Steamflood Piloting the Wafra Field Eocene Reservoir in the Partitioned Neutral Zone, Between Saudi Arabia and Kuwait

Abstract

The concept of steamflooding the Wafra Eocene dolomite reservoir originated in various studies conducted in the 1980's. In 1999, a comprehensive EOR study and Eocene huff-n-puff pilot suggested that steamflooding could be a viable recovery process for the reservoir. As a result of these studies, a staged development approach was incorporated to test the viability of pattern steamflooding the Eocene reservoir. The objective was to assess key technical challenges associated with steamflooding an anhydrite and gypsum rich carbonate reservoir. Additional challenges were the lack of fresh water available for steam generation, high concentrations of hydrogen sulfide gas, and higher reservoir pressures compared to most active steamfloods. The staged approach called for a single pattern steamflood test followed by a larger multi-pattern pilot. As a result of this strategy, a single pattern steamflood test was implemented in 2006. The design and initial performance of the small scale test (SST) single pattern steamflood pilot in the Wafra 1st Eocene reservoir are described in this paper. The pilot is comprised of one, 1.25 acre inverted five-spot pattern, consisting of four producing wells, a single injector and a single observation well. Continuous steam injection began in February 2006 at a rate of approximately 500 barrels per day cold water equivalent, 600 psig and a temperature of 489 ºF. The primary goals of the single pattern test were to test application of a mechanical seeded slurry evaporator to process produced water for steam generation and to assess steam injectivity into dolomite reservoirs containing gypsum and/or anhydrite. Injectivity assessment included evaluating reservoir response to steamflooding and investigating the variation over time due to rock/fluid interactions. Secondary objectives included analyzing well productivity and evaluating well testing equipment, facilities, and well construction. The SST has a comprehensive data collection and surveillance plan to support evaluation of these goals and objectives. The surveillance plan includes the collection of pre-flood and post-flood core data, frequent well testing for rates and fluid compositions, daily temperature recordings and periodic logging. After two years of operation, primary goals have been tested and exceeded expectations. A continuous thermal zone was developed in the 1st Eocene reservoir and steam breakthrough occurred at several of the producers. Generator feed quality water was produced at maximum throughput rate of 1,200 bwpd via mechanical seeded slurry evaporator equipment. Secondary objectives are currently being assessed with focus on current challenges of corrosion and scaling of producing wells.

Probabilistic Forecasting and Model Validation for the First-Eocene Large-Scale Pilot Steamflood, Partitioned Zone, Saudi Arabia and Kuwait

“…The screening studies were confirmed by dynamic modeling and economic analyses, which led to the decision for a steamflood pilot (Barge et al 2009). The initial pilot small scale test (SST) consisted of a single 1.25-acre inverted five spot with central injector and one temperature observation well (TOW).…”

“…3. Steam injection at the SST began in 2006 and currently continues primarily to evaluate scale-and corrosionmitigation options (Barge et al 2009). Steam injection into the LSP C-Zone, which is the focus of this paper, began in 2009.…”

Enhanced Oil Recovery: An Update Review

“… Cyclic steam injection pilot in Issaran heavy oil field, Egypt [183].  Steamflood pilot at the giant Wafra Field, Kuwait-Saudi Arabia [184,185].…”

Data Analytics Techniques for Performance Prediction of Steamflooding in Naturally Fractured Carbonate Reservoirs

“…The pilot operations are tried in France, Italy, Congo, Turkey, USA, Kuwait, and Saudi Arabia [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43]. The first part of the data collected and used in this study is from field pilots of steamflooding in VO NFCRs reported in the literature.…”