Executive Summary

The last issue of Volume 22 of SPE Reservoir Evaluation & Engineering comes with a lineup of 28 papers. I am extremely glad that we continue receiving excellent manuscripts in large numbers issue after issue. The papers cover a diverse number of topics in reservoir engineering, petrophysics, machine learning, and oil and gas economics, among others. This time, we continue featuring papers on the spotlight of the trending topic of machine learning and data analytics (MLDA).

I would like to welcome new associate editor Adolfo D’Windt. Adolfo brings more than 20 years of experience in reservoir engineering, pressure-transient analysis, and reservoir characterization. The staff and editorial committee of the journal truly appreciate the contribution of our volunteers to step up as associate editors, technical reviewers, and authors.

Below, please find a brief summary of the papers comprising Issue 4, Volume 22 of SPEREE.

SPOTLIGHT: Machine Learning and Data Analytics in Petroleum Engineering

This section presents four papers that describe the application of MLDA for well data integration and production prediction, shale-gas supply-chain optimization, sonic log prediction for geomechanical characterization, and applications for recovery-factor forecasting for exploration.

Characterization of Unconventional Reservoirs

Understanding the pore-scale structure and fluid transport in tight rocks is fundamental to optimal development of unconventional resources. This section brings you five papers. The first paper deals with geochemical applications to identify potential zones with movable oil in shale reservoirs. The second paper studies the gas mass transport model for microfractures. The third paper uses material balance to determine original gas in place in shale formations, whereas the fourth article studies the influence of fractures for more-accurate laboratory measurement of shale matrix permeability using a modified gas-expansion method. Finally, the last paper of this section presents an interesting case study of the Eagle Ford and Pimienta shale formations in Mexico.


The three papers in this section deals with laboratory measurements on rock samples. The first paper quantifies the effect of thermal maturity of kerogen on its wettability, the second paper presents the results of quantitative monitoring of cleaning time and wettability alteration of carbonate rocks during Soxhlet cleaning, and the last paper measures gas relative permeability and its evolution during water imbibition in unconventional reservoir rocks.

Pressure Transient Analysis

This section features two papers of well testing in unconventional reservoirs, rate-transient analysis based on the power-law behavior for Permian wells and a review paper on well-testing challenges in unconventional and tight-gas-formation reservoirs presenting solutions to such challenges in various unconventional plays.

Interpretation and Prediction of Fractures

Interpretation of fractures from image logs is critical to understanding wellbore stability and to assessing the presence of natural fractures that may improve reservoir performance. Little has been done in quantitative prediction of fractures. The two papers in this section bring some light to this complicated field by validating predicted fracture corridors by statistical comparison with well data and presenting methods for estimating fracture abundance and size from borehole observations.

Enhanced Oil Recovery

In this section, four papers are included that describe different research projects on enhanced-oil-recovery (EOR) methods. They include

  • Improving chemical-EOR simulations and reducing subsurface uncertainty using downscaling conditioned to tracer data
  • Improved hydrocarbon recovery using mixtures of energizing chemicals in unconventional reservoirs
  • An integrated carbon-dioxide-foam EOR pilot program with combined carbon capture, utilization, and storage in an onshore Texas heterogeneous carbonate field
  • Bubble-population-balance modeling for supercritical carbon dioxide foam EOR processes from pore-scale to core-scale and field-scale events.

Reservoir Simulation

Numerical reservoir simulation allows us to understand how a reservoir behaves by using first principles and physics of fluid flow. This section brings you a robust uncertainty quantification through integration of distributed-Gauss-newton optimization with a Gaussian mixture model and parallelized sampling algorithms and a physics-based fluid flow modeling of liquids-rich shale reservoirs using a 3D three-phase multiporosity numerical simulation model.

Stochastic Production Optimization

Three papers describe new approaches for dynamic production optimization. The first paper discusses probabilistic mapping of well performance in unconventional reservoirs with a physics-based decline-curve model, the second paper shows the application of ensemble variance analysis in the development of the Wheatstone field startup strategy, and the last article of this section combines decline-curve analysis and geostatistics to forecast gas production in the Marcellus shale.

Oil and Gas Economics and Uncertainty

The economic section of this issue presents two relevant articles. The first paper makes use of stochastic decision trees to assess reservoir and economic uncertainties for recovery strategy selection and the second paper introduces a practical reservoir-management strategy to optimize waterflooded pools, making use of minimum capital.

Heavy Oil

The only paper of this section describes an empirical oil, steam, and produced-water forecasting model for steam-assisted gravity drainage (SAGD) with linear steam-chamber geometry. The model allows the use of commercial SAGD production data for the forecasting process. Predictions are validated in the Jackfish project in Alberta, Canada, and numerical simulations.

As in every issue, the editorial board has made every effort to bring you a robust selection of manuscripts from industry and academia. All papers were carefully reviewed by at least two technical reviewers under the coordination of an associate editor. However, conclusions and interpretation stemmed from these papers are opinions and observations of the authors. I would like to express my appreciation to the technical reviewers who selflessly dedicate their time to perform outstanding reviews to maintain the quality of our journal.

We at SPE always welcome further discussion from our readers. We look forward to receiving your comments and suggestions.

This is my last executive summary, as my term as executive editor concluded this November. I want to wish the best to new executive editor, Turhan Yildiz, who will be in charge of the formation evaluation side of the journal for the next 3 years. I also want to express my gratitude to Dean Oliver, former Editor-in-Chief, and Russ Johns, current Editor-in-Chief, for their leadership and mentorship during the last 3 years. Finally, a big thank you to the SPE Editorial Office’s staff that guided me and kept me up-to-date during my tenure.

Hope you enjoy these outstanding papers! 

Jesús M. Salazar, Executive Editor of SPE Res Eval & Eng,
Marathon Oil, Houston