小直径大砂量多层压裂技术在低渗透油田的应用

Application of Multi-layer Fracturing Technology with Small Diameter and Large Sand Volume in Low Permeability Oilfield

针对低渗透油田压裂选井、选层困难,压裂效果变差的问题,以提高剩余油措施挖潜为目标,对套损修复井、小井眼井等小直径井压裂技术进行了研究。研究得出:小直径封隔器、喷砂器与压裂管柱的配置适用套管内径大于Φ102mm、井温小于120℃的套管修复井及小井眼井的压裂,可一趟管柱坐压4层,并根据套损点位置限制设计了4种管柱结构,实现小直径大砂量多层压裂;套损修复井压裂后,初期平均单井日增液2.6t,日增油2.2t,增油强度1.3t/(d·m),含水下降26.0%;小井眼井压裂后,初期平均单井日增液1.8t,日增油1.6t,增油强度1.1t/(d·m),含水下降29.9%;套损修复井与小井眼井所在区域的剩余油分布较重复压裂、转向压裂井所在区域的剩余油更加丰富,措施潜力更为突出。小直径大砂量多层压裂工艺技术拓宽了压裂选井、选层的空间,为大庆长垣外围油田剩余油挖潜提供了有效的技术支撑。

Aiming at the problems like the difficult well and layer selection,and poor fracturing effect in low permeability oilfield,in or-der to improve the potential of remaining oil measures,the fracturing technology of small diameter wells such as casing damage repair wells and slim hole wells was studied.The research shows that the configuration of small-diameter packer,sand blaster and fracturing string is suitable for the fracturing of casing repair wells and slim hole wells with casing internal diameter greater thanΦ102 mm and with well temperature less than 120℃,which can set four layers of pipe string at a time.Then four pipe string structures are designed according to the limitation of the position of casing damage points so as to realize multi-layer fracturing with small diameter and large amount of sand.After fracturing of casing damage repair well,in the initial stage,the average daily fluid increase of single well is 2.6 t,the daily oil increase is 2.2 t,the oil increase intensity is 1.3 t/(d·m),and the water cut decreases by 26.0%;After fracturing of slim hole wells,in the initial stage,the average daily fluid increase of a single well is 1.8 t,the daily oil increase is 1.6 t,the oil increase intensity is 1.1 t/(d·m),and the water cut decreases by 29.9%;The residual oil distribution in the area where casing damage repair wells and slim hole wells are located is richer than that in the area where refracturing and steering fracturing wells are located,and the potential of mea-sures is more prominent.The multi-layer fracturing technology with small diameter and large amount of sand widens the space of well and layer selection,and provides effective technical support for tapping the remaining oil in the peripheral oilfields around Daqing placanticline.