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.