The Study Of Improving Recovery Ratio By Water Injection In Tahe Oil Field

This paper sets up reservoir's concept model of Ordovician fracture - cavity carbonate reservoir in TAHE oil field by the date of drilling,logging,core and so on; primarily analyses the character of formation water by formation water 's chemistry test date; calculates oil and water interface of 4 area in TAHE oil field by selecting pressure data on oil and water reservoir's pressure test date; analyses the elements of water injection oil recovery of single well and continuity wells on the base of scene experiment effect .the study result indicates:1,The structure factor of fracturing and cave unit has karst cave and fractures .The karst cave is mainly based on different degree filling-cave system, it is the primary reservoir space and seepage flow or flow duct. It can be described that one or multi-big conduit cave system connectted by natural fracturing and acid fracturing is formed on different stages and different water system or different stages in Ordovician compact carbonate. The flowing character of reservoir liquid in TAHE oil field is't ecumenic seepage but conduit flow.2,The paper considers that the formation water of 4area in TAHE oil field has the same chemic character in the course of exploitation. Aimming at the character of Ordovician fracture - cavity carbonate reservoir in TAHE oil field, oil and water interface of 4area is confirmed to 5720 meter after comparing with single well's result by fitting the oil and water interface of 4area by cross method of making use of hydrostatic pressure and oil reservoir testing pressure3,The elements of water injection oil recovery of single well by analyzing and studying is that the water takes place of the oil because of their different gravity, and forms a space of water injection at the bottom of fracture-cavity unit, and increases the formation pressure, enhances the elasticity energy of the natural oil, gradually enhances reservoir's recovery ratio because the oil and water interface is gradually heightened after repetitious water and oil replacement on water injection.4,The paper after analyzing development of many connectivity well groups of water injection thinks that the water injection at the bottom of fracture-cavity unit can have the effects of water and oil replacement on water injection,increasing the energy to its above oil wells after developing energy falls; the water injection at the bottom of fracture-cavity unit may also increase energy of wells that have underwater in the natural oil from the opposite direction,that can increase pressure, reduce containing water,and have the effect of suppressing water injection;it also can strengthen the intruding of water from the side or the bottom of wells to the above oil.