New-Frontier Reservoirs II

With the recent increase in new-well activity in unconventional reservoirs and the well-factory approach, a natural limitation exists in the capacity for implementing hydraulic-fracturing optimization. An even greater limitation exists with the consideration of stimulating production from existing wells in decline. Great strides have been made in drilling and completion efficiencies and well-cost reduction during the past several years. That focus has been most important in the lower-for-longer oil-price environment we have fought through.

Naturally, that focus has, to some extent, limited alteration of initial-stimulation design—for example, with respect to fracture-stage sizes, fracture-spacing optimization, and proppant types and volumes. Furthermore, restimulation of existing wells is not an area that has received as much attention as other areas, and, where it has, the focus has been on simply repeating refracturing with proppant. Remedial chemical-treatment options have not been explored to a significant extent, especially at the field level. Instead, greater attention has been placed on how to make the leap from primary production achieved from initial well completion to field-scale enhanced oil recovery (EOR). The in-between measure of remedial production enhancement in existing wells is largely being skipped.  

With low primary-recovery rates in unconventional reservoirs and the longer-term development prospects for EOR applications on a fieldwide scale, the potential for accelerated completion optimization in new wells and production-enhancement treatments in existing wells is substantial and perhaps comes with more immediate returns.  

Along those lines, the first of three papers featured this month addresses the optimization of fracture spacing and penetration ratio in unconventional reservoirs. The other two papers discuss studies related to remedial production and recovery improvement in existing wells—surfactant soak and flowback treatments in oil-bearing formations and solvent treatments for water and condensate blockage in tight formations, respectively.

This Month's Technical Papers

Section-Based Approach Optimizes Unconventional-Reservoir-Fracture Spacing

Soaking Flowback With Surfactant Improves Oil Recovery in Unconventional Reservoirs

Coupled Capillary-Pressure and Three-Phase Flash Models Simulate Liquid Blockage

Recommended Additional Reading

SPE 189805 Dual-Permeability Matrix-Fracture Corefloods for Studying Gasflooding in Tight Oil Reservoirs by Peng Luo, Saskatchewan Research Council, et al.

SPE 190214 Underlying Mechanisms of Tight Reservoir Wettability and Its Alteration by Peng Luo, Saskatchewan Research Council, et al.

SPE 187542 Limitation of EOR Applications in Tight Oil Formation by Ahmed Mansour, Texas Tech University, et al.

Leonard Kalfayan, SPE, is a global production engineering adviser with the Hess Corporation in Houston. He has 35 years of experience in the industry, working with a major operator and a major pressure-pumping company and as an independent consultant before joining Hess in 2009. Kalfayan’s background is in conventional and unconventional oil and gas, geothermal production enhancement and stimulation, new-technology development and deployment, and business development. He was an SPE Distinguished Lecturer in 2005 and has served on numerous SPE program and technical committees. Kalfayan is author or coauthor of more than 30 SPE and other society publications, serves as a technical reviewer for SPE Production & Operations, and is coeditor of the SPE monograph Acidizing Fundamentals. He is a member of the JPT Editorial Committee and can be reached at

New-Frontier Reservoirs II

Leonard Kalfayan, SPE, Global Production Engineering Adviser, Hess Corporation

01 October 2018

Volume: 70 | Issue: 10