Maximizing Brine Recovery After the Displacement of Reservoir Drill-in Fluids to Reduce Well Cost Via New, Alternate Technology In a Reservoir Offshore Abu Dhabi
Authors: Seales Sheldon Peter Anthony , Alaleeli Ahmed Rashed , Tveteraas Jan Erik , Roberts Daniel Martin , Aasland Glenn , Billomos Patrick Ray 
Published: December 2021

Abstract

Objectives/Scope
This paper outlines a new and innovative technology for brine recovery after the displacement of Reservoir Drill-In Fluid Non-Aqueous Fluid (RDF NAF) to Completion Brine and the associated operational, logistical, environmental and economic benefits associated with it. A unique slop treatment technology has been utilized to recover and reuse more than 2,168 bbl per well of expensive contaminated completion fluid to help manage losses and avoid injecting valuable completion fluid into operator's injection well. This has also resulted in reducing impact to the life of the injection well and burden on formation, thereby minimizing impact to subsurface environment and contributing to lower well cost.

Methods, Procedures, Process
The contaminated brine was transferred from the displacement of RDF NAF to brine and processed using a novel slop treatment technology to reduce the NTU and TSS to completion brine specifications required for completion operations. After displacing the well from RDF NAF to brine, typical contaminants would be RDF NAF and hi-vis spacer (water-based). The oil-contaminated brine was usually transferred to the tanks of the cuttings treatment contractor, treated and injected into the operator's cuttings re-injection (CRI) well. The new procedure isolated the contaminated brine to be processed through the slop treatment technology to separate and remove the oil and solids from the brine. The slop treatment involved passing the contaminated fluid through a decanter, solids particulate filter, three-phase separator and then a polishing filter to process the fluid to the required NTU and TSS specifications.

Results, Observations, Conclusions
The slops treatment unit was implemented for brine processing in 2020 and since then, the solution has achieved desirable operational, logistical, sub-surface environmental and cost related benefits. 2,168 bbl of expensive, contaminated completion brine has been processed per well, for subsequent reuse in the completion operations. Utilization and implementation of this mechanical process, versus the historical filter press process, at the source has had clear tangible savings that can be achieved in all areas of the operation, due to the capability to process oil-contaminated brine at a higher clarity and also the viscous brine at a faster rate. This new processing strategy allowed the operator to set new standards with regards to the recovery of oil-contaminated brine, in the UAE.

Novel/Additive Information
This is the first successful processing of oil-contaminated brine to be completed in the UAE utilizing a mechanical technology. This process has established new baselines for the operator to be able to recover oil-contaminated brine. By adapting the existing site-based slop treatment technology, this solution has bridged a gap in the market by using a novel mechanical process to optimize oil-contaminated brine recovery efficiency and maximize returns for operators.