Evaluation of Orientated Perforating in the Buzzard Field

Abstract

Abstract Orientated perforating is used to orientate the perforation tunnel parallel to the highest in-situ stress plane in order to reduce and/or delay sand failure. The technique is most effective in high angle and horizontal wells, so early Buzzard wells were perforated with conventional 60° phasing. Orientated perforating was subsequently adopted on Buzzard after log derived sand strengths were generally weaker than prognosed. The following paper presents the results of a review of six months sand production data from 21 production wells, in an attempt to correlate sand production with perforation orientation. Due to inherent inaccuracy in allocating sand production to individual wells, wells were categorized as high, medium or low sand producers and various parameters such as hole inclination, azimuth, and UCS rock strength were considered to establish correlations between perforation orientation and sand production, all of which were inconclusive other than a slight correlation showing increasing sand potential with hole inclination. As all wells are sub-horizontal and the sand strength is marginal for a passive sand control techniques, it is concluded that orientated perforation does not give any measurable reduction in sand production from Buzzard wells. The effect of perforation orientation on liner erosion was reviewed using Computational Fluid Dynamic models of a nominal 100ft 5.1/2" liner section. This showed no significant difference between 10–350° and 60° phasing perforation, instead wellbore inclination, flow rate and sand particle size increase the potential erosion rate in some wells.