This paper discusses the application of fibers for the Frac and Pack application for Brunei Shell Petroleum (BSP). Seven wells with a total of seventeen fracturing treatments in this study are on a multilayered unconsolidated formation, where sand control is a part of well management during the production life of the wells. Previous techniques of open hole external gravel packing and cased hole Internal Gravel Packing (IGP) for controlling formation sand were challenged by reduced flow efficiency of the wells. The recent development of Expandable Sand Screen (ESS) combined with fracturing treatment could not control produced sand, due to failure in perforation techniques. An improved idea of perforating only the lower side of deviated wells using minimum viscosity fluids and minimum amount of pad with limited proppant sand concentration resulted in low net pressure build up.
These challenges were prevailed over by the application of a new fiber technology in which fiber is used (1) to transport higher sand concentration to the fracture, and (2) to control the sand flow back during production as well. Since this technology is physical rather than chemical, the proppant flowback is controlled without specific shut-in time, temperature, or pressure constraints. The use of fiber technique prevents sand falling down from perforations and ensures the ESS running smoothly. This technique enabled Brunei Shell Petroleum to cost effectively complete the highly deviated wells with stimulation and sand control. In presence of the fiber, higher proppant concentrations up to 9 ppa could be used successfully even with linear guar gel. This promotes the net pressure build up which is vital for fracturing treatment in high permeability reservoir. Eleven fracturing treatments on five different wells have been performed with excellent results.
Oil and gas industry in Brunei Darussalam started as early 1930's where wells were mostly explored onshore and shallow marine environment. The fields straddle along the coastline about 120 kilometers from Bandar Seri Begawan to Kuala Belait. Tali Field (Fig. 1) is a small field which is about 10 sq km in size 2 km from the coastline. With unconsolidated and high permeability sand, most of the wells here encounter the danger of formation breakdown and premature sand out, which make sand control a requirement during their production lifetime.
Historically, hydraulic fracturing has been applied to low permeability formations as a means of further stimulation to increase the production rate.1,2 In the recent years, hydraulic fracturing for controlling formation sand and enhanced productivity in high permeability unconsolidated formations has gained broader acceptance.3 Sand control and stimulation methods for wells in multilayered unconsolidated formation, have started as early as 1960's.4 These techniques included stand alone wire-wrapped screen, 5,6 in-situ sand consolidation with chemicals, 7 gravel packing, 8,9 oriented perforating 10 and limited application of frac packing techniques.11
The application of sand control methods in Brunei have shown remarkable changes in terms of technology used to ensure the treatment capable of controlling the formation sand production as well as maintaining the hydrocarbon production rate.12–16 Implemented sand control techniques are such as standalone wire wrapped screen, in-situ sand consolidation with chemicals, conventional gravel pack for cased hole and openhole, and Frac-Packing. The optimization of these completion techniques also has become more important considering the optimum hydrocarbon production with total sand control and operational risk.
The majority of the wells in this study were side tracked from the abandoned wells in Tali field offshore to new targets. With complex geological structure, the wells were drilled at high deviation angle or horizontally to reach to target from existing wells and production platforms.