An integrated completion and production workflow was used to optimize the fracture stimulation treatments in a group of vertical Wolfbone wells located in the Delaware Basin of West Texas. This workflow integrated advanced petrophysical processed logs and anisotropic stress models, derived from full waveform dipole sonic measurements, with detailed fracture simulation to determine perforating and staging strategies which would provide the best fracture coverage and optimize the number of stages. The flow-channel fracturing (FCF) technique, which provides a novel approach for achieving fracture conductivity, was also implemented on several of the study wells to significantly improve the effectiveness of the fracture stimulation treatments. Through fracture diagnostics, detailed post fracture modeling, and production analysis techniques which utilized production logs, an understanding of the effectiveness of the stimulation treatments (fracture length/conductivity) as well as calibration of the petrophysical and geomechanical models was achieved.
This paper will demonstrate how the implementation of an integrated well optimization workflow on several vertical Wolfbone wells has improved overall well production performances, reduced drilling and stimulation costs, and has ultimately paved the way forward for horizontal development of the Wolfbone acreage.
The Wolfbone is the local name given to vertical wells in the Delaware Basin with commingled production from the Wolfcamp and the Bone Spring intervals (see Fig. 1). These wells are commonly drilled to 9,500 – 12,500ft TVD with the targeted interval encompassing gross thicknesses of up to 2,500ft. As the Wolfbone is comprised of multi-stacked conventional and unconventional packages, the interval is characterized by highly heterogeneous lithologies and formation properties. It is typical to find interbedded limestones, shales, and sandstones with porosity and permeability in the ranges of 4–15% and 0.001–1.0 mD, respectively. Although the shallow intervals - like the Avalon and the 1st and 2nd Bone Springs- are viable targets, the majority of operators elect to initially complete the overpressured zones from the base of the Wolfcamp to the top of the 3rd Bone Spring interval. Based on pressure-management and economical considerations, the shallow horizons may be completed on subsequent stimulation mobilizations.