解除重晶石深度污染技术

A MEHTOD TO REMOVE HEAVY POLLUTION OF BARITE

塔里木盆地库车山前克深气田地层压力系数高,钻揭目的层时钻井液采用了大量的重晶石加重,因储层裂缝发育,重晶石固相侵入裂缝系统,堵塞渗流通道,结果导致气井产量偏低或没有产出。针对重晶石堵塞,运用螯合理论,通过室内实验和现场返排液离子分析表明,重晶石解堵剂能够溶解裂缝内的重晶石固相。该技术首次在X井试验,作业后气井日产气量由0.9×10~4m^3增加到5.2×10~4m^3,增产5.7倍,恢复了深度伤害气井的产能。该技术已推广应用在Y气田,增产效果显著,日产气量由26.2×10~4m^3提高到75.2×10~4m^3,增产近3倍。

In Keshen gasfield of Tarim Basin, due to high formation-pressure coefficient, a target layer was drilled by drilling fluid mixed with a large amount of barite for the purpose of weight increase. And the barite solids invaded into some developed fractures, plugging seepage channels or resulting in a low output even no production. So, based on the chelating theory, laboratory experiments and ion analysis of filed flowback fluid were carried out. Results show that the barite plugging remover may dissolve these solids among fractures. This technology of plugging removal was for the first time applied to X well, a severely damaged gas one, to recover its productivity. As a result, the daily gas production increased by 5.7 times, from 0.910 4 m^3 to 5.210 4 m^3.In addition, this technology with significant stimulation effect has been popularized in Y gasfield,and its daily production roughly tripled from 26.210 4 m^3 to 75.210 4 m^3.