CN114923848B - Device and method for evaluating flushing efficiency of high-temperature high-pressure well cementation two interfaces - Google Patents

Abstract

The invention discloses a method for detecting flushing efficiency of two interfaces of high-temperature high-pressure well cementation, which comprises the steps of selecting corresponding stirring cylinders through on-site annular gaps, installing the corresponding stirring cylinders on a magnetic stirrer, and sealing a kettle body; then pumping flushing liquid, determining flushing time according to experiment requirements, and adjusting the temperature and pressure of the kettle body to the temperature and pressure required by the experiment; according to different on-site flushing fluid types, different rotating speed formulas are adopted, the rotating speed of the outer cylinder is calculated according to the construction displacement and the annular space, and the initial fluid loss flow Q ₀ of the artificial rock core is measured and recorded through a real-time flowmeter; pumping drilling fluid into the kettle body, heating and boosting, starting a magnetic stirrer, simulating the hydraulic filtration of the drilling fluid to form mud cakes, and measuring and recording the flow Q ₁ of the drilling fluid through a real-time flowmeter. The invention has the characteristics of simple operation, real time and accuracy.

Description

A device and method for evaluating flushing efficiency of two interfaces of high temperature and high pressure cementing

Technical Field

The invention relates to the technical field of petroleum engineering, in particular to a method for detecting flushing efficiency of a high-temperature and high-pressure cementing interface.

Background Art

During the drilling process, under the action of pressure difference, the drilling fluid will be lost and form a mud cake on the well wall, which will deteriorate the bonding quality between the cement ring and the formation rock. Under the action of the change in wellbore internal pressure, the cement ring and the formation rock will peel off and produce microcracks, resulting in failure of the cement ring seal and triggering oil, gas and water channeling.

Therefore, the mud cake must be removed during cementing. Flushing fluid is usually used to flush the mud cake on the well wall to improve the bonding quality of the cementing interface and increase the bonding strength. The flushing efficiency of the flushing fluid determines the flushing capacity of the flushing fluid. The development and optimization of the flushing fluid system can be achieved through the evaluation of the flushing efficiency.

To this end, domestic and foreign scholars have proposed a series of devices and methods for evaluating the flushing efficiency of the two interfaces of cementing. The domestic patents for devices and methods for evaluating the flushing efficiency of the two interfaces include: "A cementing flushing fluid evaluation device and method based on the principle of equal shear rate" (CN103541675B); "A cementing flushing efficiency evaluation device and method" (CN104863533); "A cementing flushing fluid evaluation device and experimental method based on the formation of dynamic mud cake" (CN104849404); "A drilling fluid filter cake compression and cleaning efficiency integrated evaluation device and method" (CN110107235A); "Cementing cement drilling fluid filter cake flushing efficiency evaluation device and method" (CN110617018A). Many domestic scholars have also published papers on the evaluation of the flushing efficiency of the two interfaces, such as: Gu Tao et al. Evaluation method for flushing efficiency of cementing pre-flushing fluid-improved rotational viscometer method [J]. Natural Gas Industry, 2020, 40(11); Li Shekun et al. Shale gas horizontal well flushing efficiency evaluation device [J]. Petroleum Machinery, 2016, 44(09); Li Shaoli et al. A visual flushing fluid evaluation device and method [J]. Drilling Fluid and Completion Fluid, 2016, 33(02); Zhu Jianglin et al. A physical simulation flushing fluid evaluation method [J]. Drilling Fluid and Completion Fluid, 2012, 29(01); Wang Guanglei et al. A new flushing efficiency evaluation method [J]. Drilling Fluid and Completion Fluid, 2011, 28(03); You Fuchang et al. A method for evaluating the flushing efficiency of cementing pre-flushing fluid [J]. Drilling Fluid and Completion Fluid, 2009, 26(06), etc. Foreign scholars include: Choi M et al. determined the thickness of mud cake before and after flushing through fluorescence measurement, and then evaluated the flushing efficiency (Choi M, etc. Novel methodology to evaluate displacement efficiency of drilling mud using fluorescence in primary cementing [J]. Journal of Petroleum Science & Engineering, 2018, 165: 647-654)

The existing detection methods cannot truly simulate the actual environment downhole, cannot truly simulate the mud cake formation process, can only measure the flushing efficiency at a certain time, and the measured results are far from the actual values downhole.

Therefore, it is necessary to design a method that is simple to operate, real-time and accurate to detect the flushing efficiency of the second interface of high-temperature and high-pressure cementing.

Summary of the invention

The object of the present invention is to provide a method for detecting the flushing efficiency of the second interface of high-temperature and high-pressure cementing, so as to solve the problems raised in the above-mentioned background technology.

In order to solve the above technical problems, the present invention provides the following technical solutions: a method for detecting the flushing efficiency of the second interface of high-temperature and high-pressure cementing, the method adopts a flushing efficiency evaluation device, the flushing efficiency evaluation device comprises: a kettle, an artificial core, a core clamp, a mixing drum, a magnetic stirrer, a metal filter and a real-time flow meter; wherein the kettle is connected to both the flushing fluid tank and the drilling fluid tank, and is provided with a temperature sensor for detecting the temperature in the kettle and a pressure sensor for detecting the pressure in the kettle, the temperature sensor and the pressure sensor are both connected to a computer through a bus; the artificial core is detachably fixed to the inner bottom of the kettle through the core clamp, and the core clamp is used to fix the core of the kettle to the inner bottom of the kettle. The core holder is detachably fixed to the inner bottom of the kettle body; the mixing drum is inverted onto the artificial core, and the inner top thereof is not in contact with the artificial core, and is used to simulate the dynamic filtration of drilling fluid to form mud cakes and the rotation speed under different annular gaps; the magnetic stirrer is located at the top of the kettle body, and its stirring rod passes through the top of the kettle body and is fixed to the top of the mixing drum to drive the rotation of the mixing drum; the metal filter is sleeved on the artificial core; a drainage hole is provided at the position where the core holder is installed on the kettle body, and the drainage hole is connected to the artificial core; the real-time flow meter is provided on the drainage hole of the kettle body, and is connected to the computer through a bus to measure the flow rate of the discharged liquid;

The method includes:

(S1) Select a mixing drum corresponding to the annular gap on site, install it on a magnetic stirrer, and seal the kettle body; then, pump in the flushing liquid, determine the flushing time according to the experimental needs, and adjust the temperature and pressure of the kettle body to the temperature and pressure required by the experiment; use different speed formulas according to the different types of flushing liquids on site, and then calculate the outer drum speed according to the construction displacement and the annular gap, and measure and record the initial filtration flow Q ₀ of the artificial core through a real-time flow meter;

(S2) Pumping drilling fluid into the kettle, increasing the temperature and pressure, turning on the magnetic stirrer, simulating the dynamic filtration of the drilling fluid to form a mud cake, and measuring and recording the flow rate Q ₁ of the drilling fluid by a real-time flow meter;

(S3) Pumping out the drilling fluid from the kettle body and pumping in the flushing fluid. The outer cylinder speed, pressure, temperature, flushing fluid dosage and overall flushing time parameters are set to be consistent with the above parameters. Flushing is performed. The water loss flow Q ₂ can be read in real time by the real-time flow meter, and the flushing efficiency is measured as follows:

The outer cylinder speed is:

(1) When the flushing fluid is Bingham fluid, the outer cylinder speed formula is as follows:

Wherein, λ is the ratio of the radius of the artificial core to the rotating outer cylinder; _D1 is the borehole diameter, in m; _D2 is the outer diameter of the casing, in m; w is the annular gap, in m; Q is the operation displacement, in ^m3 /min; n is the outer cylinder rotation speed, in r/min; _τ0 is the dynamic shear force of the Bingham fluid, in Pa; η is the plastic viscosity, in mPa·s;

(2) When the flushing fluid is a power-law fluid, the outer cylinder speed formula is as follows:

Where, λ is the ratio of the radius of the artificial core to the rotating outer cylinder; _D1 is the borehole diameter, in m; _D2 is the outer diameter of the casing, in m; w is the annular gap, in m; Q is the construction displacement, in m ³ /min; n is the outer cylinder rotation speed, in r/min; _nm is the flow index of the power-law fluid;

(3) When the flushing fluid is a Newtonian fluid, that is, _nm is 1, the outer cylinder speed formula is as follows:

Where, λ is the ratio of the radius of the artificial core to the rotating outer cylinder; _D1 is the borehole diameter, in m; _D2 is the outer diameter of the casing, in m; w is the annular gap, in m; Q is the construction displacement, in m ³ /min; n is the outer cylinder rotation speed, in r/min;

The rotating outer cylinder is the mixing cylinder; the wellbore diameter, casing outer diameter, annular space gap and construction displacement are all construction site parameters;

The radius of the mixing drum (4) can be determined by the borehole diameter, casing outer diameter and core radius, and the formula is as follows:

Wherein, _D2 is the borehole diameter, in mm; _D1 is the outer diameter of the casing, in mm; _R2 is the radius of the mixing drum (4), in mm; _R1 is the core radius, in mm; the above units need to be converted to be consistent during calculation.

According to the above technical solution, in the method (S1) and (S3), the temperature is 20-200°C, the pressure is 0.1-30MPa, and the core size is 24.5mm*75mm.

Compared with the prior art, the beneficial effects achieved by the present invention are:

The present invention can carry out experiments under high temperature and high pressure environment, and simulate the flushing efficiency under different high temperature and high pressure, annular space gap and displacement through the principle of equal wall shear rate. A series of data is obtained by using water loss method, and the flushing efficiency can be measured and calculated in real time.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

FIG1 is a schematic structural diagram of the overall device of the present invention;

FIG2 is a schematic diagram of a curve showing the change of flushing efficiency over time when the flushing liquid of the present invention is a Newtonian fluid and the temperature is 60° C.;

FIG3 is a schematic diagram of a curve showing the change of flushing efficiency over time when the flushing liquid of the present invention is a Newtonian fluid and the temperature is 75° C.;

FIG4 is a schematic diagram of a curve showing the change of flushing efficiency over time when the flushing liquid of the present invention is a Newtonian fluid and the temperature is 90° C.;

5 is a schematic diagram of a curve showing the change of flushing efficiency over time when the flushing fluid of the present invention is a Bingham fluid and the temperature is 60° C.;

FIG6 is a schematic diagram of a curve showing the change of flushing efficiency over time when the flushing fluid of the present invention is a Bingham fluid and the temperature is 75° C.;

7 is a schematic diagram of a curve showing the change of flushing efficiency over time when the flushing fluid of the present invention is a Bingham fluid and the temperature is 90° C.;

Fig. 8 is a schematic diagram of the device of the present invention;

In the figure: 1. kettle body; 2. artificial core; 3. core holder; 4. stirring drum; 5. magnetic stirrer; 6. real-time flow meter.

DETAILED DESCRIPTION

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Please refer to Figures 1-8. The present invention provides a technical solution: a method for detecting the flushing efficiency of the second interface of high-temperature and high-pressure cementing, the method adopts a flushing efficiency evaluation device, the flushing efficiency evaluation device includes: a kettle 1, an artificial core 2, a core clamp 3, a mixing drum 4, a magnetic stirrer 5, a metal filter and a real-time flow meter 6; wherein the kettle 1 is connected to both the flushing fluid tank and the drilling fluid tank, and is provided with a temperature sensor for detecting the temperature in the kettle 1 and a pressure sensor for detecting the pressure in the kettle 1, and the temperature sensor and the pressure sensor are both connected to the computer through a bus; the artificial core 2 is detachably fixed to the inner bottom of the kettle 1 by the core clamp 3, and the core clamp 3 is detachably fixed to the inner bottom of the kettle 1; the mixing drum 4 is inverted onto the artificial core 2 , and the top of the interior thereof is not in contact with the artificial core 2, which is used to simulate the dynamic loss of drilling fluid to form mud cakes and the rotation speed under different annular gaps; the magnetic stirrer 5 is located at the top of the kettle body 1, and its stirring rod passes through the top of the kettle body 1 and is fixed to the top of the stirring drum 4, which is used to drive the rotation of the stirring drum 4; the metal filter is sleeved on the artificial core 2; a drainage hole is provided at the position where the core holder 3 is installed on the kettle body 1, and the drainage hole is connected to the artificial core 2; the real-time flowmeter 6 is provided on the drainage hole of the kettle body 1, and is connected to the computer through a bus, and is used to measure the flow rate of the discharged liquid;

The method includes:

(S1) Select the corresponding mixing drum 4 according to the annular gap on site, install it on the magnetic stirrer 5, and close the kettle body 1; then, pump in the flushing liquid, determine the flushing time according to the experimental needs, and adjust the temperature and pressure of the kettle body 1 to the temperature and pressure required by the experiment; use different speed formulas according to the different types of flushing liquid on site, and then calculate the outer drum speed according to the construction displacement and the annular gap, and measure and record the initial filtration flow Q ₀ of the artificial core 2 through the real-time flow meter 6;

(S2) Pumping drilling fluid into the kettle 1, raising the temperature and pressure, turning on the magnetic stirrer 5, simulating the dynamic filtration of the drilling fluid to form a mud cake, and measuring and recording the flow rate _Q1 of the drilling fluid through the real-time flow meter 6;

(S3) Drilling fluid is pumped out from the kettle 1, and flushing fluid is pumped in. The outer cylinder speed, pressure, temperature, flushing fluid dosage and overall flushing time parameters are set to be consistent with the above parameters. Flushing is performed. The water loss flow rate Q ₂ can be read in real time by the real-time flow meter 6, and the flushing efficiency is measured as follows:

The outer cylinder speed is:

(1) When the flushing fluid is Bingham fluid, the outer cylinder speed formula is as follows:

Wherein, λ is the ratio of the radius of the artificial core 2 to the rotating outer cylinder; _D1 is the borehole diameter, in m; _D2 is the outer diameter of the casing, in m; w is the annular gap, in m; Q is the operation displacement, in ^m3 /min; n is the outer cylinder rotation speed, in r/min; _τ0 is the dynamic shear force of the Bingham fluid, in Pa; η is the plastic viscosity, in mPa·s;

(2) When the flushing fluid is a power-law fluid, the outer cylinder speed formula is as follows:

Wherein, λ is the ratio of the radius of the artificial core 2 to the rotating outer cylinder; _D1 is the borehole diameter, in m; _D2 is the outer diameter of the casing, in m; w is the annular gap, in m; Q is the construction displacement, in m ³ /min; n is the outer cylinder rotation speed, in r/min; _nm is the flow index of the power-law fluid;

(3) When the flushing fluid is a Newtonian fluid, that is, _nm is 1, the outer cylinder speed formula is as follows:

Wherein, λ is the ratio of the radius of the artificial core 2 to the rotating outer cylinder; _D1 is the borehole diameter, in m; _D2 is the outer diameter of the casing, in m; w is the annular gap, in m; Q is the construction displacement, in m ³ /min; n is the outer cylinder rotation speed, in r/min;

The rotating outer cylinder is the mixing cylinder 4; the wellbore diameter, casing outer diameter, annular space gap and construction displacement are all construction site parameters;

The radius of the mixing drum (4) can be determined by the borehole diameter, casing outer diameter and core radius, and the formula is as follows:

Wherein, _D2 is the borehole diameter, in mm; _D1 is the outer diameter of the casing, in mm; _R2 is the radius of the mixing drum (4), in mm; _R1 is the core radius, in mm; the above units need to be converted to be consistent during calculation.

In the present method (S1) and (S3), the temperature is 20 to 200°C, the pressure is 0.1 to 30 MPa, and the core size is 24.5 mm*75 mm.

Application Examples

The method of the present invention is used to actually evaluate the flushing efficiency of the flushing fluid for shale gas wells in western Sichuan, as follows:

The field data required for the experiment came from shale gas wells in western Sichuan. A certain volume of flushing fluid was pumped into the kettle of the device, and the temperature control and pressure programs were edited. The temperature and pressure were raised to the simulated downhole temperature and pressure. The outer cylinder speed was determined by the type of on-site flushing fluid, the actual annular space gap and the displacement. The speed was calculated according to the formula until the flow meter reading remained unchanged. The flushing fluid was pumped back to the flushing fluid tank, and then the drilling fluid was pumped in. The magnetic agitator was started to simulate the circulation of the drilling fluid in the well during drilling, the mud cake formation was simulated, and the water loss in the dynamic filtration process of the drilling fluid was measured. After the water loss was completed, the drilling fluid was pumped back to the drilling fluid tank. At this time, the flushing fluid was pumped in again to simulate the process of flushing the mud cake at the well site. The flushing efficiency of each time period can be calculated by the formula and the real-time flow meter.

First, we kept the displacement of different gas wells at 1.0m ³ /min. The outer cylinder radius and outer cylinder speed corresponding to different annular gaps are shown in Table 1. The flushing efficiency at different temperatures and different annular gaps at different times was measured. The flushing fluid system is the best formula obtained from multiple experiments and is a Newtonian fluid. The basic properties are shown in Table 2. The drilling fluid used in the experiment comes from a shale gas well in western Sichuan. The specific properties are shown in Table 3. The experimental pressure is 20MPa, and the temperature is 60℃, 75℃, and 90℃. The flushing efficiency curves over time are shown in Figures 2, 3, and 4, respectively.

Table 1 - Outer cylinder radius and outer cylinder speed corresponding to different annular gaps

Annular space gap (mm) Radius of mixing drum (mm) External cylinder speed (r/min) 38.1 20.15 370 31.75 18.64 710 25.4 17.20 915 19.05 15.83 854

Table 2 - Optimal flushing solution formula obtained from multiple experiments

Table 3--Basic properties of drilling fluid used in a shale gas well in western Sichuan

Then, we selected a shale gas well as the experimental object. The inner diameter of the wellbore and the outer diameter of the casing are: 215.9mm×139.7mm, the annular space gap is 38.1mm, and the properties of the drilling fluid used are shown in Table 3. The flushing fluid is an emulsified flushing fluid + 0.3% fiber and is a Bingham fluid. Its dynamic shear force is 6Pa, and its plastic viscosity is 18mPa·s. The outer cylinder speed is determined by different displacements as shown in Table 4. The experimental pressure is 20MPa, and the temperature is 60℃, 75℃, and 90℃. The flushing efficiency change curves over time are shown in Figures 5, 6, and 7, respectively.

Table 4 - External cylinder speed corresponding to different displacements

Displacement (m ³ /min) 0.8 1.0 1.2 1.4 External cylinder speed (r/min) 279 353 427 500

In the device of the present invention, the reliability of the experimental data for field application is ensured. The radius _R1 of the artificial core is 12.25 mm. The outer diameter of the mixing drum needs to be determined by the field annular clearance. For example, if the field wellbore × casing is 215.9 × 139.7, then the outer diameter _R2 of the mixing drum calculated by the formula should be 20.15 mm. Further, the outer drum speed can be calculated by the construction displacement. During the experiment, the amount of flushing fluid and drilling fluid added should be as high as possible compared to the artificial core to prevent the centrifugal force from causing poor mud cake formation.

It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (2)

1. The method for detecting the flushing efficiency of the high-temperature high-pressure well cementation two interfaces is characterized by comprising the following steps of: the device comprises a kettle body (1), an artificial rock core (2), a rock core holder (3), a stirring cylinder (4), a magnetic stirrer (5), a metal filter screen and a real-time flowmeter (6); the kettle body (1) is communicated with the flushing fluid bin and the drilling fluid bin, a temperature sensor for detecting the temperature in the kettle body (1) and a pressure sensor for detecting the pressure in the kettle body (1) are arranged on the kettle body, and the temperature sensor and the pressure sensor are connected with a computer through buses; the artificial rock core (2) is detachably fixed at the inner bottom of the kettle body (1) through a rock core holder (3), and the rock core holder (3) is detachably fixed at the inner bottom of the kettle body (1); the stirring barrel (4) is reversely buckled on the artificial rock core (2), and the inner top of the stirring barrel is not contacted with the artificial rock core (2) and is used for simulating drilling fluid filtration to form mud cakes and rotating speeds under different annular gaps; the magnetic stirrer (5) is positioned at the top of the kettle body (1), and a stirring rod of the magnetic stirrer passes through the top of the kettle body (1) and is fixed at the top of the stirring cylinder (4) and is used for driving the stirring cylinder (4) to rotate; the metal filter screen is sleeved on the artificial rock core (2); a liquid discharge hole is formed in the position, where the core holder (3) is arranged, of the kettle body (1), and the liquid discharge hole is communicated with the artificial core (2); the real-time flowmeter (6) is arranged on the liquid discharge hole of the kettle body (1) and is connected with a computer through a bus for measuring the flow of discharged liquid;

The method comprises the following steps:

(S1) selecting corresponding stirring cylinders (4) through the on-site annular gap, installing the corresponding stirring cylinders on a magnetic stirrer (5), and sealing the kettle body (1); then pumping flushing liquid, determining flushing time according to experiment requirements, and adjusting the temperature and pressure of the kettle body (1) to the temperature and pressure required by the experiment; according to different on-site flushing fluid types, different rotating speed formulas are adopted, the rotating speed of the outer cylinder is calculated according to the construction displacement and the annular space, and the initial fluid loss flow Q ₀ of the artificial rock core (2) is measured and recorded through a real-time flowmeter (6);

(S2) pumping drilling fluid into the kettle body (1), heating and boosting, starting the magnetic stirrer (5), simulating drilling fluid to filter out to form mud cakes, and measuring and recording the flow Q ₁ of the drilling fluid through the real-time flowmeter (6);

(S3) pumping drilling fluid out of the kettle body (1), pumping flushing fluid, wherein the set rotating speed, pressure, temperature, flushing fluid consumption and general flushing time parameters of the outer barrel are consistent with those of the flushing fluid pumped in the front, flushing is performed, the water loss flow Q ₂ can be read in real time through a real-time flowmeter (6), and the flushing efficiency is measured, and is:

The rotating speed of the outer cylinder is as follows:

(1) When the flushing fluid is a Bingham fluid, the rotating speed formula of the outer cylinder is as follows:

Wherein lambda is the ratio of the radius of the artificial core (2) to the radius of the rotary outer cylinder; d ₁ is the diameter of the borehole in m; d ₂ is the outer diameter of the sleeve, and the unit is m; w is an annular gap, and the unit is m; q is construction displacement, and the unit is m ³/min; n is the rotation speed of the outer cylinder, and the unit is t/min; τ ₀ is the dynamic shear force of the Bingham fluid in Pa; η is plastic viscosity, and the unit is mPa.s;

(2) When the flushing fluid is power law fluid, the rotating speed formula of the outer cylinder is as follows:

Wherein lambda is the ratio of the radius of the artificial core (2) to the radius of the rotary outer cylinder; d ₁ is the diameter of the borehole in m; d ₂ is the outer diameter of the sleeve, and the unit is m; w is an annular gap, and the unit is m; q is construction displacement, and the unit is m ³/min; n is the rotation speed of the outer cylinder, and the unit is r/min; n _m is the fluidity index of the power law fluid;

(3) When the flushing fluid is Newtonian fluid, namely n _m is 1, the rotating speed formula of the outer cylinder is as follows:

Wherein lambda is the ratio of the radius of the artificial core (2) to the radius of the rotary outer cylinder; d ₁ is the diameter of the borehole in m; d ₂ is the outer diameter of the sleeve, and the unit is m; w is an annular gap, and the unit is m; q is construction displacement, and the unit is m ³/min; n is the rotation speed of the outer cylinder, and the unit is r/min;

The rotary outer cylinder is the stirring cylinder (4); the diameter of the well bore, the outer diameter of the sleeve, the annular clearance and the construction displacement are all construction site parameters;

the radius of the stirring cylinder (4) can be determined by the diameter of the well bore, the outer diameter of the casing and the radius of the core, and the formula is as follows:

Wherein D ₂ is the diameter of the borehole in mm; d ₁ is the outer diameter of the sleeve, and the unit is mm; r ₂ is the radius of the stirring cylinder (4), and the unit is mm; r ₁ is the radius of the core, and the unit is mm; the units need to be converted to be identical in calculation.

2. The method for detecting the flushing efficiency of the high-temperature high-pressure well cementation two interfaces according to claim 1, which is characterized by comprising the following steps: in the method (S1) and (S3), the temperature is 20-200 ℃, the pressure is 0.1-30 MPa, and the core size is 24.5mm 75mm.