Executive Summary

This issue of SPE Reservoir Evaluation & Engineering features 25 papers that represent an excellent cross-section of the latest advancements in trending technologies within the Reservoir Evaluation and Engineering community. Eleven papers are related to thermal, heavy-oil, chemical, and miscible recovery processes; four papers are focused on reservoir management; and ten papers are related to reservoir-characterization methods in the areas of rock mechanics, petrophysics, tracer studies, and pressure-transient analysis.  In addition, 11 of these papers are leading-edge contributions to SPE publications in the development of unconventional resources, which is attracting global interest in the industry. Below is a brief description of the papers presented in this issue.

Thermal Enhanced Oil Recovery. Successful Steamflood Pilot in 1st Eocene Carbonate Reservoir of Wafra, PZ Mitigates Key Technical Uncertainties provides learnings from the first, large-scale steamflood pilot that was successfully completed in a heavy-oil carbonate field in the Middle East.

Models of Thermal Enhanced Oil Recovery in Fractured Reservoirs introduces thermal models for steam and hot-water injection into a fractured diatomite or shale reservoir and investigates key recovery factors that include reduced fracture spacing, increased matrix permeability, and increased injection temperature.

Heavy Oil Recovery. Solvent-Based and Solvent-Assisted Recovery Processes: State of the Art provides a review of projects using solvents alone or in combination with steam for enhancing heavy-oil recovery.

Experimental Evaluation of Colloidal Nanosilica for Improving Bitumen Recovery From Mined Oil-Sand Ore demonstrates that colloidal nanoparticles can improve the efficiency of the many stages of the bitumen-extraction process—from bitumen separation to clay-wettability alteration.

Chemical Enhanced Oil Recovery. SmartWater Synergy With Chemical Enhanced Oil Recovery: Polymer Effects on Smartwater investigates the synergies between polymer and smartwater flooding for viscous-oil recovery in carbonates, and demonstrates that smartwater combined with polymer can improve oil recovery and reduce polymer concentrations.

Lessons Learned From Alkali/Surfactant/Polymer-Flooding Field Tests in China provides insight and data on alkali/surfactant/polymer flooding from 30 field tests in China.

Development of a High-Temperature-Resistant Polymer-Gel System for Conformance Control in Jidong Oilfield introduces an in-situ polymer-gel system developed for the Jidong field in China that has the potential to improve conformance at extremely high temperatures.

Preformed Particle Gel Injection Chased by Low-Salinity Waterflooding in Fractured Carbonate Cores demonstrates that low-salinity water injection after gel placement can improve gel propagation into fractures and increase oil recovery because of the reduction in gel strength (apparent viscosity) that is achieved by using lower brine concentrations.

Miscible Flooding. A Comprehensive Model for Investigation of Carbon Dioxide Enhanced Oil Recovery With Nanopore Confinement in the Bakken Tight Oil Reservoir presents an effective model to evaluate well performance for a CO2 huff ’n’ puff process in tight oil reservoirs with nanopore confinement and complex-fracture geometries as demonstrated in the Bakken field.

Laboratory Evaluation of Different Modes of Supercritical Carbon Dioxide Miscible Flooding for Carbonate Rocks investigates several supercritical CO2 injection processes in carbonates under reservoir conditions that include continuous CO2 miscible flooding, water-alternating-gas (WAG) injection, and tapered-WAG injection.

Analysis of Secondary and Tertiary High-Pressure Gas Injection at Different Miscibility Conditions: Mechanistic Study provides insight into the effect of water shielding on oil recovery in miscible gas injection processes at high pressures and temperatures.

Rock Mechanics. Two-Scale Geomechanics of Shale introduces a methodology for estimating static elastic properties of shale formations from drill cuttings.

Generalized Methodology for Estimating Stress-Dependent Properties in a Tight Gas Reservoir and Extension to Drill-Cuttings Data introduces a more accurate methodology for estimating stress-sensitive rock properties, such as porosity, permeability and compressibility, in tight formations that can be applied to drill cuttings.

Reservoir Management. Concerns and Clarifications for Drilled Uncompleted (DUC) Wells in the Williston Basin provides insight into key challenges that can affect the productivity of drilled uncompleted wells when they are eventually completed that include well interference, hydrocarbon drainage, zone connectivity, and well spacing.

Integration of 4D Seismic in Steam-Assisted-Gravity-Drainage Reservoir Characterization presents a practical methodology for integrating 4D seismic into the reservoir characterization of the steam-assisted-gravity drainage Surmont project.

Unlocking the Potential of the Monterey Shale Resource: An Analysis of Geological Characteristics, Completion Techniques, and Production Behaviors introduces a combination of EOR methods for improving oil recovery from both nonfractured and fractured zones of horizontal wells in California’s Monterey Shale.

Production-Performance Analysis of Composite Shale-Gas Reservoirs by the Boundary-Element Method introduces the boundary-element method as a solution technique for a multifractured horizontal well in a composite shale-gas model with multiple flow mechanisms.

Tracer Studies. A Step Change for Single-Well Chemical-Tracer Tests: Field Pilot Testing of New Sets of Novel Tracers provides the results of a field trial for a class of new reacting tracers that require significantly smaller concentrations of chemicals than traditional tracers used in single-well chemical-tracer tests.

Extension of Capacitance/Resistance Model to Tracer Flow for Determining Reservoir Properties presents the integration and application of tracer models, based on miscible displacement theory, into a capacitance/resistance model that enables the estimation of dispersion and Koval factors in addition to interwell connectivity and drainage volume. 

Formation Evaluation. Novel Method for Evaluating Shale-Gas and Shale-Tight-Oil Reservoirs Using Advanced Well-Log Data introduces a novel well-logging method for determining more-accurate total porosities, fluid volumes, and kerogen volumes in shale-gas and shale-tight-oil reservoirs by accounting for the effects of light hydrocarbons and kerogen on the log response.

Interpretation of Nuclear-Magnetic-Resonance Response to Hydrocarbons: Application to Miscible Enhanced-Oil-Recovery Experiments in Shales highlights the importance of running NMR tests at reservoir temperature as a basis for estimating movable hydrocarbons.

Capillary Pressure and Wettability Indications of Middle Bakken Core Plugs for Improved Oil Recovery demonstrates through laboratory experiments the potential for low-salinity waterflooding/soaking to improve oil recovery by molecular diffusion/capillary osmosis from low-permeability formations saturated with high-saline brine.

An Innovative Laboratory Method to Measure Pore-Pressure-Dependent Gas Permeability of Shale: Theory and Numerical Experiments proposes an innovative laboratory method to measure shale-gas permeability as a function of pore pressure, a key parameter for characterizing and modeling gas flow in a shale-gas reservoir.

Pressure-Transient Analysis. Determination of In-Situ Reservoir Absolute Permeability Under Multiphase-Flow Conditions Using Transient Well Testing introduces a new method that uses transient well testing to determine in-situ absolute permeability of the formation when three phases of fluids are flowing simultaneously in the reservoir.

Buildup-Pressure Extrapolation of a Heterogeneous Reservoir: Application of the Crump and Hite Method to a Real Field Case presents a successful application of the Crump and Hite method to determine average reservoir pressure for a pilot production test offshore Brazil.

Jasper Ring, SPE Res Eval & Eng Executive Editor,