葡萄花外围薄差储层大排量压裂技术探索与实践

Exploration and Practice of Large-displacement Fracturing Technology in the Thin-Poor Reservoirs in the Periphery of Putaohua

葡萄花油田进入开发后期,高含水井及重复压裂井逐年增多,具有改造潜力且发育较好的葡萄花储层不断减少,薄差储层成为油田后续措施改造的重点。受此类储层物性及自身条件限制,采用常规压裂改造工艺增油效果不理想。葡萄花外围薄差储层主要分布于敖南及台肇区块,在这两个区块开展了多层段大排量压裂现场试验6口井,施工排量达到4.0~7.5m^3/min,平均单井压裂2.1个层段,单层有效厚度0.5m,平均单层施工液量115m^3,单层加砂9m^3。试验初期,平均单井产液强度1.83t/d·m,产油强度1.83t/d·m;与同区块储层条件相近的11口压裂投产井相比,初期产油增加1.7t/d,产液强度增加0.68t/d·m,平均单井年累计多产油207.3t。现场监测表明,大排量压裂在葡萄花外围薄差储层上产生了主缝与微缝共同存在的复杂裂缝网络,实现了提高裂缝改造体积的目的。

Putaohua oilfield has entered the later development stage with increasing high-water-cut wells and repetitive fracturing wells year by year.The reservoirs with reconstruction potential and better development have decreased gradually and the thin-poor reservoirs are becoming the focus of the redevelopment of the oilfield.The stimulation effect is not ideal by conventional fracturing for the physical property and the condi- tions itself of the thin,poor reservoirs.The thin-poor reservoirs in the periphery of Putaohua distribute in Ao- nan and Taizhao block mainly.Large-displacement fracturing for multi-layer was carried out in 6 wells of the two blocks.The displacement in the field is up to 4.0 to 7.5m3/min and average fracturing layers are 2.1 for single well.Effective thickness for single layer is 0.5m,liquid production for single layer is l15m3 and sand- ing for single layer is 9m3.At the initial stage of the experiment,average fluid producing intensity in single well is 1.83t/d＇m,and oil producing intensity is 1.83t/d.m.Compared with 11 fracturing wells for production with similar reservoir conditions in the same block,the initial oil production increased by 1.7t/d,and the flu- id producing intensity increased by 0.68t/d·m.Average cumulative oil production in single well increased by 207.3t.Field monitoring shows that the large-displacement fracturing results in the complex fracture network of the co-exist of main fracture and micro-fracture in the thin-poor reservoirs in the periphery of Putaohua, and the aim of improving the stimulated reservoir volume by the fracture was achieved.