Improving Field Performance and Asset Productivity by Optimizing Well Placement in the Presence of Natural Fractures

Abstract

Unconventional reservoirs have characteristics that differ from traditional conventional reservoirs. The productivity profile of an unconventional well can be significantly different from a conventional well, in that the production rate declines faster in an unconventional well. Therefore, properly planned well operations are crucial to optimize costs and production from these shale assets. This includes understanding the reservoir physics, planning optimal well spacing, improving well performance from completions, and simulating refracturing effects on well production. This paper presents a new multidisciplinary method to help improve field performance and productivity in unconventional reservoirs. A multidisciplinary approach is necessary for economical and successful operations in unconventional reservoirs. In unconventional fields, wells are drilled quickly; therefore, rapid decision-making is necessary. Currently, fracture modeling is performed using either fine local grid refinements or dual-porosity dual-permeability models, which can be cumbersome and time-consuming. This paper presents a new approach that uses multiple shale-specific features and unstructured models, which allows users to specify discrete natural fracture networks (NFNs) and hydraulic fractures with arbitrary orientations connected to practical well trajectories. The automated gridding technique significantly simplifies the workflow, thus allowing users to focus on addressing issues in the engineering space by streamlining the setting up of complex reservoir simulation models. The approach is applicable to black oil and compositional models of all fluid types. Using parallel capability, performance can be enhanced severalfold. The new approach helps enable modeling of multiple scenarios by modifying parameters easily; thereby, results are readily available to help operators plan optimal well and fracture spacing and length. This paper highlights how well productivity can be improved by optimizing well placement and incorporating the effect of NFNs and hydraulic fractures.