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
To clarify microscopic mechanisms of residual oil displacement by hydraulic pulsation wave,microscopic visualization experiments of hydraulic pulsation wave driving residual oil were carried out by using the microscop...To clarify microscopic mechanisms of residual oil displacement by hydraulic pulsation wave,microscopic visualization experiments of hydraulic pulsation wave driving residual oil were carried out by using the microscopic visualization device of pulsating water drive.For the four types of residual oil left in the reservoir after water flooding,i.e.membrane,column,cluster,and blind end residual oils,hydraulic pulsation waves broke the micro-equilibrium of the interface by disturbing the oil-water interface,so that the injected water invaded into and contacted with the remaining oil in small pores and blind holes,and the remaining oil was pushed or stripped to the mainstream channel by deformation superposition effect and then carried out by the injected water.In the displacement,the pulsation frequency mainly affected the cluster and blind end remaining oil,and the hydraulic pulsation wave with a frequency of about 1 Hz had the best effect in improving the recovery.The pulsation amplitude value mainly affected the membrane and column residual oil,and the larger the amplitude value,the more remaining oil the hydraulic pulsation wave would displace.The presence of low intensity continuous flow pressure and holding pressure end pressure promoted the concentration of pulsating energy and greatly improve the recovery of cluster residual oil.The rise in temperature made the hydraulic pulsation wave work better in displacing remaining oil,improving the efficiency of oil flooding.展开更多
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.
基金Supported by the National Natural Science Foundation of China(5187433951904320)National Key R&D Program(2020YFA0711804).
文摘To clarify microscopic mechanisms of residual oil displacement by hydraulic pulsation wave,microscopic visualization experiments of hydraulic pulsation wave driving residual oil were carried out by using the microscopic visualization device of pulsating water drive.For the four types of residual oil left in the reservoir after water flooding,i.e.membrane,column,cluster,and blind end residual oils,hydraulic pulsation waves broke the micro-equilibrium of the interface by disturbing the oil-water interface,so that the injected water invaded into and contacted with the remaining oil in small pores and blind holes,and the remaining oil was pushed or stripped to the mainstream channel by deformation superposition effect and then carried out by the injected water.In the displacement,the pulsation frequency mainly affected the cluster and blind end remaining oil,and the hydraulic pulsation wave with a frequency of about 1 Hz had the best effect in improving the recovery.The pulsation amplitude value mainly affected the membrane and column residual oil,and the larger the amplitude value,the more remaining oil the hydraulic pulsation wave would displace.The presence of low intensity continuous flow pressure and holding pressure end pressure promoted the concentration of pulsating energy and greatly improve the recovery of cluster residual oil.The rise in temperature made the hydraulic pulsation wave work better in displacing remaining oil,improving the efficiency of oil flooding.
