Abstract
The success of horizontal well completions in the Bakken formation has increasingly attracted much interest within the oil and gas industry. Improved stimulation techniques including the use of new fluids and proppants, better zonal coverage through improved diversion and staging, and/or re-fracture treatments contributed to this success. This paper presents the results of a fracture modeling and multi-well simulation study to evaluate down-spacing potential for horizontal wells. This study also examines how the number of stages along the lateral, proppant type, treatment volume, fracture conductivity, and effective oil permeability affect production profiles and oil recovery in the middle Bakken formation, North Dakota.
In this work, a lumped 3D fracture growth model was calibrated with direct fracture mapping observations that showed significant upward height growth into the Lodgepole formation. The horizontal well orientation is selected to promote transverse fractures. This paper provides details about the fracture treatment designs and subsequent integration of the fracture geometry and conductivity descriptions into the reservoir model. Various fracture treatment designs are evaluated, with the goal of optimizing fracture conductivity and minimizing upward height growth (which can be a problem in the middle Bakken).
The results of this study showed a significant infill drilling potential because of the low estimated effective oil permeability (0.002-0.04 mD). Reducing the horizontal well spacing from one to two or three wells per 640 acres should significantly increase oil recovery. The optimum number of fracture treatment stages along the horizontal lateral depends largely on reservoir permeability, lateral length, and number of wells per section.
