Alkaline Flood Prediction Studies, Ranger VII Pilot, Wilmington Field, California

Abstract

Summary This paper discusses the design of a simulator to model alkaline displacement mechanisms, along with the current understanding of in-situ caustic consumption. Assimilation of laboratory coreflood and rock consumption data, and their use in one- and two-dimensional (1D and 2D) limited-area simulations and in three-dimensional (3D) model of the entire pilot project are given. pilot project are given. This paper also reports simulation studies of alkaline flood behavior in a small 2D area of a field for various concentrations, slug sizes, long-term consumption functions, and two relative-permeability adjustment mechanisms. The scale-up of 2D simulation results and their use in a 271-acre [1096.7-ha], seven-layered, 3D model of the pilot are also discussed and 3D simulator results are compared with initial field alkaline flood performance. Finally, recommended additional applications of the simulator methods developed in this pilot and in other alkaline floods are discussed. Introduction Wilmington is one of the major fields in the U.S. and is typical of many of the Pliocene-Miocene reservoirs in the Los Angeles basin. These reservoirs, which are stratified and are often silty, have low oil gravities and high viscosities. Because of the unfavorable water/oil mobility ratio and stratification, waterflood recovery efficiencies have been low. Tests of Long Beach Unit Wilmington crude, including that from the Ranger zone, indicated that it possibly was amenable to recovery enhancement by alkaline flooding. The concept of activating the natural surfactants present in suitable crude oils by reaction with alkaline water has been noted to have EOR potential because of the low cost of the alkaline materials. Alkaline laboratory flood tests of Long Beach Unit Ranger crude in Berea cores were favorable. In 1976, the City of Long Beach (Unit Operator of the Long Beach Unit) and the U.S. DOE entered into a cost- and incremental-income-sharing contract for a large-scale alkaline pilot in the Ranger zone of Fault Block VII. The pilot and pertinent preliminary studies have been described in four annual DOE reports and a recent paper on the pilot. The pilot's configuration and properties are given in Figs. 1 and 2 and Tables 1 and 2. Preflushing with softened fresh water containing 1.0 wt% salt (NACl) began in early 1979. Alkaline injection with softened fresh water containing 0.4 wt% sodium orthosilicate and 0.75 wt% salt began in March 1980 and continued until Dec. 1983. Part of the plan for the pilot involved reservoir simulation studies to predict performance of the area under continued waterflooding and that anticipated under alkaline injection. These studies are the subjects of this paper.

A Critical Review of Alkaline Flooding: Mechanism, Hybrid Flooding Methods, Laboratory Work, Pilot Projects, and Field Applications

“…As a result of this flooding, the water production for these wells dropped to an average rate of 6000 bbl/day. Table 4 shows Wilmington field formation and fluid properties [31,56,65]. The Shengli oil field is in China and considered to be one of the oldest and largest fields in China.…”

Design and Optimization of Alkaline Flooding Formulations

“…An alkaline flooding project, which encountered severe problems with alkali consumption and scaling, was previously conducted in the Ranger Zone of the field. [19][20][21] Reservoir parameters shown in Table 4 were taken from publications by the City of Long Beach and Thums Long Beach Company . 19 The crude oil, furnished by Thums Long Beach Company, from Well A-52 and brine were analyzed after delivery to NIPER.…”