Automatic water control device based on fluid density difference

Abstract

The present invention discloses an automatic water control device based on fluid density differences, which mainly solves the problem of how to successfully control water and increase oil production in oil reservoirs with similar formation fluid viscosities in the prior art. The device includes a shell and a baffle, a fluid selector sealed inside the shell and the baffle, a production valve and a pressure relief one-way valve, and a collection channel for the final fluid to flow into. Through the above scheme, the present invention achieves the purpose of using formation fluid to drive the fluid selector to rotate, thereby opening the production valve in oil and closing it in water, achieving a density-based water control and oil production increase effect, and has high practical and promotional value.

Description

Technical Field

[0001] The present invention relates to the field of water control technology, and in particular to an automatic water control device based on fluid density differences. Background Art

[0002] Horizontal well production has been one of the most prioritized oil and gas reservoir production technologies in recent years and has been widely used in the development of various reservoir types. With the promotion and application of horizontal well technology, some problems that cannot be ignored have gradually emerged. Due to the heterogeneity of permeability at different locations in the formation and the pressure drop along the wellbore flow direction, the inflow profile of the horizontal wellbore is uneven, which can easily lead to pressure drop funnels, premature water or gas breakthrough, and a sharp drop in production. Such problems often seriously affect the oil production and economic benefits of the oil well. In severe cases, they can even lead to violent flooding of the horizontal well, forcing the well to be shut down and causing significant losses.

[0003] To balance fluid flow along the horizontal wellbore and delay water inrush, new water control completion methods for horizontal wells have been widely used in recent years, including: ICD (Inflow Control Device) water control completion, continuous packer ICD water control completion, and AICD (Automatic Inflow Control Device) water control completion. The pressure drop generated by the ICD water control valve is designed and determined before installation, and its water control strength cannot be changed after installation unless the well is re-completed. Continuous packer ICD water control refers to the reduction or elimination of annular flow and its adverse effects on completion performance by running a continuous packer on top of the ICD water control completion. The AICD water control valve can automatically adjust the additional pressure drop it generates based on the downhole fluid conditions, and can achieve water control by providing a larger additional pressure drop for low-viscosity fluids.

[0004] Current domestic patents for AICDs primarily rely on the principle that high-viscosity oil takes fewer paths in the AICD, while low-viscosity water takes more paths, to achieve the desired effect of water control and oil production increase. Chinese Patent Application No. 201610946014.1, a design method for AICD flow path parameters, and Chinese Patent Application No. 201811080478.4, an AICD water control device, both address the separation of oil and water when there is a viscosity difference. However, they fail to consider the issue of high water production in the later stages of an oil well, which can obscure the viscosity difference. Furthermore, existing AICDs experience significant pressure drops under the influence of high-velocity fluids in the formation. As oil wells produce, the initial reservoir saturation decreases, while water saturation is relatively high, making water near the bottom of the well more easily produced. AICD water control valves based on fluid viscosity do not perform well. Therefore, there is an urgent need for a new AICD that does not rely on fluid viscosity differences and can function properly even with low fluid pressure drops. Summary of the Invention

[0005] Based on the aforementioned defects of the prior art in that the viscosity difference between oil and water in oil and gas wells is small in the later stage and AICD cannot perform separation well, an embodiment of the present invention provides an automatic water control device based on fluid density selection, which can generate a pressure drop according to the density difference between oil and water, promote the separation of oil and water, and achieve better oil increase and water control effects.

[0006] In order to achieve the above objectives, the present invention provides the following technical solutions.

[0007] An automatic water control device based on fluid density differences includes a housing, a fluid selector, a production valve, a pressure relief check valve, and a collection channel. While oil-water separation is used as an example to illustrate the device's functionality, the device is not limited to oil-water separation and is applicable to the separation of any fluid with a density difference.

[0008] An embodiment of an automatic water control device based on fluid density difference is proposed. The shell has a nozzle for fluid to enter the device, and the interior of the shell is divided into three chambers. The first chamber has a boss, and the interior of the boss can be connected to a fluid selector by means of a thread. The first chamber has a side flow channel connected to the second chamber; the second chamber of the production valve is fixed by a bolt connection, and the production valve outlet at the bottom is connected to the collection channel. The second chamber and the third chamber are connected by a central flow channel; the third chamber of the pressure relief one-way valve is fixed by means of a thread or the like, and is connected to the collection channel through the one-way valve outlet at the bottom.

[0009] Furthermore, an embodiment of a fluid selector is proposed. The fluid rotator can rotate radially about an intermediate axis. The incoming fluid drives the impeller to rotate, generating centripetal acceleration through rotation. This centripetal acceleration can easily reach more than 30 times the acceleration due to gravity g, making the influence of gravity on the float negligible.

[0010] Furthermore, the density of the float is between that of oil and water, and multiple floats can be set in stages according to the effective density to achieve precise control of the fluid entering the intermediate shaft.

[0011] Furthermore, the float moves away from the middle axis in a fluid with a lower density than itself, and moves toward the middle axis in a fluid with a higher density than itself. The number of float channels opened varies as the float approaches or moves away from the middle axis, thereby obtaining the required effective density of fluid as much as possible.

[0012] Furthermore, an intermediate manifold is connected above the intermediate shaft, and the fluid entering the interior of the intermediate shaft is flown into the bottom of the subsequent production valve according to the opening condition of the float channel.

[0013] Furthermore, a flow channel is reserved in the production valve for connecting to the intermediate manifold. The production valve is a valve that is kept in a normally closed state by a spring. The valve and the collection channel collect the fluid of the required density by opening and closing the valve.

[0014] Furthermore, when the fluid is of the required effective density, such as oil, the float moves away from the intermediate shaft, closing the float channel. No fluid passes through the intermediate manifold, and no fluid flows into the bottom of the production valve from the intermediate manifold. A pressure difference is generated at the upper and lower ends of the production valve, compressing the production valve spring, causing the valve to open and the fluid to flow into the collection channel.

[0015] Furthermore, when the fluid is an unnecessary fluid with a non-effective density, such as water, the float moves toward the middle axis, the float channel opens, and fluid passes through the middle manifold. The bottom of the production valve receives the fluid flowing in from the middle manifold. The pressure difference between the upper and lower ends of the production valve is small, the production valve spring is not compressed, the valve remains closed, and the fluid does not flow into the collection pipe.

[0016] Furthermore, the fluid that is not collected into the collection pipeline flows through the central pipeline to the third-stage pressure relief one-way valve. The opening of the one-way valve is much smaller than the opening when the production valve is opened. A small amount of fluid flows into the collection channel through the one-way valve, ensuring that the entire device has a pressure relief port when the production valve is closed, maintaining normal operation and preparing for the subsequent opening of the production valve.

[0017] In addition to the float, the fluid selector used to achieve fluid density differentiation in the present method can also adopt any existing shape that can be thought of by those skilled in the art, such as a square float block, an irregular float block, etc.

[0018] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0019] 1. The present invention drives the fluid selector to rotate by fluid impacting the impeller bearing, allowing the float to move inside the channel by relying on centripetal force and different fluid densities, controlling the opening and closing of the production valve, so that the required fluid enters the collection channel, and the unnecessary fluid enters the collection channel slowly or in small quantities, filling the gap in existing AICD technology.

[0020] 2. The fluid selector of the present invention can accurately control the collected fluid according to the multi-level setting of the fluid density. It is suitable for fields such as downhole fluid density differences and difficulty in water-gas separation, and has strong applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0022] Figure 1 A schematic diagram of a specific embodiment of the present invention;

[0023] Figure 2 A half-section structural diagram of a specific embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the housing structure of a specific embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the flow channel structure of the first cavity of the shell according to a specific embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of the structure of a fluid selector in a specific embodiment of the present invention;

[0027] Figure 6 This is a structural diagram of a production valve in a closed state in a specific embodiment of the present invention;

[0028] Figure 7 This is a structural diagram of a production valve in an open state in a specific embodiment of the present invention;

[0029] In the above drawings, the component names corresponding to the reference numerals are as follows:

[0030] 1-housing, 2-baffle, 3-fluid selector, 4-intermediate manifold, 5-production valve, 6-pressure relief check valve, 7-collecting channel, 11-nozzle, 12-first cavity, 13-boss, 14-side flow channel, 15-second cavity, 16-central flow channel, 17-third cavity, 31-impeller, 32-float channel, 33-intermediate shaft, 34-bearing, 35-float, 51-production valve seat, 52-production valve disc, 53-production valve spring. DETAILED DESCRIPTION

[0031] The present invention will be further described below with reference to the accompanying drawings and examples. The embodiments of the present invention include but are not limited to the following examples.

[0032] Example

[0033] like Figures 1 to 5As shown, the automatic water control device based on fluid density difference includes the entire device shell 1 and the nozzle 11 inside for receiving the formation fluid screened by the front sand control pipe and other mechanisms. The device has three chambers inside and a baffle 2 for sealing the inner part of the shell 1; the first chamber 12 near the nozzle contains a fluid selector 3, which includes a boss 13 base fixed to the shell 1, an intermediate shaft 33 with an internal flow channel connected to the base by a connection method such as a thread, a rotatable bearing 34 and an impeller 31 fixed to the intermediate shaft 33, and a float channel 32 and a density-variable float inside the intermediate shaft 33. Sub 35; the second cavity 15 contains the production valve 5, including a production valve body 51 fixed to the shell 1 by screws or the like, and the opening and closing of the fluid entering the collection channel 7 are controlled by a spring 53 and a production valve disc 52 inside; the fluid selector 3 and the production valve 5 are connected by an intermediate manifold 4, and the third cavity 17 contains a pressure relief one-way valve 6, which is mainly used to relieve pressure on the entire device when the production valve 5 is closed to ensure that the device can work normally. The fluid flow rate of the pressure relief one-way valve 6 into the collection channel 7 is much smaller than the flow rate of the fluid into the collection channel 7 when the production valve 5 is open.

[0034] The following uses oil and water as an example to explain the working principle of the entire device: When the proportion of water in the formation fluid is relatively large, the fluid enters through the nozzle and drives the fluid selector impeller to rotate under the action of the bearing. Since the water density is greater than the density set by the float, the float moves toward the direction of the intermediate shaft, opening the float channel. The fluid flows through the channel through the intermediate manifold to the bottom of the production valve. Since there is fluid above and below the production valve disc, the force above the valve disc (external fluid pressure) and the force below the valve disc (internal fluid pressure and spring force) are balanced, which is not enough to compress the production valve spring, resulting in the fluid being unable to pass through the production valve into the collection channel. Therefore, the fluid inside the production valve continues to flow through the central pipeline to the next-level one-way valve, and a small amount is merged into the collection channel, so that there is a pressure relief port in this case, which will not cause the production valve to be pressurized, thereby ensuring that the entire mechanism can continue to work normally.

[0035] When the formation fluid contains a large proportion of oil, fluid enters through the nozzle and, driven by the bearing, drives the fluid selector impeller to rotate. Because the oil density is lower than the float's set density, the float moves away from the intermediate shaft, closing the float channel. Fluid cannot pass through this channel and flow through the intermediate manifold to the bottom of the production valve. The force above the production valve disc (external fluid pressure) is much greater than the force below (spring force alone), creating a large pressure differential that compresses the production valve spring, opening the production valve and allowing a large amount of fluid to flow into the collection channel. This principle achieves the goal of controlling water and increasing oil production.

[0036] It's worth noting that the float density can be set in multiple levels, ranging from oil to water, to accommodate situations where the formation fluid also varies between oil and water. When the float is in fluids of varying densities, one, two, or more float channels are opened or closed, resulting in varying fluid flow pressures entering the production valve. This, in turn, affects the forces above and below the production valve disc, leading to varying valve openings and, consequently, varying fluid collection flow rates. The diameter of the intermediate manifold is generally larger than that of the central manifold to ensure that when the formation fluid density is high, the interior of the production valve remains filled with fluid, allowing the valve to remain closed.

[0037] Using the above example of oil-water separation, the present invention's automatic water control device based on fluid density differences can open a valve to collect fluid when the fluid has the density required by the producer; and close the valve or open it very slightly when the fluid has an undesirable density, preventing or minimizing fluid collection. This allows the automatic selection of the fluid required by the producer based on different fluid densities.

[0038] In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention. In the description of this application, it should be understood that the orientations or positional relationships indicated by terms such as "front", "back", "left", "right", "up", "down", "inside", and "outside" are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of this application.

[0039] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any changes that adopt the design principles of the present invention and any changes made through non-creative work on this basis should fall within the scope of protection of the present invention.

Claims

1. Automatic water control device based on fluid density difference, characterized in that: The device comprises a shell (1), a baffle (2), a fluid selector (3), an intermediate manifold (4), a production valve (5), a pressure relief check valve (6) and a collection channel (7). The baffle (2) for sealing the internal device is fixed to the upper part of the shell (1) by bolts. The shell (1) has three chambers inside. The fluid selector (3) is fixed to the first chamber (12) by threads. The production valve (5) is fixed to the inside of the second chamber (15) by bolts. The intermediate manifold (4) communicates the upper end of the fluid selector (3) and the bottom of the production valve (5). The pressure relief one-way valve (6) is fixed to the inside of the third cavity (17) by means of a thread, and the production valve (5) and the collecting channel (7) connected to the bottom of the pressure relief one-way valve (6) are used to collect fluid; the shell (1) has a nozzle (11) for the fluid inlet device, and the inside of the shell is divided into three cavities, the first cavity (12) has a boss (13), the inside of which is connected to the fluid selector (3) by means of a thread, and the first cavity (12) has a side flow channel (14) connected to the second cavity (15); fixed by bolt connection The second cavity (15) of the production valve (5) is connected to the collecting channel (7) at the bottom, and the production valve (5) and the third cavity (17) are connected via a central flow channel (16); the third cavity (17) of the pressure relief check valve (6) is fixed by a thread, and the bottom is connected to the collecting channel (7); the fluid selector (3) is composed of an impeller (31), a float channel (32), an intermediate shaft (33) with an internal flow channel, a bearing (34), a float (35), a housing (1), and an intermediate manifold (4) connected to the production valve (5). The impeller (31) and the bearing (34) are mounted on an intermediate shaft (33) having an internal flow channel, so that the fluid drives the impeller (31) to rotate. The density of the float (35) is between the required fluid and the unrequired fluid, so that the float has two working states. When the float (35) moves toward the intermediate shaft, the float channel (32) is opened and the fluid enters the intermediate manifold (4). When the float (35) moves away from the intermediate shaft, the float channel (32) is closed and the fluid is prohibited from entering the intermediate manifold (4).

2. The automatic water control device based on fluid density difference according to claim 1, characterized in that: The production valve (5) is composed of a production valve seat (51), a production valve disc (52), a production valve spring (53) and a collection channel (7). The pressure of the fluid entering the intermediate manifold (4) varies depending on the number of float channels (32) opened by the fluid selector float (35), thereby generating a pressure difference between the upper and lower ends of the production valve disc (52). When fluid enters the intermediate manifold (4), the pressure at the upper and lower ends of the production valve disc (52) does not change much, the valve remains in a normally closed state, and the fluid cannot enter the collection channel (7) through the production valve (5). Conversely, when no fluid enters the intermediate manifold (4), a pressure difference is generated between the upper and lower ends of the production valve disc (52), causing the production valve spring (53) to compress and open the production valve (5), and the fluid enters the collection channel (7).

Images