Method Of Determination Of Water Cut Of Putaohua Reservoir In G Area With Resistivity Log

Since it has been shown that reservoirs in Putaohua formation of Daqing G area have the characters of high clay content and complicated pore structures and complicated fluid property,in order to improve the judgement of fluid property accurately and the calculation accuracy of the relative ratio of oil and water production,we put forward the research of using the resistivity log to determine the reservoir water production rate. In this paper,according to the characteristics of Putaohua reservoirs, the concept of three-water is introduced, and water of total pore of shaly sand is divided into movable water, capillary bound water and clay bound water. According to the model of bending capillary,it assumes that movable water pore is made of n capillaries, combining Poiseuille equation and Darcy’s law,derivation of the relationship among water relative permeability and the water saturation and the equivalent tortuosity of fliud flow.Using three-pore conductivity model,derivation of the relationship of resistivity index of porosity of movable fluid merely and the water saturation and the equivalent tortuosity of fliud flow.According to the assumption of similarity between water flow and electric current in movable fluid pore, the relationship among water relative permeability, water saturation and the resistivity index is established for shaly rock.According to quantity relationship of each component volume of movable fluid and the concept of specific surface, the relationship of water relative permeability and oil relative permeability is derived.From that, the relationship among oil relative permeability, water saturation and the resistivity index can be derived for shaly rock. According to the equivalent rock element theory,according to the same flow rate in large and small porosity,combining Poiseuille equation and Darcy’s law and according to the assumption of similarity between the fluid and the electric flow,derivation of the relationship among oil-water relative permeability and the water saturation and the pore structure efficiency.Combined with the model of pore structure efficiency and the theory of triple pore conductivity,derivation of the relationship among the resistivity index and the water saturation and the pore structure efficiency. And then, the relationship among oil-water relative permeability and the water saturation and the resistivity index is derivated. The experimental relation curves of water-oil relative permeability are obtained by mercury penetration data and the Burdine model, according to the model of triple pore conductivity and the equivalent rock element theory, the resistivity index can be derivated by using rock conductive rule in the same sample.On this basis,validation the model of the oil-water relative permeability and resistivity of shaly rock by experimental.The water cut in the reservoirs can be determined by the relationship between oil-water relative and water cut.The parameters interpretation method of clay content,porosity and the irreducible water saturation can be determined by core analysis data and logging data.Practical data is processed by the method of water cut prediction of this paper,the result indicates that the method can predict the water cut of reservoirs in Putaohua formation of Daqing G areaaccurately.