Record Propped-Fracture Stimulation Performed from a Jackup Rig in the North Sea

Abstract

Abstract Proppant-based hydraulic-fracture stimulation in the southern North Sea is becoming increasingly popular and, in some marginal fields, can be considered crucial to maximize reservoir contact; thus, improving deliverability from tight-gas sandstone formations. Because of the low availability of purpose-built or temporary stimulation-class vessels in the North Sea, an alternative concept to place more than 250,000 lbm of proppant into well 49/17-14 from the Ensco-100 jackup rig was proposed, reviewed, and successfully executed. This paper presents the prejob engineering process and executional summary of the North Sea’s largest rig-based proppant-fracture stimulation, where in excess of 250,000 lbm of resin-coated proppant was placed at fracturing rates of 35 bbl/min, with greater than 7,000 hydraulic horsepower available. Discussed within this paper are prejob planning measures and the logistical challenges overcome during completion of the project. In addition, the paper introduces the first use of a microemulsion surfactant in the North Sea to help optimize cleanup time by reducing in-situ capillary pressure. The overall success of this project proves there is a viable commercial and technical alternative to vessel-based fracture stimulation in the North-Sea market where suitably sized rigs are available.