Tubing strings used downhole typically maintain isolation between the surface and a producing region or isolate producing regions from each other. In some applications these valves can be used as safety valve. There are several types employed with some of the more popular being a rotating 90 degree ball with a passage therethrough or a pivoting valve member known as a flapper that is moved away from a mating seat with a hollow tube known as a flow tube. The flow tube is operated from the surface using control lines that transmit hydraulic pressure from the surface to an operating piston in the valve housing that is in turn connected to the flow tube. In the case of the 90 degree ball valves, the ball turns on a pivot and is surrounded by a cage-like structure that is actuated from the surface through control lines that engage a piston or pistons for cage movement in opposed directions. One such control system for a 90 degree ball is shown in US Publication 20080110632. One issue with this design is that the cage system that rotates the ball is exposed to well fluids and can get caked up to an extent that may interfere with its future operation. The cage generally has to be precision fabricated and assembled and its reliance on actuating pistons greatly increases the overall housing length of the tool.
In the past ball valves have been used as lubricator valves. They generally featured a pair of control lines to opposed sides of a piston whose movement back and forth registered with a ball to rotate it 90 between an open and a closed position. Collets could be used to hold the ball in both positions and would release in response to control pressure in one of the control lines. An example of such a design can be seen in U.S. Pat. Nos. 4,368,871; 4,197,879 and 4,130,166. In these patents, the ball turns on its own axis on trunnions. Other designs translate the ball while rotating it 90 degrees between and open and a closed position. One example of this is the 15K Enhanced Landing String Assembly offered by the Expro Group that includes such a lubricator valve. Other designs combine rotation and translation of the ball with a separate locking sleeve that is hydraulically driven to lock the ball turning and shifting sleeve in a ball closed position as shown in U.S. Pat. No. 4,522,370. Some valves are of a tubing retrievable style such as Halliburton's PES® LV4 Lubricator Valve. Lock open sleeves that go through a ball have been proposed in U.S. Pat. No. 4,449,587. Other designs, such as U.S. Pat. No. 6,109,352 used in subsea trees have a rack and pinion drive for a ball and use a remotely operated vehicle (ROV) to power the valve between open and closed positions claiming that either end positioned is a locked position but going on to state that the same ROV simply reverses direction and the valve can reverse direction.
What is needed and not provided in the known prior art is a way to operate a downhole valve in a manner that simplifies the actuation design and preferably isolates it from the surrounding well fluid. In the preferred embodiment portions of the string are secured to each other for relative movement so that when such movement occurs the valve moves in a first direction and when such movement is reversed the valve moves in the opposite direction. This can be accomplished by relative rotation between string components that are held together. In one embodiment the relative string rotation is translated through a slanted slot and ball combination to deliver a turning moment to the valve member as the ball in the slot travels along the slot. The same result can be obtained using a j-slot mechanism between string components that induces relative rotation between string components that are otherwise held together as in the first example where the relative rotation directly induces valve member movement as opposed to indirectly such as using a j-slot device or equivalent to induce valve member movement. In the preferred embodiment the valve member is a ball with a passage through it but other forms of valve members are contemplated. Those skilled in the art will more readily appreciate the invention from a review of the description of the preferred embodiment and the associated drawings while understanding that the full scope of the invention is to be determined by the appended claims.
USPTO Backgrounds
USPTO Backgrounds