Remedial Well Impairment Treatment in Water Disposal Wells: A Field Experience

Abstract Organic and Inorganic Scales, bacteria activity, and waxy agglomerations occurring from Injecting poorly treated produced water into old or depleted perforations can be treated by maintaining the right treatment fluid mix, applied in the right sequence that will allow for easy injection and reduction of high back pressures to surface. This paper discusses the treatment of two wells with perforation blockage and Wellbore impairments from the injection of produced water which led to high surface injection pressures, prevention of perforation penetration, and fluid migration which ultimately led to shutting down a section of the production facility for months. The procedure involved using a Coiled tubing workstring for pre-injection testing of the affected wells to develop pressure baselines, mixing and squeezing a stimulation treatment system into the perforations, and then allowing it to cure, while monitoring the pressure drop-off trend. After curing, a post-injection test was conducted to determine the new well parameters for subsequent injections. The fluid system was designed to treat impairments resulting from organic and inorganic chemical reactions which has caused damage to the perforations and near the wellbore. The selected Well data such as the production profile, and the reservoir information including bottomhole pressure, bottomhole temperature profiles, and perforation intervals were analyzed as various other Well parameters were not known for the candidate wells needed to build a fluid system that could handle the requirements of an unknown causative agent. Laboratory testing was carried out by simulating the reservoir conditions with the proposed fluid recipe against the actual produced water injected into the wells. Post-injection analysis of the Wellhead pressure and surface choke indicated that the deployed fluid system caused a reduction in the Wellhead pressure which will allow the continued produced water injection as desired.