The Impact of the Characteristics of Horizontal Wellbore and Hydraulic Fractures on the Reservoir Performance

Abstract

Hydraulic fracturing stimulation is a common practice in petroleum industry. The last two decades have witnessed great focusing on this process especially in North America and more or less attention in the European and Middle East oil fields. The process typically aims to increase the production recovery from oil and gas that can’t be produced by conventional techniques. It applies several hydraulic fractures along the horizontal wellbore that propagate to different zones in the formation.

The success of fracturing process is controlled by several parameters. Fracture length, height and conductivity are the three parameters that influence these successes. Proppant Number, defined as the fracture volume to the reservoir volume, was proposed to judge the fracturing process performance. Proppant Number might be expressed by fracture conductivity and the ratio of the fracture length to reservoir width or the horizontal penetration.

A new Proppant Number for multiple hydraulic fractures intersecting horizontal wellbore is presented in this paper. This number is determined from the volume of specific fracture and the volume of the drainage area surrounding the fracture. The new Proppant Number and the vertical penetration ratio, the ratio of the fracture height to the formation height, are two critical parameters affecting the productivity index of fractured formation.  A new model for the productivity index of finite reservoirs having multiple hydraulic fractures has been introduced. This model reflects the effects of the boundary dominated flow.

This paper shows that the productivity index increases with the increasing of Proppant Number and penetration ratio. The productivity index increases significantly for the increasing of Proppant Number when the number of fractures is small and slightly for large number of fractures. The change in productivity index with the penetration ratio can be noticed in short fracture lengths for large number of fractures and long fractures for small number of fractures.