Fracturing operation diagnosis method and device based on pressure-time double logarithm judgment, electronic equipment and medium

Abstract

The application discloses a fracturing construction diagnosis method and device based on pressure-time double logarithm judgment, electronic equipment and medium. The method can comprise: calculating rock mechanics parameters and minimum horizontal principal stress of different depth reservoirs, and obtaining the minimum horizontal principal stress distribution of the formation; calculating the fluid friction pressure of the same well section with the same fluid physical property parameters by the resistance coefficient method based on the power-law fluid; calculating the bottom hole net pressure according to the wellhead pressure, static liquid column pressure, fluid friction pressure, near wellbore friction and minimum horizontal principal stress; establishing a double logarithm sequence according to the bottom hole net pressure, identifying the fracture propagation mode, and evaluating the fracturing construction effect. The application can improve the accurate evaluation ability of the fracturing effect on site, and realize dynamic optimization and adjustment of the construction process.

Description

Technical Field

[0001] This invention relates to the field of oil and gas engineering, and more specifically, to a method, apparatus, electronic device, and medium for fracturing construction diagnosis based on pressure-time logarithmic determination. Background Technology

[0002] Hydraulic fracturing technology plays a crucial role in the stimulation of unconventional oil and gas reservoirs. Its core objective is to accurately characterize fracture parameters to assess the effectiveness of the stimulation. Near-wellbore direct diagnostic methods, represented by tracer technology, and far-wellbore direct diagnostic methods, represented by downhole microseismic technology, have been widely applied. However, these technologies are affected by the surface environment and natural fracture zones downhole, leading to limitations in assessment accuracy. Furthermore, cost issues hinder the widespread adoption of these monitoring technologies.

[0003] Fracturing operation curves provide crucial information during the operation process, and significant research has been conducted on them, focusing on curve morphology, absolute pressure values, and parameter evolution. However, in the field of unconventional reservoir stimulation, the operation pressure curves exhibit more complex, multi-stage, and variable characteristics compared to other reservoirs. Research and even diagnostic analysis of these operation curves are still lacking, resulting in fewer application cases.

[0004] To address this challenge, researchers established a bottomhole net pressure calculation model using construction data such as wellhead pressure, pump injection rate, and proppant concentration, and constructed two key parameters: net pressure slope and net pressure exponent. These parameters can dynamically and segmentally describe the mechanical conditions of different fracture propagation behaviors during fracturing and identify the corresponding fracture propagation modes.

[0005] However, current diagnostic methods only consider perforation friction when calculating net pressure, without incorporating small-scale fracturing tests to obtain a more accurate near-wellbore friction expression. Furthermore, existing methods fail to perform differentiated analysis for in-situ stress, resulting in inaccurate fracture behavior analysis under different geological conditions. Additionally, when using net pressure parameters for dynamic segmentation, issues such as low fitting accuracy or even failure to fit properly due to excessive pressure differences can arise. These problems not only weaken the stability of fracturing operation curve diagnosis but also reduce the reliability of fracture pattern identification.

[0006] Therefore, it is necessary to develop a fracturing construction diagnostic method, device, electronic equipment, and medium based on pressure-time double logarithmic determination.

[0007] The information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of this invention, and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art. Summary of the Invention

[0008] This invention proposes a fracturing construction diagnosis method, device, electronic equipment, and medium based on pressure-time double logarithmic determination, which can improve the accuracy of on-site evaluation of fracturing effect and realize dynamic optimization and adjustment of the construction process.

[0009] In a first aspect, embodiments of this disclosure provide a fracturing construction diagnosis method based on pressure-time double logarithmic determination, including:

[0010] Calculate the rock mechanical parameters and minimum horizontal principal stress of reservoirs at different depths to obtain the distribution of minimum horizontal principal stress in the formation.

[0011] The fluid friction pressure of well sections with the same fluid properties is calculated using the power-law fluid drag coefficient method.

[0012] Calculate the bottom hole net pressure based on wellhead pressure, hydrostatic column pressure, fluid friction pressure, near-wellbore friction, and minimum horizontal principal stress.

[0013] A double logarithmic sequence is established based on the bottom hole net pressure to identify fracture propagation patterns and evaluate the effectiveness of fracturing operations.

[0014] Secondly, this disclosure also provides a fracturing construction diagnostic device based on pressure-time double logarithmic determination, comprising:

[0015] The minimum horizontal principal stress calculation module calculates the rock mechanical parameters and minimum horizontal principal stress of reservoirs at different depths, and obtains the distribution of minimum horizontal principal stress in the formation.

[0016] The fluid friction pressure calculation module calculates the fluid friction pressure of well sections with the same fluid properties using the resistance coefficient method based on power-law fluids.

[0017] The bottom hole net pressure calculation module calculates the bottom hole net pressure based on the wellhead pressure, hydrostatic column pressure, fluid friction pressure, near-wellbore friction, and minimum horizontal principal stress.

[0018] The identification module establishes a double logarithmic sequence based on the bottom hole net pressure to identify fracture propagation patterns and evaluate the effectiveness of fracturing operations.

[0019] Thirdly, embodiments of this disclosure also provide an electronic device, the electronic device comprising:

[0020] Memory, which stores executable instructions;

[0021] A processor that executes the executable instructions in the memory to implement the pressure-time double logarithmic determination method for fracturing operations.

[0022] Fourthly, embodiments of this disclosure also provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the aforementioned fracturing construction diagnosis method based on pressure-time double logarithmic determination.

[0023] The methods and apparatus of the present invention have other features and advantages that will be apparent from or will be set forth in detail in the accompanying drawings and following detailed description, which together serve to explain the particular principles of the invention. Attached Figure Description

[0024] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same parts.

[0025] Figure 1 A flowchart illustrating the steps of a fracturing construction diagnostic method based on pressure-time double logarithmic determination according to an embodiment of the present invention is shown.

[0026] Figure 2 A schematic diagram of the triaxial mechanical test results according to an embodiment of the present invention is shown.

[0027] Figure 3 A schematic diagram of a small-scale fracturing test result according to an embodiment of the present invention is shown.

[0028] Figure 4 A schematic diagram showing the fitting results of the near-wellbore friction coefficient according to an embodiment of the present invention is shown.

[0029] Figure 5 A schematic diagram showing the calculation results of a longitudinal geostress profile according to an embodiment of the present invention is provided.

[0030] Figure 6 A schematic diagram showing the calculation results of the near-wellbore friction curve according to an embodiment of the present invention is shown.

[0031] Figure 7 A schematic diagram of the construction curve diagnostic results according to an embodiment of the present invention is shown.

[0032] Figure 8 A block diagram of a fracturing construction diagnostic device based on pressure-time double logarithmic determination according to an embodiment of the present invention is shown.

[0033] Explanation of reference numerals in the attached figures:

[0034] 201. Minimum horizontal principal stress calculation module; 202. Fluid friction pressure calculation module; 203. Bottom hole net pressure calculation module; 204. Identification module. Detailed Implementation

[0035] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0036] To facilitate understanding of the solutions and effects of the embodiments of the present invention, six specific application examples are given below. Those skilled in the art should understand that these examples are merely for the purpose of understanding the present invention, and any specific details therein are not intended to limit the present invention in any way.

[0037] Example 1

[0038] Figure 1 A flowchart illustrating the steps of a fracturing construction diagnostic method based on pressure-time double logarithmic determination according to an embodiment of the present invention is shown.

[0039] like Figure 1 As shown, this fracturing construction diagnosis method based on pressure-time double logarithmic determination includes:

[0040] Step 101: Calculate the rock mechanical parameters and minimum horizontal principal stress of reservoirs at different depths to obtain the distribution of minimum horizontal principal stress in the formation;

[0041] Step 102: Calculate the fluid friction pressure of well sections with the same fluid properties using the resistance coefficient method based on power-law fluids.

[0042] Step 103: Calculate the net pressure at the bottom of the well based on the wellhead pressure, hydrostatic column pressure, fluid friction pressure, near-wellbore friction, and minimum horizontal principal stress.

[0043] Step 104: Establish a double logarithmic sequence based on the bottom hole net pressure, identify fracture propagation patterns, and evaluate the fracturing operation effect.

[0044] In one example, calculating the rock mechanical parameters of reservoirs at different depths includes:

[0045] The dynamic Young's modulus and Poisson's ratio are calculated based on sonic logging data and then converted into static rock Young's modulus and Poisson's ratio.

[0046] The vertical density profile of the formation is obtained based on density logging data, and then the vertical stress is calculated.

[0047] In one example, the minimum horizontal principal stress is calculated according to the generalized Hooke's law:

[0048]

[0049] Where: σ h The minimum horizontal principal stress is given by σ, where h is the formation depth. z Let α be the vertical stress, α be the effective stress coefficient, and p be the vertical stress. p For pore pressure, K h E is the tectonic coefficient in the direction of the minimum horizontal principal stress. s μ is the static Young's modulus. s This is the static Poisson's ratio.

[0050] In one example, the fluid friction pressure of a well section with the same fluid properties is calculated using the power-law fluid drag coefficient method, including:

[0051] Calculate the stability parameters and compare them with preset thresholds to determine the flow state of the sol;

[0052] Calculate the corresponding friction coefficient for different flow states;

[0053] Calculate the fluid friction pressure based on the friction coefficient.

[0054] In one example, the net pressure at the bottom of the well is:

[0055]

[0056] In the formula: P is the net pressure at the bottom of the well, P h P is the wellhead pressure. wf P is the fluid friction pressure. wh ΔP is the hydrostatic pressure. e For near-wellbore friction, σ h This represents the minimum horizontal principal stress.

[0057] In one example, constructing a double logarithmic sequence based on the net bottom-hole pressure includes:

[0058] Based on the net pressure at the bottom of the well, establish a net pressure sequence (P1, P2, P3, ..., P...). N ) and the corresponding time series (t1, t2, t3, ..., t N This is transformed into a double logarithmic sequence, i.e., (logP1, logP2, logP3, ..., logP). N ), (logt1,logt2,logt3,…,logt N ).

[0059] In one example, identifying crack propagation patterns includes:

[0060] ① The following formula can be used to identify the crack propagation pattern as normal crack extension:

[0061]

[0062] ②The crack propagation pattern is identified as a crack network extension using the following formula:

[0063]

[0064] ③ The crack propagation mode is identified as bedding fracture extension by the following formula:

[0065]

[0066] ④ The following formula can be used to identify the crack propagation mode as an obstructed crack extension:

[0067]

[0068] ⑤ The following formula can be used to identify the crack propagation mode as rapid liquid loss:

[0069]

[0070] ⑥ The crack propagation pattern is identified as crack height extension using the following formula:

[0071]

[0072] Wherein: S tnf For tensile strength, σ nf For the normal stress on the crack wall, τ nf The tangential stress on the crack wall

[0073] For cohesion, k nf Let σ be the coefficient of friction. Hmax For the maximum horizontal principal stress, θ nf For the approximation angle, Let σ be the angle of inclination. v For vertical stress, S tbp ΔS represents the tensile strength of the bedding fracture, ΔS represents the stress difference between the reservoir and the upper and lower interlayers, and the subscript nf indicates a natural fracture.

[0074] Specifically, the necessary basic parameters for calculation are collected, including sonic logging data, static rock mechanics parameters, wellbore and tubing parameters, and fracturing parameters. Combined with laboratory rock mechanics tests, and based on relevant empirical formulas, the rock mechanics parameters and minimum horizontal principal stress of reservoirs at different depths are calculated.

[0075] Dynamic Young's modulus and Poisson's ratio can be calculated based on sonic logging data.

[0076]

[0077] Where: μ d For dynamic Poisson's ratio, V pV is the longitudinal wave velocity. s E represents the transverse wave velocity. d ρ is the dynamic Young's modulus, and ρ is the rock density.

[0078] Based on the existing dynamic-static relationship of rock mechanical parameters, the dynamic-static conversion relationship of Young's modulus and Poisson's ratio of rocks is corrected by combining triaxial mechanical test results to obtain the static rock mechanical parameters of reservoir rocks:

[0079] The conversion relationship between the dynamic and static Young's modulus and Poisson's ratio of the reservoir is as follows:

[0080] E s =aE d +b

[0081] μ s =cμ d +d

[0082] In the formula: E s μ is the static Young's modulus. s is the static Poisson ratio, and a, b, c, and d are conversion coefficients.

[0083] Vertical density profiles of formations can be obtained from density logging data, thereby allowing calculation of vertical stress.

[0084]

[0085] Where: σ z Let ρ(h) be the vertical stress at depth h, where h is the formation depth, and ρ(h) be the overall rock density as a function of depth.

[0086] The minimum horizontal principal stress of a reservoir is related not only to the pore fluid pressure and skeletal stress, but also to the tectonic stress on the horizontal plane of the reservoir. Based on the average value of the shut-off pressure and fracture pressure of the completed wells, the tectonic stress coefficient of each layer is calculated, and then, according to the generalized Hooke's law, the following can be obtained:

[0087]

[0088] Where: σ h The minimum horizontal principal stress is given by α, where α is the effective stress coefficient and p is the minimum horizontal principal stress. p For pore pressure, K h This is the tectonic coefficient in the direction of the minimum horizontal principal stress. From this, the distribution of the minimum horizontal principal stress in the strata can be obtained.

[0089] Based on the measured depth variation of the wellbore and the fracturing fluid interface, the friction coefficient method based on power-law fluid is used to calculate the frictional resistance along the well section with the same fluid properties.

[0090] Fracturing fluids are mostly power-law fluids, exhibiting pseudoplasticity and non-Newtonian fluid properties. The stability parameter Z is often used to distinguish the fluid type, expressed as:

[0091] Z=Φ(n)R el

[0092] In the formula, R el For power-law fluids, the Reynolds number is... v is the fracturing fluid velocity inside the tubing, D is the tubing diameter, ρ is the fracturing fluid density, and K... a denoted as σf, where σf is the consistency coefficient of the fracturing fluid as it flows in the wellbore, and n is the rheological index of the fracturing fluid.

[0093] The formulas for calculating the friction coefficient of sols under turbulent conditions only include some empirical correlations under certain pipe size conditions. When Z≤808, the flow of the sol is laminar, and the friction coefficient is:

[0094]

[0095] When Z > 808, the sol flows in a turbulent manner, and the friction coefficient is:

[0096] λ=4f

[0097] In the formula: f is the Fanning coefficient of friction.

[0098] If the annulus injection method is adopted, D is the equivalent diameter of the annulus, D = D2 - D1, where D1 and D2 are the outer diameter of the tubing and the inner diameter of the casing, respectively.

[0099] The frictional pressure of the entire wellbore fluid at time t during construction is calculated using the resistance coefficient method.

[0100]

[0101] In the formula: P wf λ is the fluid friction pressure. i To calculate the friction coefficient of the well section, L i To calculate the well section length, D i To calculate the diameter of the well section, ρ i To calculate the fluid density in the well section, v i To calculate the fluid velocity in the well section.

[0102] Based on the principle of wellbore pressure balance, the net pressure at the bottom of the well is calculated according to the data of wellhead pressure, hydrostatic column pressure, fluid friction pressure, near-wellbore friction and minimum horizontal principal stress.

[0103] Near-wellbore friction mainly includes perforation friction and fracture bending friction. Among them, perforation distribution has a significant impact on perforation friction, and the calculation formula is as follows:

[0104]

[0105] In the formula: P pf Where Q is the orifice friction, D is the pump displacement, and Q is the pump flow rate. ca For perforation density, L is the length of the perforation cluster, d is the orifice diameter, and C is the diameter of the perforation. d The orifice flow coefficient of the horizontal well.

[0106] The fracture bending friction needs to be obtained in conjunction with the results of small-scale fracturing tests. The overall fitting formula for near-wellbore friction is:

[0107] ΔP e =P pf +K nwb Q 0.5

[0108] Where: ΔP e For near-wellbore friction, P pf For the friction of the eyelet, K nwb The coefficient for calculating the bending friction of the crack.

[0109] Combining various friction calculation formulas, the net pressure at the bottom of the well is calculated as follows:

[0110]

[0111] In the formula: P is the net pressure at the bottom of the well, P h P is the wellhead pressure. wh This is the hydrostatic pressure.

[0112] The improved Nolte-Smith double logarithmic curve analysis method was used to identify key feature points of the data curves and evaluate the fracturing operation effect.

[0113] Based on the dynamic segmentation theory of bottom hole net pressure, a net pressure sequence (P1, P2, P3, ..., P) is established according to the bottom hole net pressure. N ) and the corresponding time series (t1, t2, t3, ..., t N This is transformed into a double logarithmic sequence, i.e., (logP1, logP2, logP3, ..., logP). N ), (logt1,logt2,logt3,…,logt N The crack propagation pattern identification criteria are as follows:

[0114] ① The crack extends normally:

[0115]

[0116] ②Extension of the mesh:

[0117]

[0118] ③ Extension of bedding joints:

[0119]

[0120] ④ Crack extension is hindered

[0121]

[0122] ⑤ Rapid liquid filtration

[0123]

[0124] ⑥ Seam height extension

[0125]

[0126] Where: σ nf S is the normal stress on the crack wall. tnf For tensile strength, τ nf τ is the tangential stress on the crack wall. o For cohesion, k nf Let σ be the coefficient of friction. Hmax For the maximum horizontal principal stress, θ nf For the approximation angle, Let σ be the angle of inclination. v For vertical stress, S tbp The tensile strength of the bedding fracture is given by ΔS, where ΔS is the stress difference between the reservoir and the upper and lower interlayers, and the subscript nf indicates a natural fracture.

[0127]

[0128] Example 2

[0129] This invention also provides a fracturing construction diagnostic device based on pressure-time double logarithmic determination, comprising:

[0130] The minimum horizontal principal stress calculation module calculates the rock mechanical parameters and minimum horizontal principal stress of reservoirs at different depths, and obtains the distribution of minimum horizontal principal stress in the formation.

[0131] The fluid friction pressure calculation module calculates the fluid friction pressure of well sections with the same fluid properties using the resistance coefficient method based on power-law fluids.

[0132] The bottom hole net pressure calculation module calculates the bottom hole net pressure based on the wellhead pressure, hydrostatic column pressure, fluid friction pressure, near-wellbore friction, and minimum horizontal principal stress.

[0133] The identification module establishes a double logarithmic sequence based on the bottom hole net pressure to identify fracture propagation patterns and evaluate the effectiveness of fracturing operations.

[0134] In one example, calculating the rock mechanical parameters of reservoirs at different depths includes:

[0135] The dynamic Young's modulus and Poisson's ratio are calculated based on sonic logging data and then converted into static rock Young's modulus and Poisson's ratio.

[0136] The vertical density profile of the formation is obtained based on density logging data, and then the vertical stress is calculated.

[0137] In one example, the minimum horizontal principal stress is calculated according to the generalized Hooke's law:

[0138]

[0139] Where: σ h The minimum horizontal principal stress is given by σ, where h is the formation depth. z Let α be the vertical stress, α be the effective stress coefficient, and p be the vertical stress. p For pore pressure, K h E is the tectonic coefficient in the direction of the minimum horizontal principal stress. s μ is the static Young's modulus. s This is the static Poisson's ratio.

[0140] In one example, the fluid friction pressure of a well section with the same fluid properties is calculated using the power-law fluid drag coefficient method, including:

[0141] Calculate the stability parameters and compare them with preset thresholds to determine the flow state of the sol;

[0142] Calculate the corresponding friction coefficient for different flow states;

[0143] Calculate the fluid friction pressure based on the friction coefficient.

[0144] In one example, the net pressure at the bottom of the well is:

[0145]

[0146] In the formula: P is the net pressure at the bottom of the well, P h P is the wellhead pressure. wf P is the fluid friction pressure. wh ΔP is the hydrostatic pressure. e For near-wellbore friction, σ h This represents the minimum horizontal principal stress.

[0147] In one example, constructing a double logarithmic sequence based on the net bottom-hole pressure includes:

[0148] Based on the net pressure at the bottom of the well, establish a net pressure sequence (P1, P2, P3, ..., P...). N ) and the corresponding time series (t1, t2, t3, ..., t NThis is transformed into a double logarithmic sequence, i.e., (logP1, logP2, logP3, ..., logP). N ), (logt1,logt2,logt3,…,logt N ).

[0149] In one example, identifying crack propagation patterns includes:

[0150] ① The following formula can be used to identify the crack propagation pattern as normal crack extension:

[0151]

[0152] ②The crack propagation pattern is identified as a crack network extension using the following formula:

[0153]

[0154] ③ The crack propagation mode is identified as bedding fracture extension by the following formula:

[0155]

[0156] ④ The following formula can be used to identify the crack propagation mode as an obstructed crack extension:

[0157]

[0158] ⑤ The following formula can be used to identify the crack propagation mode as rapid liquid loss:

[0159]

[0160] ⑥ The crack propagation pattern is identified as crack height extension using the following formula:

[0161]

[0162] Wherein: S tnf For tensile strength, σ nf For the normal stress on the crack wall, τ nf The tangential stress on the crack wall τ o For cohesion, k nf Let σ be the coefficient of friction. Hmax For the maximum horizontal principal stress, θ nf For the approximation angle, Let σ be the angle of inclination. v For vertical stress, S tbp ΔS represents the tensile strength of the bedding fracture, ΔS represents the stress difference between the reservoir and the upper and lower interlayers, and the subscript nf indicates a natural fracture.

[0163] Specifically, the necessary basic parameters for calculation are collected, including sonic logging data, static rock mechanics parameters, wellbore and tubing parameters, and fracturing parameters. Combined with laboratory rock mechanics tests, and based on relevant empirical formulas, the rock mechanics parameters and minimum horizontal principal stress of reservoirs at different depths are calculated.

[0164] Dynamic Young's modulus and Poisson's ratio can be calculated based on sonic logging data.

[0165]

[0166] Where: μ d For dynamic Poisson's ratio, V p V is the longitudinal wave velocity. s E represents the transverse wave velocity. d ρ is the dynamic Young's modulus, and ρ is the rock density.

[0167] Based on the existing dynamic-static relationship of rock mechanical parameters, the dynamic-static conversion relationship of Young's modulus and Poisson's ratio of rocks is corrected by combining triaxial mechanical test results to obtain the static rock mechanical parameters of reservoir rocks:

[0168] The conversion relationship between the dynamic and static Young's modulus and Poisson's ratio of the reservoir is as follows:

[0169] E s =aE d +b

[0170] μ s =cμ d +d

[0171] In the formula: E s μ is the static Young's modulus. s is the static Poisson ratio, and a, b, c, and d are conversion coefficients.

[0172] Vertical density profiles of formations can be obtained from density logging data, thereby allowing calculation of vertical stress.

[0173]

[0174] Where: σ z Let ρ(h) be the vertical stress at depth h, where h is the formation depth, and ρ(h) be the overall rock density as a function of depth.

[0175] The minimum horizontal principal stress of a reservoir is related not only to the pore fluid pressure and skeletal stress, but also to the tectonic stress on the horizontal plane of the reservoir. Based on the average value of the shut-off pressure and fracture pressure of the completed wells, the tectonic stress coefficient of each layer is calculated, and then, according to the generalized Hooke's law, the following can be obtained:

[0176]

[0177] Where: σ h The minimum horizontal principal stress is given by α, where α is the effective stress coefficient and p is the minimum horizontal principal stress. p For pore pressure, K h This is the tectonic coefficient in the direction of the minimum horizontal principal stress. From this, the distribution of the minimum horizontal principal stress in the strata can be obtained.

[0178] Based on the measured depth variation of the wellbore and the fracturing fluid interface, the friction coefficient method based on power-law fluid is used to calculate the frictional resistance along the well section with the same fluid properties.

[0179] Fracturing fluids are mostly power-law fluids, exhibiting pseudoplasticity and non-Newtonian fluid properties. The stability parameter Z is often used to distinguish the fluid type, expressed as:

[0180] Z=Φ(n)R el

[0181] In the formula, R el For power-law fluids, the Reynolds number is... v is the fracturing fluid velocity inside the tubing, D is the tubing diameter, ρ is the fracturing fluid density, and K... a denoted as σf, where σf is the consistency coefficient of the fracturing fluid as it flows in the wellbore, and n is the rheological index of the fracturing fluid.

[0182] The formulas for calculating the friction coefficient of sols under turbulent conditions only include some empirical correlations under certain pipe size conditions. When Z≤808, the flow of the sol is laminar, and the friction coefficient is:

[0183]

[0184] When Z > 808, the sol flows in a turbulent manner, and the friction coefficient is:

[0185] λ=4f

[0186] In the formula: f is the Fanning coefficient of friction.

[0187] If the annulus injection method is adopted, D is the equivalent diameter of the annulus, D = D2 - D1, where D1 and D2 are the outer diameter of the tubing and the inner diameter of the casing, respectively.

[0188] The frictional pressure of the entire wellbore fluid at time t during construction is calculated using the resistance coefficient method.

[0189]

[0190] In the formula: P wf λ is the fluid friction pressure. i To calculate the friction coefficient of the well section, L i To calculate the well section length, D iTo calculate the diameter of the well section, ρ i To calculate the fluid density in the well section, v i To calculate the fluid velocity in the well section.

[0191] Based on the principle of wellbore pressure balance, the net pressure at the bottom of the well is calculated according to the data of wellhead pressure, hydrostatic column pressure, fluid friction pressure, near-wellbore friction and minimum horizontal principal stress.

[0192] Near-wellbore friction mainly includes perforation friction and fracture bending friction. Among them, perforation distribution has a significant impact on perforation friction, and the calculation formula is as follows:

[0193]

[0194] In the formula: P pf Where Q is the orifice friction, D is the pump displacement, and Q is the pump flow rate. ca For perforation density, L is the length of the perforation cluster, d is the orifice diameter, and C is the diameter of the perforation. d The orifice flow coefficient of the horizontal well.

[0195] The fracture bending friction needs to be obtained in conjunction with the results of small-scale fracturing tests. The overall fitting formula for near-wellbore friction is:

[0196] ΔP e =P pf +K nwb Q 0.5

[0197] Where: ΔP e For near-wellbore friction, P pf For the friction of the eyelet, K nwb The coefficient for calculating the bending friction of the crack.

[0198] Combining various friction calculation formulas, the net pressure at the bottom of the well is calculated as follows:

[0199]

[0200] In the formula: P is the net pressure at the bottom of the well, P h P is the wellhead pressure. wh This is the hydrostatic pressure.

[0201] The improved Nolte-Smith double logarithmic curve analysis method was used to identify key feature points of the data curves and evaluate the fracturing operation effect.

[0202] Based on the dynamic segmentation theory of bottom hole net pressure, a net pressure sequence (P1, P2, P3, ..., P) is established according to the bottom hole net pressure. N ) and the corresponding time series (t1, t2, t3, ..., t N This is transformed into a double logarithmic sequence, i.e., (logP1, logP2, logP3, ..., logP).N ), (logt1,logt2,logt3,…,logt N The crack propagation pattern identification criteria are as follows:

[0203] ① The crack extends normally:

[0204]

[0205] ②Extension of the mesh:

[0206]

[0207] ③ Extension of bedding joints:

[0208]

[0209] ④ Crack extension is hindered

[0210]

[0211] ⑤ Rapid liquid filtration

[0212]

[0213] ⑥ Seam height extension

[0214]

[0215] Where: σ nf S is the normal stress on the crack wall. tnf For tensile strength, τ nf τ is the tangential stress on the crack wall. o For cohesion, k nf Let σ be the coefficient of friction. Hmax For the maximum horizontal principal stress, θ nf For the approximation angle, Let σ be the angle of inclination. v For vertical stress, S tbp The tensile strength of the bedding fracture is given by ΔS, where ΔS is the stress difference between the reservoir and the upper and lower interlayers, and the subscript nf indicates a natural fracture.

[0216]

[0217] Example 3

[0218] The basic parameters for calculating geostress are shown in Table 1.

[0219] Table 1. Basic parameters for geostress calculation

[0220]

[0221] The basic parameters for calculating frictional resistance along the path are shown in Table 2.

[0222] Table 2 Basic parameters for calculating friction resistance

[0223]

[0224] The basic parameters for construction pressure curve diagnosis are shown in Table 3.

[0225] Table 3 Basic Parameters for Diagnostic Use of Construction Pressure Curve

[0226]

[0227]

[0228] Figure 2 A schematic diagram of the triaxial mechanical test results according to an embodiment of the present invention is shown.

[0229] Figure 3 A schematic diagram showing the calculation results of a longitudinal geostress profile according to an embodiment of the present invention is provided.

[0230] Calculations were performed based on the fundamental parameters in Tables 1-3. Triaxial mechanical experiments were conducted, and the results are as follows: Figure 2 As shown, mechanical parameters such as Young's modulus and Poisson's ratio were obtained, and the triaxial in-situ stress of the reservoir was calculated. The calculation results of the longitudinal in-situ stress profile are shown below. Figure 3 As shown, the calculated minimum horizontal principal stress is 64.69 MPa.

[0231] Figure 4 A schematic diagram of a small-scale fracturing test result according to an embodiment of the present invention is shown.

[0232] Figure 5 A schematic diagram showing the fitting results of the near-wellbore friction coefficient according to an embodiment of the present invention is shown.

[0233] Figure 6 A schematic diagram showing the calculation results of the near-wellbore friction curve according to an embodiment of the present invention is shown.

[0234] Combination such as Figure 4 The results of small-scale fracturing tests shown are at 12, 10, 8, 6, 4, and 2 m. 3 At a displacement of [value] / min, the corresponding wellhead pressures were 95.29, 89.49, 85.36, 80.74, 76.35, and 71.55 MPa, respectively; the instantaneous pump shutdown pressure was 65.4 MPa; the near-wellbore friction coefficient was fitted using the least squares method, as shown below. Figure 5 As shown, the expression for calculating near-wellbore friction can be obtained as: ΔP e =0.00449×Q 2+4.5116×Q 0.5 R 2 =0.994; then the calculated result of the near-wellbore friction curve is as follows Figure 6 As shown.

[0235] Figure 7 A schematic diagram of the construction curve diagnostic results according to an embodiment of the present invention is shown.

[0236] like Figure 7 As shown, after diagnosing the fracturing construction curve of the example layer, it was found that the time for normal fracture extension was 13.21%, the time for fracture network extension was 25.94%, the time for fracture height extension was 35.85%, and the total effective fracture extension time accounted for 75.00%. The fracture extension was hindered, and the total time for abnormal fracture extension accounted for 25.00%. The pressure curve fluctuated significantly, with frequent abnormal changes, and the fracture network communication was restricted.

[0237] Example 4

[0238] Figure 8 A block diagram of a fracturing construction diagnostic device based on pressure-time double logarithmic determination according to an embodiment of the present invention is shown.

[0239] like Figure 8 As shown, the fracturing construction diagnostic device based on pressure-time double logarithmic determination includes:

[0240] Minimum horizontal principal stress calculation module 201 calculates the rock mechanical parameters and minimum horizontal principal stress of reservoirs at different depths, and obtains the distribution of minimum horizontal principal stress of the formation.

[0241] The fluid friction pressure calculation module 202 calculates the fluid friction pressure of well sections with the same fluid properties using the resistance coefficient method based on power-law fluids.

[0242] The bottom hole net pressure calculation module 203 calculates the bottom hole net pressure based on the wellhead pressure, hydrostatic column pressure, fluid friction pressure, near-wellbore friction, and minimum horizontal principal stress.

[0243] The identification module 204 establishes a double logarithmic sequence based on the bottom hole net pressure to identify fracture propagation patterns and evaluate the fracturing operation effect.

[0244] In one example, calculating the rock mechanical parameters of reservoirs at different depths includes:

[0245] The dynamic Young's modulus and Poisson's ratio are calculated based on sonic logging data and then converted into static rock Young's modulus and Poisson's ratio.

[0246] The vertical density profile of the formation is obtained based on density logging data, and then the vertical stress is calculated.

[0247] In one example, the minimum horizontal principal stress is calculated according to the generalized Hooke's law:

[0248]

[0249] Where: σ h The minimum horizontal principal stress is given by σ, where h is the formation depth. z Let α be the vertical stress, α be the effective stress coefficient, and p be the vertical stress. p For pore pressure, K h E is the tectonic coefficient in the direction of the minimum horizontal principal stress. s μ is the static Young's modulus. s This is the static Poisson's ratio.

[0250] In one example, the fluid friction pressure of a well section with the same fluid properties is calculated using the power-law fluid drag coefficient method, including:

[0251] Calculate the stability parameters and compare them with preset thresholds to determine the flow state of the sol;

[0252] Calculate the corresponding friction coefficient for different flow states;

[0253] Calculate the fluid friction pressure based on the friction coefficient.

[0254] In one example, the net pressure at the bottom of the well is:

[0255]

[0256] In the formula: P is the net pressure at the bottom of the well, P h P is the wellhead pressure. wf P is the fluid friction pressure. wh ΔP is the hydrostatic pressure. e For near-wellbore friction, σ h This represents the minimum horizontal principal stress.

[0257] In one example, constructing a double logarithmic sequence based on the net bottom-hole pressure includes:

[0258] Based on the net pressure at the bottom of the well, establish a net pressure sequence (P1, P2, P3, ..., P...). N ) and the corresponding time series (t1, t2, t3, ..., t N This is transformed into a double logarithmic sequence, i.e., (logP1, logP2, logP3, ..., logP). N ), (logt1,logt2,logt3,…,logt N ).

[0259] In one example, identifying crack propagation patterns includes:

[0260] ① The following formula can be used to identify the crack propagation pattern as normal crack extension:

[0261]

[0262] ②The crack propagation pattern is identified as a crack network extension using the following formula:

[0263]

[0264] ③ The crack propagation mode is identified as bedding fracture extension by the following formula:

[0265]

[0266] ④ The following formula can be used to identify the crack propagation mode as an obstructed crack extension:

[0267]

[0268] ⑤ The following formula can be used to identify the crack propagation mode as rapid liquid loss:

[0269]

[0270] ⑥ The crack propagation pattern is identified as crack height extension using the following formula:

[0271]

[0272] Wherein: S tnf For tensile strength, σ nf For the normal stress on the crack wall, τ nf The tangential stress on the crack wall τ o For cohesion, k nf Let σ be the coefficient of friction. Hmax For the maximum horizontal principal stress, θ nf For the approximation angle, Let σ be the angle of inclination. v For vertical stress, S tbp ΔS represents the tensile strength of the bedding fracture, ΔS represents the stress difference between the reservoir and the upper and lower interlayers, and the subscript nf indicates a natural fracture.

[0273] Example 5

[0274] This disclosure provides an electronic device, comprising: a memory storing executable instructions; and a processor executing the executable instructions in the memory to implement the aforementioned fracturing construction diagnosis method based on pressure-time double logarithmic determination.

[0275] An electronic device according to an embodiment of the present disclosure includes a memory and a processor.

[0276] This memory is used to store non-transitory computer-readable instructions. Specifically, the memory may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may, for example, include random access memory (RAM) and / or cache memory. The non-volatile memory may, for example, include read-only memory (ROM), hard disk, flash memory, etc.

[0277] The processor may be a central processing unit (CPU) or other form of processing unit with data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions. In one embodiment of this disclosure, the processor is used to execute computer-readable instructions stored in the memory.

[0278] Those skilled in the art will understand that, in order to solve the technical problem of how to achieve a good user experience, this embodiment may also include well-known structures such as communication buses and interfaces, and these well-known structures should also be included within the protection scope of this disclosure.

[0279] For a detailed description of this embodiment, please refer to the corresponding descriptions in the foregoing embodiments, which will not be repeated here.

[0280] Example 6

[0281] This disclosure provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the aforementioned fracturing construction diagnosis method based on pressure-time double logarithmic determination.

[0282] A computer-readable storage medium according to embodiments of the present disclosure stores non-transitory computer-readable instructions. When these non-transitory computer-readable instructions are executed by a processor, all or part of the steps of the methods described in the foregoing embodiments of the present disclosure are performed.

[0283] The aforementioned computer-readable storage media include, but are not limited to: optical storage media (e.g., CD-ROM and DVD), magneto-optical storage media (e.g., MO), magnetic storage media (e.g., magnetic tape or portable hard drive), media with built-in rewritable non-volatile memory (e.g., memory card), and media with built-in ROM (e.g., ROM cartridge).

[0284] Those skilled in the art should understand that the above description of the embodiments of the present invention is only intended to illustrate the beneficial effects of the embodiments of the present invention, and is not intended to limit the embodiments of the present invention to any of the examples given.

[0285] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A fracturing construction diagnosis method based on pressure-time double logarithmic determination, characterized in that, include: Calculate the rock mechanical parameters and minimum horizontal principal stress of reservoirs at different depths to obtain the distribution of minimum horizontal principal stress in the formation. The fluid friction pressure of well sections with the same fluid properties is calculated using the resistance coefficient method based on power-law fluids. Calculate the bottom hole net pressure based on wellhead pressure, hydrostatic column pressure, fluid friction pressure, near-wellbore friction, and minimum horizontal principal stress. A double logarithmic sequence is established based on the bottom hole net pressure to identify fracture propagation patterns and evaluate the effectiveness of fracturing operations.

2. The fracturing construction diagnosis method based on pressure-time double logarithmic determination according to claim 1, wherein, The calculation of rock mechanical parameters for reservoirs at different depths includes: The dynamic Young's modulus and Poisson's ratio are calculated based on sonic logging data and then converted into static rock Young's modulus and Poisson's ratio. The vertical density profile of the formation is obtained based on density logging data, and then the vertical stress is calculated.

3. The fracturing construction diagnosis method based on pressure-time double logarithmic determination according to claim 2, wherein, Calculate the minimum horizontal principal stress according to the generalized Hooke's law: In the formula: σ h The minimum horizontal principal stress is given by σ, where h is the formation depth. z Let α be the vertical stress, α be the effective stress coefficient, and p be the vertical stress. p For pore pressure, K h E is the tectonic coefficient in the direction of the minimum horizontal principal stress. s μ is the static Young's modulus. s This is the static Poisson's ratio.

4. The fracturing construction diagnosis method based on pressure-time double logarithmic determination according to claim 1, wherein, The fluid friction pressure in well sections with the same fluid properties is calculated using the power-law fluid drag coefficient method, including: Calculate the stability parameters and compare them with preset thresholds to determine the flow state of the sol; Calculate the corresponding friction coefficient for different flow states; Calculate the fluid friction pressure based on the friction coefficient.

5. The fracturing construction diagnosis method based on pressure-time double logarithmic determination according to claim 1, wherein, The net pressure at the bottom of the well is: In the formula: P is the net pressure at the bottom of the well, P h P is the wellhead pressure. wf P is the fluid friction pressure. wh ΔP is the hydrostatic pressure. e For near-wellbore friction, σ h This represents the minimum horizontal principal stress.

6. The fracturing construction diagnosis method based on pressure-time double logarithmic determination according to claim 1, wherein, Establishing a double logarithmic sequence based on the bottom-hole net pressure includes: Based on the net pressure at the bottom of the well, establish a net pressure sequence (P1, P2, P3, ..., P...). N ) and the corresponding time series (t1, t2, t3, ..., t N This is transformed into a double logarithmic sequence, i.e., (logP1, logP2, logP3, ..., logP). N ), (logt1,logt2,logt3,…,logt N ).

7. The fracturing construction diagnosis method based on pressure-time double logarithmic determination according to claim 6, wherein, Identifying crack propagation patterns includes: ① The crack propagation mode is identified as normal crack extension by the following formula: ②The crack propagation mode is identified as a crack network extension by the following formula: ③ The crack propagation mode is identified as bedding fracture extension by the following formula: ④ The crack propagation mode is identified as crack extension obstruction by the following formula: ⑤ The crack propagation mode is identified as rapid liquid loss using the following formula: ⑥ The crack propagation mode is identified as crack height extension by the following formula: Wherein: S tnf For tensile strength, σ nf For the normal stress on the crack wall, τ nf The tangential stress on the crack wall, τ o For cohesion, k nf Let σ be the coefficient of friction. Hmax For the maximum horizontal principal stress, θ nf For the approximation angle, Let σ be the angle of inclination. v For vertical stress, S tbp ΔS represents the tensile strength of the bedding fracture, ΔS represents the stress difference between the reservoir and the upper and lower interlayers, and the subscript nf indicates a natural fracture.

8. A fracturing construction diagnostic device based on pressure-time double logarithmic determination, characterized in that, include: The minimum horizontal principal stress calculation module calculates the rock mechanical parameters and minimum horizontal principal stress of reservoirs at different depths, and obtains the distribution of minimum horizontal principal stress in the formation. The fluid friction pressure calculation module calculates the fluid friction pressure of well sections with the same fluid properties using the resistance coefficient method based on power-law fluids. The bottom hole net pressure calculation module calculates the bottom hole net pressure based on the wellhead pressure, hydrostatic column pressure, fluid friction pressure, near-wellbore friction, and minimum horizontal principal stress. The identification module establishes a double logarithmic sequence based on the bottom hole net pressure to identify fracture propagation patterns and evaluate the effectiveness of fracturing operations.

9. An electronic device, characterized in that, The electronic device includes: Memory, which stores executable instructions; A processor that executes the executable instructions in the memory to implement the fracturing construction diagnosis method based on pressure-time double logarithmic determination as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the fracturing construction diagnosis method based on pressure-time double logarithmic determination as described in any one of claims 1-7.

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