基于给定参数的水力裂缝与天然裂缝相互作用结果的预测准则

水力裂缝（HF）和天然裂缝（NF）之间的相互作用在压裂裂缝性储层中扮演着重要角色，并可能导致复杂的裂缝网络。该文基于断裂力学理论提出了一个基于给定参数的显式表达式准则。在进行数值模拟、实验或现场施工之前，根据输入参数，应用本准则预测HF遇到NF后的穿透、打开或滑移行为，以及评估已有的水力压裂试验结果。根据准则可知，在高地应力差和高交汇角下，HF容易穿透NF；在低地应力差和低交汇角下，HF容易打开NF；在适当的应力差和交汇角度以及摩擦系数条件下，NF会在HF的作用下发生剪切滑移。高的岩石断裂韧性和短的HF长度（水平井筒到NF的距离）也会导致HF打开NF。相比其他隐式表达式或通过计算程序给出的准则，该文提出的准则只依赖于外部输入参数，具有显式表达方式，方便压裂实验和工程应用。

A PREDICTION CRITERION FOR THE INTERACTION BETWEEN HYDRAULIC FRACTURES AND NATURAL FRACTURES BASED ON GIVEN PARAMETERS

The interaction between hydraulic fracture (HF) and natural fracture (NF) plays a significant role in hydraulic fracturing and can lead to complex fracture networks. Based on the theory of fracture mechanics, this paper presents an explicit expression criterion of given parameters. This criterion is intended to predict the infiltration, openness and slippage of HF after it encounters NF, and to assess the results of existing hydraulic fracturing tests prior to conducting numerical simulations, experiments or field treatments. The criterion shows that HFs tend to penetrate NFs only under high differential horizontal stresses and high approach angles, while open NFs under lower differential horizontal stresses and lower approach angles. When the differential horizontal stresses, intersection angle and friction coefficient are appropriate, NFs will slip due to shear. In addition, high fracture toughness of rock and short HF length (distance between wellbore and NF) can also cause HF to open NF. Comparing with other implicit expressions or those given by computational programs, the proposed criterion relies only on external parameters, with explicit expressions to facilitate fracturing experiments and engineering applications.