低渗砂泥交互油藏压裂多裂缝扩展规律

Multi-fractures propagation law of low permeability sand shale interbed 
oil reservoirs fracturing

宋丽阳 王纪伟 刘长印 孙志宇 田宝刚

中国石化石油勘探开发研究院，北京 102206 中国石化中原石油工程有限公司井下特种作业公司，河南 濮阳 457164

Petroleum Exploration and Development Research Institute, SINOPEC, Beijing 102206, China Downhole Special Service Company, Zhongyuan Petroleum Engineering Co., Ltd., SINOPEC, Puyang 457164，China

针对低渗砂泥交互储层水平井多段多簇压裂裂缝扩展特征复杂的问题，建立多裂缝扩展数值模型，研究不同储隔层应力差、隔层厚度、施工参数条件下压裂裂缝的扩展规律。研究表明：中低储隔层应力差、薄泥质隔层条件下，裂缝穿透隔层扩展，中间裂缝在应力干扰下纵向大幅扩展；高应力差条件下，缝高扩展受到抑制，中间缝长低于两侧缝长；高施工排量条件下，裂缝在中低储隔层应力差储层上下突进幅度增大；高黏压裂液可导致中低应力差储层压裂裂缝上下突进幅度增大，缝高与缝宽明显增加。以X低渗砂泥交互油藏区块水平井为例，开展模拟研究，分析储隔层应力差、隔层厚度、施工排量、压裂液黏度对缝高扩展影响。对于低应力差、低隔层厚度储层，采用低排量、低黏压裂液降低穿层风险。

To study the complex characteristics of the hydraulic fracture propagation law during multi-staged cluster horizontal well fracturing in low permeability sand shale interbed oil reservoirs, a numerical model of multi-fracture propagation was established to study the fracture propagation law of fracturing under different reservoir-barrier stress difference, barrier thickness and construction parameters. The results show that under the condition of low and medium reservoir-barrier stress difference and thin mud barrier layer, the fractures penetrate the barrier layer and propagate, and the middle fractures propagate greatly in the longitudinal direction under the stress disturbance. Under high stress difference, fracture height expansion is inhibited, and the length of the middle fractures is lower than the fractures at two sides. Under the condition of high injection rate, the fracture breakthrough increases in the reservoir with middle and low reservoir-barrier stress difference. The use of high viscosity fracturing fluid can lead to the increase of fracturing breakthrough, and the fracture height and width increase obviously. Taking horizontal wells in the X low permeability sand shale interbed oil reservoir as an example to carry out simulation study and analyze the influence of reservoir stress difference, barrier thickness, injection rate and fracturing fluid viscosity on fracture height propagation. It is suggested to reduce the risk of cross-layer by using low injection rate and low viscosity fractuing fluid for low stress difference and low barrier thickness reservoirs.

10.6056/dkyqt202301003