Maintaining High-Performance Injectivity in Water Disposal Wells: An Aradel Holdings Case Study

Abstract

Production of hydrocarbons in reservoirs is normally followed by production of water and sand that is very problematic when it comes to handling and disposal of water particularly in the mature oil wells. Produced water contains residual oil, suspended solids and other related chemicals of the treatment which could lead to the diminishing permeability around the well-bore and thus, lead to the loss of injectivity in water disposal wells. A high injectivity over a long duration is a great challenge of operations especially in the Niger Delta where the nature of the reservoirs is subject to change because of circumstances during operations and the environmental regulations are stricter. This paper defines issues of operations, effective and ineffective solutions and effective results of a manufactured water disposal well in Aradel Holdings Ogbele plant. The article demonstrates that the water disposal well has ensured a high injectivity and throughput during more than ten and a half years despite tubing blockage or loss of injectivity. The paper also brings into focus the treatment strategy employed to prevent the tubing blockage, injectivity loss which assists in having a stable performance of the water well. The plan is permanence of the plant and engineering design, efficient implementation of the project and optimisation of operations over time. The paper also examines the system of produced water plant which can guarantee that enough oil, solids and other contaminants are removed before disposal. Production chemistry is also helpful in the optimization of the produced water with the use of treatment chemicals that consist of water clarifier, scale inhibitor, corrosion inhibitor and biocide that is backed by laboratory bottle tests and field trials. The injection points and rates of chemical are controlled in order to prevent incompatibility and provide effective treatments. Routine sampling, analysis, and monitoring is done routinely through the treatment and injection system and continuous monitoring of the reservoir carries out to ensure that the disposal well is running within acceptable limits. They find that long term injectivity, efficient disposal capacity, can be achieved with water treatment, better chemical control, and integrated well and reservoir monitoring, which is an environmentally friendly and economical way of disposing of produced water in operations of an established oil field.