Improved Waste Injection Monitoring and Modified Operational Procedures: The Keys to Prolong Well Storage Capacity

Abstract

Waste generated during exploration, development, and production of oil and gas fields are required to be disposed in a responsible and environmentally friendly manner. Over the years, environmental regulations governing the disposal of such waste have tightened and each day regulatory agencies are demanding more stringent policies, especially for remote and environmentally sensitive areas. Waste Injection (WI) has been proven over the past decade to be the safest and most efficient technology for final disposal of waste materials such as produced water, drill cuttings, spent drilling and completion fluids, scale waste, NORM, produced sand, production and well cleanup waste. This cost-effective technology complies with the strict environmental guidelines, such as the ones governing zero-discharge environments. More regulatory agencies are gradually recognizing WI as a robust solution to safe and assured final disposal of waste generated in upstream and downstream sectors of the oil industry.WI has evolved from a simple pumping operation, with lack of sub-surface understanding, to an assured process that has integrated the knowledge from all areas of the operation: engineering design, equipment and operational parameters, monitoring, and quality control-quality assurance. This continuous assessment guarantees a cyclic process that identifies potential risks at early stages, and allows proper management and mitigation to prolong the life and integrity of the operation. This paper presents the unique and technically challenging injection monitoring and pressure interpretation experience attained in different WI projects worldwide, where the in-depth interpretation of fracture behavior helped as a risk-prevention tool with mitigation options applied to operational parameter well specifics.The continuous monitoring of injection data and parameters assists in developing a well history and a prediction mechanism for well storage capacity, extending the life of the injector and maximizing efficiency for the development of the field.

Deep Underground Injection of Waste from Drilling Activities—An Overview

“…Besides all that was mentioned above, subsurface injections of drilling waste makes the continuous use of oil-based mud during drilling troubled shale formations in environmentally sensitive areas possible [25]. Deep underground waste injections (cutting reinjection (CRI) or downhole waste injection (DWI)) are still the most economic methods for the disposal of waste generated through exploration and production activities in comparison with other available waste disposal methods [26,27]. For example, in the period of two years (concluded by March 2000), in Port Fourchon (Louisiana), more than 160,000 m 3 of waste produced by drilling and production activities containing naturally occurring radioactive materials (NORM) has been injected into a single well with an average cost of $119.5 per cubic meter of waste material, which is far less in comparison with the off-site waste disposal, with an estimated cost of $629 per cubic meter of the same waste material [18].…”

“…No matter which of the above theories is correct, waste slurry injection inevitably leads to changes in local in-situ stress, regardless of the formation that has been selected for injection. Injected waste changes the local stress through three basic mechanisms [27,32,33]:…”