Drill Cuttings Re-Injection Research Articles

Environmental and living organisms’ disaster caused by discharge of drilling fluid waste

The oil and gas industry plays a vast and vital role in our society. Despite the numerous benefits of the production of crude oil, its activities pose a lot of dangers to the environment and living organisms because it generates a huge volume of solid and liquid wastes, thus, these wastes require treatment before disposal. The major drilling wastes are drilling muds, drilling cuttings, and obnoxious gas emissions. Parameters that should be considered during the disposal of decontaminated drilling muds and drill cuttings are heavy metals. These wastes are introduced into the environment through accidental spills as well as intentional discharge. The discharge into the environment has effects on humans, plants, birds, soil, and also aquatic life. Generally, oil based drilling fluid usage and disposal are not preferable. However, water based drilling fluid and synthetic based drilling fluid can be a technically and economically disposed because they are biodegradable. Generally, drilling waste disposal options are offshore disposal, onshore disposal and drill cuttings re-injection. Zero discharge can achieved by drill cuttings re-injection. However extensive study must be carried before drill cuttings can be re-inject to the formation. Disposal options must be evaluated based on economics, environment and operational aspects. This study aimed at evaluating the heavy metals present in the drilling fluid waste and drilling cuttings. The experiment was achieved with the aid of a Flame Atomic Absorption Spectrophotometer (FAAS). Upon the investigation, it was discovered that lead concentration in drilling cuttings was the highest with the concentration of 1,058.9 mg/l and drilling fluid was 190.3 mg/l whereas NUPRC limit is 5 mg/l; the total chromium concentration in drilling cuttings was 19.16 mg/l and drilling fluid was 8.38 mg/l whereas NUPRC limit is 8 mg/l; zinc was 58.10 mg/l in drilling cuttings while in drilling fluid it was 23.96 mg/l whereas NUPRC limit is 50 mg/l; silver concentration in drilling cuttings was 14.67 mg/l and drilling fluid 0.91 mg/l whereas NUPRC limit is 5 mg/l; Cadmium concentration in drilling cuttings was 2.17 mg/l and drilling fluid was 1.36 mg/l whereas NUPRC limit is 1 mg/l. In no doubt. The study has shown that disposal of this drilling fluid waste and drilling cutting directly into the environment without treatment will be detrimental to the living organisms and therefore should be discouraged.

Investigation of Drill Cuttings Reinjection: Environmental Management in Iranian Ahwaz Oilfield

This study was to assess the feasibility of drill cuttings reinjection (DCRI) by hydraulic fracturing in two typical wellbore configurations: annulus injection and a dedicated disposal well by tubing and packer completion in one of the oil wells in Ahwaz oilfield. This article shows that the Mishan formation is more appropriate for DCRI in the Ahwaz oilfield. The optimum parameters such as injection rate, batch size, and shut-in time were simulated and used to determine the geometry of hydraulic fractures created during injection and to ensure that the fractures are precisely developed within the targeted injection zone.

Increased Assurance of Drill Cuttings Reinjection: Challenges, Recent Advances, and Case Studies

Summary The handling of drill cuttings and other wastes generated by drilling operations is both an environmental and economic issue. With ever-tightening environmental regulations and the green operation initiatives of operators, drill cuttings reinjection (CRI) into subsurface geology is often the preferred option, allowing operators to achieve zero discharge because oily cuttings are returned to their place of origin. When the technology was introduced about a decade ago, injection into a single well had a maximum slurry volume of approximately 30,000 bbl. Now, particularly in very large projects, several million barrels of slurry can be injected into a single well. This represents more than 1,000 times the volume of a typical hydraulic fracturing job, or more than 100 times that of earlier cuttings reinjections. In some cases, the success of the CRI operation is critical, either because there are no backup options or because the economic and environmental impacts are too significant. This paper describes the challenges faced in CRI projects, along with recent advances and experience gained in tackling these challenges through modeling, cuttings slurry and operational procedure design, monitoring, and verification. For example, much progress has been made recently in slurry rheology design and operational procedure selection such as suspension and displacement to avoid loss of injectivity and to maximize disposal capacity and minimize health, safety, and environment (HSE) issues. The authors will also present a risk-based approach that integrates deterministic software and tools, available data, knowledge, and experience, for modeling of geological and operational uncertainties and potential risks to increase quality assurance. Case examples will be presented to illustrate the value of this integrated approach. Best-practice guidelines and recommendations will be provided for data collection, design and engineering, operation, and monitoring.

Drill Cuttings Reinjection

This article is a synopsis of paper SPE 72308, "Design Considerations in Drill Cuttings Reinjection Through Downhole Fracturing," by Ahmed S. Abou-Sayed, SPE, and Quanxin Guo, SPE, Advantek Intl., originally presented at the 2001 IADC/SPE Middle East Drilling Technology, Bahrain, 22-24 October.