The buttress thread form, also known as the breech-lock thread form, refers to two different thread profiles. One is a type of leadscrew and the other is a type of hydraulic sealing thread form. The leadscrew type is often used in machinery and the sealing type is often used in oil fields.
1. Connections must be clean and dry when applyingthread lock.2. Apply a thin coating of thread lock on 50% of thepin threads furthest from the pipe body.3. Do not apply thread compound to pin or box.Make Up1. API Buttress connection is designed to be made upto a final position, there is no final torque specified.2. Make up acceptance criteria is defined based on therelative position of the coupling face compared to thetriangle stamped on the pin end:.Minimum Make up: One full thread turn beforetriangle base..Maximum Make up: Triangle apex.
3. There is no torque specification for API Buttresshowever torque values required to reach an acceptablemake up tend to be similar within the same batch of pipe.4. In order to determine make up torque for the stringto be run:.Make up the first 15 joints to the base of the stampedtriangle, taking note of the required torque for each joint..Calculate the average torque..Use the average torque to make up the string..Ensure all make ups are acceptable by checking thecoupling face position within the triangle.5. It may occur that during the make up, the couplingrotates on the mill end. This can be allowed providedthe coupling face on the mill end does not exceed theapex of the triangle stamped on the mill end pin.
Running1. To avoid cross threading stab pipe in a smoothcontrolled fashion ensuring the pipe is vertical whendoing so, continue to support and stabilise the pipethroughout the stabbing and make up operation.2. Upon commencement of initial rotation use lowRPM (5 RPM or below) in order to ensure the pipe hasnot cross threaded during stabbing.3. If cross threading is evident, immediately reverserotate the pipe slowly, break out and inspect bothconnections.4. Maximum spin in speed should not exceed 15 RPM.
Pulling1. Automatic stabbing system or stabber is highlyrecommended to maintain the pipe in a verticalposition.2. Apply the back up tong jaw on the lower part, overmill end, of the coupling.3. Apply power tong in low RPM (3-5 RPM) to breakout the connection, ensuring the pipe is stabilisedduring the break and spin out process.4. Visual inspection is recommended to classify thethread condition. Any rejected connections should beclearly marked and segregated for further investigation.5. Apply clean, dry thread protectors after applyingstorage compound on clean, dry connections.6. Storage / thread compound should always beapplied to connections post job, even rejects.
AddressNorth Shepherd Dr #100, Houston, TX 77007
North Shepherd Dr #100, Houston, TX 77007
Phone: +1 (281)826-1860
Fax: +1 (832)747-3476