The Lenghu area is one of the most crucial tectonic belts for oil and gas exploration in the Qaidam Basin.However,reservoir distribution and the factors controlling petroleum accumulation in this area have not been st...The Lenghu area is one of the most crucial tectonic belts for oil and gas exploration in the Qaidam Basin.However,reservoir distribution and the factors controlling petroleum accumulation in this area have not been studied in detail.In this paper,the structural characteristics and controlling factors of oil and gas accumulation in the Lenghu belt are investigated based on seismic profiles combined with drilling logs and microphotographs data.Results indicate that the Lenghu belt has thick source rocks and has preserved hydrocarbon generation conditions.Moreover,structural characteristics and lithology are the key factors controlling the reservoir distribution.The production of oil and gas layers are mainly distributed in high structural points and weak stress zones.The fracture zones and the weak stress zones are the potential places for the distribution of oil and gas reservoirs.展开更多
Based on the previous studies and development practice in recent 10 years, a quantitative evaluation method for the adaptability of well patterns to ultra-low permeability reservoirs was established using cluster anal...Based on the previous studies and development practice in recent 10 years, a quantitative evaluation method for the adaptability of well patterns to ultra-low permeability reservoirs was established using cluster analysis and gray correlation method, and it includes 10 evaluation parameters in the four aspects of optimal evaluation parameters, determination of weights for evaluation parameters, development stage division, and determination of classification coefficients. This evaluation method was used to evaluate the well pattern adaptability of 13 main ultra-low permeability reservoirs in Triassic Chang 6 and Chang 8 of Ordos Basin. Three basic understandings were obtained: Firstly, the well pattern for ultra-low permeability type-I reservoirs has generally good adaptability, with proper well pattern forms and well pattern parameters. Secondly, square inverted nine-spot well pattern is suitable for reservoirs with no fractures; rhombic inverted nine-spot injection pattern is suitable for reservoirs with some fractures; and rectangular well pattern is suitable for reservoirs with rich fractures. Thirdly, for the ultra-low permeability type-Ⅱ and type-Ⅲ reservoirs, with the principles of well pattern form determination, the row spacing needs to be optimized further to improve the level of development of such reservoirs.展开更多
1 Introduction Reservoir architecture analysis of distributary channel of Daqing oilfield has drawn consistent interest among development geologists and petroleum engineers over the last decade(Lv et al.,1999;Zhou et ...1 Introduction Reservoir architecture analysis of distributary channel of Daqing oilfield has drawn consistent interest among development geologists and petroleum engineers over the last decade(Lv et al.,1999;Zhou et al.,2008;Zhang et展开更多
In this paper, first, based on landscape ecology theories, we respectively selected indexes from 4 aspects, area, edge, shape, and density, of the landscape type to describe the status of forest landscape patterns, an...In this paper, first, based on landscape ecology theories, we respectively selected indexes from 4 aspects, area, edge, shape, and density, of the landscape type to describe the status of forest landscape patterns, and we established the stability index of landscape pattern (LSBI). Then, based on geo-statistical theories, we divided the forest in the reservoir area into 3990 grids of 4 km × 4 km using network technology and employing ordinary Kriging modelling to make trend surface analyses of the forest resources in the reservoir area. Finally, based on statistics principles, we used sampling theory to systematically extract 227 samples to obtain 7 periods of remote-sensing data from 1990a to 2012a. Then, we classified and extracted the forest in the sampling area using remote sensing, and we analysed each result with an Autoregressive Integrated Moving Average Model (ARIMA) time-series model. The results indicated the following: 1) the landscape structure of the reservoir area was primarily needle-leaved forest, broad-leaved forest and bush forest, and the mixed stands and bamboo stands were secondary;2) the difference of the forest landscape pattern stability in the reservoir area, in all directions, was not significant, but the southern region was slightly more stable;and 3) the stability of the forest landscape pattern in the reservoir area increased from 1990a to 2012a. It kept increasing until 2016a. This study provides a theoretical basis for the reasonable management and decisions about the forest resources in the Three Gorges Reservoir Area. Meanwhile, it also explores methods for relevant research and has practical significance.展开更多
This paper studied the distribution and utilization status, reasonable exploitation patterns and potential productivity, and sustainable development of marginal lands in the Three Gorge Reservoir Areas. It has been po...This paper studied the distribution and utilization status, reasonable exploitation patterns and potential productivity, and sustainable development of marginal lands in the Three Gorge Reservoir Areas. It has been pointed that problems of the soil fertility degradation, poor productivity in crop lands, natural disasters and environmental deterioration existed in all the exploited marginal lands. In order to maintain the sustainability of the marginal lands, following measure have been proposed: prohibiting cultivation in the crop lands with a slope more than 25°, restoring vegetation in the slope more than 25°, strengthening the basic agricultural construction, establishing the production base of woody feeds and oils, establishing a multi dimensional management model with reasonable structure and optimum function for forestry, agriculture and fishing.展开更多
In this study,taking the typical terracing land in Wushan County of Chongqing Municipality for example,we study the distribution of soil nutrients in the terracing land under different land use patterns in Three Gorge...In this study,taking the typical terracing land in Wushan County of Chongqing Municipality for example,we study the distribution of soil nutrients in the terracing land under different land use patterns in Three Gorges Reservoir Area. We conduct field survey and sampling on three different land use patterns( cash crop land,food crop land and abandoned land),and do the indoor experimental analysis of soil nutrient indicators. The results indicate that there is significant or very significant impact on soil nutrients under different land use patterns. The content of soil organic matter declines in sequence from abandoned land,food crop land to cash crop land; the content of soil N declines in sequence from cash crop land,abandoned land to food crop land; the content of soil P declines in sequence from cash crop land,food crop land to abandoned land; the content of soil K declines in sequence from abandoned land,cash crop land to food crop land. The result is in close relation to land use patterns,human cultivation activity,land disturbance and application of fertilizer.展开更多
Coal-measure gas is a primary target with significant potential for the exploration of unconventional hydrocarbon resources.However,the spatiotemporal distribution and combination patterns of multi-type coal-measure g...Coal-measure gas is a primary target with significant potential for the exploration of unconventional hydrocarbon resources.However,the spatiotemporal distribution and combination patterns of multi-type coal-measure gases are yet to be clarified,directly impeding the sweet spot evaluation and exploration deployment of coal-measure gas.This study discussed the characteristics and distribution patterns of coal-measure gases in the Daniudi gas field in northeastern Ordos Basin,China,with abundant drilling data.The results indicate that the coal seams variably thin upward and are mainly seen in the first and second members of the Taiyuan Formation(also referred to as the Tai 1 and Tai 2 members,respectively)and the first member of the Shanxi Formation(Shan 1 Member).Nos.8,5 and 3 coal seams are laterally continuous,and significantly thicker in its southern part compared to the northern part.Moreover,carbonaceous mudstones and shales are better developed in the southern part,where limestones are only observed in the Tai 1 Member.Based on the main lithological types,we identified three lithologic roofs of coal seams,that is,limestone,mudstone,and sandstone,which determine the spatiotemporal distribution of coal-measure gases.Besides bauxite gas in the Benxi Formation,the coal-measure gases include tight-sand gas,coalbed methane(CBM),coal-measure shale gas,and tight-limestone gas,with CBM typically associated with coal-measure shale gas.The combinations of different types of coal-measure gas vary across different layers and regions.Tight-sand gas is well-developed in areas where tight sandstones are in contact with coal-measures.From the Taiyuan to the Shanxi formations,CBM gradually transitions into a combination of CBM and coal-measure shale gas,and coal-measure shale gas.Nos.8 and 5 coal seams in low-lying areas exhibit favorable gas-bearing properties due to their large thickness and favorable roof lithologies,serving as prospective play fairways.Mudstone and limestone roofs are more conducive to achieving good gas-bearing properties.The direct contact between sandstones and coal seams tends to result in the formation of tight-sand gas and a reduced gas content of CBM.While focusing on single types of gas reservoirs such as CBM and tight-sand gas,it is essential to consider the concurrent exploration of various coal-measure gas combinations to discover more additional gas resources and guide exploration deployment.展开更多
Based on the similarity criterion, volcanic rock samples were taken from outcrops to make experimental models. Water flooding experiments of five-spot well pattern, nine-spot well pattern, five-spot to nine-spot well ...Based on the similarity criterion, volcanic rock samples were taken from outcrops to make experimental models. Water flooding experiments of five-spot well pattern, nine-spot well pattern, five-spot to nine-spot well pattern, the relationship between relative well and fracture positions, and injection rate in dissolution vug-cave reservoirs with/without fractures were carried out to analyze variation regularities of development indexes, find out development characteristics of water flooding with different well patterns and sort out the optimal water flooding development mode. For dissolution vug-cave reservoirs without fractures, five-spot well pattern waterflooding has very small sweeping area, serious water channeling and low oil recovery. When the well pattern was adjusted from five-spot to nine-spot well pattern, oil recovery could be largely improved, but the corner well far from the injector is little affected. In dissolution vug-cave reservoirs with fractures, when the injector and producer are not connected by fractures, the fractures could effectively connect the poorly linked vugs to improve the development effect of water flooding. Whether there are fractures or not in dissolution vug-cave reservoirs, the development effect of nine-spot well-pattern is much better than that of five-spot well pattern and five-spot to nine-spot well pattern, this is more evident when there are fractures, and the edge well has better development indexes than corner well. At the high-water cut stage of water flooding with nine-spot well pattern, the oil recovery can be further improved with staggered line-drive pattern by converting the corner well into injection well. It is helpful to increase the oil production of corner well of nine-spot well pattern by increasing the injection rate, and improve ultimate oil recovery, but the water-free production period would be greatly shortened and water-free recovery would decrease.展开更多
For thin oil rim reservoir with gas cap and edge water, it is helpful to improve the development effect to find out the distribution law of remaining oil in this kind of reservoirs. For this reason, taking the narrow ...For thin oil rim reservoir with gas cap and edge water, it is helpful to improve the development effect to find out the distribution law of remaining oil in this kind of reservoirs. For this reason, taking the narrow oil rim reservoir with gas cap and edge water of Oilfield A in Bohai Sea as a case, the main controlling factors, including reservoir structure, fault, gas cap energy, edge water energy and well pattern, affecting the distribution of residual oil in this kind of reservoir were analyzed by using the data of core, logging, paleogeomorphology and production. Then, the distribution law of remaining oil was summarized. Generally, the remaining oil distribution is mainly potato-shaped or strip-shaped in plane. Vertically, it depends on the energy of gas cap and edge water. For the reservoir with big gas gap and weak edge water, the remaining oil mainly lies in the bottom of oil column. And for the reservoir with small gas gap and strong edge water, the remaining oil mainly locates at the top of oil column. Aiming at different distribution modes of remaining oil, the corresponding potential tapping strategies of horizontal wells are put forward: in the late stage of development, for the reservoir with big gas gap and weak edge water, the remaining oil concentrates at the bottom of the oil column, and the position of horizontal well should be placed at the lower 1/3 to the lower 1/5 of the oil column;for the reservoir with small gas cap and strong edge water, the remaining oil locates at the top of the oil column, and the position of horizontal well should be put at the upper 1/5 to the upper 1/3 of the oil column height, vertically. Based on the study on remaining oil of Oilfield A, a potential tapping strategy of well pattern thickening and vertical position optimization of horizontal well was proposed. This strategy guided the efficient implementation of the comprehensive adjustment plan of the oilfield. Moreover, 18 infill development wells were implemented in Oilfield A, and the average production of the infill wells is 2.1 times that of the surrounding old wells. It is estimated that the ultimate recovery factor of the oilfield will reach 33.9%, which is 2.3% higher than that before infilling wells. This study can be used for reference in the development of similar reservoirs.展开更多
Carbonate reservoir patterns play an important role in the production performance of oil and gas wells,and it is usually classified through static data analysis which cannot reflect the actual well performance.This pa...Carbonate reservoir patterns play an important role in the production performance of oil and gas wells,and it is usually classified through static data analysis which cannot reflect the actual well performance.This paper takes the Tazhong No.1 gas field in the Tarim Basin,China as an example to investigate the classification of carbonate reservoirs.The classification method mainly combines well test analysis with production analysis—especially the Blasingame type curve method.Based on the characteristics of type curves for well test analysis and the Blasingame method,the relationship between the type curves and reservoir pattern was established.More than 20 wells were analyzed and the reservoirs were classified into 3 major patterns with 7 sub-classes.Furthermore,the classification results were validated by dynamic performance analysis of wells in the Tazhong No.1 gas field.On the basis of the classification results,well stimulation（i.e.water flooding in a single well） was carried out in three volatile-oil wells,and the oil recovery increased by up to 20%.展开更多
By using TM remote sensing images of Baiyangdian Wetland in 1989,1999,2003 and 2004,taking the water area between Anxin County and Cangzhou where most of Baiyangdian Wetland water body lies for landscape classificatio...By using TM remote sensing images of Baiyangdian Wetland in 1989,1999,2003 and 2004,taking the water area between Anxin County and Cangzhou where most of Baiyangdian Wetland water body lies for landscape classification,changes in landscape pattern of Baiyangdian before and after the water supplement were analyzed with landscape indexes calculated by Fragstats3.3. The results showed that after the water supplement,from the perspective of landscape cell index,fractal dimension of major ecosystems in Baiyangdian decreased to some extent;from the perspective of landscape diversity index,diversity index of the study region also decreased,which demonstrated that ecosystem diversity in this region reduced,land cover grew to simplification;and the decreasing evenness degree of the study region also showed the uneven development of its ecosystems. That is to say,water supplement has brought favorable ecological changes to the eco-environment of Baiyangdian,which has further optimized the health condition of ecosystems in this region.展开更多
The genesis of the Ordovician karst in the Tahe Oilfield is hypothesized on the basis of many analyses of the geo-chemical data and the sporopollen. Ordovician carbonate rocks experienced multistage karst reconstructi...The genesis of the Ordovician karst in the Tahe Oilfield is hypothesized on the basis of many analyses of the geo-chemical data and the sporopollen. Ordovician carbonate rocks experienced multistage karst reconstructions under the condition of low-temperature oxidation meteoric water on the surface or near-surface. The karst occurred mainly in the early Hercynian, which has undergone three stages of karst cycle and developed three sets of cave reservoirs under the influence of the tectonic uplift, and the upper of the cave was formed earlier. The evidence of karst was found in the Caledonian. On the above basis, the genetic prediction pattern of the Ordovician palaeokarst reservoir in this region was set up.展开更多
基金supported by the State Key Laboratory of Petroleum Resource and Prospecting,China University of Petroleum,Beijing(No.PRP/Open-1903)the Talents of Guizhou,China(Qian Ke He Platform and Talent(No.2017)5727-04)+1 种基金the Zunyi Normal University(No.BS[2018]04)the Qian Ke He Zhicheng(2018)2778.
文摘The Lenghu area is one of the most crucial tectonic belts for oil and gas exploration in the Qaidam Basin.However,reservoir distribution and the factors controlling petroleum accumulation in this area have not been studied in detail.In this paper,the structural characteristics and controlling factors of oil and gas accumulation in the Lenghu belt are investigated based on seismic profiles combined with drilling logs and microphotographs data.Results indicate that the Lenghu belt has thick source rocks and has preserved hydrocarbon generation conditions.Moreover,structural characteristics and lithology are the key factors controlling the reservoir distribution.The production of oil and gas layers are mainly distributed in high structural points and weak stress zones.The fracture zones and the weak stress zones are the potential places for the distribution of oil and gas reservoirs.
基金Supported by the China National Science and Technology Major Project(2016ZX05050 2017ZX05013-004)
文摘Based on the previous studies and development practice in recent 10 years, a quantitative evaluation method for the adaptability of well patterns to ultra-low permeability reservoirs was established using cluster analysis and gray correlation method, and it includes 10 evaluation parameters in the four aspects of optimal evaluation parameters, determination of weights for evaluation parameters, development stage division, and determination of classification coefficients. This evaluation method was used to evaluate the well pattern adaptability of 13 main ultra-low permeability reservoirs in Triassic Chang 6 and Chang 8 of Ordos Basin. Three basic understandings were obtained: Firstly, the well pattern for ultra-low permeability type-I reservoirs has generally good adaptability, with proper well pattern forms and well pattern parameters. Secondly, square inverted nine-spot well pattern is suitable for reservoirs with no fractures; rhombic inverted nine-spot injection pattern is suitable for reservoirs with some fractures; and rectangular well pattern is suitable for reservoirs with rich fractures. Thirdly, for the ultra-low permeability type-Ⅱ and type-Ⅲ reservoirs, with the principles of well pattern form determination, the row spacing needs to be optimized further to improve the level of development of such reservoirs.
基金funding support of this project from National Science and Technology Major Project of the Ministry of Science and Technology of China (Grant No. 2011ZX05010-002-005)
文摘1 Introduction Reservoir architecture analysis of distributary channel of Daqing oilfield has drawn consistent interest among development geologists and petroleum engineers over the last decade(Lv et al.,1999;Zhou et al.,2008;Zhang et
文摘In this paper, first, based on landscape ecology theories, we respectively selected indexes from 4 aspects, area, edge, shape, and density, of the landscape type to describe the status of forest landscape patterns, and we established the stability index of landscape pattern (LSBI). Then, based on geo-statistical theories, we divided the forest in the reservoir area into 3990 grids of 4 km × 4 km using network technology and employing ordinary Kriging modelling to make trend surface analyses of the forest resources in the reservoir area. Finally, based on statistics principles, we used sampling theory to systematically extract 227 samples to obtain 7 periods of remote-sensing data from 1990a to 2012a. Then, we classified and extracted the forest in the sampling area using remote sensing, and we analysed each result with an Autoregressive Integrated Moving Average Model (ARIMA) time-series model. The results indicated the following: 1) the landscape structure of the reservoir area was primarily needle-leaved forest, broad-leaved forest and bush forest, and the mixed stands and bamboo stands were secondary;2) the difference of the forest landscape pattern stability in the reservoir area, in all directions, was not significant, but the southern region was slightly more stable;and 3) the stability of the forest landscape pattern in the reservoir area increased from 1990a to 2012a. It kept increasing until 2016a. This study provides a theoretical basis for the reasonable management and decisions about the forest resources in the Three Gorges Reservoir Area. Meanwhile, it also explores methods for relevant research and has practical significance.
文摘This paper studied the distribution and utilization status, reasonable exploitation patterns and potential productivity, and sustainable development of marginal lands in the Three Gorge Reservoir Areas. It has been pointed that problems of the soil fertility degradation, poor productivity in crop lands, natural disasters and environmental deterioration existed in all the exploited marginal lands. In order to maintain the sustainability of the marginal lands, following measure have been proposed: prohibiting cultivation in the crop lands with a slope more than 25°, restoring vegetation in the slope more than 25°, strengthening the basic agricultural construction, establishing the production base of woody feeds and oils, establishing a multi dimensional management model with reasonable structure and optimum function for forestry, agriculture and fishing.
基金Supported by National Natural Science Foundation of China(41471234)Chongqing Basic and Cutting-edge Research Project(cstc2015jcyjB X0141)+2 种基金Natural Science Foundation of Chongqing(CSTC,2010BB0326)Social Sciences Project of Chongqing Municipal Education Commission(08JWSK043)Ph.D.Fund Project of Chongqing Normal University(05XLB)
文摘In this study,taking the typical terracing land in Wushan County of Chongqing Municipality for example,we study the distribution of soil nutrients in the terracing land under different land use patterns in Three Gorges Reservoir Area. We conduct field survey and sampling on three different land use patterns( cash crop land,food crop land and abandoned land),and do the indoor experimental analysis of soil nutrient indicators. The results indicate that there is significant or very significant impact on soil nutrients under different land use patterns. The content of soil organic matter declines in sequence from abandoned land,food crop land to cash crop land; the content of soil N declines in sequence from cash crop land,abandoned land to food crop land; the content of soil P declines in sequence from cash crop land,food crop land to abandoned land; the content of soil K declines in sequence from abandoned land,cash crop land to food crop land. The result is in close relation to land use patterns,human cultivation activity,land disturbance and application of fertilizer.
基金funded by SINOPEC Science and Technology Research Program(No.P23206No.P23230).
文摘Coal-measure gas is a primary target with significant potential for the exploration of unconventional hydrocarbon resources.However,the spatiotemporal distribution and combination patterns of multi-type coal-measure gases are yet to be clarified,directly impeding the sweet spot evaluation and exploration deployment of coal-measure gas.This study discussed the characteristics and distribution patterns of coal-measure gases in the Daniudi gas field in northeastern Ordos Basin,China,with abundant drilling data.The results indicate that the coal seams variably thin upward and are mainly seen in the first and second members of the Taiyuan Formation(also referred to as the Tai 1 and Tai 2 members,respectively)and the first member of the Shanxi Formation(Shan 1 Member).Nos.8,5 and 3 coal seams are laterally continuous,and significantly thicker in its southern part compared to the northern part.Moreover,carbonaceous mudstones and shales are better developed in the southern part,where limestones are only observed in the Tai 1 Member.Based on the main lithological types,we identified three lithologic roofs of coal seams,that is,limestone,mudstone,and sandstone,which determine the spatiotemporal distribution of coal-measure gases.Besides bauxite gas in the Benxi Formation,the coal-measure gases include tight-sand gas,coalbed methane(CBM),coal-measure shale gas,and tight-limestone gas,with CBM typically associated with coal-measure shale gas.The combinations of different types of coal-measure gas vary across different layers and regions.Tight-sand gas is well-developed in areas where tight sandstones are in contact with coal-measures.From the Taiyuan to the Shanxi formations,CBM gradually transitions into a combination of CBM and coal-measure shale gas,and coal-measure shale gas.Nos.8 and 5 coal seams in low-lying areas exhibit favorable gas-bearing properties due to their large thickness and favorable roof lithologies,serving as prospective play fairways.Mudstone and limestone roofs are more conducive to achieving good gas-bearing properties.The direct contact between sandstones and coal seams tends to result in the formation of tight-sand gas and a reduced gas content of CBM.While focusing on single types of gas reservoirs such as CBM and tight-sand gas,it is essential to consider the concurrent exploration of various coal-measure gas combinations to discover more additional gas resources and guide exploration deployment.
基金Supported by the China National Science and Technology Major Project(2016ZX05014-003-004)
文摘Based on the similarity criterion, volcanic rock samples were taken from outcrops to make experimental models. Water flooding experiments of five-spot well pattern, nine-spot well pattern, five-spot to nine-spot well pattern, the relationship between relative well and fracture positions, and injection rate in dissolution vug-cave reservoirs with/without fractures were carried out to analyze variation regularities of development indexes, find out development characteristics of water flooding with different well patterns and sort out the optimal water flooding development mode. For dissolution vug-cave reservoirs without fractures, five-spot well pattern waterflooding has very small sweeping area, serious water channeling and low oil recovery. When the well pattern was adjusted from five-spot to nine-spot well pattern, oil recovery could be largely improved, but the corner well far from the injector is little affected. In dissolution vug-cave reservoirs with fractures, when the injector and producer are not connected by fractures, the fractures could effectively connect the poorly linked vugs to improve the development effect of water flooding. Whether there are fractures or not in dissolution vug-cave reservoirs, the development effect of nine-spot well-pattern is much better than that of five-spot well pattern and five-spot to nine-spot well pattern, this is more evident when there are fractures, and the edge well has better development indexes than corner well. At the high-water cut stage of water flooding with nine-spot well pattern, the oil recovery can be further improved with staggered line-drive pattern by converting the corner well into injection well. It is helpful to increase the oil production of corner well of nine-spot well pattern by increasing the injection rate, and improve ultimate oil recovery, but the water-free production period would be greatly shortened and water-free recovery would decrease.
文摘For thin oil rim reservoir with gas cap and edge water, it is helpful to improve the development effect to find out the distribution law of remaining oil in this kind of reservoirs. For this reason, taking the narrow oil rim reservoir with gas cap and edge water of Oilfield A in Bohai Sea as a case, the main controlling factors, including reservoir structure, fault, gas cap energy, edge water energy and well pattern, affecting the distribution of residual oil in this kind of reservoir were analyzed by using the data of core, logging, paleogeomorphology and production. Then, the distribution law of remaining oil was summarized. Generally, the remaining oil distribution is mainly potato-shaped or strip-shaped in plane. Vertically, it depends on the energy of gas cap and edge water. For the reservoir with big gas gap and weak edge water, the remaining oil mainly lies in the bottom of oil column. And for the reservoir with small gas gap and strong edge water, the remaining oil mainly locates at the top of oil column. Aiming at different distribution modes of remaining oil, the corresponding potential tapping strategies of horizontal wells are put forward: in the late stage of development, for the reservoir with big gas gap and weak edge water, the remaining oil concentrates at the bottom of the oil column, and the position of horizontal well should be placed at the lower 1/3 to the lower 1/5 of the oil column;for the reservoir with small gas cap and strong edge water, the remaining oil locates at the top of the oil column, and the position of horizontal well should be put at the upper 1/5 to the upper 1/3 of the oil column height, vertically. Based on the study on remaining oil of Oilfield A, a potential tapping strategy of well pattern thickening and vertical position optimization of horizontal well was proposed. This strategy guided the efficient implementation of the comprehensive adjustment plan of the oilfield. Moreover, 18 infill development wells were implemented in Oilfield A, and the average production of the infill wells is 2.1 times that of the surrounding old wells. It is estimated that the ultimate recovery factor of the oilfield will reach 33.9%, which is 2.3% higher than that before infilling wells. This study can be used for reference in the development of similar reservoirs.
基金financial support from"Major Projects about Carbonate Reservoirs of Petrochina (2008E-0610-08)""Young Innovation Fund Project of Research Institute of Petroleum Exploration and Development (2009-A-17-13)"
文摘Carbonate reservoir patterns play an important role in the production performance of oil and gas wells,and it is usually classified through static data analysis which cannot reflect the actual well performance.This paper takes the Tazhong No.1 gas field in the Tarim Basin,China as an example to investigate the classification of carbonate reservoirs.The classification method mainly combines well test analysis with production analysis—especially the Blasingame type curve method.Based on the characteristics of type curves for well test analysis and the Blasingame method,the relationship between the type curves and reservoir pattern was established.More than 20 wells were analyzed and the reservoirs were classified into 3 major patterns with 7 sub-classes.Furthermore,the classification results were validated by dynamic performance analysis of wells in the Tazhong No.1 gas field.On the basis of the classification results,well stimulation（i.e.water flooding in a single well） was carried out in three volatile-oil wells,and the oil recovery increased by up to 20%.
基金Sponsored by Scientific and Research Foundation of Yunnan Provincial Education Department (08Y0303)S&T Innovation Team Project of Bio-diversity Protection of Qujing Normal University~~
文摘By using TM remote sensing images of Baiyangdian Wetland in 1989,1999,2003 and 2004,taking the water area between Anxin County and Cangzhou where most of Baiyangdian Wetland water body lies for landscape classification,changes in landscape pattern of Baiyangdian before and after the water supplement were analyzed with landscape indexes calculated by Fragstats3.3. The results showed that after the water supplement,from the perspective of landscape cell index,fractal dimension of major ecosystems in Baiyangdian decreased to some extent;from the perspective of landscape diversity index,diversity index of the study region also decreased,which demonstrated that ecosystem diversity in this region reduced,land cover grew to simplification;and the decreasing evenness degree of the study region also showed the uneven development of its ecosystems. That is to say,water supplement has brought favorable ecological changes to the eco-environment of Baiyangdian,which has further optimized the health condition of ecosystems in this region.
文摘The genesis of the Ordovician karst in the Tahe Oilfield is hypothesized on the basis of many analyses of the geo-chemical data and the sporopollen. Ordovician carbonate rocks experienced multistage karst reconstructions under the condition of low-temperature oxidation meteoric water on the surface or near-surface. The karst occurred mainly in the early Hercynian, which has undergone three stages of karst cycle and developed three sets of cave reservoirs under the influence of the tectonic uplift, and the upper of the cave was formed earlier. The evidence of karst was found in the Caledonian. On the above basis, the genetic prediction pattern of the Ordovician palaeokarst reservoir in this region was set up.
