Method and system for establishing whole-well-section well-seismic relation based on drilling index Dx

Abstract

The invention discloses a method and a system for establishing a whole-well-section well-to-seismic relationship based on a drilling index Dx, and provides a method for establishing comprehensive parameters of a power exponent of a product of a sound wave speed and the drilling index Dx along with depth change by utilizing the generality that the formation sound wave speed and the drilling index Dx both reflect the change of a regional formation compaction trend along with the depth change. An empirical formula of the buried depth of the stratum, the drilling index Dx and the sound wave speed is obtained through regression analysis, and the relation between the sound wave speed and the time depth fitted with the drilling index Dx of the buried depth of the stratum is calculated according to the empirical formula; and calculating wave impedance and a reflection coefficient based on the acoustic velocity fitted by the drilling index Dx and a Gardner formula, and performing deconvolution calculation on the reflection coefficient and the selected wavelet to generate a synthetic seismic record. According to the method and system, full-well-section well-seismic calibration with the drilling parameters as the data source can be achieved under the condition that logging sound waves and density data do not exist or are lacked.

Description

Background Art

[0002] Synthetic seismic records are seismic records (seismic traces) converted from acoustic well logging or vertical seismic profile data through artificial synthesis. They are usually seismic trace models generated by convolution of well logging or vertical seismic logging (VSP) and seismic wavelets. The geological information obtained along the wellbore is associated with the regional seismic information through the time-depth relationship, laying the foundation for the comprehensive interpretation of seismic data and the prediction of the distribution of geological sediments on the plane.

[0003] The general process of synthetic seismic record production is: the reflection coefficient is calculated from the acoustic wave and density logging curve, and the reflection coefficient is convolved with the extracted seismic wavelet to obtain the initial synthetic seismic record. The initial synthetic seismic record is corrected according to the more accurate velocity field, and then matched and adjusted with the seismic trace beside the well to finally obtain the synthetic seismic record. The process can be summarized as follows: according to the logging data, the rock density and velocity information at the selected well location are extracted; the rock wave impedance is calculated according to the density and velocity data to obtain the reflection coefficient sequence; the wavelet type, main frequency, sampling rate and other parameters are selected to determine the appropriate seismic wavelet; the seismic wavelet is convolved with the reflection coefficient sequence to obtain the synthetic seismic record.

[0004] In the regional geological research work using geological information obtained after drilling, the combination of well and seismic data is an indispensable means. For wells without acoustic or VSP seismic logging data, the time-depth relationship of neighboring wells is usually directly used for the well; or other types of logging data of the well, such as resistivity, are used to simulate acoustic data, and then the time-depth relationship of the well is fictitious.

[0005] Limited by geophysical logging technology, logging costs and complex downhole geological conditions, the number of wells that choose to implement acoustic or VSP seismic logging during or after drilling is limited. At the same time, even if formation acoustic logging is implemented in many wells, the measurement interval is limited to the target layer. Limited by these objective conditions, many wells that have been drilled lack acoustic or VSP logging data, which affects the establishment of the time-depth relationship between wells and seismic, and cannot achieve full-well section well and seismic calibration; even if parameters such as logging resistivity can be used to fit acoustic waves, they are still limited by many factors such as logging intervals and the rationality of parameter applicability. Summary of the invention

[0006] The technical problem to be solved by the present invention is to construct a quantitative formula for fitting the acoustic wave velocity with the drilling index Dx for wells or well sections without acoustic logging data, and apply it to establish a time-depth relationship and produce synthetic seismic records.

[0007] In order to solve the above technical problems, the present invention provides a well seismic calibration method using a drilling index Dx to synthesize seismic records and calculate the time-depth relationship.

[0008] The present invention can be implemented by the following technical scheme: A method for establishing a well-seismic relationship of the entire well section based on a drilling index Dx, comprising the following steps:

[0009] Step S1: obtaining the drilling speed, total drill bit speed, drilling pressure and drill bit size of the drilling machine using the drilling parameters as the data source during the drilling process, and calculating the dimensionless parameter drilling index Dx indicating the rock skeleton strength;

[0010] Step S2: Acquire the data of the well section with acoustic velocity and density logging items, make synthetic seismic records based on the logging data, determine the travel time of each formation stratification point on the seismic profile by well seismic calibration, and obtain the time-depth relationship curve calculated based on the logging data by regression;

[0011] Step S3: selecting a well section with logging acoustic wave data, constructing a comprehensive parameter whose power exponent of the product of logging acoustic wave velocity and drilling index Dx increases with depth, and obtaining a relationship between the burial depth of the formation and the drilling index Dx and logging acoustic wave velocity through regression analysis;

[0012] Step S4: The relationship between the burial depth of the formation, the drilling index Dx and the acoustic wave velocity obtained by regression analysis is linked to the comprehensive index relationship constructed by the logging acoustic wave velocity, the drilling index Dx and the depth, and the acoustic wave velocity DT in the relationship is regarded as an unknown quantity, so as to obtain a relationship for calculating the acoustic wave velocity Dx_Sim from the drilling index Dx;

[0013] Step S5: Calculate the time-depth relationship based on the acoustic wave velocity Dx_Sim calculated based on the drilling index Dx, substitute the acoustic wave velocity Dx_Sim fitted by the drilling index Dx into the Gardner empirical formula to calculate the rock density Dx_den, substitute the acoustic wave velocity Dx_Sim and rock density Dx_den fitted by Dx into the wave impedance calculation formula to obtain the wave impedance value Dx_AI, calculate the reflection coefficient according to the set sampling interval, select a suitable sub-wave, perform deconvolution calculation of the reflection coefficient and the wavelet product, and obtain a synthetic seismic record based on the drilling index Dx;

[0014] Step S6: Calculate the fitted acoustic wave velocity Dx_Sim from the drilling index Dx of the entire well section, and calculate the rock density using the Gardner empirical formula, and finally obtain the wave impedance Dx_AI of the entire well section based on the drilling index Dx, completing the production of synthetic seismic records of the entire well section.

[0015] Furthermore, step S3 also includes a step of comparing the time-depth relationship of the acoustic wave velocity fitted by the drilling index Dx, which is specifically as follows: taking the well depth at which the logging acoustic wave velocity point begins to appear as the starting point for comparison, converting the acoustic wave velocity fitted by the logging and drilling index Dx into the time per unit depth, calculating the cumulative time required as the depth increases, comparing the travel time of the geological stratification on the seismic profile with the time-depth relationship obtained by the acoustic wave velocity fitted by the logging and drilling index Dx, and checking the difference between the seismic travel time of each layer and the time-depth relationship calculated by drilling and logging.

[0016] Furthermore, the step S1 also includes: if different borehole sections or different types of drill bits cause segmented discontinuity in the drilling index Dx data, it is necessary to pre-process the data by overall translation or increase or decrease, and smooth the points with obvious ambiguity.

[0017] Furthermore, the synthetic seismic record obtained in step S2 is compared with the well logging acoustic wave calibration, and the drilling index Dx is corrected in sections so that the actual drilling index Dx result is close to or consistent with the well logging seismic calibration result.

[0018] The method for establishing a well-seismic relationship for the entire well section based on the drilling index Dx according to claim 1 is characterized in that the calculation formula for the comprehensive parameter of the power exponent of the product of the logging acoustic wave velocity and the drilling index Dx increasing with depth in step S3 is:

[0019] DT_Dx=(Depth) 1 / 6 ×(DT×Dx) 1 / 60 ;

[0020] Where: DT is the acoustic wave velocity, Dx is the drilling index, and Depth is the well depth.

[0021] Further, the formula for the relationship between the drilling index Dx and the comprehensive index constructed by the depth in step S4 is:

[0022]

[0023] In the formula, DT_Dx is regarded as DT_Dx_Trend, DT is the sound wave Dx_Sim to be fitted,

[0024] (Depth) 1 / 6 ×(Dx_Sim×Dx) 1 / 60 =1.0497×(Depth) 0.169972 ,

[0025] The acoustic wave relationship fitted with the Dx index and depth is obtained as follows:

[0026] Dx_Sim=(1.0497) 60 ×(Depth) 0.19833 / Dx;

[0027] Where: Dx_Sim is the acoustic velocity fitted by the drilling index Dx; Depth is the well depth.

[0028] Further, the formula for calculating rock density is:

[0029] Dx_den=0.31×((1 / Dx_Sim)×(1000000 / 3.28)) 0.25 ;

[0030] Where: Dx_Sim is the acoustic velocity (us / ft) fitted by the drilling index Dx.

[0031] Furthermore, the wave impedance Dx_AI is calculated by using the wave impedance calculation formula and the acoustic wave Dx_Sim and density Dx_den fitted by the drilling index Dx:

[0032] Dx_AI=Dx_den×(1 / Dx_Sim)×(1000000 / 3.28);

[0033] Where: Dx_den is the rock density calculated from the acoustic velocity fitted by the drilling index Dx;

[0034] Dx_Sim is the acoustic velocity (us / ft) fitted by the drilling index Dx.

[0035] Another technical solution is: a system for establishing the well-seismic relationship of the entire well section based on the drilling index Dx, characterized by comprising the following modules:

[0036] Drilling index Dx calculation and processing module: obtains the drilling mechanical drilling speed, total drill bit speed, drilling pressure and drill bit size during the drilling process, and calculates the dimensionless parameter drilling index Dx indicating the rock skeleton strength by the formula;

[0037] Well logging data seismic calibration to establish time-depth relationship module: obtain data of well sections with acoustic velocity and density logging projects, make synthetic seismic records based on well logging data, determine the travel time of each formation stratification point on the seismic profile through well logging calibration, and obtain the time-depth relationship curve calculated based on the well logging data through regression;

[0038] Well logging acoustic wave and drilling index Dx trend line fitting module: select well sections with well logging acoustic wave data, construct a comprehensive parameter of the power exponent of the product of acoustic wave velocity and drilling index Dx increasing with depth, perform regression analysis on the comprehensive parameter, and obtain the relationship between the power exponent of the product of acoustic wave velocity and Dx and depth;

[0039] Drilling index Dx fitting acoustic wave velocity and correction module: through the regression formula of the power exponent of the product of acoustic wave velocity and Dx and depth and the constructed comprehensive exponential formula of logging acoustic wave velocity, drilling index Dx and depth, the acoustic wave velocity DT is substituted as the dependent variable to obtain the acoustic wave velocity Dx_Sim fitted with the change of drilling index Dx;

[0040] Drilling index Dx synthetic seismic record module: based on the time-depth relationship determined by the drilling index Dx fitting sound wave, the sound wave velocity Dx_Sim fitted by the drilling index Dx and the Gardner rock density empirical formula are used to calculate Dx_den, and the wave impedance calculation formula is used to calculate the acoustic wave impedance Dx_AI fitted by the drilling index Dx; the reflection coefficient is calculated according to the set sampling interval, and the appropriate sub-wave is selected to perform the deconvolution calculation of the reflection coefficient and the sub-wave product to obtain a synthetic seismic record based on the drilling index Dx;

[0041] Module for making synthetic seismic records for the entire well section based on the drilling index Dx: The fitting acoustic wave velocity Dx_Sim of the entire well section is calculated by the relationship between the drilling index Dx and the acoustic wave velocity Dx_Sim, and then the entire well section Dx_den is calculated by the Gardner rock density empirical formula. The wave impedance calculation formula is used to obtain the wave impedance Dx_AI of the entire well section based on the drilling index Dx, and the production of synthetic seismic records for the entire well section is completed.

[0042] Furthermore, it also includes: a drilling index Dx fitted acoustic wave velocity time-depth relationship comparison module: taking the well depth with logging acoustic wave velocity as the initial point of calculation, converting the acoustic wave velocity fitted by logging and drilling index Dx into time per unit depth, accumulating the time required with depth, comparing the travel time of seismic geological stratification with the time-depth relationship obtained by the acoustic wave velocity fitted by logging and drilling index Dx, and checking the differences between the synthetic seismic records made by drilling and logging.

[0043] The technical effect of the present invention is that: the present invention is a method and system for establishing a well-seismic relationship for the entire well section based on the drilling index Dx. Since the drilling index Dx is a parameter that can be obtained in real time from the start to the completion of the drilling operation, the use of this parameter to fit the acoustic wave velocity and produce synthetic seismic records can make up for the lack of logging acoustic wave velocity data during the drilling process, which makes it impossible to perform timely and accurate well-seismic tracking.

[0044] The synthetic seismic record made by fitting the acoustic wave using the drilling index Dx in the whole well section of the present invention makes up for the defect that the synthetic seismic record cannot be made in the upper formation due to the lack of electrical measurement data, and becomes a full-well section and real-time well seismic calibration that does not rely on logging means. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is the segmented correction diagram of the drilling index Dx of the present invention;

[0046] Figure 2 It is a time-depth relationship diagram of the well logging acoustic wave and density synthesis seismic record calibration of the present invention;

[0047] Figure 3 It is the well logging sonic wave and density synthetic seismic record diagram of the present invention;

[0048] Figure 4 It is a trend fitting diagram of the relationship between the well logging acoustic wave velocity, the drilling index Dx and the depth of the present invention;

[0049] Figure 5 It is a comparison diagram of the well logging acoustic wave velocity and the drilling index Dx fitting acoustic wave velocity of the present invention;

[0050] Figure 6 It is a time-depth relationship diagram of the well logging acoustic wave velocity synthesized seismic record of the present invention;

[0051] Figure 7 It is a time-depth relationship diagram of the synthetic seismic record obtained by fitting the acoustic wave velocity with the drilling index Dx of the present invention;

[0052] Figure 8 It is the drilling index Dx fitting acoustic wave and density synthesis seismic record map of the present invention;

[0053] Fig. 9 It is a comparison chart of the well logging and drilling index Dx fitting acoustic wave and density synthetic seismic records of the present invention;

[0054] Fig.10 It is a time-depth variation diagram of the fitted acoustic wave velocity before and after the full-well drilling index Dx correction of the present invention;

[0055] Fig.11 It is the synthetic seismic record diagram of the drilling index Dx of the whole well section of the present invention;

[0056] Fig.12 It is a flow chart of the method for establishing well-seismic relationship of the entire well section based on the drilling index Dx according to claim 6 of the present invention. DETAILED DESCRIPTION

[0057] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0058] The drilling index Dx is also known as the d-exponent. It is a dimensionless parameter calculated based on the drilling speed (ROP), bit pressure (WOB), bit speed (RPM) and bit size (BitSize) collected during the drilling process through the drilling index Dx empirical formula. This parameter can reflect the drillability of the formation, and its value indicates the strength of the rock skeleton.

[0059] like Figure 1-Figure 12 The method and system for establishing the well and seismic relationship of the entire well section based on the drilling index Dx of the present invention include the following modules and steps.

[0060] 1. Drilling index Dx calculation and processing module

[0061] The dimensionless parameter indicating the strength of the rock skeleton is calculated using the empirical formula reflecting the drillability of the formation. The drilling parameters used are the unit rate of penetration (ROP), the bottom hole drill bit speed (RPM), the bit pressure (WOB) and the drill bit size (BitSize). The formula is as follows:

[0062]

[0063] ROP: drilling rate (m / hr);

[0064] RPM: total drill speed (1 / min);

[0065] WOB: weight on bit (klbm);

[0066] BIT: Drill bit size (In).

[0067] As shown in Table 1, the test data is a list of values ​​for the calculation table of the drilling index Dx of the XX drilling well.

[0068]

[0069] Table 1

[0070] like Figure 1 As shown in the embodiment, due to the discontinuous data segmentation caused by different borehole sections or different types of drill bits, it is necessary to pre-process the data by overall translation or increase or decrease, and smooth the points with obvious ambiguity.

[0071] Since the recorded drilling pressure of the 17.5” wellbore continued to increase during the drilling process, the drilling index Dx was different from that of the subsequent 12.25” wellbore. The data of different wellbore sizes were kept consistent through correction.

[0072] 2. Well logging data seismic calibration to establish time-depth relationship module

[0073] Table 2 shows the calibration results of well logging acoustic wave and density synthetic seismic as shown in the test data. Figure 2 It is a time-depth relationship diagram of the calibration of well logging acoustic wave and density synthetic seismic records of the present invention. The seismic records are synthesized using the well logging acoustic wave velocity and density data. The well and seismic calibration determines the earthquake travel of each stratum point on the seismic profile, and the time-depth relationship curve is obtained by regression. Figure 3 It is a well logging acoustic wave and density synthetic seismic record.

[0074]

[0075] Table 2

[0076] 3. Logging sound wave and drilling index Dx trend line fitting module

[0077] Select the well section with logging acoustic wave data, refer to the Fast formula, and construct a comprehensive parameter of the power exponent of the product of acoustic wave velocity and drilling index Dx increasing with depth. The calculation formula of DT_Dx is:

[0078] DT_Dx=(Depth) 1 / 6 ×(DT×Dx) 1 / 60

[0079] in:

[0080] DT: Speed ​​of sound (us / ft)

[0081] Dx: Drilling index Dx (unitless)

[0082] Depth: Well depth (m)

[0083] As shown in the test data of Table 3, it is a table of calculation results of logging acoustic wave velocity, drilling index Dx and well depth.

[0084] well deep TVDs Speed ​​of sound Dx Index DT_Dx Results 1110 1087 113.05 0.6231 3.4542 1111 1088 107.66 0.5973 3.4495 1112 1089 102.19 0.6551 3.4523 1113 1090 97.77 0.6616 3.4509 1114 1091 107.45 0.6640 3.4570 1115 1092 105.50 0.6904 3.4587 1116 1093 130.45 0.7587 3.4770 1117 1094 114.84 0.8576 3.4772 1118 1095 113.32 0.9067 3.4802 1119 1096 114.78 0.9593 3.4847 1120 1097 108.82 0.8167 3.4728

[0085] Table 3

[0086] The relationship between the parameter and depth obtained by regression is as follows: Figure 4 shown.

[0087] The correlation of the constructed comprehensive parameter with depth regression analysis is 0.9985, indicating that the trend of logging acoustic velocity and drilling index Dx with depth is highly correlated. The expression of the relationship between the two with depth is:

[0088] DT_Dx_Tren=1.05×(Depth) 0.1699

[0089] Due to the limited calculation accuracy in the above formula, the final expression is:

[0090] DT_Dx_Tren=1.0497×(Depth) 0.169972

[0091] Where:

[0092] DT_Dx_Tren: The regression trend line of the comprehensive index of acoustic velocity, Dx and depth (unitless)

[0093] Depth: Well depth (m)

[0094] 4. Drilling index Dx fitting sonic velocity and correction module

[0095] The regression formula of the power exponent of the product of acoustic velocity and Dx and depth is linked with the constructed comprehensive exponential formula of logging acoustic velocity, drilling index Dx and depth. The acoustic velocity DT in the formula is used as the dependent variable to obtain the fitted acoustic velocity Dx_Sim relationship with the change of drilling index Dx and depth:

[0096]

[0097] In the formula, DT_Dx is regarded as DT_Dx_Tren, DT is regarded as the acoustic wave Dx_Sim to be fitted,

[0098] (Depth) 1 / 6 ×(Dx_Sim×Dx) 1 / 60 =1.0497×(Depth) 0.169972

[0099] Get the acoustic wave velocity Dx_Sim fitted by the drilling index Dx changing with depth:

[0100] Dx_Sim=(1.0497) 60 ×(Depth) 0.19833 / Dx

[0101] Where:

[0102] Dx_Sim: Fitting acoustic velocity with drilling index Dx and well depth changes (us / ft)

[0103] Depth: Well depth (m)

[0104] The calculation results of the drilling index Dx fitting sonic velocity are shown in Table 4:

[0105] well deep TVDs DT sound wave speed Dx Index Dx_Sim Results 1110 1087 113.05 0.6231 118.3869 1111 1088 107.66 0.5973 123.5346 1112 1089 102.19 0.6551 112.6512 1113 1090 97.77 0.6616 111.5715 1114 1091 107.45 0.6640 111.1811 1115 1092 105.50 0.6904 106.9414 1116 1093 130.45 0.7587 97.3357 1117 1094 114.84 0.8576 86.1273 1118 1095 113.32 0.9067 81.4812 1119 1096 114.78 0.9593 77.0222 1120 1097 108.82 0.8167 90.4901

[0106] Table 4 The statistical results of the well logging and Dx fitting acoustic wave velocity are as follows: Table 5:

[0107]

[0108] Table 5

[0109] The statistical results show that the maximum and minimum variation ranges of the acoustic velocity fitted by the drilling index Dx are larger than those of the logging results, but the difference in the average values ​​is relatively small.

[0110] like Figure 5As shown in the figure, the comparison chart of well logging acoustic velocity and drilling index Dx fitting acoustic velocity. The superposition chart of the two data sources shows that the acoustic velocity of Dx fitting and the well logging acoustic velocity are highly similar. In order to maintain the authenticity of the drilling index Dx fitting acoustic wave data as much as possible, no smoothing or filtering was performed on the Dx data in this calculation.

[0111] 5. Drilling index Dx fitting acoustic wave velocity time-depth relationship comparison module

[0112] The well depth with logging acoustic velocity is used as the initial point of calculation, and the acoustic velocity fitted by logging and drilling index Dx is converted into the time per unit depth (in this case, the time required for every 1 meter), and the time required with depth is accumulated; considering that the well depth measurement systems used in logging and drilling are different, there is a problem of well depth unification between the two. In this example, the EP210 main target layer is selected as the reference surface of the accumulated time, and the travel time of seismic geological stratification is compared with the time-depth relationship obtained by the acoustic velocity fitted by logging and drilling index Dx, and the difference between the synthetic seismic records made by drilling and logging is checked. Table 6 is a comparison table of the accumulated time of logging, Dx fitting acoustic velocity and seismic travel time.

[0113]

[0114] Table 6

[0115] in, Figure 6 The time-depth relationship diagram of the synthetic seismic record of the well logging acoustic wave velocity is shown in Figure 1. Figure 7 Fit the acoustic velocity time-depth relationship of synthetic seismic records for the drilling index Dx. Fit the acoustic velocity time-depth relationship regression curve and correlation coefficient. There are only slight differences between the two formulas.

[0116] Depend on Figure 6 Well logging and Figure 7 The comparison results of the time-depth relationship diagram of the drilling index Dx fitting the sound wave velocity show that the time-depth relationship of the sound wave fitted by the drilling index Dx can also well reflect the propagation law of longitudinal waves in rocks with different wave impedances. At the same time, the statistical results show that the time-depth relationship of the sound wave fitted by the drilling index Dx is closer to the travel time of seismic geological stratification.

[0117] 6. Drilling Index Dx Synthetic Seismic Recording Module

[0118] Based on the time-depth relationship determined by fitting the acoustic wave with the drilling index Dx, the acoustic wave velocity fitted by the drilling index Dx and the rock density calculated by the Gardner formula are used to calculate the wave impedance; the reflection coefficient is calculated at a certain sampling interval (usually 2ms), and a suitable sub-wave (usually 30Hz Ricker wavelet, length 128ms and zero phase) is selected to perform deconvolution calculation of the reflection coefficient and the product of the sub-wavelet, and the following is obtained: Figure 8As shown, the fitted acoustic wave and density synthetic seismic records based on the drilling index Dx.

[0119] Gardner formula to calculate rock density:

[0120] Dx_den=0.31×((1 / Dx_Sim)×(1000000 / 3.28)) 0.25

[0121] Where:

[0122] Dx_Sim: Fit the acoustic wave velocity (us / ft) by the drilling index Dx.

[0123] The calculation formula of drilling index Dx fitting acoustic wave impedance is:

[0124] Dx_AI=Dx_den×(1 / Dx_Sim)×(1000000 / 3.28)

[0125] Where:

[0126] Dx_Sim: Fit the acoustic wave velocity (us / ft) from the drilling index Dx.

[0127] The calculation formula of drilling index Dx fitting acoustic wave reflection coefficient is as follows:

[0128] Dx_Re (i+1) =(Dx_AI (i+1) -Dx_AI (i) ) / (Dx_AI (i+1) +Dx_AI (i) )i=1,2,…n

[0129] Where:

[0130] Dx_Re (i+1) : Reflection coefficient when the well depth is i+1.

[0131] The calculation formula for synthetic seismic records is:

[0132] S(t)=R(t)×W(t)

[0133] Where:

[0134] S(t): synthetic seismic record;

[0135] R(t): reflection coefficient sequence (Dx_Re in this case):

[0136] W(t): seismic wavelet (30Hz Ricker wavelet is selected in this example).

[0137] Fig. 9To compare the synthetic seismic records produced by using the acoustic wave, density and time-depth relationship of the logging data with the drilling index Dx fitting of the acoustic wave, density and time-depth relationship.

[0138] By comparing and analyzing the synthetic seismic records produced by the two data sources, it is found that the two have a high degree of similarity. The results show that the drilling index Dx can also be used for synthetic seismic records, which has the real-time performance that well logging does not have, and can realize well and seismic comparison and tracking of the entire well section.

[0139] 7. Synthetic seismic record module for the whole well section drilling index Dx

[0140] The drilling index Dx is the data that can be obtained from the start of drilling to the completion of drilling. As mentioned above, the drilling index Dx may need to be corrected due to different wellbore sizes or the use of different types of drill bits. Fig.10 The figure shows the relationship between the change of the drilling index Dx before and after correction of the entire well section and the fitting acoustic wave time-depth of the drilling index Dx.

[0141] In this embodiment, after the drilling index Dx is corrected for the 17.5” borehole size, the time-depth relationship is shifted overall. Table 7 shows the statistical results of the time-depth relationship changes before and after the drilling index Dx correction.

[0142]

[0143] Table 7

[0144] The density is calculated using Gardner's empirical formula, and combined with the full-well acoustic wave fitted with the drilling index Dx, the wave impedance based on the drilling index Dx is finally calculated, and the production of synthetic seismic records of the entire well section is completed.

[0145] Fig.11 The synthetic seismic records made for the entire well section using the drilling index Dx to fit the acoustic waves make up for the defect that synthetic seismic records cannot be made for the upper formation due to the lack of electrical logging data, and realize the full-well section and real-time well seismic calibration independent of logging.

[0146] Figure 1-Figure 10 The relationship diagram is as follows. According to the actual seismic layer, lithology, well depth, vertical depth and drilling index Dx data, the specific values ​​in the figure also change accordingly. This data is within the protection scope of this application, and the curve in the figure only expresses the trend of change.

[0147] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0148] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process and related instructions of the storage device and processing device described above can refer to the corresponding process in the aforementioned method embodiment and will not be repeated here.

[0149] Those skilled in the art should be able to appreciate that the modules and method steps of each example described in conjunction with the embodiments disclosed herein can be implemented with electronic hardware, computer software or a combination of the two, and the programs corresponding to the software modules and method steps can be placed in random access memory (RAM), memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs or any other form of storage medium known in the technical field. In order to clearly illustrate the interchangeability of electronic hardware and software, the composition and steps of each example have been generally described in the above description according to the function. Whether these functions are performed in electronic hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0150] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "top / bottom" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0151] The above-described embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or changes made by those skilled in the art based on the present invention are within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A method for establishing a well-seismic relationship for the entire well section based on a drilling index Dx, characterized in that: The following steps are involved: Step S1: obtaining the drilling speed, total drill bit speed, drilling pressure and drill bit size of the drilling machine using the drilling parameters as the data source during the drilling process, and calculating the dimensionless parameter drilling index Dx indicating the rock skeleton strength; Step S2: Acquire the data of the well section with acoustic velocity and density logging items, make synthetic seismic records based on the logging data, determine the travel time of each formation stratification point on the seismic profile by well seismic calibration, and obtain the time-depth relationship curve calculated based on the logging data by regression; Step S3: selecting a well section with logging acoustic wave data, constructing a comprehensive parameter whose power exponent of the product of logging acoustic wave velocity and drilling index Dx increases with depth, and obtaining a relationship between the burial depth of the formation and the drilling index Dx and logging acoustic wave velocity through regression analysis; Step S4: The relationship between the burial depth of the formation, the drilling index Dx and the acoustic wave velocity obtained by regression analysis is linked to the comprehensive index relationship constructed by the logging acoustic wave velocity, the drilling index Dx and the depth, and the acoustic wave velocity DT in the relationship is regarded as an unknown quantity, so as to obtain a relationship for calculating the acoustic wave velocity Dx_Sim from the drilling index Dx; Step S5: Calculate the time-depth relationship based on the acoustic wave velocity Dx_Sim calculated based on the drilling index Dx, substitute the acoustic wave velocity Dx_Sim fitted by the drilling index Dx into the Gardner empirical formula to calculate the rock density Dx_den, substitute the acoustic wave velocity Dx_Sim and rock density Dx_den fitted by Dx into the wave impedance calculation formula to obtain the wave impedance value Dx_AI, calculate the reflection coefficient according to the set sampling interval, select a suitable sub-wave, perform deconvolution calculation of the reflection coefficient and the wavelet product, and obtain a synthetic seismic record based on the drilling index Dx; Step S6: Calculate the fitted acoustic wave velocity Dx_Sim from the drilling index Dx of the entire well section, and calculate the rock density using the Gardner empirical formula, and finally obtain the wave impedance Dx_AI of the entire well section based on the drilling index Dx, completing the production of synthetic seismic records of the entire well section.

2. The method for establishing the well-seismic relationship of the entire well section based on the drilling index Dx according to claim 1, characterized in that: The step S3 also includes a step of comparing the time-depth relationship of the acoustic wave velocity fitted by the drilling index Dx, which is specifically as follows: taking the well depth where the logging acoustic wave velocity point starts as the starting point for comparison, converting the acoustic wave velocity fitted by the logging and drilling index Dx into the time per unit depth, calculating the cumulative time required as the depth increases, comparing the travel time of the geological stratification on the seismic profile with the time-depth relationship obtained by the acoustic wave velocity fitted by the logging and drilling index Dx, and checking the difference between the seismic travel time of each layer and the time-depth relationship calculated by drilling and logging.

3. The method for establishing the well-seismic relationship of the entire well section based on the drilling index Dx according to claim 1, characterized in that: The step S1 also includes: if different borehole sections or different types of drill bits cause segmented discontinuity in the drilling index Dx data, it is necessary to pre-process the data by overall translation or increase or decrease, and smooth the points with obvious ambiguity.

4. The method for establishing the well-seismic relationship of the entire well section based on the drilling index Dx according to claim 1, characterized in that: The synthetic seismic record obtained in step S2 is compared with the well logging acoustic wave calibration result, and the drilling index Dx is corrected in sections so that the actual drilling index Dx result is close to or consistent with the well logging seismic calibration result.

5. The method for establishing the well-seismic relationship of the entire well section based on the drilling index Dx according to claim 1, characterized in that: The calculation formula of the comprehensive parameter of the power exponent of the product of the logging acoustic velocity and the drilling index Dx in step S3 increases with depth is: DT_Dx=(Depth) 1 / 6 ×(DT×Dx) 1 / 60 ; Where: DT is the acoustic wave velocity, Dx is the drilling index, and Depth is the well depth.

6. The method for establishing the well-seismic relationship of the entire well section based on the drilling index Dx according to claim 1, characterized in that: The formula for the relationship between the drilling index Dx and the comprehensive index constructed by the depth in step S4 is: In the formula, DT_Dx is regarded as DT_Dx_Trend, DT is the sound wave Dx_Sim to be fitted, (Depth) 1 / 6 ×(Dx_Sim×Dx) 1 / 60 =1.0497×(Depth) 0.169972 , the acoustic wave relationship fitted with the Dx index and depth is obtained as follows: Dx_Sim=(1.0497) 60 ×(Depth) 0.19833 / Dx; Where: Dx_Sim is the acoustic velocity fitted by the drilling index Dx, and Depth is the well depth.

7. The method for establishing the well-seismic relationship of the entire well section based on the drilling index Dx according to claim 6, characterized in that: The formula for calculating rock density is: Dx_den=0.31×((1 / Dx_Sim)×(1000000 / 3.28)) 0.25 ; Where: Dx_Sim is the acoustic velocity (us / ft) fitted by the drilling index Dx.

8. The method for establishing the well-seismic relationship of the entire well section based on the drilling index Dx according to claim 6, characterized in that: Using the wave impedance calculation formula, the wave impedance Dx_AI is calculated through the acoustic wave Dx_Sim and density Dx_den fitted by the drilling index Dx: Dx_AI=Dx_den×(1 / Dx_Sim)×(1000000 / 3.28); Where: Dx_den is the rock density calculated by the acoustic wave velocity fitted by the drilling index Dx; Dx_Sim is the acoustic wave velocity fitted by the drilling index Dx.

9. A system for establishing well-seismic relationship of the entire well section based on drilling index Dx, characterized in that: Includes the following modules: Drilling index Dx calculation and processing module: obtains the drilling mechanical drilling speed, total drill bit speed, drilling pressure and drill bit size during the drilling process, and calculates the dimensionless parameter drilling index Dx indicating the rock skeleton strength by the formula; Well logging data seismic calibration to establish time-depth relationship module: obtain data of well sections with acoustic velocity and density logging projects, make synthetic seismic records based on well logging data, determine the travel time of each formation stratification point on the seismic profile through well logging calibration, and obtain the time-depth relationship curve calculated based on the well logging data through regression; Well logging acoustic wave and drilling index Dx trend line fitting module: select well sections with well logging acoustic wave data, construct a comprehensive parameter of the power exponent of the product of acoustic wave velocity and drilling index Dx increasing with depth, perform regression analysis on the comprehensive parameter, and obtain the relationship between the power exponent of the product of acoustic wave velocity and Dx and depth; Drilling index Dx fitting acoustic wave velocity and correction module: through the regression formula of the power exponent of the product of acoustic wave velocity and Dx and depth and the constructed comprehensive exponential formula of logging acoustic wave velocity, drilling index Dx and depth, the acoustic wave velocity DT is substituted as the dependent variable to obtain the acoustic wave velocity Dx_Sim fitted with the change of drilling index Dx; Drilling index Dx synthetic seismic record module: based on the time-depth relationship determined by the drilling index Dx fitting sound wave, the sound wave velocity Dx_Sim fitted by the drilling index Dx and the Gardner rock density empirical formula are used to calculate Dx_den, and the wave impedance calculation formula is used to calculate the acoustic wave impedance Dx_AI fitted by the drilling index Dx; the reflection coefficient is calculated according to the set sampling interval, and the appropriate sub-wave is selected to perform the deconvolution calculation of the reflection coefficient and the sub-wave product to obtain a synthetic seismic record based on the drilling index Dx; Module for making synthetic seismic records for the entire well section based on the drilling index Dx: The fitting acoustic wave velocity Dx_Sim of the entire well section is calculated by the relationship between the drilling index Dx and the acoustic wave velocity Dx_Sim, and then the entire well section Dx_den is calculated by the Gardner rock density empirical formula. The wave impedance calculation formula is used to obtain the wave impedance Dx_AI of the entire well section based on the drilling index Dx, and the production of synthetic seismic records for the entire well section is completed.

10. A system for establishing a well-seismic relationship for the entire well section based on the drilling index Dx as claimed in claim 9, characterized in that: It also includes: Drilling index Dx fitting acoustic wave velocity time-depth relationship comparison module: Take the well depth with logging acoustic wave velocity as the initial point of calculation, convert the acoustic wave velocity fitted by logging and drilling index Dx into time per unit depth, accumulate the time required with depth, compare the travel time of seismic geological stratification with the time-depth relationship obtained by the acoustic wave velocity fitted by logging and drilling index Dx, and check the differences between the synthetic seismic records made by drilling and logging.

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