Review of California Waterflooding Operations

Abstract

Abstract This paper presents a statistical review of California waterflooding operations. Water flooding was first started in California in 1944; and, as of June 1, 1960, there were 55 active secondary recovery water-injection projects. In addition, there are 14 projects in which pressure is being maintained by water injection and 18 waste-water-disposal projects. The number of floods has increased markedly since 1951 when the crude-oil demand began exceeding the supply. However, for varying reasons, 24 water-injection programs have been discontinued. The majority of floods were started following careful preliminary engineering analyses. No serious difficulties appear to have been encountered as a result of either the relatively high oil viscosity or the rather large average zonal thickness. No data are available to evaluate increased oil recoveries which may result from the water injection, but response has been described as "good" in 20 of the 55 secondary water floods. Scope of Investigation The present investigation is concerned primarily with secondary recovery operations, or those water-injection projects which were instigated at a time when reservoir pressures had declined to values substantially less than the original. Other water-injection projects, those undertaken with the intent of maintaining reservoir pressure relatively near to the original or those primarily instigated for the purpose of waste-water disposal, have not been considered in detail. Projects in these latter classifications are listed in Tables 1 and 2. Current California Secondary Recovery Projects As of June 1, 1960, there were 55 active secondary recovery projects in California. At that time, the secondary recovery projects encompassed a total of 322 injection wells, into which water currently is being injected at a rate of 497,895 B/D. Fig. 1 shows the number of active secondary recovery projects in the state by years since the inception of flooding in 1944. This same graph also shows California's total annual crude-oil production and the annual refinery utilization of crude oil. It is interesting to note the accelerated rate at which new projects were started after the crude-oil demand began to exceed the supply. Tables 4a and 4b summarize all available data pertaining to current, active, secondary recovery projects in California.