Factors affecting CO_(2) flooding of shale oil reservoir were studied by nuclear magnetic resonance(NMR) experiments, the effects of time, pressure, temperature on the recovery of CO_(2) flooding in shale oil reservoi...Factors affecting CO_(2) flooding of shale oil reservoir were studied by nuclear magnetic resonance(NMR) experiments, the effects of time, pressure, temperature on the recovery of CO_(2) flooding in shale oil reservoir were analyzed based on nuclear magnetic resonance T2 spectrum, and the effect of fracture development degree on recovery of CO_(2) flooding in shale oil reservoir was analyzed based on NMR images. In the process of CO_(2) flooding, the recovery degree of the shale oil reservoir gradually increases with time. With the rise of pressure, the recovery degree of the shale oil reservoir goes up gradually. With the rise of temperature, the recovery degree of shale oil increases first and then decreases gradually. For CO_(2) flooding in matrix core, the crude oil around the core surface is produced in the initial stage, with recovery degree going up rapidly;with the ongoing of CO_(2) injection, the CO_(2) gradually diffuses into the inside of core to produce the oil, and the increase of recovery degree slows down gradually. For CO_(2) flooding in matrix core with fractures, in the initial stage, the oil in and around the fractures are produced first, and the recovery degree goes up fast;with the extension of CO_(2) injection time, CO_(2) diffuses into the inside of the core from the fractures and the core surface to produce the oil inside the core, and the increase of recovery degree gradually slows down. Fractures increase the contact area between injected CO_(2) and crude oil, and the more the fractures and the greater the evaluation index of fractures, the greater the recovery degree of shale oil will be.展开更多
The BZ 34-1 oilfield is a typical gas cap edge water reservoir in the Bohai oilfield. The main characteristics of the oilfield were multi-phase sand body stacking and the sand body was composed of three parts: gas cap...The BZ 34-1 oilfield is a typical gas cap edge water reservoir in the Bohai oilfield. The main characteristics of the oilfield were multi-phase sand body stacking and the sand body was composed of three parts: gas cap, oil reservoir, and edge water. The actual production site results show that the permeability difference of multi-layer sand bodies has a serious impact on the development effect. This article establishes a typical reservoir model numerical model based on the total recovery degree of the reservoir and the recovery degree of each layer, and analyzes the impact of permeability gradient. As the permeability gradient increases, the total recovery degree of all four well patterns decreases, and the total recovery degree gradually decreases. The recovery degree of low permeability layers gradually decreases, and the recovery degree of high permeability layers gradually increases. As the permeability gradient increases, the degree of recovery gradually decreases under different water contents. As the permeability gradient increases, the reduction rate of remaining oil saturation in low permeability layers is slower, while the reduction rate of remaining oil saturation in high permeability layers was faster. By analyzing the impact of permeability gradient on the development effect of oil fields, we could further deepen our understanding of gas cap edge water reservoirs and guide the development of this type of oil field.展开更多
This paper proposes a method for determining the gas recovery of water-drive gas reservoirs. First, the water influx coefficient B in the theoretical formula Pr =（1-Rg）/（1-RgB） is used to determine the influence o...This paper proposes a method for determining the gas recovery of water-drive gas reservoirs. First, the water influx coefficient B in the theoretical formula Pr =（1-Rg）/（1-RgB） is used to determine the influence of the aquifer behavior. According to the theoretical formula, the relationship between the norrnalized pressure Pr and the degree of the reserve recovery Rg can be obtained with different values of B, which can be used to determine the activity level of the aquifer behavior. Second, according to Pra = （1-Rga）/（1-aEva） （where a = 1-Sgr/Sgi ）, the relationship between the normalized abandonment pressure Pra and the ultimate gas recovery Rga can be obtained, as the Agarwal end-point line. The intersection of the above two lines represents the value of the estimated ultimate gas recovery and the normalized abandonment pressure pra. Finally, an evaluation table and a set of demarcation charts are established, with different values of Sgr/Sgi and Eva as well as the water influx coefficient B, which can be used to determine the gas recovery of water-drive gas reservoirs with different activity levels of the aquifer behavior.展开更多
基金Basic and Forward-Looking Project of the Science and Technology Department of SINOPEC。
文摘Factors affecting CO_(2) flooding of shale oil reservoir were studied by nuclear magnetic resonance(NMR) experiments, the effects of time, pressure, temperature on the recovery of CO_(2) flooding in shale oil reservoir were analyzed based on nuclear magnetic resonance T2 spectrum, and the effect of fracture development degree on recovery of CO_(2) flooding in shale oil reservoir was analyzed based on NMR images. In the process of CO_(2) flooding, the recovery degree of the shale oil reservoir gradually increases with time. With the rise of pressure, the recovery degree of the shale oil reservoir goes up gradually. With the rise of temperature, the recovery degree of shale oil increases first and then decreases gradually. For CO_(2) flooding in matrix core, the crude oil around the core surface is produced in the initial stage, with recovery degree going up rapidly;with the ongoing of CO_(2) injection, the CO_(2) gradually diffuses into the inside of core to produce the oil, and the increase of recovery degree slows down gradually. For CO_(2) flooding in matrix core with fractures, in the initial stage, the oil in and around the fractures are produced first, and the recovery degree goes up fast;with the extension of CO_(2) injection time, CO_(2) diffuses into the inside of the core from the fractures and the core surface to produce the oil inside the core, and the increase of recovery degree gradually slows down. Fractures increase the contact area between injected CO_(2) and crude oil, and the more the fractures and the greater the evaluation index of fractures, the greater the recovery degree of shale oil will be.
文摘The BZ 34-1 oilfield is a typical gas cap edge water reservoir in the Bohai oilfield. The main characteristics of the oilfield were multi-phase sand body stacking and the sand body was composed of three parts: gas cap, oil reservoir, and edge water. The actual production site results show that the permeability difference of multi-layer sand bodies has a serious impact on the development effect. This article establishes a typical reservoir model numerical model based on the total recovery degree of the reservoir and the recovery degree of each layer, and analyzes the impact of permeability gradient. As the permeability gradient increases, the total recovery degree of all four well patterns decreases, and the total recovery degree gradually decreases. The recovery degree of low permeability layers gradually decreases, and the recovery degree of high permeability layers gradually increases. As the permeability gradient increases, the degree of recovery gradually decreases under different water contents. As the permeability gradient increases, the reduction rate of remaining oil saturation in low permeability layers is slower, while the reduction rate of remaining oil saturation in high permeability layers was faster. By analyzing the impact of permeability gradient on the development effect of oil fields, we could further deepen our understanding of gas cap edge water reservoirs and guide the development of this type of oil field.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.41274114,51274169)the Natio-nal Science and Technology Major Project of China(Grant No.2011ZX05045)
文摘This paper proposes a method for determining the gas recovery of water-drive gas reservoirs. First, the water influx coefficient B in the theoretical formula Pr =（1-Rg）/（1-RgB） is used to determine the influence of the aquifer behavior. According to the theoretical formula, the relationship between the norrnalized pressure Pr and the degree of the reserve recovery Rg can be obtained with different values of B, which can be used to determine the activity level of the aquifer behavior. Second, according to Pra = （1-Rga）/（1-aEva） （where a = 1-Sgr/Sgi ）, the relationship between the normalized abandonment pressure Pra and the ultimate gas recovery Rga can be obtained, as the Agarwal end-point line. The intersection of the above two lines represents the value of the estimated ultimate gas recovery and the normalized abandonment pressure pra. Finally, an evaluation table and a set of demarcation charts are established, with different values of Sgr/Sgi and Eva as well as the water influx coefficient B, which can be used to determine the gas recovery of water-drive gas reservoirs with different activity levels of the aquifer behavior.
