATOR ABSORBER CONDENSER ABSORBER WARM GAS CHILLER LPG SHIP LPG TANK PO PRODUCT LIQUID PROPANE REFRIGERATION SYSTEM 11 11

12 --- Difficulties & challenges Changeable weather and harsh construction environments; Cross disciplines and many a type of work thus leading to difficulties in technical integration; On-stream modification faced with immense production and engineering risks; Narrow FPSO space and difficulty in laying out equipment; Difficulties in Offshore LPG offloading; Lack of experience

13 --- Project Strategy Economical Safety first, People-oriented oriented Offshore on-stream modification optimize process system and ensure high recovery rate Utilize original auxiliary system and save investment The 420-day day- long modification realized a record of zero incident. On-stream modification scheme was the highlight of this project. It avoided vast output losses as a result of shutdown. Our sustainable improvements and optimization to the process system enhanced the recovery rate to 82%. Our modification and design used the related system of crude oil to the great extent. Not only benefit from solving the problem of narrow space on FPSO and hard layout, but also obviously saved the project costs

14 --- Technical innovation Innovation 1: Floating LPG Recovery Optimize the process system Used cool separator to replace conventional tower heat exchanger, lowered the height of absorbing tower and increased its capacity of anti- strong wind. Selected the type of tower Used filler tower to replace the conventional board-type tower so as to ensure the mass transfer efficiency and wind-proof capability. Optimized the filler section Added the overall height of the filler section in order that the mass transfer efficiency of the tower should produce quality LPG on condition that wind and wave has weakened

15 --- Technical innovation Innovation 2: Special waters stern-hanging offloading Tackling points Mooring method Offloading method Anti-static Offloading hose &Reel layout Recovery of offloading residual fluids Innovations Tandem mooring Single-line offloading Control the LPG flow velocity Hydraulic recovery Vacuum recovery 15 15

16 --- Technical innovation Innovation 3: Risk Control for Offshore On-stream modification Safety management obstacles Offshore changeable weather and frequent typhoon Many a discipline in cross design Many a type of work in construction and on-going at the same time. Variety, changeability and disaster in risks. Risks untraceable Safety management strategy Use internationally advanced risk techniques to assess the risks Establish perfected safety management system Techniques for risk control HAZOP (Hazard and Operability Study) FMECA STOP philosophy 6S site management QRA (Qualitative and Quantitative risk Analysis) 16 16

17 ---Project Project Achievements Environments C3+ components recovered from the torch gas have reached 82% plus, significantly reducing the pollution to environment, greatly reducing the discharge of greenhouse gas of ton per year. Energy-saving Annually recover 65,700 m 3 LPG,40150t condensate oil. The revenue can exceed 30 million USD

18 --- Project Achievements Torch contrast before and after operation After operation Before operation 18 18

19 --- Project Achievements Project Originalities Originated on-stream LPG recovery on FPSO The first FPSO having oil and LPG compound functions Technology breakthrough of LPG offloading for FPSO with single hose stern-hanging in specific sea area. Particular risk control techniques for offshore onstream modification 19 19

20 --- Project Achievements Significance of project popularization Under the present background of internationally initiating energy saving and environmental protection, the energy-saving and dischargeminimizing techniques explored and accumulated in this project have great significance of popularization. The exploration and practice of this project has provided a good example for developing international Oil & LPG FPSO standards and codes. Discovered a new way for offshore associated gas recovery and utilization

21 Expectations Technology Breakthrough Develop small-sized FPSO facility with compound LPG and LNG functions. Develop small-sized movable LNG and LPG storage and transportation devices; Transfer gas between work boat and production devices; Develop small-sized natural gas compressed skids; 21 21

22 Expectations Our objective To save energy and minimize gas discharge is the eternal subject and direction for CNOOC. In the next five years, with the adding of new oil fields and increasing of associated gas, CNOOC will make every effort to minimize the discharge of associated gas through sustainable technical tackling and related engineering and make our contributions to create a clean world! 22 22

23 Thanks!