不动管柱水力喷射逐层压裂技术

Zone by zone hydrojet fracturing without pulling strings

水力喷射压裂是目前先进的分层、分段压裂工艺之一,但由于该工艺要靠井下作业改变其喷射位置才能实现多层压裂,致使工艺推广受到制约。为此,在水力喷射压裂前期研究成果的基础上,通过对喷嘴个数和直径的优化研究、井下压力节点分析,从油管排量与泵压的关系入手,建立了水力喷射无因次特性曲线,探索了环空井底压力的大小计算方法,解决了环空补液量与排量的关系等设计难题,在国内首次提出了完井不动管柱条件下的水力喷射逐层压裂设计方法。同时,配套研制了适用于178mm(215.9mm裸眼)、139.7mm(152.4mm裸眼)和127mm套管的3种规格一趟管柱作业4层的滑套式喷射器。通过现场4口井共13层的作业,结果证明不动管柱水力喷射逐层压裂技术发展和完善了水力喷射压裂工艺,不但实现了射孔、压裂、生产联作,还为合层开采提供了条件。

Hydrojet Fracturing is one of the advanced techniques for separating layers or multi-interval fracturing.However,this technique can achieve multi-layer fracturing only when the down-hole operations are carried out,which restrains its wide application on fields.Based on the current research findings on the hydrojet fracturing,the number of muzzles and their radius are optimized and the down-hole pressure nodes are analyzed.Starting from the relationship between the tubing discharge rate and the pump pressure,the dimensionless characteristic curve on hydrojet is drawn,the calculation method for the annulus bottomhole pressure is explored,the design problems such as determining the relation of the annulus supplementary liquid and the discharge rate are solved,the design techniques for hydrojet separating layers fracturing without pulling strings are proposed first in China.Meanwhile,a sliding jet gun is developed and configured for the casing pipes of 3 specifications,i.e.,Φ178 mm(Φ215.9 mm open hole),Φ139.7 mm(Φ152.4 mm open hole),and 127 mm,which realizes 4-layer fracturing with the pipe string operation for only once.The results from the field operations on 13 layers of 4 wells show that the zone by zone hydrojet fracturing technology without pulling strings is one of the developed and improved hydrojet fracturing techniques.Moreover,not only can it achieve the interactions of perforation,fracturing and production but also provide good conditions for the commingled production.