Steering the unconventional developments has been a roller coaster ride, not only in the areas of financing and profitability, but also in the technical execution of the well construction and completion phases. This is particularly the case for aspects related to completion and hydraulic fracturing operations.
There are few parties, I believe, who would disagree that the drilling community has quickly provided an extremely consistent and efficient learning curve, something that the completion/fracturing discipline has unfortunately been much slower to achieve.
It’s not at all surprising. Efficiently extending conventional technologies and focusing on key requirements (i.e., getting from point A to point B) worked well for the drill crews. Commendably and efficiently, they were able to deploy easily and gradually learn in an almost linear fashion. This has resulted in remarkable delivery records in all unconventional games.
However, completions, namely hydraulic fracturing, has been a very different journey and involves solving a very different problem, with many more variables, inherent complexities and multiple degrees of freedom.
Since each unconventional zone is potentially distinct (just like drilling), however, these differences can extend to striking trends and surface features within the zones, as well as subtle variations along individual lateral wellbores. . For example, unlike drilling, the shape (and even sequence) of an offset wellbore completion can easily affect completion operations in the current wellbore.
It is highly likely that much of the initial misdirection of energy and effort resulted from an overenthusiastic application of conventional planar fracturing technology and knowledge to the unconventional environment. Perhaps the initial lack of effective diagnostic tools and approaches played a role, a problem that seems to have been understandably resolved in recent years. However, there was also a likely inherent engineering bias among engineers in the industry’s fracking staff.
The bulk of engineers in the industry had entered the unconventional after at least 2 decades of well-understood, well-defined, and highly effective physics-based analyzes of conventional planar fracturing operations.
Indeed, in some areas, this error persists. For example, the selection of proppants is apparently done based on long-established criteria put in place in the 1970s and 1980s, and quite appropriate for planar fracturing. While the reality is that the proppant plays multiple very different roles in unconventionals, bridging, plugging, wedging, deflecting, etc.
This has led to a “tearing the rule book” situation within the industry (which is ongoing) as lower grade sands and micro-/nano-proppants find applicability, as well as quality ceramics for a strategic place in the divide. Yet you can ask any fracturing engineer to select a proppant for unconventionals and they will almost immediately request performance data at 2 lbs/ft2as if we were going through proppant packs on all the geometry created.
This greatly increased level of complexity led to a general failure of the linear model in terms of its effectiveness in advancing optimal completion solutions. As a result, the early years of unconventional completion learning were largely “lost” in this linear fashion.
Lost to prevalent “suck-it-and-see” methodologies and applying planar fracturing understanding, all combined with a “watch your neighbor” approach and embracing change incrementally. Nonetheless, ever-adaptable, the fracking community continually recognized this failure and adjusted strategy when and where they could.
While some linear solution approaches continued, the first steps of big data approaches then began to appear – intuitive (almost naive even), simplistic, academic and not very effective at all, but they offer a first glimpse of the light at the end of the tunnel. Plus, the ever-inventive drive for industry-significant completion diagnostics, such as Distributed Temperature Sensing (DTS), Distributed Acoustic Sensing (DAS), as well as downhole video and now monitoring sealed wellbore pressure. We also have new test site data coming, such as Hydraulic Fracturing Test Site 2 (HFTS2) in the Delaware Basin portion of the Permian Basin. All these developments probably mean that we are entering a new era.
This shift in bias/influence from physics-based application/learning (using existing knowledge of conventional fracturing) to emerging data-based understanding plays a fundamental role in this journey. It is also the subject of more reports and discussions.
Data is finally used to make decisions and provide support to confirm/adjust physics-based thinking; rather than selectively filtering out data that matches the preconceived bias. The result is that a range of new approaches are now beginning to impact real-time fracking deployment and enable consistent fracking design adjustment “on the fly.” Over the past two years, this has meant there is an emerging line of sight, in early-stage execution to excellence and efficiency in real-time optimization and completion. (as well as a better understanding of physics, Fig. 1).
Understanding the difference that occurred between the drilling and completion journeys, it is not at all surprising that the drilling community was the first to create a relatively consistent roadmap that exists in the published literature. One result is the consistent delivery of best practices and a number of rapidly developed technology solutions.
In contrast, in the very vast hydraulic fracturing literature (several orders of magnitude more volumetric) we have multiple dead ends, broken promises, treatises of underperformance, and compelling dead ends that are all scattered and intertwined among the equally successful paths and advances.
This vast mix and quality of literature, while hugely relevant at the time, can now be just as frustrating and nearly impossible to work through for clarity and insight applicable to the present day.
However, a solution is potentially at hand as SPE’s new Hydraulic Fracturing Technical Section (HyFTS) offers to provide a number of best practice white papers that declutter the hydraulic fracturing roadmap. A first idea is to concentrate efforts on the advances and key ideas that have been hard achieved over the past 2 or 3 years and, above all, with a focus on the last 2 or 3 decades. The intention is to provide clear direction for those wishing to get to the front lines quickly and follow best practices closely.
There are a myriad of ways to do this effectively. Another suggestion is to consider the completion process broken down into a number of key steps, from cubic drilling strategies, through to reflux and cleanup (and everything in between).
With this stepwise breakdown, a useful approach may be to create a number of simple one-pagers that summarize current best practices, indicate the most recent industry publications, and any associated efforts that may currently be in progress. courses (for example, via test sites).
While it would be appropriate for the SPE HyFTS to lead the effort of compiling a page, the author(s) would be drawn directly from the most appropriate industry-recognized contributors.
Also, information on key articles could be effectively solicited from OnePetro statistics, comments from major conference committees (HFTC, URTeC, etc.) and other suggested sources. Following a fixed format, it is hoped that a suite (10-20) of these one-pagers can be quickly assembled by the fracking community and will provide SPE members and corps of engineers with a very useful to absorb the current state of fracking. unconventional completion engineering.
This is certainly a work in progress, but the HyFTS aims to move this initiative forward as efficiently as possible so that the hydraulic fracturing community can quickly benefit. We’ve all worked in very different ways over the past 18 months and we think new ways to ensure best practices are applied as quickly as possible are welcome.
Those wishing to contribute to this effort in any way can lend their support and participate within the HyFTS where all contributions are welcome (https://connect.spe.org/hydraulicfracturing/home).
Martin Rylance, SPE is the Discipline Lead and Distinguished Advisor for Fracking and Pacing at THREE60 Energy Ltd. Previously, he worked at BP and its joint ventures and partner companies for over 35 years. Having lived in 12 countries and pumped in 42, Rylance has international experience in fracturing and stimulation services, well control and multilateral drilling. He is the co-author of several books, including Modern Fracturing: Enhancing Natural Gas Production, and is the author of over 200 technical papers, articles and industry patents. Rylance was an SPE Distinguished Lecturer in 2007-2008, 2013-2014 and 2018-2019. He is an Emeritus Member of SPE and was awarded the SPE Completions Optimization and Technology Award for the SPE Gulf Coast Section in 2015 and the SPE International Award in 2021. Rylance is a member of the JPT editorial review board and director of the SPE hydraulic fracturing technical section and sits on several SPE committees. Rylance has a BS from the University of Salford and is a Chartered Engineer and Fellow of the Institute of Mathematics.