水平井限流法压裂射孔方案设计方法研究

Design of perforation plan of limited-entry fracturing for horizontal wells

各种裂缝监测手段发现限流法压裂能够压开水平井的各个射孔段,但每个射孔段裂缝的扩展程度与预期存在明显差异,归结为现有布孔方式对储层的控制能力不强.建立一套指`导水平井限流法压裂设计的理论模型具有重要的实际意义.通过现场实验和理论研究,改进了喷嘴节流损失、井筒及孔眼摩阻的计算方法,在此基础上建立了水平井压裂多裂缝同时延伸的流量分配模型,与拟三维裂缝参数计算模型联立,可以实现对水平井限流法压裂射孔方案的设计.现场应用表明,该设计方法能得到预期的裂缝改造规模.

Limited-entry fracturing is a chief stimulation measures for horizontal wells in low permeability reservoirs,some monitoring results show that,all perforation intervals can be fractured by limited entry fracturing,but there is difference between the actual fracture geometry parameters and the expected parameters.It is because the perforation plan is lack of the control ability to reservoir.There is no a theoretical model to guide the design of the limited entry fracturing for horizontal wells.The calculation methods for throttle loss of nozzle and the friction pressure difference of holebore and perforation holes are modified by means of field tests and theoretical research.Based on these,a flow rate distribution model is established,and it can ensure all the fractures extend at the same time.The design plan for limited entry fracturing can be finished by combining the model with pseudo 3D fracture parameter calculating model.Field application shows that the design method for limited entry fracturing can achieve the expected fracture parameters.