Abstract

The potential oil resources and the unique nature of the Delaware Basin (West Texas and Southern New Mexico (USA)) make commercial development in this play attractive as well as challenging. Establishing an optimal well spacing has been recognized by operators in this region as one of the key challenges — especially when balancing between the technical aspects of optimal hydrocarbon recovery and the economic aspects of optimal financial metrics. It is of critical importance to first understand the fundamental nature of the Wolfcamp formation in the Delaware Basin and in particular, what makes this formation so unique, before an attempt can be made to tackle optimum well placement and well spacing.

This study provides an integrated approach to the reservoir characterization of Wolfcamp Shale. Facies-based reservoir modeling is used to represent the geological and petrophysical heterogeneity as well as to understand the source and dynamic behavior of the reservoir fluids (hydrocarbon and water). Numerical simulation is then used for history-matching, forecasting and understanding major reservoir drivers. Given the non-uniqueness of reservoir modelling results, these outputs are cross-validated with complementary data and analysis (e.g., production data analysis, interference tests, microseismic, and geochemical data analysis). Reservoir modeling outputs are then used to calculate the EUR degradation as a function of well spacing, and then incorporated into a systematic economic evaluation of various field development scenarios.

As part of the work performed in this study, comprehensive analysis has been performed on both single- and multiwell pads to establish the advantages of each scenario. Single-well models have been instrumental in providing an understanding of fluid movement in sub-zone targets, the influence of relative rock properties of these intervals, and their impact on depletion profiles over time while multi-well models have provided key insights into understanding well-to-well interactions over time and the impact of these interactions on long-term forecasting. Validating such modeling results with other methodologies provides robust solutions and improved predictability both on a local and regional scale.

We provide an integrated modeling workflow for the Delaware Basin Wolfcamp shale that explores vertical and lateral well interactions over time. The workflow requires an interdisciplinary understanding of the reservoir, which is critical to develop well spacing solutions for these types of unconventional reservoir systems.

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