Unconventional/complex reservoirs

Tight Reservoirs-2015

Estimates of tight-reservoir hydrocarbon reserves continue to vary with uncertainty. What is known with certainty, though, is that current recovery rates are low and the upside is substantial.

When the October 2014 Tight Reservoirs feature went to press, the WTI crude oil price was at or near USD 100/bbl. When the feature was published, the price, although already declining, was still more than USD 80/bbl. And the October 2014 feature noted the fast-paced growth in exploration and development of unconventional hydrocarbon reservoirs and the associated need to determine how to accelerate and sustain longer-term production. Now, 1 year later and in a very different business climate with much lower hydrocarbon prices and greatly reduced well-drilling activity, there is a shift in focus. The need to understand, develop, and implement the means to increase reserves recovery (or to produce more from what we have while at the same time reducing costs) is now the priority.

In order to accomplish these more-prudent, more-sustainable objectives, increased attention is being placed on understanding fluid-flow behavior in tight and unconventional reservoirs, on perforating and stimulation optimization, on enhanced-oil-recovery methods applicable to such formations, and on modeling and forecasting economic production profiles and field economic limits in variable price environments.

Estimates of tight-reservoir hydrocarbon reserves continue to vary with uncertainty. What is known with certainty, though, is that current recovery rates are low and the upside is substantial. So, overcoming the challenges to reach more-aggressive, stretch targets in recovery and cost efficiency will be well worth the effort. The present business environment, though painful, presents an opportunity for the future. But, as always, collaboration across and among operators, technology and service providers, and academia will be necessary.

The papers featured this month provide a few examples of innovation, technology advancements, and learnings that can be applied to achieve more-sustained and more-economic production and reserve recovery.

Recommended Additional Reading

SPE 171580 A New Methodology To Forecast Solution Gas Production in Tight Oil Reservoirs by Shaoyong Yu, ConocoPhillips Canada

SPE 171826 Perforating With Deep-Penetrating Guns Followed by Propellant Treatment Yields Results in Tight Reservoirs—UAE Case Study by M.N. Aftab, ADCO, et al.

SPE 172663 Impact of Perforation-Tunnel Orientation and Length in Horizontal Wellbores on Fracture-Initiation Pressure in Maximum-Tensile-Stress-Criterion Model for Tight Gas Fields in the Sultanate of Oman by Andreas Briner, PDO, et al.

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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 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 SPE Monograph Acidizing Fundamentals. He is a member of the JPT Editorial Committee.