二氧化碳前置蓄能压裂在中深层低渗稠油中的应用

Research and Application for Carbon Dioxide Precharged Volume Fracturing to Low Permeability Heavy Oil in Medium and Deep Formation

针对准噶尔盆地中深层低渗稠油的开发难点,将体积压裂与CO_(2)驱油技术有机结合,开展CO_(2)前置蓄能压裂提产机理研究及开发关键参数优化。实验表明,CO_(2)前置蓄能压裂有效增加了可流动原油体积,主要的驱油机理为“CO_(2)基质抽提、原油溶胀降黏、裂缝导流”。以准噶尔盆地J井区为例,开展CO_(2)前置蓄能压裂提产试验,与常规压裂相比,投产初期单井日产油量相当,但试验井压力保持程度更高,稳产能力更好,目前累计产油是常规压裂井的1.14倍,预计采收率可以提高3%,为新疆油田数亿吨难动用储量有效开发提供技术支持。

In order to solve the difficulties in the development of medium and deep heavy oil in the Junggar Basin,combining volume fracturing with carbon dioxide oil displacement technique and the research of carbon dioxide precharged volume fracturing to increase production and optimize key develop parameters was carried out.The result shows that the technique can effectively improve the volume of flowing crude oil.Its main mechanisms is Matrix extraction,crude oil swelling and viscosity reduction,and fracture diversion.Taking Well Block J in the Junggar Basin as an example,conduct carbon dioxide pre-storage fracturing and production improvement tests,comparing with conventional fracturing operation,the per oil production is almost same in early production,but the pressure of the test well keep more stable with better stable production capacity.At the moment,the cumulative oil production is 1.14 times that of conventional fracturing operation,and expected recovery rate can increase by 3%.The technique provides technology support for hundreds of millions of tons of reserves in Xinjiang oilfield which is difficult to be exploited.