On a conference call in 2011, the always eloquent Clay Williams of National Oilwell Varco (then CFO, now CEO) said:
The unconventional shale model is utterly unlike drilling a generation ago, which saw fleeting glimpses of precious darcy reservoir rock here or there, elusive four-way closure, a rare and fortuitous geologic ancestry which bestowed the structure with charge. When the stars aligned for the lucky explorer, it was elegance. Shale drilling is not elegance. Shale drilling is a brute force enterprise. It hurls massive iron and horsepower at a plentiful, fairly pedestrian rock in exchange for a secure and protected production volume. It is underground shock and awe that makes oil and gas give up and surrender. That is the trade-off — certainty of production volumes in exchange for oilfield iron eaten with voracity.
If that doesn’t make you want to go frac some low permeability rock, something’s wrong. In all seriousness though, Clay perfectly articulated the industry’s state of mind in the early innings of unconventional oil development.
At the time, large stage fracs in tight oil plays had only been conducted on a mass scale for a few years – shale gas completion methods were being imported by operators in tight oil formations. Optimization was still on the horizon.
The “brute force enterprise” Clay referred to is basically the combination of long horizontal wells drilled from pads and millions of pounds of sand pumped downhole by high horsepower frac spreads. Increasing the amount of brute forced applied in unconventional basins has pushed well performance higher since Clay’s commentary. This chart of Delaware well progression from Noble shows how enhanced completions have been linked to sand intensity (a brute force element).
Source: Noble Energy
Brute force is still key to unconventional completions, but shale moves fast and underground shock and awe alone is no longer the endgame. Today, brute force is merely the ante – the minimum requirement to sit at the tight oil table. Shale drilling has taken an undeniable turn towards higher degrees of sophistication.
The complexity shrouding hyrdrocarbon stored in nano-darcy rock is the barrier to elegance. Today, innovators are increasingly focused on finding new ways to enhance sub-surface understanding. Technologies are emerging to empower the industry to design around source rock features we cannot yet fully comprehend – these technologies are breaking down the barrier to elegance.
It’s Rocket Science Now
Operators have pushed brute force factors towards diminishing return boundaries. Now they are turning to innovation to harness and focus brute force in new ways to enhance hydrocarbon recovery from heterogeneous micro- and nano-darcy rock.
No where was this shift more evident than at the Darcy Completions Forum in Houston late-last year. The event was hosted by Darcy Partners, a platform for scaling adaptive technologies in O&G. Darcy Partners is a firm founded by smart O&G technologists that understand the structural shift occurring in E&P (and the innovators behind it) better than most.
As we sat in the room, 35 senior completions managers, engineers and decision makers evaluated 11 early-stage innovators. The dialog felt more like something you’d hear at NASA than the talk you might expect to hear above the rumble of frac trucks.
The presented technologies ranged from vibration sensors downhole to measure rock strength, to Electromagnetic signals to locate frac liquid and proppants to DNA tracers to artificial intelligence optimization of frac designs.
Research shared with Infill Thinking by Darcy Partners outlines three major (and progressively more advanced) approaches taken by the completions industry to drive efficiency. 1 and 2 are old stories now; 3 is where we are headed:
- Higher Intensity Fracs. Shale operators began high intensity frac campaigns with more stages and higher proppant volumes yielding greater drainage efficiency. This has been tested and pushed, and may reach a period of diminishing marginal returns or environmental resistance. Infill Thinking take: after drilling rig efficiency gains dominated headlines in 2012 and pad drilling adoption gained traction in 2013, operators turned to higher intensity fracs en masse during 2014. Downhole intensity dominated the conversation during 2014 and was still a theme for the fewer wells completed thruought the downturn. This approach is a relatively simple escalation of brute force.
- Optimized Geometric Fracs. Through trial and error and in some cases using advanced analytics engines, some operators take all the public and internal data on reservoir and completions parameters to generate the best recipes. These methods, sometimes combined with scientific models, tend to be inconsistent and error prone due to highly heterogeneous subsurface characteristics in the shale plays. Infill Thinking take: this a hybrid brute force / science model. It is an early turn towards elegance that has showed some promise but hasn’t been fully tested yet. Our sense is that the jury is still out and consensus is divided on value add.
- Engineered Completions.Traditional geometric completion methods do not fully tackle the low percentage of producing stages. Many operators have started to experiment with engineered fracs by understanding the geomechanical properties of the reservoir along the wellbore and hence placing the frac stages along the areas with the highest production potential. A fully coupled geomechanics and fluid flow model with hydraulic fracture capability is the future.
Since Clay’s characterization of shale drilling in 2011, millions of man hours have been spent by the brightest minds in petroleum engineering thinking about a singular question: how do we optimize recovery rates and well efficiencies in heterogeneous low permeability reservoirs?
Shale drilling has become a lot smarter as a result. Intelligence breeds elegance, and finding elegance hinges on improvements in sub-surface understanding and visibility.
Hossein Rokhsari, partner at Darcy Partners, concluded the one day intensive workshop with 12 E&P operators around the table: “We are all waiting for the science of the nano-darcy reservoir to catch up (a fully coupled geomechanics and fluid flow model with hydraulic fracture capability). In the meanwhile we have to get more and better data so we can ‘see’ the reservoir and what we do to it. Many of the technologies that we showcased today, are providing one slice of reality, not the whole truth, at an order of magnitude lower cost than solutions provided to you by your existing suppliers. A few of these technologies combined can provide a pretty realistic picture your reservoir. And once you look at this data in real time, you can ‘play’ with the formation with a joy stick even if you don’t fully understand the nano-darcy science.”
Nano-darcy rock will always require the brute force of powerful iron, but technologies that provide sub-surface visibility are at the forefront of the industry’s quest for elegance.
Next week, look for an update from Infill Thinking on five themes in completions innovation which we believe will help shape technology trends in 2017.