Abstract:
The present inventions contemplate improved annular flow safety valve apparatus and methods in which the valve comprises a bi-directional self-contained electromechanically operated valve assembly including a moveable seal, power source, electric motor, and control system, capable of operating with or without power or control inputs from the surface.

Description:
TECHNICAL FIELD 
     The present invention relates to new devices and methods used in providing an electromechanically operated annular flow safety valve in the tubing of a cased subterranean well. 
     BACKGROUND OF THE INVENTIONS 
     Safety valves are used in subterranean wells to prevent uncontrolled fluid flow, which if not controlled could lead to equipment damage or a catastrophic well blowout. Conventional safety valves generally use a flapper mechanism with a sealing member in the form of a circular disc. Such safety valves are typically constructed with a bias spring mechanism maintaining a closed position, and a hydraulically operated actuator for moving the sealing member to an opened position. Similar safety valves with ball closure mechanisms are also known in the art. It is generally known to control safety valves with a wireline connection to the surface. Some valves have also been designed to close in response to a predetermined pressure. Examples of prior art safety valves are disclosed in U.S. Pat. Nos. 3,990,508; 4,160,484; 4,372,392; and 6,079,497. 
     Problems exist with downhole safety valves known in the art. Wireline control connections and hydraulic pressure sensors both impose limits on the operating environment of common safety valves. Two of the most important limitations are that of depth and pressure. Physical control connections are more difficult to maintain with increasing depth. Likewise, hydraulic systems are more difficult to operate at the high pressures often found in deep wells. Physical control and sensor mechanisms also have the serious disadvantage that it is required to remove the valve from the well to change pre-selected actuation parameters. Flapper valves are further limited by their one-directional nature. Flapper valves and ball valves are both subject to corrosion from particles that are often found suspended in well fluids. There is a need for improved safety valves with increased flexibility in terms of operating environment and control parameters. There is also a need for safety valves that will undergo minimized erosion damage during use. 
     SUMMARY OF THE INVENTIONS 
     The present inventions contemplate improved annular flow safety valve apparatus and methods in which the valve comprises a bi-directional self-contained electromechanically operated valve assembly including a moveable seal, power source, electric motor, and control system. The improved safety valve is capable of operating with or without power or control inputs from the surface. Features are also provided to decrease the erosive effect of solids suspended in the fluid stream. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings are incorporated into and form a part of the specification to illustrate several examples of the present inventions. These drawings together with the description serve to explain the principles of the inventions. The drawings are only for the purpose of illustrating preferred and alternative examples of how the inventions can be made and used and are not to be construed as limiting the inventions to only the illustrated and described examples. The various advantages and features of the present inventions will be apparent from a consideration of the drawings in which: 
     FIG. 1 is a longitudinal cross-sectional view of an annular flow safety valve apparatus in accordance with the inventions shown in the fully closed position; 
     FIG. 2 is a longitudinal cross-sectional view of an annular flow safety valve apparatus in accordance with the inventions in the fully open position; and 
     FIG. 3 is a schematic diagram of an example of a control assembly for an annular flow safety valve in accordance with the inventions. 
    
    
     DETAILED DESCRIPTION 
     The present inventions are described by reference to drawings showing one or more examples of how the inventions can be made and used. In these drawings, reference characters are used throughout the several views to indicate like or corresponding parts. 
     In the description which follows, like or corresponding parts are marked throughout the specification and drawings with the same reference numerals. The drawings are not necessarily to scale and the proportions of certain parts have been exaggerated to better illustrate details and features of the invention. In the following description, the terms “upper,” “upward,” “lower,” “below,” “downhole”, “longitudinally” and the like, as used herein, shall mean in relation to the bottom, or furthest extent of the surrounding wellbore even though the wellbore or portions of it may be deviated or horizontal. Correspondingly, the “transverse” orientation shall mean the orientation perpendicular to the longitudinal orientation. 
     In the description of the inventions, some terms referring to various aspects of operation of the apparatus are used. The word “actuation” is used to mean to manipulate or change state. The term “self-contained” means an autonomous unit having all working parts except as specifically indicated. Where components of relatively well-known design are employed, their structure and operation will not be described in detail. 
     Referring now primarily to FIGS. 1 and 2, the general structure and operation of the annular flow safety valve apparatus  10  utilizing the present inventive concepts is shown. A substantially tubular outer housing  12  of a size to fit inside the well casing  14  is deployed therein. The outer housing  112  has an upper end  16  and a lower end  18 . A nipple  20  is more or less concentrically disposed within the outer housing  12 . The nipple  20  has an upper end  22  proximal to the upper end  16  of the outer housing  12 , and extends in the direction of the lower end  18  of the outer housing  12 , terminating in a lower end  24 . A substantially annular fluid flow passage  26  is deformed between the outer surface  28  of the nipple  20  and the interior surface  30  of the outer housing  12 . A narrowing portion  32  of the outer housing  12  directs fluid flow, shown by the arrows, toward a plurality of ports  34  provided around the annulus of the upper end  22  of the nipple  20 . 
     The nipple has a lock mandrel seat  35  on the interior surface  28  of the nipple&#39;s upper end  22 . A seal assembly  136  is disposed within the nipple  20  and may extend past the lower end  24  of the nipple. The seal assembly  36  has a lock mandrel  37  secured to the mandrel seat  35 . The seal assembly  36  has a seal element  38 , preferably surfaced with an elastomeric material  40 . The seal element  38  is attached to the upper end  42  of a seal mandrel  44  moveable within a range between a fully closed position as shown in FIG. 1, and a fully opened position as shown in FIG.  2 . In the fully closed position (FIG.  1 ), the seal element  38  prevents fluid flow through the annular passage  26  by completely obstructing the ports  34  at the upper end  22  of the nipple  20 . In the fully opened position (FIG.  2 ), the seal element  38  does not obstruct the ports  34 , permitting fluid to flow freely through the annular passage  26 . The movement of the seal mandrel  44  is facilitated by an operable connection to a motor assembly  46  portion of the seal assembly  36 . The motor assembly  46  has an electric motor  48  operably connected to the moveable seal mandrel  42 , preferably with a ball screw mechanism  50 . 
     Further referring primarily to FIGS. 1 and 2, an electronic control assembly  52  has a control circuit  54  electrically connected to the motor  48 . The control circuit  54  preferably includes a microprocessor circuit  56  electrically connected to a telemetry circuit  58 . The telemetry circuit  58  is preferably designed to monitor physical parameters such as for example, location, temperature, flow, and pressure, and may contain sensor apparatus  60  known in the arts. The control circuit  54  preferably also contains a receiver circuit  62  for receiving signals from remote locations such as the wellhead (not shown). The electric motor  48  and control circuit  54  components are electrically connected to a downhole power source  64 , typically a storage battery. The motor assembly  46 , control assembly  54 , and power source  64  are preferably housed within an inner housing  66 , situated inside the nipple  20 , which includes a nosepiece  68  extending past the lower end  24  of the nipple. Optionally, the control assembly and power source may be located outside of the inner housing  66 , for example at the wellhead (not shown), and connected to the motor assembly via wire line (not shown). A plurality of lower ports  70  are provided between the outer surface  72  of the nosepiece  68  and the inner surface  30  of the outer housing  12 , which has a broadening portion  74  to facilitate fluid flow (indicated by the arrows) through the annular passage  26 . The nosepiece  68  is elongated, with the elongation preferably determined by the geometric relationship of the inside diameter of the outer housing  12  and the nosepiece angle  76 . It is known that a nosepiece angle  76  of approximately seven degrees provides favorable resistance to erosion by particles that may be suspended in the well fluid, such an angle is therefore preferred. 
     With reference primarily to FIG. 3, a schematic example of the operation of the preferred embodiment of the control assembly  52  is more particularly described. The motor assembly  46  contains an electric motor  48  mechanically connected to the ball screw (numeral  50 , FIGS. 1-2) of the annular flow safety valve apparatus  10  as follows. The control assembly  52  has a control circuit  54  electrically connected to the motor  48 . The control circuit  54  preferably includes a microprocessor circuit  56  electrically connected to a telemetry circuit  58 . The telemetry circuit  58  is designed to monitor physical phenomena such as for example, location, temperature, flow, and pressure, and may contain sensor apparatus  60  known in the arts such as quartz temperature and pressure transducers, for example. The electric motor  48  and control assembly  52  components are electrically connected to a downhole power source  64 , preferably a storage battery. 
     Referring now to the above description and FIGS. 1-3 in general, some aspects and advantages of the operation of the invention are generally described. The motor assembly and control assembly of the invention are preferably self-contained so that the annular flow safety valve apparatus includes a moveable seal, power source, electric motor, and control assembly, capable of operating together in response to predetermined parameters without need of power or control inputs from the surface. For example, the control assembly may be preconfigured to position the seal in the fully open position while a particular telemetry signal, typically pressure, is received. Upon loss of the telemetry signal, the motor is actuated and the seal is moved to the fully closed position. In an alternative configuration, the control assembly may be preconfigured to position the translating seal in the fully closed position when a particular telemetry signal is not received, and to actuate the motor moving the translating seal to the fully open position when a particular telemetry signal is received. In still other configurations, the control assembly may be preconfigured to respond to various signals or combinations of signals from the sensor apparatus, such as changes in pressure or flow rate, opening or closing the seal according to predetermined parameters. The microprocessor circuit may be used to perform calculations or logical operations on selected parameters detected by the sensor apparatus, actuating the movement of the seal element according to predetermined factors. Additionally, the receiver circuit included in the control assembly may be used to receive a remote signal, facilitating manual operation of the annular flow safety valve apparatus at the discretion of an operator at the surface. The receiver circuit may also be used to receive a remote signal used to reconfigure the internal instructions and settings of the microprocessor circuit in a manner known in the arts, enabling in-place adjustments to the actuation parameters of the annular safety apparatus. 
     The embodiments shown and described above are only exemplary. Many details are often found in the art such as: control assembly configurations and circuitry and seal element or housing materials. Therefore, many such details are neither shown nor described. It is not claimed that all of the details, parts, elements, or steps described and shown were invented herein. Even though numerous characteristics and advantages of the present inventions have been set forth in the foregoing description, together with details of the structure and function of the inventions, the disclosure is illustrative only, and changes may be made in the detail, especially in matters of shape, size and arrangement of the parts within the principles of the inventions to the full extent indicated by the broad general meaning of the terms used in the attached claims. 
     The restrictive description and drawings of the specific examples above do not point out what an infringement of this patent would be, but are to provide at least one explanation of how to make and use the inventions. The limits of the inventions and the bounds of the patent protection are measured by and defined in the following claims.