|MSE||Harder rock||Correlates With|
|High||Harder rock||Lower porosity|
Shorter fracture length
Increased breakdown pressure
Increased brittleness index
|Low||Softer Rock||Higher porosity|
Longer fracture length
Decreased breakdown pressure
Decreased brittleness index
How MSE is Used for Engineered Completions
MSE information is used to modify stage and cluster placement (physical stage design), as well as treatment plans. While modifying treatments based on MSE is still an evolving art, designing physical stage attributes based on MSE data is well understood science.
MSE-based completion design leverages the fact that when all of the clusters in a stage are in similar rock, you increase cluster participation (more clusters producing hydrocarbons) and get better fracture propagation (increased aggregate exposure to the reservoir). This occurs because perforations in the same rock all fracture and propagate at the same treating pressure.
There are two ways to get the perforation clusters in rock with similar MSE ranges. The most obvious is to adjust cluster placement to target similar rock within each stage. The other is to adjust actual stage lengths or placement so that each stage has consistent rock. This might seem like a lot of manual labor to tune each stage and each cluster. Purpose-built software is required to automate these tasks for improved efficiency.
Vendors and operators have run tests comparing nearby wells completed using geometric designs against MSE-based engineered completions. While specific well results vary, MSE-based engineered completions have thus far demonstrated an average 19% increase in production versus wells with geometric completions. We believe that further improvements in design tools will enable cluster placement that is more true to MSE measurements, resulting in superior and more repeatable results.
There are additional cost advantages to MSE-based engineered completions. By placing perfs in like rock, you reduce the need for diverter to temporarily occlude the fractures that form at a lower treating pressure, so that harder rock can fracture. Diverter requires additional material cost and pump time, which is eliminated by MSE-based completion designs.
Another advantage is by reducing treating costs in poor quality or out of zone rock. In a geometric design, all rock is designed and treated the same way. If, for example, you find that the wellbore veers out of zone for one or more stages, you could isolate those stages and use a less costly treatment. For example, if you had a single out of zone stage, you might reduce proppant by 50% and save approximately $30,000. If you are out of zone for multiple stages, the savings could grow considerably, without negatively impacting your production.
Practical Challenges to MSE-based Engineered Completions
While Mechanical Specific Energy is a powerful piece of information for engineered completions, there are practical challenges that must also be addressed in order to maximize your results. These challenges arise where operations (what is practical) intrudes on science (theory).
MSE is calculated based on the drillbit at depths measured by the drill string. However, perfs are shot using wireline which stretches, and the stretch increases with wireline length. The actual stretch will differ from the heel to the toe. Since MSE has one foot precision and wireline might be off by 10 feet at the toe, this must be addressed or you might put perfs in disparate rock, resulting in subpar results, especially in the toe intervals where the stretch is most pronounced.
Shooting Perfs on the Fly
If the reservoir permits, the wireline company should avoid shooting perfs on the fly, because this method decreases the precision of perf placement, versus the stop and shoot method. However this is often dictated by the reservoir.
You might have a perfect MSE-based design. Then you give it to the wireline company who starts shooting perfs and runs into maybe 6 collars per stage. If the operator dictates a 4 foot buffer per collar, 2 on either side, this could mean 24 feet that cannot be perforated. This could alter the calculation of the predominant rock type in that stage. Even worse, if the collar locations are not considered in the design phase, the wireline operator onsite may simply shift cluster positions by up to 4 feet each. This can have a cascading impact on other perf locations, due to minimum spacing, or it may simply put those perfs in dissimilar rock types. In either case, you can quickly undermine your engineered design and deliver sub-optimal results.
Natural fractures can also undermine the goals of an engineered completion and they must be addressed as part of the design process.
The good news is that these challenges can be addressed and DeepData’s Completion Design tool addresses them. One of my favorite quotes is quite applicable here: “The difference between theory and practice: In theory, there is no difference. In practice, there is.”
MSE: One of Many Data Sources Powering Engineered Completions
MSE is a powerful and high-resolution way to characterize the geology along your completable lateral, but it is by no means the only approach. Openhole logging can provide very valuable information. You can also leverage cutting analysis (XRF, XRD, SEM, TIC, TM, etc.). Some labs will even blend rock properties with curves such as Gamma Ray, to generate pseudo-sonic curves. Cutting analysis, like MSE, is non-invasive and relatively low-cost.
The ultimate value comes from matching the actual measured results against the rock types, designs, and treatments. There are three primary mechanisms for measuring actual results. One method is via pressure graphs from treatment, this is where the reservoir speaks to you. Another approach is measuring the hydrocarbon production along the lateral. This can be done through a variety of methods, tracers (stage level insight), surface-based fluid measurement (e.g. Deep Imaging), fiber-optic (casing-attached or in-hole), and production logs (various methods). The final, and lowest resolution approach, is to simply measure production at the wellhead. Unlike the other methods, well-level production doesn;t provide insight into which stages and clusters are contributing and to what degree that contribute.
Vendors Providing MSE-Based Completion Design
We appreciate your insight on this list (and this page), please email new vendors to firstname.lastname@example.org
NexTier (Formed by the merger of Keane and C&J)
FractureID (based on accelerometer tool added to the BHA)
Software Tools for MSE-Based Completion Design
Engineered (or GeoEngineered) Completions are the future; and that future is here now. MSE is a low-cost and effective tool for characterizing rock properties. By placing the perf clusters for each stage in like rock, you get a consistent breakdown pressure across the stage, better fluid and proppant distribution, and better exposure to the reservoir. As a result, you get better production. MSE is one of many data sources that will power engineered completions in the future. Continuous improvement of well economics will be ultimately be driven by machine learning that aggregates all sorts of data inputs and compares those against actual results. Starting early, building experience, and getting your data organized for machine learning will determine E&P winners and losers in the near future.