Waterflooding is the method where water is injected into an oil reservoir to increase pressure and stimulate production. This supports pressure of the reservoir and pushes the oil towards a well. Normally only 30% of the oil in a reservoir can be extracted, but this increases and maintains the production rate of a reservoir over a longer period.
Waterflooding was begun as a solution to decreased land elevations. As early as the 1940s subsidence in the Long Beach/Signal Hill area was causing walls and foundations of buildings to crack and breakage of sewers and underground pipes. Remedial actions including trucking in landfill, raising foundations and construction dikes. Studies conducted linked oil production with the cause of sinking land, citing geologic characteristics of the oil field reservoirs. The area affected was approximately 21,600 acres.
In 1955, Charles S. Jones, Richfield’s president, proposed a waterflood solution. Water injected under pressure would push oil ahead of it to the areas of low pressure where the oil could escape through wells. In the following years, six fault block unitization areas were formed and by the mid 1960s the result was a halt of subsidence and increase in oil production.