Abstract
A new dual-lateral subsea well in the Aasgard Field (Haaland et al 1996) was recently completed with Multilateral Drilling Stimulation Technology (MDST) in one of the lateral legs. MDST was developed in a Joint Industry Project (JIP) with Fishbones AS, Statoil Petroleum AS, Eni Norge AS, Lundin Norway AS and Innovation Norway. The project was also supported by the Research Council of Norway. The technology stimulates wells by creating a large number of laterals from the wellbore into the formation. The laterals are drilled utilizing small diameter tubes with drill bits and turbines which are conveyed into the well as integral parts of an open hole liner. For the laterals' drilling process, drilling fluid is circulated for a few hours using the rig pumps. This circulation turns the turbines which drives the bits into the formation creating the laterals. MDST was qualified to Technology Readiness Level 4 (TRL4), Qualified for First Use, as part of the JIP. A total of 144 laterals were drilled from the mainbore to increase productivity from the tight sandstone formation. The target reservoir, named Upper Garn, is comprised of an undeveloped oil bearing tight sandstone with intermittent cemented stringers overlaying a developed gas formation. MDST was selected as the stimulation method with an objective to increase productivity without the risk for connecting the well with the gas formation. For the drilling and completion operations, a semi-submersible rig was used. The production results indicate that MDST increased productivity in this application.
