Abstract

Cuttings re-injection (CRI) technology is a reliable waste management option for eliminating environmental liabilities and reducing surface contamination risks associated with traditional disposal techniques. The technology complies with the strictest regulations enabling oil and gas exploitation in areas where it was not before possible.

Three wells were drilled in the Chambira field (Block 8). Drilled cuttings from those wells were stored in pits for three years due to the lack of a conventional disposal method that meets Peruvian regulations. Two years later in 2013, CRI technology was selected as the waste management option for disposing the cuttings. An old abandoned well, CHAM-124XCD, was conditioned and prepared for re-injection. Cuttings were removed from the pits and transferred to the processing unit where they were mixed with water and additives to form a suitable slurry, which was injected down the hole into an interbedded formation. This first CRI application in Block 8 eliminated the environmental liability of the Chambira field. All drilled cuttings accumulated from previous drilling operations were successfully injected. Approximately 100,000 bbl. of waste (including spacers and displacement fluids) was disposed into the Chambira formation. As a result, three (full-size) cutting pits were cost-effectively cleaned.

This paper shows that the selected cyclic injection technique enabled disposal of all cuttings without disturbing the initial stress state of the formation. After the injection, minimal changes in horizontal stress and fracture propagation pressure were observed; thereby, demonstrating that the injection strategy was appropriate for the formation. The results from this operation indicate that cuttings re-injection technology can be a very effective method for eliminating drilling cuttings in remote and mature fields.

This paper presents a successful CRI application in a remote Peruvian oil field as a reliable and cost-effective solution for cuttings disposal. Properly customizing available equipment at the site enabled complete disposal of the accumulated cuttings, which were major environmental and financial liabilities for the operator. The customization methods developed during the re-injection operation in Chambira field are new and applicable for similar formations in other fields.

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