Wellhead isolation tools (WIT) are used during frac jobs to protect the wellhead from excessive pressure and damage from proppant-chemical-laden fluids. Typically, these tools are installed onto the wellhead by a crane truck built for this purpose. There is usually a hydraulic system on the crane truck to operate the tool and to open and close the master valve on top of the tool. The controls for operating the crane, WIT, and master valve are typically all in the same area so that one operator can control the whole process. However, having all the controls in one place increases the likelihood that the operator might operate the wrong control. It is important that the master valve be opened and closed at the correct times to avoid injuring personnel working on the high-pressure manifold and to avoid equipment damage caused by closing the master valve during pumping. The current system also requires the operator to leave the crane truck engine running during the frac job to have the hydraulic system available to open and close the master valve as required. This prolonged idling of the truck engines can cause problems with the diesel particulate filter on newer truck diesel-engine emissions systems and adds CO2 to the atmosphere.

A new hydraulic system to actuate the valves was designed to eliminate some of the problems of the current system. The new system uses an electric motor to drive a hydraulic pump to open and close the master valve. The electric motor is powered from the truck batteries. This allows the engine to be shut down for the majority of the frac job, reducing the diesel exhaust emitted to the atmosphere and extending maintenance intervals for the engine. Having an electric system also allows the master-valve controls to be placed on the other side of the truck, greatly reducing the chance the master valve will be accidentally actuated during WIT installation and removal. Typically, this also places the operator on the side of the truck away from the wellhead, which is a safer position (Fig. 1).

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