Development of petroleum geology in China: Discussion on continuous petroleum accumulation

Abstract

Petroleum exploration targets are extending gradually from the single conventional trap reservoirs to the large-scale unconventional continuous accumulations. Oil and gas reservoirs have been divided into two types based on the trapping mechanism and distribution of oil and gas: conventional single-trap reservoirs, such as the Daqing oil field in Songliao Basin and the Kela-2 gas field in Tarim Basin; and unconventional continuous petroleum accumulation, such as Upper Paleozoic tight gas and Mesozoic tight oil in Ordos Basin, and Upper Triassic tight gas in Sichuan Basin. Two typical geologic characteristics of continuous petroleum accumulation involve: (1) coexisting source and reservoir, petroleum pervasive throughout a large area tight reservoirs, and no obvious traps or well-defined water-oil and gas contracts; (2) non-buoyancy accumulation, continuous petroleum charge, and no significant influence by buoyancy. Continuous petroleum accumulation generally have nm-scale pore throats, and the diameters range of 10-500 nm. The geometry and connectivity of these pore throats has significant impact on the migration and distribution of oil and gas in continuous petroleum accumulation. China has numerous continuous petroleum accumulation containing various petroleum deposits, and the exploration of continuous resources is very promising. Unconventional petroleum geology will become an important new subject in petroleum geology in future, and the nano-technology will function greatly on research, exploration and development of the hydrocarbon accumulation in nanopore-throats.

Keywords

continuous petroleum accumulation / unconventional petroleum geology / nano-pore-throat / tight gas / tight oil

References

[1] Brown A. Evaluation of Possible Gas Microseepage Mechanisms. AAPG Bulletin, 2000, 84(11): 1775-1789.

[2] Dai J X, Zou C N, Tao S Z, . Formation Conditions and Main Controlling Factors of Large Gas Fields in China. Natural Gas Geoscience, 2007, 18: 473-484.

[3] Huang S J, Huang K K, Li Z M, . TSR-Derived Authigenic Calcites in Triassic Dolomite, NE Sichuan Basin, China—A Case Study of Well HB-1 and Well L-2. Journal of Earth Science, 2012, 23(1): 88-96.

[4] Law B E. Basin—Centered Gas Systems. AAPG Bulletin, 2002, 86(11): 1891-1919.

[5] Nelson P H. Pore Throat Sizes in Sandstones, Tight Gas Sands, and Shales. AAPG Bulletin, 2009, 93(3): 329-340.

[6] Schmoker J W, Klett T R. U.S. Geological Survey Assessment Concepts for Continuous Petroleum Accumulations: U.S. Geological Survey Digital Data Series DDS-69-D, 2005 Denver: USGS, 1-10.

[7] Schmoker J W. Gautier D L, Dolton G L, Takahashi K I. Method for Assessing Continuous-Type (Unconventional) Hydrocarbon Accumulations. National Assessment of United States Oil and Gas Resources— Results, Methodology, and Supporting Data: U.S. Geological Survey Digital Data Series DDS-30, 1CDROM, 1995 Denver: USGS, 1-3.

[8] Tan X C, Xia Q S, Chen J S, . Basin-Scale Sand Deposition in the Upper Triassic Xujiahe Formation of the Sichuan Basin, Southwest China: Sedimentary Framework and Conceptual Model. Journal of Earth Science, 2013, 24(1): 89-103.

[9] Wilson W B. Wrather W E, Lahee F H. Proposed Classification of Oil and Gas Reservoirs. Problems of Petroleum Geology, 1934 Tulsa: AAPG Memoir, 433-445.

[10] Zhang H F, Zhang W X. Petroleum Geology, 1999, the Third Edition Beijing: Petroleum Industry Press

[11] Zou C N. Unconventional Petroleum Geology, 2011 Beijing: Geological Publishing House, 1-310.

[12] Zou C N, Zhang G Y, Tao S Z, . Geological Features, Major Discoveries and Unconventional Petroleum Geology in the Global Petroleum Exploration. Petroleum Exploration and Development, 2010, 37(2): 129-145.

[13] Zou C N, Dong D Z, Wang S J, . Geological Characteristics, Formation Mechanism and Resource Potential of Shale Gas in China. Petroleum Exploration and Development, 2010, 37(6): 641-653.

[14] Zou C N, Tao S Z, Zhu R K, . Formation and Distribution of “Continuous” Gas Reservoirs and Their Giant Gas Province: A Case from the Upper Triassic Xujiahe Formation Giant Gas Province, Sichuan Basin. Petroleum Exploration and Development, 2009, 36(3): 307-319.

[15] Zou C N, Tao S Z, Yuan X J, . Global Importance of “Continuous” Petroleum Reservoirs: Accumulation, Distribution and Evaluation. Petroleum Exploration and Development, 2009, 36(6): 669-682.

[16] Zou C N, Tao S Z, Yuan X J, . The Formation Conditions and Distribution Characteristics of Continuous Petroleum Accumulations. Acta Petrolei Sinica, 2009, 30(3): 324-331.

[17] Zou C N, Yang Z, Tao S Z, . Nano-Hydrocarbon and the Accumulation in Coexisting Source and Reservoir. Petroleum Exploration and Development, 2012, 39(1): 13-26.

[18] Zou C N, Zhu R K, Wu S T, . Types, Characteristics, Genesis and Prospects of Conventional and Unconventional Petroleum Accumulations—Taking Tight Oil and Tight Gas in China for an Instance. Acta Petrolei Sinica, 2012, 33(2): 173-187.

[19] Zou C N, Zhu R K, Bai B, . First Discovery of Nano-Pore Throat in Oil and Gas Reservoir in China and Its Scientific Value. Acta Petrologica Sinica, 2011, 27(6): 1857-1864.

[20] Zou C N, Yang Z, Cui J W, . Formation Mechanism, Geological Characteristics and Development Strategy of Nonmarine Shale Oil in China. Petroleum Exploration and Development, 2013, 40(1): 15-27.

[21] Zou C N, Zhang G S, Yang Z, . Geological Concepts, Characteristics, Resource Potential and Key Techniques of Unconventional Hydrocarbon: On Unconventional Petroleum Geology. Petroleum Exploration and Development, 2013, 40(4): 385-399.