Pub Date : 2022-08-01DOI: 10.1016/j.jnggs.2022.08.005
Jixian Tian , Baoqiang Ji , Xu Zeng , Yetong Wang , Yaoliang Li , Guoqiang Sun
The deep strata of the northern margin of the Qaidam Basin are currently unexplored and have high resource potential. To clarify the characteristics and control factors of the deep sandstone reservoir in the study area, a comprehensive investigation of the Xiaganchaigou Formation deep reservoir in the northern Qaidam margin is carried out using the casting thin section, SEM, porosity and permeability measurements, and well logging and mud logging data. The results show that the feldspar lithic sandstone and lithic feldspar sandstone, which are well sorted and medium-rounded and have high compositional and textural maturities, make up the majority of the deep reservoir rock of the Xiaganchaigou Formation in the northern Qaidam margin. Extensive development of primary pores is observed and the porosity and permeability are well correlated with each other, with the average porosity and permeability of 10.7% and 25.74 × 10−3 μm2, respectively. The pore-throat has excellent connectivity and is medium-fine in texture. The sands of the braided river delta front underwater distributary channel deposition and the sheet sands of the shore-shallow lake deposition are the basis for the formation of high-quality reservoirs. The carbonate cement is subjected to prolonged early shallow burial and late rapid burial during the diagenesis, effectively protecting primary pores. Feldspar particles and early carbonate cement are partially dissolved during the telodiagenesis, improving the physical properties of the reservoir by generating a certain number of inter- and intra-granular dissolved pores. Thick mudstone layers are deposited both above and below the sandstone reservoir. The drainage of pore fluids from the sandstone reservoir is therefore suppressed during the deposition-diagenesis and rapid burial, trapping the fluids in the pore space to bear part of the overburden pressure. This reduces the effects of normal compaction on the reservoir rock and helps in the preservation of primary pores to a large extent. The abnormal pressure zone in the Palaeogene Xiaganchaigou Formation, which develops the under-compacted mudstone of the braided river delta deposition, is found in the central part of the northern Qaidam margin and is afavorable play for natural gas exploration and development.
{"title":"Development characteristics and main control factors of deep clastic reservoirs of the Xiaganchaigou Formation in the northern marin of the Qaidam Basin, China","authors":"Jixian Tian , Baoqiang Ji , Xu Zeng , Yetong Wang , Yaoliang Li , Guoqiang Sun","doi":"10.1016/j.jnggs.2022.08.005","DOIUrl":"10.1016/j.jnggs.2022.08.005","url":null,"abstract":"<div><p>The deep strata of the northern margin of the Qaidam Basin are currently unexplored and have high resource potential. To clarify the characteristics and control factors of the deep sandstone reservoir in the study area, a comprehensive investigation of the Xiaganchaigou Formation deep reservoir in the northern Qaidam margin is carried out using the casting thin section, SEM, porosity and permeability measurements, and well logging and mud logging data. The results show that the feldspar lithic sandstone and lithic feldspar sandstone, which are well sorted and medium-rounded and have high compositional and textural maturities, make up the majority of the deep reservoir rock of the Xiaganchaigou Formation in the northern Qaidam margin. Extensive development of primary pores is observed and the porosity and permeability are well correlated with each other, with the average porosity and permeability of 10.7% and 25.74 × 10<sup>−3</sup> μm<sup>2</sup>, respectively. The pore-throat has excellent connectivity and is medium-fine in texture. The sands of the braided river delta front underwater distributary channel deposition and the sheet sands of the shore-shallow lake deposition are the basis for the formation of high-quality reservoirs. The carbonate cement is subjected to prolonged early shallow burial and late rapid burial during the diagenesis, effectively protecting primary pores. Feldspar particles and early carbonate cement are partially dissolved during the telodiagenesis, improving the physical properties of the reservoir by generating a certain number of inter- and intra-granular dissolved pores. Thick mudstone layers are deposited both above and below the sandstone reservoir. The drainage of pore fluids from the sandstone reservoir is therefore suppressed during the deposition-diagenesis and rapid burial, trapping the fluids in the pore space to bear part of the overburden pressure. This reduces the effects of normal compaction on the reservoir rock and helps in the preservation of primary pores to a large extent. The abnormal pressure zone in the Palaeogene Xiaganchaigou Formation, which develops the under-compacted mudstone of the braided river delta deposition, is found in the central part of the northern Qaidam margin and is afavorable play for natural gas exploration and development.</p></div>","PeriodicalId":100808,"journal":{"name":"Journal of Natural Gas Geoscience","volume":"7 4","pages":"Pages 225-235"},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2468256X2200044X/pdfft?md5=7812710ad6bab967712afe277444bd51&pid=1-s2.0-S2468256X2200044X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91542210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-01DOI: 10.1016/j.jnggs.2022.08.002
Jianying Guo , Xuening Qi , Lianhua Hou , Aisheng Hao , Xu Zeng , Shiguo Lin , Xiugang Pu , Zengye Xie , Yifeng Wang , Xiaobo Wang , Dawei Chen
Ultra-low permeability–tight sandstone (gravel) gas reservoir is an important exploration target for natural gas both domestically and internationally. As a crucial oil and gas exploration basin in China, the Bohai Bay Basin has discovered tight sandstone (gravel) gas in every depression. However, the distribution, origin, and accumulation model of tight sandstone (gravel) gas reservoirs were not systematically studied by previous researchers, who instead mainly concentrated on depressions from the basin-wide perspective. The research conclusively demonstrates that ultra-low permeability–tight sandstone (gravel) gas reservoirs are widely distributed in the Bohai Bay Basin, covering various depressions and multiple strata of Paleozoic, Cenozoic, and Upper Paleozoic coal-formed gas as well as Paleogene oil-type gas. The Upper Paleozoic ultra-low permeability–tight sandstone gas reservoirs are mainly distributed in residual Upper Paleozoic strata of the Huanghua, Linqing, and Jiyang depressions. Most of those reservoirs, which are located in uplifted sag zones, are structural gas reservoirs, and because the strata were buried deeply in the past, most of the reservoirs have worse physical properties. This natural gas is typical coal-formed gas originating in Carboniferous and Permian, and others are Paleogene oil-type gas. Paleogene ultra-low permeability–tight gas reservoirs are widely distributed in all depressions, including the multiple strata in the Kongdian Formation and the second, third. and fourth members of the Shahejie Formation (Es2, Es3, and Es4); The gas reservoirs are located in the uplift, slope, and steep slope zones of the sags, including a variety of trap types, such as lithology, lithology-structure, structure reservoirs, and others. Sandstone reservoirs often found in the Es2 and Es3 are distributed in gentle slopes, whereas sandstone and glutenite reservoirs can be found in the Es4 and Kongdian Formation (Ek), with the glutenites mainly distributed in steep slope area. Since the Paleogene is a continuous deposit, burial depth appears to be a controlling factor in the reservoirs physical properties. Densification threshold depths for distinct depressions range from 3200 m to 4000 m. The majority of the natural gas is gas formed from Paleogene oil-type, while some of it is gas formed from Upper Paleozoic coal. Four different hydrocarbon accumulation models have been developed in this area in accordance with the relationship between gas sources and reservoirs. These models include migration along fault with old source rock and new reservoir, near-source accumulation with new source rock and new reservoir, distant-source accumulation with old source rock and old reservoir, and migration along fault with new source rock and old reservoir, of which the first two are the main hydrocarbon accumulation
{"title":"Origin and accumulation models of ultra-low permeability-tight sandstone (gravel) gas in Bohai Bay Basin, China","authors":"Jianying Guo , Xuening Qi , Lianhua Hou , Aisheng Hao , Xu Zeng , Shiguo Lin , Xiugang Pu , Zengye Xie , Yifeng Wang , Xiaobo Wang , Dawei Chen","doi":"10.1016/j.jnggs.2022.08.002","DOIUrl":"10.1016/j.jnggs.2022.08.002","url":null,"abstract":"<div><p>Ultra-low permeability–tight sandstone (gravel) gas reservoir is an important exploration target for natural gas both domestically and internationally. As a crucial oil and gas exploration basin in China, the Bohai Bay Basin has discovered tight sandstone (gravel) gas in every depression. However, the distribution, origin, and accumulation model of tight sandstone (gravel) gas reservoirs were not systematically studied by previous researchers, who instead mainly concentrated on depressions from the basin-wide perspective. The research conclusively demonstrates that ultra-low permeability–tight sandstone (gravel) gas reservoirs are widely distributed in the Bohai Bay Basin, covering various depressions and multiple strata of Paleozoic, Cenozoic, and Upper Paleozoic coal-formed gas as well as Paleogene oil-type gas. The Upper Paleozoic ultra-low permeability–tight sandstone gas reservoirs are mainly distributed in residual Upper Paleozoic strata of the Huanghua, Linqing, and Jiyang depressions. Most of those reservoirs, which are located in uplifted sag zones, are structural gas reservoirs, and because the strata were buried deeply in the past, most of the reservoirs have worse physical properties. This natural gas is typical coal-formed gas originating in Carboniferous and Permian, and others are Paleogene oil-type gas. Paleogene ultra-low permeability–tight gas reservoirs are widely distributed in all depressions, including the multiple strata in the Kongdian Formation and the second, third. and fourth members of the Shahejie Formation (E<em>s</em><sub>2</sub>, E<em>s</em><sub>3,</sub> and E<em>s</em><sub>4</sub>); The gas reservoirs are located in the uplift, slope, and steep slope zones of the sags, including a variety of trap types, such as lithology, lithology-structure, structure reservoirs, and others. Sandstone reservoirs often found in the E<em>s</em><sub>2</sub> and E<em>s</em><sub>3</sub> are distributed in gentle slopes, whereas sandstone and glutenite reservoirs can be found in the E<em>s</em><sub>4</sub> and Kongdian Formation (E<em>k</em>), with the glutenites mainly distributed in steep slope area. Since the Paleogene is a continuous deposit, burial depth appears to be a controlling factor in the reservoirs physical properties. Densification threshold depths for distinct depressions range from 3200 m to 4000 m. The majority of the natural gas is gas formed from Paleogene oil-type, while some of it is gas formed from Upper Paleozoic coal. Four different hydrocarbon accumulation models have been developed in this area in accordance with the relationship between gas sources and reservoirs. These models include migration along fault with old source rock and new reservoir, near-source accumulation with new source rock and new reservoir, distant-source accumulation with old source rock and old reservoir, and migration along fault with new source rock and old reservoir, of which the first two are the main hydrocarbon accumulation ","PeriodicalId":100808,"journal":{"name":"Journal of Natural Gas Geoscience","volume":"7 4","pages":"Pages 211-223"},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2468256X22000414/pdfft?md5=ad84b91ced813a40b3110a0ac50bbca6&pid=1-s2.0-S2468256X22000414-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84175911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-01DOI: 10.1016/j.jnggs.2022.08.004
Guoli Wang , Xiaobo Song , Yong Liu , Xianwu Meng , Ke Long
The Leikoupo Formation of the Middle Triassic is one of the hot strata of marine natural gas exploration in the western Sichuan Basin in recent years. Petroleum geologists have different opinions on the reservoir-forming conditions and the types of gas pools. The research shows that the 4th member of Leikoupo Formation in the western Sichuan Basin has favorable hydrocarbon accumulation conditions. It not only has a large-scale stable distribution of the tidal flat dolomite reservoirs, but also develops two sets of source rocks: the Permian source rock and the Leikoupo Formation source rock. There are three models of hydrocarbon accumulation in the 4th member of Leikoupo Formation from the east to the west in the Western Sichuan Depression. That is the “lower generation and upper storage” structural gas reservoir transported by cross-layer source faults and fractures, the “lower generation and upper storage” structure-formation gas reservoirs transported by the relay combination of small source faults and intra-layer fractures, and the “self-generating and self-accumulation” lithologic gas reservoir transported by intra-layer fractures. After the proved reserves of 100 × 109 m3 of the structural gas reservoir in the 4th member of Leikoupo Formation in the western Sichuan Basin, it is considered that the area near the pinch-out line of the 4th member of Leikoupo Formation in the eastern depression is a favorable area for exploration of tectonic-stratigraphical gas reservoirs, and the middle and lower part of the eastern slope (Guanghan slope) in the Western Sichuan Depression is a favorable area to explore lithologic gas reservoirs.
{"title":"Accumulation characteristics and exploration prospects of the 4th member of Leikoupo Formation in the western Sichuan Basin, China","authors":"Guoli Wang , Xiaobo Song , Yong Liu , Xianwu Meng , Ke Long","doi":"10.1016/j.jnggs.2022.08.004","DOIUrl":"10.1016/j.jnggs.2022.08.004","url":null,"abstract":"<div><p>The Leikoupo Formation of the Middle Triassic is one of the hot strata of marine natural gas exploration in the western Sichuan Basin in recent years. Petroleum geologists have different opinions on the reservoir-forming conditions and the types of gas pools. The research shows that the 4th member of Leikoupo Formation in the western Sichuan Basin has favorable hydrocarbon accumulation conditions. It not only has a large-scale stable distribution of the tidal flat dolomite reservoirs, but also develops two sets of source rocks: the Permian source rock and the Leikoupo Formation source rock. There are three models of hydrocarbon accumulation in the 4th member of Leikoupo Formation from the east to the west in the Western Sichuan Depression. That is the “lower generation and upper storage” structural gas reservoir transported by cross-layer source faults and fractures, the “lower generation and upper storage” structure-formation gas reservoirs transported by the relay combination of small source faults and intra-layer fractures, and the “self-generating and self-accumulation” lithologic gas reservoir transported by intra-layer fractures. After the proved reserves of 100 × 10<sup>9</sup> m<sup>3</sup> of the structural gas reservoir in the 4th member of Leikoupo Formation in the western Sichuan Basin, it is considered that the area near the pinch-out line of the 4th member of Leikoupo Formation in the eastern depression is a favorable area for exploration of tectonic-stratigraphical gas reservoirs, and the middle and lower part of the eastern slope (Guanghan slope) in the Western Sichuan Depression is a favorable area to explore lithologic gas reservoirs.</p></div>","PeriodicalId":100808,"journal":{"name":"Journal of Natural Gas Geoscience","volume":"7 4","pages":"Pages 199-210"},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2468256X22000438/pdfft?md5=7eeeca089ae548c9db504ab0769b523d&pid=1-s2.0-S2468256X22000438-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78286903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-01DOI: 10.1016/j.jnggs.2022.08.003
Yuman Wang , Guoqi Wei , Junjun Shen , Zhen Qiu , Xinjing Li , Qin Zhang , Leifu Zhang , Canhui Wang , Wen Liu
The distribution and main controlling factors of the organic matter carbonization points/zones of over-mature marine shale are important issues for shale gas exploration. This paper focuses on the Lower Cambrian and Lower Silurian shales in the Sichuan Basin and its periphery. Based on the detailed anatomy of key carbonization zones, predictions of shale organic matter carbonization zones and regional mapping of thermal maturity are carried out to explore and reveal the distribution and main controlling factors of the carbonization zones of organic matter in the two sets of shales. Four preliminary conclusions were obtained: (1) There are four organic matter carbonization zones in the Lower Silurian shale distribution area, namely eastern Sichuan-western Hubei, northwestern Hubei, west of southern Sichuan, and Renhuai-southwestern Chongqing, covering an area of nearly 40 × 103 km2. The main part of the western carbonization zone in the southern Sichuan is located in the Emei basalt distribution area. (2) The organic matter carbonization zone accounts for more than 80% of the Lower Cambrian shale distribution area, The non-carbonization zone is only distributed in Weiyuan-Ziyang, Moxi-Gaoshiti, Changyang, and Weng'an-Zhenyuan with an area of about 62.6 × 103 km2. (3) The Lower Silurian and Lower Cambrian shales in the west of southern Sichuan experienced an increase in thermal maturity RO values of 0.2%–0.4% and 0.2%–1.0%, respectively, as a result of the Emei large igneous province, an extreme heat event in the Late Permian. The Lower Cambrian and Lower Silurian shales have the highest degree of carbonization of organic matter in Mabian-Ebian, which is also in the high-value area of the Emei basalt thickness. (4) The main controlling factors of organic matter carbonization of the Lower Cambrian and Lower Silurian shales have similarities and differences. The main controlling factor of the former is the long-term deep burial background, and the extreme thermal event in the Late Permian only exacerbated the degree of carbonization in some areas more seriously. The latter's main controlling factors are relatively complex and are controlled by deep burial background in the three regions of Renhuai-southwestern Chongqing, eastern Sichuan-western Hubei, and northwestern Hubei. It was governed by a deep burial background and a high geotemperature in the Late Permian.
{"title":"Analysis on distribution and main controlling factors of OM carbonization in marine shale in the Sichuan Basin of China and its periphery","authors":"Yuman Wang , Guoqi Wei , Junjun Shen , Zhen Qiu , Xinjing Li , Qin Zhang , Leifu Zhang , Canhui Wang , Wen Liu","doi":"10.1016/j.jnggs.2022.08.003","DOIUrl":"10.1016/j.jnggs.2022.08.003","url":null,"abstract":"<div><p>The distribution and main controlling factors of the organic matter carbonization points/zones of over-mature marine shale are important issues for shale gas exploration. This paper focuses on the Lower Cambrian and Lower Silurian shales in the Sichuan Basin and its periphery. Based on the detailed anatomy of key carbonization zones, predictions of shale organic matter carbonization zones and regional mapping of thermal maturity are carried out to explore and reveal the distribution and main controlling factors of the carbonization zones of organic matter in the two sets of shales. Four preliminary conclusions were obtained: (1) There are four organic matter carbonization zones in the Lower Silurian shale distribution area, namely eastern Sichuan-western Hubei, northwestern Hubei, west of southern Sichuan, and Renhuai-southwestern Chongqing, covering an area of nearly 40 × 10<sup>3</sup> km<sup>2</sup>. The main part of the western carbonization zone in the southern Sichuan is located in the Emei basalt distribution area. (2) The organic matter carbonization zone accounts for more than 80% of the Lower Cambrian shale distribution area, The non-carbonization zone is only distributed in Weiyuan-Ziyang, Moxi-Gaoshiti, Changyang, and Weng'an-Zhenyuan with an area of about 62.6 × 10<sup>3</sup> km<sup>2</sup>. (3) The Lower Silurian and Lower Cambrian shales in the west of southern Sichuan experienced an increase in thermal maturity <em>R</em><sub>O</sub> values of 0.2%–0.4% and 0.2%–1.0%, respectively, as a result of the Emei large igneous province, an extreme heat event in the Late Permian. The Lower Cambrian and Lower Silurian shales have the highest degree of carbonization of organic matter in Mabian-Ebian, which is also in the high-value area of the Emei basalt thickness. (4) The main controlling factors of organic matter carbonization of the Lower Cambrian and Lower Silurian shales have similarities and differences. The main controlling factor of the former is the long-term deep burial background, and the extreme thermal event in the Late Permian only exacerbated the degree of carbonization in some areas more seriously. The latter's main controlling factors are relatively complex and are controlled by deep burial background in the three regions of Renhuai-southwestern Chongqing, eastern Sichuan-western Hubei, and northwestern Hubei. It was governed by a deep burial background and a high geotemperature in the Late Permian.</p></div>","PeriodicalId":100808,"journal":{"name":"Journal of Natural Gas Geoscience","volume":"7 4","pages":"Pages 181-197"},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2468256X22000426/pdfft?md5=290949ea936a9f954f61c16448a8895a&pid=1-s2.0-S2468256X22000426-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77146639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-01DOI: 10.1016/j.jnggs.2022.08.001
Zhenglin Cao, Pan Li, Ruiju Wang
During the P–T transition period (from the Late Permian to the Early Triassic), the Mahu Sag of the Junggar Basin transitioned from a foreland basin to a large depression lake basin, with the development of two sets of unconformities (T1/P and P3w/P2w) and two sets of lowstand deposits, the upper Wuerhe Formation (P3w) and the Baikouquan Formation (T1b) that now host a series of large or giant conglomerate oil fields. For the two third-order sequence boundaries T1/P and P3w/P2w, two types of slope-break zones associated with flexure or erosion have been identified: the flexural slope-break zone controlled by a persistent paleo-uplift that also controls the layer-by-layer “unidirectional onlapping” of strata above the sequence boundary towards the higher part of the slope; and the erosional slope-break zone controlled by the erosional remnants of paleo-mounds, typically characterized by “two-way onlapping” towards the residual mounds or filling along the lower part of the valleys. Both types of slope-break zones control stratigraphy and sedimentary changes, and they encourage the formation of lithostratigraphic traps of up-dip onlapping, lowstand filling, and truncated types. The findings have a significant impact on the exploration of large-scale lithostratigraphic plays controlled by paleotopography.
{"title":"Sequence architecture, slope-break development and geological significance during the P–T transition in the Mahu Sag, Junggar Basin, China","authors":"Zhenglin Cao, Pan Li, Ruiju Wang","doi":"10.1016/j.jnggs.2022.08.001","DOIUrl":"10.1016/j.jnggs.2022.08.001","url":null,"abstract":"<div><p>During the P–T transition period (from the Late Permian to the Early Triassic), the Mahu Sag of the Junggar Basin transitioned from a foreland basin to a large depression lake basin, with the development of two sets of unconformities (T<sub>1</sub>/P and P<sub>3</sub><em>w</em>/P<sub>2</sub><em>w</em>) and two sets of lowstand deposits, the upper Wuerhe Formation (P<sub>3</sub><em>w</em>) and the Baikouquan Formation (T<sub>1</sub><em>b</em>) that now host a series of large or giant conglomerate oil fields. For the two third-order sequence boundaries T<sub>1</sub>/P and P<sub>3</sub><em>w</em>/P<sub>2</sub><em>w</em>, two types of slope-break zones associated with flexure or erosion have been identified: the flexural slope-break zone controlled by a persistent paleo-uplift that also controls the layer-by-layer “unidirectional onlapping” of strata above the sequence boundary towards the higher part of the slope; and the erosional slope-break zone controlled by the erosional remnants of paleo-mounds, typically characterized by “two-way onlapping” towards the residual mounds or filling along the lower part of the valleys. Both types of slope-break zones control stratigraphy and sedimentary changes, and they encourage the formation of lithostratigraphic traps of up-dip onlapping, lowstand filling, and truncated types. The findings have a significant impact on the exploration of large-scale lithostratigraphic plays controlled by paleotopography.</p></div>","PeriodicalId":100808,"journal":{"name":"Journal of Natural Gas Geoscience","volume":"7 4","pages":"Pages 237-248"},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2468256X22000402/pdfft?md5=4840d3c9ff283046619791f7ee27f5b0&pid=1-s2.0-S2468256X22000402-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89170175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-01DOI: 10.1016/j.jnggs.2022.06.004
Q. Zhang, Zhen Qiu, Leifu Zhang, Yuman Wang, Yufeng Xiao, Dan Liu, Wen Liu, Shuxin Li, Xingtao Li
{"title":"Characteristics and controlling factors of transitional shale gas reservoirs: An example from Permian Shanxi Formation, Daning-Jixian block, Ordos Basin, China","authors":"Q. Zhang, Zhen Qiu, Leifu Zhang, Yuman Wang, Yufeng Xiao, Dan Liu, Wen Liu, Shuxin Li, Xingtao Li","doi":"10.1016/j.jnggs.2022.06.004","DOIUrl":"https://doi.org/10.1016/j.jnggs.2022.06.004","url":null,"abstract":"","PeriodicalId":100808,"journal":{"name":"Journal of Natural Gas Geoscience","volume":"56 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84658634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-01DOI: 10.1016/j.jnggs.2022.06.003
Lei Yan, G. Wei, G. Zhu, Yongquan Chen, Caiming Luo, M. Yang, Sha Wang, Dedao Du
{"title":"Exploration field analysis and zone optimization of sinian, Tarim Basin, China","authors":"Lei Yan, G. Wei, G. Zhu, Yongquan Chen, Caiming Luo, M. Yang, Sha Wang, Dedao Du","doi":"10.1016/j.jnggs.2022.06.003","DOIUrl":"https://doi.org/10.1016/j.jnggs.2022.06.003","url":null,"abstract":"","PeriodicalId":100808,"journal":{"name":"Journal of Natural Gas Geoscience","volume":"423 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86069953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-01DOI: 10.1016/j.jnggs.2022.06.002
Jianfeng Li, L. Kong, Kai Wu, Jun Ma, Fei Liu, Man Liu
{"title":"Genesis of H2S in Jurassic associated gas in Pengyang area, Ordos Basin, NW China","authors":"Jianfeng Li, L. Kong, Kai Wu, Jun Ma, Fei Liu, Man Liu","doi":"10.1016/j.jnggs.2022.06.002","DOIUrl":"https://doi.org/10.1016/j.jnggs.2022.06.002","url":null,"abstract":"","PeriodicalId":100808,"journal":{"name":"Journal of Natural Gas Geoscience","volume":"53 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76310761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-01DOI: 10.1016/j.jnggs.2022.06.002
Jianfeng Li , Lingyin Kong , Kai Wu , Jun Ma , Fei Liu , Man Liu
The Jurassic Yan'an Formation (J1y) crude oil-associated gas in the Pengyang area of the Ordos Basin contains a certain amount of H2S. The study of its genesis is important for us to predict the distribution of H2S in Mesozoic in the basin. The Chang7 source rock of the Yanchang Formation (T3y) is the principal source of crude oil in the Jurassic Yan'an Formation area. However, H2S is not detected in the crude oil-associated gas of Chang10 to Chang3 members of the Yanchang Formation. As a result, the formation of H2S in the crude oil-associated gas of Yan'an Formation may be related to reservoir and accumulation factors. The study shows that Jurassic formation water has a high salinity and is rich in divalent sulfur, which inhibits the development of sulfate-reducing bacteria (SRB). It is less likely to biologically reduce sulfate to produce H2S. The δ34S values of H2S in crude oil-associated gas of Yan'an Formation are greater than 25‰, which are obviously different from those of volcanic hydrothermal fluid, organic matter, and microbial reduction products, but similar to divalent sulfur isotope values in formation water and about 10‰ negative to sulfate ion in formation water. TSR has generated sulfur isotope distribution and fractionation characteristics in H2S. The temperature measurement of reservoir inclusions in the Jurassic Yan'an Formation shows that the initial filling temperature of oil and gas is higher than 100 °C, and the maximum accumulation forming temperature is 150 °C. The formation water of Yan'an Formation contains a large number of sulfate ions from anhydrite or buried stage. Those rich sulfate ions meet the conditions for a sulfate thermochemical reduction reaction. At the same time, the rich magnesium ions in formation water catalyzed the reaction. Therefore, H2S in Jurassic crude oil-associated gas in the Pengyang area of the Ordos Basin has thermochemical sulfate reduction (TSR) genesis.
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