Oil saturation was an important parameter of reservoir evaluation, which had important guiding significance for oilfield development. In this paper, the oil saturation of tight oil in G area was studied, and the origi...Oil saturation was an important parameter of reservoir evaluation, which had important guiding significance for oilfield development. In this paper, the oil saturation of tight oil in G area was studied, and the original oil saturation of the study area was studied by using the comprehensive experimental method. The original oil saturation of tight oil in the study area was determined by J function method, rock electricity method and oil-based mud coring method. The results showed that through the comparison of three experimental methods, it could be concluded that the J function method leads to the low value of oil saturation in the study area. The oil-based mud coring method was more suitable for the determination of oil saturation in this area than the other two methods because it needs to meet too many conditions and the calculation results were also low. G area was located in Qili Village, Ordos Basin.展开更多
To solve the problem that it is difficult to identify carbonate low resistivity pays(LRPs) by conventional logging methods in the Rub Al Khali Basin, the Middle East, the variation of fluid distribution and rock condu...To solve the problem that it is difficult to identify carbonate low resistivity pays(LRPs) by conventional logging methods in the Rub Al Khali Basin, the Middle East, the variation of fluid distribution and rock conductivity during displacement were analyzed by displacement resistivity experiments simulating the process of reservoir formation and production, together with the data from thin sections, mercury injection and nuclear magnetic resonance experiments. In combination with geological understandings, the genetic mechanisms of LRPs were revealed, then the saturation interpretation model was selected, the variation laws and distribution range of the model parameters were defined, and finally an updated comprehensive saturation interpretation technique for the LRPs has been proposed. In the study area, the LRPs have resistivity values of less than 1 Ω·m, similar to or even slightly lower than that of the water layers. Geological research reveals that the LRPs were developed in low-energy depositional environment and their reservoir spaces are controlled by micro-scale pore throats, with an average radius of less than 0.7 μm, so they are typical microporous LRPs. Different from LRPs of sandstone and mudstone, they have less tortuous conductive paths than conventional reservoirs, and thus lower resistivity value under the same saturation. Archie’s formula is applicable to the saturation interpretation of LRPs with a cementation index value of 1.77-1.93 and a saturation index value of 1.82-2.03 that are 0.2-0.4 lower than conventional reservoirs respectively. By using interpretation parameters determined by classification statistics of petrophysical groups(PGs), oil saturations of the LRPs were calculated at bout 30%-50%,15% higher than the results by conventional methods, and basically consistent with the data of Dean Stark, RST, oil testing and production. The 15 wells of oil testing and production proved that the coincidence rate of saturation interpretation is over 90%and the feasibility of this method has been further verified.展开更多
The original oil saturation of the reservoir is of vital importance for reservoir evaluation and calculation of geological reserves.To determine the original oil saturation of the reservoir and provide a reference for...The original oil saturation of the reservoir is of vital importance for reservoir evaluation and calculation of geological reserves.To determine the original oil saturation of the reservoir and provide a reference for reservoir evaluation and geological reserve calculation,this paper takes the sandstone of the Chang 9 oil layer group in the Zhouchang oil area of Wuqi Oilfield in the Ordos Basin as the research object.Based on core,logging,mud logging and well testing data,combined with experimental data,four methods,namely the closed core method,mercury injection method,relative permeability method and logging interpretation method,are used to calculate the original oil saturation of the Chang 9 oil layer in the northeastern Wuqi area.The advantages and disad-vantages of each method are analyzed to determine the original oil saturation that is suitable for the Chang 9 oil layer group in this area and thereby improve the accuracy of reserve calculation.The results show that the comprehensive logging interpretation method is the best method for calculating the original oil saturation in this area,and the original oil saturation is finally determined to be 54.6%.展开更多
文摘Oil saturation was an important parameter of reservoir evaluation, which had important guiding significance for oilfield development. In this paper, the oil saturation of tight oil in G area was studied, and the original oil saturation of the study area was studied by using the comprehensive experimental method. The original oil saturation of tight oil in the study area was determined by J function method, rock electricity method and oil-based mud coring method. The results showed that through the comparison of three experimental methods, it could be concluded that the J function method leads to the low value of oil saturation in the study area. The oil-based mud coring method was more suitable for the determination of oil saturation in this area than the other two methods because it needs to meet too many conditions and the calculation results were also low. G area was located in Qili Village, Ordos Basin.
基金Supported by the CNPC Scientific Research and Technology Development Project (2019D-4410)。
文摘To solve the problem that it is difficult to identify carbonate low resistivity pays(LRPs) by conventional logging methods in the Rub Al Khali Basin, the Middle East, the variation of fluid distribution and rock conductivity during displacement were analyzed by displacement resistivity experiments simulating the process of reservoir formation and production, together with the data from thin sections, mercury injection and nuclear magnetic resonance experiments. In combination with geological understandings, the genetic mechanisms of LRPs were revealed, then the saturation interpretation model was selected, the variation laws and distribution range of the model parameters were defined, and finally an updated comprehensive saturation interpretation technique for the LRPs has been proposed. In the study area, the LRPs have resistivity values of less than 1 Ω·m, similar to or even slightly lower than that of the water layers. Geological research reveals that the LRPs were developed in low-energy depositional environment and their reservoir spaces are controlled by micro-scale pore throats, with an average radius of less than 0.7 μm, so they are typical microporous LRPs. Different from LRPs of sandstone and mudstone, they have less tortuous conductive paths than conventional reservoirs, and thus lower resistivity value under the same saturation. Archie’s formula is applicable to the saturation interpretation of LRPs with a cementation index value of 1.77-1.93 and a saturation index value of 1.82-2.03 that are 0.2-0.4 lower than conventional reservoirs respectively. By using interpretation parameters determined by classification statistics of petrophysical groups(PGs), oil saturations of the LRPs were calculated at bout 30%-50%,15% higher than the results by conventional methods, and basically consistent with the data of Dean Stark, RST, oil testing and production. The 15 wells of oil testing and production proved that the coincidence rate of saturation interpretation is over 90%and the feasibility of this method has been further verified.
文摘The original oil saturation of the reservoir is of vital importance for reservoir evaluation and calculation of geological reserves.To determine the original oil saturation of the reservoir and provide a reference for reservoir evaluation and geological reserve calculation,this paper takes the sandstone of the Chang 9 oil layer group in the Zhouchang oil area of Wuqi Oilfield in the Ordos Basin as the research object.Based on core,logging,mud logging and well testing data,combined with experimental data,four methods,namely the closed core method,mercury injection method,relative permeability method and logging interpretation method,are used to calculate the original oil saturation of the Chang 9 oil layer in the northeastern Wuqi area.The advantages and disad-vantages of each method are analyzed to determine the original oil saturation that is suitable for the Chang 9 oil layer group in this area and thereby improve the accuracy of reserve calculation.The results show that the comprehensive logging interpretation method is the best method for calculating the original oil saturation in this area,and the original oil saturation is finally determined to be 54.6%.
