临兴地区盒八段砂岩裂缝发育特征及其对压裂效果的影响

Fracture characteristics of the 8th member of Shihezi formation in Linxing Area and its influence on fracturing effect

为了深入研究临兴地区盒八段砂岩天然裂缝对压裂效果的影响,基于野外节理观测和成像测井数据对临兴地区天然裂缝发育特征进行精细描述,并利用微地震技术对压裂裂缝进行动态监测。结果表明:①临兴地区盒八段天然裂缝以剪节理为主,节理发育优势方向为NNW、NWW、NNE、NEE,天然裂缝倾角大、数量少且集中发育。②压裂效果穿越型控制类型最差,沟通型较好,俘获型最好;较小的逼近角及水平主应力差利于天然裂缝的开启,当压裂区域水平主应力差较大时,应选择较小的逼近角,以沟通型控制类型压裂为宜;当压裂区域水平主应力差较小时,应适当增大逼近角,以俘获型控制类型压裂效果最佳。研究结果为致密砂岩水力压裂方案设计提供了理论基础。

In order to study the influence of natural fractures on fracturing effect of the 8th member of Shihezi formation in Linxing area,the characteristics of natural fractures in Linxing area are described based on field joint observation and imaging logging data.At the same time,the micro seismic dynamic monitoring method is used to monitor the process of the formation of the fracturing fractures in the 8th member of Shihezi formation in Linxing area.The results show that:①The natural fractures of 8th member of Shihezi formation in Linxing area are mainly concentrated shear joints with large dip angle,but the total number of natural fractures is less,and the dominant directions of joint are NNW,NWW,NNE and NEE.②The fracturing effect of crossing control type is the worst,the communication type is better,and the capture type is the best.Smaller approach angle and horizontal principal stress difference are beneficial to the opening of natural fractures.When the level of horizontal principal stress difference in the fracturing area is higher,It s better to adopt a smaller approach angle for fracturing,and this type control of fracturing is communication.When the level of horizontal principal stress difference in the fracturing area is smaller.It s better to adopt a bigger approach angle for fracturing,and this type control of fracturing is capture control type.The results provide a theoretical basis for hydraulic fracturing scheme design of tight sandstone.