修井作业中低渗漏压井液的研究和应用

Research and Application of Low Filtration Workover Fluid

由于地层压力下降，在修完井过程中易发生漏失现象，造成固相堵塞、液相圈闭等储层伤害。针对这一问题，研制出了低渗漏压井液。该低渗漏压井液采用高分子吸水材料作为低渗漏压井液的主剂，形成具有一定强度、软颗粒可变形、流动性良好、破胶性能好的固化水体系。其基本配方为：淡水（盐水）＋（1％～2％）固化剂＋0．5％胶体引发剂＋0．5％胶体保护剂＋0．2％盐水调节剂。室内实验表明，使用该压井液后，暂堵层迅速形成，中、低渗岩心暂堵层可承受20MPa压差而不发生渗漏，破胶后渗透率恢复值达到92．2％。现场应用2口井表明，该低渗漏压井液的暂堵性好，对储层的损害小，迅速恢复修井前产能或成功建产。

With formation pressure declining,reservoir damages,water block and solid plugging,are encountered because of lost circulation of workover fluid.To solve this problem,the low filtration workover fluid system is developed,which is made by water-absorbing material that can form high temperature and high pressure temporary plugging cake.The experimental results show that the temporary mud cake forms quickly,and middle or low permeability cores can be sealed under pressure difference of 20 MPa,moreover,the permeability recovery rate is 92.2%.The applications of two wells are successful that has the advantages of temporary plugging,low reservoir damage,and rapid restoration of productivity.