The Optimization And Field Application Of Completion Fluid System For Sidewall Purification

As an important technology to protect the reservoir,completion fluid technology in oilfield plays an important role to increase production of oil and gas Wells.The existing completion fluid technology in TUHA oilfield can effectively protect reservoir and improve production in the process of completion,but because the completion fluid formula does not add treatment agent to clean up mud cake,the oil soluble rate of completion fluid is low,so it can not effectively remove the sidewall mud cake,hindered the connectivity of reservoir space and borehole.Therefore,on the basis of the existing technology,it is necessary to optimize the performance of the completion fluid to remove mud cake,improve the completion fluid formula and process technical measures.Through the analysis of the characteristics of drilling fluid additives,as well as drilling fluid filter cake properties in TUHA oilfield,and studied the cake removal mechanism.the acid organic chelating agent S2 as filter cake scavenger can effectively dissolve the cake of drilling fluid,the addition amount is 0.5%,and the weight loss can reach 21.9 %.Optimum inhibitor HS1,add 3%,The corrosion rate of N80 steel sheet is 0.097 mm / a,which effectively reduces the corrosion of drilling tools and downhole tools.By evaluating the oil soluble temporary plugging agent ZD1,the oil soluble rate is more than 90%.The recovery rate of core permeability is more than 90.2% %,which can effectively protect the reservoir.The completion fluid system has applied in Tuha Lu Keqin oilfield and Yan Muxi oilfield for 11 Wells with no site construction complex and the effective rate is 100 %,the average initial yield is increased by 21.8 % and 8.1 % respectively than adjacent Wells.The new completion fluid using mud cake removing technology can effectively remove the mud cake attached on the wall,open the connecting channels of reservoir pore and wellbore,and can improve the reservoir permeability,actively and protect the reservoirs,and significantly reduce the damage to production in completion process,which is of practical significance to improve the production.