Evaluating the Stimulation and Production Shadow in Drilled-Uncompleted (DUC) Wells: Drivers for Creating an Asset Optimization Strategy

Abstract

Dynamic geomechanics is a critical frac design element in the unconventional reservoirs. With the sudden downturn in oil prices in the recent times, operators in the unconventional reservoirs can no longer sustain factory mode of drilling and completing wells. North America has accumulated a huge inventory of Drilled but Uncompleted (DUC) wells in the recent past. Geomechanics of the reservoir has become increasingly more important to operate the DUC wells.

Optimizing completion designs require a determination of the altered stress state, dubbed as “Stimulation Shadow” or commonly known as Stress Shadow and also the “Production Shadow”. A streamlined workflow to account for reservoir heterogeneity, stimulation- and production-induced perturbation of the in-situ geomechanical properties enables achieving efficient and effective well configuration, completion strategy, pumping schedules and sequence of stimulation in DUC wells. The study amalgamates fracture modeling, reservoir simulation and finite-element geomechanical simulations on Eagle Ford and Permian DUC wells.

The goal is to simulate a variety of treatment designs and high grade completion options to maximize long term productivity of the well pad. While the Stimulation Shadow impacts subsequent stages pumped in the wells, the Production Shadow from parent well impacts hydraulic fracture geometry developed in the DUC well. Injection rates, stage and perf spacing impacts the Stimulation Shadow. Time and depletion are essential considerations to compute the production Shadow. It is concluded in the study that effective frac design requires an understanding of the geomechanics and reservoir neighborhood of the DUC well. Effective asset development strategy can be devised but as a more local solution - One size does not fit all. As an example, the study shows that the optimization and development strategy in Eagle Ford needs to be different than Permian basin. To truly characterize DUC frac design, it requires the high grading of multiple scenarios incorporating the effects of the Production Shadow.

The study presents the concept of “Stimulation and Production-shadow” as the intensity of geomechanical property change in four-dimensional space affecting DUC well’s performance and pad development strategy. This “model-to-design” journey couples the fracture stimulation on the wells with the stress field changes to optimize the well pad in a timeframe that can meet field operation completion schedules.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018