07122-43

Primary Performer
University of Tulsa (TU), Tulsa, OK 74104

Additional Participants
Texas A&M University, College Station, TX 77843
Devon Energy, Oklahoma City, OK 73102

Abstract
One of the most important challenges the operators of tight gas reservoirs face is optimizing infill well locations. Unlike conventional reservoirs, optimization of infill well locations in tight gas reservoirs is significantly difficult for the following reasons:

• The tight gas reservoirs show significant variation in reservoir properties and lack of spatial continuity. It is difficult to determine the contributions from a new well due to acceleration of production and incremental addition due to connection of new drainage volumes.
• These sands, on a gross basis, tend to be quite thick. During the upscaling of fine-scale models for simulation purposes, the sands will create appearance of connectivity which does not exist in the finescale model.
• The distinction between static and dynamic connectivities needs to be recognized. Sands which appear continuous may not help production due to very low permeability and convoluted flow patterns resulting in lack of dynamic continuity.
• The orientation of hydraulic fractures can make a difference in optimizing well spacing.

The proposed project, Optimization of Infill Well Locations in Wamsutter Field, addresses specific issues in the Wamsutter gas field, one of the largest gas fields in the Rocky Mountain region. The solutions proposed here can be used in other similar tight gas reservoirs.

We use a combination of streamline simulation and modified flow simulation methods to properly account for the dynamic connectivity in the reservoir. After generating the reservoir descriptions, through the use of streamline (time of flight) concept, we will determine the connected volume to a single well. We will ensure consistency between the time of flight and the EUR. We will then remove the unconnected volume during the flow simulation, and “add” new connected volume as new wells are drilled. History matching of the earlier production data will be based on fracture orientation and its conductivity. Using the proposed approach, we will be able to address the following:

• Contribution to well performance due to acceleration and incremental production due to connected volumes.
• “Sweet spots” within the representative areas of the Wamsutter field where infill drilling on 40-acre spacing is economically justified.
• Effect of fracture orientation on the optimal well spacing.

Principal Investigator Mohan Kelkar