Standing alone as the shortest month of the year, February also features JPT’s Well Testing Technology Focus, reviewing the latest industry publications on the subject. Well testing has enjoyed a recent uptick in activity and interest as operators continually realize the value in understanding and monitoring the dynamic performance of their reservoirs. Whether it pertains to the deliverability of conventional oil and gas or the storage potential for carbon capture and storage, large-scale dynamic data remains one of the more coveted pieces to the subsurface puzzle.
There is no silver bullet for reservoir characterization. Instead, proper characterization will always be the result of integrating static and dynamic data, collected at varying scales, with a macro geological understanding.
Technology facilitates the collection of the aforementioned data. With the latest technologies pushing limits of what can be achieved, subsurface engineers must rigorously evaluate what reservoir characterization techniques and tools are suited for project objectives. Formation testing (FT) platforms provide many options for operators to get a first look at dynamic reservoir performance and nearly always precede a well test. After digesting the alphabet soup of acronyms, so many FT options exist that one may encounter what psychologists refer to as “choice overload.” FT objectives also may begin to overlap with objectives traditionally reserved for drillstem tests (DSTs), narrowing a long-standing technology gap. The current advances in FT tools are exciting, and using FT tools to perform a “mini-DST” makes for brilliant marketing. However, “mini” could mean up to 10,000 times less produced volume, which undoubtedly affects objectives thought to overlap.
Subsurface complexity is mitigated by defining clear objectives and executing data-collection programs to reduce uncertainty. Caution should be taken in selecting how to dynamically test your reservoirs. Regardless of how advanced hardware becomes, achievable objectives always will be dependent on key factors such as rock and fluid properties, reservoir geometry, and local regulatory and environmental considerations.
This month’s papers highlight ongoing developments from different segments of the well‑testing discipline.
Dive into valuable lessons learned from a frontier carbon capture, use, and storage project, backed by an impressively sized data set and an in‑depth review of multiphase effects. This case study covers differing saturations around the wellbore region and fluid types in operations and should have global applications.
Learn about the limitations and potential pitfalls of nonisothermal effects in pressure transient analysis, which pose challenges in the reservoir characterization of geothermal wells. Sensitivities to thermal effects on reservoir rock properties provide intriguing insights. Completion efficiency also may be affected by thermal effects, resulting in additional pressure drop at sandface.
Finally, catch up on one of the weapons most recently added to the well-testing arsenal with powerful new FT tools that feature industry improvements for greater flexibility and improved data reliability.
This Month’s Technical Papers
CO2 Injectivity Test Proves Concept of CCUS Field Development
Dynamic Simulation Platform Aids Deep Transient Tests, Well-Control Safety
Reservoir Modeling Predicts Effect of Cold-Water Injection on Geothermal PTA
Recommended Additional Reading
OTC 32610 Multiphase Flowmeter Comparison in a Complex Field by Mohammed Alqahtani, Saudi Aramco, et al.
IPTC 23050 Frequently Asked Questions in the Interval Pressure Transient Test and What Is Next With Deep Transient Testby Saifon Daungkaew, SLB, et al.
Jeffrey Gagnon, SPE, is a subject-matter expert of transient well testing at ExxonMobil. He and his team oversee ExxonMobil’s worldwide exploration and appraisal testing (including design and planning, onsite operations supervision, and data interpretation and integration) while supporting pressure transient analysis for producing assets. Gagnon has co-authored SPE manuscripts regarding reservoir characterization and simulation. He holds MS and ME degrees in petroleum engineering from Robert Gordon University and Texas A&M University, respectively, and an undergraduate degree in civil engineering from the University of New Hampshire. Gagnon is a member of the JPT Editorial Review Board and can be reached at jeffrey.gagnon@exxonmobil.com.