Development of Improved-Hydrocarbon- Recovery-Screening Methods
Authors: Denney Dennis 
Published: February 2015

This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper SPE 129768, ’Development of Improved-Hydrocarbon-Recovery- Screening Methodologies,’ by Jasper L. Dickson, SPE, and Alana Leahy- Dios, SPE, ExxonMobil Upstream Research, and Philip L. Wylie, SPE, Mobil Producing Nigeria, prepared for the 2010 SPE Improved Oil Recovery Symposium, Tulsa, 24-28 April. The paper has not been peer reviewed.

An improved-hydrocarbon-recovery (IHR) -screening method was developed that can screen and prioritize a large number of reservoirs for various IHR processes and then generate preliminary flow-stream forecasts by use of generic-sector modeling and proxy simulation. This process enables quick screening for a variety of enhanced-oil-recovery (EOR) techniques by use of reservoir-rock/-fluid properties and technical-/economic-screening criteria, and then ranks the EOR options quantitatively. 

Introduction

With the increasing maturity of conventional oil resources and limited volumes of discoveries of new conventional resources to replace production, IHR can be key in an oil company’s reserves-base growth. Therefore, effective tools and methodologies must be developed to screen and prioritize assets for IHR opportunities. In addition to identifying the most appropriate IHR process, it is equally important to predict the reservoir performance. IHR encompasses both improved-oil-recovery (IOR) (e.g., waterflooding and immiscible-hydrocarbon-gas injection) and EOR (e.g., miscible gas, chemical, and thermal) processes.

This IHR-evaluation workflow is shown in Fig. 1. The first step is to identify the most promising injection type and processes for a given reservoir and to complete preliminary screening economics to ensure feasibility. This initial-screening step is followed by a more-in-depth investigation (e.g., laboratory studies, mechanistic simulations, and additional data gathering) of the most-promising processes. When a proposed project shows potential for field implementation, pilot tests may be conducted to resolve key uncertainties. Additional simulations or laboratory studies may be required after pilot-test completion, as indicated by the feedback loop in Fig. 1. The final steps consist of developing the commercial-project plan and implementing the necessary surveillance program.

Fig. 2 summarizes the entire work-flow: IHR screening and prioritization, sector modeling and type-curve generation, and proxy simulation and flow-stream generation. Each step is detailed in the full-length paper.

Screening and Prioritization

Screening Algorithm. The automated algorithm compares key properties of a given reservoir to screening criteria of various processes. Then, it generates a list of most- to least-recommended processes on the basis of a point-allocation system for each screened property. Any number of reservoirs can be screened simultaneously.

Collect Reservoir and Fluid Data. Reservoir and fluid data for the reservoirs of interest are collected in a database. Analog data are used in the screening tool when specific reservoir data are not available. For most properties, analog values are obtained from proved and probable weighted averages on the basis of a user-defined region, basin, subbasin, reservoir, zone, period, or epoch.