Cloud Computing Optimizes Vaca Muerta Well Spacing, Stimulation Design

Abstract

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 204142, “Well Spacing and Stimulation Design Optimization in the Vaca Muerta Shale: Hydraulic Fracture Simulations on the Cloud,” by Sahil Malhotra, SPE, Alejandro Lerza, SPE, and Sergio Cuervo, Chevron/YPF Joint Venture. The paper has not been peer reviewed. _ Well spacing and stimulation design are high-impact design variables that can dictate the economics of an unconventional development. The objective of the complete paper is to showcase a numerical simulation work flow with emphasis on a hydraulic fracture simulation methodology that optimizes well spacing and completion design simultaneously. The work flow is deployed using cloud computing functionality. Objective The Vaca Muerta shale has grown in drilling activity and overall production significantly over the past decade. The mode of development started from vertical wells with multistage hydraulic fractures, with a transition to horizontal wells in the early 2010s. Over the past few years, the designs have transitioned to fracturing designs with lower-viscosity fluids with tighter cluster spacing. These designs have demonstrated improved production in wells drilled in multiple zones. While an emphasis has been made on optimizing stimulation designs, well spacing has not been studied thoroughly yet. The objective of the current work is to optimize well spacing and stimulation designs to maximize estimated ultimate recovery (EUR) and lower the unit development cost per barrel. Stimulation designs contain design variables including cluster spacing, clusters per stage, proppant and fluid amount, fluid type, proppant type, and perforation design. Unit development cost is defined as the capital expenditure per barrel of EUR. Modeling Work Flow The work flow was used on a three-well pad in a field in the Neuquén basin targeting the Vaca Muerta. Two wells were drilled and completed in the upper zone, and one well was completed in the lower zone. The pad was initially designed for four wells, but one lower-zone well was abandoned because of drilling-related issues. Well A and Well C were pumped with high-density completions (HDC) designs, and Well B was pumped with a conventional design. The HDC design involved pumping larger proppant and fluid amounts at tighter cluster spacing than in the conventional design.