Oriented Perforation using Tubing Conveyed Perforating TCP Gun with Dynamic Underbalance DUB as Sand Control Method in Low Angle Wells, Offshore Sarawak, Malaysia.

Abstract

The use of oriented perforation as a means of sand control technique has been adopted by many operators in industry. Two low angle wells completed in D field offshore Sarawak, Malaysia with moderate to weak rock strength quality required this method not only to limit the sand production but also to sustain the minimum production of 2500bopd each. Based on onset sand production analysis, reservoir M is predicted to have sand production in the direction of a maximum stress of 135degrees from true north. The wells then are suggested to be shot 0-180degree parallel to maximum stress and it saved the expense of no installation of downhole sand exclusion. This paper outlines the perforation analysis conducted to design the optimum perforation using Tubing Conveyed Perforating (TCP) Gun with Dynamic Underbalance (DUB) that effectively clean the newly created perforations. The operational approach applied to overcome the challenge of achieving desired orientation in almost vertical deviation wells by positioning electronic gyroscope siting on Universal Bottom Hole Orientation (UBHO) sub is also discussed in this paper. The available centralization solutions in market are limited to 30° degrees well inclination with 5°accuracies at three times more cost than conventional TCP. The proposal of oriented perforation at both slanted wells significantly saved lot of project economic and proved as effective sand control method, so far the production target is achieved and maintained with no record of sand production at field. Two newly drilled and completed wells located in offshore Sarawak, Malaysia required oriented perforation with dynamic underbalance using Tubing Conveyed Perforating (TCP) guns. The reservoir quality was weak to moderate rock strength with expected sand production in the direction of a maximum stress (135 degrees from true north) within the nearly vertical wellbore. To limit the sand production, the requirement was to shoot 0-180 degree guns parallel to maximum stress, to save the expense of any sand exclusion method. Another requirement was to use Dynamic Underbalance (DUB) to properly clean perforations, reduce skin, and maximize production. The objective was to achieve a minimum production of 2500 BPD. From Geo-mechanic study, in deviated well, the orientation of perforation is aligned with the trend of maximum horizontal stress. Based on breakout analysis, Shmax direction is 135° from the North. The expected production rate can be achieved with Oriented Perforation even at 0 deg phasing and PI reduced from 55 STB/day/psi to 38 STB/day/psi based on Figure 1 below. The studies conducted on Field D available data concluded that sanding risk is very low with Cased & Oriented Perforation strategy.