Production Performance in the In-Fill Development of Unconventional Resources

Abstract

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 175963, “Production Performance in the In-Fill Development of Unconventional Resources,” by Bilu V. Cherian, Sanjel; Matthew McCleary, Samuel Fluckiger, Nathan Nieswiadomy, Brent Bundy, and Sarah Edwards, SPE, SM Energy; and Rafif Rifia, Kristina Kublik, Santhosh Narasimhan, James Gray, Olubiyi Olaoye, and Hamza Shaikh, Sanjel, prepared for the 2015 SPE/CSUR Unconventional Resources Conference, Calgary, 20–22 October. The paper has not been peer reviewed. Data now show that the behavior of unconventional wells to in-fill drilling varies significantly across basins. A key influence may be changes in pore pressure and saturation (saturation history). This paper presents results from the analysis of the effect of in-fill drilling on parent-well performance, and describes a simplistic approach to understanding the effect of the quest for operational efficiencies and economic cycles on development strategies. Methodology This study focuses on two unconventional plays, the Eagle Ford and the Bakken. The objective was to model the well performance of the parent wells with the aim of matching and predicting in-fill-well performance. Because the two assets are at two significantly different portions of the development cycle (Eagle Ford is very early in its cycle), the Bakken data set has the luxury of modeling and matching the performance of the parent and in-fill, whereas the Eagle Ford portion of this study focuses on forward modeling and optimizing in-fillwell completions. The methodologies used in this study (parent-well modeling, petrophysical models, geomechanics, fracture modeling, production modeling, and in-fillwell/ depletion modeling) are discussed in detail in the complete paper. Bakken System Parent-Well Modeling Petrophysics. The Middle Bakken member was divided into three main facies. Petrophysical evaluation indicates that average porosity and average water saturation were 8 and 50%, respectively, for the Middle Bakken. Average Klinkenberg permeability for the entire Middle Bakken is approximately 0.02 md. Mercury-injection capillary pressure curves indicate that irreducible water saturation is between 30 and 40% for rock with porosity between 1 and 7%. Residual oil is between 30 and 40%. Accordingly, the moveable fluid is low (20–40%), and hydraulic fracturing was recommended to stimulate more production. The Three Forks formation was divided into five facies. Petrophysical evaluation suggests that the upper part of the Three Forks, Facies TF 23, has oil potential. Most facies are strongly affected by calcite and dolomite diagenesis, which allows alternating porosity development in some cases. In this area, the Middle and Lower Three Forks have higher water saturation, with very-low-permeability streaks (less than 0.007 md).