Slimhole Wells at the Raageshwari Deep Gas Field

Abstract

During exploration activities in the Thar Desert of Rajasthan, India, Cairn India Ltd. discovered numerous oil fields in the Barmer Basin. The oil reservoirs are relatively shallow and benign in terms of pressure, temperature and corrosivity, but they posed significant flow assurance challenges due to relatively high crude viscosity, wax content and pour point. As a result, surface facilities are reliant on heat for flow assurance. Total reliability of power and fuel supply for the facilities was essential to ensure export product quality and for flow assurance for the waxy oil. The paper presents Cairn’s approach of utilizing state-of-the-art technology that integrates all relevant data scenarios for the drilling and production systems for this lean gas condensate reservoir. This development will provide the necessary power and heating fuel supply and the primary gas supply for the main oil processing terminals and for power generation stations along a 600km heated export pipeline.through the end-of-life for the major oilfields discovered in Western Rajasthan, India. Raageshwari Deep wells target tight, predominantly volcanic reservoirs with cost-effective monobore designs that include multiple fracture stimulations in various pay zones to maximize well productivity. The slimhole well design, dynamic completion design, and careful bit design and selection successfully enabled the drilling of these wells with 26% cost savings on the total budget for drilling ten wells ($ 2M per well). A program highlight was the drilling of volcanic tuff formations in a single run. The paper will describe detail aspects of monobore well planning and well design implementation including fracture stimulations. It will also demonstrate how this significantly improved the well delivery that contributed to effective development plans for these major oilfields.