Current Steamflood Technology

Abstract

This paper provides an overview of current steam injection technology. Reservoir data and performance are compiled for 13 selected field projects in the U.S., Canada, and Venezuela. Subjects discussed include oil recovery, well completions, operating practices, and special reservoir conditions. Emphasis is on steamflooding, with some data on cyclic steam stimulation. Introduction The purpose of this paper is to help petroleum engineers keep up with emerging steamflood technology, including both reservoir and operating experience. Useful data and references also are provided. provided. Steam injection is the principal enhanced oil-recovery method used today, accounting for 90% of all oil produced by such methods. Prats estimates the total worldwide oil production rate from steam is about 400,000 BOPD (64 000 ml/d oil). The U.S. produces 60% of this total, Venezuela produces produces 60% of this total, Venezuela produces 35%, and Canada produces 3%. Several large projects are in the planning and construction stages projects are in the planning and construction stages for the oil sands of Alberta and the Orinoco oil belt of Venezuela .Steam injection technology has advanced significantly since the status of steam injection was reviewed at a Canadian Inst. of Mining and Metallurgy meeting 6 years ago. The Oil and Gas J.'s annual review for 1978 lists 99 active steam-injection projects for the U.S., 41 for Venezuela, and 14 for Canada . In addition, petroleum engineers have published several technical papers describing field projects and providing greater understanding of how the process can best be applied in the future.The most notable development in steam injection during the past 5 years is the overwhelming shift to steamflooding, with cyclic steam stimulation becoming an important adjunct, rather than a separate oil-recovery process. This is attributed (1) to the relatively low recovery oil recovery attainable by cyclic steam stimulation and (2) to higher oil prices, which have served to make economically attractive the considerably lower oil/steam ratios characteristic of steamfloods. Field Tests Table 1 gives formation characteristics and Table 2 lists test results for 13 selected steam-injection field tests. These tests represent most of the major steam-injection projects, except for those reported earlier in Refs. 5 and 6. Unfortunately, a few large projects are not listed in Table 1 because sufficient data were not available. These include Santa Fe Energy Co. Chanslor Div.'s 23,000-BOPD (3700-m3/d oil) Midway-Sunset project, Texaco Inc.'s 35,000-BOPD (5600-m3/d oil) San Ardo project, and several steamfloods in Venezuela. Test 4 (Charco Redondo) is cited in Table 1 primarily because of its unique features. This project was a highly instrumented steam pilot in a thin, waterflooded reservoir. Following the steamflood, the field was flooded successfully by in-situ combustion. Tests 6 and 13 are large, cyclic steam-stimulation projects, and the rest are steamfloods. JPT P. 1332