A wellbore safety valve system includes a plug held by a retention spider, a plug seat separated from and located above the plug,Safety Valves and a controlled release section for separating the spider from the plug so that the plug can engage the plug seat. The controlled release section may be responsive to electrical energy from the surface, flow rate in the well, or acoustical energy.Balance Valves Safety apparatus for closing of well pipe extending from the earth surface down into earth formations where the safety apparatus operates to close in the well in response to abnormal well conditions comprising: a plug member positioned in the well pipe and located below the earth surface a valve seat spaced from and located near the plug member; means for retaining the plug in a position spaced from the valve seat, WATER POWER CONTROL VALVEsaid retaining means having a two part retaining member held together by a shear pin, and means for releasing the plug from the retaining means said releasing means being a velocity float mechanically connected to the retaining member and related shear pin. At the present time, there are several types of wellbore safety valves. These valves are designed to automatically shut in a well either when the rate of production from the well exceeds a predetermined rate, or when damage to surface equipment causes a draw-down of the bottom hole pressure. There are presently two basic methods of closing in a well with such a safety valve, because of excessive flow rate. One of the methods used to close in a well employs a valve mechanism operated by a velocity float in that when the velocity of produced fluids exceeds a predetermined level for which the float has been designed, the upward movement of the float causes the valve to close. The velocity float is itself the closing member, and is one of the first mechanisms utilized in closing in a well. The most common system of closing in tubing due to excessive producing rates utilizes a pressure differential across an orifice for activating a spring which closes a conventional valve or rotates a ball valve having a flow channel therethrough so that the flow channel no longer is aligned with the path of produced fluids. There are a few valves available which are responsive to surface conditions. One such valve operates when the well pressure drops below a predetermined amount. Thus, if the wellhead or flow lines are damaged and result in a decline in well pressure, the valve will close. This is usually accomplished by precharging a chamber so that the pressure in the chamber and the pressure in the tubing is equal. Upon a drop in well pressure, differential pressure between the precharged chamber and the pressure in the tubing activates a piston to close the valve. Another surface condition reactive valve which is also operated from the surface has been made available by Otis Engineering Corporation. The Otis valve utilizes a hydraulic line which extends from the surface to the downhole valve. Surface monitoring equipment or manual controls can act on the hydraulic system to close the valve. The hydraulic line extends down the side of the tubing and is attached to a special sub which houses the valve. Various valves are available on the market which operate utilizing a hydraulic system; however all these valves have metal to metal movement which can become eroded or jammed by sand or other wellbore comaminants.

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