Drilling waste disposal using hydraulic fracturing is often the preferred waste management option because it can achieve true zero discharge without being limited by the drilling location. This is particularly true for drilling operations in remote and challenging areas such as offshore Sakhalin Island as there is no established infrastructure for drilling waste management.

This paper presents a case history of managing uncertainties and risks related to a drill cuttings re-injection (CRI) project offshore Sakhalin Island. Although there are uncertainties and risks with the CRI project in this case, regulatory requirements and the operator’s commitment to zero discharge made it the preferred option for drilling waste management. Complicating the decision was a previous injection well where cuttings settling made it inoperative. Thus, the only option was to inject the oily cuttings into a deviated well intended for future use as a development well, which posed a number of risks related to the proposed CRI operation.

Since this is the only option for drilling waste management and loss of this well would have delayed the drilling program and field development for at least a year, managing the risks and uncertainties related to this CRI project and assurance of a trouble-free CRI operation were critical.

This paper presents monitoring and diagnostic analyses that were used for slurry design and optimization, pumping procedure design and optimization considerations, as well as solids transport modeling and planning length of shut-in intervals between batches. These quality assurance and optimization measures were proven to be effective in managing the risks and uncertainties associated with this critical cuttings injection well off Sakhalin Island. At the time of this writing, more than 100,000 bbl of slurry and fluid had been injected into this well without incident.

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