The Coiled Tubing Motorhead Assembly is a downhole tool used in coiled tubing operations to provide well control, manage fluid circulation, and allow safe emergency disconnection of the tool string if needed. It is typically installed above the downhole motor but can also be used independently in other downhole assemblies where its functions are required. The assembly is designed to operate reliably under the high pressures and temperatures commonly encountered in deep oil and gas wells.

The MHA includes dual check flapper valves that prevent well fluids from flowing back into the assembly or the coiled tubing, protecting both the equipment and the wellbore. It also incorporates a hydraulic emergency disconnect (HDI), which allows the coiled tubing and tool string to be safely separated if the tool becomes stuck. The disconnect is activated by dropping a metal ball from the surface into the release seat. When pressure reaches a predetermined level, the pins shear and the assembly separates, allowing safe retrieval of the coiled tubing. In addition, the assembly features a circulation valve that allows fluids to flow through the coiled tubing into the annulus, helping to flush and clean the wellbore. A rupture disc within the circulation valve ensures that circulation can be established even if normal flow is blocked.

The Coiled Tubing Motorhead Assembly is engineered for durability and operational safety. It is compatible with coiled tubing sizes ranging from 42.9 mm to 73.0 mm in maximum outer diameter and 11.1 mm to 17.5 mm in minimum inner diameter. Activation ball sizes for the hydraulic disconnect range from 15.9 mm (0.625") to 22.2 mm (0.875"), while the dual check system uses balls ranging from 12.7 mm (0.500") to 19.1 mm (0.750"). The assembly can be connected using standard threads, including 1.0" AMMT, 1.5" AMMT, and 2-3/8" PAC, ensuring compatibility with a wide range of coiled tubing and downhole tools.

The flow paths in the assembly are designed to allow fluids to move freely while protecting the valves and other components from erosion and damage, ensuring long-term reliability. The combination of check valves, hydraulic disconnect, and circulation valve provides multiple layers of safety and control, reducing the risk of damage to the wellbore or equipment during intervention operations.