Application of CT-Conveyed Perforating with the Sand Jetting Technology on North Sea Deep Horizontal Tight Gas Producer

Abstract

Tight gas developments in the high cost environment of the North Sea are becoming economical and operators are focusing on the technology required to realise these plays and extend field and facility life. Operating companies are targeting tight gas reservoirs with low to very low permeability with long deviated and horizontal wellbore sections. Close attention to the perforating method is required in order to optimise hydraulic fracturing operations whilst minimising rig time. Sand jetting technology has been in use by various industries for many years. Although theoretical papers for oilfield applications were published as early as the 1960s (Brown et al, 1960), it was only after advances in steel metallurgy in the last decade that tools could be made robust enough for real-world oilfield use. In addition, simulation software has improved greatly in recent years, yielding better predictability for this type of operation. This paper will describe coiled tubing-conveyed sand jetting perforating operations for a five stage multi-frac horizontal gas well in the Southern North Sea. The goal of the operation was to create perforations with minimal entrance friction, reduced tortuosity during treatment, and minimise the chance of multiple fractures. Such a treatment would reduce the chances of premature screen-out and the associated costly rig time as well as allow for optimised placement of the proppant following a tip screen out (TSO) design. The challenges associated with performing the operation on a small, unmanned satellite platform will be described, along with pre-job planning and operational steps taken to ensure the sand jet tool could reach the target depths in the deviated well.