固井滑套端口参数对压裂影响的试验研究及模拟分析

为了解固井滑套端口参数对裂缝起裂压力和裂缝形态的影响,利用全尺寸水力压裂模拟试验系统,进行了φ168.3 mm固井滑套不同类型端口下的滑套固井地面压裂试验,采用有限元数值模拟方法对试验结果进行了分析.结果表明:在端口面积相同的条件下,槽型端口与翼型端口的起裂压力相差较小;随着端口角度的增大,起裂压力呈升高的趋势;端口长度与端口数量对起裂压力的影响较大,随端口长度的增大及端口数量的增多,起裂压力降低;翼型端口及角度为0°槽型端口的试验样本,压裂后形成了较宽的单一对称裂缝,带角度端口的试验样本破裂后形成的裂缝较为复杂.研究表明,端口角度及端口长度与起裂压力分别满足二次函数关系;端口数量与起裂压力呈线性关系.研究结果可为固井滑套端口参数的优选提供理论依据及参考. 

Testing and Simulating the Effect on Fracturing of Port Parameters of a Cemented Sliding Sleeve

In order to understand the effect of port parameters on fracture initiation pressure and fracture geometry, a fracturing test with φ168.3 mm cemented sliding sleeve that has different types of ports was conducted by theoretical and experimental studies. A ground test of cemented sliding-sleeve fracturing was carried out by use of full-size hydraulic fracturing simulation system, and the test result has been analyzed by using a finite element numerical simulation (FEM). The results show that fracture initiation pressure difference between slot-type port and wing-type port is smaller. The fracture initiation pressure rises with increase of the port angle. The length and quantity of the ports have a large effect on the fracture initiation pressure and the fracture initiation pressure decreases with increase of the port quantity and tube length. A test sample with a wing-type port and 0° slot-type port can form a single symmetric crack after fracturing, and the test sample of port with an angle can form a more complex one. The research results show that the port angle and tube length follow a quadric function relationship with the fracture initiation pressure, and the port quantity follows a linear relationship with the fracture initiation pressure. The results provide a basis and reference for optimizing the port parameters of φ168.3 mm cemented sliding-sleeve and other sleeves.