柴西地区低孔低渗储层改造配套技术及其应用

青海柴西地区储层为典型的低孔、低渗泥灰岩储层,储层中碳酸盐岩、碎屑岩、泥岩各占有基本相同的比例,对于这类既不同于纯碳酸盐岩也不同于纯砂岩的储层,在改造工艺上有很大难度。通过实施胶凝酸酸压技术、水力加砂+返排技术、醇酸酸化技术和油基压裂技术,在该地区各类探井上共进行措施改造43井次,其中酸化12井次、酸压20井次、加砂压裂11井次,从施工成功率来看,酸压、酸化施工的成功率远大于加砂压裂,现场施工参数和设计符合率在85%以上;施工效果显示,80%的井经过储层改造后产液量有所提高,液体的返排率平均为65%。

Systematic Techniques for Low Porosity and Low Permeability Reservoir Reconstruction and Their Application in Western Qaidam Basin

The reservoir in the western region of Qaidam Basin in Qinghai Province is a typical marlstone reservoir with low porosity and low permeability, in which carbonate rock, clastic rock and mudstone account for the same proportion respectively. It is difficult to improve such a kind of reservoir for its difference from pure carbonate rock reservoirs and pure sandstone rock reservoirs. By applying the techniques of gel acid fracturing, hydraulic sand and flowback, alkyd acidizing, and oil base fracturing, 43 times of technical transformation have been carried out in various exploration wells of the region including 12 times of acidizing, 20 times of acid fracturing, and 11 times of sand fracturing. The success rate of acid-fracturing and acidizing operation is far higher than that of sand fracturing, and the field operation parameter and the design coincidence rate are both kept at more than 85 percent. The results show that 80 percent of the exploration wells see an increasing fluid production based on the reservoir reconstruction, with the average fluid flowback rate being 65 percent.