Guest Editorial: Unconventional Development Approaches Health Check, and Where We Have To Go
Authors: Rylance Martin 
Published: December 2021

The direction of unconventional developments has been a roller-coaster ride, not only in the realms of financing and profitability, but very much in the technical execution of the well construction and the completion phases, too. This is particularly the case for those aspects relating to the completion and hydraulic fracturing operations.

There are few parties, I believe, that would disagree that the drilling com-munity rapidly delivered an extremely coherent and efficient learning curve, something that the completion/fracturing discipline has unfortunately been much slower to achieve.

This is not in the least surprising. Effectively extending conventional technologies and focusing on key requirements (i.e., getting from point A to point B) worked well for drilling teams. In a commendable and efficient manner, they were able to readily deploy and incrementally learn in an almost linear fashion. This achieved remarkable delivery records across all unconventional plays.

Completions however, namely hydraulic fracturing, has been a very different journey and involves solving a very different problem, one with many more variables, inherent complexities, and multiple degrees of freedom.

With each unconventional play potentially being distinct (just as with drilling), these differences can, however, extend to impactful areal trends and features within the plays, as well as subtle variations along individual lateral wellbores. For example, unlike drilling, the form (and even sequence) of an offset wellbore completion can easily affect the completion operations in the current wellbore.

It is quite 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, something that appears to have been understandably addressed in recent years. However, there was also a likely inherent engineering bias in the industry’s fracturing staff engineers.

The bulk of the industry engineers had entered unconventionals off at least 2 decades of well understood, well defined, and highly effective physics-based analysis of conventional planar fracturing operations.

Indeed, in some areas this fallacy continues. For example, proppant selection is ostensibly performed based on long-established criterion set in place in the 1970s and 1980s, and wholly appropriate to planar fracturing. Whereas the reality is that proppant plays multiple very different roles in unconventionals, bridging, plugging, wedging, diverting, etc.

This has led to a “tearing up of the rule book” situation within the sector (that is ongoing) as poorer-quality sands and micro-/nanoproppants find applicability, as well as quality ceramics for a strategic place in the fracture. Yet, you may ask any frac engineer to select proppant for unconventionals and they will almost immediately request data on performance at 2 lb/ft2, as though we are flowing through proppant packs across the entire created geometry.

This significantly enhanced level of complexity has led to a general failure of the linear model in terms of effectiveness in progressing optimum completion solutions. As a result, the early years of unconventional completion learning were largely “lost” in this linear way.