Comparison of Fracturing Techniques for Unconventional Reservoirs

Due to their extremely low permeability, unconventional (UC) reservoirs such as tight sandstones, shale formations, and coal seams nearly all require hydraulic fracturing to maximize production. With marginal economics often at the forefront of the decision process to proceed with a field development project, successful fracture stimulation is critical for helping to de-risk these types of projects. Over the years the industry has used many different approaches in an effort to determine the “optimum” fracturing and completion design in different UC reservoirs. Using a variety of evaluation techniques that help to define success, one common theme emerges from the extensive amount of literature published: UC reservoirs respond most favourably to fracturing methods that are tailored to the specific reservoir conditions. This presentation will focus on some of the key factors that must be considered when designing hydraulic fracturing treatments for three different types of reservoirs; 1) low permeability sandstone formations, 2) shale reservoirs, and 3) coalbed methane (CBM) reservoirs, with a specific emphasis on comparing and contrasting the fracturing objectives between these different reservoir types.