Performance of Premium Connections depending on Thread Design and Lubricants

The research activities of tubing and casings are influenced by the increasing of the capital investment for the area exploration and production of the oil and gas industry. A casing is a pipe which is cemented into the borehole for stabilizing reasons. For the well completion to contain the production fluids tubings are used. The design specifications for connections are nowadays higher as in the past. The drilling activities for oil and gas are going to extended reach and horizontal wells. This means that the effect of high temperature, high pressure and the downhole forces on casing and tubing increase. The next generation of tubular connections called premium connections must fulfil also a gas tight joint criterion. The design of the threads influences the tightness of the connection but the performance of the joint depends also on the chosen lubricant. The main disciplines of a lubricant are the reduction of friction and galling and the providing of a protection against corrosion. The main focus of this thesis was the evaluation of the thread parameters which influences the design for a gas tight connection. The result of this study shows also how the performance of a connection is affected by the thread design and the chosen lubricant.