Predicting The Danger Of Hydrate Formation Using A Modified Dynamic Kick Simulator

Special tools are needed in order to optimize operation and safety procedures when planning deep-water wells. One possible technical problem is the formation of hydrates in the BOP or Kill/Choke line. Hydrates, which are ice type substances consisting of frozen mixtures of water and hydrocarbons, may plug the BOP stack and well circulation path and will be very difficult and time consuming to remove. An advanced dynamic kick simulator, developed at RF-Rogaland Research, has recently been expanded to include the determination of the potential for hydrate formation. Using dynamic temperature simulation, detailed component level PVT computations of the hydrocarbon influx, and an advanced hydrate formation algorithm it is possible to obtain the temperature off-set from hydrate formation throughout the well at any time during a simulated operation. The simulator includes code that takes into account the effect of hydrate inhibitor chemicals such as alcohols and salts. Thus it is possible to make several trial runs with differently inhibited muds to compare the danger of running into hydrates. The paper briefly discusses the physical and chemical models used, and it points out how to circulate in a way to minimize the chance of hydrate formation. Simulating kick with hydrate formation is a novel and significant contribution. This will enable the industry to perform planning and engineering of complicated well control situations. In particular it will allow the planning engineer to evaluate the risk of hydrate formation versus the cost of mud inhibition - this will be very useful for low mud weight situations where providing hydrate inhibition is very expensive.