Wells – With electrical means – Electrical motor
Reexamination Certificate
1998-09-22
2001-03-13
Suchfield, George (Department: 3672)
Wells
With electrical means
Electrical motor
C166S065100, C166S302000
Reexamination Certificate
active
06199629
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a computer controlled intelligent downhole safety valve system. More particularly, the invention relates to a preferably electrically but possibly hydraulically, mechanically, electromechanically, electrohydraulically or pneumatically actuated and operated system comprising a safety valve and a plurality of sensors delivering information to and receiving instructions from a processor whether located locally or remotely from the valve.
2. Prior Art
Safety valves have been in existence for some time and have consistently been important to the safety of the environment and hydrocarbon drilling and production personnel.
Traditionally, safety valves have been hydraulically actuated and were operated from the surface based upon information gleaned from the production fluid or based upon dangerous conditions at the surface.
Hydraulically actuated safety valves commonly employ a flapper valve and a flow tube movable axially relative to the flapper valve. Thus, when the tube moves downhole the flapper is pushed open and the tube connects with more production tube downhole. As long as the flow tube remains in this downhole position the flapper stays open. The flow tube is biased however to an uphole position by a relatively high rate coil spring, the urging of which is overcome by hydraulic fluid pressure exerted from a reservoir, usually located at the surface. Necessarily there is a high pressure hydraulic fluid line extending from the reservoir to the valve which may be, for example, six thousand feet below the surface. Due to the large volume of hydraulic fluid that must be moved uphole in this fluid line, closing of the flapper is not as speedy as might be desired. Moreover, safety valves of this type, as stated above, are actuated only when conditions requiring a shut-in are perceptible at the surface.
More recently some work has been done to employ electric power to actuate and control safety valves. U.S. Pat. No. 5,070,944 to Hopper discloses a downhole electrically operated safety valve comprising an electric motor which drives a gear assembly having a drive gear and an operating gear, said gears providing a ratio of 30:1. The gears are operatively connected to a two-part drive sleeve the parts of which rotate together but are capable of relative axial movement. An actuating sleeve is also employed and a solenoid operated releasable lock prevents relative axial movement between the two parts of the drive sleeve.
Even with what may be considered more advanced electrically actuated downhole safety valves, the decision making is made at the surface depending upon information obtained at the surface. This limits the effectiveness of the safety valve because whatever condition indicates to the operator, from evaluation of production fluids, that the valve should close is a condition occurring through perhaps six thousand feet of pipe before the valve is shut. Therefore, there is a significant need for a system capable of obtaining information and rendering decisions downhole as well as being capable of communicating with other downhole tools, the surface and other wells. An example of a computer controlled safety valve and production well control system is disclosed in application Ser. No. 08/599,324 filed Feb. 9, 1996, all of the contents of which are incorporated herein by reference thereto.
SUMMARY OF THE INVENTION
The above-discussed and other drawbacks and deficiencies of the prior art are overcome or alleviated by the several methods and apparatus for providing computerized (“intelligent”) systems for operating, monitoring, controlling and diagnosing various parameters of downhole safety valve systems whether hydraulically actuated, hydraulically/electrically actuated or electrically actuated, electrically actuated systems being preferred. The systems disclosed provide the ability for the valve assembly to sense itself, sense its surrounding environment, make decisions and communicate with other downhole systems and surface systems on the same platform or on different platforms. Communication can even be provided between safety valves in different wells.
In order to provide an overview of the computer controlled intelligent systems contemplated in the present invention and their relation to the overall system for advanced hydrocarbon production, attention is directed to
FIG. 1
of the application.
FIG. 1
illustrates a pelagic situation having three platforms each with multiple lateralated wells and a communication system to provide a real time link between all of the wells. The system illustrated also embodies a number of downhole control systems that communicate downhole information to the surface and can receive information or instructions from the surface and from remote locations in communication with the surface.
In accordance with the present invention, a plurality of sensors are connected to processing units located downhole, uphole or both to provide sufficient input for the processors to carry out previously installed instructions or to develop databases of information collected over time. These data and processing units allow the safety valves of the invention to alter their own operational parameters to account for such time and environmental changes as the buildup of paraffin, scaling, sand etc., in the valve which might otherwise prevent its operation. The invention includes a downhole operated heater to melt and disperse paraffin as well as a current supplying device to remove scaling. These devices greatly enhance and improve longevity and operation of safety valves which, in turn, improves the safety of hydrocarbon production.
Other sensors and sensing arrangements allow intelligent systems to monitor potential problems requiring the alteration of other downhole tools. For example, water in the production fluid can be detected at the safety valve or even therebelow by sensors and therefore allow corrective action taken before the entire production tube to the surface is filled with contaminated production fluid. This enables a faster response and less down time. An example is a system that senses water and communicates with a sliding sleeve in a lateral well further downhole. This communication will trigger other intelligent operations which result in a particular sleeve closing or a group of sleeves closing to shut-in the offending reservoir. Moreover, the safety valve may need to close while the sleeves are moving and then reopen when the sliding sleeves are closed.
Moreover, the intelligent systems at or about the safety valve will more quickly shut-in that valve upon detection of an irregularity that could not have been detected at the surface for a significant period of time depending upon the distance of the tube above the valve. For some situations this will prevent a catastrophic disaster by shutting-in all wells on a platform or in an area by communication from valve to valve, if conditions warrant. Alternatively, the intelligent system of the invention can also understand the severity of any potential problem and communicate to other wells to increase production to make up for the shut-in well. This ability avoids loss of production and revenue.
Examples of sensory perception the safety valves of the invention will have regarding itself include: sensing the flow tube position and/or orientation, sensing the flapper position, sensing the amount of friction during movement of the flow tube or flapper valve and relatively the amount of power required to move these parts (this information is mapped to predict further movement parameters and future failure of the tool) and sensing a control signal (i.e., to ensure that the signal at the valve equals the signal initiated at the surface).
Examples of sensory perception afforded the safety valve of the invention relative to its environment include: Temperature at the valve, differential pressure across the valve, annulus pressure or temperature, leakage across the valve, tension and torque on valve components, bending moment o
Rawson Mike
Shaw Brian
Shirk Steve
Baker Hughes Incorporated
Cantor & Colburn LLP
Suchfield George
LandOfFree
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