Technology Summary 

It appears that the oil industry has been experiencing another one of those periodic oil-price challenges for the last several months. The oil prices have declined from the highs of last summer by about one-half. Even though it appears that this time it may take a while, it is a market that will certainty recover. As I have said on these pages before, the best cure for low oil prices is low oil prices. While we have to watch our cash flows to survive through another price dip, we also know that we cannot forget about the future and we must position ourselves now in order to seize it when the economic climate improves. This means continuing to invest in people, technology, and knowledge within reason. We have three papers to stimulate the grey cells this month.

One reason for the depressed oil prices is the tremendous success of shale-oil production technology in North America. New technology in horizontal drilling and stimulation has caused production from ultratight oil formations to increase rapidly over the last decade. These days, it is not uncommon to see a horizontal well with 20 to 40 hydraulic fractures, but the technology exists to place up to 100. Systematic Study of Bakken Well Performance Over Three Well-Completion-Design Eras reviews the development of well-completion technology in shale-oil reservoirs through hydraulically fractured vertical wells, horizontal wells, and very successful multistage fractured horizontal wells.

Even though we produce a significant amount of shale oil, there is still more left behind in the reservoir than what is produced. While initial rates are high, recovery factors for these types of reservoirs are predicted to be low, at approximately 5 to 10%. Unlike conventional reservoirs, waterflooding does not appear to be a viable secondary option because of its low injectivity. Recent analysis has shown that gas injection may be an effective alternative. C ompositional Modelling of the Diffusion Effect on EOR Process in Fractured-Shale-Oil Reservoirs by Gasflooding investigates the effects of diffusion on recovery performance.
One of the problems with waterflooding is bypassing the target zone because of viscous fingering caused by high oil viscosity and/or channelling caused by formation heterogeneity. One commonly used technology is reducing the mobility of the injected water by thickening it with a polymer. Status of Polymer-Flooding Technology is a timely paper reviewing this technology, which should work in principle but sometimes fails in practice because it requires care in its application. The paper reviews a number of polymer-flooding projects and associated problems.

Gökhan Coskuner, 
Issue Coordinator

About the Issue Coordinator
Gökhan Coskuner has more than 25 years of industry experience and currently works as Manager of Enhanced Oil Recovery and New Technology in the Heavy Oil and Gas Department with Husky Oil Operations Limited. Previously, he worked as Asset Manager and Reservoir Engineering and Development Lead in Oil Sands, as a team leader involved in the development and optimization of two deep basin gas fields, and as a reservoir engineer in projects ranging from gas storage to offshore field delineation and development. Before joining Husky Oil, Coskuner worked for Agip as a reservoir-engineering advisor, Scientific Software Intercomp as a senior consulting associate, and at Imperial Oil, Shell Canada, and the Petroleum Recovery Institute in various research capacities. He holds a BSc degree from the Middle East Technical University in Turkey and MSc and PhD degrees from the University of Alberta, all in petroleum engineering. Coskuner is past Executive Editor of the Journal of Canadian Petroleum Technology. He has been a member of the Journal of Canadian Petroleum Technology Editorial Review Board since 1990, was a director of the Petroleum Society, and the general chairman for the 2004 Canadian International Petroleum Conference. Coskuner was the recipient of the Petroleum Society’s Outstanding Service Award in 2009 and SPE’s Distinguished Member Award in 2013, Outstanding Service Award, and A Peer Apart Award in 2014. 

Paper Summaries

Systematic Study of Bakken Well Performance Over Three Well-Completion-Design Eras discusses the Bakken well-production behaviour under different well-completion designs in three different eras. Flow regimes are identified in production data from each era. Once boundary-dominated flow is identified, the production rate and duration at the start of boundary-dominated behaviour are observed. Then, the expected ultimate recovery and gas/oil ratio are compared with the three completion eras. Finally, simple relationships between production behaviour and completion design are summarized.

Compositional Modelling of the Diffusion Effect on EOR Process in Fractured-Shale-Oil Reservoirs by Gasflooding discusses the role of diffusion effect in field-scale displacement and in the presence of viscous flow. A dual-permeability model coupled with diffusion that characterized the dispersive-convective flux through nanopores in shale-oil reservoirs during the gas-injection process is presented. The results produced by this model are in good agreement with experimentally measured data in shale rocks. The significance of inclusion of matrix/fracture-diffusion rate in the oil phase and diffusion within the matrices in tight shale-oil reservoirs is highlighted. The diffusion effect on gasflooding efficiency is summarized, which is implemented in two hydraulically zipper-fractured horizontal wells in liquid-rich shales.

Status of Polymer-Flooding Technology provides an update on the status of polymer-flooding technology, focusing more on field applications than theoretical and laboratory research. It covers practical aspects of polymer flooding. Especially, it summaries the field performance worldwide. The screening criteria are also discussed and updated on polymer flooding. The data and analysis presented in this paper will give readers updated information about polymer flooding, as well as a guide to the relevant research. Survey data will also provide operators with reference data for project design and optimization.