5% to 8% Recovery? Understand & Account for Variability, and Watch EUR Climb

GeoEngineering Connects Reservoir Characterization and Engineering to Production, with Validation through Microseismic Mapping

"The only thing constant is change." If we've learned anything over the past several years, it's that unconventional reservoirs seem to take great delight in challenging us in an equally paradoxical way. From Texas to China, Argentina to Kuwait, and North Dakota to Poland, shale reservoirs remind us that variability - whether by reservoir properties or completion and stimulation strategies, the microseismic response, initial production (IP), or EUR - is the constant we have to deal with.

Some US operators estimate recovery rates of 5% to 8% due to this challenge, but thanks to step changes in reservoir characterization modeling, horizontal drilling, new completion techniques and stimulation processes, and accurate microseismic data, operators can now do more than just scratch the surface of these resource-rich shale reservoirs. Above all, it is the integration of these discrete technologies that adds the most value.

Manage Reservoir Variability through Integration
Successful shale development requires a level of subsurface understanding that can only be achieved through an integrated workflow that turns key reservoir properties into a predictive model that precisely targets the areas that will yield maximum EUR when effective completion and stimulation campaigns are applied. This identifies where the bit needs to go, and is the framework from which all key decisions – from well placement, hazard avoidance, wellbore azimuth and inclination, and well spacing to completion technique, fracture spacing and treatment type – are made.

Since most of the effective permeability in a shale well is created during hydraulic frac stimulation, which is an engineering activity, integrated technology that addresses geology, geophysics and geomechanical rock properties, and the role of natural fractures is the key to targeting sweet spots before the fracture spread arrives at the wellbore.

"Integrated GeoEngineering™ provides a direct link between geoscience and engineering needs, including the ability to predict well performance with a high degree of confidence and pinpoint the richest targets before drilling begins, and then validate the findings in real time," said Jorge Machnizh, SIGMA³ CEO. "This helps operators optimize costs, and improve the outcome of each well."

Identify Sweet Spots & Estimate Horizontal Well Production
Using the proprietary CRYSTAL™ platform, SIGMA³ has delivered integrated 3D reservoir models to identify sweet spots and predict production of blind wells. By leveraging reflection seismic with geologic well data, production data and any available reservoir information, SIGMA³ delivers Shale Capacity™ models created from key reservoir properties, including natural fractures, brittleness, Total Organic Carbon Content, and porosity, to demonstrate reservoir heterogeneity and variable well performance. This workflow allows GeoEngineers to build models that connect microseismically derived Stimulated Reservoir Volume (SRV) to actual produced volumes in the context of reflection seismic, geologic and well log data. This 3D model helps identify subsurface properties that predict microseismicity, frac success, and ultimately production.

Clients have validated the results of the Shale Capacity models against known production in other nearby wells, and see consistently 80% to 90% confidence factors of the distribution and variability of the primary geologic drivers controlling production. Seismically and well log driven fractured reservoir characterization is now able to significantly increase the probability of drilling the best producing wells, while reducing the risk of drilling poor producers in both exploration and field development scenarios.

High-Confidence Event Detection & Location Accuracy Enables Meaningful Interpretation & Optimized Engineering
The relevance of microseismic events - how they can be used as a proxy to qualify the stimulated rock volume and ultimately production -- along with optimal well and frac design, is what transforms average wells into exceptional producers.

"Investing in the best downhole acquisition geometry and leveraging SIGMA³ innovations in 3D anisotropic velocity modeling and enhanced signal processing demonstrates high-confidence event locations delivered in the context of the earth model," says Machnizh. "Doing things right costs money, but it is far more expensive to waste money on costly non-productive frac stages by not implementing a comprehensive integrated science that can be validated in real time." In partnership with FracGeo, the company is now doing geomechanical modeling that can predict microseismicity before the microseismic data is acquired, and thus can help to better design the microseismic acquisition and completions engineering to improve success.

When it comes to engineering services integration, determining the best way to complete and frac is about production response. Operators maximize ROI by drilling the optimal number of wells and leveraging their trajectories to make the most of reservoir properties. SIGMA³ engineers have performed more than 35,000 stages, including on-site stimulation programs on major producing basins around the world. Optimized fracturing campaigns lead to fewer costly stages and better recovery.

Manage Reservoir Variability through Integration
Discrete solutions do not address the value of integrated reservoir characterization workflows that enable real-time frac data and microseismic events to be processed, interpreted and visualized in tandem with the earth models, well geometries, and geomechanical properties. This is the only way to manage variability and extract more from shale reservoirs.