Unconventional/complex reservoirs

Unconventional and Tight Reservoirs-2024

Unconventional reservoirs bear a unique perplexity in that, at every scale, they are different from their conventional counterparts and even one another. This month’s selection of papers is all about those differences.


Unconventional reservoirs bear a unique perplexity in that, at every scale, they are different from their conventional counterparts and even one another. Small nuances in any one parameter can result in a vastly different well result, which may affect how an area, or even an entire play, is interpreted. This month’s selection of papers is all about those differences, in recognition that it is technology that drives innovation through understanding what these differences mean and how best to extract value from these vast resources.

Starting at the well scale and looking at the benefits of knowing the efficacy of each stimulation stage, paper URTeC 3864145 is from the Ordos Basin in China. Investigating hydraulic fracture performance on a stage-by-stage basis proves time and time again that understanding the details can improve overall development outcomes. The case study reviews two hydraulic fracture diagnostic techniques used in combination to determine water breakthrough and shutoff plans.

Zooming out to the play scale, paper SPE 216292 is focused on the most variable of unconventional reservoirs: the carbonate reservoir. This case study of the Austin Chalk formation in Texas analyses the production uplift from application of horizontal, multistage fracture stimulation technology in tight or fractured carbonate reservoirs. The application of unconventional technology in carbonate reservoirs can extended field life, and the deployment of this technology should be considered for any redevelopment or reassessment of potential resources trapped in tight carbonate reservoirs.

Finally, paper OTC 34832 draws on the concept of innovation that is required to unlock unconventional resources. Novel methods of stimulation are the cornerstone of unconventional technology in that well stimulation is a basic requirement of all low-permeability reservoirs. The paper describes a trial pilot from idea through execution from Kuwait Oil Company for enhanced oil recovery in tight formations using downhole hydrogen generation from in-situ exothermic multistage chemical reactions between two unique hydroreacting agents. The paper also provides lessons learned and optimization insights from the trial, concluding that a successful, low-cost alternative stimulation technique was demonstrated and repeatable.

This Month’s Technical Papers

Integrated Technique Provides Effective Water Diagnostics in Tight Sand

Extended Laterals and Hydraulic Fracturing Redevelop Tight Fractured Carbonates

Downhole Hydrogen-Generation System Stimulates Challenging Formations in Kuwait

Recommended Additional Reading

SPE 216139 Tight Gas Reservoir Characterization and Comparison of PLT Methods: Microseismic Monitoring, Fiber-Optical Production Logging, and Tracer-Coated Sand Monitoring Applied in the Same Well by Xiao Yao, Petrochina, et al.

SPE 216149 New Insight in Developing Tight Fractured Carbonate Reservoirs, Mishrif Formation, West Kuwaitby M. El-Jeaan, Kuwait Oil Company, et al.

SPE 215712 Successful Utilization of In-Situ Dune Sands in Saudi Arabian Unconventional Frac Operationsby Nahar Qahtani, Saudi Aramco, et al.

Larissa Walker, SPE, graduated with honors from the University of Waterloo in 2005 with a Bachelor of Applied Science degree in geological engineering and began a career with Shell as a petrophysicist in Calgary. Her more than 18 years of energy industry experience cover a wide spectrum of unconventional resources including deep, sour gas carbonates; tight sand and shale plays of Western Canada; the Appalachian Basin Shales in America; and coal seam gas in Eastern Australia. These complex assets provide the foundation of Walker’s deep technical and project management insight into the key elements that deliver value throughout each stage of a project’s life cycle. In her current role as technical lead, she is responsible for the front-end development for Shell in Queensland’s Bowen Basin Permian tight gas sand (TGS) assets. The successful case delivery of the Bowen TGS Capital Project has the potential to sustain the existing Queensland Curtis Liquefied Natural Gas project while providing gas and liquids into the East Coast domestic market. Walker is a member of the JPT Editorial Review Board and can be reached at larissa.walker@shell.com.