Design Considerations For The Production Operation Of An Alkaline Flood
Authors: Wheeler D.W. , Weinbrandt R.M. , Duncan J.T. 
Published: December 2007

Aminoil USA is conducting a pilot test of an alkaline flooding process in the Lower Main Zone of the Huntington Beach Field. The area where the alkaline flood is being pilot tested was originally drilled in 1940 pilot tested was originally drilled in 1940 and produced by primary means until 1969, at which time a pilot waterflood was initiated in Fault Block 22 using a single normal five-spot pattern. Approximately two pore volumes of water have been injected into the 17,000 ac. ft. project area and it is currently producing at a water-oil ratio of over 20. The same fault block and pattern where the waterflood was pilot tested is being used for the alkaline flood pilot program. program. This paper discusses the design and application problems encountered in modifying an existing waterflood to an alkaline flood and controlling and monitoring the injection and recovery to maximize recovery efficiency and minimize added expense. The pilot flood is utilizing as many monitoring pilot flood is utilizing as many monitoring techniques as possible to correctly evaluate the project's potential for expansion to the rest of the Lower Main Zone.

The current Status is promising. Over two million barrels of soft water preflush have been injected and all injection wells have excellent profiles. At this point there is no response at the producers, but tracer analysis has been initiated to monitor the flood sweep.

Introduction

The Huntington Beach Field is a major producing field lying on the California producing field lying on the California coastline approximately 20 miles southeast of Los Angeles. Figure 1 shows the location of the Huntington Beach Field in the Los Angeles Basin with the offshore area of the field cross-hatched. In May of 1978 Aminoil USA initiated a pilot test of an alkaline flooding process in the Lower Main Zone. The pilot test is using 10,000 barrels per day of a blended produced and brackish water. The blended water is then being softened for use in the pilot test. The primary considerations evaluated in primary considerations evaluated in selecting the water source to be used for the project were environmental constraints and the project were environmental constraints and the effect of salinity on interfacial tension. After the water sources were screened and a source identified which satisfied both the conditions imposed by the environmental constraints and the effects of salinity on interfacial tension, an extensive review of softening alternatives was performed. The results of the review indicated the most practical approach to be ion-exchange. practical approach to be ion-exchange.

ENVIRONMENTAL CONSTRAINTS

All of the produced water from Aminoil's Huntington Beach Field is currently being reinjected into the Lower Main Zone to meet the water flooding requirements. If the pilot alkaline flood is successful and expansion is considered, disposal alternatives of the produced water will have a bearing on the ability to expand the pilot project. The practical alternatives available for produced water disposal are ocean discharge, conversion of the sea water floods to produced water, or utilization of produced water in the alkaline flood. Although ocean disposal is a possibility, the uncertainty of how the EPA will possibility, the uncertainty of how the EPA will eventually treat ocean disposal of produced waste water from onshore operations essentially rules it out as a practical alternative.