Title: Injection Well Stimulation: Putting Away More for Less in California Waterfloods
Abstract: Abstract The waterflood is the most widely used and most successful secondary recovery technique in the oil industry. The injection of produced or make-up water into an oil reservoir can increase recoveries from an average of 19% of original oil in place to as much as 55%1 by driving or sweeping additional oil from the reservoir as the water cycles from injection wells to production wells. The challenge to operators of water flood fields is to maximize their water injection rates at as low a cost as possible since injection wells themselves are not revenue-generating assets. Just as production wells periodically require stimulation to improve productivity, the injection well also develops near-wellbore skin damage that reduces injectivity over time. Injection water quality and incompatibilities with native reservoir fluids can lead to scale or other debris blocking pore throats and reducing near-wellbore permeability – thus requiring stimulation. A large percentage of California injection wells are completed across multiple sands. Although fracture stimulation treatments generally result in greater conductivity between the wellbore and the reservoir, acid stimulation remains the technique of choice for restoring the injectivity of the majority of these wells. A fracture treatment would result in communication of these sands behind casing and eliminate the ability of the operator to control which sands are taking injection water. This paper discusses unique acidizing chemistry and placement techniques that have demonstrably improved injectivity while maintaining the integrity of the barriers between sands in a number of waterflood fields in California. Optimization of acid chemistry and placement improves the depth of penetration of the treatment, reduces the risk of near-wellbore formation deconsolidation, extends treatment life, and reduces the overall cost per barrel of water injected.
Publication Year: 2004
Publication Date: 2004-09-26
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 6
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