Design of a capillary clamp for oil and gas installations
Installations of fiber optic sensor systems for oil and gas wells typically involve the insertion of small capillary cable along side larger pressure tubing, often in lengths of a mile or more. While installation rigs have large handling mechanisms to hold the pressure tube as it is installed, they do often do not provide a way to hold the capillary cable that contains the fiber optic line. In order to install the fiber optic capillary with damaging it, it was necessary to provide the install team with a way of supporting the weight of the capillary between moves.
To meet this request, a clamp system was proposed and developed. Finite element analysis (FEA) of a section of the capillary under clamping was conducted. This analysis demonstrated the maximum force that can be placed on the capillary without deforming it, a key constraint of the design. The maximum clamping force on the capillary was compared to the weight of the capillary section suspended below the clamp and found to be capable of supporting the capillary’s weight.
A test article was created to test the design and show it was ready for use. The capillary clamp was able to resist 1500 lbs. of axial force before slipping, well in excess of the 300-500 lb. requirement. The clamp also served to restrain the capillary without deforming it. The clamp design was proven successfully and additional samples were made and put into service.