Chemical Bypass for a Packer in a Wellstring

Abstract

A packer assembly for a production well is described. The packer assembly includes one or more packer elements set to engage and seal the inner surface of a well casing, where a production tube runs through the one or more packer elements and provides a fluid path to the surface. A chemical inlet above the one or more packer elements connects to a chemical flow path through the one or more packer elements and a chemical outlet below the packer assembly.

Description

CROSS REFERENCE TO RELATED INFORMATION

This application claims the benefit of U.S. Provisional Patent Application No. 63/322,981, filed Mar. 23, 2022, titled Chemical Bypass for a Packer in a Wellstring, the contents of which are hereby incorporated herein in its entirety.

TECHNICAL FIELD

The present disclosure is directed to downhole tools for oil and gas production and more specifically to a chemical bypass for a downhole packer assembly.

BACKGROUND OF THE INVENTION

Petroleum wells can be naturally flowing, injecting or can be produced by any means of artificial lift. Such artificial lift in a production well may be produced by, but is not limited to, an electrical submersible pump (ESP), a sucker rod pump, and/or a progressing cavity pump. For instance, an ESP system may include an electric motor and a pump that is used to pump oil or other liquids within a wellbore. The electric motor may have a rotatable rotor that is contained in a stationary stator. When the motor operates, the rotor may rotate to provide artificial lift within the wellbore.

While any type of natural or artificial lift may be used, to illustrate the basic structure of an oil and gas well, a typical well using and ESP is shown in FIG. 1. Referring to FIG. 1, a diagram of a typical ESP system (100) includes a centrifugal pump (101), a pump motor (105), and a seal assembly (103) located between the pump (101) and motor (105). The pump (101), seal assembly (103), and motor (105) are located within a borehole (121), inside a standard well casing (123). The ESP system (100) further includes a variable speed drive (111), a controller (113), and an optional transformer (115) located on the surface (125). A three-phase power cable (117) provides power and communications between the variable speed drive (111) (or optional transformer (115)) and the pump motor (105). The variable speed drive (111) can operate as a power source by providing electrical power for driving the motor (105). The cable (117) typically extends thousands of feet and thereby introduces significant electrical impedance between the variable speed drive (111) (or optional transformer (115)) and the pump motor (105). By altering the output voltage and frequency of the variable speed drive (111), the controller (113) associated with the variable speed drive (111) controls the voltage at motor (105) terminals, and thus the operation of the pump.

A packer is a tool used in oil and gas wells, which when set, seals the well bore or seals space between the well casing and the production string. Packers start with an initial outside diameter smaller than the casing and when in the desired location, expanded to seal the casing or well bore using flexible elastomeric elements or mechanical expanders with sealing elements. The packer isolates sections of the well from one another preventing the flow of liquids or gasses through the well bore except through the production string. While this isolation is in most instances the desired outcome or beneficial, in some circumstances it may still be desirable to introduce materials into the well past the packer assembly.

For example, in many instances it is desirable to treat the oil and gas product in the well with chemicals by providing a constant stream of those chemicals into the well fluid and gas. Those chemicals can include defoamers, demulisfiers, diesel, coolant or other chemical that can increase the performance of or otherwise aid the well, such as by helping remove gas entrained in the well liquid. One problem in delivering chemicals into the well product is that there may be packers in the well string that prevent liquid and gas from flowing up or down around the packer. To get chemicals to the well product there needs to be a mechanism to bypass the packer assemblies with the stream of chemical product.

BRIEF SUMMARY OF THE INVENTION

In an embodiment of the concepts described herein, a packer assembly for a production well is described. The packer assembly includes one or more packer elements set to engage and seal the inner surface of a well casing, where a production tube runs through the one or more packer elements and provides a fluid path to the surface. A chemical inlet above the one or more packer elements connects to a chemical flow path through the one or more packer elements and a chemical outlet below the packer assembly.

In another embodiment, a chemical bypass for a packer assembly in a production well is described. The chemical bypass includes an input port having an input connector to connect to a chemical line running from chemical source. A bypass line connects to the input port and provides a chemical flow path through the packer assembly, where the packer assembly seals a well casing in the production well. An output port connects to the bypass line, the output port connecting to the chemical line below the packer assembly through an output connector.

The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram of a petroleum producing well;

FIG. 2 is a cut-away view of a chemical bypass in a tube in a well bore in a petroleum producing well according to the concepts described herein;

FIG. 3 is diagram of an embodiment of a chemical bypass system in a well bore according to the concepts described herein; and

FIG. 4 is a diagram of an alternate embodiment of a chemical bypass system according to the concepts described herein.

DETAILED DESCRIPTION OF THE INVENTION

In many circumstances the liquids and gases produced by a oil and gas well are in a condition detrimental to pumping. In such circumstances it would be beneficial to the performance of the well to treat the well products with various chemicals, such as defoamers, demulisfiers, diesel, coolant or other chemical that can increase the performance of or otherwise aid the well. For example, using a defoamer or demulsifier, this would allow for the breaking of the gas out of solution and allows for a heavier fluid to enter the bottom hole assembly consistently, fill the pump and achieve higher production rates and cooler motor temps than previously seen. Slip streaming and batch treating, the typical prior ways of chemically treating wells, is not only temporary but also rarely gets all the way down to the intake and is impossible to get below a packer assembly sealing the well bore.

FIG. 2 shows an embodiment of a chemical bypass in a packer assembly. The packer seals the casing at a desired point in the well string to prevent the movement of liquid and gas up the casing or down the casing past that point. Blocking the casing with a packer can be used in a variety of situations, including to isolate a portion of the well or certain production zones in the well.

Referring now to FIG. 2, an embodiment of a chemical bypass for a well bore packer is shown. A packer assembly 200 is shown in a well casing 123. Packer assembly 200 includes production tubing 201 which carries the production liquids from the well to the surface. The production tubing is connected to the greater well string using top connector 202 and bottom connector 203. Packers 204 and 205 are expandable elastomeric elements that are expanded at the desired location and seal the well casing preventing fluids and gasses from flowing either up or down the well casing. O-ring 206 connects packers 204 and 205 and provides stability to the assembly 200.

A chemical bypass is formed by bypass line 211 in the assembly that provides a pathway for chemicals to pass from above the packer assembly to below the packer assembly. Input port 207 provides access to bypass line 211. Input connector 209 provides a connection to a chemical line (not shown) running from the surface or other location to the packer assembly 200. Similarly, output port 208 provides a fluid path out of bypass line 211 into the well casing below the packer assembly. Output connector 210 can be connected to a chemical line to feed the chemical to the desired depth in the well casing.

The chemical bypass provides for the ability to pump a constant drip of a chemical, such as a defoamer/demulsifier/diesel/coolant or other chemical, down the casing via the cap string to below the packer on a consistent basis. The chemical bypass allows the cap string to be terminated at top of packer, the chemical then travels via an isolated path through the inner diameter of the packer where it exits bypass back into casing annulus below packer assembly. While the chemical flow path of bypass line 211 is shown running through the interior of production tubing 201, other configurations are possible where the flow path flows through a different portion of the packer assembly or takes something other than a straight path through the packer. For example, the flow path could also run along the wall of the production tubing or along the outside of the tubing so long as a fluid path is formed that flows from above the packer assembly to below the packer assembly.

The packer includes a chemical bypass that connects to a chemical injection line at the chemical line input. The chemical can then flow through the chemical flow path and then out the chemical line outlet. The chemical line outlet can connect to another chemical line or tubing that can then deliver the chemical to the desired point in the wellbore.

While a particular type of packer assembly is shown in FIG. 2, there are many distinct types of packer assemblies all of which can be modified to accommodate a chemical bypass line. FIGS. 3 and 4 show that the chemical bypass concept described herein is applicable to all types of packers and packer assemblies or other devices that are meant to seal the well. FIG. 3 shows a cup packer assembly incorporating a chemical bypass line. Chemical line 312 runs along well string 314 and connects to input port 207 using input connector 209. The chemical bypass then runs through the production tubing through cup packers 204 and 205 and connector 206 before flowing out of output port 208 through output connector 210 and into chemical line 313 which runs along the well string to inlet 315. Outlet 314 allows the chemical to then flow into well bore and mix with the well liquids and gasses.

FIG. 4 shows a tension style packer assembly. The tension packer has a single set of unidirectional slips 416 that lever outwards from cap 415. Slips 416 grip only the casing when the tubing is pulled in tension. Constant tubing tension must be maintained to keep the packer set and the packing element energized. Flexible packing element 417 provides the seal with casing 123. Tension packers, typically, are set mechanically and are released by means of tubing rotation. As before, input port 207 connects to chemical line 312 and connects to the chemical bypass path through the packer assembly. The chemical then flows out of output port 208 and into downhole chemical line 313.

As can be seen from the preceding examples, adding a chemical bypass path through any type of packer assembly is well within the concepts described herein.

Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims

1. A packer assembly for a production well comprising:

one or more packer elements set to engage and seal the inner surface of a well casing;

a production tube running through the one or more packer elements and providing a fluid path to the surface;

a chemical inlet above the one or more packer elements;

a chemical flow path through the one or more packer elements; and

a chemical outlet below the packer assembly.

2. The packer assembly of claim 1 wherein the chemical inlet is connected to a chemical line bringing a chemical from a surface supply by an input connector.

3. The packer assembly of claim 1 wherein the packer assembly comprises a cup packer.

4. The packer assembly of claim 1 wherein the packer assembly comprises a tension packer.

5. The packer assembly of claim 2 wherein the chemical comprises one or more of a defoamer, a demulisfier, diesel, a coolant.

6. The packer assembly of claim 1 wherein the chemical flow path comprises a bypass line running through an interior of the production tube.

7. The packer assembly of claim 1 wherein the chemical flow path comprises a bypass line running through an exterior of the production tube.

8. The packer assembly of claim 1 wherein the chemical flow path comprises a bypass line integral to a wall of the production tube.

9. A chemical bypass for a packer assembly in a production well, the chemical bypass comprising:

an input port having an input connector to connect to a chemical line running from chemical source;

a bypass line connected to the input port, the bypass line providing a chemical flow path through the packer assembly, the packer assembly sealing a well casing in the production well.

an output port connected to the bypass line, the output port connecting to the chemical line below the packer assembly through an output connector.

10. The chemical bypass of claim 9 wherein a production tube runs through the packer assembly and provides a fluid path for a well fluid.

11. The packer assembly of claim 9 wherein the packer assembly comprises a cup packer.

12. The packer assembly of claim 9 wherein the packer assembly comprises a tension packer.

13. The packer assembly of claim 9 wherein the chemical line carries a chemical, the chemical including one or more of a defoamer, a demulisfier, diesel, a coolant.

14. The packer assembly of claim 10 wherein the bypass line runs through an interior of the production tube.

15. The packer assembly of claim 10 wherein the bypass line runs through an exterior of the production tube.

16. The packer assembly of claim 10 wherein the bypass line is integral to a wall of the production tube.