Circulating Valves
- The valve is configured to be run in hole in the normally open position, other valve configurations are available.
- This will allow the drill string to fill up via the valve ports in a closed system operation.
- The valve operates in response to pressure drop across the piston generated by fluid circulation, such operation may be controlled through variation of the piston nozzle.
- The valve cycles to close will vary, typically this will require eight cycles.
- The valve is controlled through a unique timing mechanism which allows sequence position to be verified on surface prior to running in hole.
- The valve may be utilised in conjunction with whipstock systems, packer setting operations, tool actuation and other down hole applications as required.*extra text below to be included on the website.
- The valve may be utilised with Gyro and MWD systems for flow bypass to annulus for whipstock system, packer or other down hole tool orientation prior to setting or for other operational requirements.
The valve may be utilised to boost annular velocity for hole cleaning, as well as fluid displacement applications in well bore clean out scenarios. McGarian TDC Limited has developed a circulation valve primarily for use with hydraulic set whipstock systems to facilitate survey and orientation when running with MWD systems. The valve is normally open whilst running in hole and so may be used to assist with the fill of the running string, and in the event the whipstock assembly needs to be pulled out of hole unset on a contingency basis, the string is not pulled wet.
The valves are configured with 8 cycles to close, where on the 7th cycle the valve partially restricts flow and gives a surface pressure indication that the next cycle is to close the valve. The valve actions respond to low flow rates which eliminates high pressure surges on the closure cycle.
The circulation valve may be configured to operate on the basis of normally closed with an intermittent open cycle.
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