With crude-oil prices continuing to languish, margins in tight-reservoir-asset developments have continued to tighten and new drilling and completion activity, of course, is substantially reduced. Looking back 2 years, the focus in onshore-asset development has essentially shifted entirely from fast-paced growth of tight hydrocarbon reservoirs to production enhancement from existing (but still profitable) wells, as well as to maximizing productivity from the smaller number of new well completions.
However, enhancing production from multizone, propped-fracture completions in tight reservoirs, for example, is not straightforward. There are questions to address, especially with respect to the understanding of the contribution of natural fractures and induced unpropped (IU) fractures. How can natural and IU fractures be accessed or enhanced in new wells or in existing wells that are candidates for refracturing? Is there an opportunity with the use of smaller proppants? What are the implications of fracture and well spacing? Can the pumping and rate steps of fracture stages be redesigned for improved containment and fracture conductivity, even formation permeability enhancement? Are there learnings from long-term injection operations in tight reservoirs that can be applied to well-stimulation operations?
Also, for existing well completions, can reactive fluid (e.g., acid or other chemicals) be used effectively, and, if so, how? Can well production be enhanced by injection of fresh water to remove salt potentially residing in existing natural-fracture systems?
The papers featured this month provide assessments and discussions concerning these and other related questions. Each paper is unique, but they all share the intent of advancing efforts in enhancing production from existing and new well completions in tight reservoirs.
SPE 180274 Study of the Rock/Fluid Interactions of Sodium and Calcium Brines With Ultratight Rock Surfaces and Their Effect on Improving Oil Recovery by Spontaneous Imbibition by M.K. Valluri, Texas A&M University, et al.
SPE 169843 Estimating Long-Term Well Performance in the Montney Shale Gas Reservoir by Vu P. Dinh, Murphy Oil, et al.
IPTC 17739 A Comparison of North American and International Risks in Unconventional Resource Plays by D. Nathan Meehan, Baker Hughes
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.
New-Frontier Reservoirs II
Leonard Kalfayan, SPE, Global Production Engineering Adviser, Hess Corporation
20 September 2016