A fracture starting from one perforation might fail to link-up with adjacent perforations and the fracture may break up into multiple fractures. Failure to link-up neighbouring perforations and the occurrence of multiple fractures reduce the communication between a propped fracture and the well.

Many experiments have been performed to study the near wellbore fracture geometry. They give a good insight in the impact of the treatment parameters on the near wellbore fracture geometry. However, they urge the need for a detailed numerical study of the first stages of fracture propagation as the processes that cause the near wellbore fracture geometry are not well understood.

The stress distribution on the wall of the perforations plays a decisive role as to where fractures initiate. In this paper we discuss the stress distribution around perforations around an arbitrary oriented borehole. We will present the results of an analytical model and a numerical model. Although the calculations give a fairly good description of the stresses near the wall of the perforations they do not always reproduce the site from which the major fractures initiate and give no explanation for the existence of multiple fractures.

This paper discusses numerical fracture propagation simulations from a perforated deviated borehole. We discuss fracture propagation as function of in-situ stresses, pressure, and perforation orientation. We will also discuss the link-up of starter fractures from adjacent perforations. The simulations provide a way to get a better insight in the processes that lead to the near wellbore fracture geometry. With this insight the fracturing treatments can be optimised and the formation of multiple fractures can be limited.

You can access this article if you purchase or spend a download.