Applying a Reservoir Simulation Model to Drill a Horizontal Well in a Post-Steamflood Reservoir, Wilmington Field, California

Abstract

Abstract This paper is a case study on the use of a simulation based reservoir evaluation method that led to the drilling of a new well in a seemingly semi depleted steam flooded part of a Fault Block in the Wilmington Field, California. Observations made on this well led to the initiation of a very progressive re-development plan for the area. Information generated from the study should be of significant help for re-development of countless similar field operations that have undergone prior thermal flooding. The City of Long Beach (City) and Tidelands Oil Production Company (Tidelands) drilled and completed a post-steamflood horizontal producing well, UP-957, into the D1 sands of the Fault Block II-A Tar Zone (Tar II-A) in the Wilmington Field, California in March 2004. The well was directionally drilled along the top and most updip structural position of the D1 Sands. The well penetrated the oil-depleted steam chest interval in the main steamflood area and was completed in a relatively immature steamflood area into the highest remaining oil saturated sands in the Tar II-A. The completion interval was selected based on a 3-D deterministic reservoir simulation model with thermal capabilities developed as part of a United States Department of Energy Class III Reservoir project. Prior to this operation, the developed model was successfully used to convert the Tar II-A steamflood operation to a post-steamflood operation. The model employed a flank cold-water injection strategy between two faults to increase and maintain reservoir pressures to prevent steam chest collapse and surface subsidence1. Well UP-957 produced at a peak initial oil rate of 249 BOPD and 723 barrels of gross fluid at a wellhead temperature of 197°F and a pumping fluid level of 2122 ft over the mid-perforation depth of 2403 ft VSS (vertical subsea depth), confirming the potential shown by the model. Since the initial response, the oil rate has declined to 130 BOPD and 1991 BGFPD after nine months of production.