Title:
SYSTEM AND METHOD FOR POLYMER DISTRIBUTION TO WELL SITES
Kind Code:
A1


Abstract:
The invention relates to a polymer transport and distribution system comprising a vessel, pipeline or network of pipes containing polymer mother solution, and one or more pumps for transporting polymer mother solution from a first location to one or more injection well sites at a second remote location, each injection well comprising a polymer mother solution input feed line, a water input feed line, and a second pump for controlling mother solution flow rate and pressure upstream from the water input feed line, for producing polymer daughter solution from polymer mother solution and water, and injecting the resulting polymer daughter solution into an oil or gas field well. Also provided are methods of distributing polymer to one or more injection well sites in an oil or gas field.



Inventors:
Van Beurden, Jorgen (Calgary, CA)
Falez, Brad (Calgary, CA)
Markwart, Chris (Calgary, CA)
Reid, Cary G. (Calgary, CA)
Chan, Chong (Calgary, CA)
Laurin, Art (Calgary, CA)
Starr, Brian (Calgary, CA)
Mackinnon, Murray (Calgary, CA)
Remtulla, Farid (Calgary, CA)
Application Number:
12/255478
Publication Date:
10/01/2009
Filing Date:
10/21/2008
Primary Class:
Other Classes:
166/90.1, 166/305.1
International Classes:
E21B43/16; E21B43/20; E21B43/25
View Patent Images:
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Primary Examiner:
LEFF, ANGELA MARIE DITRAN
Attorney, Agent or Firm:
CLARK & ELBING LLP (BOSTON, MA, US)
Claims:
What is claimed is:

1. A polymer transport and distribution system comprising, a vessel, pipeline or network of pipes containing polymer mother solution, and; one or more pumps for transporting polymer mother solution from a first location to one or more injection well sites at a second remote location, each injection well comprising a polymer mother solution input feed line, a water input feed line, and a second pump for controlling mother solution flow rate and pressure upstream of the water input feed line, and for producing polymer daughter solution from polymer mother solution and water, and injecting the resulting polymer daughter solution into an oil or gas field well.

2. The polymer transport and distribution system of claim 1, further comprising at least one mixer for mixing polymer mother solution with water.

3. The polymer transport and distribution system of claim 1, wherein the polymer comprises polyacrylamide, hydrolysed polyacrylamide, xanthan gum, guar gum, diutan gum, welan gum or a combination thereof.

4. The polymer transport and distribution system of claim 3, wherein the polymer comprises a viscosity in the range of about 1 to about 25000 cP.

5. The polymer transport and distribution system of claim 1, wherein either the polymer mother solution, the polymer daughter solution or both comprise less than about 50000 ppm total dissolved solids.

6. The polymer transport and distribution system of claim 1, wherein the polymer mother solution, polymer daughter solution or both comprise a surfactant, biocide, alkaline component, antifoaming agent, or a combination thereof.

7. The polymer transport and distribution system of claim 1, wherein the polymer daughter solution comprises polymer mother solution diluted with water.

8. The polymer transport and distribution system of claim 8, wherein said water is derived from a saline well, a freshwater well, a water filtration skid or a combination thereof.

9. The polymer transport and distribution system of claim 1 further comprising one or more of: a) a dry polymer holding vessel; b) a dry polymer transfer system; c) a water inlet source for hydrating dry polymer; d) an input source for adding one or more additional components to the dry polymer, water or polymer mother solution, e) a mixer for preparing polymer mother solution, and; g) a polymer mother solution holding vessel.

10. The system of claim 9, comprising a dry polymer polymer transfer system, wherein said system comprises a calibrated auger or a helix conveyor.

11. The system of claim 10, wherein the system comprises a mixer.

12. A polymer transport and distribution system comprising, a dry polymer transfer system, a water inlet source, and a first mixer for preparing a polymer mother solution from said dry polymer and water, one or more pumps for transporting polymer mother solution through a pipeline or network of pipes to one or more remote injection pod sites, each injection pod site comprising, one or more injection wells, each injection well comprising a polymer mother solution input feed line and a water input feed line to produce polymer daughter solution, and a pump for controlling mother solution flow rate and pressure upstream of the water input feed line, for injecting the resulting polymer daughter solution into a well.

13. A method of distributing polymer to one or more injection well sites in an oil or gas field comprising, a) providing a polymer mother solution; b) pumping the polymer mother solution through a pipeline or network of pipes from a first location to one or more remote locations comprising at least one injection pod or well site; c) mixing the polymer mother solution with water and optionally one or more additional components to form a polymer daughter solution and; d) injecting the polymer daughter solution into a well.

14. A method of distributing polymer to one or more injection well sites in an oil or gas field comprising, a) storing or producing a polymer mother solution in a polymer processing station; b) pumping the polymer mother solution through a pipeline or network of pipes from the polymer processing station to one or more remote injection pods or injection well sites; c) mixing the polymer mother solution with water and optionally one or more additional components at the injection pod or injection well contained therein to form a primary polymer daughter solution and; d) injecting the primary polymer daughter solution into the injection well; e) extracting oil or gas from a producer well in fluid communication with the injection well, and; f) optionally, mixing polymer mother solution with water and if desired, one or more additional components at the injection pod or injection well site contained therein to form a secondary polymer daughter solution, wherein the secondary polymer daughter solution is more dilute in polymer concentration and less viscous than the primary daughter solution, g) injecting the secondary daughter polymer solution into the injection well; h) extracting oil from the producer well in fluid communication with the injection well, and; i) optionally repeating steps f)-h) using successively more dilute and less viscous daughter solutions.

Description:

FIELD OF INVENTION

The present invention relates to oil and gas recovery. More specifically, the present invention relates to polymer use in oil and gas recovery.

BACKGROUND OF THE INVENTION

Polymer compounds are used in the oil industry to prevent fingering in subterranean oil formations. In most cases, polymer solutions are prepared at each well site and the resulting formulation is injected into a well. As most oil fields comprise several injector-producer wells, there is often a need to inject polymer into several wells within the field. Typically, at each injection well, dry polymer powder is mixed with an appropriate quantity of water and the resulting solution is injected into the well. This approach requires dry polymer to be transported to the various well sites. Further, mixing systems, polymer holding tanks and the like must be stationed at each well site where polymer is injected. This requires transportation systems such as roads and other types of costly infrastructure to be implemented to ensure that the proper components and products are present at the appropriate locations and at the appropriate times. Further, this type of approach must be monitored closely to ensure a continuous supply of dry polymer for injection and also to ensure the mechanical components required for injection at each point are working properly.

There is a need in the art for novel polymer transportation and distribution systems in oil and gas fields. Further, there is a need for systems and methods of preparing polymer at a central location and transporting the same, potentially over large distances to several well sites where the polymer may be diluted if necessary to a desired viscosity and pumped down-well.

SUMMARY OF THE INVENTION

The present invention relates to oil and gas recovery. More specifically, the present invention relates to polymer use in oil and gas recovery.

According to the present invention, there is provided a polymer transport and distribution system comprising,

    • a vessel, pipeline or network of pipes containing polymer mother solution, and;
    • one or more pumps for transporting polymer mother solution from a first location to one or more injection well sites at a second remote location, each injection well comprising a polymer mother solution input feed line, a water input feed line, a second pump for controlling mother solution flow rate and pressure, the second pump upstream of the water input feed line, for producing polymer daughter solution from polymer mother solution and water, and injecting the resulting polymer daughter solution into an oil or gas field well.

Also according to the present invention, there is provided a polymer transport and distribution system comprising,

    • a vessel, pipeline or network of pipes containing polymer mother solution, and;
    • one or more pumps for transporting polymer mother solution from a first location to one or more injection well sites at a second remote location, each injection well comprising a polymer mother solution input feed line, a high pressure dilution water input feed line, and a second pump for controlling mother solution flow rate and pressure, upstream of the high pressure dilution water input feed line for producing polymer daughter solution from polymer mother solution and water, and injecting the resulting polymer daughter solution into an oil or gas field well.

Also provided is a polymer transport and distribution system as defined above, further comprising at least one mixer for mixing polymer mother solution with water.

The present invention also contemplates a polymer transport and distribution system as defined above, wherein the polymer comprises polyacrylamide, hydrolysed polyacrylamide, xanthan gum, guar gum, diutan gum, welan gum or a combination thereof.

Also provided is a polymer transport and distribution system as defined above, wherein the polymer comprises a viscosity in the range of about 1 to about 25000 cP.

The present invention further contemplates a polymer transport and distribution system as defined above, wherein either the polymer mother solution, the polymer daughter solution or both comprise less than about 50000 ppm total dissolved solids. In an embodiment, which is not meant to be limiting, the polymer mother solution, polymer daughter solution or both comprise less than about 25000 ppm, more preferably less than about 18000 ppm total dissolved solids. In a further embodiment, which is not meant to be limiting, the polymer mother solution, polymer daughter solution or both comprise less than 5000 ppm total dissolved solids.

Also provided by the present invention is a polymer transport and distribution system as defined above, wherein the polymer mother solution, polymer daughter solution or both comprise a surfactant, biocide, alkaline component, antifoaming agent, or a combination thereof.

The present invention also contemplates a polymer transport and distribution system as defined above, wherein the polymer daughter solution comprises polymer mother solution diluted with water.

Also provided by the present invention is a polymer transport and distribution system as defined above, wherein the water is derived from a saline well, a freshwater well, a water filtration skid or a combination thereof.

The present invention also contemplates a polymer transport and distribution system further comprising one or more of:

    • a) a dry polymer holding vessel;
    • b) a dry polymer transfer system;
    • c) a water inlet source for hydrating dry polymer;
    • d) an input source for adding one or more additional components to the dry polymer, water or polymer mother solution,
    • e) a mixer for preparing polymer mother solution, and;
    • g) a polymer mother solution holding vessel.

Also provided by the present invention is a polymer transport and distribution system as defined above that comprises a dry polymer polymer transfer system, wherein the system comprises a calibrated auger or a helix conveyor. Also, the system may further comprise a mixer.

The present invention also contemplates a polymer transport and distribution system comprising,

    • a dry polymer transfer system, a water inlet source, and a first mixer for preparing a polymer mother solution from said dry polymer and water,
    • one or more pumps for transporting polymer mother solution through a pipeline or network of pipes to one or more remote injection pod sites, each injection pod site comprising,
    • one or more injection wells, each injection well comprising a polymer mother solution input feed line, one or more pumps for controlling mother solution flow rate and pressure upstream of a water input feed line, preferably a high pressure dilution water input feed line, to produce polymer daughter solution for injection into a well.

The present invention also provides a method of distributing polymer to one or more injection well sites in an oil or gas field comprising,

    • a) providing a polymer mother solution;
    • b) pumping the polymer mother solution through a pipeline or network of pipes from a first location to one or more remote locations comprising at least one injection pod or well site;
    • c) mixing the polymer mother solution with water and optionally one or more additional components to form a polymer daughter solution and;
    • d) injecting the polymer daughter solution into a well.

The present invention also provides a method of distributing polymer to one or more injection well sites in an oil or gas field comprising,

    • a) storing or producing a polymer mother solution in a polymer processing station;
    • b) pumping the polymer mother solution through a pipeline or network of pipes from the polymer processing station to one or more remote injection pods or injection well sites;
    • c) mixing the polymer mother solution with water and optionally one or more additional components at the injection pod or injection well contained therein to form a primary polymer daughter solution and;
    • d) injecting the primary polymer daughter solution into the injection well;
    • e) extracting oil or gas from a producer well in fluid communication with the injection well, and;
    • f) optionally, mixing polymer mother solution with water and if desired, one or more additional components at the injection pod or injection well site contained therein to form a secondary polymer daughter solution, wherein the secondary polymer daughter solution is more dilute in polymer concentration and less viscous than the primary daughter solution,
    • g) injecting the secondary daughter polymer solution into the injection well;
    • h) extracting oil from the producer well in fluid communication with the injection well, and;
    • i) optionally repeating steps f)-h) using successively more dilute and less viscous daughter solutions.

This summary of the invention does not necessarily describe all features of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings wherein:

FIG. 1 shows a representative embodiment of a polymer transport and distribution system according to the present invention.

DETAILED DESCRIPTION

The following description is of a preferred embodiment.

The present invention will be further illustrated in the following examples.

According to an embodiment of the present invention, there is provided a polymer transport and distribution system comprising,

    • a vessel, pipeline or network of pipes containing polymer mother solution;
    • one or more pumps for transporting polymer mother solution from a first location to one or more injection well sites at a second remote location, each injection well comprising a polymer mother solution input feed line, a water input feed line, and a second pump for controlling mother solution flow rate and pressure, preferably at or upstream of the water input feed line, for producing polymer daughter solution from polymer mother solution and water, and injecting the resulting polymer daughter solution into an oil or gas field well.
      In a preferred embodiment, the water input feed line is a high pressure dilution input feed line.

In a preferred embodiment, which is not meant to be limiting in any manner, there is provided a polymer transport and distribution system comprising,

    • a vessel containing a polymer mother solution;
    • one or more pumps for transporting polymer mother solution from the vessel through a pipeline or network of pipes to one or more injection pod sites, each injection pod site comprising,
    • a second pump for controlling mother solution flow rate and pressure upstream of a high pressure dilution water input feed line used to produce polymer daughter solution from polymer mother solution and water, the water optionally derived from a vessel, pipeline or network of pipes carrying water, and injecting the resulting polymer daughter solution into an oil or gas field well.

It is to be understood that the polymer transport and distribution system may further comprise a mixer that mixes the polymer mother solution with water to produce polymer daughter solution. Inclusion of a mixer is optional as the combination of polymer mother solution with water to make polymer daughter solution and the subsequent injecting of the polymer daughter solution into an oil and gas field well is usually sufficient to ensure thorough mixing. However, there are instances whereby it may be desirable to include a mixer, for example, but not limited to, when the viscosity of the polymer mother solution is high compared to that of water or in instances when the polymer mother solution is diluted by either a very small or very large amount. A person of skill in the art would be able to determine if a mixer should be included in the polymer transport and distribution system having regard to the information provided herein.

By the term “polymer mother solution” it is meant an aqueous solution comprising a polymer, water and optionally one or more additional components. The polymer may comprise any polymer known in the art, for example, but not limited to polyacrylamide including, but not limited to hydrolyzed polyacrylamide, xanthan gum, guar gum, diutan gum, welan gum or a combination thereof. In an embodiment of the present invention, which is not meant to be limiting in any manner, the polymer mother solution comprises a polyacrylamide polymer. In an alternate embodiment, the polymer mother solution comprises xanthan gum. In still a further embodiment, which is not meant to be limiting, the polymer mother solution comprises guar gum. However, it is to be understood that other types of polymers, biopolymers, viscosifying agents or any combination thereof may be employed in the present invention. Accordingly, the list of polymers provided above is not meant to be limiting in any manner.

The polymer mother solution preferably has a viscosity in the range of about 1 to about 25000 cP, more preferably about 5 to 15000 cP and still more preferably about 10 to about 10000 cP. For example, the polymer mother solution may comprise a viscosity of about 1, 5, 10, 50, 100, 500, 1000, 2000, 5000, 10000, 15000, 20000, 25000 cP or any amount therein between. Further, the viscosity of the polymer mother solution may be defined by a range of any two of the values provided above or any amounts therein between. However, a polymer mother solution comprising characteristics outside one or more of these ranges is also contemplated.

The viscosity of polymer mother solution may be measured according to known methods in the art, and any such method may be employed to determine the viscosity of the polymer solutions as defined herein. For example, but not to be considered limiting in any manner, viscosity may be measured in accordance with the American Petroleum Institute (API) Recommended Practice 63 (RP63), First Edition, Jun. 1, 1990, which is hereby incorporated by reference.

In embodiments wherein the polymer mother solution comprises polyacrylamide polymer, it is preferred that the solution does not comprise water with high levels of total dissolved solids, particularly cationic or divalent species as these components can inhibit hydrolysis of polymer and/or breakdown the viscosity of such polymer solutions. In embodiments wherein polyacrylamide polymer is employed in the polymer transport and distribution system, preferably the total dissolved solids is less than about 5000 ppm, more preferably less than 2000 ppm.

By the term “total dissolved solids” it is meant the sum of anions and cations from water analysis. Cations may be determined by Inductively Coupled Plasma (ICP) using American Public Health Association (APHA) 3120 method. Chloride may be determined by titration (APHA 4500-C1:B), sulfate by APHA 3120 and alkalinity by titration according to APHA 2320:B. Alternatively, other methods to measure total dissolved solids as would be known to a person of skill in the art may be employed.

As xanthan gum polymers exhibit increased resistance to viscosity breakdown in the presence of salts, the use of such polymers is preferred in instances wherein the polymer is mixed with water that comprises a high content of total dissolved solids, salts, iron, iron-containing species, or a combination thereof. In a preferred embodiment, which is not meant to be limiting in any manner, xanthan gum polymers are employed in polymer compositions wherein the content of total dissolved solids (excluding polymer) is greater than about 2000 ppm.

As described previously, it is also contemplated that the polymer mother solution may comprise one or more additional components, for example, but not limited to a surfactant, biocide, alkaline component such as, but not limited to caustic soda, antifoaming agent, or a combination thereof. In the event that a surfactant or other component is employed in the polymer mother solution, it preferably comprises an amount between about 20 parts per million (ppm) and about 5000 ppm, preferably about 500 ppm and about 5000 ppm, for example, but not limited to 20, 50, 100, 200, 500, 1000, 2000, 2500, 3000, 4000, 5000 or any amount therein between. Further, the surfactant may be defined by a range of any two of the values listed above or any amount therein between. Without wishing to be bound by theory or limiting in any manner, a surfactant may lower the interfacial tension of oil deposits and facilitate extraction from subterranean formations.

By the term “polymer daughter solution” it is meant an aqueous solution comprising the polymer mother solution, water and optionally one or more additional components. Typically, the polymer daughter solution comprises a polymer concentration that is about the same or less than the polymer mother solution. As such, the polymer daughter solution usually comprises a lower viscosity than the polymer mother solution.

It is also to be understood that the polymer daughter solution may comprise one or more additional components not found in the polymer mother solution. Similarly, the polymer daughter solution may comprise one or more additional components in a different concentration as compared to the polymer mother solution. By way of example, but not to be considered limiting in any manner, the polymer mother solution may be prepared using a potable water source having low salinity. Prior to being injected into a well, the polymer mother solution may be diluted with water from a saline well having high salinity. Accordingly, it is apparent that the polymer daughter solution may comprise higher levels of dissolved salts, and potentially other components as compared to the polymer mother solution. In still a further embodiment, which is not meant to be considered limiting in any manner, the polymer daughter solution may comprise an added surfactant not present in the polymer mother solution. Other potential differences between the polymer mother solution and the polymer daughter solution will be evident to a person of skill in the art having regard to the disclosure as provided herein.

In an embodiment which is not meant to be limiting in any manner, the polymer daughter solution is polymer mother solution diluted with water. In a specific embodiment, but not wishing to be considered limiting in any manner, the polymer daughter solution comprises polyacrylamide solution of between about 500 ppm and about 2000 ppm, more preferably about 1000 to about 1500 ppm. However, a polymer daughter solution outside this range is also contemplated.

In the embodiments described herein, it is preferred that polymer mother solution is sufficiently hydrolysed prior to being diluted to form polymer daughter solution and before injection into a well. For example, but not wishing to be limiting, the polymer mother solution may remain in a vessel, holding tank, pipeline or network of pipes for at least a specified duration in order for the polymer to hydrolyse to a desired viscosity. Further, it is contemplated that the extent of hydrolysis and/or the viscosity of the solution may be measured and/or monitored at one or more points within the polymer transport system including for example, but not limited to the vessel, holding tank, pipeline, network of pipes, or injection pod polymer mother solution feed line by any method known in the art. Without wishing to be limiting or bound by theory in any manner, it is possible that some polymers may require time to fully hydrate, unravel and expand to create a viscous solution.

The polymer mother solution may be provided as a premade solution or alternatively, the polymer mother solution may be prepared on site, for example, but not limited to, by mixing together dry polymer, water and optionally one or more additional components. Accordingly, the polymer transport and distribution system may comprise a dry polymer holding vessel or container, a dry polymer transfer system, a water inlet source, an input source for optionally adding one or more additional components to the dry polymer, water or polymer mother solution, a mixer for preparing the polymer mother solution, a polymer mother solution transport system, for example, but not limited to one or more pumps, a vessel or container for holding polymer mother solution, one or more pipelines or network of pipes or any combination thereof. Several or all of these components may be contained in a polymer processing station (polymer pod) which may be or may not be located remotely from the injection pod sites and wells.

The water inlet source providing water for mixing with polymer may be provided from a well, for example, but not limited to a freshwater or saline well, water pipeline, water filtration skid or the like. It is also contemplated that the water inlet source may be connected to a water pipeline or network of water pipes that extends over the oil/gas field being tapped. In an embodiment, the water is substantially pure meaning that it comprises a low amount, for example between 1500 to about 2500 ppm, or lower of total dissolved solids as described herein, particularly salts as high levels of salts and are known to inhibit hydrolysis and/or promote breakdown of hydrolysed polymers such as polyacrylamides. However, water from a saline well also may be employed, and may be preferred in instances wherein the polymer is resistant to viscosity breakdown in the presence of dissolved salts.

Dry polymer may be fed into a mixer by a dry polymer transfer system which may comprise without limitation, a calibrated auger or the like. In a preferred embodiment, the dry polymer transfer system comprises a Hapman helix conveyor. Alternatively, the dry polymer may be transferred by an air transfer system or both an air transfer system and a conveyor. Any such system as would be known in the art may be employed in the polymer transport and distribution system. Further, one or more optional components may be added likewise or they may be added using other methods and/or apparatuses known in the art.

The mixing of dry polymer, water and optionally any additional components may be performed in any vessel, holding tank or pipeline by a suitable mixer or mixing device. In a preferred embodiment, the mixer or mixing device is a Model 1700 Comitrol Processor made by Urschel Labs. Such a device has been shown to decrease the time necessary to prepare viscous polymer mother solution. While such devices are preferred, other mixing devices can be employed in the present invention. As will be evident to a person of skill in the art, it is preferred that polymer powder is thoroughly mixed with water and attains the desired viscosity prior to being diluted to form polymer daughter solution or injected into a well. In this manner, polymer mother solution may be prepared and retained in a vessel or holding tank until the polymer mother solution exhibits a desired viscosity. Alternatively, polymer mother solution may be prepared and transported in a pipeline or network of pipes to a second remote location. In such an embodiment, it is preferred that the polymer mother solution attain the desired viscosity while being pumped through the pipeline or network of pipes before being diluted to form polymer daughter solution or injected into a well.

The embodiment described above contemplates that that the vessel containing the polymer mother solution or the polymer processing station that prepares the polymer mother solution can be located remotely from the injection pod or well sites, for example, but not limited to about 1, 2, 5, 6, 10 or more km therefrom. Thus, polymer mother solution may be prepared and/or stored in a separate area, building, or facility from that of the injection pods wherein the daughter polymer solution is injected into a well. Polymer mother solution can be pumped from this remote site through a pipeline or network of pipes to the injection pod sites wherein the polymer mother solution is diluted with water and optionally formulated with other components to obtain a daughter polymer solution having a desired viscosity and/or one or more desired chemical characteristics for injection into a well. Further, but without wishing to be limiting in any manner, the water used for mixing with polymer mother solution may be provided via a vessel, pipeline or network of pipes that parallels or intersects that providing the polymer mother solution at one or more points. In an embodiment of the present invention, the polymer transport and distribution system comprises a plurality of injection pod sites, for example, two, three, four, five or more injection pod sites. In a preferred embodiment, the polymer transport and distribution system comprises five or less sites. Similarly, in an embodiment of the present invention, the polymer transport and distribution system comprises a plurality of injection wells within each injection pod site, for example two, three, four or more injection wells. In a preferred embodiment the polymer distribution and transport system comprises four injection wells within each injection pod site.

Referring now to FIG. 1, there is shown a representative non-limiting embodiment of the present invention. Polymer processing station (polymer pod (10)) receives water from a freshwater source (20) to produce polymer mother solution which is pumped through polymer mother solution pipeline network (30) to a plurality of injection pods or injection well sites (40). Each injection well site (40) comprises a polymer mother solution feed line (50), a water input feed line (60) providing high pressure dilution water from water pipeline network (35) and at least a second pump for controlling mother solution flow rate and pressure upstream of the water input feed line used for producing and injecting polymer daughter solution into an oil or gas field well (70). Also shown are producer wells (80) for extracting oil and gas from subterranean formations in an oil or gas field (100).

In an alternate embodiment of the present invention which is not meant to be limiting in any manner, the polymer transport and distribution system comprises,

    • a dry polymer transfer system, a water inlet source, and a first mixer for preparing a polymer mother solution from dry polymer and water, the resulting polymer mother solution contained in a vessel;
    • one or more pumps for transporting polymer mother solution through a pipeline or network of pipes to one or more remote injection pod sites, each injection pod site comprising,
    • one or more injection wells, each injection well comprising a polymer mother solution input feed line, a high pressure water input feed line, a second mixer to produce polymer daughter solution and a pump for controlling mother solution flow rate and pressure upstream of a high pressure dilution water input feed line, for injecting the resulting polymer daughter solution into a well.

The present invention also provides a method of distributing polymer to one or more injection well sites in an oil or gas field comprising,

    • a) providing a polymer mother solution;
    • b) pumping the polymer mother solution through a pipeline or network of pipes from a first location to one or more remote locations comprising at least one injection pod or well site;
    • c) mixing the polymer mother solution with water and optionally one or more additional components to form a polymer daughter solution and;
    • d) injecting the polymer daughter solution into a well.

In a further embodiment of the present invention there is provided a method of distributing polymer to one or more injection well sites in an oil or gas field comprising,

    • a) storing or producing a polymer mother solution in a polymer processing station;
    • b) pumping the polymer mother solution through a pipeline or network of pipes from the polymer processing station to one or more remote injection pod or well sites;
    • c) mixing the polymer mother solution with water and optionally one or more additional components to form a polymer daughter solution and;
    • d) injecting the polymer daughter solution into a well.

In an alternate embodiment of the present invention, there is provided a method of distributing polymer to one or more injection well sites in an oil or gas field comprising,

    • a) storing or producing a polymer mother solution in a polymer processing station;
    • b) pumping the polymer mother solution through a pipeline or network of pipes from the polymer processing station to one or more remote injection pods or injection well sites;
    • c) mixing the polymer mother solution with water and optionally one or more additional components at the injection pod or injection well contained therein to form a primary polymer daughter solution and;
    • d) injecting the primary polymer daughter solution into the injection well;
    • e) extracting oil from a producer well in fluid communication with the injection well, and;
    • f) optionally, mixing polymer mother solution with water and if desired, one or more additional components at the injection pod or injection well site contained therein to form a secondary polymer daughter solution, wherein the secondary polymer daughter solution is more dilute in polymer concentration and less viscous than the primary daughter solution,
    • g) injecting the secondary daughter polymer solution into the injection well;
    • h) extracting oil from the producer well in fluid communication with the injection well, and;
    • i) optionally repeating steps f)-h) using successively more dilute and less viscous daughter solutions.

EXAMPLES

In a preferred embodiment of the present invention, polymer is brought onto a skid in 750 kg bags via an overhead crane. The bags of dry polymer are hoisted over top and unloaded into a hopper. From the hopper, the polymer is transferred, for example via a Hapman helix conveyor/auger to a storage silo. From storage silo, polymer powder is augured into a mixer, for example, but not limited to an Urschel mixer or the like. Water is filtered through a standard bag filter and then fed into the mixer at the same time in controlled proportions to created the required polymer mother solution. Typically, but not always, the polymer mother solution comprises from about 5000 to 15000 ppm depending on particular well injection requirements. The polymer mother solution falls out of the bottom of the urschel mixer and is then transferred to a tank via a lobe pump where it undergoes hydrolysis prior to being diluted to form polymer daughter solution.

Once the polymer mother solution has sufficiently hydrolysed, it is pumped through a pipeline or pipeline network to the injection pod or injection well sites. This is accomplished by a progressive cavity pump which draws the polymer off the bottom of the tank and pressurizes it up to the pressure required to transport the polymer to distant/remote injection pod or well sites. In this example, but not to be considered limiting in any manner, the pipeline feeds up to 5 injection pods which are up to about 1.6 km away from the polymer processing station. Each injection pod comprises a separate pump for each well wherein polymer is injected. The pod sites are laid out with 4 injection wells per pod. There is one injection skid per pod which has four pumps in it to feed the wells. Polymer mother solution is metered as it goes out the building, and then it is blended with water to create polymer daughter solution having the required polymer concentration before being injected down the wells. Typical polymer concentrations of polymer daughter solution injected down each well are about 1000 to about 1500 ppm thus requiring roughly a 9:1 blend of water to polymer mother solution.

All citations are hereby incorporated by reference.

The present invention has been described with regard to one or more embodiments. However, it will be apparent to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as defined in the claims.