簡介：最近，英國工程設(shè)計公司AnTech宣布，它升級了其井口出口，以在高溫高壓油井操作更具安全性。
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UK engineering design firm AnTech Limited recently announced the reengineering of its Wellhead Outlet to operate more safely in the higher temperatures typically encountered in high pressure/high temperature (HP/HT) wells.
The Wellhead Outlet is a device that connects downhole cable to the surface telemetry system for permanent completions in which pressure and temperature must be continuously monitored. The downhole cable terminates in a pressure bulkhead and then connects to the surface cable, a design which ensures that in the event that the downhole cable is flooded, the integrity of the wellhead is maintained.
The outlet was introduced in 2000 and was ATEX-certified for use in Zone 1 and 2 hazardous areas (those areas in which the presence of vapors or mist may pose an ignition risk). The outlet redesign was done in response to customer demand for an ATEX-certified tool that could be confidently used in hotter wells, according to AnTech. “We realized that we had to alter it in such a way that it would adhere to the ever-increasing safety regulations being adopted to protect those working with HP/HT wells,” said Toni Miszewski, Managing Director of AnTech.
The outlet originally was rated at a maximum ambient temperature of 40°C, which specified the maximum allowable temperature around the component (not the air temperature) with a maximum current of 26 amps running through it. With these specifications, the company was able to designate the outlet with a safety rating of T6, which per ATEX specifications means that the temperature of the outlet would never rise above 85°C, even if it is operating at maximum ambient temperature and current levels.
While this rating was acceptable for situations in which the outlet was operating on relatively low temperature producing wells and reservoirs, it was inadequate for hotter well environments. To create an outlet that would function effectively in these situations, AnTech embarked on a program to address two primary issues:
Educating customers on the difference between ambient temperature and air temperature. The definition of ambient temperature factors in the hotter wellhead temperature, while air temperature does not.
Raising the ambient temperature rating of the Wellhead Outlet to allow operators to meet the safety regulations imposed by higher ambient temperatures in hotter well regions.
AnTech engineers reviewed the current requirements for the range of applications in which the outlet was to be used, and found that the 26-amp current rating was higher than necessary. Therefore, they reduced the current rating to 3 amps, which did not impact the device’s operation and allowed for a nominal increase in operating temperature.
Engineers next reviewed the temperatures typically exhibited in hot wells, and found that the standard safety rating at 85°C was not realistically achievable, since the ambient temperature of most hot wells could often be higher than this. Following a thorough testing program, AnTech’s engineers deemed that the safety rating of the outlet could be lowered to T5 (100°C) without any impact on safety or performance, meaning that the outlet could be used in hotter wells and under a broader range of applications.
These changes have resulted in the Wellhead Outlet being rated to between -20°C and 90°C ambient temperature, a significant increase over the original ambient temperature operating envelope of -20°C to 40°C.
AnTech is planning a further increase in the operating range for its Wellhead Outlets, and in Q1 2009 the company will apply for ATEX certification for an outlet that can perform safely at a maximum operating temperature of 125°C.
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