- Article List
- Full Abstracts
-
Connotation,evaluation and optimization of tight oil sweet spots: A case study of Cretaceous Xiagou Formation in Qingxi Sag,Jiuquan Basin
LUO Qun, ZHANG Zeyuan, YUAN Zhenzhu, XU Qian, QIN Wei
2022, Vol.34(4): 1–12
Abstract
(
401 )
HTML
(1 KB)
PDFEN
( KB)
(
378
)
-
Seismic description technologies of Neogene composite channel sand bodies in Kenli 6-1 oilfield,Bohai Sea
ZHOU Donghong, TAN Huihuang, ZHANG Shengqiang
2022, Vol.34(4): 13–21
Abstract
(
374 )
HTML
(0 KB)
PDFEN
(5265 KB)
(
376
)
-
Seismic response characteristics and distribution law of carbonate shoals of Cambrian Canglangpu Formation in Gaoshiti-Moxi area,Sichuan Basin
LI Shanshan, JIANG Pengfei, LIU Lei, LEI Cheng, ZENG Yunxian, CHEN Shizhen, ZHOU Gang
2022, Vol.34(4): 22–31
Abstract
(
366 )
HTML
(0 KB)
PDFEN
(6041 KB)
(
160
)
-
Evolution characteristics of thermal expansion coefficient of rocks with temperature of Triassic Chang 7 organic-rich reservoir and its implications in Ordos Basin
ZHANG Yan, HOU Lianhua, CUI Jingwei, LUO Xia, LIN Senhu, ZHANG Ziyun
2022, Vol.34(4): 32–41
Abstract
(
362 )
HTML
(0 KB)
PDFEN
(4941 KB)
(
226
)
-
Seismic identification and gas-bearing prediction of large-scale submarine fans of Neogene Huangliu Formation in D13 area of Yinggehai Basin
WANG Lifeng, SONG Ruiyou, CHEN Dianyuan, XU Tao, PAN Guangchao, HAN Guangming
2022, Vol.34(4): 42–52
Abstract
(
326 )
HTML
(0 KB)
PDFEN
(10838 KB)
(
201
)
-
Lithofacies types and reservoir characteristics of shales of Jurassic Da'anzhai member in central Sichuan Basin
KANG Jiahao, WANG Xingzhi, XIE Shengyang, ZENG Deming, DU Yao, ZHANG Rui, ZHANG Shaomin, LI Yang
2022, Vol.34(4): 53–65
Abstract
(
303 )
HTML
(0 KB)
PDFEN
(9879 KB)
(
242
)
-
Reservoir characteristics and controlling factors of the second member of Paleogene Shahejie Formation in southeastern margin of Liaodong Sag
WANG Maozhen, WU Kui, GUO Tao, HUI Guanzhou, HAO Yiwei
2022, Vol.34(4): 66–78
Abstract
(
332 )
HTML
(0 KB)
PDFEN
(9319 KB)
(
217
)
-
Characteristics of Permian concealed structures in western margin of Ordos Basin and its significance for oil and gas exploration
YIN Yuyi, YAO Zhichun, GUO Xiaobo, WANG Leli, CHEN Siqian, YU Xiaolei, CEN Xiangyang
2022, Vol.34(4): 79–88
Abstract
(
359 )
HTML
(0 KB)
PDFEN
(6892 KB)
(
252
)
-
Quantitative characterization of pore structure of shale reservoirs of Permian Lucaogou Formation in Jimsar Sag
ZHANG Jigang, DU Meng, CHEN Chao, QIN Ming, JIA Ninghong, LYU Weifeng, DING Zhenhua, XIANG Yong
2022, Vol.34(4): 89–102
Abstract
(
368 )
HTML
(0 KB)
PDFEN
(16839 KB)
(
280
)
-
Reservoir characteristics and genesis of dolomite of Middle Permian Qixia Formation in southwestern Sichuan Basin
LI Rong, SU Chengpeng, JIA Huofu, SHI Guoshan, LIN Hui, LI Suhua
2022, Vol.34(4): 103–115
Abstract
(
305 )
HTML
(0 KB)
PDFEN
(13122 KB)
(
236
)
-
Hydrocarbon generation kinetics of source rocks of Permian Fengcheng Formation in Mahu Sag,Junggar Basin
BAI Yu, WANG Fei, NIU Zhijie, JIN Kailai, LI Peiyi, XU Duonian, CHEN Gangqiang
2022, Vol.34(4): 116–127
Abstract
(
403 )
HTML
(0 KB)
PDFEN
(4157 KB)
(
287
)
-
Sedimentary characteristics and source control of Lower Jurassic in coastal basins of East Africa
ZHANG Junlong, HE Youbin, LIANG Jianshe, QIU Chunguang, WU Dongsheng, LI Hua, TONG Le
2022, Vol.34(4): 128–140
Abstract
(
338 )
HTML
(0 KB)
PDFEN
(7671 KB)
(
284
)
-
Water-rock interaction in deep strata under high temperature and high pressure in Pearl River Mouth Basin
LI Chengze, CHEN Guojun, TIAN Bing, YUAN Xiaoyu, SUN Rui, SU Long
2022, Vol.34(4): 141–149
Abstract
(
281 )
HTML
(0 KB)
PDFEN
(4989 KB)
(
246
)
-
Oil-water flow law of Ordovician fractured-vuggy reservoirs in Tahe Oilfield
SONG Chuanzhen, MA Cuiyu
2022, Vol.34(4): 150–158
Abstract
(
310 )
HTML
(0 KB)
PDFEN
(4563 KB)
(
296
)
-
Reconstruction of 3D geological model of braided river sandstone reservoirs: A case study of Neogene Guantao Formation in Gaoshangpu block,Jidong Oilfield
LIU Yangping, WU Boran, YU Zhongliang, YU Chenglin, WANG Lixin, YIN Yanshu
2022, Vol.34(4): 159–170
Abstract
(
380 )
HTML
(0 KB)
PDFEN
(7895 KB)
(
249
)
-
Connotation,evaluation and optimization of tight oil sweet spots: A case study of Cretaceous Xiagou Formation in Qingxi Sag,Jiuquan Basin
LUO Qun, ZHANG Zeyuan, YUAN Zhenzhu, XU Qian, QIN Wei
2022, Vol.34(4): 1–12
Abstract
(
401 )
PDF (4321 KB) (
378
)
doi: https://doi.org/10.12108/yxyqc.20220401
The tight oil sweet spot is a core area for tight oil exploration and development. Through the study on the accumulation and enrichment law of Cretaceous tight oil reservoirs in Qingxi Sag,Jiuquan Basin,the connotation,evaluation and optimization methods of tight oil sweet spots were revealed. The results show that:(1)Tight oil sweet spots are relatively high abundance oil-bearing areas(or strata)under the overall low abundance oil-bearing background in fine-grained sedimentary system of petroliferous basin. Tight oil sweet spots can be divided into five categories:physical sweet spot,reservoir sweet spot,engineering sweet spot,productivity sweet spot and economic sweet spot. Physical sweet spot and reservoir sweet spot are collectively referred to as geological sweet spot.(2)The main geological factors controlling tight oil sweet spots include lithology combination characteristics,source and reservoir quality,source reservoir assemblage and fracture development degree.(3)The evaluation and optimization methods of tight oil sweet spots are:high-quality source rocks and Ro determining tight oil distribution,source-reservoir assemblage determining favorable tight oil zones,the matching of four excellent factors(high quality source rocks,high quality reservoirs,well-developed fractures and favorable matching of these factors in time and space)determining tight oil sweet spot,and multi-layer superimposition determining tight oil exploration and development well trajectory.
-
Seismic description technologies of Neogene composite channel sand bodies in Kenli 6-1 oilfield,Bohai Sea
ZHOU Donghong, TAN Huihuang, ZHANG Shengqiang
2022, Vol.34(4): 13–21
Abstract
(
374 )
PDF (5265 KB) (
376
)
doi: https://doi.org/10.12108/yxyqc.20220402
The shallow Neogene composite channel sand bodies are important reservoirs in Bohai oilfield. Based on well logging-to-seismic integration data of Kenli 6-1 oilfield in Laibei area,gather optimization was carried out to improve the amplitude-preserved properties of pre-stack gathers,and fine seismic description and fluid detection of thin interbedded sand bodies were completed. The results show that:(1)The AVO correction method in time-frequency space domain with low-frequency constraints effectively improves the AVO amplitude-preserved properties of pre-stack gathers in the study area.(2)The iterative frequency-divided stochastic inversion technology constrained by three-dimensional sand to stratum ratio realizes fine characterization of the superposition relationship of Neogene composite sand bodies and the accurate calculation of reservoir thickness in the study area. (3)The fluid detection technology with three-parameter constraint can weaken the influence of non-hydrocarbon anomalies,enhance the matching degree between seismic fluid anomalies and tectonic high and low information,and greatly improve the coincidence rate of seismic fluid detection in the study area,so as to improve the success rate of lithologic reservoir exploration.
-
Seismic response characteristics and distribution law of carbonate shoals of Cambrian Canglangpu Formation in Gaoshiti-Moxi area,Sichuan Basin
LI Shanshan, JIANG Pengfei, LIU Lei, LEI Cheng, ZENG Yunxian, CHEN Shizhen, ZHOU Gang
2022, Vol.34(4): 22–31
Abstract
(
366 )
PDF (6041 KB) (
160
)
doi: https://doi.org/10.12108/yxyqc.20220403
The Cambrian Canglangpu Formation in Sichuan Basin has good accumulation conditions and great exploration prospects. Based on the data of cores,three-dimensional seismic,drilling and logging,and through the combination of geology and geophysics,the seismic reflection characteristics and sedimentary characteristics of shoals of Canglangpu Formation in Gaomo area were studied. The results show that:(1)Four kinds of seismic reflection characteristics can be identified in Cambrian Canglangpu Formation in Gaoshiti-moxi area,corresponding to four types of sedimentary microfacies combination,among which the shoals corresponding to strong amplitude,low frequency and high continuous reflection is the most developed.(2)Shoals developed in the upper part of the first member of Canglangpu Formation,distributed in eastern Gaomo fault,and spread out in NEE and NNW direction around the wings of two paleo-uplift,with a striped or irregular shape,and the long axis direction is nearly parallel to the paleo-uplift boundary.(3)During the sedimentary period of Canglangpu Formation,Gaomo area was in shallow sea shelf facies as a whole,and large number of carbonate shoals were developed. The development and distribution of shoals are mainly controlled by sea level changes,paleogeomorphology and source supply at the sedimentary period.
-
Evolution characteristics of thermal expansion coefficient of rocks with temperature of Triassic Chang 7 organic-rich reservoir and its implications in Ordos Basin
ZHANG Yan, HOU Lianhua, CUI Jingwei, LUO Xia, LIN Senhu, ZHANG Ziyun
2022, Vol.34(4): 32–41
Abstract
(
362 )
PDF (4941 KB) (
226
)
doi: https://doi.org/10.12108/yxyqc.20220404
In-situ conversion processing(ICP)of shale underground is an effective and feasible option to realize the size development and utilization of medium to low-mature shale oil. The study of thermal expansion of shale during heating is of great significance for the engineering evaluation of wellbore stability,heater life and cap rock integrity. The thermal expansion coefficients and dynamic evolution characteristics of muddy siltstone,mudstone and shale at 25-600℃ were obtained by using DIL402 SE instrument on the basis of thin section observation and X-ray diffraction analysis of cores from three wells of Triassic Chang 7 shale layer in Ordos Basin. The results show that:(1)The thermal expansion coefficients of rocks with different lithologies in the study area differ greatly and increase with the increase of organic carbon content. The thermal expansion coefficients of rocks with TOC being less than 5% increase almost exponentially,while the thermal expansion coefficients of rocks with TOC being greater than or equal to 5% show a "four stage" complex change.(2)The anisotropy factor of the thermal expansion coefficients of organic-rich shale in the study area is the largest,which is 1.7-2.7 times in vertical bedding direction than that in parallel bedding direction.(3)The high hydrocarbon generation intensity of organic-rich shale can cause microfractures and lead to complex changes in thermal expansion.
-
Seismic identification and gas-bearing prediction of large-scale submarine fans of Neogene Huangliu Formation in D13 area of Yinggehai Basin
WANG Lifeng, SONG Ruiyou, CHEN Dianyuan, XU Tao, PAN Guangchao, HAN Guangming
2022, Vol.34(4): 42–52
Abstract
(
326 )
PDF (10838 KB) (
201
)
doi: https://doi.org/10.12108/yxyqc.20220405
Through the methods of sequence stratigraphy and seismic sedimentology,the large-scale submarine fans of Neogene Huangliu Formation in D13 area of Yinggehai Basin were dissected step by step,the channels in the fans were characterized and identified by multi-attribute fusion seismic slicing technology, and the gas-bearing sweet spots were predicted by the flat point reflection characteristics on seismic sections. The results show that:(1)The large-scale submarine fans in the study area were formed by the re-transportation of the paleo Lanjiang delta. Four stages of fan bodies retrograde successively were developed from southeast to northwest,and 11 stages of sand bodies can be identified. The top strata of the earlier fans were eroded by the later fans,and the sand bodies of the adjacent fans were connected vertically and locally.(2)The high-quality reservoirs in the submarine fans are mainly distributed in the submarine fan channel formed under strong sedimentary energy and high hydrodynamic force. The channel types such as bead-shaped channels,composite channels and meandering river shaped channels are developed in the fan,among which the large,thick and wide channels are the development areas of thick and high-quality sweet spot reservoirs.(3)The flat spot reflection characteristics on the seismic sections can be used to identify gas-bearing sweet spots in the channels. The flat spots in D13 area have the basic characteristics of near horizontal reflection in the channel,weakening reflection energy at the bottom of the channel, and slight inclination of the flat spot to the lower part.
-
Lithofacies types and reservoir characteristics of shales of Jurassic Da'anzhai member in central Sichuan Basin
KANG Jiahao, WANG Xingzhi, XIE Shengyang, ZENG Deming, DU Yao, ZHANG Rui, ZHANG Shaomin, LI Yang
2022, Vol.34(4): 53–65
Abstract
(
303 )
PDF (9879 KB) (
242
)
doi: https://doi.org/10.12108/yxyqc.20220406
Based on the observation of cores,thin sections,scanning electron microscope and the results of X-ray diffraction analysis and TOC content detection,the shale lithofacies of Jurassic Da'anzhai member in central Sichuan Basin was divided,and reservoir space types,physical properties and gas-bearing properties of each lithofacies were analyzed to confirm the dominant lithofacies. Combined with the vertical development characteristics of shale lithofacies and sedimentary facies,the dominant development zones were defined. The results show that:(1)The shale reservoir space of Da' anzhai member is mainly composed of clay mineral related pores and particle edge pores. The porosity ranges from 0.31% to 8.55%,with an average of 3.97%,and the permeability is 0.001-12.185 mD,with an average of 0.659 mD. The total gas content of shale is generally greater than 1.0 m3/t, and its distribution is highly consistent with porosity.(2)The shale lithofacies of Da'anzhai member in the study area can be divided into 6 categories and 13 sub-categories. Among them,shell limy clay shale lithofacies with medium-high organic carbon content has the highest organic matter abundance,brittle mineral content,porosity and gas content,which is the most dominant lithofacies,followed by silty clay shale lithofacies,clay shale lithofacies has high organic matter abundance but underdeveloped fractures,which has geological exploration potential.(3)The dominant lithofacies of Da'anzhai member in the study area is mainly distributed in the semi-deep lacustrine subfacies of Da 2 sub-member which is a favorable exploration zone.
-
Reservoir characteristics and controlling factors of the second member of Paleogene Shahejie Formation in southeastern margin of Liaodong Sag
WANG Maozhen, WU Kui, GUO Tao, HUI Guanzhou, HAO Yiwei
2022, Vol.34(4): 66–78
Abstract
(
332 )
PDF (9319 KB) (
217
)
doi: https://doi.org/10.12108/yxyqc.20220407
Sandy conglomerate is developed in the second member of Paleogene Shahejie Formation(E2s2)in the southeastern margin of Liaodong Sag. Based on the data of sidewall coring,thin section identification and element analysis,the reservoir characteristics and controlling factors of sandy conglomerate of E2s2 in southeastern margin of Liaodong Sag were analyzed from the aspects of parent rock properties,sedimentary characteristics and diagenesis. The results show that:(1)The porosity of sandy conglomerate reservoirs in the study area ranges from 3.5% to 19.0%,with an average of 10.1%,and the permeability is 0.9-120.6 mD,with an average of 39.8 mD. The overall physical properties are characterized by low porosity and low permeability,and gradually improve from north to south.(2)The sandy conglomerate with fracture developed is a high-quality reservoir in the study area,and its parent rock is metamorphic quartzite. High-quality reservoirs with high composition maturity are developed in the lower part of concordant fault slop-break zone of distal braided river delta. Argillaceous shrinkage fractures and dissolution can improve the physical properties of the reservoirs in the south section of the study area,and carbonate cementation is destructive to the physical properties of the reservoirs in the north section of the study area.(3)The concordant fault slop-break zone in gentle slope zone is conducive to the formation of inherited fracture sandy conglomerate reservoirs,and the local high parts of nearshore ancient landform are easy to form mixed beach high-quality reservoirs, both of which are potential areas for next lithologic reservoir exploration.
-
Characteristics of Permian concealed structures in western margin of Ordos Basin and its significance for oil and gas exploration
YIN Yuyi, YAO Zhichun, GUO Xiaobo, WANG Leli, CHEN Siqian, YU Xiaolei, CEN Xiangyang
2022, Vol.34(4): 79–88
Abstract
(
359 )
PDF (6892 KB) (
252
)
doi: https://doi.org/10.12108/yxyqc.20220408
Based on the actual drilling data of 3D seismic,non-seismic and wellYT2,combined with the structural evolution characteristics of Yindongzi area in the western margin of Ordos Basin and its relationship with oil and gas accumulation,the structural characteristics,oil and gas accumulation conditions and exploration prospects of thrust nappe structure in this area were studied. The results show that:(1)The structural model of Yindongzi area in the western margin of Ordos Basin is a typical forward thrust structural,moreover,the new thrust bodies were developed under the old ones,with Weizhou-Anguo fault(Wei'an fault),Qinglong Mountain- Pingliang fault(Qingping fault)and Huianpu-Shajingzi fault(Huisha fault)stretching from the west to the east accordingly.(2)There were obvious folding and deformation within the strata in the footwall of Huisha fault and Qingping fault because of the effect of nappe stress from west to east in Yanshan period,additionally,there were concealed structures developed in rows.(3)The concealed structures have obvious controlling effect on hydrocarbon accumulation in the western margin of Ordos Basin. With good source-reservoir assemblages in Permian, the concealed structures promote the development of multiple sets of sandstone reservoirs,and the development traps are relatively considerable and the preservation conditions are relatively better to some extent. Therefore,it is regarded as favorable areas for the exploration within Upper Paleozoic in the western margin of Ordos Basin.
-
Quantitative characterization of pore structure of shale reservoirs of Permian Lucaogou Formation in Jimsar Sag
ZHANG Jigang, DU Meng, CHEN Chao, QIN Ming, JIA Ninghong, LYU Weifeng, DING Zhenhua, XIANG Yong
2022, Vol.34(4): 89–102
Abstract
(
368 )
PDF (16839 KB) (
280
)
doi: https://doi.org/10.12108/yxyqc.20220409
The Permian Lucaogou Formation in Jimsar Sag is an important shale oil and gas accumulation area. Based on the analyses of cast thin sections,mercury injection and nuclear magnetic resonance,combined with medical CT,micro-CT scanning technology,quantitative evaluation of minerals by scanning electron microscope(QEMSCAN)and advanced mathematical algorithms of Avizo visualization software,a three-dimensional digital core of shale reservoirs of Lucaogou Formation in Jimsar Sag was constructed,and the pore network model parameters were extracted,and the full-scale pore size distribution curves were obtained. The comprehensively quantitative characterization of microscopic pore structure from multiple dimensions was carried out. The results show that:(1)The average porosity of the shale reservoirs of Lucaogou Formation in the study area is 7.6%, and the average permeability is 0.37 mD,which belongs to low porosity and ultra-low permeability tight shale reservoir. The main reservoir space is secondary dissolved pores,including residual intergranular pores,biological cavity pores and diagenetic microfractures.(2)The pore throat scale ranges from nanometers to micrometers. The throats within 0.12-1.75 μm have the highest contribution rate,and the submicron-micron pore throats have a greater contribution to seepage. The pores are mainly distributed in isolated and banded shape. The pore radius is mostly 4.5-12.5 μm,the throat radius is mostly 1.3-5.1 μm,and the throat length is 5-15 μm. The pore throat coordination number is mainly 1-2. The pore structure has the characteristics of strong heterogeneity and poor connectivity,and the contribution of pore connectivity to seepage is greater than that of pore scale.(3)On the nano scale,the matrix minerals are mainly quartz and albite,the main nano micropores are organic matter pores in mineral particles(crystals)and cement micropores, and the pore radius is 0.015-5.000 μm.
-
Reservoir characteristics and genesis of dolomite of Middle Permian Qixia Formation in southwestern Sichuan Basin
LI Rong, SU Chengpeng, JIA Huofu, SHI Guoshan, LIN Hui, LI Suhua
2022, Vol.34(4): 103–115
Abstract
(
305 )
PDF (13122 KB) (
236
)
doi: https://doi.org/10.12108/yxyqc.20220410
Through core observation,thin section identification,cathodoluminescence and geochemical analysis, the characteristics and genesis of dolomite of Middle Permian Qixia Formation in southwestern Sichuan Basin were studied. The results show that:(1)The matrix dolomites of Qixia Formation in the study area are mainly fine-medium crystalline dolomites,followed by powder-fine crystalline dolomites,accompanied by a small amount of coarse-grained saddle-shaped dolomites.(2)The fine-medium crystalline dolomites in the study area are consistent with the rare earth element(REE)matching model of calcite cement of granular limestone in the same period,with typical REE distribution characteristics of modern seawater,and it was formed by the replacement of granular limestone deposited in the turbulent environment of semi-restricted water body. The powder-fine crystalline dolomites have the morphological characteristics of flat REE matching with high ΣREE content,weak positive anomaly of CE and overall uplift of LREE. It was metasomatized by micritic limestone or granular marl deposited in semi-restricted water and quiet environment. The contents of Fe and Mn in different types of dolomites show a synergistic increase with the deepening of dolomitization,indicating that they have the same genesis. (3)There existed local evaporation restriction environment among the bioclastic shoals developed along the slope break zone in the study area,forming concentrated salted seawater,and penecontemporaneous reflux infiltration dolomitization resulted in the formation of powder-fine crystalline dolomites. From early diagenetic stage to shallow burial stage,the magmatic activity in the large Emei igneous province provided abnormally high heat, and the high-temperature pore water further interacted with the pre dolomite to form fine-medium crystalline dolomites,with the characteristics of fog core and bright edge. During the burial period,deep hydrothermal fluids migrated along the fractures and precipitated saddle-shaped dolomites in the fracture and surrounding rocks. The superposition of semi-restricted environment and heat source caused by bioclastic shoals is the key to the formation of dolomite in the study area.
-
Hydrocarbon generation kinetics of source rocks of Permian Fengcheng Formation in Mahu Sag,Junggar Basin
BAI Yu, WANG Fei, NIU Zhijie, JIN Kailai, LI Peiyi, XU Duonian, CHEN Gangqiang
2022, Vol.34(4): 116–127
Abstract
(
403 )
PDF (4157 KB) (
287
)
doi: https://doi.org/10.12108/yxyqc.20220411
The total proven reserves in Mahu Sag and its surrounding areas in Junggar Basin are nearly 30×108 t, and the oil mainly comes from the alkali lacustrine source rocks of Permian Fengcheng Formation in the sag. Based on thermal simulation data of gold tube experiment,combined with the calculation with Kinetic software, various hydrocarbon yields and kinetic parameters of the source rocks of Permian Fengcheng Formation in Mahu Sag were obtained,the hydrocarbon generation model was established,and then the hydrocarbon generation capacity of this set of source rocks was evaluated. The results show that:(1)The total hydrocarbon yield of alkali lacustrine source rocks of Fengcheng Formation in Mahu Sag is as high as 412.24 mg/(g·TOC),in which the liquid hydrocarbon yield first increases and then decreases with the increase of temperature,the peak temperature is between 420℃ and 460℃,the gaseous hydrocarbon yield continues to increase,the total oil production rate is higher than the gas production rate, and the carbon isotope of gaseous hydrocarbon has the characteristics of oil-formed gas.(2)The peaks of activation energy of C1, C2-C5, C6-C14 and C14+ of the source rocks of Fengcheng Formation are 268 kJ/mol, 255 kJ/mol, 251 kJ/mol and 247 kJ/mol respectively.(3)The hydrocarbon generation model of alkali lacustrine source rocks of Fengcheng Formation in Mahu Sag is similar to that of source rocks in 14 different basins at home and abroad. It has the characteristics of early oil generation peak and late continuous gas generation, and per unit TOC has upper-middle hydrocarbon generation capacity.
-
Sedimentary characteristics and source control of Lower Jurassic in coastal basins of East Africa
ZHANG Junlong, HE Youbin, LIANG Jianshe, QIU Chunguang, WU Dongsheng, LI Hua, TONG Le
2022, Vol.34(4): 128–140
Abstract
(
338 )
PDF (7671 KB) (
284
)
doi: https://doi.org/10.12108/yxyqc.20220412
The Lower Jurassic source rocks are the main source rocks in the coastal basins of East Africa. Based on the data of logging, drilling, seismic and geochemical analysis, combined with regional tectonic evolution, the sedimentary characteristics of the Lower Jurassic in the coastal basins of East Africa were analyzed and described, and the genetic model and main controlling factors of the main source rocks were characterized and evaluated by considering the characteristics of source rocks in the basins. The results show that:(1)The sedimentary environment of narrow and long occluded bay was formed by regional tectonism in the Early Jurassic in the coastal basins of East Africa,and the sedimentary systems of river,delta coastal shallow sea,confined sea or shallow sea were developed.(2)The limited marine mudstone developed in the Lower Jurassic is the high-quality source rocks of the basins,with an average TOC of 4.2%. The organic matters are mainly type Ⅰ-Ⅱ1,which has reached mature to over mature evolution stage. The mudstone is thick and widely distributed,and has great hydrocarbon generation potential. The development and distribution of main source rocks are affected by its unique sedimentary environment of bay,and the quality and hydrocarbon generation potential of main source rocks in the basins gradually improve from north to south.(3)There are three genetic models of source rocks in the coastal basins of East Africa:restricted marine sedimentary type,lagoon sedimentary type and delta sedimentary type. Among them,the restricted marine sedimentary source rock is the main genetic type of high-quality source rocks. The lithology is mainly composed of stably distributed thick mudstone and intercalated with thin sandstone,which is generally evaluated as good source rocks.(4)The most favorable hydrocarbon generating zones are located in the central areas of Rovuma Basin and Tanzania Basin on the coast of East Africa. The research results can provide reference for the next exploration and development of coastal basins in East African.
-
Water-rock interaction in deep strata under high temperature and high pressure in Pearl River Mouth Basin
LI Chengze, CHEN Guojun, TIAN Bing, YUAN Xiaoyu, SUN Rui, SU Long
2022, Vol.34(4): 141–149
Abstract
(
281 )
PDF (4989 KB) (
246
)
doi: https://doi.org/10.12108/yxyqc.20220413
Acidic fluid is the main medium of material migration and energy exchange in petroliferous basins and an important material basis for forming secondary pores and improving reservoir physical properties. Through high temperature and high pressure water-rock reaction experiment on the core samples from the Pearl River Mouth Basin, combined with the analysis and test methods of scanning electron microscope,cast thin section, reservoir physical properties,XRD and ICP-OES,the dissolution of deep clastic reservoirs and the development mechanism of secondary pores were revealed. The results show that:(1)Organic acid fluid has the effect of dissolution on rocks minerals Under high temperature and high pressure, and ion migration occurs, releasing cations such as K+,Ca2+,Na+ and Mg2+. After the reaction, the porosity of the samples was increased by 5.6% on average,and the increase was 31.5%. The content of soluble components in rocks and the primary structure of soluble minerals can affect the development of secondary pores.(2)Using representative core samples to conduct experiments of deep water-rock reaction is an effective way for reservoir evaluation in areas with less well or without well. Under the current tendency of high cost and risk for oil and gas exploration,it is a meaningful way to predict and explore resources in deep reservoir. The experiment can simulate the dissolution process and characterize the dissolution mechanism. Nowadays, under the background of high cost and high risk of deep oil and gas exploration,the experiment results have important reference value for deep reservoir prediction and exploration target optimization.
-
Oil-water flow law of Ordovician fractured-vuggy reservoirs in Tahe Oilfield
SONG Chuanzhen, MA Cuiyu
2022, Vol.34(4): 150–158
Abstract
(
310 )
PDF (4563 KB) (
296
)
doi: https://doi.org/10.12108/yxyqc.20220414
Based on the geological and production characteristics of Ordovician fractured-vuggy reservoirs in Tahe Oilfield,the conceptual fracture-vuggy model and actual geological model were established,and oil-water flow law of each model was discussed by using streamline simulation method. The results show that:(1)The fracturevuggy reservoirs in Tahe Oilfield have complex spatial structure composed of caves,pores and fractures. There are four types of caves including unfilled caves,partially-filled caves,fully filled caves and fully filled caves through with fractures. The production characteristics of different types of reservoirs differs greatly,the connectivity between wells is good,but the lateral displacement is weak.(2)The oil-water flow laws are different in different types of fractured-vuggy structure models. In unfilled caves,the fluid flowed uniformly,and the oil-water interface presented a horizontally rise under the displacement of bottom water. For the partially-filled caves,the bottom water coning in the lower filled zones was obvious,while in the upper unfilled zones,the oil-water interface tended to rise horizontally, which resulted in water sealing the remaining oil in the lower caves. In fully filled caves, the characteristics of bottom water coning are obvious,and the oil-water flow laws are similar with sandstone reservoirs. For the fully filled caves through with large-scale fractures,the fracture was a high-speed channel for oilwater flow,where water channeling happened easily. On the side of the filled cave drilled by a production well, water along the fracture was coning to the bottom of the well. However,the crude oil in the cave outside the fracture is basically undeveloped,that is the remaining oil shielded by high-angle fractures.(3)During the natural energy development process,the oil-water flow is mainly vertical and controlled by the scale of the effective reservoirs around the well,and the producing scale of single well is limited. During multi-well production,the streamline between wells is only connected below the oil-water interface and is widely distributed,and there is no or less inter-well interference. During the water-flooding development process,the streamlines between injectionproduction wells are still mainly distributed vertically. The streamline connection is better only in bottom water position. The lateral displacement of injected water is weak.
-
Reconstruction of 3D geological model of braided river sandstone reservoirs: A case study of Neogene Guantao Formation in Gaoshangpu block,Jidong Oilfield
LIU Yangping, WU Boran, YU Zhongliang, YU Chenglin, WANG Lixin, YIN Yanshu
2022, Vol.34(4): 159–170
Abstract
(
380 )
PDF (7895 KB) (
249
)
doi: https://doi.org/10.12108/yxyqc.20220415
Taking two-dimensional plane facies and profile facies of oil group Ⅳ of Neogene Guantao Formation in Gaoshangpu block of Jidong Oilfield as training images, the multi-point geostatistics probability of three-dimensional sedimentary facies was obtained by linear pooling method,the sedimentary facies types of estimated points were determined by Monte Carlo sampling, the three-dimensional fine geological model of braided river was established,and its accuracy was verified by sparse well pattern method. The results show that:(1)The main production layer in the study area is the fifth member of Guantao Formation,and sublayers 12 and 13 mainly developed channel bar,braided channel and flood plain microfacies. The channel bar is characterized by flat bottom and convex top,and the braided channel is characterized by flat top and convex bottom. The scale of channel and channel bar is small,and the general width is less than 600 m. Flood plain developed at the top of braided channel, which is characterized by sand covered by mud as a whole. The width of braided channel belts is 650-1 300 m, the average length and width of channel bar are 480 m and 176 m respectively, and the average width of braided channel is 71 m.(2)The reservoir sand body shape and spatial distribution were accurately depicted by the geological model. On the plane,the position of the channel bar is consistent with geological analysis results,and the characteristics of the thick center and thin wings of the channel bar were shown. On profile,the channel bar has the characteristics of flat bottom and convex top. In the model,the error of mudstone proportion is 9.8%,the error of channel bar proportion is 3.4%,and the error of channel proportion is 6.4%. As a whole,the modeling error is less than 10.0%.