Performance of casing connection for horizontal oil wells

There is a tendency to complicate drilling techniques in the Russian Federation and in the world. It is caused by increase the number of horizontal wells and increase the length of the laterals. Casing with thread connections while run in hole operation in deviated and horizontal wells are subjected to combined loads caused by axial load, bending load, differential pressure. The most critical point of casing string is the thread connection. 50%-80% compression efficiency of connection becomes insufficient. This article describes results of FEA (finite element analysis) for API Buttress and TMK UP CWB connections and full scale test for TMK UP CWB 177.8 х 9.19 N80.