New Oil Recovery From an Old Field: A Case Study in the Western Desert of Egypt
Authors: Denney Dennis 
Published: February 2015

This article, written by Technology Editor Dennis Denney, contains highlights of paper SPE 99401, "New Oil Recovery From an Old Field: A Unique Case Study in Badr-1 Concession, Western Desert, Egypt," by M.I. Youssef, SPE, Badr Eldeen Petroleum Co., prepared for the 2006 SPE Europec/EAGE Annual Conference and Exhibition, Vienna, Austria, 12–15 June.

A recent simulation study on the Kharita reservoirs of the Badr-1 (BED-1) field showed underestimated volumes of the original oil in place (OOIP). With no further activities, predicted performance indicates total ultimate recovery from the Kharita reservoirs will be 53.5% of the OOIP. All future sidetracks and new locations were terminated on the basis of limited remaining reserves as per the preliminary simulation predictions. Because of inconsistencies between the current average oil-production rates and the large volumes of cumulative oil produced, and combining the indicated pressure performance with the driving mechanisms, a reservoir-management revision and performance-review study were made to explain discrepancies and inconsistencies of the Kharita reservoirs performance in BED-1 field. The focus was to understand reservoir performance rather than just obtain a history match.

Introduction

In this field study, a different form of the material-balance equation was used, and history matching was performed on the reservoir pressures, oil rates, water/oil ratios, and gas/oil ratios, as well as on the aquifer strength and water-influx volumes, reservoir free-gas volumes, and remaining volumes of the unflooded recoverable oil with simultaneous balancing of the total-system reservoir pore volumes, at any time during any flooding/depleting stage, with the subset option of estimating and predicting bypassed oil volumes behind the flooding front. This work created a reliable representative water/oil relative permeability data set from the production performance. A simplified approach to the water-movement model was developed for the Kharita layers that were already perforated and producing oil and water. The use of oil-saturation estimates under combined driving mechanisms for the average total-system reservoir residual-oil saturation showed the most likely range of remaining recoverable oil. The main producing horizons of BED-1 field are in the Kharita reservoirs. These reservoirs contain more than 60% of the total BED-1-field OOIP and more than 90% of its ultimate recovery.

Purpose and Objective

The purpose was to improve oil recovery by performing a series of serious attempts to understand the complicated performance of wells in the BED-1 field and the Kharita reservoirs. After building a geological/static model for estimating the OOIP and building a dynamic model to simulate pressure and production performance, reservoir-management approaches and techniques were used for a waterdrive-reservoir case study. The main objectives of this work were to review, analyze, and evaluate wells and reservoir performance to revise the current estimates on the OOIP; to revise the ultimate recovery factor; to establish a confirmed, most-likely range of the remaining oil recovery by the life-end of the reservoirs at the economic limit (EL) and the abandonment pressure; and to submit the predicted performance of the Kharita reservoirs as a base case with no further activity and under different field-development plans (FDPs).