Tight Reservoirs

Exploration and development of unconventional hydrocarbon reservoirs continue to grow at a pace that exceeds our understanding of the nature of these ultratight formations and how to sustain longer-term production from them. This is confounded further by the expansion of the industry into the broader and increasingly mysterious realms of liquid-rich and tight oil reservoirs beyond the relatively better-understood tight gas formations with their longer history of exploitation. With this greater breadth of activity, the unknowns, uncertainties, and challenges are increasing.

Already, estimates of unconventional hydrocarbon reserves have varied greatly, and the financial and future-energy-outlook implications of such wide-ranging uncertainty are enormous. With the industry moving forward with exploration and development in the broader categories of unconventional resources globally, it is of paramount importance to assess and improve the different methods and tools for estimating reserves, to establish their accuracy and credibility. And this must be accomplished in conjunction with increasing our fundamental understanding of unconventional formations at the nanoscale. This is a considerable challenge but one with significantly greater emphasis and efforts across the academic and industry research-and-development landscape.

In conjunction, there is increasing attention on addressing the immediate issue of rapid well-production declines from the often prolific, but short-lived, initial production rates. With that in mind, methods including the use of enhanced recovery fluids and well-pattern schemes, and reactive fluids such as acids in drilling, completion, and stimulation processes, are beginning to receive genuine consideration. The importance cannot be overstated because alternatives to hydraulic fracturing may become a necessity, at least in certain areas of the world. Through special core analysis and flow studies, visualization techniques, and simulation, acid stimulation in carbonate-rich tight oil formations (as one example) may find greater and more-creative application beyond the acid spearheads ahead of hydraulic-fracturing stages. Other strategies for enhancing production and extending production performance, such as through imbibition and post-stimulation shut-in strategies, especially in liquid-rich and tight oil developments, are receiving more attention and are providing new and important learnings, too.

The papers featured this month provide new insights and examples in some of these key, and exciting, areas of current focus in unconventional, tight oil and gas, and shale developments. The reader is encouraged to delve into these topics and continue to monitor progress, which is moving at a fast pace.

This Month's Technical Papers

Probabilistic Evaluation of Global Technically Recoverable Tight Gas Resources

Evaluation of Strategies for Enhancing Production of Low-Viscosity Liquids

Effect of Low-Concentration Hydrochloric Acid on Properties of Shale Rocks

Recommended Additional Reading

SPE 163814 Prediction of SRV and Optimization of Fracturing in Tight Gas and Shale Using a Fully Elastoplastic Coupled Geomechanical Model by M. Nassir, University of Calgary, et al.

SPE 167092 Evaluating Treatment Methods for Enhancing Microfracture Conductivity in Tight Formations by Philip D. Nguyen, Halliburton, et al.

SPE 167713 Water Loss vs. Soaking Time: Spontaneous Imbibition in Tight Rocks by Q. Lan, University of Alberta, et al.

Leonard Kalfayan, SPE, is a global production engineering advisor with the Hess Corporation in Houston. He has 34 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 a 2005 SPE Distinguished Lecturer and has served on numerous SPE program and technical committees. Kalfayan is author or coauthor of more than 30 SPE and other journal publications, serves as a technical reviewer for SPE Production & Operations, and is coeditor of the upcoming SPE Monograph Acidizing Fundamentals. He is also author of the book Production Enhancement With Acid Stimulation and coauthor of the book The Energy Imperative. Kalfayan is a member of the JPT Editorial Committee.

Tight Reservoirs

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

01 October 2014

Volume: 66 | Issue: 10