Impact of Completion Design on Unconventional Horizontal Well Performance

Abstract

Unconventional resource plays involve the development of some unusual reservoirs such as shale with effective permeability in the nano-Darcy range. Reservoir development of these resource plays requires drilling horizontal well with multi-stage hydraulic fracturing. Completion design that incorporates geological constraints is often the critical step as it dictates the drainage volume and well spacing to decide how the play will be developed in the future. There are numerous variables that dictate the choice of potential completion design and its impact on well performance. Understanding these key variables that control the outcome of massive hydraulic fracturing in a horizontal well is the need of the hour. This paper explores how readily available fracture pump data, pressure and rate data can be utilized to estimate and understand the unknowns involved in the completion and the reservoir parameters. In this paper, we compared wide range of datasets from multiple shale plays in North America to analyze the effect of well spacing, wellbore geometry, fracture spacing, fracture proppant to liquid ratio, and completion inefficiency on well performance. The results show how the changes in these parameters can be correlated to understand the overall potential of the well. These results can be used to build a knowledge base which can guide us towards best field development planning by reducing the amount of experimentation and thus help in cost saving. Introduction Completion parameters can have a significant impact on horizontal well performance in unconventional plays. Understanding completion effectiveness of these wells is always a challenge. Effective drilling and completing well requires understanding of the reservoir and rock quality. Reservoir quality parameters define hydrocarbon accumulation and flow properties. Rock quality defines the mechanical properties that dictate how rocks fracture. Reservoir quality is estimated from permeability (k), original gas in place (OGIP), porosity (φ) and water saturation (Sw). Rock mechanical properties can be estimated from rock mineralogy, Young’s moduli (Y) and Poisson’s ratio (PR). Jayakumar et al. (2013) studied the effect of completion parameters such as amount of proppant pumped during stimulation, pumping rate, lateral landing and wellbore placement on well performance. We studied other completion parameters such as well spacing, wellbore geometry, fracture spacing, fracture proppant to fluid ratio and other completion inefficiencies. Researchers have tried to understand the impact reservoir and rock quality on the overall well performance. Agarwal et al. (2012) has addressed some of the widely used completion techniques in five different shale plays from North America. Shebl et al. (2012) showed the effect of various rock and completion properties on vertical fracture growth and well performance. Shebl et al. (2013) talked about the importance of lateral placement in a shale reservoir based on the reservoir and rock properties of a nearby vertical well. Hashmy et al. (2012) identified sweet spots for stimulation based on the reservoir and rock properties of the horizontal well. Bartuska et al. (2012) showed how proppant and fluid tracers can be useful to answer several completion design questions. Xie et al. (2012), Bai (2012) URTeC 2013 Page 1329