The exploration targets in the Kuqa Depression at present are mainly structure traps in Cretaceous-Tertiary.Due to the complexity of mountain distribution and reservoir forming conditions, the exploration of Jurassic ...The exploration targets in the Kuqa Depression at present are mainly structure traps in Cretaceous-Tertiary.Due to the complexity of mountain distribution and reservoir forming conditions, the exploration of Jurassic in the eastern Kuqa Depression has been in a state of semi-stagnation since the discovery of the Yinan-2 gas reservoir.According to the concept and theory of 'continuous petroleum reservoirs' and the re-analysis of the forming conditions of the Yinan-2 gas reservoir and regional natural gas in the eastern Kuqa Depression,it is believed that the deep Jurassic has good natural gas accumulation conditions as well as geological conditions for forming continuous tight gas reservoirs.The boundary of the Yinan-2 gas reservoir is not controlled by a structural spillpoint.The downdip part of the structure is dominated by gas,while the hanging wall of the fault is filled by water and forming obvious inverted gas and water.The gas reservoir has the normal temperature and ultrahigh pressure which formed in the near source or inner-source.All of these characteristics indicate that the Yinan-2 gas reservoir is different from conventional gas reservoirs.The deep Jurassic in the eastern Kuqa Depression has multisets of source-reservoir-cap assemblages,which comprise interbedded sandstones and mudstones.These assemblages are characterized by a self-generation,self-preserving and self-coverage model.Reservoir sandstones and coal measure mudstones are interbedded with each other at a large scale.As the source rocks,Triassic-Jurassic coal measure mudstones distribute continuously at a large scale and can generate and expel hydrocarbon.Source rocks contact intimately with the overlying sandstone reservoirs.During the late stage of hydrocarbon expulsion,natural gas charged continuously and directly into the neighboring reservoirs.Petroleum migrated mainly in a vertical direction over short distances.With ultra-high pressure and strong charging intensity,natural gas accumulated continuously.Reservoirs are dominated by sandstones of braided delta facies.The sand bodies distribute continuously horizontal.With low porosity and low permeability,the reservoirs are featured by strong heterogeneity.It is hypothesized that the sandstones of the interior depression tend to be relatively tight with increasing depth and structure stress weakness.Thus,it is predicted that continuous tight gas reservoirs of ultra-high pressure may exist in the deep formations of the eastern and even the whole Kuqa Depression.So,it is worth evaluating the exploration potential.展开更多
"Continuous" tight gas reservoirs are those reservoirs which develop in widespread tight sandstones with a continuous distribution of natural gas. In this paper, we summarize the geological features of the source ro..."Continuous" tight gas reservoirs are those reservoirs which develop in widespread tight sandstones with a continuous distribution of natural gas. In this paper, we summarize the geological features of the source rocks and "'continuous" tight gas reservoirs in the Xujiahe Formation of the middle- south transition region, Sichuan Basin. The source rocks of the Xul Member and reservoir rocks of the Xu2 Member are thick (Xul Member: 40 m, Xu2 Member: 120 m) and are distributed continuously in this study area. The results of drilled wells show that the widespread sandstone reservoirs of the Xu2 Member are charged with natural gas. Therefore, the natural gas reservoirs of the Xu2 Member in the middle-south transition region are "continuous" tight gas reservoirs. The accumulation of "continuous" tight gas reservoirs is controlled by an adequate driving force of the pressure differences between source rocks and reservoirs, which is demonstrated by a "one-dimensional" physical simulation experiment. In this simulation, the natural gas of"continuous" tight gas reservoirs moves tbrward with no preferential petroleum migration pathways (PPMP), and the natural gas saturation of"continuous" tight gas reservoirs is higher than that of conventional reservoirs.展开更多
Geochronology of oil-gas accumulation (OGA) is a challenging subject of petroleum geology in multi-cycle superimposed basins.By K-Ar dating of authigenic illite (AI) and fluid inclusion (FI) analysis combined wi...Geochronology of oil-gas accumulation (OGA) is a challenging subject of petroleum geology in multi-cycle superimposed basins.By K-Ar dating of authigenic illite (AI) and fluid inclusion (FI) analysis combined with apatite fission track (AFT) thermal modeling,a case study of constraining the OGA times of the Permian reservoirs in northeast Ordos basin (NOB) has been conducted in this paper.AI dating of the Permian oil-gas-bearing sandstone core-samples shows a wide time domain of 178-108 Ma.The distribution of the AI ages presents 2-stage primary OGA processes in the Permian reservoirs,which developed in the time domains of 175-155 Ma and 145-115 Ma with 2-peak ages of 165 Ma and 130 Ma,respectively.The FI temperature peaks of the samples and their projected ages on the AFT thermal path not only present two groups with a low and a high peak temperatures in ranges of 90-78℃ and 125-118℃,respectively corresponding to 2-stage primary OGA processes of 162-153 Ma and 140-128 Ma in the Permian reservoirs,but also appear a medium temperature group with the peak of 98℃ in agreement with a secondary OGA process of c.~30 Ma in the Upper Permian reservoirs.The integrated analysis of the AI and FI ages and the tectono-thermal evolution reveals that the Permian reservoirs in the NOB experienced at least 2-stage primary OGA processes of 165-153 Ma and 140-128 Ma in agreement with the subsidence thermal process of the Mid-Early Jurassic and the tectono-thermal event of the Early Cretaceous.Then,the Upper Permian reservoirs further experienced at least 1-stage secondary OGA process of c.~30 Ma in coincidence with a critical tectonic conversion between the slow and the rapid uplift processes from the Late Cretaceous to Neogene.展开更多
Based on comprehensive analysis of tectonic and fault evolution, core, well logging, seismic, drilling, and production data, the reservoir space characteristic, distribution, origin of fault-karst carbonate reservoir ...Based on comprehensive analysis of tectonic and fault evolution, core, well logging, seismic, drilling, and production data, the reservoir space characteristic, distribution, origin of fault-karst carbonate reservoir in Yueman block of South Tahe area, Halahatang oilfield, Tarim Basin, were studied systematically. And the regular pattern of hydrocarbon accumulation and enrichment was analyzed systematically based on development practice of the reservoirs. The results show that fault-karst carbonate reservoirs are distributed in the form of "body by body" discontinuously, heterogeneously and irregularly, which are controlled by the development of faults. Three formation models of fault-karst carbonate reservoirs, namely, the models controlled by the main deep-large fault, the secondary fault and the secondary internal fault, are built. The hydrocarbon accumulation and enrichment of fault-karst carbonate reservoirs is controlled by the spatiotemporal matching relation between hydrocarbon generation period and fault activity, and the size and segmentation of fault. The study results can effectively guide the well deployment and help the efficient development of fault-karst carbonate reservoirs of South Tahe area, Halahatang oilfield.展开更多
This study presents a comparative analysis of two image enhancement techniques, Continuous Wavelet Transform (CWT) and Fast Fourier Transform (FFT), in the context of improving the clarity of high-quality 3D seismic d...This study presents a comparative analysis of two image enhancement techniques, Continuous Wavelet Transform (CWT) and Fast Fourier Transform (FFT), in the context of improving the clarity of high-quality 3D seismic data obtained from the Tano Basin in West Africa, Ghana. The research focuses on a comparative analysis of image clarity in seismic attribute analysis to facilitate the identification of reservoir features within the subsurface structures. The findings of the study indicate that CWT has a significant advantage over FFT in terms of image quality and identifying subsurface structures. The results demonstrate the superior performance of CWT in providing a better representation, making it more effective for seismic attribute analysis. The study highlights the importance of choosing the appropriate image enhancement technique based on the specific application needs and the broader context of the study. While CWT provides high-quality images and superior performance in identifying subsurface structures, the selection between these methods should be made judiciously, taking into account the objectives of the study and the characteristics of the signals being analyzed. The research provides valuable insights into the decision-making process for selecting image enhancement techniques in seismic data analysis, helping researchers and practitioners make informed choices that cater to the unique requirements of their studies. Ultimately, this study contributes to the advancement of the field of subsurface imaging and geological feature identification.展开更多
New technologies are in urgent need of unconventional hydrocarbon exploration and development in China.This paper provides a brief introduction and analysis of a new three-dimensional(3D)geomechanical restoration meth...New technologies are in urgent need of unconventional hydrocarbon exploration and development in China.This paper provides a brief introduction and analysis of a new three-dimensional(3D)geomechanical restoration method developed in recent years.After an in-depth discussion on the technical principle and specific characteristics of the fields,we designed a feasible workflow for two oil-gas fields with great unconventional oil-gas resource potentials in China(Weiyuan and Jiulongshan oil-gas fields of Sichuan).After discussing the major challenges and limitations of the new technology,we also suggest its research efforts and future application prospect It is shown that the new technology will be an effective method to facilitate the exploration and development of unconventional oil and gas resources in China.展开更多
A collection of data obtained from analytical methods in geochemistry along with the reservoir engineering and geologic data were used to investigate the reservoir continuity in the Cretaceous Fahliyan, Gadavan, Kazhd...A collection of data obtained from analytical methods in geochemistry along with the reservoir engineering and geologic data were used to investigate the reservoir continuity in the Cretaceous Fahliyan, Gadavan, Kazhdumi and Sarvak reservoirs of the super-giant Azadegan oilfield, SW Iran. The geochemical data indicate that the oil samples, with medium to high level of thermal maturity, have been generated from the anoxic marine marl/carbonate source rock(s). The Sargelu(Jurassic) and Garau(Cretaceous) formations are introduced as the main source rocks for the studied oils. The dendrogram obtained from the cluster analysis of high-resolution gas chromatography data introduces two main oil groups including Fahliyan reservoir, and Kazhdumi along with Sarvak/Gadvan reservoirs. This is confirmed by C7 Halpern star diagram, indicating that, the light oil fraction from Fahliyan reservoir is distinct from the others. Also, different pressure gradient of the Fahliyan Formation(over-pressured) relative to other reservoirs(normally-pressured) show the presence of compartments. The relation between toluene/n-heptane and n-heptane/methylcyclohexane represents the compartmentalization due to maturation/evaporative fractionation for Fahliyan and water washing for other studied reservoirs. Also, the impermeable upper part of the Fahliyan Formation and thin interbedded shaly layers in the Kazhdumi, Sarvak and Gadvan formations have controlled reservoir compartmentalization.展开更多
A total of 6 oil samples were systematically selected from six Asmari Reservoir wells in the Cheshmeh-Khush Oilfield for geochemical evaluation of the hydrocarbon system,based on reservoir geochemistry and oil fingerp...A total of 6 oil samples were systematically selected from six Asmari Reservoir wells in the Cheshmeh-Khush Oilfield for geochemical evaluation of the hydrocarbon system,based on reservoir geochemistry and oil fingerprints.An investigation of the distribution patterns of normal alkanes and tricyclic and tetracyclic terpanes along with characteristic biomarkers of the depositional environment and sedimentary facies,indicated that the source rock of the studied hydrocarbons was deposited in a reducing aquatic environment with a low input of terrigenous material and predominantly carbonate lithology derived from organic algal matter.The studied oil samples exhibited moderate maturity,as was further confirmed by the parameters extracted from the light hydrocarbons.Statistical clustering based on different biomarker parameters indicated the presence of two oil families.Additionally,the application of branched and cyclic compounds in the light hydrocarbons(C5–C11)to evaluate lateral continuity of the Asmari reservoir further supported the presence of the two oil families.Other evidence proved the presence of a NE–SW trending fault separating wells X5 and X6 from the other wells in the field.In other wells across the field,good lateral reservoir continuity was observed,despite the presence of faults on the northern and southern plunges of the structure.展开更多
The continuous rainy precipitation process from February to March in 2019 was selected to analyze the effect of meteorological service in Tangpu Reservoir basin,so as to sum up service experience and then lay a better...The continuous rainy precipitation process from February to March in 2019 was selected to analyze the effect of meteorological service in Tangpu Reservoir basin,so as to sum up service experience and then lay a better foundation for subsequent services.In response to the rainy weather from December 2018 to early 2019,three rounds of flood discharge were carried out in Tangpu Reservoir.During February-March in 2019,the hit rate of short-term area rainfall forecast for Tangpu Reservoir was 80.0%.Compared with the median of forecast interval,the average absolute error was 7.6 mm,and the relative error was 32.7%.The large deviation in the forecast from March 27 to 28 was deeply analyzed,and it is found that the main reasons were excessive reliance on and trust in a single model,insufficient correction of the actual situation,and insufficient judgment of the nature of precipitation.For the future reservoir meteorological service,three aspects of thinking were put forward,such as further strengthening the sharing of hydrological and meteorological information,improving the forecasting ability,and deepening the research of runoff forecast models.展开更多
In this paper,substantial domestic and foreign research results of microscopic shale reservoir space were systemically reviewed,the research history consisting of simple observation and qualitative classification,quan...In this paper,substantial domestic and foreign research results of microscopic shale reservoir space were systemically reviewed,the research history consisting of simple observation and qualitative classification,quantitative research,the combination of qualitative and quantitative research successively as well as the characteristics of each research stage were summarized.In addition,the current problems existing in the characterization methods of shale reservoir space were also analyzed.Furthermore,based on massive actual detection of typical core samples obtained from more than 50 global shale gas wells and relevant practical experience,a comprehensive characterization method of combining qualitative with the semiquantitative characterization was put forward.In detail,the indicators of the qualitative characterization include pore combination type and organic-matter microscopic morphology type,while the core elements of the semi-quantitative characterization include the percentage of the organic-matter area and the plane porosity of the pores of different types.Based on the reference of the naming and classification of rocks,the three-end-member diagram method was used to characterize microscopic shale reservoir space.This is achieved by plotting the three end-member diagram of 3 kinds of first-order critical reservoir spaces,i.e.,organic-matter pores,matrix pores,and micro-fractures,in order to intuitively present the features of the microscopic pore combination.Meanwhile,statistic histograms of organic-matter microscopic morphology type and the plane porosity of different types of pores were adopted to characterize the development degree of second-order pores quantitatively.By this comprehensive characterization method,the importance of both pore combination and the microscopic morphology of organic matter were emphasized,revealing the control of organic-matter microscopic morphology over the organic-matter pores.What is more,high-resolution FE-SEM was adopted to obtain semi-quantitative statistics results.In this way,the features of pore development and pore combination were quantified,not only reflecting the types and storage capacity of the microscopic shale reservoir space,but also presenting the hydrocarbongenerating potential of organic matter in shale.Therefore,the results of this research are capable of providing in-depth microscopic information for the assessment and exploration and development of shale gas resources.展开更多
The Lower Cretaceous Yingcheng Formation in the southern Songliao Basin is the typical tight oil sandstone in China.In order to better predict the petrophysical properties of the tight sandstone reservoirs in the Lowe...The Lower Cretaceous Yingcheng Formation in the southern Songliao Basin is the typical tight oil sandstone in China.In order to better predict the petrophysical properties of the tight sandstone reservoirs in the Lower Cretaceous Yingcheng Formation,Songliao Basin,Northeast China,the diagenesis and porosity evolution was investigated using a suite of petrographic and geochemical techniques including thin section analysis,scanning electron microscopy,mercury intrusion and fluid inclusion analysis,on a set of selected tight sandstone samples.Combined with the histories of burial evolution,organic matter thermal evolution and hydrocarbon charge,the matching relationship between reservoir porosity evolution and hydrocarbon accumulation history is analyzed.The result showed that the tight sandstone reservoirs characterized of being controlled by deposition,predominated by compaction,improved by dissolution and enhanced by cementation.The hydrocarbon accumulation period was investigated using a suite of hydrocarbon generation and expulsion history,microfluorescence determination and temperature measurement technology.According to the homogenization temperature of the inclusions and the history of burial evolution,Yingcheng Formation has mainly two phases hydrocarbon accumulation.The first phase of oil and gas is charged before the reservoir is tightened,the oil and gas generated by Shahezi source rocks enter the sand body of Yingcheng Formation,influenced by the carrying capability of sand conducting layer,oil and gas is mainly conducted by the better properties and higher connectivity sand body and enriched in the east,which belongs to the type of densification after hydrocarbon accumulation.The second phase of oil and gas charge after densification,which belongs to the type of densification before the hydrocarbon accumulation.展开更多
The Ordos Basin is the largest continental multi-energy mineral basin in China,which is rich in coal,oil and gas,and uranium resources.The exploitation of mineral resources is closely related to reservoir water.The ch...The Ordos Basin is the largest continental multi-energy mineral basin in China,which is rich in coal,oil and gas,and uranium resources.The exploitation of mineral resources is closely related to reservoir water.The chemical properties of reservoir water are very important for reservoir evaluation and are significant indicators of the sealing of reservoir oil and gas resources.Therefore,the caprock of the Chang 6 reservoir in the Yanchang Formation was evaluated.The authors tested and analyzed the chemical characteristics of water samples selected from 30 wells in the Chang 6 reservoir of Ansai Oilfield in the Ordos Basin.The results show that the Chang 6 reservoir water in Ansai Oilfield is dominated by calcium-chloride water type with a sodium chloride coefficient of generally less than 0.5.The chloride magnesium coefficients are between 33.7 and 925.5,most of which are greater than 200.The desulfurization coefficients range from 0.21 to 13.4,with an average of 2.227.The carbonate balance coefficients are mainly concentrated below 0.01,with an average of 0.008.The calcium and magnesium coefficients are between 0.08 and 0.003,with an average of 0.01.Combined with the characteristics of the four-corner layout of the reservoir water,the above results show that the graphics are basically consistent.The study indicates that the Chang 6 reservoir in Ansai Oilfield in the Ordos Basin is a favorable block for oil and gas storage with good sealing properties,great preservation conditions of oil and gas,and high pore connectivity.展开更多
基金funded by the National Science and technology Major Project(2008ZX05001)
文摘The exploration targets in the Kuqa Depression at present are mainly structure traps in Cretaceous-Tertiary.Due to the complexity of mountain distribution and reservoir forming conditions, the exploration of Jurassic in the eastern Kuqa Depression has been in a state of semi-stagnation since the discovery of the Yinan-2 gas reservoir.According to the concept and theory of 'continuous petroleum reservoirs' and the re-analysis of the forming conditions of the Yinan-2 gas reservoir and regional natural gas in the eastern Kuqa Depression,it is believed that the deep Jurassic has good natural gas accumulation conditions as well as geological conditions for forming continuous tight gas reservoirs.The boundary of the Yinan-2 gas reservoir is not controlled by a structural spillpoint.The downdip part of the structure is dominated by gas,while the hanging wall of the fault is filled by water and forming obvious inverted gas and water.The gas reservoir has the normal temperature and ultrahigh pressure which formed in the near source or inner-source.All of these characteristics indicate that the Yinan-2 gas reservoir is different from conventional gas reservoirs.The deep Jurassic in the eastern Kuqa Depression has multisets of source-reservoir-cap assemblages,which comprise interbedded sandstones and mudstones.These assemblages are characterized by a self-generation,self-preserving and self-coverage model.Reservoir sandstones and coal measure mudstones are interbedded with each other at a large scale.As the source rocks,Triassic-Jurassic coal measure mudstones distribute continuously at a large scale and can generate and expel hydrocarbon.Source rocks contact intimately with the overlying sandstone reservoirs.During the late stage of hydrocarbon expulsion,natural gas charged continuously and directly into the neighboring reservoirs.Petroleum migrated mainly in a vertical direction over short distances.With ultra-high pressure and strong charging intensity,natural gas accumulated continuously.Reservoirs are dominated by sandstones of braided delta facies.The sand bodies distribute continuously horizontal.With low porosity and low permeability,the reservoirs are featured by strong heterogeneity.It is hypothesized that the sandstones of the interior depression tend to be relatively tight with increasing depth and structure stress weakness.Thus,it is predicted that continuous tight gas reservoirs of ultra-high pressure may exist in the deep formations of the eastern and even the whole Kuqa Depression.So,it is worth evaluating the exploration potential.
基金supported by the National Major Grant of"Accumulation Law,Key Technologies and Evaluations of the Stratigraphic Reservoirs"(No.2008ZX05000-001) from the Research Institute of Petroleum Exploration & Development,PetroChina
文摘"Continuous" tight gas reservoirs are those reservoirs which develop in widespread tight sandstones with a continuous distribution of natural gas. In this paper, we summarize the geological features of the source rocks and "'continuous" tight gas reservoirs in the Xujiahe Formation of the middle- south transition region, Sichuan Basin. The source rocks of the Xul Member and reservoir rocks of the Xu2 Member are thick (Xul Member: 40 m, Xu2 Member: 120 m) and are distributed continuously in this study area. The results of drilled wells show that the widespread sandstone reservoirs of the Xu2 Member are charged with natural gas. Therefore, the natural gas reservoirs of the Xu2 Member in the middle-south transition region are "continuous" tight gas reservoirs. The accumulation of "continuous" tight gas reservoirs is controlled by an adequate driving force of the pressure differences between source rocks and reservoirs, which is demonstrated by a "one-dimensional" physical simulation experiment. In this simulation, the natural gas of"continuous" tight gas reservoirs moves tbrward with no preferential petroleum migration pathways (PPMP), and the natural gas saturation of"continuous" tight gas reservoirs is higher than that of conventional reservoirs.
基金supported by the National Basic Research Program of China (No.2003CB2146007)the Special Research Fund for the Doctoral Program of Colleges and Universities of the National Education Ministry of China (No. 20116101110006)+2 种基金the Key Project of Natural Science Basic Research Plan in Shaanxi Province of China (No.2012JZ5001)the Oil-gas Survey Project of China Geological Survey Bureau (1212011220761)the Preferred Foundation of Study Abroad Returnees of the Human Resources and Social Security of China
文摘Geochronology of oil-gas accumulation (OGA) is a challenging subject of petroleum geology in multi-cycle superimposed basins.By K-Ar dating of authigenic illite (AI) and fluid inclusion (FI) analysis combined with apatite fission track (AFT) thermal modeling,a case study of constraining the OGA times of the Permian reservoirs in northeast Ordos basin (NOB) has been conducted in this paper.AI dating of the Permian oil-gas-bearing sandstone core-samples shows a wide time domain of 178-108 Ma.The distribution of the AI ages presents 2-stage primary OGA processes in the Permian reservoirs,which developed in the time domains of 175-155 Ma and 145-115 Ma with 2-peak ages of 165 Ma and 130 Ma,respectively.The FI temperature peaks of the samples and their projected ages on the AFT thermal path not only present two groups with a low and a high peak temperatures in ranges of 90-78℃ and 125-118℃,respectively corresponding to 2-stage primary OGA processes of 162-153 Ma and 140-128 Ma in the Permian reservoirs,but also appear a medium temperature group with the peak of 98℃ in agreement with a secondary OGA process of c.~30 Ma in the Upper Permian reservoirs.The integrated analysis of the AI and FI ages and the tectono-thermal evolution reveals that the Permian reservoirs in the NOB experienced at least 2-stage primary OGA processes of 165-153 Ma and 140-128 Ma in agreement with the subsidence thermal process of the Mid-Early Jurassic and the tectono-thermal event of the Early Cretaceous.Then,the Upper Permian reservoirs further experienced at least 1-stage secondary OGA process of c.~30 Ma in coincidence with a critical tectonic conversion between the slow and the rapid uplift processes from the Late Cretaceous to Neogene.
基金Supported by the China National Sicence and Technology Project(2016ZX05004)
文摘Based on comprehensive analysis of tectonic and fault evolution, core, well logging, seismic, drilling, and production data, the reservoir space characteristic, distribution, origin of fault-karst carbonate reservoir in Yueman block of South Tahe area, Halahatang oilfield, Tarim Basin, were studied systematically. And the regular pattern of hydrocarbon accumulation and enrichment was analyzed systematically based on development practice of the reservoirs. The results show that fault-karst carbonate reservoirs are distributed in the form of "body by body" discontinuously, heterogeneously and irregularly, which are controlled by the development of faults. Three formation models of fault-karst carbonate reservoirs, namely, the models controlled by the main deep-large fault, the secondary fault and the secondary internal fault, are built. The hydrocarbon accumulation and enrichment of fault-karst carbonate reservoirs is controlled by the spatiotemporal matching relation between hydrocarbon generation period and fault activity, and the size and segmentation of fault. The study results can effectively guide the well deployment and help the efficient development of fault-karst carbonate reservoirs of South Tahe area, Halahatang oilfield.
文摘This study presents a comparative analysis of two image enhancement techniques, Continuous Wavelet Transform (CWT) and Fast Fourier Transform (FFT), in the context of improving the clarity of high-quality 3D seismic data obtained from the Tano Basin in West Africa, Ghana. The research focuses on a comparative analysis of image clarity in seismic attribute analysis to facilitate the identification of reservoir features within the subsurface structures. The findings of the study indicate that CWT has a significant advantage over FFT in terms of image quality and identifying subsurface structures. The results demonstrate the superior performance of CWT in providing a better representation, making it more effective for seismic attribute analysis. The study highlights the importance of choosing the appropriate image enhancement technique based on the specific application needs and the broader context of the study. While CWT provides high-quality images and superior performance in identifying subsurface structures, the selection between these methods should be made judiciously, taking into account the objectives of the study and the characteristics of the signals being analyzed. The research provides valuable insights into the decision-making process for selecting image enhancement techniques in seismic data analysis, helping researchers and practitioners make informed choices that cater to the unique requirements of their studies. Ultimately, this study contributes to the advancement of the field of subsurface imaging and geological feature identification.
文摘New technologies are in urgent need of unconventional hydrocarbon exploration and development in China.This paper provides a brief introduction and analysis of a new three-dimensional(3D)geomechanical restoration method developed in recent years.After an in-depth discussion on the technical principle and specific characteristics of the fields,we designed a feasible workflow for two oil-gas fields with great unconventional oil-gas resource potentials in China(Weiyuan and Jiulongshan oil-gas fields of Sichuan).After discussing the major challenges and limitations of the new technology,we also suggest its research efforts and future application prospect It is shown that the new technology will be an effective method to facilitate the exploration and development of unconventional oil and gas resources in China.
基金National Iranian Oil Company-Exploration Directorate(NIOC-EXP)the Petroleum Geology and Geochemistry Research Center(PGGRC)of Shahid Chamran University of Ahvaz.
文摘A collection of data obtained from analytical methods in geochemistry along with the reservoir engineering and geologic data were used to investigate the reservoir continuity in the Cretaceous Fahliyan, Gadavan, Kazhdumi and Sarvak reservoirs of the super-giant Azadegan oilfield, SW Iran. The geochemical data indicate that the oil samples, with medium to high level of thermal maturity, have been generated from the anoxic marine marl/carbonate source rock(s). The Sargelu(Jurassic) and Garau(Cretaceous) formations are introduced as the main source rocks for the studied oils. The dendrogram obtained from the cluster analysis of high-resolution gas chromatography data introduces two main oil groups including Fahliyan reservoir, and Kazhdumi along with Sarvak/Gadvan reservoirs. This is confirmed by C7 Halpern star diagram, indicating that, the light oil fraction from Fahliyan reservoir is distinct from the others. Also, different pressure gradient of the Fahliyan Formation(over-pressured) relative to other reservoirs(normally-pressured) show the presence of compartments. The relation between toluene/n-heptane and n-heptane/methylcyclohexane represents the compartmentalization due to maturation/evaporative fractionation for Fahliyan and water washing for other studied reservoirs. Also, the impermeable upper part of the Fahliyan Formation and thin interbedded shaly layers in the Kazhdumi, Sarvak and Gadvan formations have controlled reservoir compartmentalization.
基金the Exploration Directorate of the National Iranian Oil Company for providing the research team with the required funding for performing the analysis utilized in this project。
文摘A total of 6 oil samples were systematically selected from six Asmari Reservoir wells in the Cheshmeh-Khush Oilfield for geochemical evaluation of the hydrocarbon system,based on reservoir geochemistry and oil fingerprints.An investigation of the distribution patterns of normal alkanes and tricyclic and tetracyclic terpanes along with characteristic biomarkers of the depositional environment and sedimentary facies,indicated that the source rock of the studied hydrocarbons was deposited in a reducing aquatic environment with a low input of terrigenous material and predominantly carbonate lithology derived from organic algal matter.The studied oil samples exhibited moderate maturity,as was further confirmed by the parameters extracted from the light hydrocarbons.Statistical clustering based on different biomarker parameters indicated the presence of two oil families.Additionally,the application of branched and cyclic compounds in the light hydrocarbons(C5–C11)to evaluate lateral continuity of the Asmari reservoir further supported the presence of the two oil families.Other evidence proved the presence of a NE–SW trending fault separating wells X5 and X6 from the other wells in the field.In other wells across the field,good lateral reservoir continuity was observed,despite the presence of faults on the northern and southern plunges of the structure.
文摘The continuous rainy precipitation process from February to March in 2019 was selected to analyze the effect of meteorological service in Tangpu Reservoir basin,so as to sum up service experience and then lay a better foundation for subsequent services.In response to the rainy weather from December 2018 to early 2019,three rounds of flood discharge were carried out in Tangpu Reservoir.During February-March in 2019,the hit rate of short-term area rainfall forecast for Tangpu Reservoir was 80.0%.Compared with the median of forecast interval,the average absolute error was 7.6 mm,and the relative error was 32.7%.The large deviation in the forecast from March 27 to 28 was deeply analyzed,and it is found that the main reasons were excessive reliance on and trust in a single model,insufficient correction of the actual situation,and insufficient judgment of the nature of precipitation.For the future reservoir meteorological service,three aspects of thinking were put forward,such as further strengthening the sharing of hydrological and meteorological information,improving the forecasting ability,and deepening the research of runoff forecast models.
基金This study was supported by the National Scientific and Technological Major Special Project titled“Research on Evaluation Method and Exploration Technology on Shale Gas Resources”(2016ZX05034)“Shale Gas Basic Geological Survey Project in South China”(121201229000160021)initiated by CGSinter-governmental cooperation project titled“China-USA Cooperation Research Project of Carboniferous-Permian Shale Reservoir Evaluation Technology”(2017YFE0106300).
文摘In this paper,substantial domestic and foreign research results of microscopic shale reservoir space were systemically reviewed,the research history consisting of simple observation and qualitative classification,quantitative research,the combination of qualitative and quantitative research successively as well as the characteristics of each research stage were summarized.In addition,the current problems existing in the characterization methods of shale reservoir space were also analyzed.Furthermore,based on massive actual detection of typical core samples obtained from more than 50 global shale gas wells and relevant practical experience,a comprehensive characterization method of combining qualitative with the semiquantitative characterization was put forward.In detail,the indicators of the qualitative characterization include pore combination type and organic-matter microscopic morphology type,while the core elements of the semi-quantitative characterization include the percentage of the organic-matter area and the plane porosity of the pores of different types.Based on the reference of the naming and classification of rocks,the three-end-member diagram method was used to characterize microscopic shale reservoir space.This is achieved by plotting the three end-member diagram of 3 kinds of first-order critical reservoir spaces,i.e.,organic-matter pores,matrix pores,and micro-fractures,in order to intuitively present the features of the microscopic pore combination.Meanwhile,statistic histograms of organic-matter microscopic morphology type and the plane porosity of different types of pores were adopted to characterize the development degree of second-order pores quantitatively.By this comprehensive characterization method,the importance of both pore combination and the microscopic morphology of organic matter were emphasized,revealing the control of organic-matter microscopic morphology over the organic-matter pores.What is more,high-resolution FE-SEM was adopted to obtain semi-quantitative statistics results.In this way,the features of pore development and pore combination were quantified,not only reflecting the types and storage capacity of the microscopic shale reservoir space,but also presenting the hydrocarbongenerating potential of organic matter in shale.Therefore,the results of this research are capable of providing in-depth microscopic information for the assessment and exploration and development of shale gas resources.
基金The authors acknowledge sponsorship from China Petroleum Science and Technology Innovation Fund(2017d-5007-0101)China Geological Survey project(DD20191007)Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(GML2019ZD0207).
文摘The Lower Cretaceous Yingcheng Formation in the southern Songliao Basin is the typical tight oil sandstone in China.In order to better predict the petrophysical properties of the tight sandstone reservoirs in the Lower Cretaceous Yingcheng Formation,Songliao Basin,Northeast China,the diagenesis and porosity evolution was investigated using a suite of petrographic and geochemical techniques including thin section analysis,scanning electron microscopy,mercury intrusion and fluid inclusion analysis,on a set of selected tight sandstone samples.Combined with the histories of burial evolution,organic matter thermal evolution and hydrocarbon charge,the matching relationship between reservoir porosity evolution and hydrocarbon accumulation history is analyzed.The result showed that the tight sandstone reservoirs characterized of being controlled by deposition,predominated by compaction,improved by dissolution and enhanced by cementation.The hydrocarbon accumulation period was investigated using a suite of hydrocarbon generation and expulsion history,microfluorescence determination and temperature measurement technology.According to the homogenization temperature of the inclusions and the history of burial evolution,Yingcheng Formation has mainly two phases hydrocarbon accumulation.The first phase of oil and gas is charged before the reservoir is tightened,the oil and gas generated by Shahezi source rocks enter the sand body of Yingcheng Formation,influenced by the carrying capability of sand conducting layer,oil and gas is mainly conducted by the better properties and higher connectivity sand body and enriched in the east,which belongs to the type of densification after hydrocarbon accumulation.The second phase of oil and gas charge after densification,which belongs to the type of densification before the hydrocarbon accumulation.
基金supported by the Jiangsu Natural Science Foundation project(SBK2021045820)the Chongqing Natural Science Foundation general Project(cstc2021jcyj-msxmX0624)+1 种基金the Graduate Innovation Program of China University of Mining and Technology(2022WLKXJ002)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX22_2600).
文摘The Ordos Basin is the largest continental multi-energy mineral basin in China,which is rich in coal,oil and gas,and uranium resources.The exploitation of mineral resources is closely related to reservoir water.The chemical properties of reservoir water are very important for reservoir evaluation and are significant indicators of the sealing of reservoir oil and gas resources.Therefore,the caprock of the Chang 6 reservoir in the Yanchang Formation was evaluated.The authors tested and analyzed the chemical characteristics of water samples selected from 30 wells in the Chang 6 reservoir of Ansai Oilfield in the Ordos Basin.The results show that the Chang 6 reservoir water in Ansai Oilfield is dominated by calcium-chloride water type with a sodium chloride coefficient of generally less than 0.5.The chloride magnesium coefficients are between 33.7 and 925.5,most of which are greater than 200.The desulfurization coefficients range from 0.21 to 13.4,with an average of 2.227.The carbonate balance coefficients are mainly concentrated below 0.01,with an average of 0.008.The calcium and magnesium coefficients are between 0.08 and 0.003,with an average of 0.01.Combined with the characteristics of the four-corner layout of the reservoir water,the above results show that the graphics are basically consistent.The study indicates that the Chang 6 reservoir in Ansai Oilfield in the Ordos Basin is a favorable block for oil and gas storage with good sealing properties,great preservation conditions of oil and gas,and high pore connectivity.