Pilot test of efficient acidizing technology in complex sandstone reservoir

the yield-increasing effect of sand fracturing and conventional acidizing in Xujiahe complex sandstone reservoir in western sichuan because the burial depth of the reservoir is deep and the geological condition is complicated. And it leads to abundant natural gas resources can not be explored effectively. The key points during the sand fracturing and conventional acid treatment were analyzed in this article, combining the output increasing mechanism of sandstone acidizing with the geological features, a new type highly effective acid system is optimized. The acid system has low acidizing dissolution rate for core framework (about two percent), high acidizing solution rate for drilling mud (about fifteen percent), and could preferentially prevent the acidification deposition with good retarded ability. The labs experiments and field application indicated that the optimal new type acid liquor can remove pollution in the procedure of well drilling and completion effectively, corroding and communicating the rock pore throat and micro-cracks. The new system is distinctly superior and has remarkable effect comparing to the general acid system. The successful application provides reference for similar sandstone reservoir stimulation.