Abstract

The successes of horizontal-well completions in the Eagle Ford formation have increasingly attracted interest within the oil and gas industry. An improved stimulation technique using new fluids and proppants has resulted in better zonal coverage through improved diversion and tagging. Low-permeability reservoirs attract increased attention from oil companies because of increased demand and limited opportunities in conventional (higher-permeability) reservoirs.

This paper presents a case study of a horizontal well in the Eagle Ford reservoir. The reservoir rock is considered 100% dolomite with 9 to 12% porosity and permeability of 4.0E-5 md. Vertical wells in this area, even being hydraulically fractured, still produce below economic limits. Horizontal wells with multiple, transversal hydraulic fractures have shown to produce more than vertical wells and have been successfully applied in low-permeability reservoirs in Texas.

The principal objective of this paper is to show the analysis and selection process of a completion design for a new well to evaluate the reservoir parameters and determine the optimum hydraulic-fracture completion design, including fracture stages and an economics review. In this work, 3D fracture growth and conductivity models were calibrated and optimized using the existing fracture post-job reports of neighboring wells completed in the Eagle Ford reservoir.

This workflow could be applied to any low-permeability reservoir with the intent to optimize the number of hydraulic-fracture stages on a new horizontal well, minimizing the stages’ interference and maximizing the expected net present value (NPV). This workflow demonstrates an effective methodology for capturing essential characteristics of Eagle Ford reservoirs and offers a quantitative means and platform for optimizing shale reservoirs.

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