2015 Vol. 37, No. 5

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2015, 37(5): .
Abstract(580) PDF-CN(1634)
Abstract:
Research status and prospects for marine-continental shale gases in China
Guo Shaobin, Fu Juanjuan, Gao Dan, Li Heyang, Huang Jiaguo
2015, 37(5): 535-540. doi: 10.11781/sysydz201505535
Abstract(1175) PDF-CN(1807)
Abstract:
Shale gas has become one of the hot spots of unconventional natural gas exploration.At present, domestic and overseas research for shale gases is carried out mostly on marine formations;however, research for marine-continental shale gases is still at the initial stage.In China, marine-continental shales rich in organic matter are mainly distributed in the Benxi, Taiyuan and Shanxi formations of Carboniferous and Permian age in the Ordos, Qinshui and southern North China basins in the north, and the Longtan Formation of Permian age in the southwestern Sichuan Basin, the western Guizhou province, and the central Hunan and southern Hunan depressions in the south.This paper summarizes present research results for marine-continental shale gases in China, and shows that the kerogen types of marine-continental shales are mainly II and III.Except for the south and east of the southern North China Basin, organic matter maturity is generally high, commonly greater than 1.5 %Ro and is in the high mature and over-mature stages.The lithofacies of marine-continental shales change rapidly and the thickness of a single layer is typically thin, often interbedded with coals, tight sandstones, and even limestones.As a result, separately developing shale gases from such thin layers will face a great challenge in development costs and technology.The joint development of shale gases, tight gases and coal bed gases from multiple target layers will be an effective new strategy.
Structural characteristics of micro-pores and factors controlling low-permeability reservoirs in the Huangliu Formation in the Dongfang area, Yinggehai Basin
Xie Yuhong, Zhang Ya, Zhang Shaonan, Zhang Yingzhao, Liu Jinghuan
2015, 37(5): 541-547. doi: 10.11781/sysydz201505541
Abstract(949) PDF-CN(1410)
Abstract:
Characteristics of micro-pore structures and factors controlling the low-permeability reservoirs in the Huangliu Formation in the Dongfang area of the Yinggehai Basin were studied by mercury injection experiments with constant rates.The average pore radius of the reservoirs is about 100-140 μm, the average throat radius is about 1-5 μm, and the mainstream throat radius is less than 5 μm.The permeability is not correlated with pore radius, and reservoirs with different permeabilities can have similar pore radius distributions.In contrast, permeability is strongly associated with throat radius and its distribution.The throat radius and the mainstream throat radius decrease as permeability becomes lower, and the distribution range gets narrower.The throat to pore ratio increases as permeability decreases, and its distribution range becomes wider.The low permeability of rocks in the study area can be explained by their small throat radius.Strong compaction effects and authigenic clay minerals are the main factors which undermine the micro-pore structures and make the permeability low.
Reservoir formation and modification controlled by thermal events in the Xihu Sag, East China Sea Basin
Gao Weizhong, Yang Caihong, Zhao Hong
2015, 37(5): 548-554. doi: 10.11781/sysydz201505548
Abstract(875) PDF-CN(1527)
Abstract:
There have been many hydrocarbon explorations in the Xihu Sag of the East China Sea Basin recently, and these have shown that reservoir dissolution controlled by thermal events have impacted hydrocarbon accumulations in those formations over 3 000 m deep.We aimed to clarify these thermal events, and their control on reservoir dissolution, by using magnetic field, thermal field and 3D seismic datasets, and in particular to investigate the characteristics of ancient volcanos in the study area.Our study used core samples, thin sections, field emission spectroscopy environmental scanning electron microscopy (SEM) and physical properties.Thermal fluids carrying acids accelerated source rock evolution which released further organic acids.These acids led to the generation of secondary pores which modified the original sandstone reservoirs.In view of reservoir developments in different areas, we discuss the mechanism of reservoir reconstruction by thermal events, and predict the likely distribution of reservoirs influenced by thermal events.
Different characteristics of strike-slip faults and the formation of large and medium-scaled oil and gas fields in the Liaodong Bay Depression
Liu Yongjun, Xu Changgui, Wu Kui, Zhang Rucai, Zhu Wensen, Li Minggang
2015, 37(5): 555-560. doi: 10.11781/sysydz201505555
Abstract(1037) PDF-CN(1507)
Abstract:
Strike-slip fault activities are common in the Liaodong Bay Depression.There are five major strike-slip fault zones, including the western strike-slip fault, Liaoxi extensional strike-slip fault, Liaozhong1 fault, Liaozhong2 fault and Liaodong1 fault.The characteristics of these faults are obviously different, generally strong in the east and weak in the west.As a result, the faults are divided into two fault zones: a "single and strong strike-slip fault zone" in the east and a "duplex and weak strike-slip fault zone" in the west.The eastern strike-slip activities are strong and the strike-slip features are obvious.The western strike-slip activities are weak and only a part of them shows strike-slip characteristics.The differences among strike-slip faults result in the formation of different strike-slip structures.These also control the formation of different types of traps as well as the migration and preservation of oil and gas, which ultimately determines the formation and distribution of large and medium-scaled oil and gas fields.
Characteristics and main factors controlling the Jurassic gas reservoirs in the middle section of the Western Sichuan Depression
Chen Yingbin, Wang Yanqing, Hu Ye
2015, 37(5): 561-565. doi: 10.11781/sysydz201505561
Abstract(1278) PDF-CN(1401)
Abstract:
In the middle section of the Western Sichuan Depression, lithologic and tectonic-lithologic gas reservoirs are widespread in the Jurassic.These reservoirs feature multiple layers, local enrichment, no obvious gas/water boundary, low temperature and overpressure.Accumulation conditions in the Jurassic indicate that gases were mainly sourced from the Lower Jurassic and preserved in the Upper Jurassic.The fourth and fifth members of the Xujiahe Formation provided important source rocks for natural gases.Vertical pathways connections between source rocks and reservoirs were the factors controlling natural gas accumulations.The physical properties of the Jurassic sandstones varied both horizontally and vertically.The development of favorable reservoirs also influenced the enrichment of natural gases.A large amount of vertical fractures which extended directly to the earth surface were found in the front of the Longmen Mountain and on both sides of the Longquan Mountain.They destroyed the neighboring cap formations, and damaged the sealing capacity of the Jurassic sand bodies in the adjacent slope area.Effective traps were necessary for natural gas enrichment in Jurassic.
Pore characteristics and their evolution in Paleogene mud shales, Dongying Sag, Bohai Bay Basin
Li Juyuan
2015, 37(5): 566-574. doi: 10.11781/sysydz201505566
Abstract(1055) PDF-CN(1574)
Abstract:
The pore characteristics of mud shales from the lower part of the third member and the upper part of the fourth member of the Paleogene Shahejie Formation in the Dongying Sag were studied through modern experimental methods.The relationships between pore size distribution, porosity and burial depth were analyzed.Five major pore types of the Paleogene mud shales in the study area were identified, including intercrystalline pores in clay minerals, intercrystalline pores in calcites, intergranular pores in sands, intercrystalline pores in pyrites, and organic pores.Nano pores were well developed in the mud shales, and the pores smaller than 25 nm accounted for 49.7% to 86.3% of total pores.The changing modes of porosity with depth are discussed.An model of how the pores in the mud shales evolved in the Paleogene in the Donging Sag was established from their characteristics and knowledge of their controlling factors.There were three evolution stages for pores in the Paleogene mud shales, including the original formation stage, the transformation stage and the hysteresis stage, among which the second and the third contributed more to the hydrocarbon storage capacity of the shales.Greater thickness, high organic abundance, rich pyrite and active thermal sulfate reduction effect were favorable conditions for reservoir development in mud shales.
Depositional system and sand body distribution in the third member of the Yanchang Formation in the Yijun area in the southern Ordos Basin
Wu Jiyuan, Feng Lin, Liu Shuping, Liu Xiaochen, Chen Lin, Peng Li
2015, 37(5): 575-581. doi: 10.11781/sysydz201505575
Abstract:
The southern Ordos Basin is an important oil-producing area in China and the third member of the Upper Triassic Yanchang Formation in the Yijun area in the southern Ordos Basin is a major hydrocarbon exploration target.Based on well logs and 3D seismic data, the provenance of the study area was studied using cathode luminescence, seismic progradation tendency and angle conversion methods.The Yijun area was influenced by the Weibei uplift in the south during the Late Triassic.The deposition system in the study area developed when the third member of the Yanchang Formation was deposited, and this provenance controlled the distribution of sand bodies.Braided river delta-front sediments were widespread in the study area, and subsea river channels and mouth bar sand bodies were favorable reservoirs for hydrocarbons.The distribution of sand bodies and features of the sedimentary facies from the third section to the first section of the third member of the Yanchang Formation were studied to determine its potential for hydrocarbon reservoirs.
Characteristics and solution intensity of karst formations in Ordovician carbonates in the Halahatang area of the northern Tarim Basin
Dan Yong, Liang Bin, Cao Jianwen, Zhang Qingyu, Hao Yanzhen, Li Jingrui
2015, 37(5): 582-590. doi: 10.11781/sysydz201505582
Abstract:
Fractured and vuggy reservoirs were found in several Ordovician carbonate formations in the Halahatang area of the northern Tarim Basin.The lithology of different formations and their vertical distribution were studied based on microscopic observations and geochemical testing of core samples.Dissolution tests of different types of carbonates showed that the contents of argillaceous matter and MgO could influence carbonate solubility.The intensity of dissolution decreased from pure limestones, dolomitic limestones, dolomites to muddy limestones.The Ordovician carbonates were classified into two classes, three types and five subtypes.The Yijianfang Formation and the first and second members of the Yingshan Formation are continuous limestones with strong karstification.The first member of the Lianglitage Formation and the third and fourth members of the Yingshan Formation are dolomitic limestones with medium karstification.The other formations were weakly karstified.Drilling results and the presence of "stringed beads" on seismic profiles indicated that the types of karst formation controlled the development of fractured and vuggy reservoirs.
Distribution and significance of the Ordovician Qrebake and Yijianfang formations in the Central Uplift of the Tarim Basin
Cai Xiyao, Ma Yuchi, Chen Yue, Qian Yixiong, You Donghua
2015, 37(5): 591-598. doi: 10.11781/sysydz201505591
Abstract(976) PDF-CN(1001)
Abstract:
The Qrebake Formation of the Upper Ordovician and the Yijianfang Formation of the Middle Ordovician have been intersected in ten wells in the Central Uplift of the Tarim Basin.They belong to two stratigraphic sequences: the Lianglitage/Qrebake/Yijianfang/Yingshan formations, and the Queerqueke/Qrebake/Yijianfang/Yingshan formations.The Qrebake Formation is composed of purplish red, brown and grey micritic limestones, marls and calcareous mudstones representative of slope facies.This formation is about 17-25 m thick, and has a Pygodus anserinus zone at the bottom.The Yijianfang Formation is composed of grey micritic sand-clastic limestones, grained limestones and bioclastic limestones representive of open platform and platform margin facies.This formation is about 80-120 m thick, and has a Pygodus serrus fossil zone at the top.The Qrebake and Yijianfang formations are mainly distributed in the lower parts of the uplift edge and the transition area from the uplift to the depression, while a sedimentary gap for the two formations is observed in the Central Uplift.The Ordovician of the Central Uplift is divided into the uplift zone, the transition zone (A, B), and the depression zone.The western boundary of the transition zone should be at least 100 km to the west compared to previous studies.During the Middle and Late Ordovician, the study area was an open platform to platform margin and slope facies, and developed no hydrocarbon source rocks of the "Salgan" type.Two sets of favorable reservoir and cap assemblages have been discovered in the transition zone, showing a good potential for hydrocarbon exploration.
Separation of fractures and cavities in carbonate reservoirs in the Tahe Oil Field
Rong Yuanshuai, Hu Wenge, Pu Wangfen, Wu Bo, Liu Yao, Lu Xinbian, Li Xinhua
2015, 37(5): 599-605. doi: 10.11781/sysydz201505599
Abstract(1055) PDF-CN(1035)
Abstract:
Most of the fractures and cavities that remain in carbonate reservoirs are water flooded in the Tahe Oil Field.This complex distribution of oil and water makes successful exploration and production more difficult.A new concept and some methods for separating fractures and cavities in carbonate reservoirs are proposed based on petroleum geology cocepts.Separation models were classified into three types and seven sub-types as follows: separation by river channels or pipes (separation by branch channels, fillings, or U pipes), separation by faults (separation by internal faults, intersecting faults or parallel faults), and separation by karst channels.This method was applied to some old oil fields, and was proved effective in deploying a denser coverage of new wells.The traditional well spacing limit of at least 500 m was broken.The potential of fracture and cavity reservoirs is proposed, and the risk of water flooding in the dense deployment of new wells was reduced.
Characteristics of shale gas reservoirs and evaluation of their gas potential in Sujiatun area, Lishu Fault Depression, Songliao Basin
Song Zhenxiang, Li Zhongbo, Zhang Xi, Zhou Zhuoming, Yang Hao
2015, 37(5): 606-613. doi: 10.11781/sysydz201505606
Abstract(1151) PDF-CN(963)
Abstract:
In addition to the characteristics of source rocks, we should pay more attention to the evaluation of reservoir characteristics in shale oil and shale gas resource assessment, especially evaluation of fracturing and gas content which are directly involved in the mobility of resources.In this paper, we studied the hydrocarbon generation potential of mud shale as well as the fracturing properties and gas content on the basis of test results from the first member of Yingcheng Formation in well Su2 in the Sujiatun area of the Lishu Fault Depression.The results show that the mud shale from the first member of Yingcheng Formation have good shale gas generating conditions in this area.High content of brittle minerals, high Young's modulus and low Poisson's ratio make the mud shale easy to crack.The porosity and permeability of the mud shale are generally low, but there are a lot of natural fractures and micro-fractures;as well single vertical cracks are prone to form during the fracturing process.Beyond that, there are a lot of micro-nanometer pores under the electron microscope, mainly micropores and mesopores.All of these different scales of fractures and the availability of pores provide a favorable migration pathway and storage space for shale gas.During drilling, measurements and logging in the first member of Yingcheng Formation, many wells have shown a large amount of oil and gas;meanwhile, high-yield gas flows were obtained in wells Su2 and Li2.Field desorption tests showed that the averaged shale gas content in the first member of Yingcheng Formation in well Su2 is 2.5 m3/t, representing a considerable resource and a good exploration and development prospect.
Impact of salt on hydrocarbon accumulation in South Atlantic passive margin basins
Tao Chongzhi, Yin Jinyin, Lu Hongmei, Wang Yifan, Liu Junlan, Niu Xinjie
2015, 37(5): 614-618. doi: 10.11781/sysydz201505614
Abstract:
South Atlantic passive margin basins experienced a similar tectonic evolution and regionally distributed salt was deposited during the Aptian.Based on a comprehensive study of regional tectonics, depositional environment and hydrocarbon accumulation, integrated with the study of salt-related structural styles determined by analyzing regional seismic sections, three tectonic belts, which include extensional domain, transitional domain and compressional domain, were recognized in the 6 main salt basins.The pre-salt source rocks in the Brazil salt basins are still in the oil window.In West Africa, the post-salt source rocks experienced a higher maturation rate than the pre-salt source rocks.The salt has a relatively higher thermal conductivity and can restrain the hydrocarbon generation of the pre-salt source rocks but accelerate that of the post-salt source rocks.The salt flow resulted in several kinds of salt-related structural traps for hydrocarbon accumulation in the post-salt sequences.Reserves in the post-salt related structural traps account for 84.8% of the total post-salt reserves.The salt windows developed in the extensional domain served as hydrocarbon migration pathways and controlled hydrocarbon accumulations in the post-salt sequence.The thick salt provided a regional cap rock, which controlled the pre-salt hydrocarbon accumulations in the transitional-compressional domain.
Relationship between resource-rich regions and sweet spots for tight oils: A case study of the Williston Basin in the USA
Zhang Xinshun, Wang Hongjun, Ma Feng, Sun Xiangcan, Song Zhihui
2015, 37(5): 619-626. doi: 10.11781/sysydz201505619
Abstract(1143) PDF-CN(1133)
Abstract:
Tight oils from the Bakken Formation in the Williston Basin in the USA were studied to find out the relationship between the resource-rich regions and sweet spots for tight oils.Some maps with multiple parameters were drawn based on drilling and logging data from 948 wells.Genetic method, volume method and decline curves were used to evaluate the abundance of tight oils in the study area.The distribution of sweet spots was studied by comparing differences in abundance combined with geological data.The results show that high-quality hydrocarbon source rocks of the Bakken Formation were a prerequisite for the generation of tight oils.The resource-rich regions predicted by the genetic and volume methods clearly varied with the occurrences of tight oils, and could not be used individually in the prediction of sweet spots.The transitional region adjacent to the resource-rich regions had some favorable conditions for tight gas development, such as closeness to the hydrocarbon generation center, formation overpressure, high gas-oil ratio and tectonic setting.These transitional regions often developed in the slope zone of the basin or on positive structures such as anticlines.
Geochemical characteristicsof natural gases and crude oils in the Xihu Sag of East china Sea Basin
Cao Qian, Xu Xuhui, Zeng Guangdong, Zhou Xiaojin, Jiang Ping, Wang Ling
2015, 37(5): 627-632. doi: 10.11781/sysydz201505627
Abstract(1260) PDF-CN(890)
Abstract:
Studies of the composition, light hydrocarbons and carbon isotopes of natural gases from the Xihu Sag showed that the gases were a mix of coal-type (accounting for the major proportion) and oil-type gases havinghigh maturities.They were mainly derived from type II source rocks in the PinghuFormation and underlying formations during the mature and over-mature stages.Crude oils from the Xihu Sag were classified into light oils and condensates according to studies of their physical properties, saturated hydrocarbons, carbon isotopes and light hydrocarbons.These two types of crude oil showed similar physical properties suggestive of acoal origin, and were generated in fresh water lakeswith weakly anoxic conditions.Some of the crude oils were mature (Ro<1.0%)and some are high-to over mature (Ro=1.3%~2.0%).
Genetic types and sources of natural gases reservoired in the second member of the Xujiahe Formation in the Xinchang area of the Western Sichuan Depression
Bai Fan, Wu Xiaoqi, Zeng Huasheng, Yuan Xiaoyu
2015, 37(5): 633-640. doi: 10.11781/sysydz201505633
Abstract(892) PDF-CN(1001)
Abstract:
The second member of the Upper Triassic Xujiahe Formation is an important exploration target for terrestrial natural gases in the Sichuan Basin.The geochemical characteristics of natural gases indicated that the gases reservoired in the second member of the Xujiahe Formation in the study area have high dryness coefficients generally over 0.95.The δ13C1, δ13C2 and δD1 values are in the ranges of -34.5‰~-30.3‰, -29.1‰~-23.4‰ and -168‰~-157‰, respectively.The alkane gases mainly display positive stable carbon and hydrogen isotope values with several samples being partially reversed between ethane and propane carbon isotopes.These gases are of mixed origin, and the heavy hydrocarbon gases were mainly derived from the secondary cracking of oil augmented with coal-type gas, whereas methane was mainly a coal-type gas.Gas-source correlations indicated that the natural gases reservoired in the second member of the Xujiahe Formation were derived mainly from the source rocks in the Ma'antang and Xiaotangzi formations and augmented by those in the second member of the Xujiahe Formation itself.
Characteristics of high-quality hydrocarbon source rocks and their contributions to reservoirs in the Erlian Basin
Wang Jian, Wang Quan, Zhong Xuemei, Dong Xiongying, Ma Xuefeng, Sui Limin
2015, 37(5): 641-647. doi: 10.11781/sysydz201505641
Abstract:
The Erlian Basin consists of many sags characterized by multiple provenances, changeable phases and a low degree of thermal evolution.The identification of high-quality source rocks determines the direction of exploration efforts.By building correlations between TOC and HI, and analyzing the changes of organic carbon contents under various sedimentary circumstances, we have shown that stable sedimentary areas such as shallow lakes and relatively deep lakes commonly develop high-quality source rocks, and unstable sedimentary areas like rivers and shallow shore lakes commonly develop poor- or medium-quality source rocks.We can use TOC to classify source rock levels.The source rocks from stable sedimentary areas are divided into high (TOC > 2%), medium (1% < TOC < 2%) and poor (TOC < 1%) quality source rocks.The source rocks from the unstable sedimentary areas are divided into medium (1% < TOC < 2%) and poor (TOC < 1%) quality source rocks.Furthermore, based on TOC values calculated from well logging data, the thickness and distribution of different levels of source rocks can be ascertained.High-quality source rocks have a close relationship with oil and gas reservoirs, and are the main sources of oil to these reservoirs.The source contribution from high quality source rocks is > 70% even though they constitute only 20% of total source rock volume.Consequently, the distribution zones of high-quality source rocks are commonly favorable areas for large scale reserves.
Effect of liquid hydrocarbons on gas adsorption in alacustrine shale: A case study of the Yanchang Formation, Ordos Basin
Liu Guoheng, Huang Zhilong, Jiang Zhenxue, Chen Jianfa, Chen Feiran, Xing Jinyan
2015, 37(5): 648-653. doi: 10.11781/sysydz201505648
Abstract(1105) PDF-CN(1222)
Abstract:
The effect of liquid hydrocarbons on the gas adsorption capacity of lacustrine shales from the Yanchang Formation in the Ordos Basin has been studied using a series of integrated experimental methods including X-ray diffraction of bulk and clay minerals, Soxhlet extraction, focused ion beam scanning electron microscopy(FIB-SEM), low-temperature N2 adsorption and high-pressure CH4 adsorption methods.The results show that the lacustrine shale from the Yanchang Formation is in the middle diagenetic stage A.The thermal maturity is relatively low, and contributes to the absence of organic matter pores.However, it is sufficiently high enough forthe production of liquid hydrocarbons which can block up pores with a diameter of 4 nm.Methane can dissolve in these liquid hydrocarbon, whereas nitrogen cannot.As a result, the specific area and adsorbed capacity acquired in low-temperature N2 adsorption analysis show great differences between samples before and after extraction.However, the difference does not exist in the CH4 adsorption analysis.This means that a certain proportion of CH4 exists in these samples in a dissolved form.It is necessary to pay attention to free hydrocarbons during studies of gas adsorption capacity of shales with low thermal maturity usinghigh pressure CH4 adsorption methods.
2D NMR distribution function for microscale remaining oil
Wang Jun, Meng Xiaohai, Wang Weimin, Liu Naigui
2015, 37(5): 654-659. doi: 10.11781/sysydz201505654
Abstract(1084) PDF-CN(1011)
Abstract:
The effective distinction between oil and water in porousmedia is a difficult problem to solve in research on microscale remaining oil.Since a NMR relaxation time spectrum can accurately measure fluid saturation in porous media, we can apply it to this research by introducing a new parameter: diffusion coefficient, which can solve the problem of the quantitative distinction between oil and water.At the same time, the problem of the missing components in high viscous oil measurement has been completely solved through improving equipment, optimizing the calculation method and establishing the stimulated echo bipolar pulse gradient.As a result, the technology can fully meet the demand of microscale remaining oil research, which provides a new experimental technique for the quantitative characterization of this remaining oil.
Application of characteristic gas adsorption curves for shales
Bao Yunjie, Zhou Yongbing
2015, 37(5): 660-664. doi: 10.11781/sysydz201505660
Abstract(885) PDF-CN(1297)
Abstract:
The study of the gas adsorption capacity of shales is a basic tenet of shale gas research.The Langmuir's volume is an important parameter when evaluating the gas adsorption capacity of shales.The adsorption potential theory was applied here to study the gas adsorption capacity and characteristics of the adsorption systems in shales for different gases.Experiments showed that different adsorption curves were obtained for the adsorption systems of shales and different gases.These curves were not influenced by temperature and so could be used in the prediction of isothermal adsorption curves.Some shale samples were collected from the Wufeng and Longmaxi formations in the southeastern Sichuan Basin, and were tested to predict their adsorption capacity under formation conditions.It was found that the adsorption amount was obviously different from the Langmuir's volume, which demonstrated the controlling effects of temperature and pressure on the adsorption capacity of shales.
Classification and evaluation of coalbed methane resources/reserves based on the Petroleum Resources Management System (PRMS) rules
Fa Guifang, Yi Yanjing, Liu Yazhao, Yuan Ruie, Wang Zhongsheng
2015, 37(5): 665-670. doi: 10.11781/sysydz201505665
Abstract(1396) PDF-CN(1413)
Abstract:
This paper introduces a set of definitions and classification requirements for coalbed methane (CBM) resources/reserves based on the Petroleum Resources Management System (PRMS).General requirements for the classification of CBM reserves are outlined from seven perspectives: ownership considerations, governmental regulatory and project approval considerations, drilling requirements, testing requirements, infrastructure and market considerations, timing of production and development, and economic requirements.Combined with the geological and engineering conditions, current economics, operating conditions and government policies of CBM, the principles used to classify Proved, Probable, and Possible (3P) reserves and contingent resources were formulated, and demonstrated by a case analysis.These data provide important reference points for the reasonable assessment of CBM reserves.
Han Yu
2015, 37(5): 671-671.
Abstract:
Xu Wenming
2015, 37(5): 672-672.
Abstract(497) PDF-CN(1045)
Abstract: