How to Decide Between Horizontal Transverse, Horizontal Longitudinal and Vertical Fractured Completion

Abstract

Abstract Augmented by the recent activities in shale gas, hydraulic fracturing of horizontal wells has become increasingly popular, although the technology has existed for over 20 years. The success in shale gas activities and advances in completion technology may have generated the false impression that fractured horizontal wells may be successfully applied to almost any formation. Although the very low-permeability shale gas formations in the cost-controlled environment of North America may have justifiably made multiple-fractured horizontal wells the completion of choice, many do not realize that there are circumstances where a simple vertical fractured well may significantly outperform a fractured horizontal well. Because it is usually too late to change completion type once the wellbore has been drilled, it is vital that the selection of type of fractured completion to be used is considered during initial well and field development planning. This paper will discuss the production mechanisms from horizontal transverse, horizontal longitudinal and vertical fractured wellbores. Calculations of the incremental performance of each configuration are done for both oil and gas wells. There are physical and economic limits and criteria. For example, for gas wells in reservoirs above 0.5 md, there is an unacceptable reduction in the performance of each transverse fracture because of enhanced turbulence effects. There are also economic criteria for selecting which type of completion is the optimum choice. We look at a range of reservoir and proppant pack permeabilities and discuss the optimization of fracture geometry. The paper not only delineates areas of indicated application of each well completion but it highlights the importance of considering the hydraulic fracturing process from the very start of wellbore planning. The processes involved in planning a wellbore for efficient decision making and maximum flexibility of choice are also described.