A Technical and Economic Study of Completion Techniques in Five Emerging US Gas Shales

Abstract

AbstractWith the increased demand for energy and the declining conventional hydrocarbons worldwide, energy companies are turning to unconventional resources, such as shale gas. With over 2, 000 TCF gas in place indentified in just 5 shale gas plays in the United States, shale gas formations are now the number one targets for exploration drilling. Furthermore, there are still many more major shale gas plays and basins waiting to be explored, evaluated and developed. Because of the extremely low permeability of most shale formations, it is essential to select the appropriate completion techniques for shale gas reservoirs. There are very few papers in the petroleum literature that provide a logical method to select completion techniques for given shale gas reservoir conditions. There are papers discussing successful completion techniques that seem to work for a specific shale. We have used many of these SPE papers to help define "best-practices" in completing shale gas reservoirs. We then developed logic to determine the best practice on completing shale gas reservoirs as a function of reservoir conditions. In this paper, we will specifically cover the logic we have developed for choosing completion techniques on shale gas reservoirs.First, we performed a literature review on the five basins as well as on all shale gas plays in the U.S. to determine the best practices in shale gas completion techniques in fluctuating price environments and identify key geologic parameters that affect overall well performance. From our literature review, we identified seven pertinent geologic parameters that influence shale gas completion practices. Next, we identified different completion trends in the industry for different geologic settings. Subsequently, we generated an economic model and performed sensitivity analysis to determine optimal completions for each gas shale basin. Based on these economic models, we developed the decision flowcharts to select completion techniques. Finally, we programmed the flowchart and we call this program as Shale Gas Advisor. This program can be used to determine optimum completion best practices for not only the five gas shale basins discussed, but also, for gas shale plays that have similar geologic attributes. We validated the program with published case histories in the SPE literature.