Evaluating And Studying The Property Of Selective Plugging Agent In The North Of QHD32-6 Oilfield

QHD32-6 Oilfield is a heavy offshore thickened oilfield. Water production of oil well becomes a serious problem with the improvement of recovery percent. Problems increase difficulties to block off water, such as the small platform space, short operation cycle, high development cost, complicated geological conditions, high comprehensive water cut and so on.This paper researched several common plugging agents’ gel-forming properties under the condition of QHD32-6 oilfield reservoir, and picked out AMPS/Cr3+ cross linking system which has a better gel-forming property, and optimized the formula of plugging agent(0.05%~0.1%AMPS+0.4%~0.6%Cr3+) by studying the effects of polymer concentration and crosslinking agent concentration on gelation properties. PH value, the salinity in water, the temperature and other factors that have effects on the viscosity of cross linking system were studied and the results show that crosslinking system has good sealing performance under reservoir conditions. The cross linking system’s properties of plugging performance, oil-water selectivity and scouring resistance were studied by doing the simulation experiment of sand flow in the pipe. The study results of the mechanism showed that selective blocking agents plugging water without plugging oil through the function of polymer’s static adsorption, trapping, physical blockages and retention of dynamic.The process parameters of Water plugging in B21 oil well in the north of QHD32-6 oilfield were optimized and designed. The reasonable plugging radius was confirmed to be 12~15 meters, 2 slug combinations were designed to reduce the blocking agent dosage.