低产油气井强制裂缝转向重复压裂技术

Re-Fracturing Technique Using Forced Fracture Re-Orientation of Low Production Oil and Gas Wells

为提高低产油气井产能和延缓压裂后产量递减速度,在分析重复压裂技术原理和存在问题的基础上,提出了增大改造体积的强制裂缝转向重复压裂技术。首先计算满足裂缝转向所需的限定最高压力,然后利用研制的水溶性转向剂在原有裂缝中形成憋压,直至压力达到新裂缝开启的压力条件,从而实现强制裂缝转向、增大压裂改造体积的目的。该技术在DJ气田3口井进行了现场试验,加入转向剂后井口压力平均上升幅度达到12.8MPa,压裂后平均单井产气量增加3 000m^3/d。研究结果表明,强制裂缝转向重复压裂技术具有转向成功率高、转向剂用量少和适用性强等技术优势,增产效果显著,为低产油气井重复改造提供了新的技术手段。

To improve the productivity of low production gas and oil wells and to delay or mitigate the post-fracturing production decline rate,a re-fracturing technique using forced fracture re-orientation to enlarge the stimulated volume was proposed based on the analysis of the principle of the re-fracturing technique and the existing problems.By first calculating the maximum pressure for re-orientation,the newlyconstituted water soluble diverting agent was applied to build the pressure in original fractures until the pressure was high enough to create a new fracture,thereby accomplishing the objective to forcibly divert fractures and enlarge fractured volume.This technique has been put into practice in three wells of the DJ Gasfield,resulting in the average wellhead pressure increasing up to 12.8 MPa and the average single-well gas production increasing by 3 000 m^3/d after the adding the diverting agent.The research and application results indicated that this re-fracturing technique using forced fracture re-orientation has the technical advantages such as achieving a high success rate of re-orientation operation,reducing the amount of diverting agent used,being suitable for extensive applications,with an obvious production increase.Thus the re-fracture technique using forced fracture re-orientation provides a new technical method in restimulation of low production wells.