WELL FLOW CONTROLLING SYSTEMS, METHODS AND APPARATUS

A well flow controlling system, method and apparatus for wells having a plurality of flow conductors therein for establishing flow communication between pairs of the flow conductors at a point down-hole in the well by opening normally closed valve means and positively holding the valve means open during operations of circulating or flowing fluids through the conductors in the well until it is desired to close the valve to shut off flow communication between the pairs of conductors. The valve is pressure operable to open position by pressure of fluids in the conduits and is held open mechanically to permit the flow or circulation of fluids at pressures lower than the pressure required to open the valve. The valve is also fluid pressure operable for movement to closed position. A pressure responsive valve for controlling fluid flow between a pair of well flow conduits connected together by a cross-flow passage at a subsurface point in a well to provide U-tube flow communication between the conduits to permit circulation of fluids through the conduits to move well tools into and out of the well through one or the other of the conduits or to perform other service or production operations in the well. The valve is positively mechanically held in open position when moved to such open position to permit circulation of fluids at pressures lower than the pressures required to move the valve to open or closed positions.