The Next Opportunity To Improve Hydraulic-Fracture Stimulation

Abstract

Distinguished Author Series articles are general, descriptive representations that summarize the state of the art in an area of technology by describing recent developments for readers who are not specialists in the topics discussed. Written by individuals recognized as experts in the area, these articles provide key references to more definitive work and present specific details only to illustrate the technology. Purpose: to inform the general readership of recent advances in various areas of petroleum engineering. Abstract Forty years ago, most people in our industry would have claimed that producing economic flow rates from nanodarcy formations was simply impossible. Thirty years ago, tax incentives were introduced by the US Congress to encourage drilling of ’unconventional’ tight gas reservoirs in which the permeability was near 0.1 md. Today, our industry is voluntarily drilling into formations that are 1/1,000 as permeable, and making tremendously profitable wells! The technology that facilitated this ’impossible’ feat is hydraulic fracturing-specifically, the opportunity to initiate multiple transverse fractures from horizontal wells. While hydraulic stimulation has provided tremendous advances in our ability to develop lower-permeability resources, the corresponding challenges have not been addressed fully. This article summarizes one perspective on future opportunities that will allow even more-thorough and more-cost-effective recovery of hydrocarbons from tight reservoirs. Reservoir Contact In highly permeable formations, conventional wells may be completed without stimulation. The borehole and perforations provide sufficient reservoir contact to achieve profitable hydrocarbon production. However, more than 90% of the wells currently drilled in North America require fracture stimulation to recover reserves from low-permeability formations at economical rates. Hydraulic fracturing involves pumping a fluid at sufficiently high rates and pressures to extend cracks into the formation surrounding the wellbore. Granular materials are injected to prop the created fissures open to delay their collapse. These created fractures can increase the contact between the wellbore and reservoir dramatically and are the key that has unlocked tremendous hydrocarbon resources contained in tight formations.