Use of electrochemical cells to reduce the environmental footprint of Oil wells Plug & Abandonment.

Offentlig prosjektsammendrag

It is projected that Equinor will have to permanently P&A (Plug and Abandon) over 1,200 wells within the next 40 years. The standard for well integrity requires that for permanently abandoning a well, barriers shall extend across the full cross section of the well. The purpose of the cross-sectional plug is to guarantee the isolation of reservoirs and other sources of inflow that could, among others, contaminate water reservoirs or leak hydrocarbons to the surface. To provide full access to the cross section of the well, a window in the present metal tubing has to be cut, milled or in some cases the metal tubing would have to be entirely pulled out of the well. Most of the technology currently available to open this window requires the use of a drilling rig and all the environmental footprint associated with it. It is estimated that the emission related to plugging these wells may exceed 260K Tons of CO2 per year or 10M Tons over the next 40 years. Fortunately, there is considerable industry focus on developing new technology that will enable the many operations involved in P&A to be performed without the use of a rig. Upcoming rig-less P&A technology such as the dSolve project, would complement each other and, together, enable a rig-less P&A operation, substantially reducing the CO2 emissions. The dSolve project is based on a fundamental research performed and published by Equinor and SINTEF. It demonstrated that electrochemical cells could be used to accelerate the corrosion of the casing in order to open cross-sectional windows in tubing, without using a rig or coil tubing. It was also demonstrated that the window could be opened competitively, in a variety of casing string designs while producing environmentally friendly by-products. The objective of this project is to learn how the electrochemical cells operate under downhole conditions and how the by-products from the corrosion process affects the well and the operation.