A method and medium for calculating in-situ strength while drilling based on well-seismic fusion information

Abstract

The application relates to a method for calculating in-situ strength while drilling based on well-seismic fusion information, which comprises the following steps: step 1, constructing an initial mechanical parameter calculation model of a formation to be drilled according to well data and seismic data; step 2, obtaining geological mechanics basic parameters of the formation to be drilled in front of a drill bit according to the initial mechanical parameter calculation model; step 3, calculating geological mechanics strength parameters according to the geological mechanics basic parameters; step 4, calculating formation in-situ strength according to the mechanical strength parameters; and step 5, correcting the formation in-situ strength in combination with the well data to obtain in-situ strength while drilling under different working conditions. The application combines seismic data and drilling engineering data to establish a quantitative relationship between rock mechanics parameters and drilling parameters, and realizes rapid acquisition of in-situ strength while drilling under different working conditions in combination with Mohr-Coulomb strength criterion and experimental analysis correction.

Description

Technical Field

[0001] This invention relates to the field of oil and gas development technology, specifically to a method and medium for in-situ strength calculation while drilling based on well seismic fusion information. Background Technology

[0002] With the continuous advancement of oil exploration, the accurate assessment and real-time monitoring of underground formation mechanical parameters have become crucial and urgent. In traditional drilling operations, to ensure the safety and efficiency of drilling, engineers typically rely on conventional methods to estimate formation mechanical parameters.

[0003] However, due to the complexity and heterogeneity of underground strata, traditional methods have certain limitations in providing highly accurate mechanical parameters.

[0004] For example, in-situ formation strength is crucial for assessing formation rock-breaking efficiency. In-situ strength during drilling is also an important evaluation indicator for analyzing drilling pressure. The accuracy of calculations for these indicators needs to be improved. Summary of the Invention

[0005] To address the aforementioned problems, the purpose of this invention is to provide a method and medium for calculating in-situ strength while drilling based on well-seismic fusion information. By combining seismic data with drilling engineering data, a quantitative relationship between rock mechanical parameters and drilling parameters is established. Combined with the Mohr-Coulomb strength criterion and experimental analysis correction, the in-situ strength while drilling under different working conditions can be rapidly obtained.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] Firstly, this application provides a method for in-situ strength calculation while drilling based on well-seismic fusion information, which includes:

[0008] Step 1: Based on the drilled well data and seismic data, construct an initial mechanical parameter calculation model for the formation to be drilled;

[0009] Step 2: Based on the initial mechanical parameter calculation model, obtain the basic geomechanical parameters of the formation to be drilled in front of the drill bit;

[0010] Step 3: Calculate the geomechanical strength parameters based on the aforementioned basic geomechanical parameters;

[0011] Step 4: Calculate the in-situ strength of the formation based on the mechanical strength parameters;

[0012] Step 5: Based on the in-situ strength of the formation, and combined with the drilled data, the in-situ strength under different working conditions is corrected to obtain the in-situ strength while drilling.

[0013] In one implementation of this application, step 1 includes:

[0014] Step 11: Obtain logging data from the drilled wells, fill in any missing logging data, and obtain the drilled well data.

[0015] Step 12: Obtain seismic data of the area to be drilled, extract seismic wavelets from the seismic data, and calibrate the synthetic seismic record obtained from the well logging data with the well-side seismic record.

[0016] Step 13: Using the wave impedance inversion method, the initial velocity and density data of the formation to be drilled are obtained, and the initial mechanical parameter calculation model is obtained.

[0017] In one implementation of this application, step 2 includes:

[0018] Step 21: Perform rock physics analysis on the formation to be drilled, compare the analysis results with seismic data, and update the initial reservoir parameters of the formation to be drilled using drilling parameters;

[0019] Step 22: Update the initial mechanical parameter calculation model based on the logging-while-drilling data;

[0020] Step 23: Calculate the basic geomechanical parameters of the formation to be drilled in front of the drill bit based on the updated initial mechanical parameter calculation model.

[0021] In one implementation of this application, step 3 includes:

[0022] Step 31: Calculate the uniaxial compressive strength of the rock using the basic geomechanical parameters of the stratum to be drilled in front of the drill bit.

[0023] Step 32: Calculate the elastic modulus using the basic geomechanical parameters of the formation to be drilled in front of the drill bit;

[0024] Step 33: Calculate the Poisson's ratio of the rock using the basic geomechanical parameters of the stratum to be drilled in front of the drill bit;

[0025] Step 34: Calculate the internal friction angle and cohesion of the rock using the basic geomechanical parameters of the stratum to be drilled in front of the drill bit;

[0026] Step 35: Calculate the tensile strength of the rock using the basic geomechanical parameters of the stratum to be drilled in front of the drill bit.

[0027] In one implementation of this application, step 4 includes:

[0028] Step 41: Establish an in-situ strength model of the formation;

[0029] Step 42, correct the in-situ strength model of the formation;

[0030] Step 43: Calculate the in-situ strength of the un-drilled strata using the basic geomechanical parameters of the strata to be drilled ahead of the drill bit and the modified in-situ strength model of the strata.

[0031] In one implementation of this application, in step 41, the in-situ formation strength model is described as follows:

[0032]

[0033] In the formula, σ1 is the initial in-situ strength of the strata, σ3 is the confining pressure on the strata rocks, and σ c It is the uniaxial compressive strength of the rock strata, and φ is the internal friction angle.

[0034] In one implementation of this application, in step 42, an in-situ strength test of the strata in the study area is conducted using an indoor triaxial experiment to correct the in-situ strength model of the strata.

[0035] The revised in-situ strength model of the formation is expressed as follows:

[0036]

[0037] In the formula, α is the formation strength correction factor.

[0038] In one implementation of this application, step 5 includes:

[0039] Step 51: Calculate the in-situ strength while drilling based on the in-situ strength model of the formation and the different working conditions in front of the drill bit.

[0040] Step 52: Analyze the drilling pressure based on the calculated in-situ strength under different working conditions, and use it as a drilling evaluation index.

[0041] In one implementation of this application, the formula for calculating the in-situ strength while drilling is expressed as follows:

[0042]

[0043] In the formula, σ cw ρ is the in-situ strength while drilling; g is the acceleration due to gravity; and h is the drilling depth.

[0044] Secondly, this application provides a computer-readable storage medium storing a computer program, which, when executed by a processor, controls the computer device where the processor is located to implement the in-situ strength calculation method based on well seismic fusion information as described in the first aspect.

[0045] The present invention has the following advantages due to the adoption of the above technical solutions:

[0046] This invention constructs an initial mechanical parameter calculation model for the formation to be drilled using drilled well data and seismic data. Based on this model, the basic geomechanical parameters of the formation ahead of the drill bit are obtained. Furthermore, based on these parameters, geomechanical strength parameters are calculated. Then, based on these strength parameters, the in-situ strength of the formation is calculated. Finally, based on this in-situ strength and combined with drilled well data, corrections are made to obtain the in-situ strength under different operating conditions. This invention provides a high-precision method for calculating in-situ strength under drilling conditions compared to traditional techniques, offering technical support for oil and gas engineering. Attached Figure Description

[0047] Figure 1 This is a flowchart of the method for rapid in-situ strength evaluation while drilling, which integrates well and seismic testing.

[0048] Figure 2 This is a graph showing the results of completing missing well logging data;

[0049] Figure 3 It is the initial regional P-wave velocity volume diagram obtained after well seismic calibration;

[0050] Figure 4 It is an updated P-wave velocity volume diagram obtained through drilling and seismic calibration during drilling;

[0051] Figure 5 This is a comparison chart of the improved prediction during drilling and the original prediction;

[0052] Figure 6 This is a diagram showing the results of rock geomechanical parameters during drilling;

[0053] Figure 7 It is the in-situ strength map in front of the drill bit that is updated during drilling;

[0054] Figure 8 It is an in-situ strength diagram of the drill bit front under different drilling fluid density conditions. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0056] To address the issue of insufficient accuracy in calculating in-situ strength while drilling in existing technologies, this application provides a method for calculating in-situ strength while drilling based on well-seismic fusion information. The method includes: Step 1, constructing an initial mechanical parameter calculation model for the formation to be drilled based on drilled well data and seismic data; Step 2, obtaining the basic geomechanical parameters of the formation ahead of the drill bit based on the initial mechanical parameter calculation model; Step 3, calculating the geomechanical strength parameters based on the basic geomechanical parameters; Step 4, calculating the in-situ strength of the formation based on the mechanical strength parameters; Step 5, correcting the in-situ strength of the formation based on the drilled well data to obtain the in-situ strength while drilling under different operating conditions. This technical solution, by combining seismic data with drilling engineering data, establishes a quantitative relationship between rock mechanical parameters and drilling parameters, and combines the Mohr-Coulomb strength criterion and experimental analysis for correction, enables rapid acquisition of in-situ strength while drilling under different operating conditions.

[0057] The experimental system and method of this application will be further described in detail below with reference to the accompanying drawings.

[0058] like Figure 1 As shown, this invention provides a method for in-situ strength calculation while drilling based on well seismic fusion information, including:

[0059] Step 1: Based on the drilled well data and seismic data, construct an initial mechanical parameter calculation model for the formation to be drilled;

[0060] Step 2: Based on the initial mechanical parameter calculation model, obtain the basic geomechanical parameters of the formation to be drilled in front of the drill bit;

[0061] Step 3: Calculate the geomechanical strength parameters based on the aforementioned basic geomechanical parameters;

[0062] Step 4: Calculate the in-situ strength of the formation based on the mechanical strength parameters;

[0063] Step 5: Based on the in-situ strength of the formation, and combined with the drilled data, the in-situ strength under different working conditions is corrected to obtain the in-situ strength while drilling.

[0064] Specifically, step 1 includes:

[0065] Step 11: For the drilled well logging data, complete any missing logging data. The completed data is illustrated below. Figure 2 ;

[0066] Step 12: For the seismic data of the study area, extract the seismic wavelet from the seismic data and calibrate the synthetic seismic record obtained from the well logging data and the seismic record from the well track.

[0067] Step 13: Based on the wave impedance inversion method, obtain the initial velocity and density data of the formation to be drilled, and obtain the initial mechanical model, such as... Figure 3 The meaning is as shown.

[0068] Step 2 includes:

[0069] Step 21: Based on the results of rock physics analysis, compare them with actual seismic data, and use drilling parameters to update the predicted initial reservoir parameters such as lithology, porosity, and even fluids.

[0070] Step 22: Update the established initial mechanical model based on the results of the logging-while-drilling data analysis, such as... Figure 4 Indication;

[0071] Step 23 obtains the relevant parameters of the initial mechanical model of the un-drilled formation, including velocity, density, depth, and wavelet. These fundamental mechanical parameters have high accuracy. See [link to relevant documentation]. Figure 5 .

[0072] like Figure 6 Step 3 includes:

[0073] Step 31: Using the high-precision mechanical data of the un-drilled strata ahead of the drill bit obtained in Step 2, the uniaxial compressive strength of the rock is obtained, which is the ultimate strength of the rock specimen under uniaxial pressure at failure. Numerically, it is equal to the maximum axial stress at failure, and is usually denoted by σ. c express:

[0074]

[0075] In the formula, P is the load applied at the time of failure, called the failure load; A is the original cross-sectional area.

[0076] Step 32: Using the high-precision mechanical data of the un-drilled formation ahead of the drill bit obtained in Step 2, the elastic modulus is obtained:

[0077]

[0078] In the formula, E is the slope of the stress-strain curve, that is, the rate of change of stress relative to strain under uniaxial stress. Δσ z , Δε z These are the increments of axial stress and strain, respectively.

[0079] Step 33: Using the high-precision mechanical data of the un-drilled formation ahead of the drill bit obtained in Step 2, the Poisson's ratio υ of the rock is obtained. The Poisson's ratio υ is the radial strain ε of the rock under uniaxial compression. r (i.e., transverse strain) and axial strain ε z The ratio of (i.e., longitudinal strain), that is, the ratio of lateral elongation to longitudinal shortening:

[0080]

[0081] Step 34: Using the high-precision mechanical data of the un-drilled strata ahead of the drill bit obtained in Step 2, the internal friction angle φ and cohesion C of the rock are obtained. o The relationship can be expressed as:

[0082]

[0083] In the formula: M = a1 - b1·C0, (a, b, a1, b1 are constants related to the rock).

[0084] Step 35: Using the high-precision mechanical data of the un-drilled strata ahead of the drill bit obtained in Step 2, the tensile strength St of the rock is obtained, and calculated using the following formula:

[0085]

[0086] Among them: E d V is the dynamic elastic modulus; cl The content of clay; K is taken as 8-15.

[0087] like Figure 7 Step 4 includes:

[0088] Step 41: Establish an in-situ formation strength model using the Mohr-Coulomb strength criterion.

[0089]

[0090] In the formula, σ1 is the initial in-situ strength of the strata, σ3 is the confining pressure on the strata rocks, and σ c It is the uniaxial compressive strength of the rock strata, and φ is the internal friction angle;

[0091] Step 42: Conduct in-situ physical model tests on the formation strength of the study area using indoor triaxial experiments. The indoor experiments are used to correct the in-situ formation strength model from Step 41.

[0092]

[0093] In the formula, α is the formation strength correction factor.

[0094] Step 43: Using the high-precision mechanical basis data of the un-drilled strata ahead of the drill bit obtained in Step 3 and the in-situ strength correction model of the strata obtained in Step 42, perform in-situ strength prediction of the un-drilled strata.

[0095] Step 5 includes:

[0096] Step 51: Using the in-situ strength model of the un-drilled formation ahead of the drill bit obtained in Step 4, and combining it with the design of different working conditions ahead of the drill bit, calculate the in-situ strength σ while drilling. cw,

[0097]

[0098] In the formula, σ cw ρ is the in-situ strength while drilling; g is the acceleration due to gravity; and h is the drilling depth.

[0099] Step 52: Using the calculation results from step 51, analyze the drilling pressure as a drilling evaluation index, such as... Figure 8 The meaning is as shown.

[0100] In another aspect of this application, this application provides a computer-readable storage medium storing a computer program, which, when executed by a processor, controls the computer device where the processor is located to implement the in-situ strength calculation method based on well seismic fusion information as described in the first aspect.

[0101] In the several embodiments provided by this invention, it should be understood that the disclosed methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0102] The integrated units implemented as software functional units described above can be stored in a computer-readable storage medium. These software functional units, stored in a storage medium, include several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute some steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0103] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for in-situ strength calculation while drilling based on well-seismic fusion information, characterized in that, The method includes: Step 1: Based on the drilled well data and seismic data, construct an initial mechanical parameter calculation model for the formation to be drilled; Step 2: Based on the initial mechanical parameter calculation model, obtain the basic geomechanical parameters of the formation to be drilled in front of the drill bit; Step 3: Calculate the geomechanical strength parameters based on the aforementioned basic geomechanical parameters; Step 4: Calculate the in-situ strength of the formation based on the mechanical strength parameters; Step 5: Based on the in-situ formation strength and combined with the drilled well data, correct the in-situ strength under different operating conditions to obtain the in-situ strength while drilling, including: Step 51: Calculate the in-situ strength while drilling based on the in-situ strength model of the formation and the different working conditions in front of the drill bit. Step 52: Analyze the drilling pressure based on the calculated in-situ strength under different working conditions, and use it as a drilling evaluation index. The formula for calculating the in-situ strength while drilling is as follows: In the formula, σ cw ρ is the in-situ strength while drilling; ρ is the drilling fluid density; g is the gravitational acceleration; h is the drilling depth; σ3 is the confining pressure on the formation rock; σ c φ is the uniaxial compressive strength of the rock formation, φ is the internal friction angle, and α is the formation strength correction factor.

2. The in-situ strength calculation method while drilling based on well-seismic fusion information according to claim 1, characterized in that, Step 1 includes: Step 11: Obtain logging data from the drilled wells, fill in any missing logging data, and obtain the drilled well data. Step 12: Obtain seismic data of the area to be drilled, extract seismic wavelets from the seismic data, and calibrate the synthetic seismic record obtained from the well logging data with the well-side seismic record. Step 13: Using the wave impedance inversion method, the initial velocity and density data of the formation to be drilled are obtained, and the initial mechanical parameter calculation model is obtained.

3. The in-situ strength calculation method while drilling based on well-seismic fusion information according to claim 1, characterized in that, Step 2 includes: Step 21: Perform rock physics analysis on the formation to be drilled, compare the analysis results with seismic data, and update the initial reservoir parameters of the formation to be drilled using drilling parameters; Step 22: Update the initial mechanical parameter calculation model based on the logging-while-drilling data; Step 23: Calculate the basic geomechanical parameters of the formation to be drilled in front of the drill bit based on the updated initial mechanical parameter calculation model.

4. The in-situ strength calculation method based on well-seismic fusion information according to claim 3, characterized in that, Step 3 includes: Step 31: Calculate the uniaxial compressive strength of the rock using the basic geomechanical parameters of the stratum to be drilled in front of the drill bit. Step 32: Calculate the elastic modulus using the basic geomechanical parameters of the formation to be drilled in front of the drill bit; Step 33: Calculate the Poisson's ratio of the rock using the basic geomechanical parameters of the stratum to be drilled in front of the drill bit; Step 34: Calculate the internal friction angle and cohesion of the rock using the basic geomechanical parameters of the stratum to be drilled in front of the drill bit; Step 35: Calculate the tensile strength of the rock using the basic geomechanical parameters of the stratum to be drilled in front of the drill bit.

5. The in-situ strength calculation method while drilling based on well seismic fusion information according to claim 4, characterized in that, Step 4 includes: Step 41: Establish an in-situ strength model of the formation; Step 42, correct the in-situ strength model of the formation; Step 43: Calculate the in-situ strength of the un-drilled strata using the basic geomechanical parameters of the strata to be drilled ahead of the drill bit and the modified in-situ strength model of the strata.

6. The in-situ strength calculation method while drilling based on well-seismic fusion information according to claim 5, characterized in that, In step 41, the in-situ formation strength model is described as follows: In the formula, σ1 is the initial in-situ strength of the strata, σ3 is the confining pressure on the strata rocks, and σ c It is the uniaxial compressive strength of the rock strata, and φ is the internal friction angle.

7. The in-situ strength calculation method while drilling based on well seismic fusion information according to claim 6, characterized in that, In step 42, an indoor triaxial experiment is used to conduct a physical model test on the in-situ strength of the strata in the study area, and the in-situ strength model of the strata is corrected. The revised in-situ strength model of the formation is expressed as follows: In the formula, α is the formation strength correction factor.

8. A computer-readable storage medium, characterized in that, The system contains a computer program that, when executed by a processor, controls the computer device containing the processor to implement the in-situ strength calculation method based on well seismic fusion information as described in any one of claims 1 to 7.

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