Abstract

During the development of unconventional oil and gas, multi -staged fracturing within horizontal well is used to create several fractures in one stage at one time. During the stimulation operation process, the present fracture will probably connect to the other established fractures in present stage or the former stage, which leads to hydraulic fractures difficult to effectively spread. A hydraulic fracture influences the extending direction of other fractures, namely, causing certain attraction or repulsion effect. In this paper, finite element calculation is made to simulate the interaction of fractures with different spacing and lengths. The results show that when the two fractures are extending in the same pace, the interaction will gradually change from repulsion to attraction with the spacing of two fractures getting closer. On the other hand, when the two fractures both are extending but not synchronously, both fractures will curve towards the side of the shorter fracture if the spacing is relatively small compared to the fractures’ length. In addition, an already formed fracture will attract a newborn fracture at a short distance, but repel it at a longer distance. Based on the calculation above, guidance can be provided for optimization of fracture distributions for multi -staged fracturing treatments.

1. INTRODUCTION

During the development of unconventional oil and gas, multi -staged fracturing within horizontal well is used to create several fractures in one stage at one time. During the stimulation operation process, the present fracture will probably connect to the other established fractures in present stage or the former stage, which leads to hydraulic fractures difficult to effectively spread. A hydraulic fracture influences the extending direction of other fractures, namely, causing certain attraction or repulsion effect. In this paper, finite element calculation is made to simulate the interaction of fractures with different spacing and lengths. The results show that when the two fractures are extending in the same pace, the interaction will gradually change from repulsion to attraction with the spacing of two fractures getting closer. On the other hand, when the two fractures both are extending but not synchronously, both fractures will curve towards the side of the shorter fracture if the spacing is relatively small compared to the fractures’ length. In addition, an already formed fracture will attract a newborn fracture at a short distance, but repel it at a longer distance. Based on the calculation above, guidance can be provided for optimization of fracture distributions for multi -staged fracturing treatments.

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