Ambastha

Papers in this issue of the SPE Res Eval & Eng primarily focus on numerical simulator enhancements, resource estimation/production optimization techniques, and improved/enhanced oil recovery (IOR/EOR) techniques. The following is a brief outline of the papers in this issue.

"Feedback Controllers for the Simulation of Field Processes" presents a generic controller framework within a reservoir simulator that enables the usage of different kinds of controller algorithms for managing a variety of field processes. Traditional proportional, integral, derivative (PID) controllers, as well as linear and nonlinear fuzzy controllers are considered. The advantages and disadvantages of the approaches are discussed. "A Quantitative and Qualitative Comparison of Coarse-Grid Generation Techniques for Modeling Fluid Displacement in Heterogeneous Porous Media" evaluates three grid generation techniques: permeability-based (PB), flow-based (FB), and vorticity-based (VB) gridding as applied to a number of 2D heterogeneous models with simulation of two-phase flow on the constructed grids. The paper shows that FB and VB gridding are superior to PB gridding. Although performance of FB and VB gridding is comparable in many cases, VB gridding yields more accurate global and local results and reduces application of sophisticated upscaling techniques and full-tensor permeability upscaling. "Embedding a Petroelastic Model in a Multipurpose Flow Simulator to Enhance the Value of 4D Seismic" describes the calculation of seismic attributes such as P-wave and S-wave velocities and impedances, dynamic and static Young’s moduli, and dynamic and static Poisson’s ratios within a flow simulator. Examples illustrate how to use the petroelastic model to facilitate the integration of 4D seismic and reservoir flow modeling. "Improved Prediction of Oil Recovery From Waterflooded Fractured Reservoirs Using Homogenization" derives a numerical model to solve full 3D integro-differential equations in a field reservoir simulation. This model is termed boundary-condition (BC) approach. This paper shows a comparison of results from the BC and Warren and Root approaches to simulate waterflood performance for fractured reservoirs. "Ensemble-Based Closed-Loop Optimization Applied to Brugge Field" applies optimization techniues to a large-scale SPE benchmark study. Using covariance localization, covariance inflation, regularization, normalized saturations, and global parameters such as relative permeability curves and initial oil/water contact, this paper describes how the resulting combination of ensemble-based data assimilation and optimization achieved a net present value within 1% of the value obtained by the test organizers with known geology. "Probabilistic Aggregation of Oil and Gas Field Resource Estimates and Project Portfolio Analysis" presents a statistically-robust method based on multivariate skew-normal distributions for aggregation of resource estimates for multiple fields that appropriately uses expert opinion. Using two integrated-project examples, this paper also introduces new methods for estimating a measure of dependency between the resource estimates of individual fields. "Integrated Data Analysis and Dynamic Fracture Modeling Key To Understand Complex Waterflood: Case Study of the Pierce Field, North Sea" argues that integrated analysis resulted in a consistent explanation of the observed reservoir behavior. This integrated analysis approach has resulted in changes in the day-to-day water-injection management and is deemed to play a key role in longer-term development strategies "Hydrocarbon Production Optimization in Fields With Different Ownership and Commercial Interests" discusses how total oil and gas production from main and satellite fields could be optimized using the processing facility at the main field. This paper compares two production strategies. The first production strategy optimizes locally at distinct time intervals. In the second production strategy, a fixed weight is assigned to each reservoir with weights optimized from a life-cycle perspective. "Saturated Steam Pressure Drop in Flow Through Porous Media" provides a simple steady-state method for estimating the pressure drop for steam vapor flowing at a constant mass rate through porous media. This method eliminates the need for steam tables within the applicable pressure range (10–2,900 psia). "Miscible Interaction Between Matrix and Fracture: A Visualization and Simulation Study" studies matrix/fracture interaction using 2D glass-bead models and a commercial compositional simulator. In the experimental setup, first-contact miscible solvent (pentane) was injected into the fracture and the flow distribution was monitored using an image acquisition and processing system. In the simulation study, saturation distribution in the matrix was matched to experimental data. The key parameters in the matching process were the effective diffusion coefficients and the longitudinal and the transverse dispersivities. The study reported in "How the In-Situ Combustion Process Works in a Fractured System: 2D Core- and Block-Scale Simulation" is based on a fine-grid, single-porosity, multiphase and multicomponent simulation using a thermal reservoir simulator. Both 1D and 2D combustion simulations were carried out. The nature (i.e., oil production rate, saturations distribution, shape of the combustion front) of combustion at core scale was different from that in a single block with surrounding fracture. The important characteristics of different zones (i.e., combustion, coke and oil zones) at block scale were studied and some preliminary guidelines for upscaling are presented. "Field-Scale Analysis of Heavy-Oil Recovery by Electrical Heating" studies the applicability of electrical heating for two heavy-oil fields (Bati Raman and Camurlu) in Turkey. Experimental data on in-situ viscosity reduction during the heating process with and without using iron powder are presented first followed by numerical simulation results of electrical heating. "Enhanced Oil Recovery Pilot Testing Best Practices" outlines a staged approach to EOR evaluation and focuses specifically on pilot testing best practices. These best practices were derived from more than 50 field pilot tests covering the full range of EOR processes. "Use of X-Ray CT To Measure Pore Volume Compressibility of Shaybah Carbonates" describes a new technique involving dual-energy computerized tomography (CT) scanning to obtain the pore volume compressibility values, which were compared against the conventional triaxial cell generated data and published results on cores taken from the same reservoir. Some of the advantages of the new CT based analysis technique include the generation of multiple pore volume compressibility curves from the same plug (a band of data, each at a different slice location), the "visualization" of the changes, the possibility of using either hydrostatic or triaxial cells to make the test more case specific, and the possibility of measuring permeability under different stress conditions before, during, and after the test.

As you study your favorite paper(s) to enhance your own knowledge and/or apply in your work activities, please recognize that SPE welcomes further "Discussion" of any of the papers published in any SPE journal, including this one. Therefore, please feel free to submit discussion of a paper either online or by mail to SPE.

—Anil Ambastha, Chevron