Stabilization of Waste Water Injectivity by Optimization of Chemical Treatment And Mechanical Handling Methods
Authors: Wheeler D.W. 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.
This paper was prepared for the Improved Oil Recovery Symposium of the Society of Petroleum Engineers of AIME, to be held in Tulsa, Okla., March 22–24, 1976. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and with the paper, may be considered for publication in one of the two SPE magazines.

Abstract
Many different approaches have been used in an effort to minimize water injectivity impairment within an acceptable cost range. Certainly the selection of criteria to use as a yardstick when evaluating performance will have a significant impact on performance will have a significant impact on the useful nature and validity of the results.
Burmah Oil and Gas Company has been reinjecting produced waste water into the Lower Main Zone reservoir at Huntington Beach, California, during the past three years. A discussion of the problems which have had a direct affect on injectivity impairment is presented, along with the chemical and presented, along with the chemical and mechanical approaches which have been implemented to solve these problems. In conclusion, well and water quality data are analyzed which, hopefully, give a fair representation of the performance. performance. Pilot waterflooding and the first full scale flood expansion were initiated using sea water from a shallow aquifer. Also, injection into the wells was down both tubing and casing-tubing annulus, neither of which were internally coated. Subsequent environmental considerations and the Ocean Discharge Plan of 1972 resulted in the decision to Plan of 1972 resulted in the decision to reinject produced water into the Lower Main Zone.

Discussion
Prior to the initiation of waste water re-injection into the Lower Main Zone, an extensive review was conducted to establish parameters which would have an affect on parameters which would have an affect on injectivity impairment. Limits were established for suspended solids, oil, and dissolved hydrogen sulfide. It was felt that if the limits were exceeded, injectivity impairment would result. Using these parameters, facilities were designed to effect the parameters, facilities were designed to effect the desired removal efficiencies.
The designed and subsequently installed treatment facilities are described below:
Water from free water knockouts is processed through skim tanks, retention tanks, processed through skim tanks, retention tanks, flotation cells, and a filter plant prior to reinjection. A diagram of the facilities is presented in Figure 1. The only significant variation compared to other similar operations in the Los Angeles Basin is the removal of dissolved hydrogen sulfide prior to reinjection.
Biologically induced corrosion problems observed during the pilot flood were more difficult to control as a result of ferrous sulfide accumulations throughout the injection system, although the sea water was dissolved-hydrogen-sulfide-free.