Displacement efficiency is an important index of water drive oilfield. This article takes water drive oilfield as the object to analyze the influence factors of displacement efficiency in limit water cut stage of wate...Displacement efficiency is an important index of water drive oilfield. This article takes water drive oilfield as the object to analyze the influence factors of displacement efficiency in limit water cut stage of water drive oilfield. The displacement efficiency experimental data of 99 cores which come from 65 development wells of 34 oilfields have been collected. The authors use the method of multiple linear regression analysis to establish a new empirical formula of displacement efficiency. The relative error of the empirical formula is less than 7% compared to the experimental data.展开更多
Using core, logging and other data, combined with field outcrop deposition, this paper studies the sedimentary genetic types and sedimentary stages of thick sandy braided river interlayer in C oilfield, and divides tw...Using core, logging and other data, combined with field outcrop deposition, this paper studies the sedimentary genetic types and sedimentary stages of thick sandy braided river interlayer in C oilfield, and divides two stages of interlayer and three single-stage braided flow zones. On this basis, geostatistical inversion constrained by logging and discerning River quantitative knowledge base is carried out to predict the distribution range of the main interlayer in the two phases. The production performance test of the blind well and horizontal well shows that the coincidence rate of the prediction results of interlayer with thickness > 1.5 m is 75%. The research shows that the first stage is the main interlayer, mainly composed of mudstone of flood plain origin, with an average thickness of 2.1 m and relatively stable distribution. Based on the interlayer prediction results, the small layer of composite sand body 1 forms a residual oil enrichment area in the high part of the structure due to the wide range of interlayer shielding in the lower part, which is a favorable area for adjusting and tapping potential.展开更多
Core, well logging and seismic data were used to investigate sandbody architectural characteristics within Lower Member of Minghuazhen Formation in Neogene, Bohai BZ25 Oilfield, and to analyze the sedimentary microfac...Core, well logging and seismic data were used to investigate sandbody architectural characteristics within Lower Member of Minghuazhen Formation in Neogene, Bohai BZ25 Oilfield, and to analyze the sedimentary microfacies, distribution and internal architecture characteristics of the bar finger within shoal water delta front. The branched sand body within shoal water delta front is the bar finger, consisting of the mouth bar, distributary channel over bar, and levee. The distributary channel cuts through the mouth bar, and the thin levee covers the mouth bar which is located at both sides of distributary channel. The bar finger is commonly sinuous and its sinuosity increases basinward. The distributary channel changes from deeply incising the mouth bar to shallowly incising top of the mouth bar.The aspect ratio ranges from 25 to 50 and there is a double logarithmic linear positive relationship between the width and thickness for the bar finger, which is controlled by base-level changing in study area. For the bar finger, injection and production in the same distributary channel should be avoided during water flooding development. In addition, middle–upper distributary channel and undrilled mouth bar are focus of tapping remaining oil.展开更多
In order to solve dynamic problems caused by the internal structure of fluvial reservoir,it is necessary to study the fine anatomy of point bar. Taking Minghuazhen Formation in the northern block of Q oilfield,Bohai S...In order to solve dynamic problems caused by the internal structure of fluvial reservoir,it is necessary to study the fine anatomy of point bar. Taking Minghuazhen Formation in the northern block of Q oilfield,Bohai Sea as an example,the authors studied identification marks,distribution pattern and scale of point bar based on coring,logging and dynamic data. The results show that the length of point bar and the width of lateral accretion body are 713--911 m and 71--111 m,respectively; the dip angle and the thickness of lateral accretion bedding are 3. 5°--5. 9° and 0. 1--0. 5 m. The lateral accretion beddings are the key factor affecting the seepage velocity of the tracer.展开更多
Reservoir connectivity is a critical issue in the process of oil-gas exploration and development. According to the theory of fluid mechanics and the achievements of many scholars, a connected reservoir coincides with ...Reservoir connectivity is a critical issue in the process of oil-gas exploration and development. According to the theory of fluid mechanics and the achievements of many scholars, a connected reservoir coincides with a unified formation pressure system;there is a linear relationship between formation pressure and depth in normal pressure system reservoir. However, in high-permeability or multi-phase fluid reservoirs, this method has poor applicability and limitations. Through theoretical analysis and formula derivation, a new method for judging the connectivity of normal pressure reservoirs is found, that is, the inverse proportional function relationship between the pressure coefficient and the depth. In this paper, the relationship between the pressure system and the inverse proportional function has been verified. The function of the same pressure system is unique, monotonic, and has unified asymptote and symmetry axis and vice versa. Examples show that the inverse proportional function is more accurate and reliable for judging reservoir connectivity than the linear function.展开更多
Bozhong oilfield which is abbreviated as BZ oilfield is the first oilfield with deep metamorphic buried hill that is discovered reserves of billion-ton in Bohai Bay. Affected by multi-stage tectonic movements, the dis...Bozhong oilfield which is abbreviated as BZ oilfield is the first oilfield with deep metamorphic buried hill that is discovered reserves of billion-ton in Bohai Bay. Affected by multi-stage tectonic movements, the distribution of fractures is very complex in this area, therefore it is significant to study the evolution of structures for understanding the distribution of fractures. In view of the complexity on the tectonic evolution of the buried hill region in the study area, the influence of tectonic movements on the formation of fractured reservoir is analyzed, and the research results lay the foundation for the efficient development in this type of the oilfield. The results show that main faults, which is formed during early Indosinian and Yanshanian period, are mainly developed in the BZ oilfield area, and the fracture strike has mainly east-west and north-east-east trend. Based on the analysis of the relationship among tectonic evolution, regional stress field and fracture development, it is considered that Indosinian extrusion is the main reason for the formation of main direction faults in the study area. Yanshanian strike-slip transformation and Himalayan reactivation further controlled the development of the fractured reservoirs in the later stage, and formed the present fracture network system. Well block 5 is located in passive plate system during Indosinian period, it is affected by Himalayan stretching and long-term activation of large faults in the later stage, so that the effective fractures are relatively developed. The result plays an important role in guiding the overall plan deployment of the BZ oilfield.展开更多
文摘Displacement efficiency is an important index of water drive oilfield. This article takes water drive oilfield as the object to analyze the influence factors of displacement efficiency in limit water cut stage of water drive oilfield. The displacement efficiency experimental data of 99 cores which come from 65 development wells of 34 oilfields have been collected. The authors use the method of multiple linear regression analysis to establish a new empirical formula of displacement efficiency. The relative error of the empirical formula is less than 7% compared to the experimental data.
文摘Using core, logging and other data, combined with field outcrop deposition, this paper studies the sedimentary genetic types and sedimentary stages of thick sandy braided river interlayer in C oilfield, and divides two stages of interlayer and three single-stage braided flow zones. On this basis, geostatistical inversion constrained by logging and discerning River quantitative knowledge base is carried out to predict the distribution range of the main interlayer in the two phases. The production performance test of the blind well and horizontal well shows that the coincidence rate of the prediction results of interlayer with thickness > 1.5 m is 75%. The research shows that the first stage is the main interlayer, mainly composed of mudstone of flood plain origin, with an average thickness of 2.1 m and relatively stable distribution. Based on the interlayer prediction results, the small layer of composite sand body 1 forms a residual oil enrichment area in the high part of the structure due to the wide range of interlayer shielding in the lower part, which is a favorable area for adjusting and tapping potential.
基金Supported by the National Natural Science Foundation of China(41772101)China National Science and Technology Major Project(2017ZX05009001-002)
文摘Core, well logging and seismic data were used to investigate sandbody architectural characteristics within Lower Member of Minghuazhen Formation in Neogene, Bohai BZ25 Oilfield, and to analyze the sedimentary microfacies, distribution and internal architecture characteristics of the bar finger within shoal water delta front. The branched sand body within shoal water delta front is the bar finger, consisting of the mouth bar, distributary channel over bar, and levee. The distributary channel cuts through the mouth bar, and the thin levee covers the mouth bar which is located at both sides of distributary channel. The bar finger is commonly sinuous and its sinuosity increases basinward. The distributary channel changes from deeply incising the mouth bar to shallowly incising top of the mouth bar.The aspect ratio ranges from 25 to 50 and there is a double logarithmic linear positive relationship between the width and thickness for the bar finger, which is controlled by base-level changing in study area. For the bar finger, injection and production in the same distributary channel should be avoided during water flooding development. In addition, middle–upper distributary channel and undrilled mouth bar are focus of tapping remaining oil.
基金Supported by Project of Fine Reservoir Description Technology of Heavy Oil Reservoir(No.1507)
文摘In order to solve dynamic problems caused by the internal structure of fluvial reservoir,it is necessary to study the fine anatomy of point bar. Taking Minghuazhen Formation in the northern block of Q oilfield,Bohai Sea as an example,the authors studied identification marks,distribution pattern and scale of point bar based on coring,logging and dynamic data. The results show that the length of point bar and the width of lateral accretion body are 713--911 m and 71--111 m,respectively; the dip angle and the thickness of lateral accretion bedding are 3. 5°--5. 9° and 0. 1--0. 5 m. The lateral accretion beddings are the key factor affecting the seepage velocity of the tracer.
文摘Reservoir connectivity is a critical issue in the process of oil-gas exploration and development. According to the theory of fluid mechanics and the achievements of many scholars, a connected reservoir coincides with a unified formation pressure system;there is a linear relationship between formation pressure and depth in normal pressure system reservoir. However, in high-permeability or multi-phase fluid reservoirs, this method has poor applicability and limitations. Through theoretical analysis and formula derivation, a new method for judging the connectivity of normal pressure reservoirs is found, that is, the inverse proportional function relationship between the pressure coefficient and the depth. In this paper, the relationship between the pressure system and the inverse proportional function has been verified. The function of the same pressure system is unique, monotonic, and has unified asymptote and symmetry axis and vice versa. Examples show that the inverse proportional function is more accurate and reliable for judging reservoir connectivity than the linear function.
文摘Bozhong oilfield which is abbreviated as BZ oilfield is the first oilfield with deep metamorphic buried hill that is discovered reserves of billion-ton in Bohai Bay. Affected by multi-stage tectonic movements, the distribution of fractures is very complex in this area, therefore it is significant to study the evolution of structures for understanding the distribution of fractures. In view of the complexity on the tectonic evolution of the buried hill region in the study area, the influence of tectonic movements on the formation of fractured reservoir is analyzed, and the research results lay the foundation for the efficient development in this type of the oilfield. The results show that main faults, which is formed during early Indosinian and Yanshanian period, are mainly developed in the BZ oilfield area, and the fracture strike has mainly east-west and north-east-east trend. Based on the analysis of the relationship among tectonic evolution, regional stress field and fracture development, it is considered that Indosinian extrusion is the main reason for the formation of main direction faults in the study area. Yanshanian strike-slip transformation and Himalayan reactivation further controlled the development of the fractured reservoirs in the later stage, and formed the present fracture network system. Well block 5 is located in passive plate system during Indosinian period, it is affected by Himalayan stretching and long-term activation of large faults in the later stage, so that the effective fractures are relatively developed. The result plays an important role in guiding the overall plan deployment of the BZ oilfield.