Technology Focus: Tight Reservoirs (October 2009)
Authors: Kubala Gregory 
Published: February 2015

Technology Focus

The basic points of last year's feature statement continue to dominate the industry's attention in tight reservoirs. First, tight reservoirs present unique challenges related to hydrocarbon storage and flow in complex reservoirs, thus requiring an improved fundamental understanding for effective production. Second, new technologies and processes will increase reservoir contact and improve drainage patterns, which, in turn, will improve operations efficiency, environmental stewardship, production, and recovery significantly. Third, continuous subsurface monitoring and measurement during drilling, completion, stimulation, and production will be critical to characterize the complex rock/reservoir heterogeneity, to evaluate the drainage behavior, and to validate the optimization of the field-development strategy.

Multiple transverse fracturing in horizontal wells is probably the most widely accepted production technique in the last decade. This technique is moving to a greater number of fracturing-treatment stages per lateral and is even moving offshore. Despite the acceptance of this technique, the industry has bypassed the majority of the assets in the reservoir. In time, refracturing and/or re-entry campaigns will be attractive initiatives to drain the unrecovered hydrocarbons. Efficient refracturing campaigns will require a solid understanding of fracture reorientation with the application of diversion technology and microseismic monitoring. Understanding fracturing-fluid interactions with the rock and reservoir fluids, with an emphasis on the effect on production, is evolving. Liquid/gas wettability, contact angles, and water blockage all are important to production as the fracturing fluid aims to contact an ever-increasing amount of the reservoir surface.

New models and analysis for gas-flow behavior and gas production are in their infancy. In the future, microseismic analyses of fracture networks will be coupled with geomechanics to predict fracture networks. Understanding rock heterogeneity of the near-wellbore region and overall reservoir will lead to improved perforation-interval selection, fracture initiation, and fracture control. Additional modeling will lead to optimizing both single-well treatments and spacing and pattern-development optimization. The progress being made in these areas is improving the industry's success rate in reservoir drainage.

Papers selected for this month's feature and for the additional reading list focus on the industry's progress in these areas.

Tight Reservoirs additional reading available at OnePetro: www.onepetro.org

OTC 20269 • "Unlocking the Unconventional Oil and Gas Reservoirs: The Effect of Laminated Heterogeneity in Wellbore Stability and Completion of Tight Gas-Shale Reservoirs" by Roberto Suárez-Rivera, Schlumberger, et al.

SPE 120271 • "Predicting Production Outcome From Multistage, Horizontal Barnett Completions" by Bill Grieser, Halliburton, et al.

SPE 121812 • In-Situ Water-Blocking Measurements and Interpretation Related to Fracturing Operations in Tight Gas Reservoirs" by B. Bazin, IFP, et al.