致密储层水平井压裂-补能-驱油一体化重复改造技术

Integrated re-stimulating technology of fracturing-replenishment-displacement of horizontal wells in tight reservoirs

白晓虎 齐银 何善斌 朱西柱 侯正孝 张岩

中国石油长庆油田分公司油气工艺研究院，陕西 西安 710018 低渗透油气田开发国家工程重点实验室，陕西 西安 710018 中国石油长庆油田分公司第十采油厂，甘肃 庆阳 745000

Oil & Gas Technology Research Institute, Changqing Oilfield Company, PetroChina, Xi′an 710018, China National Engineering Lab for Exploration and Development of Low-Permeability Oil & Gas Field, Xi′an 710018, China No.10 Oil Production Plant, Changqing Oilfield Company, PetroChina, Qiangyang 745000, China

受储层致密低压、长期注采条件下有效驱替系统难以建立等因素影响，鄂尔多斯盆地部分水平井产量递减大，采油速度和累计采出程度较低。为此，基于水平井压力场及应力场分布规律，集成体积改造、补充能量、渗吸驱油一体化重复改造技术优化设计模式，配套实施了机械封隔与动态暂堵相结合的大排量高效分段复压工艺及管柱。测试分析表明，水平井重复压裂储层改造体积达到初次压裂的2倍以上，裂缝复杂指数达到新井压裂时的1.3倍，地层压力保持水平由75%提高至120%。试验井复压后单井产油量由2 t以下提高至10~15 t，自喷期达到3个月以上，生产1 a后平均产油量仍达到10~12 t/d，采油速度由0.22%提升至1.05%，预测最终累计产油量可提高1倍以上。该技术对其他非常规储层提高水平井老井产量及最终采出程度有一定的借鉴。

Affected by tight reservoir, low pressure and difficulty in establishing long-term injection-production displacement, the production of some horizontal wells in the Ordos Basin is decreasing gradually, and the oil recovery rate and cumulative recovery are low. Based on the distribution of pressure field and stress field of horizontal wells, the integrated optimization design mode which consist of reservoir volume stimulation, replenishing formation energy and imbibing displacement is carried out, and the large displacement and high efficiency segmented refracturing technology and string with a combination of mechanical packer and dynamic temporary plugging are matched. The test analysis shows that the volume of the re-fracturing reservoir in horizontal wells is more than 2 times that of the initial fracturing, the fracture complex index FCI is 1.3 times that of the new wells, and the formation pressure maintenance level is increased from 75% to 120%. After refracturing of the test wells, the single-well oil production increased from less than 2 tons per day to 10—15 tons per day, the flowing period reached more than 3 months, the average production still reached 10—12 tons per day after one year of production, and the oil recovery rate was increased from 0.22% to 1.05%. The predicted cumulative production can be more than doubled. This technology has some reference for other unconventional reservoirs to improve the production of old horizontal wells and the final recovery.

10.6056/dkyqt202101011