提高改造体积的新裂缝转向压裂技术及其应用

Study and application of new in-fissure fracturing technique for improving stimulated reservoir volume

体积改造技术带动了非常规致密气、页岩气和煤层气等油气资源开发的迅猛发展,对于低孔、低渗透基质的碎屑岩储层,探索提高其改造效果的体积改造技术具有重要意义。为此,在转向压裂和缝网压裂的基础上,通过力学分析和流——固耦合渗流模型,对压裂施工中的应力场进行研究,分析了地层2个水平主应力的变化。采用强制闭合、快速返排、多次加砂的工艺,实现地层2个水平应力场的短期变化,形成了在短期内实现提高改造体积的新裂缝转向压裂技术,与常规技术相比,新技术既简单可靠,又能有效降低施工风险。该技术在华北、长庆和吉林油区的低渗透油田应用10余井次,其初期产油量比常规技术提高1～2倍,稳产期延长6个月以上。

The fracturing technique improving stimulated reservoir volume (SRV) brings the soaring development in unconventional gas and oil at home and abroad, it has an important influence for low permeability and low porosity sandstone reservoir. In order to improve the output of post-fracturing, this paper, based on the theory of in-fissure fracturing and network fracturing and through the mechanics and fluid and solid coupling analysis, analyzes two horizontal stresses. Using force closure, and quickly flow-back and multiple treatment, the horizontal stress difference is decreased so as to divert the fracture in short time. Compared with former technique,the new method has the merits of simple and low risk, particular to the high temperature, complicated and difficult treated wells. It can improve the treatment and performance, meanwhile, it extends the method of improving SRV.