Search

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The pre-Jurassic in the north depression of the Tuha depression is the most favorable replacement strata to obtain new reserves in the Turpan–Hami Basin. (Pre-Jurassic, in this paper, refers to the Permian and Triassic.) The main source rocks are the Taodonggou Group, of which the burial history and hydrocarbon generation potential remain unconfirmed. The investigation of the burial and thermal history is vital for the basin analysis and hydrocarbon exploration. Therefore, in this paper, by using the acoustic time difference method, vitrinite reflectance method, stratigraphic trend method and PetroMod-1D software, the differential characteristics of denudation thickness, burial history and thermal evolution history of different tectonic units in different periods of Taibei Sag in the Turpan–Hami basin are studied, and their influence on the petroleum system is analyzed, and then the zones with exploration potential are optimized. The results show that the Taibei Sag has experienced multiple tectonic uplift events. The Late Indosinian movement has profound effects on the Taodonggou Group source rocks. The rather large uplift amplitude postpones the maturation of source rocks. In addition, the Turpan–Hami Basin is a typical cold basin. Therefore, the thermal maturity of the source rocks is relatively low, with respect to the relatively deep burial. The thermal histories of the different sub-sags in the study area are slightly differentiated from each other. The Taodonggou Group source rocks in the Taibei Sag generally became mature during the Mid–Late Jurassic epoch, except for those in the Central–Southern Shanbei sub-sag, represented by Well LT-1, which reached the mature stage during the Late Triassic epoch. The study area has well-developed reservoir rocks, and effective reservoir bodies are formed in the slope zone and near the Tainan Sag, due to the higher porosity and permeability of reservoir rocks. The statistics related to the faults and an analysis of the structural styles of oil reservoirs indicate that the structural slope and anticline of the Huobei, Lianbei and Shanbei sub-sags are favorable for increasing reserves and production of hydrocarbons. [ABSTRACT FROM AUTHOR]

Copyright of Coal Geology & Exploration is the property of Xian Research Institute of China Coal Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Marine shale gas, represented by the shale gas from Wufeng-Longmaxi formations in southern China, is the main field for shale gas exploration and development in China. In recent years, marine shale gas exploration and development have been constantly facing new problems and challenges. Expanding new fields of shale gas resources and increasing shale gas production are still top priorities. The distribution characteristics, resource potential, and favorable area prediction of shale gas in typical marine formations in China are sorted out, with the results as follows. The geological and recoverable resources of shale gas in Wufeng-Longmaxi formations in Sichuan Basin and its peripheral regions are (17.50-33.19)×1012 m3 and (3.50-6.14)×1012 m3, respectively, with deep shale gas resources accounting for over 50%, mainly distributed in the high and steep structural belt in eastern Sichuan and in the low steep structural belt in southern Sichuan. The geological and recoverable resources of shale gas in the Permian Wujiaping Formation are (8.7-24.6)×1012 m3 and (1.3-3.7)×1012 m3, respectively, with exploration potential in areas such as Kaijiang-Liangping, Longjuba, Jiannan, and Sanxing in eastern Sichuan. The geological and recoverable resources of shale gas in the Qiongzhusi Formation are (5.69-12.71)×1012 m3 and (0.89-1.06) ×1012 m3, respectively, with favorable areas mainly distributed in areas such as Jingyan-Jianwei-Weiyuan-Ziyang in southwestern Sichuan, Nanjiang in northern Sichuan, and Yichang in the middle Yangtze region. The ancient marine formations such as the Doushantuo Formation, Hongshuizhuang Formation, and Xiamaling Formation have certain potential of shale gas resources, which are potential continuation of shale gas resources. The favorable areas for shale gas in the Doushantuo Formation are mainly distributed in western Hunan and Hubei and southeast Chongqing, while the favorable areas for shale gas in the Hongshuizhuang Formation are mainly distributed in the Chengde-Kuancheng area of Hebei. The favorable areas for shale gas in the Xiamaling Formation are mainly distributed in the areas of Zhuozhou in Hebei, Fangshan, Mentougou, Changping in Beijing, and Lanqi-yingzi. Based on this, three suggestions are further proposed for the future exploration direction of marine shale gas: the first is to focus on deep to ultra-deep and normal pressure shale gas, move towards new layers, and expand the field of shale gas exploration; the second is to deepen and enrich the exploration theory of deep to ultra-deep shale gas, normal pressure shale gas, and shale gas of new layer in the new area; the third is to focus on the improvement and innovation of deep to ultra-deep shale gas drilling and production technology and supporting equipment, and reduce the drilling and production costs of single wells of normal pressure shale gas.

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, Chang 6 member in Huangling area of Ordos Basin was taking as an example, to clarify the characteristics of tight sandstone reservoirs. The reservoir physical properties was analyzed, and the main controlling factors of the area was evaluated by means of cast thin section, scanning electron microscope, and high-pressure mercury injection. Finally, the evaluation of Chang 61, Chang 62, Chang 63 and Chang 64 reservoirs is completed. The results showed that the rock types are mainly feldspar sandstone and lithic feldspar sandstone, and the rock debris is mainly composed of metamorphic rock debris and sedimentary rock debris, with less volcanic rock debris. The maturity of rock particles is low, and the roundness is dominated by corrugating angle. The porosity, and permeability of Chang 6 reservoir in the area is about 0.6% ~ 17% and 0.01mD~3.29mD, respectively. The pore types are mainly residual intergranular pores, dissolved intergranular pores and dissolved intragranular pores. There are four microfacies: turbidite waterway, tongue, between tongues and between turbidite waterways. The reservoir physical properties of turbidite waterway and tongue are better than those between tongues and turbidite waterways. Diagenesis includes compaction, dissolution, cementation and metasomatism. Compaction is mainly mechanical compaction, and mica directional arrangement can be seen. Cementation includes carbonate cementation, clay mineral cementation and siliceous cementation. The study area is mainly dominated by type II reservoirs, and type I and type III reservoirs are distributed in point. [ABSTRACT FROM AUTHOR]

Productive breakthroughs have been achieved for the exploration and development of marine shale gas in the Sichuan Basin, and 6 shale gas fields have been built including Fuling, Weiyuan, Changning, Zhaotong, Weirong and Yongchuan. Continental shale gas is an important exploration replacement layer series with great potential. By the approaches of whole rock X-ray diffraction, TOC content, carbon isotope of kerogen, organic petrology, combined determination of high-pressure mercury injection and nitrogen adsorption, argon ion polishing and scanning electron microscope, and physical property test, the formation conditions of shale gas in the Jurassic Daanzhai Member of the Sichuan Basin were discussed, and the main controlling factors of shale gas enrichment were proposed. Results show that continental shale in the Jurassic Daanzhai Member in the Sichuan Basin is featured by rapid lithofacies changes, strong heterogeneity, frequent interbedding of shale, sandstones and limestones, low organic matter abundance, TOC ranging from 0.04% to 3.89% with type Ⅱ2 and Ⅲ of organic matters, low degree of thermal evolution with Ro values ranging from 1.10% to 1.83%, producing both condensate oil and wet gas. Continental shale has high porosity, ranging from 0.95% to 8.42%, There are mainly inorganic mineral pores dominated by micropores and mesopores. The average gas content of field test is 0.96 m3/t. It is clear that semi-deep lacustrine facies, favorable lithofacies assemblage, fractures and preservation conditions are the main controlling factors of continental shale gas enrichment. Based on the analysis of main controlling factors, highlighting the quality and thermal evolution degree of continental shale, combined with preservation conditions and engineering technical conditions, an evaluation criterion of favorable areas for continental shale gas in the Daanzhai Member in the Sichuan Basin was established. Combined with GIS integrated spatial superposition technology, several favorable zones were proposed, including the southwest of Yuanba, the southeast of Langzhong, Yilong, the northwest of Fuling and the northwest of Jiannan areas.

An understanding of the tectonic stress field distribution in the carbonate reservoirs of the Tahe Oilfield is essential for oil and gas migration and reservoir reconstruction. This study adopts a geological genesis perspective and integrates the unique attributes of the carbonate reservoirs in the Tahe Oilfield to simulate three-dimensional stress fields using the finite element method and Petrel software. The simulation, which takes pore pressure and boundary constraints into consideration, aligns with the findings of acoustic emission tests conducted by previous researchers and validates the model by corroborating the maximum horizontal principal stress direction with imaging logging interpretations. With subsequent utilization of the generalized Coulomb-Mohr shear failure criterion and the Griffith generalized maximum tensile stress criterion, the simulated stress enables the prediction of the total fracture intensity. To complement this analysis, we integrate seismic data and fault formation mechanisms to characterize variations in fracture intensity within distinct regions of the study area. Three key findings emerge from this investigation. First, due to the Hercynian thermal event, X-shaped conjugate faults display a disproportionately high degree of development compared to other primary fractures. Analyzing the mechanisms of formation and development of these X-shaped strike-slip faults reveals discernible differences in deformation characteristics between NW-trending and NE-trending faults, with the former exhibiting a greater propensity for fracture rupture and efficient oil-gas migration. Second, fault intersections are critical and efficient conduits for fluid accumulation and thereby contribute to reservoir formation. Lastly, exclusive of X-shaped conjugate faults, NE-trending faults exhibit the greatest propensity for oil and gas accumulation and migration. Collectively, these findings facilitate the identification of areas favorable for oil and gas migration and provide a crucial mechanical analysis that can inform the exploration and development of the Tahe Oilfield. [ABSTRACT FROM AUTHOR]

Lucaogou Formation is the main formation for tight oil exploration and development in Junggar Basin. In order to analyze the geological characteristics and distribution of favorable areas, the favorable areas were divided based on the analysis of organic matter type, total organic carbon(TOC) content, maturity, reservoir rock type and porosity and permeability, combined with the lower limit of reservoir formation and burial. The results show that the organic kerogen types of Lucaogou Formation are mainly type Ⅰ and type Ⅱ1, with TOC content ranging from 0. 16% to 13. 86%, average content above 3. 0%, and average content of calcareous mudstone is 3. 79% . The maturity of organic matter is between 0. 55% and 1. 35%, and the main body is more than 0. 8% . From west to east, the maturity of organic matter decreases gradually, and it has the characteristics of wide distribution and large thickness, including the upper and lower two “source sweet spots”, and the thickness of “the lower sweet spot” is larger than “the upper sweet spot”. Reservoir rock types are diverse, high-quality reservoirs are concentrated in transitional rocks, dolomitic siltstone is the main reservoir rock type, and the pore structure is dominated by fine pore throats, which are typical low porosity and ultra-low permeability reservoirs. The porethroat connectivity is good, and the reservoir porosity-permeability correlation is good. Combined with the lower limit of tight oil accumulation depth, the favorable exploration areas of the first and second member of the Upper Lucaogou Formation are divided. The favorable exploration areas of the second member of the Lucaogou Formation are mainly distributed in well J32-H-J25-J32-J22 in the southeast of the sag, and the favorable exploration areas of the first member of the Lucaogou Formation are mainly distributed in well J251-J32-J174 in the middle and south of the sag. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on the core and experimental data of CBM exploration wells in Jiergalangtu Depression, Jiergalangtu Depression tectonic evolution characteristics, comprehensive analysis of the coal rank, coal rock composition, coal seam thickness, gas content and porosity and other physical conditions were discussed in this paper, determining the advantageous blocks the depression in vertical and horizontal direction. Results show that the 3#, 4# and 5# of Klbs of Jiergalangtu Depression are the main coal-bearing strata in the longitudinal aspect, with a good gas bearing capacity of coal rocks, large accumulative thickness of coal seams, generally good physical properties of coal seams and good enrichment conditions. On the lateral, the depression region of CBM wells in coal seam coal rank, coal rock, coal seam thickness, gas content and porosity were comprehensively analyzed, determining the favorable block of 3#, 4# and 5# seam of Klbs of Jiergalangtu Depression, which is helpful to advance the exploration of the low rank CBM resources in Erlian Basin.

Abstract: The shales in the 2nd Member of Shanxi Formation in the east margin of the Ordos Basin were deposited in a marine-nonmarine transitional environment during the Permian. Based on the recent breakthroughs in the shale gas exploration and theoretical understandings on the shale gas of the study area, with a comparison to marine shale gas in the Sichuan Basin and marine-nonmarine transitional shale gas in the U.S., this study presents the geological characteristics and development potential of marine-nonmarine transitional gas in the study area. Four geological features are identified in the 2nd Member of the Shanxi Formation in the study area has: (1) stable sedimentary environment is conductive to deposition of widely distributed organic shale; (2) well-developed micro- and nano- scale pore and fracture systems, providing good storage capacity; (3) high content of brittle minerals such as quartz, leading to effectively reservoir fracturing; and (4) moderate reservoir pressure and relatively high gas content, allowing efficient development of shale gas. The 2nd Member of Shanxi Formation in the east margin of Ordos Basin is rich in shale gas resource. Three favorable zones, Yulin-Linxian, Shiloubei-Daning-Jixian, and Hancheng-Huangling are developed, with a total area of 1.28×104 km2 and resources between 1.8×1012 and 2.9×1012 m3, indicating a huge exploration potential. Tests of the 2nd Member of Shanxi Formation in vertical wells show that the favorable intervals have stable gas production and high reserves controlled by single well, good recoverability and fracability. This shale interval has sufficient energy, stable production capacity, and good development prospects, as evidenced by systematic well testing. The east margin of the Ordos Basin has several shale intervals in the Shanxi and Taiyuan formations, and several coal seams interbedded, so collaborative production of different types of natural gas in different intervals can be considered. The study results can provide reference for shale gas exploration and development and promote the rapid exploitation of shale gas in China.

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Shale gas has become one of the hot spots of energy research in the world. The marine shale in the upper-middle Yangtze area of southern Sichuan has always been an important field of shale gas research in China. As a new unconventional energy source, the geological surveys have revealed that the marine shale in the upper-middle Yangtze area of southern Sichuan has a large amount of shale gas resources. On the basis of analyzing the characteristics of Longmaxi Formation reservoirs, this paper predicts and evaluates the Longmaxi Formation shale gas in southern my country based on the analytic hierarchy process. The following conclusions are drawn from this study: All high-quality reservoirs in the Longmaxi Formation are deposited in semi-deep to deep-sea sedimentary areas, with high organic carbon content and well-developed reservoir spatial characteristics, which allows the formation of a good closure sequence, deposition environment, and pore structure. Structural style and reservoir overpressure are the main controlling factors affecting natural gas enrichment. The enrichment method of the Longmaxi Formation in the Middle Yangtze area is closely related to the reservoir characteristics. The Longmaxi Formation is a neritic deposit related to the source rock development conditions. The analytic hierarchy process establishes a fuzzy comprehensive scoring system, calculates the membership degree of comments in each block, and covers the results of multi-regional surveys. The Longmaxi Formation is the highest in Fuling and southern Sichuan, followed by eastern Henan and Central Yangtze. [ABSTRACT FROM AUTHOR]

Introduction The Urmia-Naqadeh-Mahabad basin is a part of the south and west Urmia Lake drainage basin that covers some parts of East-and-West Azerbaijan and northern Kurdistan. This study is the integration of geological, hydrological, remote sensing, geochemical and airborne geophysical data classifying promising areas that are related to sandstone type uranium (U) mineralization in Iran. Based on positive factors such as favorable source, host rocks and suitable hydrological pattern, this basin is a favorable basin in Iran. According to the characteristics of lithology, tectonic, sedimentary environment, geotectonics and etc. the basin could be classified into favorable, promising and possible subbasins for mineralization of U sandstone type. Material and methods Geological data show that this region is a part of the Sanandaj-Sirjan zone and consists of Precambrian metamorphic rocks which are covered by younger sedimentary and volcano-sedimentary rocks that are influenced by different metamorphic phases. More than 7597 stream sediment samples from the area have been analyzed for Se،V، Mo، As،Cu، Ag، Zn، Co، Ni، Pb، Ti، Th، Zr، P and Sn. The basin is divided into 11 individual sub-basins. Radiometric data of the basin have been acquisitioned during 1976-1978 by an Australian-German- French Company with line separation of 500 meters and 120 meters of nominal terrain clearance. Remote sensing data reveals that the western subbasin is suitable for sandstone type uranium mineralization. Based on geochemical evidences, the Au, Zn, Sn, As and Pb elements were enriched. Geophysical investigation reveals that the Eastern basin includes high amounts of U and low amounts of Th. Hydrogeological study demonstrates that the trend of groundwater is from the west to the east. Geochemical data revealed that we can divide the basin into 11 subbasins which are characterized as follows: 1. Ghara Aghaj (126 Km2), North to south trend is situated at the northern part of the basin. At this basin Ni, Co, Cu and V are reported but it is not related to mineralization. 2. Ghoma – Bezrgah (36 Km2). The East to the West trend is situated at the western part of the basin. At this basin Pb, As, Sn, Zn and Au are reported which can be related to skarn mineralization. 3. Piram – Shilan (342 Km2). At this basin Pb, Zn, As and Mo are reported which contain source rocks of uranium mineralization but there is no evidence of host rock and mineralization. 4. Pirestan1 (28 Km2). According to geological data a granitic body which can be the source of uranium mineralization and cretaceous volcanic rock outcropped. The fault system is weak by the north to the south trend. The anomalies of Pb, Mo, As and Sn are reported but there is no evidence of mineralization. 5. Kooh-e sabz poosh (34 Km2). Based on geological data half of the area is covered by granodioritic body which can be the source of uranium mineralization. The fault system has two trends (NE-SW and N-S). The anomalies of V, As, Mo and Co are reported but there is no evidence of mineralization. 6. Pirestan2 ((83 Km2). According to geological data a granitic and granodioritic body can be the source of uranium mineralization. The anomalies of Mo, Sn, Co, As and Zn are reported but there is no evidence of mineralization. 7. Chahar Taq (36 Km2). The fault system has the NE to SW trend and trusted mechanism. The anomalies of Zn, Ni and Au are reported but there is no evidence of mineralization. 8. Zaveh Kooh (111 Km2). The rock units have the NW to SE trend according to the Sanadaj-Sirjan trend. The anomalies of Pb, As, Sn, Mo, Ti, Cu, Ni and Au are reported but there is no evidence of uranium mineralization but there is some evidence of orogenic gold mineralization. 9. Saqqez-Baneh (465 Km2). The rock units have the NW to SE trend according to the Sanadaj-Sirjan trend. The anomalies of Co, Ti, Cu, Zn, Pb, Ni, Mo, Sn, Ag, Au and As are reported but there is no evidence of uranium mineralization and the same as the 8th subbasin there are known deposits of orogenic gold mineralization. 10. Charkeh (104 Km2). The rock units have the NW to SE trend. The anomalies of Zn, Mo, Sn, V, Ni, Au, As and Pb are reported but there is no evidence of mineralization. 11. Sheikh Ebrahim (38 Km2). The anomalies of Mo, Au, As and Pb are reported. The integration of the different layers shows that the prospecting area is suitable for future exploration of blind deposits. Geophysical data was processed and revealed those areas which have data. They can be classified into 5 different classes based on U and Th concentrations. The Hydrogeological data consist of EC, pH, Eh, DO and salinity. And the temperature was measured at the field by Sension 156 multimeter and was sent for ICP-MS analysis to the AMDEL and Applied Geological Research Center (Karaj) laboratories. Two samples were obtained from each well by Widel et al.’s (1998) method. One sample was analyzed for Ca2+، Mg2+، Na+، K+، CO32-، HCO3-، SO42-and Cl- and the other samples were analyzed for major and trace elements. At each basin charge, the discharge and the trend of underground water were defined. Results The results revealed that this basin contains alkaline magmatic rocks such as alkaline rhyolite and tuff which are situated in reduced shale and continental volcanic clastic rocks and can be the source of uranium at the study area. Besides these rocks, tuffaceous sandstone, metamorphose sandstone and young alluvial by the reduction condition can be the suitable hosts for mineralization. Based on geological, geochemical, hydrogeological and geophysical data, the western basin is suitable for sandstone type uranium deposit and also there is some evidence of mineralization.

The shales in the 2nd Member of Shanxi Formation in the east margin of the Ordos Basin were deposited in a marine-nonmarine transitional environment during the Permian. Based on the recent breakthroughs in the shale gas exploration and theoretical understandings on the shale gas of the study area, with a comparison to marine shale gas in the Sichuan Basin and marine-nonmarine transitional shale gas in the U.S., this study presents the geological characteristics and development potential of marine-nonmarine transitional gas in the study area. Four geological features are identified in the 2nd Member of the Shanxi Formation in the study area has: (1) stable sedimentary environment is conductive to deposition of widely distributed organic shale; (2) well-developed micro- and nano- scale pore and fracture systems, providing good storage capacity; (3) high content of brittle minerals such as quartz, leading to effectively reservoir fracturing; and (4) moderate reservoir pressure and relatively high gas content, allowing efficient development of shale gas. The 2nd Member of Shanxi Formation in the east margin of Ordos Basin is rich in shale gas resource. Three favorable zones, Yulin-Linxian, Shiloubei-Daning-Jixian, and Hancheng-Huangling are developed, with a total area of 1.28×104 km2 and resources between 1.8×1012 and 2.9×1012 m3, indicating a huge exploration potential. Tests of the 2nd Member of Shanxi Formation in vertical wells show that the favorable intervals have stable gas production and high reserves controlled by single well, good recoverability and fracability. This shale interval has sufficient energy, stable production capacity, and good development prospects, as evidenced by systematic well testing. The east margin of the Ordos Basin has several shale intervals in the Shanxi and Taiyuan formations, and several coal seams interbedded, so collaborative production of different types of natural gas in different intervals can be considered. The study results can provide reference for shale gas exploration and development and promote the rapid exploitation of shale gas in China. [ABSTRACT FROM AUTHOR]

The Longtan Formation of the Upper Permian in the southwestern Guizhou Province is widely exposed in the area. From the northwest to the southeast, there are terrestrial, sea-continental and marine sediments with thicknesses ranging from 0 to 543 m. The mudstone intervals are thicker. Good shale gas reservoir conditions. Through the reservoir characteristics of the Upper Permian Longtan Formation shale in the southwestern Guizhou and the kerogen (soul group and vitrinite, chitin group, inertin group), organic carbon content (TOC) and organic maturity (Ro) and other analytical studies. The results show that the organic matter types of the shale in the Longtan Formation are mainly type II2, and II1 and III are present. The organic carbon content is 4.54% on average and the organic carbon content is very good. The maturity of organic matter averaged 2.03%, and the degree of evolution was generally higher. The Longtan Formation mud shale has low porosity and low permeability, and the water medium has a certain softening effect on rock strength. The favorable area is mainly located in the east of the Shuicheng- Pu'an-Xingyi line. [ABSTRACT FROM AUTHOR]

In terms of the geological characteristics of multiple coal seams,high crustal stress and complex tectonic in eastern Yunnan and western Guizhou, the concept of favorable area, dessert area and vertical dessert in the process of coalbed methane(CBM) geological selection was put forward, and the relationship of “Hierarchical progressive” between the three was clarified. The favorable area refers to the favorable syncline in a number of secondary syncline. The dessert area refers to the “target area” for the development of CBM from favorable syncline. The vertical dessert is a vertical optimization of the combination layer in the “target area” of CBM development. The key indexes of CBM geological resources, geological resources abundance and recoverable resources were put forward in the optimization index system of favorable area aimed at the characteristics of a large of secondary syncline, great difference in many parameters and exploration degree. The amount of CBM geological resources and the abundance of CBM geological resources are one vote veto. The key indexes of fault fractal dimension, tectonic curvature and buried depth were proposed in the optimization index system of the dessert area aimed at the characteristics of complex tectonic and high crustal stress in the study area. The fractal dimension value of the fault is one vote veto. The key indexes of coal structure, critical desorption pressure difference and reservoir pressure gradient difference were put forward in the optimization index system of the vertical dessert aimed at the characteristics of the development of multiple coal seams and the interlayer interference in the study area. The coal structure is one vote veto.In all stages, the corresponding reference indexes were put forward. Finally, the index system of CBM geological selection for the characteristics of the study area was constructed. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In north-west Jiangxi, China, most shale-gas exploration has been focused on the Lower Cambrian Hetang and Guanyintang formations, whereas the Upper Ordovician Xinkailing formation shale has been ignored for years due to heavy weathering. This study systematically analyzed gas source conditions, reservoir conditions and gas-bearing ability in order to reveal the shale-gas accumulation conditions of the Xinkailing formation. The results show that the Xinkailing formation is characterized by thick deposition of black shale (10–80 m), high organic content (with total organic carbon between 1.18% and 3.11%, on average greater than 2%), relatively moderate thermal evolution (with vitrinite reflectance between 2.83% and 3.21%), high brittle-mineral content (greater than 40%), abundant nanopores and micro-fractures, very good adsorption ability (adsorption content between 2.12m3/t and 3.47m3/t, on average about 2.50m3/t), and strong sealing ability in the underlying and overlying layers, all of which favor the generation and accumulation of shale gas. TheWuning-Lixi and Jinkou-Zhelin areas of the Xinkailing formation were selected as the most realistic and favorable targets for shale-gas exploration and exploitation. In conclusion, the Wuning area has great potential and can provide a breakthrough in shale gas with further investigation. [ABSTRACT FROM AUTHOR]

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study presents research concerning subterranean termites found in the Centre-Val de Loire region. More specifically, we examined the geographical distribution of Reticulitermes flavipes, a globally invasive species. This work was conducted in collaboration with both social and life science specialists in order to better understand the factors mediating its spatial distribution. Using geomatics and the spatial analysis of R. flavipes’ distribution, we were able to define geographical areas favorable to the termite. This geographical study and the diversity of players involved in this research underscore a growing awareness of termite invasion risks in society at large.

The Songliao Basin is a large-scale petroliferous basin in China. With a gradual decline in conventional oil production, the exploration and development of replacement resources in the basin is becoming increasingly important. Previous studies have shown that the Cretaceous Qingshankou Formation (K 2 qn) has favorable geological conditions for the formation of shale oil. Thus, shale oil in the Qingshankou Formation represents a promising and practical replacement resource for conventional oil. In this study, geological field surveys, core observation, sample tests, and the analysis of well logs were applied to study the geochemical and reservoir characteristics of shales, identify shale oil beds, build shale oil enrichment models, and classify favorable exploration areas of shale oil from the Cretaceous Qingshankou Formation. The organic matter content is high in shales from the first member of the Cretaceous Qingshankou Formation (K 2 qn 1 ), with average total organic carbon (TOC) content exceeding 2%. The organic matter is mainly derived from lower aquatic organisms in a reducing brackish to fresh water environment, resulting in mostly type I kerogen. The vitrinite reflectance (Ro) and the temperature at which the maximum is release of hydrocarbons from cracking of kerogen occurred during pyrolysis ( T max ) respectively range from 0.5% to 1.1% and from 430 °C to 450 °C, indicating that the K 2 qn 1 shales are in the low-mature to mature stage (Ro ranges from 0.5% to 1.2%) and currently generating a large amount of oil. The favorable depth for oil generation and expulsion is 1800–2200 m and 1900–2500 m, respectively as determined by basin modeling. The reserving space of the K 2 qn 1 shale oil includes micropores and mircofractures. The micropore reservoirs are developed in shales interbedded with siltstones exhibiting high gamma ray (GR), high resistivity (Rt), low density (DEN), and slightly abnormal spontaneous potential (SP) in the well-logging curves. The microfracture reservoirs are mainly thick shales with high Rt, high AC (acoustic transit time), high GR, low DEN, and abnormal SP. Based on the shale distribution, geochemical characteristics, reservoir types, fracture development, and the process of shale oil generation and enrichment, the southern Taikang and northern Da'an are classified as two favorable shale oil exploration areas in the Songliao Basin. [ABSTRACT FROM AUTHOR]

In north-west Jiangxi, China, most shale-gas exploration has been focused on the Lower Cambrian Hetang and Guanyintang formations, whereas the Upper Ordovician Xinkailing formation shale has been ignored for years due to heavy weathering. This study systematically analyzed gas source conditions, reservoir conditions and gas-bearing ability in order to reveal the shale-gas accumulation conditions of the Xinkailing formation. The results show that the Xinkailing formation is characterized by thick deposition of black shale (10–80 m), high organic content (with total organic carbon between 1.18% and 3.11%, on average greater than 2%), relatively moderate thermal evolution (with vitrinite reflectance between 2.83% and 3.21%), high brittle-mineral content (greater than 40%), abundant nanopores and micro-fractures, very good adsorption ability (adsorption content between 2.12 m3/t and 3.47 m3/t, on average about 2.50 m3/t), and strong sealing ability in the underlying and overlying layers, all of which favor the generation and accumulation of shale gas. The Wuning-Lixi and Jinkou-Zhelin areas of the Xinkailing formation were selected as the most realistic and favorable targets for shale-gas exploration and exploitation. In conclusion, the Wuning area has great potential and can provide a breakthrough in shale gas with further investigation.

Based on sequence stratigraphy, the Lower Ordovician in the eastern part of North China Platform can be divided into two Ⅲ-type sequences, which belong to Xinchangian stage and Daobaowanian stage, respectively. During Early Ordovician, there are two types of sedimentary environments including shallow sea and coastal deposit environments with shallow sea water. The archicontinent marginal sedimentary transits to carbonate platform sedimentary from south to north, and the restricted platform and supratidal dolomitic flat develop. Due to the tectogenetic inconsistency of platform, the differential uplift and depression are magnified between the south and the north as well as a continuous regression, moreover, the subsidence-sedimentary center extends from the latitudinal direction to the longitudinal direction. There is comprehensive action of various tectonic stresses and predominant direction. Relative sea level inherits the decrease in the end of Cambrian, and the regression happens from NW to SE. Dolomitic flat and restricted platform expand eastward, thus open platform retreats northward and eastward. The sedimentary facies is divided into south part and north part, so that the partition of lithology is significant, and the limestone transits to dolomite from platform to tidal flat. Specially, the penecontemporaneous dolomite of dolomitic flat subfacies develops, and the dolomite from Liangjiashan Formation of Lower Ordovician can act as high-quality reservoir in Meso-Cenozoic basin. [ABSTRACT FROM AUTHOR]

Upper Permian-Low Triassic carbonate formations in Sichuan Basin enrich gas,and the distribution of gas accumulation is controlled by high quality source rocks and reef-shoal facies reservoir.In order to reveal the gas enrichment rule and forecast the favorable areas under the sedimentary evolution settings in Sichuan Basin,the geological structure settings of Late Permian-Early Triassic Yangtze palaeoslab were analyzed,and the characteristics of Late Permian-Early Triassic sedimentary evolution under the geological structure settings were discussed;the development mechanism and distribution of high quality source rocks and reservoirs were explained according to the characteristics of tectonic evolution in differentperiods;combined with the gas accumulation model,the favorable areas of gas accumulation were divided.The results show that the development evolution of Late Permian-Early Triassic bay and shelf in Sichuan Basin controls the development and distribution of major source rocks in Longtan Formation and reef-shoal facies reservoirs in Changxing Formation-Feixianguan Formation,and the lower-generating and upper-reservoiring are favorable source-reservoir matching combination;the platform margin reef-shoal facies reservoir in Changxing Formation-Feixianguan Formation of Northeast Sichuan nearby the high quality source rocks of bay facies in Longtan Formation is the most favorable area for gas accumulation.In general,the characteristics of Late Permian-Early Triassic sedimentary evolution in Sichuan Basin control the development and distribution of marine facies high quality source rocks and reservoirs,and then determine the enrichment and distribution of gas. [ABSTRACT FROM AUTHOR]