Automatic water control device based on fluid density difference

Abstract

The invention discloses an automatic water control device based on fluid density difference. The automatic water control device mainly solves the problem of how to successfully achieve water control and oil increase in oil reservoirs with similar formation fluid viscosity in the prior art. The device comprises a shell, a baffle, a fluid selector sealed in the shell and the baffle, a production valve, a pressure relief one-way valve and a collecting channel for fluid to flow in finally. By means of the scheme, the purposes that formation fluid is used for driving the fluid selector to rotate so that the production valve can be opened in oil and closed in water are achieved, the water control and oil increase effect based on density is achieved, and the high practical and popularization value is achieved.

Description

Technical Field

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

[0002] Horizontal well mining is one of the priority mining technologies for oil and gas reservoirs in recent years, and has been widely used in the development of various types of oil reservoirs. With the promotion and application of horizontal well technology, this technology has gradually exposed some problems that cannot be ignored. Due to the heterogeneity of permeability at various positions in the formation and the pressure drop along the flow direction of the wellbore, the inflow profile of the horizontal wellbore is uneven, which is prone to produce a pressure drop funnel, premature water or gas, and a sharp drop in production. Such problems often seriously affect the oil production and economic benefits of the oil well. In severe cases, it can even lead to violent flooding of the horizontal well, forcing the oil well to be shut down, resulting in great losses to the oil well.

[0003] In order to balance the flow of fluid along the wellbore of horizontal wells and delay water inrush, the new water control completion methods for horizontal wells that have been widely used at home and abroad in recent years mainly include: 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 has been designed and determined before installation. Unless the well is re-completed, its water control strength cannot be changed after installation. Continuous packer ICD water control refers to the reduction or elimination of annular flow and its adverse effects on completion performance by lowering continuous packers on the basis of ICD water control completion. The AICD water control valve can automatically adjust the additional pressure drop it generates according to the downhole fluid conditions, and can achieve the purpose of water control by providing a larger additional pressure drop for low-viscosity fluids.

[0004] At present, domestic patents on AICD mainly rely on the fact that high-viscosity oil takes fewer paths in AICD, while low-viscosity water takes more paths to achieve the effect of controlling water and increasing oil production. The design method of AICD flow channel parameters with Chinese patent application number 201610946014.1 and an AICD water control device with Chinese patent application number 201811080478.4 both perform separation when there is a viscosity difference between oil and water, but do not consider the problem that the viscosity difference is not obvious due to the high water output in the later stage of the oil well, and the existing AICD has a very large pressure drop under the action of high-speed fluid in the formation. As the oil well is produced, the original reservoir saturation will decrease, while the water saturation is relatively high, and the water near the bottom of the well is relatively easier to be produced. The AICD water control valve based on fluid viscosity cannot work well, so there is an urgent need for a new AICD that does not rely on fluid viscosity differences and can work normally when the fluid pressure drop is small. Summary of the invention

[0005] Based on the aforementioned prior art's defect that AICD cannot perform separation well due to the small difference in oil and water viscosity in the later stage of oil and gas wells, 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 difference in oil and water density, promote the separation of oil and water, and have a better effect of increasing oil and controlling water.

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

[0007] An automatic water control device based on fluid density difference includes: a housing, a fluid selector, a production valve, a pressure relief check valve and a collection channel. Here, oil-water separation is used as an example to illustrate the function of the device, but the device is not limited to oil-water separation, but is applicable to the separation of any fluid with 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 the fluid selector by means of threads. The first chamber has a side channel connected to the second chamber; the second chamber of the production valve is fixed by bolt connection, and a production valve outlet is provided at the bottom to connect to the collecting channel. The second chamber and the third chamber are connected by a central channel; the third chamber of the pressure relief one-way valve is fixed by means of threads or the like, and the one-way valve outlet at the bottom is connected to the collecting channel.

[0009] Furthermore, an embodiment of a fluid selector is proposed. The fluid rotator can rotate radially around the intermediate axis, and the inflowing fluid drives the impeller to rotate, generating centripetal acceleration through rotation, which can easily reach more than 30 times the gravitational acceleration g, so that the influence of gravity on the float can be ignored.

[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 toward the middle axis in a fluid with a lower density than itself, and moves away from the middle axis in a fluid with a higher density than itself. The float moves toward or away from the middle axis, resulting in different numbers of float channels opening, thereby obtaining the required effective density of fluid as much as possible.

[0012] Furthermore, a groove of a certain width is provided between the float channel and the intermediate shaft, which can ensure that during the rotation, the fluid can still enter the interior of the intermediate shaft through the opened float channel, thereby ensuring the stability of the flow rate.

[0013] Furthermore, an intermediate manifold is connected above the intermediate shaft, and the fluid entering the interior of the intermediate shaft flows into the bottom of a subsequent production valve according to the opening condition of the float channel.

[0014] Furthermore, a flow channel is reserved at the bottom of the production valve for connecting 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.

[0015] Furthermore, when the fluid is a fluid of the required effective density, such as oil, the float moves toward 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.

[0016] Furthermore, when the fluid is an unnecessary fluid of non-effective density, such as water, the float moves away from the intermediate axis, the float channel opens, fluid passes through the intermediate manifold, the bottom of the production valve receives the fluid flowing in from the intermediate 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 oil pipeline.

[0017] Furthermore, the fluid that does not flow into the oil pipeline flows 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 multiple pressure relief ports when the production valve is closed to ensure normal operation.

[0018] In the present method, the fluid selector used to achieve fluid density differentiation may use any existing shapes that can be thought of by those skilled in the art, such as square floats, irregular floats, etc., in addition to the floats.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0020] 1. The present invention drives the fluid selector to rotate by fluid impacting the impeller bearing, allowing the float to move inside the channel relying on the centripetal force and the 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, thus filling the gap in the existing AICD technology.

[0021] 2. The fluid selector of the present invention can accurately control the collected fluid according to the multi-level setting of fluid density. It is suitable for fields such as underground fluid density differences and difficult water-gas separation, and has strong applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] 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:

[0023] Figure 1 It is a schematic diagram of a specific embodiment of the present invention;

[0024] Figure 2 A half-section structural diagram of a specific embodiment of the present invention;

[0025] Figure 3 It is a schematic diagram of the housing structure of a specific embodiment of the present invention;

[0026] Figure 4 It 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;

[0027] Figure 5 This is a schematic diagram of the structure of a fluid selector in a specific embodiment of the present invention;

[0028] Figure 6 It is a schematic diagram of the production valve structure 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 one-way valve, 7-collecting channel, 11-nozzle, 12-first cavity, 13-boss, 14-side flow channel, 15-second cavity, 16-production valve outlet, 17-central flow channel, 18-third cavity, 19-one-way valve outlet, 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 is further described below in conjunction with 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 a 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 inside of the shell 1; the first chamber 12 close to the nozzle contains a fluid selector 3, including a boss 13 base fixed to the shell 1, an intermediate shaft 33 with an internal flow channel connected to the base by a thread or other connection method, a rotatable bearing 34 and an impeller 31 fixed to the intermediate shaft 33, and a float channel 32 inside the intermediate shaft 33 and a density variable Float 35; inside the second cavity 15 is the production valve 5, including a production valve body 51 fixed to the shell 1 by means of 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 inside the third cavity 18 is 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, and the amount of fluid that the pressure relief one-way valve 6 flows into the collection channel 7 is much smaller than the flow rate of the fluid flowing into the collection channel 7 when the production valve 5 is opened.

[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 away from 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 pressure difference generated is small and is not enough to compress the production valve spring, resulting in the fluid being unable to flow into the collection channel through the production valve. Therefore, the fluid continues to flow to the one-way valve, and a small amount flows into the collection channel, so that there is a pressure relief port in this case to keep the entire mechanism able to continue to work normally.

[0035] When the formation fluid oil accounts for a large proportion, the fluid enters through the nozzle and drives the fluid selector impeller to rotate under the action of the bearing. Since the oil density is smaller than the density set by the float, the float moves toward the middle axis, closing the float channel. The fluid cannot flow through the channel to the bottom of the production valve through the middle manifold. However, since there is no fluid at the bottom of the production valve disc and there is fluid above, a large pressure difference is generated to compress the production valve spring. The production valve opens and the fluid flows into the collection channel. A small part of the fluid continues to flow to the one-way valve, and a small amount flows into the collection channel. The amount of fluid flowing into the production valve is much greater than the fluid flowing into the one-way valve. Based on the above principle, the effect of controlling water and increasing oil is achieved.

[0036] Through the above-mentioned example of oil and water separation, the automatic water control device based on fluid density difference of the present invention can open the valve to collect the fluid when the fluid has the density required by the producer; when the fluid has the density not required by the producer, the valve is closed or the valve opening is very small, so that the fluid will not be collected or very little will be collected. In this way, the fluid required by the producer can be automatically selected according to the different fluid densities.

[0037] In order to make the purpose, technical solutions and advantages of the present invention clearer, the schematic 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 the present application, it should be understood that the orientation or positional relationship indicated by terms such as "front", "rear", "left", "right", "upper", "lower", "inside", "outside", etc. is based on the orientation or positional relationship shown in the accompanying drawings, which is 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 the present application.

[0038] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any changes made by adopting the design principles of the present invention and performing non-creative work on this basis should fall within the protection scope of the present invention.

Claims

1. An 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 an internal device is fixed to the upper part of the shell (1) by means of bolts. The shell (1) has three chambers inside. The fluid selector (3) is fixed to the first chamber (12) by means of threads. The production valve (5) is fixed to the inside of the second chamber (15) by means of bolts. The intermediate manifold (4) connects the upper end of the fluid selector (3) and the bottom of the production valve (5). The pressure relief check valve (6) is fixed to the inside of the third chamber (18) by means of threads. The collection channel (7) connected to the bottom of the production valve (5) and the pressure relief check valve (6) is used to collect fluid.

2. The automatic water control device based on fluid density difference according to claim 1, characterized in that: The shell (1) has a nozzle (11) for a fluid inlet device, and the interior of the shell is divided into three chambers. The first chamber (12) has a boss (13), the interior of which is connected to the fluid selector (3) by a thread, and the first chamber (12) has a side channel (14) connected to the second chamber (15); the second chamber (15) of the production valve (5) is fixed by bolt connection, and a production valve outlet (16) is provided at the bottom to connect to the collection channel (7), and the second chamber (15) and the third chamber (18) are connected by a central channel (17); the third chamber (18) of the pressure relief check valve (6) is fixed by a thread, and is connected to the collection channel (7) via the check valve outlet (19) at the bottom.

3. The automatic water control device based on fluid density difference according to claim 1, characterized in that: The fluid selector (3) is composed of an impeller (31), a float channel (32), a shaft body (33) with an internal flow channel, a bearing (34), a float (35), a housing (1), and an intermediate manifold (4) connected to a production valve (5). The impeller (31) and the bearing (34) are mounted on the shaft body (33) with an internal flow channel, so that the fluid drives the impeller (31) to rotate. The density of the float (35) is between the density of the required fluid and the density of the unnecessary fluid, so that the float has two working states. When the float (35) moves away from the shaft body, the float channel (32) is opened and the fluid enters the intermediate manifold (4). When the float (35) moves toward the shaft body, the float channel (32) is closed and the fluid is prohibited from entering the intermediate manifold (4).

4. 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 different numbers of float channels (32) opened by the fluid selector float (35) result in different pressures of the fluid entering the intermediate manifold (4), 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).

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