Carbonated Waterflood Results--Texas And Oklahoma
Authors: Christensen R.J. 
Published: December 2007

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Abstract
Increased total oil production, increased injectivity and significant economic benefits have been achieved from secondary recovery by carbonated water flooding in Oklahoma and Texas projects.
Development of the Orco process method of carbonated water flooding resulted from research with carbon dioxide (CO2) conducted while searching for a raw material which would be suitable as a reservoir surfactant, yet cheap enough to use in quantity.
The process is applied in four steps:small LPG slug,carbonated water containing a small amount of surfactant,carbonated water, andplain water, thereafter.
Skin effect and slime-forming bacteria problems have been corrected with carbonated-water treatments to increase injectivity.
Carbonated-water injection has been completed at some of the Oklahoma projects. Total oil recovery already has exceeded estimates made for conventional water flooding. And these projects will continue to produce for several years. Injectivity increases are pronounced.
Conventional flooding and gas repressuring had failed in secondary- recovery attempts at a Pecos County, Tex., project because of restricting formation clays and sand characteristics. When carbonated water flooding was started, injectivity increased substantially within a short time. Production is increasing and no unusual problems have been encountered.

Introduction
The carbonated-water flooding process is an improved method of secondary recovery. By treating a crude-oil reservoir with controlled amounts and concentrations or solutions of CO2, two advantages appear:increased total oil recovery, andincreased water injectivity.
These two benefits combine to improve economic efficiency.
Oil Recovery Corp. developed the Orco process method of carbonated-water flooding, known as "Orcoflooding", and provides technical assistance when desired for field application.
Six carbonated waterfloods are in operation - four in Oklahoma, one in Kansas, and one in Texas. Two more projects in Oklahoma and three in Kansas are now being developed, with injection to start this spring and summer. Several additional projects are scheduled to start later in 1961.
A resume of the history and development of the process is presented plus descriptions of some of the methods and techniques used in application. Results from projects located in Oklahoma and Texas also are included.