Journal of Petroleum Science and Engineering Volume 41, Issue 1-3, Pages 1 – 7, 2004

DOI: 10.1016/S0920-4105(03)00138-4 Print ISSN: 09204105

Editorial An introduction to petroleum and natural gas exploration and production research in China

Zhijun Jin, Guoping Bai, G.Ali Mansoori (Affilations and addresses at the end)

1. History power of the ruling house and struggles for power among the regional powers. China is a huge country in eastern Asia. It is the In 221 B.C., Ying Zheng (259–210 B.C.), ruler of world’s most populous country with a population of the State of Qin and a man of great talent and bold 1.3 billion. Most of the Chinese people live in densely vision, established a centralized, unified, multi-ethnic populated areas in the eastern third of the country state in the Chinese history for the first time—the Qin where most of China’s major cities and nearly all the Dynasty (221–207 B.C.). He called himself Qin Shi farming land are located. About 36% of the people Huang meaning ‘‘First Emperor of Qin’’. He stan- live in regional cities and towns and the rest live in dardized the written scripts, weights and measures, rural areas. has 10 cities with a and currencies. More importantly, he set up a central- population of more than 3 million each in the urban ized government system and gave his country a area. They are Shanghai, (capital of the lasting ideal-national unity. The strong central gov- nation), Chongqing, Tianjin, Wuhan, Harbin, She- ernment structure was kept in some form by the nyang, Guangzhou, Chengdu and Nanjing (Fig. 1). following dynasties for the next 2000-odd years. He As one of the world’s oldest civilization, China has a mobilized over 300,000 people over a period of a written history of nearly 4000 years. The Chinese dozen years to build the Great Wall of China, which people take great pride in their nation’s long history. stretches for 5000 km in northern China. A fossil anthropoid unearthed in the town of The Qin Dynasty was succeeded by the Han Dy- Yuanmou in Yunnan Province, southwest China is nasty (206 B.C.–A.D. 220), Three Kingdom Period referred as ‘‘Yuanmou Man’’, who lived about 1.7 (220–265), Jin Dynasty (265–420), the Southern and million years ago and is China’s earliest primitive man Northern Dynasties (420–589) and Sui Dynasty known so far. ‘‘Peking Man’’, who lived in the (581–618). In 618, Tang Dynasty was established by Zhoukoudian area near Beijing 600,000 years ago, Li Yuan. Li Shimin, son of Li Yuan, adopted a series of was able to walk upright and could make and use liberal policies, pushing China’s feudal society to its simple tools. The Neolithic age started in China peak. Many historians consider the Tang period (618– approximately 10,000 years ago. Relics from this 907) the golden age of Chinese civilization. By 660s, period have been found all over China. China’s influence had extended to many city-states in The Xia Dynasty (family of rulers) was found in Central Asia. During this period, extensive economic 2070 B.C. Its activities were centered along the and cultural relations were established with a number Yellow River in the central China. The Xia Dynasty of countries including Japan, Korea, India, Persia and is the earliest known Chinese dynasty and was suc- Arabia. ceeded by the Shang Dynasty (1600–1046 B.C.) and The Tang Dynasty was followed by the period of the Western Zhou Dynasty (1046–771 B.C.). The the Five Dynasties and Ten States when almost following Spring and Autumn (770–476 B.C.) and continual warfare was prevalent. In 960, the Song Warring States (475–221 B.C.) saw the decline in Dynasty was established and lasted until 1279. In the Z. Jin, G. Bai, G.A. Mansoori An introduction to petroleum and natural gas exploration and production research in China J. Petrol. Sci. & Eng. 41(1-3):1–7, 2004 2

Fig. 1. Locations of China’s major basins and oil/gas fields.

Song Dynasty, China was in the front rank of the The succeeding ruled China from world in astronomy, science and technology. In 1271, 1368 to 1644. It was established in Nanjing by Zhu Kublai, a grandson of Genghis Khan, conquered the Yuanzhang. When his son Zhu Di took the throne in Central Plain, founded the Yuan Dynasty (1271– 1402, he built the palaces, temples, city walls and 1368), and make Dadu (today’s Beijing) the capital. moat in Beijing and officially moved the capital to During the Song-Yuan periods, the ‘‘four great inven- Beijing in 1421. The imperial palaces in Beijing’s tions’’ in science and technology by Chinese people in reached its current splendor largely ancient times—papermaking, printing, compass and through the efforts of Ming architects. gunpowder—were further refined and introduced to The Manchus of northeast China established the other countries, making great contributions to world (1644–1911) in 1644. Kangxi (reigned civilization. from 1661–1722) was the most famous emperor of the Z. Jin, G. Bai, G.A. Mansoori An introduction to petroleum and natural gas exploration and production research in China J. Petrol. Sci. & Eng. 41(1-3):1–7, 2004 3 period. He brought under Qing rule. He rein- transportation artery linking the west with the east. forced the administration of Tibet and effectively The Yellow River has a total length of 5464 km. Its administrated over 11 million km2 of Chinese Territory. valley is one of the birthplaces of ancient Chinese During the 19th century, the Qing Dynasty de- Civilization. clined rapidly and ended in 1911 when the revolution led by Dr. Sun Yat-sen overthrew the Qing Dynasty 2.2. Oil and natural gas exploration and production and established the Republic of China. Following several wars from 1924–1949, the Peoples Republic China is one of the first countries who discovered of China was founded in 1949. and used oil and natural gas. Historically, China led the world in technology on natural gas and salt exploration. The first oil well drilled by a rig was 2. Background recorded in Miaoli, Taiwan in 1878. On mainland China, the first oil well-Yan-1 was drilled in Yanchang 2.1. Geography , Shaanxi Province in the Ordos Basin) in 1907 and it discovered the first commercial oil field-Yan- Located in the east of the Asian continent, on the chang Field in China. From 1907 to early 1950s, few western shore of the Pacific Ocean, China has a land discoveries were made. In 1949 when the People’s area of about 9.6 million km2, trailing only Russia and Republic of China was founded, the national oil Canada. The territory of China spans over 49 latitudes output was only 120,000 tons (or 2400 bbl/day). Over from north to south and over 60 latitudes from east to the past 50 years, China’s petroleum industry has west. China extends over 5000 km both from north to made great progress and its domestic oil production south and from east to west. has been around 3.3 million bbl/day since 1996 but its China’s topography was completely formed around annual natural gas production has just passed through the emergence of the Qinghai–Tibet Plateau, which 1 trillion cubic feet (Tcf) because of its insufficient was uplifted over the past several million years due to pipeline infrastructure. the collision of the Indian and Eurasian plates. Taking From 1949 to the present day, four significant a bird’s eye view of China, the terrain gradually breakthroughs have been made in China’s oil and descends from west to east like a four step ‘‘staircase’’. gas exploration and production. The first break- The young Qinghai–Tibet plateau has an average through was achieved in late 1950s when the explo- elevation of over 4000 m above sea level and con- ration focus was shifted from the west to the east. It stitutes the top of the staircase. The second step has an was marked by the discovery of the Daqing Oil field, average elevation of 1000–2000 m and it includes the the largest field in China, in the Songliao Basin in gently dipping Inner Mongolia Plateau, the Loess 1959. This discovery indicates that nonmarine sedi- Plateau, the Yunnan–Guizhou Plateau, the Tarim ments were not only capable of generating oil but Basin, the Junggar Basin, and the Sichuan Basin could generate enough oil to form giant fields. The (Fig. 1). The third step, dropping to an elevation of second breakthrough was made in the Bohai Bay less than 1000 m, comprises the Northeast Plain, the Basin in 1960s and early 1970s when a number of North China Plain and the Middle–Lower Yangtze major oil fields were discovered. By 1978, China’s oil Plain from north to south. The continental shelf of output passed though the milestone of 100 million eastern China forms the fourth step of the ‘‘stair- tons per year (or 2 million bbl/day). The third break- case’’. Plains account for 35% of the total land area of through was made in late 1970s when the eastern China. offshore basins were opened for cooperative explora- China abounds in rivers. The rivers draining 1000 tion and production with foreign companies. Offshore km2 or larger areas are numbered more than 1500. oil and gas production has increased from 1800 The Yangtze and Yellow Rivers are the two largest barrels oil equivalent per day (boe/day) in 1982 to rivers in China. The Yangtze is 6300 km long, the 467,000 boe/day in 2001. The fourth breakthrough third longest river in the world, trailing only the Nile was achieved in late 1980s when the policy of in Africa and the Amazon in South America. It is a ‘‘Stabilizing the East and Developing the West’’ was Z. Jin, G. Bai, G.A. Mansoori An introduction to petroleum and natural gas exploration and production research in China J. Petrol. Sci. & Eng. 41(1-3):1–7, 2004 4 launched. Since then, numerous significant discoveries fields are estimated to hold proven in place gas have been made in the major basins in western China reserves of over 35 Tcf. Some natural gas from the including Tarim, Ordos, Junggar, Sichuan, Tu-Ha and Ordos Basin will be put into the West-to-East Pipe- Qaidam (Fig. 1). The current oil production in these line, which passes through the area and help make it basins is over 450,000 bbl/day. economically viable. A pipeline was completed in The current oil and natural gas exploration and 1997 between the Ordos Basin and Beijing, and a production in China are under auspices of PetroChina, second pipeline is planned in the near future, as which is the largest listed subsidiary of China National demand for natural gas in Beijing, Tianjin, and nearby Petroleum (CNPC), Sinopec (China Petroleum and Hebei province already is outstripping the capacity of Chemical) and the China National Offshore Oil the original pipeline. Another proposed pipeline proj- (CNOOC). PetroChina and Sinopec are responsible ect would link the Russian natural gas grid in Siberia for the onshore exploration and production whereas to China and possibly South Korea via a pipeline from CNOOC handles offshore exploration and production. the Kovykta gas fields near Irkutsk, which hold By the end of 1999, 460 oil fields and 162 gas fields reserves of more than 50 Tcf. The pipeline would had been found in China (Fig. 1). At the end of 2001, have a planned capacity of 2.9 billion cubic feet per China has a remaining proven oil reserve of about 24 day (Bcf/d). Aside from these huge projects, other billion bbls. PetroChina, Sinopec and CNOOC ac- pipelines are being developed to link smaller natural count for 64%, 21% and 15% of the China’s total gas deposits to other consumers. A pipeline was crude oil production of around 3.3 million bbl/day, completed in early 2002 linking the Sebei natural respectively. The oil reserves and production are gas field in the Qaidam Basin with consumers in the largely confined to four major basins: Songliao, Bohai city of Lanzhou. Another planned project would link Bay, Ordos, and Junggar Basins (Fig. 1). Oil produc- gas deposits in Sichuan province in the southwest to tion in the Songliao and Bohai Bay Basins makes up consumers in Hubei and Hunan provinces in central over 60% of the total domestic oil output. Recent China at an estimate cost of $600 million. onshore major oil discoveries have been made in the Offshore gas projects also are becoming a signif- Bohai Bay, Ordos and Junggar Basins. Recent off- icant part of China’s gas supply. The Yacheng 13-1 shore oil exploration interest has centered on the field, discovered in the Qiongdongnan Basin of the Bohai Sea area of the Bohai Bay Basin and the Pearl South China Sea in 1983, has been producing gas for River Mouth Basin. The giant Penglai 19-3 Oil Field Hong Kong and Hainan Island since 1996. It has a discovered by Phillips Petroleum in the Bohai Sea in proven in place gas reserves of 3 Tcf. The Chunxiao 1999 was one of the largest oil discoveries in 1990s in and three other gas fields in the Xihu Trough in the China. East China Sea are planed to be put into production in China’s domestic remaining proven reserves of 2004. The gas will be supplied to Shanghai through a natural gas is about 48.5 Tcf. The country’s largest subsea gas pineline of about 450 km. reserves of natural gas are located in the Ordos, Tarim, Sichuan and Qaidam Basins in central and northwest China (Fig. 1). Construction of PetroChina’s ‘‘West- 3. This special issue to-East Pipeline,’’ which will transport gas in the Tarim Basin to Shanghai and pick up additional gas Research activities on petroleum and natural gas in the Ordos Basin along the way, began in late 2002 exploration and production are undertaken by both and will be completed by end of 2004. The pipeline academia (universities and research institutions) and consists of nearly 3800 km, 1016-mm mainline and oil companies. The three national oil companies: 294 km of 813, 508 and 406 mm lateral lines. It CNPC, Sinopec and CNOOC all have their central eventually could serve as a trunkline which could be research institutes which undertake scientific research extended to receive gas from Central Asia. Over the related to their upstream activities. Universities and past 10 years, China have discovered five major gas research institutions attached to the Chinese Academy fields: Sulige, Qingbian, Yulin, Wushenqi and Mizhi of Sciences conduct both fundament research funded in the northern part of the Ordos Basin (Fig. 1). These by Chinese Ministry of Science and Technology and Z. Jin, G. Bai, G.A. Mansoori An introduction to petroleum and natural gas exploration and production research in China J. Petrol. Sci. & Eng. 41(1-3):1–7, 2004

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National Natural Science Foundation of China and with different approaches by taking timing of gas collaborative research with the three national oil charging, reservoir, trap and preservation conditions companies and their subsidiaries. into consideration. The presentations in this special issue represent the In the paper entitled ‘‘A preliminary study of wide range of current petroleum and natural gas mantle derived fluids and their effects on oil/gas exploration and production research activities in Chi- generation’’, Jin et al. present the features of mantle na, with papers in the areas of exploration, reservoir derived fluids and their effects on oil/gas generation in characterization, geofluids, petroleum migration and the Dongying Depression of the Bohai Bay Basin. accumulation, structural geology and production oper- Based on investigations of isotopic geochemistry, ations. The first contribution after this introductory organic geochemistry and thermodynamics, they dem- remark is authored by Guo et al. It is the biography of onstrate that hydrogenation by H-rich fluids derived late Professor Tian-min Guo, an international re- from the mantle likely occurred in the Dongying nowned expert in petroleum science and chemical Depression. The authors conclude that mantle-derived engineering. It summarizes his great achievements in fluids have important effects on hydrocarbon genera- his over 50 years teaching and scientific research. This tion as they provide both reaction energy and materi- special issue is to commend his contributions to the als, which has implications for the worldwide oil and petroleum science and engineering. The paper entitled gas exploration. ‘‘A review on the gas hydrate research in China’’ is The Dongying Depression is one of the most authored by late Professor Tian-min Guo et al. It gives petroliferous depressions in China. In this nearly an overview on the gas hydrate related research in 6000 km2 depression, 34 oil/gas fields have been China over the past decade in the areas of basic found with proven in place oil reserves of 15 billion research, status of the exploration of natural gas bbl. The oil/gas habitat of the depression is presented hydrate resources in South China Sea and develop- in ‘‘Oil/gas distribution patterns in Dongying Depres- ment of hydrate-based new technologies. The authors sion, Bohai Bay Basin’’ authored by Li. A complex conclude more and more Chinese institutions will be structural framework resulted in the formation of involved in this type of research and abundant gas complex reservoirs and different trap types, which in hydrate resources will be likely to be found with the turn led to different oil/gas distributions in different improvement of research capacity in the next decade. structural trends in the depression. More importantly, The paper by Song et al. documents the types of the the paper concludes that great exploration potential geochemical characteristics of four types of natural still exists in this depression in spite of its 40 years gas (coal-formed cracking gas, coal-formed thermal exploration history. The following paper by Zhang gas, oil-type thermal gas and mixed gas) and features illustrates how to apply an integrated approach to of gas reservoirs in the China’s foreland basins. It explore lacustrine turbidites in Jiyang Sub-basin of further discusses the source rock intervals for each of the Bohai Bay Basin. The techniques involve an the four types of gas in different foreland basins. One integration of multi-disciplinary approaches of se- of their main findings is that abnormally high pres- quence stratigraphy, seismic velocity data analyses sures are widely developed in these foreland basins and an optimization process. The application of these and natural gas accumulations are characterized by techniques in the lacustrine basin setting has been multiple source rock-reservoir-seal combinations. The proved to be quite successful as approximately 438 next paper by Wang also deals with natural gas in million bbls of proved in place oil reserves were China. It illustrates how to classify Chinese gas fields discovered from 1996 to 2001 in turbidite reservoirs into four types in terms of timing and gas charging in the Jiyang Sub-basin. These techniques can be and entrapment. Accumulation model and character- probably used in other lacustrine basins in the world. istics of each of the four types are clearly documented The paper by Pang et al. documents the oil and gas with field examples in different basins in China. His migration and accumulation models in the Qaidam studies indicate that almost 50% of Chinese gas fields Basin. Continuous permeable sandstones, faults and are characterized by gas chagrining and entrapment in fractures constitute the main migration pathways. In Cenozoic times. Gas exploration should be carried out different parts of the basin, the main migration path- Z. Jin, G. Bai, G.A. Mansoori An introduction to petroleum and natural gas exploration and production research in China J. Petrol. Sci. & Eng. 41(1-3):1–7, 2004 6 ways are different. Along the basin margins hydro- reflections. This new technique is developed by com- carbons accumulate in sandstone reservoirs whereas bining experimental results of seismic physical mod- not only sandstones but also fractured mudstones eling in the laboratory with the Biot theory. Sandstone comprise reservoirs in the basin interior. The paper reservoirs can be directly detected with the reflection concludes that each of the four models proposed can amplitude attenuation characteristics. They conclude be used to target different prospects in the basin. that this technique has been successful in finding oil The next three papers are all on the Tarim Basin. and gas reservoirs in the central western China. It may Tang et al. illustrate how salt structures were evolved be applied to other basins of the world. and how they controlled oil/gas accumulation in the The paper entitled ‘‘Measurement and corr- Kuqa foreland belt. The Lower Tertiary salt sequence esponding states modeling of asphaltene precipitation divides the Moso-Cenozoic strata into three tectono- in Jilin reservoir oils’’ is co-authored by researchers sequences. They conclude that the subsalt sequence from three institutions involving University of Petro- are the favorable places for hydrocarbons to accumu- leum, CNPC’s Research Institute and University of late as source rocks are largely confined to the subsalt Illinois at Chicago. In the paper, Zhao et al. present sequence and salt beds can act as excellent cap rocks. their experimental results for the asphaltene precipita- The paper by Lu et al. deals with oil and gas tion for two oil samples under pressure and with/ accumulations in the Ordovician carbonates in the without CO2-injections. Based on the results, they Tazhong Uplift, which, together with the Tabei Uplift, propose a generalized corresponding states principle hosts most of the discovered oil and gas fields in the (CSP) to predict asphaltene precipitation. The pro- Tarim Basin. In the Tazhong Uplift, oil and gas were posed CSP theory is a comprehensive model which locally sourced. Oil and gas migration is characterized embodies previous specialized modelings in this field by a short lateral migration through sand bodies and of research. They conclude that the theory is capable of unconformity surfaces and a vertical migration by extending to correlate/predict the asphaltene precipi- faults. The paper concludes that the northern slope tation in the high-pressure CO2-injected reservoir oil and the northwestern pitchout end of the uplift are the system. favorable exploration fairways. The paper by Wang et The paper by Gao and Gao illustrate how to al. demonstrate the oil migration in the Lunnan region calculate tubing behavior in high pressure and high of the Tabei Uplift. Their pyrrolic nitrogen compound temperature wells (HPHT) based on plastic incremen- distribution based technique, which has been success- tal theory in plastic mechanics. Both laboratory fully used in other basins of the world, clearly experiments and the field’s testing data have proved illustrates the migration patterns for different reservoir that the method is feasible. They conclude that its intervals in the Lunnan region. They conclude that the successful applications in three HPHT wells in China oils reservoired in the Ordovician and Carboniferous have verified its practicality. migrated laterally from west to east. In contrast, the In their paper, Zhang et al. demonstrate the effects oils reservoired in the Triassic and Jurassic first of different acidic fractions in crude oil on dynamic migrated vertically via fault conduits from the Ordo- interfacial tensions in surfactant/alkali/model oil sys- vician source kitchen and then migrated laterally from tems. They measured dynamic interfacial tensions of north to south. different acidic fractions against alkaline and/or sur- The paper by and Lee is on geochemistry of factant solutions in the laboratory. They have estab- source rocks in the Baise Basin, south China. They lished the relationships between the molecule structure present abundant new geochemical and organic pet- and interfacial tensions. rological data for this relatively unknown small basin. The paper by Cheng et al. is a simulation study of The quality of source rocks is assessed by investiga- steam-foam-drive in the super-viscous oil reservoir. tions of kerogen types and maturity of organic matter. Using their numerical simulator for the Gaosheng Oil Their research results will no doubt provide useful Field in the Bohai Bay Basin, they studied the steam- guidance for the future exploration in the basin. foam-drive under different operating conditions and Mu and Cao illustrate how to detect sandstone proposed optimal operational practice. The research reservoirs with absorption coefficients of seismic results may have some guidance for the production of Z. Jin, G. Bai, G.A. Mansoori An introduction to petroleum and natural gas exploration and production research in China J. Petrol. Sci. & Eng. 41(1-3):1–7, 2004

7 super-viscous oil from thick pay zones in other basins properties of residue fractions and KH to assess the in the world. feedstock reactivity and processability. Their findings In the paper entitled ‘‘A study on the size and have important applications in the processing of heavy conformation of linked polymer coils’’, Li et al. crude oils. investigate a linked polymer solution (LPS) with The wide spectrum of the topics dealt with in this dynamic light scattering (DLS) and scanning electron special issue reflect the wide spectrum of research microscope (SEM). They present some important activities in China. Production of this special issue findings regarding the size and the conformation of took over one year to complete. In response to a call linked polymer coils (LPC) in LPS. Furthermore, for contributions 22 manuscripts were submitted and they propose a new method to investigate the plug nineteen were chosen for publication in this special property of LPC by filtrating diluted LPS pass issue after a lengthy review process. The editors of through a micro porous filter membrane under low this special issue would like to thank the Elsevier pressure. Earth Sciences Editorial Office in the Netherlands and In their paper, Chen and Zhang demonstrate the specially Ms. Tirza van Daalen, for their cooperation impacts of fracture width and confining pressure on and encouragement in publishing this special issue. the fracture toughness. They found that the influence of fracture width on the toughness is very clear and that of the confining pressure is significant and linear. These findings provide theoretical basis as well as Affilations and addresses of the authors: reliable experimental procedures for correctly deter- mining the fracture toughness, which is required for Zhijun Jin (E-mail address: [email protected]) maximizing the effectiveness of the stimulation of low and permeability reservoirs. Guoping Bai (E-mail address: [email protected]) The last paper in this special issue is authored by Basin and Reservoir Research Center, University of Zhao et al. It is on processing of heavy crude oils. It Petroleum, Changping, Beijing 102249, PR China demonstrates that supercritical fluid extraction and fractionation (SFEF) is an important tool to prepare narrow-cuts from a variety of petroleum vacuum G.Ali Mansoori (E-mail address: [email protected]) residua. It also develops a generalized feedstock University of Illinois at Chicago, College of Engineering, , Chicago, IL characteristic index, KH. The authors conclude that (M/C 063) the narrow-cut data can be used to develop critical 60607-7052, USA