Status and challenges of Chinese deepwater oil and gas development

Pet. Sci(20118:47-484DOI10.1007/s12182011-0171-8Status and challenges of Chinese deepwateroil and gas developmentChen Wei*Research Institute, China National Offshore Oil Corporation, Beijing 100027, Chinao China University of Petroleum( Beijing)and Springer-Verlag Berlin Heidelberg 2011Abstract: There have been nearly 33 oil and gas fields with billions bbl resources found in deepwaterareas all over the world since 1970, so deepwater areas are of prime importance for petroleum explorationand development. With the achievements of a series of deepwater petroleum exploration technologyprojects in the USA, Europe and Brazil, the GOM, Brazil and West Africa are becoming the focus ofdeepwater oil and gas exploration. The oil productivity derived from deepwater areas exceeds that ofshallow water areas in GOM and Brazil since 2001. Deepwater is becoming very important for petroleumindustries and the top area of technology innovations. On the basis of analyses of world deepwatertechnological innovations, this paper briefly introduces the history of the China National Offshore OilCorporation(CNOOC), and then presents the status and challenges of Chinese deepwater oil and gasKey words: Deepwater, subsea production system, semi-submersible units, pipeline-laying barge, flow1 IntroductionLF22-l where the water depth (wD)exceeds 330 m weredeveloped with innovative deepwater technology, includingwith the rapid development of the Chinese economy in the subsea production system, semi-FPS and so on.Atthe last twenty years, the conflict between energy demands present, the deepwater exploration and development(E&D)and energy supply is increasing. Reducing the shortages of oil technology and deepwater vessels are being developedand gas is becoming more and more urgent. China's crude oil However, domestic technology and facilities for deepwaterproductivity has not met domestic market demand since 1993, oil development are still at a low level, perhaps 15 to 20 yearswhen China changed from a net oil-exporting country to a behind advanced world technology. So utilizing the deepwaternet oil-importer. In 2010, China's crude oil imports reached oil and gas as soon as possible is the most important task239 million tonnes and the shortage of oil is becoming a which is one of the best way to improve continuing energymajor factor constraining Chinas economic development In supply, and to solve the growing energy crisis in some extent2010, China overtook Japan to become the second highestil importer in the world, behind only the USA. From 2006, 2 World deepwater technology status anda series of national deepwater projects supported by the lIth trendsand 12th Five-Year Program have been going on, in orderto strengthen the exploration technology for developingdeepwater oil and gas resources.2.1 World deepwater oil and gas resourcesCNooC was founded in 1982. There are about 52Deepwater is a concept depending on technology leveloffshore oil and gas fields developed from Bohai Bay, Eastgenerally, the continental shelf deeper than 300 m is definedChina Sea to South China Sea. The oil and gas resources as the deepwater area for oil and gas development, and thosehave produced more than 50 million tonnes oil equivalent deeper than 1, 500 m are called ultra-deep waters(Zhang,and offshore oil and gas production has become one of major 2005). According to statistics in the Oil and Gas Journal,parts of Chinese oil and gas incremental production. The as of 1 January 2006, global offshore oil resources wereSouth China Sea, the largest sea area in China, is one of the 4 about 135 billion tonnes, and the proven reserves about 38largest oil and gas regions in the world. However, more than billion tonnes; offshore natural gas resources were about75% of remaining oil and gas reserves are in deepwater areas. 140 trillion cubieserves about 40From 1990, CNOOC began turning its eyes to deepwater trillion cubic met中国煤化工 At present,.galareas, and in 1996, 1997, the biggest oil fields LHIl-I and offshore proverCNMHGted by shallowwater reserves. Proven deepwater oil and gas reserves are*Correspondingauthoremailchenwei@cnooc.com.cnapproximately 10 billion tonnes oil equivalent, mainlyReceived October 10. 2011distributed in the U.S. Gulf of Mexico(GOM), the Brazil SeaPet. Sci(2011)8:477-484and West Africa. Since the 1990s, it is estimated there are are underway in the gOm, North Sea and Brazil since theclose to 100 global deepwater oil and gas reservoirs, among 1980s, in order to develop drilling and production units andwhich the reserves at the level of 100 million tonnes exceed technology for deepwater E&D. Through these systematic30%. In 2004 alone, global offshore oil and gas exploration studies great achievements have been obtained and the sixth-found 20 major deepwater reservoirs(Pan et al, 2006)with generation drilling facility which can operate in a waterreserves of over 100 million barrels, and now there are nearly depth of 3, 000 m has been built. Different kinds of deepwater3 huge discoveries in world deepwater areas(see in Fig. engineering technologies have been developed, there are1)(Li, 2006). According to the U.S. Minerals Management about 240 units of various types of deepwater floatingService(MMS)statistics, the Gulf of Mexico is one of the platforms such as CPT (compliant piled tower), TLP(tensionsingle largest suppliers of oil and gas to the U.S. market, leg platform), Spar(deep-draft single column platform)andwith continued interest and activity in deepwater areas of the Semi-FPS (large multi-functional semi-submersible platform)GOM, oil production will continue to be strong with a large are operated in world deepwater areas(seen in Fig. 3)portion of production coming from projects in deeper water Meanwhile, subsea production technologies have experienceddepth. Deepwater supplies about 70% of the oil and 36% of a rapid development there are over 6, 000 completed subseathe gas from the GOM. There are 7, 310 active leases in the wells. The world record depths change very rapidly, theU.S. GOM, 58% of which are in deepwater, respectively deepest offshore oil production is currently in a water depth(2009-2018 MMS 2009-012, Gulf of Mexico oil production of about 2, 743 m(the deepwater oil and gas research reportforecast to reach record high). Now deepwater is becoming 2010)and the longest tied back subsea production system isthe main area of offshore oil and gas development( Fig. 2). near 143 km. Now the petroleum industry has turned its eyesto a water depth of 3, 000 m Deepwater is the leading edge ofoffshore activity and technology innovationantsHowever there are still some deepwater challenges, asLow margin drilling conditionsHow to reduce well, flowline platform costs?Satarough 6 0idFig. 1 World deepwater oil and gas reservoir discoveries(after Li, 2006)35■■■国圆国■19961997199819992000200120022003200420052006Onshore c Shallow offshoreDeepwaterDeepwaterFig. 2 Offshore fields resources2.2 Deepwater technologyThe characteristics of deepwater oil and gas e&dinclude high risks, leading innovation technology and hugeInvestme中国煤化工The worlds first deep water exploration well wasCNMHsuccessfully drilled in 1970 in the GOM, the long-termnational research projects such as European PoseidonProject, Brazil PROCAP, PROCAP 2000, PROCAP 3000Fig. 3 Deepwater drilling rig and SPARsci(2011)8:477-484How to increase flow distances?How to minimize deepwater intervention costsHow to handle associated gas?How to develop deepwater marginaEnvironment risk3 Status of CNooC and Chinese deepwater3. 1 History of CNOOCSince cnooc was founded in 1982, about 52 offshoreil and gas fields have been developed from Bohai BayEast China Sea and South China Sea and these depend oninnovation and technology. Chinese fabrication time of aFPSO is a world record; the offshore anti-vibration platformfor sea ice had being successfully used in Bohai Bay and thelongest subsea pipeline which transports heavy oil and water,70 km was built in SZ36-1 oil fieldThe South China Sea, rich in oil and gas resources, isFig. 4 LF22-1 oil field development methodsone of the 4 world-renowned offshore oil and gas regionsA preliminary estimate of the geological oil resources in 3.2. 1 Advanced technology gapsthe deepwater totals 8.7 billion tonnes, with the expected The WD record of offshore drilling in the world is 3, 107 m,recoverableresourcesat2.7billiontonnesthegeological(http://www.physorg.com/news/2011-04-transocean-seanatural gas resources are expected to total 6.0 trillion cubic depth-oil-drilling html)and 1, 480 m in China; the WD recordmeters, with recoverable resources reaching 3.7 trillion for a developed field is 2, 743 m and only 333 m in China;cubic meters. Deepwater oil and gas discoveries in the South deepwater heavy-lifting and pipe-laying vessels can operate inChina Sea by adjoining countries(among others, the 864-m depths over 3, 000 m, and the biggest weight-lifting capacityMalampaya offshore oil and gas field and 350-m Linapacan reaches 14, 000 tonnes, while in China, offshore engineeringoil field in Palawan, Philippines; the 885-m Seno offshore equipment can operate only within 150 m, and the largestoilfield in East Kalimantan, Indonesia; the tectonic F6 Field weight-lifting capacity is only 3, 800 tonnes. Chinas deepestand Kikeh oil field offshore Sarawak, Malaysia) indicate oilfield is located in waters of 330 m operating with foreigngood prospects for oil and gas exploration in South China's partners. a huge technological gap has become a constraint todeepwater areas. The distribution of Chinas offshore oil China's deepwater oil and gas resources E&D( Liao and Cao,and natural gas are mainly in deepwater areas. In 1996, 2005). For China to reach intemational deepwater technologythe biggest oil field in the South China Sea, LHIl-I, was levels is a big but important challengedeveloped using 24 completed subset wells, a FPSO and a 3.2.2 Extreme environmental conditionssemi-FPS, 7 innovations had been used in this project, theFrequent typhoons in the South China Sea. Globallmost famous is subset ESP (electrical submersible Pump)and about 79 typhoons form each year, with the greatest andMEC(wet matble electrical connect)whose water depth strongest number occurring in the northwestem Pacific Oceanis 310 m. In 1997, the LF22-1 oil field, whose water depth is and South China Sea region. Between 1965 and 2008, this333 m was developed using 5 completed subsea wells and a area saw the formation of 1, 189 typhoons, an average of 27FPSO(seen in Fig. 4), which is the cost effective deepwater to 35 per year; more than half occurred in July, August andmarginal field development case. In 2006, the LW3-1-I well September, with most occurring in August.was successfully drilled, water depth is 1, 480 m, deepwater Maximum typhoon wind speeds can reach 120 knots(222gas field development is becoming a factkm/hr). The Hagupit Typhoon, which occurred in the South3.2 Challenges for Chinese deepwater development Fig. 5 shows a satellite photo. In 2006 the riser of the FPSoThe complexities of extreme environment conditions and used by the Lhll-l oil field was destroyed by Typhoonsthe geological conditions in the South China Sea bring largeTyphoons have resulted in great damages to offshorechallenges for the development of deepwater resources. The installations and are a principal hazard to offshore operationsmain challenges for China's deepwater oil and gas industry and platforms in the South China Sea. Serious damageeven leads to stoppage of oilfield production; stricter designShortage for deepwater technology, facilities and standards are under considerationexperienInternal wave. these are gravity waves that oscillateExtreme environmental conditionswithin a fluid m中国煤化工 rface. They ariseComplicated seabed topography;from perturbationDeepwater flow assurance due to complicated reservoir is maintained betImCNMHG, where balanceaw vI ay and the buoyantparametersrestoring force. A simple example is a wave propagating onDeepwater engineering and deepwater interventionthe interface between 2 fluids of different densities. suchPet. Sc(2011)8:477-484ridges can result in damage to offshore platforms, subseaequipments, pipelines and risers, and the likeEnvironmental conditions and design standard. In the2000s, because of the greenhouse effect, the frequency andintensities of severe environmental conditions have overcomethe established design standard. It is very important, indeednecessary, to revise existing deepwater engineering designstandards so as to counter extreme environmental conditionssuch as hurricanes, typhoons and the other extremely adverseonditions3.2.3 Complicated seabed topographyIn the South China Sea, the seabed landform is relativelysmooth and stable in shallow waters, but becomes veryFig. 5 Typhoon cloud satellite photo: Hagupit Typhooncomplicated and steep in deep waters. For example, thedistance of the 300-m water depth from onshore to offshore isas oil and water. Internal waves typically have much lower over 300 km, while the distance from 300 to 1, 500 m can befrequencies(or longer periods) and larger amplitudes than less than 60 kmsurface gravity waves.Complicated and steep seabed landforms will bring theInternal-wave flows with a maximum speed of 2 m/sfollowing disadvantages:occur very frequently in the South China Sea. Fig. 6 shows aUndulating seabed terrain can lead to a difficult pipelinetypical example.Internal waves also cause great damage to offshorea difficult pipeline route can cause serious flow-assuranceplatforms and subsea equipment.problems for a long tieback.Sand wave and sand ridge. There some moving"sandUndulating seabed terrain can result in increasedinvestment and more complex operations.hill"on the seabed. These form the most disastrous geologic 3.2.4 Deepwater flow assuranceThe current velocity of seabed reaches a maximum of 84Because of high static water pressure, low temperaturescm/s in the South China Sea; the velocity of a sand wave isthe composition of the fluids, long tieback distances the flowLike typhoons and internal waves, sand waves and below problem becomes even more serious, as shownestimated at 330 m/sassuranceGas hydrates will form in subsea trees, subsea pipelineand riser, and can result in hydrate blockages due to high fluidpressure and low temperatureSlugging is formed in flowline and riser because of steeplandforms and long tieback distances. Slugging can result in alarge pressure drop and may affect the process systemSolids such as wax, sand, asphalt and scaling are oftendeposited in subsea equipment and flowlines, and a high waxcontent in the crude oil and gas/condensate systems increasesthe risk of wax depositionCorrosion commonly occurs along the pipeline, greatlydamaging the equipment as well as the pipelineEmulsion will commonly occur in crude oil pipelines,ausing large pressure drops and affecting the process systemFig. 7 summarizes the deepwater flow-assurance problem4 CNOOC strategies for deepwater developmentChina aims to explore and develop oil and gas fields ata water depth from 1, 500 to 3, 000 m in the South ChinaSea before 2020, with production of 50 million tonnes oilequivalent from these deep waters. All those challengesand difficulties mentioned above shall have solutions in 10years, especiwaves, and tu中国煤化工 phoons, internaOC is carrying outcomprehensIHCNMHding deepwatera equipment and technologies. The specific objectives of theCNOOC deepwater development are as followsFig. 6 Typical intermal wave in the South China ScaDevelop offshore engineering facilities to build thePet. Sci(2011)8:477-484deepwater pipe recovery equipment, deepwater ditcher,Corrosiondeepwater subsea equipment, and DP-2/3 level dynamicpositioning system(weight-lifting/pipe-laying ). This vessel isFluidactio ThermodynamIcsto be in operation after 2011Phase II: 3, 000-m deepwater semi-submersible, heavy-WateSandlifting, pipe-laying vessel. The target operating waters of theplatform are the deepwater areas in the South China Sea,West Africa, the GoM. etc. Main dimensions are 220 m x 88m x 44 m; maximum operating depth is 3,000 m; maximumspeed is 15-20 km/day; and maximum weight-lifting capacityis 16,000 tonnes(dual cranes). The vessel uses the J-lay pipe-Fig. 7 Deepwater flow-assurance problemslaying mode, and the maximum diameter of the laying pipe isIndeepwater offshore shipping equipment4. 1.3 Deepwater geophysical survey vesselMaster 5 key technologiesThe first intermational, advanced deepwater geophysicalMaster 2 pioneering technologiessurvey vessel with 12 cables is to be developed in order toBuild a deepwater engineering construction yardhave deepwater large-area and high-precision 3-D seismicEstablish a deepwater engineering test basinacquisition capacities. The vessel will be 100-110 m long, 24-28 m wide, 9.5 m deep, with 16-knot design speed, unlimited4.1 Heavy facilitiesoperation zones, over 60 days endurance capacity, 5-knotDeepwater equipment is the basis for deepwater oil and speed, 12 x 8,000 m cable(spacing: 100 m), and 8 rankedgas E&D. In the past, China,s offshore oil and gas field gun arraydevelopment has been mainly focused on the shallow water 4.1.4 Deepwater engineering geological-survey vesselregion, and Chinas deepwater engineering equipment andA world-class deepwater(500-3, 000 m)engineeringsupporting fundamental technologies have been relatively geological-survey vessel is being developed. This vesselignored. Right now, the CNOOC's heavy investment is is 104-110 m long, 20 m wide, 9.5 m deep with 15-knotfocused on forming a 3, 000-m deepwater operational capacity maximum speed, and 16,000 nautical miles in endurancethrough the development of a deepwater semi-submersible capacity; it is self-sustaining for 70 days. Rigging capacitydrilling rig, a deepwater heavy-lifting pipe-laying vessel, is 3, 200 m(3,000-m WD plus 200-m hole depth),-200-+45a deepwater geophysical-survey vessel, a deepwater in adapting operating temperature,-4++35 in adaptingengineering-survey vessel, and a deepwater high-power water temperature. Through its dynamic positioning system,multi-functional supply shipthe vessel can carry out subsea geological drilling or seabed4. 1. 1 Deepwater semi-submersible drilling rigsurface sampling operations in 3, 000-m WD, 7-class wind,he HYSY-981(Offshore Oil 981)is the 6th-generation 3-m significant wave height, and 3-knot current speedadvanced deepwater semi-submersible drilling rig. Its main 4.1.5 Deepwater large-power multi-functional supply shipoperating areas are the South China Sea, but the rig willalso cover the deep waters in Southeast Asia, West Africa, is generally greater than 20,000 HP, and the mooring forceetc. The platform has both DP-3 dynamic positioning and is greater than 250 tonnes. The main service target is tomooring positioning functions, the maximum variable load operate as workboats of 500-600 tonnes' power, mainly foris 9, 000 tonnes, deepest operating water depth is 3, 000long-distance towing, deepwater anchor-lifting operations,ocean engineering support and other services. The plannedand maximum drilling depth is 10,000 m. It has drilling, deepwater large-power multi-functional supply ship is 93.4completion, testing and well-repairing functions. At present,the HYSY-981, first deepwater drilling rig in China, whichm long, 22.0 m wide, with 18-knot maximum speed, 3.0x10operate in 3,000 m water depth, and drill through 11,000tonnes in the biggest dolphin drag force, and 3, 030 km inhas been built and is to be in operation after 2011endurance capacity; it is self-sustaining for 60 days4. 1.2 Deepwater, heavy-lifting, pipe-laying vesselTwo kinds of vessels and the corresponding technologies 4.2 Five key technologiesare being studiedHere we discuss the 5 key technologies for South ChinaPhase 1: 3,000-m water depth (WD),heavy-lifting, Sea deepwater oil and gas development.ipe laying vessel By cooperating with gUSTO, a Dutch 4.2.1 Special environments of South China Seacompany, and by using its DPV7500 design as a mother ship,Forecasting and observation of the special environmentsthe design and construction of DPV7500C, a deepwater, in the South China Sea have been performed to supportheavy-lifting, pipe-laying vessel are completed. Main deepwater engineering design, installation and safe operation.dimensions are 204 m x 39 m x 14 m, using the s-type pipe- There has been中国煤化工 h on the internallaying method. The pipeline diameter varies from 6 to 60 in, wave formationteristics and itsand pipe-laying speed is about 5 km/day(48-in tube). Lifting mechanism witCNMHGp…as;, seabed- currentcapacity is of 4,000/3, 500 tonnes(stern fixed/full-rotary characteristics, the interaction mechanism of underwatermode). The vessel is equipped with stinger, lifting crane, biological attachments with structures, and the deepwaterpipe-laying operation system, deepwater piling equipment, geological survey.Pet. Sci.(2011)8:477-4844.2.2 Deepwater oil and gas field exploration technologies to better develop deepwater and marginal oil and gas fieldsThese have to be developed to carry out seismic especially when a long distance(300 km or more)from theacquisition and treatment at great depths, amid the difficulties shore, new equipment and innovative solutions, such aspresented by the continental slope and rugged seabed, and FLNG/FLPG and FDPSO, are essential. The floating liquidthe large size required of a single exploration-target reserve. natural gas( FLNGfloating liquid petroleum gas(FLPG)areLarge deepwater oil and gas basin slope accumulation theory the kinds of FPSo that can receive gas production offshoreand evaluation technology systems are very important in for processing, and liquefy the gas into LNG/LPG(Figproviding geological and geophysical technology support 8). The floating drilling production storage and offloadingfor the discovery of deepwater oilfields. Seismic imaging (FDPSO)is a kind of FPSO with drilling capabilities. Ittechnology breakthroughs in a rough seismic seabed shall also incorporates a design that is cost-efficient and effective forbe achieved, and scientific methods shall be proposed for the drilling and producing deepwater fields. Other new types ofdistribution prediction of marginal deepwater basin tectonic deepwater facilities, application technologies and supportingevolution, the thermal evolution of hydrocarbon source programs, etc are also being stressedrocks, the causes of far-source classic reservoir and formation The world's first FLPG, for operation offshore Angolaconditions, and large and midsized oil and gas fields in the started production in that country's SANHA offshore oilSouth China seafield on 14 November 2004, with a daily production capac-4.2.3 Deepwater geological reservoir engineering ity of 6,000 mand storage capacity of 135,000 m.Thetechnologyworld's first FDPSO (total cost is USS640 million), owned byLarge-scale reservoir identification and integrated Prosafe Production, left Keppel Shipyard in Singapore on 24interpretation and evaluation technologies are to be developed January 2009. However, due to the high cost and advancedfor the complex geological structures in deepwater areas, fine technologies, FLNG is not in production in the world; inimaging of complex structures, reservoir description, and recent years, it has been reported that it might possiblyoil and gas reservoir prediction. Analysis of oil geological become operational in a huge gas field in the Browse Basinconditions in deepwater areas and deepwater oil and gasmigration shall be performed for hydrocarbon accumulationResearch on gas traps containing oil, deepwater geologicalreservoir characterization and geological evaluation, andreservoir description, as well as the original geologicalreserves, evaluation technologies of technically recoverablereserves, etc, are to provide technical support to thedeepwater oil and gas reservoir development4.2.4 Deepwater drilling and completion technologiesFocused on the prediction of stratum drilling pressurein the deepwater region of the South China Sea, and onthe deepwater well structure optimization, drilling andcompletion technologies are to be developed for deepwatermud drilling systems, hydrate inhibitors and debris removal,and deepwater as well as shallow-level low-temperature well-cementing slurry systems. Studies are being carried out ondeepwater smart-completion technology, deepwater drilling(a) FLNG/FLPOand well control methods and techniques, deepwater subseadrilling equipment operation and monitoring technologydeepwater drilling wellbore pressure control and testingtechnologies. A deepwater drilling completion technologysystem is also set up to provide technical support for drillingand completion.4.2.5 Deepwater engineering technologyFocused on deepwater structure engineering, subseaproduction systems, flow assurance and such, deepwaterengineering technologies are studying the mobile securitycontrol of flows and hydrate risk-control, deepwatersubsea pipelines and risers, and the like. The Cnooc isplanning in the 12th Five-Year Program to initiate China'sfirst demonstration project of deepwater oil and gas fielddevelopment中国煤化工CNMHG4.3 Two pioneering technologies4.3.1 New deepwater equipment and innovative solutions(b) FDPSOTo hasten China's deepwater oil and gas exploration, andFig. 8 Schematic dagram for FLNG FLPG and FDPSoPet. Sci2011)8:47748448Western Australiaand Zhuhai construction yard, another deepwater fabricationFLNG/FLPG/FDPSO are most applicable when no is been built now. Its products will cover the whole of Chinapipeline network is available or if the distance from the shore for various shallow and deepwater oilfield projects, and alsois relatively long. The 3 new vessels can be most useful to radiate to various other markets, in Oceania, Southeast Asia,deepwater and marginal oil and gas field development in the the Middle East, West Africa, South America and elsewhereSouth China seaThe completion of the Qingdao construction site will lay4.3.2 Deepwater natural gas hydrate exploitation and a solid foundation for enhancing the manufacturing ability ofdevelopment technologythe CNOOC and for facilitating its march towards deepwaterNatural gas hydrates are ice-like cage-shape crystals operationgenerated from natural gas and water at a certain temperatureand pressure condition In natural gas hydrates, the gas is 4.5 Deepwater engineering test basinmainly composed of methane(90%). In standard conditionsThrough the deepwater engineering projects someI cubic meters of methane hydrate decomposition can deepwater lab facilities are built, such as deepwater test basin,produce 164 cubic meters of methane gas. Thus, natural gas multiphase flow loop with high pressure and low temperature,hydrates are considered to be a potentially important resource VIV equipment for subsea pipeline and riser.for the future. Earth is rich in natural gas hydrate reserves, The deepwater test basin( Fig 9)is built to provide thearound 20% of the land(most of which lies in the permafrost necessary research tools for deepwater technology research.layer)and 90% of the waters have natural gas hydrates( Sloan The main parameters of the basin are: Main body, 50 mand Koh, 2008). The land-based natural gas hydrates exist long x 40 m wide x 10 m deep; deep well, 40 m in depth;in the permafrost at a depth ranging from 200 to 2,000 m, maximum simulation water depth, 4,000 m.and under average ocean conditions, the water depth of the CNooC has signed strategic framework agreements withmethane hydrate formation ranges from 600 to 3,000 m, while outstanding universities and institutes, such as Shanghaithe stable depth of hydrates under seabed sediments ranges Jiaotong University and the China University of Petroleumfrom 0 to 1,000 m. Organic carbon in natural gas hydrates in order to establish a deepwater engineering and technologyis 53.3% of global organic carbon, which is twice the total research platform, to make great improvements in deepwatercarbon from coal, oil, gas and other fossil fuels(Li and Zeng, engineering technology by 20202011)and is one kind of promising clean energy. In May2007, gas hydrate samples were successfully collected frome northern part of the South China Sea. China is the fourthcountry after the United States, Japan and India to arrive atsuch a technological achievement. Initial estimates indicatethe potential volume of gas hydrates around the areascontinental slopes exceeds 100 million tonnes oil equivalentThe samples were collected from 2 different stationsthe Shenhu(Magic Fox) continental slope on 1 May an15 May 2007. At present, the cnooc has built a series ofexperimental facilities to physical simulating developmentLn tea bodom in回tmethods of Natural gas hydrateGas hydrate development methods can be divided broadlyinto 3 categories: depressurization, thermal stimulationand inhibitor injection. In the depressurization methodpressure of the fluids in contact with the hydrate is loweredby production, pushing the hydrate out of its stability regionand leading to its decomposition to methane and water(a)Schematic diagram of deepwater test basinIn the thermal stimulation method heat is introduced intothe reservoir, causing destabilization of the hydrate. Inthe inhibitor injection method, the injection of inhibitorscauses decomposition of the gas hydrate by shifting itsthermodynamic equilibrium curve. Most of these productiontechniques are conceptual and have not been tested on alarge scale. With the exception of the reported history of theMessoyakha field, reservoir tests for the production of gasfrom hydrates are in their infancy4.4 Deepwater engineering construction yardMV中国煤化工The Qingdao construction yard is one of the largestCNMHdeepwater fabrication yards in the world, which has the ability(b)Facility for riser and flow assurance experimental studyof processing 200,000 tonnes of structure steel at presentFig. 9 Schematic diagram of deepwater test platformPel. Sci(.2011)8:477-4845 Opportunities for Chinas deepwater6)Number of exploration wells: 619development7) Investment in exploration:1,691×10°RMB8)Production target: 50 million tonnes(oil equivalent)9)Investment in engineering equipment: 354x 10 RMB5.1 Huge deepwater oil and gas resources in South (not including supporting cost)China sea10)Investment in engineering yard: 301x10 RMBThere may be many deep submarine fans with excellent11)Total investment cost: over 3, 000x10RMBprospects for hydrocarbon exploration in the South ChinaTable I illustrates the CNoOC oil and gas productionrowth prospects in 2010 and the coming years.The deepwater area is estimated to be about 1, 540,000km, which is 75% of the total area; the oil geologicalTable 1 The CNOOC oil and gas production growth prospectsresource is 87x tonnes: the oil recoverable resource is(Unit: millions of tonnes)about 27x10 tonnes; the gas geological resource is 6.0x1020102020m; and the gas recoverable resource is about 3. 7x10mofshor55Domestic production5.2 Discovery of Lw3-1 deepwater gas fieldThe Lw3-1 deepwater gas field was discovered in JuneOverseas2006. It is in the Pearl River Mouth Basin, 250 km from ETotal production155Hong Kong. The first well was drilled at a water depth of 1, 480m Fig 10 shows the development plan of the Lw3-Igas 6 Conclusionsfield. At present, the LW3-l gas field will be developed usinga 10-well subsea production system, 79 km multiphase flow Chinese deepwater has potential gas-oil reserves, existingpipeline and shallow water platformopportunity and great challenges, with our best efforts, andextensive international technology cooperation, we can realizethe CNOOC's deepwater development objective, up to 2020is to be able to develop oil and gas fields in waters from 1, 500to 3, 000 m in depth and to reach 50 million tonnes of oilequivalent production, thus bringing the countrys deepwaterexploration and development technologies to the advancedworld levelIn near future. Chinese deewill be not only theleading edge of Chinese offshore activity, but also will havereached intermational standards of technologyReferences2009-2018 MMS 2009-012, Gulf of Mexico Oil and Gas ProductionForecast to Reach Record HighLiQ P and Zeng HY. The challenge of the natural gas hydratedevelopment. The Proceeding of the Unconventional GasFIg. 10 Development plan of Lw3-I deepwater gas fieldDevelopment Conference, Beijing, China, 2011LiQ P. Challenge of Chinese deepwater oil and gas exploration. China5.3 Exploration and development prospectsOffshore Oil and Gas. 2006. 18(2): 130-133(in Chinese)Liao M S and Cao L P. The gap of development of offshore oil industryThe Lw3-I gas field increases confidence in the discovery abroad and domestic and the proposal. Oil Field Equipment. 2005of even larger deepwater oil and gas fields in the South 34(2 ): 77-80(in Chinese)China Sea in the near future The CNooC will make many Pan J P, Zhang D W, Yue L Q, et al. Status quo of global offshore oimore investments in the exploration and development of and gas exploration and development and its trends. China Miningdeepwater oil and gas resources, and it will continuously seekMagazine. 2006. 15(11): 22-25(in Chineseinternational cooperation with more and more countriesSloan E D and Koh C A Clathrate hydrates of natural gases(thirdThe CNooC has formulated detailed prospects asedition). CRC Press. 2008followsThe Deepwater Oil and Gas Research Report 2010 (in Chinese)Tian H L and Yang J H. Status of and prospects for global deep-sea1)Deepwater blocks: 98 blocks and 0.36 million kmoil gas exploration and development. International Petroleum2)Contract blocks: 13 blocks and 0. 24 million km3)Potential resources: 1, 167x10 tonnes(oil equivalent) Zhang KHa中国煤化工。ore petroleum markct.4)Reserves targets: 19x10 tonnes(oil equivalent)OffshoreCNMHG5)Geophysical exploration: 2-D(17, 700 km), 3-D (3, 813km)(north of South China Sea(Edited by Sun Yanhua