Design And Development Of New High-torque Washover Pipe

Oil and natural gas play important roles in China’s energy structure, and development of oil. natural gas.It requires a lot of pipe, due to geological conditions vary widely, however, in the drilling process; There will be all kinds of unexpected breakdowns and accidents. Washover pipe is widely use in processing oil and gas drilling accident and failure in recent years, with the continuous development of the oil and gas fields, oil and gas horizontal well increase widely, when the oil and gas sticking in the downhole, it will applied washover pipe for milling as to solve problems. Washover pipe remove the dropped casing through the threaded connection.However, there is no fixed standard criteria for the washover pipe thread connection from domestic to the foreign countries, the thread connection strength is not very reliable.As the incident handling tools do not form number of production and consumption scale, the manufacturer has not been put into research efforts on quality, standard and thread structure development. There are also some missing and unreasonable items in the oil industry SY standard5487-92"the washover pipe", Firstly, it only recommended thread profile size, lack of thread diameter and length, resulting in it can’t exchange domestic and foreign manufacturers’ thread, there is no common industry thread gauge as well; Secondly, the mechanical properties is too low to use resulting the thread is easy to broken, lead to more dropping accidents in the hole; Thirdly, there is no reasonable tolerances in inside and outside diameter, resulting the inner wall of the outer thread is too thin, there is a certain safety hazards in the down hole.Under this circumstance, it designed several new type thread to test, selecting preferably higher tensional strength thread structure, rectifying the original SY5487-92"the washover pipe" and forming the internal standards. The subject is to solve the thread structure, mechanical properties, dimensional tolerances, standards modify and so on, providing higher torque, greater reliability, and interchangeably accident processing tools for drilling production.