Design Optimization of Horizontal Wells with Multiple Hydraulic Fractures in the Bakken Shale

Abstract

Hydraulic fracturing is currently the completion method of choice in most tight reservoirs; however, the ultimate performance of fractured wells is severely affected by the interfering effects inside the fracture and interfractures. Previous simulation studies investigated the effects of well spacing and fracture length on well productivity in low-permeability oil and gas reservoirs. It was shown that the most important parameters for determining the optimum fracture length are the formation permeability and the stimulated reservoir volume (SRV). Although a number of studies have examined the performance of horizontal fractured wells and the fracture geometry effect, fracture spacing and intersecting angles in vertical and horizontal wells should be further investigated. This study presents the results of a tight oil reservoir analogy. Reservoir parameters considered include local rock stresses, rock compressibility, absolute and relative permeability, and porosity. The well-completion parameters included fracture length, height, width, conductivity, number and spacing between fractures, fracture intersecting angle, and cased- vs. openhole completion. Fracture modeling considered rigorous description of the hydraulic fracture properties and finite difference reservoir modeling. Economically attractive reserves recovery was modeled through multiple fracture placements in a 10,000-ft horizontal well. Numerical simulation showed that oil recovery increased between 8 to 15%, while net present value (NPV) increased 8 to 24%, as the number of fractures increased. Based on the critical assumptions in the study (permeability, natural fracture distribution, and stress orientation), an optimum number of fractures was identified. Openhole completions provided better performance in most cases, and recovery was greater for a higher number of contributing perpendicular vs. longitudinal fractures. The results of the study hopefully can be used to improve the understanding of the role of fracture geometry, spacing, and open/cased-hole completion strategy to enhance an operator's optimum completion design.

Stochastic optimization of hydraulic fracture and horizontal well parameters in shale gas reservoirs

“…Luigi Saputelli et al, (2014) performed optimization of horizontal wells with multiple hydraulic fractures in the Bakken Shale. Economically attractive reserves recovery was modeled through multiple fracture placements in a 10,000-ft horizontal well.…”

Application of Pressure-Monitoring Data in Land-Based Unconventionals

“…This information is then used to optimize stimulation operations and gain better understanding of reservoir performance during the production phase. The knowledge gained can then be used to improve the design and fracturing of subsequent wells (Saputelli et al 2014). All this information contributes to the foundation of knowledge used to assess the effectiveness of the field development plan, determine the economic viability of the project, and optimize the stimulation and depletion phases of the wells.…”

Optimum Well Completion Strategies in Tight Oil Reservoirs

“…Openhole completions provided better performance in most cases, and recovery was greater for a higher number of contributing perpendicular vs. longitudinal fractures (Saputelli et al 2014). Based on the critical assumptions in the study (permeability, natural fracture distribution, and stress orientation), an optimum number of fractures was identified.…”