Research On Snubbing Service For High Pressure Injection Well

Snubbing service means doing work-over jobs such as tubing strings pulling out or running into hole, casing repair and well stimulations by characterized equipments under the condition of keeping pressure, oil and gas in the well. It can efficiently prevent the pollution of well killing to formations, simplify the operation procedures, enhance the production efficiency, and reduce working cost.This paper mainly means to resolve the technical problems of rubber seal and tubing pressure control of snubbing equipments under high pressure. The matching plan for high pressure injection wells has been brought forward to change the primary ringlike seal mode. Utilizing slipper sealed ram preventer, collar sniffer pressure balance pup joints and pressure balance controlling valve system, the working pressure has been raised to 21Mpa from 14Mpa. For the safety of snubbing service operation, in order to increase the view angle of operators, the paper elaborates the structure and principles of visual operating equipments. Aimed at the pipe string structure features of injecting wells, different types of blanking plugs have been worked out, as well as different plug technologies, which result in efficient tubing pressure control in the situation that Diameter Nominal could not satisfy the request of tubing string plug for the reasons such as tubing crustation and so on, or under the conditions of open pipe strings or something like that. By mechanics analysis, this paper has theoretically put forward the safety operation requirements of snubbing service for high pressure injection wells, and met the operation need.