Shale Reservoir-Centric Completions

Abstract

In North America, the transition from more conventional reservoirs into tight, basin-centered gas and now source shales has caused the industry to change the way reservoir performance is being assessed, measured, and documented. Historically in conventional reservoirs the reservoir quality was carefully examined on a well by well basis to determine reserves in place and exploitation plans. For unconventional reservoirs, however, the commercializing of such plays quickly became centered on horizontal drilling of long laterals combined with massive volume, high rate multi-stage hydraulic fracturing. In that environment, completion design and hydraulic fracturing have become more of a statistical process; additionally, incremental improvement and innovation are used to create a treatment schedule often replicated across an entire field without consideration of reservoir variability across a lateral. Based upon vertical well experience, the fracture initiation points can be carefully selected by identifying the locations within the well that are best to perforate. In a horizontal well, however, the location of the lateral defines the fracture initiation points anywhere along the well, so the stratigraphic location of the well lateral becomes critical in non-homogeneous shale plays. To address this, engineers and geoscientists can identify important parameters necessary for optimum completion design, and earth modelling can then be used as a tool to capture and model these properties across the asset making critical information available as needed for drilling, completion, and production operations.