High-frequency pressure real-time monitoring fracturing sand plugging method

Abstract

The invention relates to the technical field of gas exploitation, in particular to a high-frequency pressure real-time monitoring fracturing sand plugging method which is characterized by comprising the following steps: establishing a fracturing well test model at a cloud end; according to the well testing model of the fractured well, a well testing fitting typical curve of the fractured well is calculated; converting the pressure of the pump stopping wellhead into the pressure in well testing analysis; skin and crack lengths are obtained through curve fitting of pump stopping pressure; and the fracturing sand plugging condition is judged according to the obtained skin and crack length. And the real-time monitoring of the fracturing sand plugging condition is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of gas extraction, and particularly to a method for real-time monitoring of high-frequency pressure for fracturing sand plugging. Background Art

[0002] The method for monitoring fracturing sand plugging is a series of technical means used in the field of resource extraction such as petroleum to understand and control the situation related to sand plugging during the fracturing construction process. In the fracturing operation of oil and gas wells, proppants play a key role in opening the fractures and forming a diversion channel to increase the oil and gas production. However, sometimes there are sand plugging problems such as unreasonable distribution of proppants in the fractures and premature blockage of the channels, which affect the fracturing effect.

[0003] The existing methods for monitoring fracturing sand plugging mainly include microseismic monitoring method. During the fracturing process, the rock fracture will generate tiny seismic waves, and a series of geophones are arranged around the well or on the ground to receive these microseismic signals. According to the information such as the source location and intensity of the signals, the extension direction, length and width of the fractures are analyzed, but the fluctuation signals cannot infer the migration and distribution state of the proppants in the fractures and cannot judge sand plugging; distributed optical fiber monitoring method, a device with optical fiber is placed around the wellbore or lowered into the well along with the tubing, and the physical property changes such as the strain and temperature of the optical fiber are used to reflect the changes in the external environment, so as to judge the liquid injection position, fracture length and height of the fracturing fluid, etc., and it also cannot judge sand plugging; tracer monitoring method, different types of tracers are injected into the formation together with the fracturing fluid in each fracturing stage, and during the post-fracture flowback period, the flowback situation of the tracers is detected at the wellhead or the surrounding monitoring wells to judge the liquid production ratio of each cluster in the multi-stage fracturing of horizontal wells. Since the liquid production ratio of each cluster is obtained by inverting the concentration of the tracers, the concentration ratios of various tracers have nothing to do with sand plugging.

[0004] Unconventional oil and gas development requires the use of large-scale volume fracturing technology. First, the fracturing fluid is used to fracture the formation, and then the proppants are used to support the fractures to prevent the fractures from closing. To obtain better oil and gas development effects, a certain amount of fracturing fluid and proppants must be injected into the formation. For example, unconventional oil and gas fracturing requires tens of thousands of cubic meters of water and thousands of tons of sand. If sand plugging occurs during the fracturing process, on the one hand, it prevents the fracturing fluid from entering the formation, making the fractures unable to continue to expand and extend. On the other hand, the proppants cannot enter the fractures to support the fractures, or cause the fractures to close. Most importantly, the occurrence of sand plugging will cause the wellbore pressure to rise rapidly, causing serious damage to the wellbore structure.

[0005] Therefore, there is an urgent need for a method that can quickly monitor the situation of fracturing sand plugging to solve the problems existing in the above fracturing technology. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to propose a method for real-time monitoring of high-frequency pressure sand plugging in fracturing, so as to solve the problem of quickly and accurately obtaining skin data for real-time monitoring of sand plugging in fracturing.

[0007] Based on the above purpose, the present invention provides a method for real-time monitoring of high-frequency pressure sand plugging in fracturing, including:

[0008] Establish a well testing model for the fractured well in the cloud;

[0009] According to the well testing model of the fractured well, calculate the well testing fitting typical curve;

[0010] Convert the shut-in wellhead pressure into the pressure in well testing analysis;

[0011] Obtain the skin and fracture length through curve fitting of the shut-in pressure;

[0012] Judge the sand plugging situation in fracturing according to the obtained skin and fracture length

[0013] Optionally, the conversion of the shut-in wellhead pressure into the pressure in well testing analysis includes:

[0014] Use unstructured PEBI grid numerical simulation to calculate the pressure drawdown chart during fracturing shut-in;

[0015] Use the material balance time:

[0016]

[0017] Use Duhamel's principle to recalculate the pressure:

[0018]

[0019] Optionally, obtaining the skin and fracture length through curve fitting of the shut-in pressure includes:

[0020] Calculate the permeability through Darcy's law;

[0021] Use the typical curve chart fitting method for inversion.

[0022] Optionally, the inversion using the typical curve chart fitting method includes:

[0023] Bottom hole pressure P WD (t Dxf ) is expressed as:

[0024]

[0025] In the formula:

[0026] is the dimensionless time;

[0027] is the dimensionless bottom-hole pressure;

[0028] is the exponential integral function;

[0029] is the error function;

[0030] k is the absolute formation permeability, with the unit of (μm 2 );

[0031] B is the fluid volume coefficient;

[0032] q is the daily injection volume of the fracturing fluid, with the unit of (m 3 / d);

[0033] C t is the comprehensive compressibility, with the unit of (1 / MPa);

[0034] x f is the half-length of the hydraulic fracturing crack, with the unit of (m);

[0035] h is the effective formation thickness, with the unit of (m);

[0036] μ is the fluid viscosity, with the unit of (mPa·s);

[0037] φ is the formation porosity;

[0038] In the Laplace space, there is:

[0039]

[0040] where: u is the Laplace variable; K0 and K1 are the second-kind Bessel functions of order 0 and 1 with imaginary argument;

[0041] is the Struve function of order 0 modified;

[0042] is the Struve function of order 1 modified;

[0043] is the Γ function;

[0044] According to C D and S, by using the solution in the form of bottom-hole pressure convolution, the expression of the bottom-hole pressure in the Laplace space is obtained:

[0045]

[0046] where: is the bottom-hole pressure in the Laplace space without considering C D, the bottom-hole pressure of the S transient source, is given by Equation (1.2); S is the skin factor; is the dimensionless wellbore storage constant.

[0047] Optionally, according to C D and S, by using the solution in the form of bottom-hole pressure convolution, the expression of the bottom-hole pressure in the Laplace space includes:

[0048] Performing numerical Laplace inversion on the expression of the bottom-hole pressure in the Laplace space to obtain the numerical solutions of the bottom-hole pressure and its derivative at a given time;

[0049] According to the obtained numerical solutions of the bottom-hole pressure and its derivative at a given time, plot the double logarithmic curves of the bottom-hole pressure and its derivative, i.e., lg P WD ~lgt Dxf and lgP' WD ~lgt Dxf of the combined curve (P' WD = dP WD / d(ln t Dxf ))).

[0050] Optionally, the plotting of the double logarithmic curves of the bottom-hole pressure and its derivative according to the obtained numerical solutions of the bottom-hole pressure and its derivative at a given time includes:

[0051] According to C Dxf = 0.01, S m = 1.0 for the typical curve, analyze the components of the typical curve of the uniform flow type vertical fracture in an infinite formation:

[0052] The first part is the wellbore storage section, where the double logarithmic curves of the pressure and its derivative coincide and are a straight line segment of -45°;

[0053] The second part is the transition from the wellbore storage section to the linear flow section, where the pressure derivative appears as a peak, and the height of the peak is affected by the value of S m The larger the S m the higher this peak;

[0054] The third part is the linear flow section, where the pressure and its derivative curves are approximately parallel, and the slope of their straight line segments is both 1 / 2;

[0055] The fourth part is the formation radial flow section. From the perspective of the entire formation, the vertical fracture well is equivalent to a straight well, thus forming a radial flow. Plot the semi-logarithmic graph of the bottom-hole pressure, representing the bottom-hole pressure at this time with semi-logarithmic time; at this time, the double logarithmic pressure derivative curve is a horizontal line with a value of 0.5;

[0056] Obtain the formation and fracture parameters according to the fitting of the double logarithmic pressure and its derivative.

[0057] Optionally, the formation and fracture parameters obtained by fitting the double logarithm pressure and derivative include:

[0058] The formation permeability can be obtained from the pressure fitting value PM:

[0059]

[0060] The fracture half-length and wellbore skin are obtained from the time fitting value TM:

[0061]

[0062] From C Dxf The wellbore storage constant can be obtained:

[0063]

[0064] From S m The total skin and additional pressure drop can be obtained:

[0065] S t = S w + S m (1.7);

[0066] ΔP S = S t / PM(1.8).

[0067] The beneficial effects of the present invention: The present invention provides a method for real-time monitoring of high-frequency pressure for proppant plugging during fracturing. Since proppant plugging is the accumulation of a large amount of proppant around the wellbore and fractures during fracturing, which hinders fluid flow. The existence of proppant plugging makes it difficult for the fracturing fluid to enter the formation, and this resistance is the additional pressure drop in oil and gas field exploration and development. And the fluid flow resistance can be characterized by pressure, so the high-frequency pressure is used to monitor the pressure change in real time, and the proppant plugging is judged through pressure analysis.

[0068] The increase in the skin value or the additional pressure drop value is an important feature of proppant plugging. By obtaining the skin technology to judge the proppant plugging situation, the fracturing process can be changed as soon as possible. By increasing the displacement fluid during fracturing, the proppant can be squeezed into the fractures to solve the proppant plugging problem. The earlier the proppant plugging is discovered, the lower the fracturing construction cost. Description of the Drawings

[0069] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the implementation examples or the description of the prior art. Obviously, the drawings in the following description are only those of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0070] Figure 1Flow chart of a method for real-time monitoring of high-frequency pressure for fracturing sand plugging according to an embodiment of the present invention;

[0071] Figure 2 Double logarithmic typical curve graph of a method for real-time monitoring of high-frequency pressure for fracturing sand plugging according to an embodiment of the present invention;

[0072] Figure 3 Semi-logarithmic graph of bottom hole pressure of a method for real-time monitoring of high-frequency pressure for fracturing sand plugging according to an embodiment of the present invention;

[0073] Figure 4 Fracturing construction curve graph of an application example of a method for real-time monitoring of high-frequency pressure for fracturing sand plugging according to an embodiment of the present invention. Detailed implementation manners

[0074] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with specific embodiments.

[0075] It should be noted that unless otherwise defined, the technical terms or scientific terms used in the present invention should be the ordinary meanings understood by those with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. The terms such as "connection" or "coupling" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left", "right" are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0076] As Figure 1 shown, a specific embodiment of the present invention provides a method for real-time monitoring of high-frequency pressure for fracturing sand plugging, including:

[0077] S101, establishing a well testing model for a fracturing well in the cloud;

[0078] S201, calculating a well testing fitting typical curve for the fracturing well according to the well testing model for the fracturing well, and calculating and plotting it into a double logarithmic graph of pressure and derivative;

[0079] S301, converting the wellhead pressure after pump shutdown into the pressure in well testing analysis;

[0080] S401, obtaining the skin and fracture length through curve fitting of the pressure after pump shutdown;

[0081] S501, judging the fracturing sand plugging situation according to the obtained skin value.

[0082] There are three characteristics in summarizing the sand plugging in fracturing:

[0083] (1) The water hammer wave signal is weak when the pump stops. This is because if a large amount of proppant (solid particles) accumulates in the wellbore, water and proppant are two substances with different densities, and the water hammer wave is absorbed by the proppant when propagating in the pipeline;

[0084] (2) The wellhead pressure increases during fracturing. Due to the occurrence of sand plugging during fracturing, the resistance of the fracturing fluid entering the formation increases, which leads to the increase of the wellhead pressure;

[0085] (3) The derivative curve in the shut-in pressure shows a high skin characteristic. In well test analysis, the skin is used to represent the pollution near the wellbore. When a large amount of sand plugs at the fracture inlet, a large additional pressure drop will be generated, which is reflected as a high skin characteristic on the bottom hole pressure and derivative curve. Since the skin can be obtained through well test and there is an industry standard in the petroleum industry to use the skin to represent pollution. Therefore, the shut-in pressure analysis method can be used to analyze the shut-in pressure data to obtain the skin, so as to realize the monitoring of the sand plugging situation in fracturing.

[0086] In some optional specific embodiments, the conversion of the shut-in wellhead pressure into the pressure in well test analysis includes:

[0087] During the fracturing construction of deep coal seam gas, large displacement is used for fracturing. Near the wellbore, it is mainly fracturing fluid. After the pump stops, the free gas in the coal seam can be not considered. Therefore, the pressure drawdown chart during fracturing shut-in can be calculated, that is, the double logarithmic chart of pressure and derivative.

[0088] Due to the large displacement during fracturing, such as the displacement of 20m 3 / Min, when converted to daily production, it is 28800m 3 / D. The data after fracturing shut-in cannot be directly analyzed by well test software. Due to the large displacement during fracturing, the material balance time is used:

[0089]

[0090] In the material balance time, the production in the denominator can be equivalent to the daily production, such as 100m 3 / D, which makes the material balance time very large. For example, the displacement is 20m 3 / Min (i.e., the daily production of 28800m 3 / D), the time increases by 288 times, that is, the pump is stopped for 40 minutes, and the actual material balance time is 192 hours. For large-scale volume fracturing, although the pump is stopped for 40 minutes, it is equivalent to a well test analysis time of 192 hours. Therefore, as long as the liquid injection volume of each section can be determined, the reliability of the interpretation result can be guaranteed by analyzing the pump shut-in pressure data. Since the displacement changes with time during fracturing, the Duhamel principle is used to recalculate the pressure:

[0091]

[0092] In some optional specific embodiments, the obtaining of the skin and fracture length by curve fitting of the pump shut-in pressure includes:

[0093] Darcy's law gives the relationship between pressure and seepage velocity. When the fluid flow rate, pressure and viscosity are known, the permeability can be obtained through Darcy's law. Since the inversion involves multiple parameters such as fracture half-length, fracture conductivity, permeability, and average pressure, a typical curve chart fitting method must be used for inversion. The following gives the inversion theory and method.

[0094] In an infinite formation, without considering C D and S, for a uniformly flowing vertical fracture with a single production rate, the bottom-hole pressure P WD (t Dxf ) can be expressed as

[0095]

[0096] In the formula

[0097] —Dimensionless time;

[0098] —Dimensionless bottom-hole pressure;

[0099] —Exponential integral function;

[0100] —Error function;

[0101] k—Absolute formation permeability, (μm 2 );

[0102] B—Fluid volume coefficient;

[0103] q—Daily injection volume of fracturing fluid, (m 3 / d);

[0104] C t —Comprehensive compressibility, (1 / MPa);

[0105] x f—Half-length of hydraulic fracturing fracture, (m);

[0106] h—Effective thickness of formation, (m);

[0107] μ—Fluid viscosity, (mPa·s);

[0108] φ—Formation porosity;

[0109] In Laplace space, there is

[0110]

[0111] Wherein

[0112] u—Laplace variable;

[0113] K0, K1—Modified Bessel functions of the second kind of order 0 and order 1;

[0114] —Modified Struve function of order 0;

[0115] —Modified Struve function of order 1;

[0116] —Gamma function;

[0117] The establishment of the well test model for the fracturing well in the cloud includes: After considering C D and S, using the solution in the form of bottom hole pressure convolution, the expression of the bottom hole pressure in Laplace space is obtained:

[0118]

[0119] Wherein

[0120] —Bottom hole pressure of the instantaneous source without considering C D and S in Laplace space, given by Equation (1.2);

[0121] S—Skin factor;

[0122] —Dimensionless wellbore storage constant;

[0123] Performing numerical Laplace inversion on Equation (1.3), the numerical solutions of the bottom hole pressure and its derivative at a given time can be obtained, and then plotted as a double logarithmic curve of the bottom hole pressure and its derivative, namely lg P WD ~lg t Dxf and lg P' WD ~lg t Dxf The combined curve of (P' WD = dPWD / d(ln t Dxf ). Obviously, the parameters in this type of typical curve are C Dxf and S m There are two of them, and S m Since it is the skin of a vertical fracture, S m ≥0.

[0124] Figure 2 is a typical curve when C Dxf = 0.01 and S m = 1.0. It can be seen from the figure that the typical curve of a uniform flow rate vertical fracture in an infinite formation consists of four parts.

[0125] The first part is the wellbore storage section. In this part, due to the influence of wellbore storage, the double logarithmic curves of pressure and its derivative coincide and are a straight line segment with an angle of -45°;

[0126] The second part is the transition from the wellbore storage section to the linear flow section. In this part, the pressure derivative shows a peak, and the height of the peak is affected by the value of S m The larger the S m , the higher this peak;

[0127] The third part is the linear flow section. In this part, the pressure and its derivative curves are approximately parallel, and the slope of the straight line segment is 1 / 2. This is mainly caused by the linear flow in the vertical fracture;

[0128] The fourth part is the formation radial flow section. In this part, from the perspective of the entire formation, the vertical fracture well is equivalent to a straight well, thus forming a radial flow. The bottom hole pressure at this time can be expressed in terms of semi-logarithmic time, as Figure 3 shown. And the double logarithmic pressure derivative curve is a horizontal line with a value of 0.5.

[0129] Although the typical curve of a uniform flow rate vertical fracture well in an infinite formation theoretically consists of four parts, the actual measured data of the bottom hole pressure of a uniform flow rate vertical fracture often only shows the third and fourth parts. Because in most cases, the bottom hole pressure of a vertical fracture well can only exhibit the wellbore storage effect when the time is very small, and this time is often not measurable.

[0130] The formation and fracture parameters are obtained by fitting the double logarithmic pressure and its derivative. The fitting process is as follows:

[0131] The formation permeability is obtained from the pressure fitting value PM:

[0132]

[0133] According to the fracturing well test model, calculating the fitting typical curve of the fracturing well test includes: obtaining the fracture half-length and wellbore skin from the time fitting value TM:

[0134]

[0135] The fracturing well test model can be established in the cloud through formula (1.5).

[0136]

[0137] From C Dxf the wellbore storage constant is obtained:

[0138]

[0139] From S m the total skin and additional pressure drop are obtained:

[0140] S t = S w + S m (1.8);

[0141] ΔP S = S t / PM(1.9).

[0142] In some optional specific embodiments, judging the fracturing sand plugging situation according to the obtained skin value includes: if the skin is between [0 - 0.1), there is no sand plug; [0.1 - 0.3), slight sand plug; [0.3 - 0.6], sand plug; the skin is greater than 0.6, serious sand plug.

[0143] As Figure 4 shown, it is a specific application example of a method for real-time monitoring of high-frequency pressure fracturing sand plugging in the present invention, and specifically obtained:

[0144] The permeability K of the SRV area is calculated as 3.891 md by formula (1.4); the fracture length Xf is calculated as 11.06 m by formula (1.5), and the skin is 7.2.

[0145] Those of ordinary skill in the art should understand that: the discussion of any above embodiment is only exemplary, and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples; under the idea of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above, and they are not provided in detail for the sake of brevity.

[0146] The present invention aims to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for real-time monitoring of high-frequency pressure for fracturing sand plugging, characterized in that, Including: Establish a well test model for fractured wells in the cloud; Calculate the typical curve for well test fitting of fractured wells according to the well test model for fractured wells; Convert the shut-in wellhead pressure into the pressure in well test analysis; Obtain the skin and fracture length through curve fitting of the shut-in pressure; Judge the sand plugging situation of fracturing according to the obtained skin and fracture length.

2. The real-time high-frequency pressure monitoring method for fracturing sand plugging according to claim 1, characterized in that The conversion of the shut-in wellhead pressure into the pressure in well test analysis includes: Use unstructured PEBI grid numerical simulation to calculate the pressure drawdown chart during the shut-in of fracturing pumps; Adopt the material balance time; Recalculate the pressure using Duhamel's principle; 3. The real-time high-frequency pressure monitoring method for fracturing sand plugging according to claim 1, characterized in that, Obtaining the skin and fracture length through curve fitting of the shut-in pressure includes: Calculate the permeability through Darcy's law; Invert using the typical curve chart fitting method.

4. A high-frequency pressure real-time monitoring method for fracturing sand plugging according to claim 3, characterized in that, The inversion using the typical curve chart fitting method includes: Bottom hole pressure P WD (t Dxf ) is expressed as: In the formula: is the dimensionless time; is the dimensionless bottom-hole pressure; is the exponential integral function; is the error function; k is the absolute permeability of the formation, with the unit of (μm 2 ); B is the fluid volume coefficient; q is the daily injection volume of the fracturing fluid, with the unit of (m 3 / d); C t is the comprehensive compressibility factor, with the unit of (1 / MPa); x f is the half-length of the hydraulic fracturing crack, with the unit of (m); h is the effective formation thickness, with the unit of (m); μ is the fluid viscosity, with the unit of (mPa·s); φ is the formation porosity; In the Laplace space, there is: Where: u is the Laplace variable; K0, K1 are the second-kind zero-order and first-order Bessel functions of imaginary argument; Struve function of order zero correction; is the Struve function of the first order modified; is the Γ function; According to C D and S, using the solution in the form of bottom-hole pressure convolution, the expression of the bottom-hole pressure in the Laplace space is obtained: Wherein: is the bottom-hole pressure of the Laplace space without considering C D , S is the instantaneous source bottom-hole pressure, given by Equation (1.2); S is the skin factor; is the dimensionless wellbore storage constant.

5. A high-frequency pressure real-time monitoring method for fracturing sand plugging according to claim 4, characterized in that, Said according to C D and S, using the solution in the form of bottom-hole pressure convolution, the expression of bottom-hole pressure in Laplace space is obtained, including: Perform numerical Laplace inversion on the expression of the bottom-hole pressure in the Laplace space to obtain the numerical solutions of the bottom-hole pressure and its derivative at a given time; According to the numerical solutions of the bottom-hole pressure and its derivative at a given time, plot the double logarithmic curves of the bottom-hole pressure and its derivative, namely lgP WD ~lgt Dxf and lgP′ WD ~lgt Dxf combined curve (P′ WD = dP WD / d(lnt Dxf )) 6. The real-time high-frequency pressure monitoring method for fracturing sand plugging according to claim 5, characterized in that The plotting of the double logarithmic curve of the bottom-hole pressure and its derivative according to the obtained numerical solutions of the bottom-hole pressure and its derivative at a given time includes: According to C Dxf = 0.01, S m = 1.0, analyze the components of the typical curve of a vertically fractured well with a uniform flow rate in an infinite formation: In the first part, the wellbore storage section, the double logarithmic curves of the pressure and its derivative coincide and are a straight line segment of -45°; Part II is the transition from the wellbore storage section to the linear flow section, where the pressure derivative shows a peak, and the height of the peak is affected by the value of S m value, and the larger the value of S m , the higher this peak is; In the third part, it is the linear flow section, the pressure and its derivative curves are approximately parallel, and the slope of their straight line segments is 1 / 2; In the fourth part, it is the formation radial flow section. From the perspective of the entire formation, the vertical fractured well is equivalent to a vertical well, thus forming a radial flow. Plot the semi-logarithmic graph of the bottom-hole pressure, with the semi-logarithmic time representing the bottom-hole pressure at this time; at this time, the double logarithmic pressure derivative curve is a horizontal line with a value of 0.5; Obtain the formation and fracture parameters through fitting of the double logarithmic pressure and its derivative.

7. A high-frequency pressure real-time monitoring method for fracturing sand plugging according to claim 6, characterized in that, The obtaining of the formation and fracture parameters through fitting of the double logarithmic pressure and its derivative includes: The formation permeability can be obtained from the pressure fitting value PM; The half-length of the fracture and the wellbore skin are obtained from the time fitting value TM; From C Dxf the wellbore storage constant can be obtained: From S m the total skin and additional pressure drop can be obtained: S t = S w + S m (1.8); ΔP S = S t / PM(1.9).

8. A high-frequency pressure real-time monitoring method for fracturing sand plugging according to claim 1, characterized in that The obtaining of the formation and fracture parameters through fitting of the double logarithmic pressure and its derivative includes: The judgment of the sand plugging situation of fracturing according to the obtained skin value includes: If the skin is between [0 - 0.1), there is no sand plug; [0.1 - 0.3), slight sand plug; [0.3 - 0.6], sand plug; when the skin is greater than 0.6, serious sand plug.

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