川东北高温高压深井超深井酸压改造技术研究与应用

RESEARCH AND APPLICATION OF ACID FRACTURING TECHNOLOGY IN HTHP DEEP AND ULTRA -DEEP WELL OF NORTHEAST SICHUAN AREA

川东北地区大部分储层具有低孔、低渗、非均质强、高温、高压、含硫等特征,给酸压施工的安全性、成功率和有效率带来了极大的挑战。为此,在川东北地区高温高压深井、超深井酸压改造的难点分析基础上,以提高酸压施工的安全性为目的,进行了酸压管柱强度和抗H2S、CO2、酸液腐蚀及酸压施工质量控制技术研究;以提高酸压施工成功率为目的,开展了震荡挤酸、前置酸压、溴盐加重前置液酸压、高密度压裂液加重前置液酸压技术研究;以提高酸压施工有效率为目的,开展了酸液配方优选、酸压工艺优选及参数优化、残酸高效返排技术研究。形成了针对川东北地区高温高压深井、超深井的酸压改造工艺、配套技术及酸液配方体系,并在川东北地区共实施了5口井8层次的现场试验,施工成功率为100%,酸压有效率为80%,平均无阻流量由压前的1.09×104m3/d上升到124.27×104m3/d,取得了较好的增产效果。

There are the characteristics of low porosity, low permeability, strong anisotropism, high temperature, high pressure, sourness etc. in most of the reservoir in Northeast Sichuan, so, the acid fracturing operation is difficult in the area. In order to improve the safety of acid fracturing operation, the intensity, corrosion resistance of acid fracturing string and quality control technology of acid fracturing were studied. To improve the success ratio of acid fracturing operation, some corresponding acid fracturing technologies were researched such as shock squeeze acid, ahead acid fracturing, acid fracturing technology of high-density ahead fluid etc. To improve the effective rate of acid fracturing, the acid formula, acid fracturing technology and parameter were optimized, and residual acid flowback technology was also studied. The acid fracturing technology, corresponding supporting technology and acidizing fluid formula system suited for HTHP Deep and Ultra-deep Well of Northeast Sichuan Area were formed. Through field test in 5 wells, the results showed that the success ratio of the acid fracturing technology was 100% , effective rate was 80%, the average open-flow capacity was increased from 1.09×104m3/d to 124.27×104m3/d.