Patent Application
20190368310
In the resource recovery industry, it has been found that bitumen may exist in some deposits in a form too viscous for production in the traditional method. These deposits can be produced however using a process known in the art as Steam Assisted Gravity Drainage (SAGD). While the method is quite effective, it is known that steam breakthrough to the producing well is detrimental. Many efforts have been made to avoid such breakthrough and these all have utility but the art is always in search of alternative methods and apparatuses that that can account for particular situations or improve the effectiveness of the effort.
An autonomous valve including a housing; a chamber defined within the housing; and a piston in sealed movable contact with the housing, the piston having a piston area exposed to fluid within the chamber, and the piston having another piston area exposed to an environment outside of the housing.
A Steam Assisted Gravity Drainage (SAGD) System including a producer well having a valve as in any previous embodiment.
A method for controlling a Steam Assisted Gravity Drainage (SAGD) System including injecting steam through an injector well into a formation in thermal contact with the system; automatically admitting, reducing or denying entry of fluid to a producer well through a valve based upon both of temperature and pressure.
The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:
A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.
Referring to
System 10 is configured to require more than one physical property to which it is exposed to ensure activation at the appropriate time and only under appropriate conditions. More specifically, temperature alone or other parameter alone does not activate the system 10. Rather simultaneous parameters of temperature and pressure are required to activate the system 10. This will avoid erroneous closures that otherwise would limit production without need. The system 10 includes a tubular 12 having ports 14 (one or more ports, the depiction of several around the circumference of tubular 12 is not intended to be limiting). Tubular 12 is a part of a producer well and in an embodiment is a part of the production string 8 therein (see
While the autonomous valve 16 is illustrated in
The autonomous valve 16 is responsive to a combination of pressure and temperature but to neither alone. The exposed nature of piston 22 at end 26 to the ambient while the other end 24 of piston 22 is exposed to the chamber 20 means that in order for the piston to move, both temperature and pressure must be within certain parameters. This is related to the phase diagram/saturation curve of a fluid 34 contained within the chamber 20. All fluids have a phase diagram and a saturation curve where the gas phase is in equilibrium with the liquid phase for a given temperature and pressure acting on the particular fluid. A basic representation of a generic phase diagram/saturation curve is illustrated in
When conditions of the fluid in the chamber 20 change along the saturation curve line or into the liquid region, the piston 22 will move until equilibrium is again established. For example, the piston may move in the closing direction if temperature is increased or pressure is decreased from where either of those parameters were immediately prior or may move in the opening direction if temperature is decreased or pressure is increased from where either of those parameters were immediately prior. When the temperature is increased and the valve reaches its full stroke, the pressure in the chamber will climb, therefore keeping the valve closed. The effects of changes in pressure and temperature can also happen simultaneously. This is because whenever the system experiences a temperature and pressure that intersect somewhere along the saturation curve other than where on the saturation curve line the intersection was before the change, the equilibrium of fluid in the chamber 20 is lost and reestablishment of equilibrium may result in piston movement if at the new equilibrium the piston movement is not otherwise constrained by mechanical limits. The new equilibrium will include a different volume of the fluid 34 in the gas phase. Because the density of the gas phase is less than of the liquid phase, a greater or lesser occupancy of the chamber volume by one or the other (gas or liquid) will proportionally grow or contract the chamber causing the piston 22 to move toward or away from the ports 14, respectively. The degree of movement of piston 22 depends upon how far along the saturation curve the temperature and pressure intersection move from the immediately previous position limited, of course, by mechanical constraints of system 10. For any given pressure and temperature, the greater the distance between the intersection, the greater the movement of the piston 22 limited, of course, by mechanical constraints of system 10.
In embodiments, the autonomous valve 16 can be modified to react to the temperature and pressure in a different manner by incorporating a biasing member 36 (see
The foregoing embodiments generally have fluid in the chamber 20 that has the same saturation curve as the surrounding fluid such that as conditions allow the surrounding fluid to evolve steam, the fluid in the chamber will also evolve steam. This is advantageous for controlling the wellbore because the valve will restrict inflow when that inflow is evolving steam (or close to evolving steam if the piston is biased). Restricting steam can improve the overall well drawdown profile and also reduce equipment wear caused by the high velocity steam flow. In an alternate embodiment however, the composition of the fluid in the chamber 20 may be modified from the surrounding fluid so that the chamber fluid has a different saturation curve than the surrounding fluid. This will allow the chamber fluid to evolve steam earlier or later than the surrounding fluid to create an actuation of the piston in an advanced or delayed manner, respectively.
Set forth below are some embodiments of the foregoing disclosure:
Embodiment 1: An autonomous valve including a housing; a chamber defined within the housing; and a piston in sealed movable contact with the housing, the piston having a piston area exposed to fluid within the chamber, and the piston having another piston area exposed to an environment outside of the housing.
Embodiment 2: The valve as in any previous embodiment, wherein the piston includes a closure member.
Embodiment 3: The valve as in any previous embodiment, wherein the closure member is interactive with a port of a tubular, the closure member being configured to render the port open, choked or closed.
Embodiment 4: The valve as in any previous embodiment, wherein a portion of the housing is spaced from the tubular such that environmental fluid surrounds the portion of the housing during use.
Embodiment 5: The valve as in any previous embodiment, wherein the valve includes an insulator between the tubular and the housing.
Embodiment 6: The valve as in any previous embodiment, wherein the piston is movable based upon a combination of temperature and pressure applied to the valve.
Embodiment 7: The valve as in any previous embodiment, wherein the valve responds to changes in temperature depending upon the pressure.
Embodiment 8: The valve as in any previous embodiment, wherein the piston moves when pressure and temperature on a graph intersect at a point on a saturation curve line for a particular fluid in the chamber different than a point on the saturation curve line where temperature and pressure intersected immediately previously.
Embodiment 9: The valve as in any previous embodiment, wherein the piston extends from the housing when temperature and pressure intersect on the saturation curve line at a point consistent with more steam evolution than the point at which temperature and pressure intersected immediately previously.
Embodiment 10: The valve as in any previous embodiment, wherein the piston retracts into the housing when temperature and pressure intersect on the saturation curve line at a point consistent with less steam evolution than the point at which temperature and pressure intersected immediately previously.
Embodiment 11: The valve as in any previous embodiment, wherein the valve further includes a fluid in the chamber.
Embodiment 12: The valve as in any previous embodiment, wherein the fluid is selected to possess a particular saturation curve.
Embodiment 13: The valve as in any previous embodiment, wherein the fluid is selected to possess a different saturation curve than fluid surrounding the chamber.
Embodiment 14: The valve as in any previous embodiment, wherein the valve further includes a biasing member in bias transmitting connection with the piston.
Embodiment 15: The valve as in any previous embodiment, wherein the biasing member biases the piston to an extended position relative to the housing.
Embodiment 16: The valve as in any previous embodiment, wherein the biasing member biases the piston to a retracted position relative to the housing.
Embodiment 17: A Steam Assisted Gravity Drainage (SAGD) System including a producer well having a valve as in any previous embodiment.
Embodiment 18: The system as in any previous embodiment, further comprising a heated fluid source.
Embodiment 19: The system as in any previous embodiment, further including an injector well.
Embodiment 20: A method for controlling a Steam Assisted Gravity Drainage (SAGD) System including injecting steam through an injector well into a formation in thermal contact with the system; automatically admitting, reducing or denying entry of fluid to a producer well through a valve based upon both of temperature and pressure.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Further, it should be noted that the terms “first,” “second,” and the like herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The modifier “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., it includes the degree of error associated with measurement of the particular quantity).
The teachings of the present disclosure may be used in a variety of well operations. These operations may involve using one or more treatment agents to treat a formation, the fluids resident in a formation, a wellbore, and/or equipment in the wellbore, such as production tubing. The treatment agents may be in the form of liquids, gases, solids, semi-solids, and mixtures thereof. Illustrative treatment agents include, but are not limited to, fracturing fluids, acids, steam, water, brine, anti-corrosion agents, cement, permeability modifiers, drilling muds, emulsifiers, demulsifiers, tracers, flow improvers etc. Illustrative well operations include, but are not limited to, hydraulic fracturing, stimulation, tracer injection, cleaning, acidizing, steam injection, water flooding, cementing, etc.
While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited.
