Ground calibration device for the extrusion pressure-flow relationship curve of casing outer annulus collector

Abstract

The present invention relates to a ground calibration device for the extrusion force-flow relationship curve of a casing outer annulus collector, which includes a large diameter circular pipe section, an extrusion cone valve, a thin conduit, a push rod handle, a screw push rod, and an equivalent external spring. The extrusion cone valve is installed in the large diameter circular pipe section through an arc support seat. The extrusion cone valve collector is composed of a cone valve seat, a cone valve core, a cone core spring, and an inner cavity of the collector. The large diameter circular pipe section has a push rod hole, and the push rod hole is coaxially arranged with the cone valve core. A cylindrical support seat is arranged at the push rod hole, and the cylindrical support seat has an internal thread. The screw push rod is threadedly connected to the cylindrical support seat, and one end of the screw push rod points to the cone valve core. The equivalent external spring is arranged between the push rod handle and the screw push rod and surrounds the outside of the mother push rod. The equivalent external spring is provided with an external elastic pressure gauge. The present invention adopts the equivalent principle of water pressure environment simulation to change the complex casing outer annulus environment into a simple large diameter circular pipe inner water environment, which is convenient for underwater testing of the collector.

Description

Technical Field

[0001] The invention relates to a downhole casing annulus monitoring technology in the field of oil production, and in particular to a ground calibration device for an extrusion pressure-flow relationship curve of a casing annulus collector. Background Art

[0002] In order to monitor the high-pressure water seepage pressure and flow rate changes of the annulus outside the casing online and infer the squeezing force of the formation displacement on the casing, a water parameter collector with stress-strain function is required.

[0003] The strain of the collector's water channel and the extrusion stress it is subjected to can be inferred by the changes in water parameters (pressure, flow, water sample) measured on the ground. However, before the water parameter collector leaves the factory, the curve change law between the characteristic parameters of this type of product (extrusion pressure-channel strain-flow) must be calibrated and tested.

[0004] Therefore, it is very important to design a simple ground test platform and measurement method for the strain performance parameters of the water parameter collector. Summary of the invention

[0005] One object of the present invention is to provide a ground calibration device for the squeeze pressure-flow relationship curve of a casing outer annulus collector, which is used to study and online monitor the changing law of casing damaged wells.

[0006] The technical solution adopted by the present invention to solve its technical problems is: the ground calibration device of the extrusion pressure-flow relationship curve of the casing outer annulus collector comprises a large diameter circular pipe section, an extrusion cone valve, a thin guide tube, a push rod handle, a screw push rod, and an equivalent external spring. The extrusion cone valve is installed in the large diameter circular pipe section through an arc-shaped support seat. The extrusion cone valve collector is composed of a cone valve seat, a cone valve core, a cone core spring, and a collector inner cavity. The arc-shaped support seat buckle is placed on the inner wall of the large diameter circular pipe section. The collector inner cavity is arc-shaped. The bottom of the collector inner cavity cooperates with and is fixed on the arc-shaped support seat. The top of the collector inner cavity has an opening, and a cone valve seat is arranged at the opening. The cone valve seat has an annular water inlet channel. One end of the cone core spring is fixed to the bottom of the collector inner cavity, and the other end of the cone core spring is connected to the cone valve core. The cone valve core and The annular water inlet channel is matched, one end of the thin catheter is located in the inner cavity of the collector, the diameter of the thin catheter is equivalent to the thickness of the inner cavity of the collector, and the other end of the thin catheter extends out of the large diameter circular tube section; the large diameter circular tube section has a push rod hole, the push rod hole is coaxially arranged with the cone valve core, a cylindrical support seat is arranged at the push rod hole, the cylindrical support seat has an internal thread, the screw push rod is threadedly connected with the cylindrical support seat, one end of the screw push rod points to the cone valve core, the other end of the screw push rod is connected to the push rod handle through the female push rod, the equivalent external spring is arranged between the push rod handle and the screw push rod and surrounds the outside of the female push rod, and the equivalent external spring is arranged with an external elastic pressure gauge; a high-pressure infiltration water channel is arranged at the large diameter circular tube section corresponding to the arc support seat, a water pressure gauge is arranged on the high-pressure infiltration water channel, and a flow meter is installed at one end of the thin catheter extending out of the large diameter circular tube section.

[0007] In the above scheme, the push rod handle is rotated. When the push rod handle is screwed in, the front end of the screw push rod presses the cone core spring, so that the cone valve core moves downward and gradually closes the annular water inlet channel. At the same time, the push rod handle presses the equivalent outer spring, so that the equivalent outer spring moves, and the extrusion pressure value F is read on the external elastic pressure gauge, and the corresponding flow value Q is read on the flow meter installed on the capillary tube;

[0008] Rotate the push rod handle again, read the new extrusion force F and the corresponding flow value Q, repeat several times until the cone valve is closed, at which time the extrusion force is the maximum, and the maximum extrusion force F is obtained. M , and the flow rate Q = 0, completing the calibration relationship curve between the extrusion force F and the corresponding flow rate Q of the tested model extrusion cone valve collector.

[0009] The present invention has the following beneficial effects:

[0010] 1. The present invention establishes a functional (curve) relationship between the extrusion pressure on the collector and the corresponding water flow rate outside the deep well casing.

[0011] 2. The present invention is the first to design and construct a ground calibration test platform for the relationship between the extrusion pressure and flow rate of an external collector on the ground.

[0012] 3. The present invention uses an elastic cone valve core and a cone valve seat structure to determine the functional relationship between the external extrusion force F and the water flow rate, thereby realizing that the extrusion force of the underground formation swelling movement on the collector and casing can be inferred through the change of the surface flow of the fine tube.

[0013] 4. The present invention adopts the equivalent principle of water pressure environment simulation to change the complex annular space environment outside the casing into a simple water environment inside a large-diameter circular tube, which is convenient for underwater testing of the collector.

[0014] 5. The present invention adopts the principle of equivalent elastic force of paired springs. By testing the elastic force of paired springs on the same top rod outside a large-diameter water pipe, it represents the elastic force in the water environment inside the pipe and also represents the squeezing force of stratum movement. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the structure of the present invention;

[0016] Figure 2 It is the relationship diagram between the displacement of the cone valve and the reduced width of the annular water inlet channel;

[0017] Figure 3 It is the standard relationship curve between extrusion force F and channel flow Q;

[0018] Figure 4 It is a schematic diagram of the collector's squeeze valve and fine conduit installed in the outer annulus of the deep well casing;

[0019] Figure 5 This is a schematic diagram of the pressure on the extrusion cone valve collector.

[0020] In the figure: 1 large diameter round pipe section; 2 thin conduit; 3 push rod handle; 4 screw push rod; 5 equivalent external spring; 6 cone valve seat; 7 cone valve core; 8 cone core spring; 9 collector cavity; 10 arc support seat; 11 cylindrical support seat; 12 female push rod; 13 external elastic pressure gauge; 14 high pressure infiltration water channel; 15 water pressure gauge; 16 annular water inlet channel; 17 casing; 18 extrusion cone valve. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings:

[0022] Combination Figure 1-Figure 5As shown, the ground calibration device of the extrusion force-flow relationship curve of the casing outer annulus collector includes a large diameter circular pipe section 1, an extrusion cone valve collector, a thin guide tube 2, a push rod handle 3, a screw push rod 4, and an equivalent external spring 5. The extrusion cone valve 18 is installed in the large diameter circular pipe section 1 through an arc support seat 10. The extrusion cone valve collector is composed of a cone valve seat 6, a cone valve core 7, a cone core spring 8, and a collector inner cavity 9. The arc support seat 10 is buckled on the inner wall of the large diameter circular pipe section 1. The collector inner cavity 9 is arc-shaped. The bottom of the collector inner cavity 9 cooperates with the arc support seat 10 and is fixed on the arc support seat 10. The top of the collector inner cavity 9 has an opening, and a cone valve seat 6 is arranged at the opening. The cone valve seat 6 has an annular water inlet channel 16. One end of the cone core spring 8 is fixed to the bottom of the collector inner cavity 9, and the other end of the cone core spring 8 is connected to the cone valve core 7. The cone valve core 7 and the annular water inlet channel 16 cooperates with each other, one end of the thin catheter 2 is located in the collector cavity 9, the diameter of the thin catheter 2 is equivalent to the thickness of the collector cavity 9, and the other end of the thin catheter 2 extends out of the large diameter circular tube section 1; the large diameter circular tube section 1 has a push rod hole, the push rod hole and the cone valve core 7 are coaxially arranged, a cylindrical support seat 11 is arranged at the push rod hole, the cylindrical support seat 11 has an internal thread, the screw push rod 4 is connected to the internal thread of the cylindrical support seat, one end of the screw push rod 4 points to the cone valve core 7, the other end of the screw push rod 4 is connected to the handle, the equivalent external spring 5 is arranged between the push rod handle 3 and the screw push rod 4 and surrounds the outside of the female push rod 12, and the equivalent external spring 5 is provided with an external elastic pressure gauge 13; a high-pressure water infiltration channel 14 is arranged at the large diameter circular tube section corresponding to the arc support seat 10, a water pressure gauge 15 is arranged on the high-pressure water infiltration channel 14, and a flow meter is installed at one end of the thin catheter 2 extending out of the large diameter circular tube section.

[0023] 1. Function of squeeze cone valve collector:

[0024] The cone valve core 7 is connected to the cone core spring 8, and the extrusion cone valve 18 is arranged outside the arc support seat 10. The arc support seat 10 is used to simulate the casing, imitating that when the swelling formation moves and starts to squeeze the valve core at the protruding position, the valve core moves inward to reduce the cross-sectional area of ​​the water inlet channel. Figure 5 .

[0025] ① The extrusion pressure gradually increases

[0026] ②The cone valve core 7 gradually moves inwards

[0027] ③ After the cone core spring 8 is compressed, the reverse elastic force also increases, and is equal to the rock formation extrusion force in magnitude and opposite in direction.

[0028] ④ The cone valve core 7 is squeezed and moves inward, causing the flow cross section of the water inlet channel to gradually decrease.

[0029] ⑤ The cross-section of the annular water inlet channel 16 becomes smaller, so that the water inlet flow rate (i.e. the water flow rate tested by the ground capillary tube) gradually decreases until the extrusion pressure is very large (the pressure threshold when the cone valve is closed), the cone valve is closed, and the water inlet of the collector is zero.

[0030] Before this type of collector leaves the factory, the above squeeze pressure-channel change-flow change relationship curve must be measured and calibrated. When the collector is squeezed after being lowered into the well, the flow measured on the ground is reversed on the above calibration curve to find out the corresponding formation squeeze pressure. The goal of quantitatively inferring the change of underground formation squeeze pressure through the flow change of the fine pipe on the ground is achieved.

[0031] 2. Calibration method of extrusion pressure-flow relationship curve of elastic cone valve of extrusion cone valve collector:

[0032] 1. The quantitative relationship between the displacement ΔL of the elastic cone valve and the pressure F

[0033] F = K × ΔL, where K is the elastic modulus

[0034] When there is no extrusion force F=0, the displacement ΔL=0

[0035] When the displacement is maximum (i.e. the cone valve is closed), ΔL = ΔL M (maximum stroke), squeeze F = F M The pressure reaches the maximum value of the measuring capacity F M .

[0036] 2. The proportional relationship between the displacement ΔL of the elastic cone valve and the reduced width ΔW of the water inlet channel, see Figure 2 ,

[0037] ΔW / ΔL=sinα α-inclination angle of cone valve cone core

[0038] That is, ΔW = ΔL·sinα or

[0039] 3. The increase of elastic extrusion force F moves the extrusion cone valve core downward, reducing the width of the water inlet channel by Δl. Combining the formulas in 1 and 2 above, the relationship between F and ΔL is obtained.

[0040]

[0041] When the extrusion pressure F increases to a certain threshold value F M When the water inlet channel width is reduced by ΔW, it will be equal to the water inlet channel width before the cone core moves downward. In this working condition, the cone valve is closed and there is no water inlet.

[0042] 4. Relationship between extrusion pressure F and water flow rate of annular channel Q

[0043] Simple estimation method:

[0044] (1) Based on the formula in 3 above, the function of the flow channel change ΔW and the extrusion force F is given

[0045] F=f(ΔW)

[0046] (2) From the function of flow rate and flow cross section in an annular channel in fluid mechanics:

[0047] Q=g(ΔW)

[0048] By combining (1) and (2) above, the quantitative relationship between the pressure F and the flow rate Q of the collector of this model can be calculated.

[0049] Before this type of collector leaves the factory, a calibration test bench is required to calibrate the relevant fixed parameters of the cone valve. The above formula can then be used to quantitatively calculate the corresponding value of the relationship between the extrusion pressure F and the channel flow Q.

[0050] Or use a calibration test bench to directly measure and draw a standard relationship curve between extrusion pressure F and channel flow Q for checking.

[0051] In oilfield downhole applications, the above formula or calibrated relationship curve can be used to infer the squeezing force F of the downhole collector and casing caused by the swelling and movement of the mudstone layer in the annulus outside the deep well casing by the change of the catheter flow Q monitored on the ground.

[0052] 3. The present invention realizes the design of the device through the water flow environment equivalent method:

[0053] In actual application, the squeeze valve (cone valve) and water inlet end of the collector are installed in the outer annulus of the deep well casing. Figure 4 The bottom of the inner cavity of the collector of the present invention cooperates with the arc-shaped support seat 10 and is fixed on the arc-shaped support seat 10 for simulation, wherein the arc-shaped support seat 10 is used to simulate the sleeve 17.

[0054] The high-pressure leakage water in the annulus outside the casing enters the inner cavity 9 of the collector through the water channel of the cone valve, and then flows into the ground measurement system through the thin conduit 2 connected thereto.

[0055] The length of the thin tube 2 is actually nearly a kilometer, but due to the uniformity of the resistance coefficient along the way, when calibrating and measuring on the ground, only a small section (such as 1 meter long) needs to be selected and placed horizontally, and the formula is used:

[0056] ΔP L =δ L Q L ,

[0057] δ L =ΔP L / Q L

[0058] Where: Q L ——1 meter capillary flow

[0059] ΔP L - Pressure difference between the two ends of a 1 meter thin tube

[0060] δ L -The negative force coefficient along the 1m thin tube

[0061] The water environment of the collector can be equivalently placed in a large diameter circular pipe (such as 1 meter). The internal water environment effect is the same as the annular space outside the casing, and the water environment inside the large diameter pipe can simulate the water environment outside the casing inside.

[0062] 4. The quantitative relationship between the extrusion force F and the channel flow Q of the cone valve of the calibration measurement collector of the present invention is:

[0063] In order to determine the pressure value of the pressure spring on the cone valve core, a matching spring (i.e., an equivalent outer spring 5) of the same type and working condition (with the same initial preload force, for example, the preload force is zero) can be placed on the outside of the screw push rod 4 (outside the large diameter tube).

[0064] When the rotating push rod handle 3 is screwed in, the front end of the screw push rod 4 presses the cone core spring 8, so that the cone valve core 7 moves downward and gradually closes the annular water inlet channel 16. At the same time, the push rod handle 3 presses the equivalent outer spring 5, so that the equivalent outer spring 5 moves, and the extrusion force value F is read on the external elastic pressure gauge 13, and the corresponding flow value Q is read in the flow meter installed on the capillary tube 2;

[0065] Rotate the push rod handle 3 again, read the new extrusion force F and the corresponding flow value Q, repeat several times until the cone valve is closed and the extrusion force is maximum, and get the maximum extrusion force F M At this time, the flow rate Q = 0, and the calibration relationship curve between the extrusion force F and the corresponding flow rate Q of the tested model extrusion cone valve collector is completed. Figure 3 .

Claims

1. A ground calibration device for the extrusion pressure-flow relationship curve of a casing outer annulus collector, characterized by: The ground calibration device of the extrusion pressure-flow relationship curve of the casing outer annulus collector comprises a large diameter circular pipe section, an extrusion cone valve, a fine guide tube, a screw mandrel, and an equivalent external spring. The extrusion cone valve is installed in the large diameter circular pipe section through an arc-shaped support seat. The extrusion cone valve collector is composed of a cone valve seat, a cone valve core, a cone core spring, and a collector inner cavity. The arc-shaped support seat buckle is placed on the inner wall of the large diameter circular pipe section. The collector inner cavity is arc-shaped. The bottom of the collector inner cavity cooperates with and is fixed on the arc-shaped support seat. The top of the collector inner cavity has an opening, and a cone valve seat is arranged at the opening. The cone valve seat has an annular water inlet channel. One end of the cone core spring is fixed to the bottom of the collector inner cavity, and the other end of the cone core spring is connected to the cone valve core. The cone valve core cooperates with the annular water inlet channel. The fine guide tube One end is located in the inner cavity of the collector, the diameter of the thin catheter is equivalent to the thickness of the inner cavity of the collector, and the other end of the thin catheter extends out of the large diameter circular tube section; the large diameter circular tube section has a push rod hole, the push rod hole is coaxially arranged with the cone valve core, a cylindrical support seat is arranged at the push rod hole, the cylindrical support seat has an internal thread, the screw push rod is threadedly connected with the cylindrical support seat, one end of the screw push rod points to the cone valve core, the other end of the screw push rod is connected to the push rod handle through the female push rod, the equivalent external spring is arranged between the push rod handle and the screw push rod and surrounds the outside of the female push rod, and the equivalent external spring is provided with an external elastic pressure gauge; a high-pressure infiltration water channel is arranged at the large diameter circular tube section corresponding to the arc support seat, a water pressure gauge is arranged on the high-pressure infiltration water channel, and a flow meter is installed at one end of the thin catheter extending out of the large diameter circular tube section; Calibration method of extrusion pressure-flow relationship curve of elastic cone valve of extrusion cone valve collector: (I) The quantitative relationship between the displacement ΔL of the elastic cone valve and the extrusion force F: F = K × ΔL, where K is the elastic modulus (1) When there is no extrusion force F=0, the displacement ΔL=0 When the displacement is maximum ΔL=ΔL M When the extrusion pressure F = F M , reaching the maximum value of the measurement capability F M ; (II) Proportional relationship between the displacement ΔL of the elastic cone valve and the reduced width ΔW of the water inlet channel: ΔW / ΔL=sinα; α-the inclination angle of the cone core of the cone valve (2) That is, ΔW = ΔL·sinα or (III) The increase of extrusion pressure F moves the extrusion cone valve core downward, reducing the width of the water inlet channel. Combining equations (1), (2) and (3), we can obtain the relationship between F and ΔF: When the extrusion pressure F increases to a certain threshold value F M When , the water inlet channel is reduced in width ΔW, which is equal to the width of the water inlet channel before the cone core moves downward. In this working condition, the cone valve is closed and there is no water inflow. (IV) The relationship between the extrusion pressure F and the water flow rate Q of the annular channel: a. Formula (4) gives the function of the reduced width ΔW of the water inlet channel and the extrusion pressure F F=f(ΔW) (5) b. Functional formula of flow rate and flow cross section in annular channel in fluid mechanics Q=g(ΔW) (6) c. Combine equation (5) with equation (6) to calculate the quantitative relationship between the extrusion force F of the extrusion cone valve collector and the water inlet flow rate Q of the annular channel; Rotate the push rod handle. When the push rod handle is screwed in, the front end of the screw push rod presses the cone core spring, causing the cone valve core to move downward and gradually close the annular water inlet channel. At the same time, the push rod handle presses the equivalent outer spring to move the equivalent outer spring. The extrusion force value F is read on the external elastic pressure gauge, and the corresponding annular channel water inlet flow Q is read on the flow meter installed on the capillary tube. Rotate the push rod handle again, read the new extrusion force F and the corresponding annular channel water flow value Q, repeat several times until the cone valve is closed, the extrusion force is the maximum, and the maximum extrusion force F is obtained. M , the water inlet flow rate Q of the annular channel is 0, and the calibration relationship curve between the extrusion pressure F of the tested model extrusion cone valve collector and the corresponding water inlet flow rate Q of the annular channel is completed.

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