Technology Focus: Tight Reservoirs (October 2013)
Authors: Kubala Gregory 
Published: February 2015

Technology Focus

Tight reservoirs are still in the early stages of becoming a dominant source of energy and economic growth throughout the world for years to come. I recently read two distinctly different articles particularly relevant to tight reservoirs. One was written by an oil and gas consultant who applied the Pareto principle to the practice of multistage hydraulic fracturing of horizontal wells, which has pushed oil production to 20-year highs in North America. The other was authored by a major asset holder’s policy expert, who objectively addressed public perception of the oil and gas industry. Although our industry has developed a number of new technologies enabling better reservoir characterization, horizontal-well placement, and reservoir drainage, as well as gaining public trust, there does appear to be room for improvement.

We must continue to listen to the public and understand the concerns and issues. Our response should include transparency, research to address concerns, and development of workflows and technologies to address safety and protection of health and the environment. One such response by our industry is the growing priority of improving long-term wellbore integrity. Improvements are being made in mud removal, cement-system-design software and techniques, and environmentally friendly cementing systems with improved bonding and mechanical integrity.

From a production perspective, if 80% of production is coming from 20% of the stages, our industry needs to

Ensure that wellbores and fracture stages result in quality production

Recover the bypassed oil and gas

Evolve laboratories to understand the complex chemistry and physics of tight reservoirs

Experience demonstrates that generalized field development and production planning do not offer optimal resource recovery in tight reservoirs. Case studies show us that customized planning for landing the well, stimulating the reservoir, and producing the asset is the way to go. As this decade unwinds, we will see new workflows and technologies to ensure that wellbores are landed better, fracture stages are placed better, and bypassed oil and gas are recovered.

The laboratories of the future and new technologies created for refracturing/re-entry programs are of particular interest to me. Laboratory studies to determine fluid efficiency in a fracture need to reflect tight-reservoir conditions and not that of American Petroleum Institute RP 13M-4. Rock/fluid interactions are much more influential in tight reservoirs, and the industry needs to improve its methodology and standardization in such test measurements. Refracturing programs will be challenged to promote stimulation of new zones outside of those stimulated by the initial fracturing and restimulation of closed or damaged networks. New diversion technologies to simplify operations and reduce costs are to be anticipated for tight-reservoir production.

Recommended additional reading at OnePetro: www.onepetro.org.

SPE 159546 Stimulated-Shale-Volume Characterization: Multiwell Case Study From the Horn River Shale: II. Flow Perspective by Christine A. Ehlig-Economides, Texas A&M University, et al.