Mechanism Analysis Of The Rising Water Cut After The Operation And Experimental Study Of Control Technology In Bonan Oilfield

Bonan oilfield is a medium-high water cut oilfield, of which water cut rises up, liquid and oil producing capacity descend, water absorbing capacity falls. The development effect of Bonan oilfield is affected by many factors such as high well depth, high temperature of the formation, high pressure, low permeable sublayer, bad adaptiveness of the reservoir technologic measures, especially by the rising water cut of oil well after acidizing and cleaning out operations. Using theoretical analysis and in-house experiment approaches which unite reservior geologic condition of Bonan oilfield, based on analysing the aeolotropy and the sensitivity of reservoir for the fifth and sixth division of Bonan oil field. The penetration law of oil/water and the variance law of water cut for low permeable sublayer oil field was studied, and the main cause of the rising water cut after operation was analysed. The experiment for finding control technology of the rising water cut after the operation was runned. The treatings which use to control the rising of water cut after acidizing and to raise the oil production of acidizing by choosing fitting acidizing fluid system and using effective acid additive by means of experiment were researched. And the method to control the rising water cut after killing well and cleanning out operation by controlling solid matter content of the entering well fluid, using water based foam or oil based foam to decrease the pollution of reservoir by the entering well water and using backwater joined with additive to decrease the extent of damage of reservoir was also studied. The research has important theory guiding value for controlling the rising water cut for low permeable sublayer oilfield after operation, and can fulfill the requirement of stably yielding production for the oilfield.