苏里格气田水平井常规压裂与体积压裂数值模拟

Numerical Simulation of Horizontal Gas Well Conventional Fracturing and Volume Fracturing in Sulige Gas Field

为实现苏里格气田水平井高效开发,提高气藏最终采收率,根据体积压裂的原理,对苏里格气田水平井体积压裂的适用性进行分析研究。通过数值模拟方法,对水平井采用常规压裂(3段),体积压裂(3段2簇、3段3簇、3段4簇和3段5簇)2种压裂改造方式进行模拟对比。结果表明,苏里格气田的储层具有天然微裂缝部分发育、石英含量相对高及渗透率低等因素,实施体积压裂的条件能基本满足;根据气藏特点在常规压裂和体积压裂模型中引入矩形不渗透岩性边界,该类边界极大减慢气体流向裂缝的渗流速度;体积压裂同一配产量不同簇数方案的稳产期均较常规压裂的长,不同稳产期末、10年末,体积压裂采出程度随簇数增加而增加,配产量为8×104 m3时,体积压裂与常规压裂相比优势更明显;体积压裂令缝网内压力波及均匀,避免常规单一裂缝开采时间过长造成的缝周低压现象。

In order to realize the efficient development for horizontal well in Sulige Gas Field and improve the ultimate gas recovery,the applicability of volume fracturing horizontal well were analyzed based on the mechanism of volume fracturing.By the method of numerical simulation of horizontal well,the conventional fracturing （3 Section）and volume fracturing （3 Section 2 clusters,3 Section 3 clusters,3 Section 4 clusters and 3 Section 5 clusters）were simulated compared two methods for fracturing.The results show that it has a relatively high content of quartz, natural micro-fracture development, low permeability in Sulige Gas Field,which can meet the basic conditions of implementing volume fracturing.According to the characteristic of gas reservoir,the rectangular impermeable lithological boundary were introduced to the conventional fracturing and volume fracturing model,and the flow velocity of gas to direction of crack was greatly slowed down.The stable period was longer than conventional fracturing,when volume fracturing was with same volume production and different number of the cluster scheme.At different stable final or at the end of 10,the volume of the fracturing degree of recovery increased with the increasing of clustersnumber.When production was 80 000 m3 ,volume fracturing advantages was more obvious compared with conventional fracturing.Pressure spread was made uniform by volume fracturing in fracture network,which can avoid the low pressure phenomenon caused by long time exploring.