Patent Application
20210230979
The present description relates to a nozzles, or flow control device, used for controlling flow of fluids into a tubular member, such as during the production phase of a hydrocarbon extraction process. In a particular aspect, the nozzle is adapted for use on tubular members used for producing hydrocarbons from subterranean reservoirs. More particularly, the described nozzle aids in retaining solvents used for production in a liquid state.
Subterranean hydrocarbon reservoirs are generally accessed by one or more wells that are drilled into the reservoir to access the hydrocarbon materials. Such materials (which may be referred to simply “hydrocarbons”) are then pumped to the surface through production tubing. The wells drilled into the reservoirs may be vertical or horizontal or at any angle there-between.
In conventional hydrocarbon production methods, the wells are drilled into a hydrocarbon containing reservoir and the hydrocarbon materials are brought to surface using, for example, pumps etc. In some cases, such as where the hydrocarbons comprise a highly viscous material, such as heavy oil and the like, enhanced oil recovery, or “stimulation”, methods may be used. Steam Assisted Gravity Drainage, “SAGD” and Cyclic Steam Stimulation, “CSS”, are examples of these methods. Such methods serve to increase the mobility of the desired hydrocarbons and thereby facilitate the production thereof. In a SAGD operation, a number of well pairs, each typically comprising a horizontal well, are drilled into a reservoir. Each of the well pairs comprises a steam injection well and a production well, with the steam injection well being positioned generally vertically above the production well. In operation, steam is injected into the injection well and the heat from such steam is allowed to permeate into the surrounding formation and thereby reduce the viscosity of hydrocarbon material, typically heavy oil, in the vicinity of the injection well. After steam treatment, the hydrocarbon material, now mobilized, drains into the lower production well by gravity, and is subsequently brought to the surface through the production tubing. In a CSS process, a single well may be used to first inject steam into the reservoir through tubing, generally production tubing. After the steam injection stage, the heat from the steam is allowed to be absorbed into the reservoir, a stage referred to as “shut in” or “soaking”, during which the viscosity of the neighbouring hydrocarbon material is reduced thereby rendering such material more mobile. Following the shut in stage, the hydrocarbons are produced through the well in a production stage.
Tubing used in wellbores typically comprises a number of segments, or tubulars, that are connected together. Various tools (such as packers, sleeves, downhole telemetry devices etc.) may also be provided at one or more positions along the length of the tubing and connected inline with adjacent tubulars. The tubing, for either steam injection and/or hydrocarbon production, generally includes a number of apertures, or ports, along its length. The ports provide a means for injection of steam and/or other viscosity reducing agents, and/or for the inflow of hydrocarbon materials from the reservoir into the pipe and thus into the production tubing. The segments of tubing having ports are also often provided with one or more filtering devices, such as sand screens, which serve to prevent or mitigate against sand and other solid debris in the well from entering the tubing.
It is also common to incorporate nozzles, or flow control devices, for controlling the flow of fluids into (e.g. for production) or out of (e.g. for steam injection etc.) the ports. For example, inflow control devices, or ICDs, are provided in combination with sand screens and are positioned adjacent ports on the tubing. In this way, the ICDs control the flow of fluids entering the tubing after being filtered to remove particles and other debris. Various ICDs have been proposed for the purpose of limiting or choking the flow of steam and/or non-condensable gas (NCG). In such cases, the ICDs are provided with internal profiles specifically designed for the given purpose (e.g. steam or NCG choking, etc.) Examples of known ICDs designed for restricting undesired production of NCG and like components are provided in US 2017/0044868; U.S. Pat. No. 7,537,056; US 2008/0041588; and, U.S. Pat. No. 8,474,535. Many of these ICDs involve the use of moving elements to dynamically adjust to local fluid compositions and are therefore relatively complicated. Other ICDs are primarily concerned with choking of gas contained in the reservoir, so as to preferentially produce heavier hydrocarbon components. An example of such nozzle is provided in the Applicant's PCT Application No. PCT/CA2019/051407, the entire contents of which are incorporated herein by reference.
In addition to, and/or in combination with, the hydrocarbon production methods as discussed above, e.g. SAGD, CSS, it is also common to improve the production of heavy hydrocarbon materials (generally referred to herein as “oil”) by injecting one or more solvents into the reservoir to increase the mobility of the desired materials. These methods are often referred to as solvent-assisted or solvent-based recovery methods. The solvents typically comprise light, or low molecular weight hydrocarbon materials, such as for example C3 to C12 hydrocarbons. These solvents are injected into the reservoir, often in combination with steam (such as for SAGD or CSS), and are allowed to mix with the heavy oil in the reservoir. The resulting decrease in viscosity of the mixture improves flowability of the oil and therefore improves production efficiency.
When using solvents, one problem that is encountered is the flashing of the liquid solvent during the production phase. More specifically, within the reservoir, which is at a higher pressure, the injected solvent is present in liquid form; however, during production, as the solvent passes through the ports in the production tubing, the pressure drop across the port, or, if present the nozzle, results in flashing of the liquid solvent into its vapour form. This has two consequences. First, due to its higher mobility, the solvent vapour is preferentially produced over the desired oil, thereby reducing production efficiency. Second, once flashed, recovery of the solvent component is difficult, thereby resulting increased solvent cost.
There exists a need for an improved nozzle, or ICD, that prevents the flashing of solvent during production of oil from a reservoir.
In one aspect, there is provided an inflow control nozzle for maintaining solvent in liquid form during production of hydrocarbons into a pipe, the pipe having at least one port along its length, the nozzle being adapted to be located on the exterior of the pipe and adjacent one of the at least one port, the nozzle comprising first and second openings and a fluid passage extending there-between, and wherein the fluid passage includes converging and diverging sections.
In one aspect, there is provided an inflow control nozzle for maintaining solvent in liquid form during production of hydrocarbons into a pipe, the pipe having at least one port along its length, the nozzle being adapted to be located on the exterior of the pipe and adjacent one of the at least one port, the nozzle comprising:
In one aspect, the throat of the nozzle is located closer to the inlet.
In another aspect, there is provided an apparatus for maintaining solvent in liquid form during production of hydrocarbons into a pipe, the apparatus comprising: a pipe segment having at least one port along its length; at least one inflow control nozzle located on the exterior of the pipe and adjacent one of the at least one port; and, a means for locating the nozzle on the pipe adjacent the port; wherein the nozzle comprises:
In another aspect, there is provided a method of producing fluids from a subterranean reservoir while limiting the flashing of at least one solvent present in the reservoir, the method comprising:
The features of certain embodiments will become more apparent in the following detailed description in which reference is made to the appended figures wherein:
It will be understood that
As used herein, the terms “nozzle”, “nozzle insert”, or “flow control device” will be understood to mean a device that controls the flow of a fluid flowing there-through. In one example, the nozzle described herein serves to control the flow of a fluid through a port in a pipe in at least one direction. More particularly, the nozzle described herein comprises an inflow control device, or ICD, for controlling the flow of fluids into a pipe through a port provided on the pipe wall.
The terms “regulate”, “limit”, “throttle”, and “choke” may be used herein. It will be understood that these terms are intended to describe an adjustment of the flow of a fluid passing through the nozzle described herein. The present nozzle is designed to allow the flow of a volatile material, such as a solvent for heavy oil recovery, while avoiding or limiting the degree to which solve volatile material is flashed as it passes through the nozzle.
The term “hydrocarbons” refers to hydrocarbon compounds that are found in subterranean reservoirs. Examples of hydrocarbons include oil and gas. For the purposes of the present description, the desired hydrocarbon component is primarily oil, such as heavy oil.
The term “solvent” refers to solvents that injected into hydrocarbon-containing reservoirs to improve the production of such hydrocarbons. The solvent for the present description may be any solvent known in the art for hydrocarbon recovery. Typically, such solvents are light hydrocarbon materials, comprising, for example, one or more C3 to C12 compounds.
The term “wellbore” refers to a bore drilled into a subterranean formation, such as a formation containing hydrocarbons.
The term “wellbore fluids” refers to hydrocarbons and other materials contained in a reservoir that are capable of entering into a wellbore. The present description is not limited to any particular wellbore fluid(s).
The terms “pipe” or “base pipe” refer to a section of pipe, or other such tubular member. The base pipe is generally provided with one or more ports or slots along its length to allow for flow of fluids there-through.
The term “production” refers to the process of producing wellbore fluids, in particular, the process of conveying wellbore fluids from a reservoir to the surface.
The term “production tubing” refers to a series of pipe segments, or tubulars, connected together and extending through a wellbore from the surface into the reservoir.
The terms “screen”, “sand screen”, “wire screen”, or “wire-wrap screen”, as used herein, refer to known filtering or screening devices that are used to inhibit or prevent sand or other solid material from the reservoir from flowing into the pipe. Such screens may include wire wrap screens, precision punched screens, premium screens or any other screen that is provided on a base pipe to filter fluids and create an annular flow channel. The present description is not limited to any particular screen described herein.
The terms “comprise”, “comprises”, “comprised” or “comprising” may be used in the present description. As used herein (including the specification and/or the claims), these terms are to be interpreted as specifying the presence of the stated features, integers, steps or components, but not as precluding the presence of one or more other features, integers, steps, components or a group thereof, as would be apparent to persons skilled in the relevant art.
In the present description, the terms “top”, “bottom”, “front” and “rear” may be used. It will be understood that the use of such terms is purely for the purpose of facilitating the description of the embodiments described herein. These terms are not intended to limit the orientation or placement of the described elements or structures in any way.
Another nozzle, or inflow control device, ICD, is illustrated in
The present inventor has found that the nozzles shown in
In general, the present description relates to a flow control device, or nozzle, that serves to control or regulate the flow of fluids between a reservoir and a base pipe, or section of production tubing. As discussed above, one of the problems encountered in solvent-assisted oil recovery operations is that the injected solvent component is often flashed as it enters the production tubing (i.e. as it passes through the port or a nozzle provided therewith). Therefore, in one aspect, the presently described nozzle prevents or at least mitigates against such flashing by means of a unique internal passage profile that avoids large pressure drops as the solvent passes there-through.
For this purpose, the nozzle described herein comprises an inlet and an outlet and a flow path, or passage, there-between, the converging portion includes a constriction, comprising a region of the passage having the smallest cross-sectional area. The nozzle may also include a third section comprising a region of constant cross-sectional area proximal to the outlet.
One aspect of the nozzle of the present description is illustrated in
In one aspect, as illustrated in
The inlet 12 and outlet 14 of the nozzle 10 may have the same or different diameters.
As shown in
As shown in
It will be understood that the nozzle 10 may be positioned over the pipe 100 in any number of ways. For example, in one aspect, the outer surface of the pipe 100 may be provided with a slot into which the nozzle 10 may be located. The nozzle 10 may be welded or otherwise affixed to the pipe 100 or retained in place with the retaining device 106 as discussed above.
In assembling the apparatus incorporating a sand screen, the pipe 100 is provided with the nozzle 10 and the screen 104 and the associated retaining device 106. The pipe 100 is then inserted into a wellbore.
During the production stage, wellbore fluids, also referred to as production fluid, as illustrated by arrows 108, pass through the screen 104 (if present) and are diverted to the nozzle 10. The production fluid enters the first opening or inlet 12 of the nozzle 10 and flows through the passage 16 as described above, finally exiting through the second opening or outlet 14, to subsequently enter into the port 102 and, thereby, into the lumen 103 of the pipe 100. The fluid is then brought to the surface using commonly known methods.
As would be understood by persons skilled in the art, the nozzles described herein are designed, in particular, to be included as part of an apparatus associated with tubing, an example of which is illustrated in
The examples provided herein serve to illustrate the advantages of the present nozzle over those illustrated in
{dot over (m)}=C
d
×A×√{square root over (2ΔPρ)}
In this equation, {dot over (m)} is mass flow rate, Cd is the discharge coefficient, A is the open flow area, ΔP is pressure drop, and ρ is the density of the fluid. In the situation where solvent is flashed, the average density of the flowing fluid over the entire nozzle volume will be lowered. Since the discharge coefficient, Cd, the throat size (i.e. open flow area, A) and pressure differential, ΔP, between inlet and outlet of the nozzle are generally constant, it will be understood that a reduction in density would result in a corresponding reduction in the mass flow rate of the liquid solvent.
In contrast,
As discussed above, although the nozzle shown in
The following example summarizes a simulation that was conducted to illustrate the performance characteristics of the nozzle described herein. It will be understood that this example is only intended to illustrate the advantages of the nozzle described herein and is not intended to limit the scope of the description in any way.
In this example, the performance characteristics of the nozzles illustrated in
Table 1 summarizes the dimensions of the nozzles used for the simulation.
As indicated above, the nozzles tested were of different lengths. Although the lengths of the nozzles of
The results from the simulations of the nozzles of
As shown in
The results of this example clearly show that the gradual or mild converging and diverging regions provided in the nozzle described herein meet the desired need of mitigating against solvent flashing in a solvent-assisting oil recovery operation.
Although the above description includes reference to certain specific embodiments, various modifications thereof will be apparent to those skilled in the art. Any examples provided herein are included solely for the purpose of illustration and are not intended to be limiting in any way. In particular, any specific dimensions or quantities referred to in the present description is intended only to illustrate one or more specific aspects are not intended to limit the description in any way. Any drawings provided herein are solely for the purpose of illustrating various aspects of the description and are not intended to be drawn to scale or to be limiting in any way. The scope of the claims appended hereto should not be limited by the preferred embodiments set forth in the above description but should be given the broadest interpretation consistent with the present specification as a whole. The disclosures of all prior art recited herein are incorporated herein by reference in their entirety.
The present application claims priority under 35 U.S.C. 119 to U.S. Application No. 62/965,588, filed Jan. 24, 2020, the entire contents of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62965588 | Jan 2020 | US |
