Real-time quantitative recognition method and system for deep stratum interface while drilling

Abstract

The invention relates to a real-time quantitative identification method and system for a deep stratum interface while drilling, and belongs to the field of oil-gas exploration drilling geology. The method comprises the following steps: establishing lithology parameter distribution characteristics of an overlying stratum of a stratum while drilling; estimating lithology parameter distribution characteristics of the formation while drilling in real time; and identifying whether the formation while drilling is a new formation based on the lithologic parameter distribution characteristics of the formation while drilling and the lithologic parameter distribution characteristics of the overlying formation. Quantitative identification of the stratum interface is achieved by comparing the lithology parameter data of the overlying stratum and the stratum while drilling, the method is not affected by the well depth, real-time identification can be achieved, the identification process is greatly simplified, calculation is easy, the stratum interface can be directly determined through quantitative data, and the method has the advantages of being high in accuracy and high in reliability. A reliable foundation is provided for guaranteeing drilling safety and achieving oil and gas discovery, the effect in practical application is good, and the problem puzzling related personnel for a long time in deep well and ultra-deep well strata clamping layers is solved.

Description

Technical Field

[0001] The invention belongs to the field of oil and gas exploration drilling geology, and particularly relates to a real-time quantitative identification method and system for deep-layer formation interface while drilling. Background Art

[0002] Conventional drilling geological lithology identification is preliminarily determined based on changes in drilling time. The target layer section is identified by circulating drilling fluid to identify the lithology of the returned cuttings; or by coring the well to identify the lithology of the core. The conventional method of identifying the formation interface is to determine whether the lithology has changed significantly. The above method of identifying the formation interface based on changes in drilling time has problems such as difficulty in identification, large errors, long time consumption, high requirements on personnel ability, large subjective influence, and poor efficiency in deep and ultra-deep well drilling. Summary of the invention

[0003] In view of the above problems, the present invention proposes a real-time quantitative identification method and system for deep formation interfaces while drilling, which is a mathematical and statistical method while drilling. Through sampling, parameter estimation, hypothesis testing, in the form of data and quantitativeness, it eliminates the influence of accidental factors in the drilling process to the greatest extent and identifies whether the formation while drilling is a new formation.

[0004] The first object of the present invention is to provide a real-time quantitative identification method of deep formation interface while drilling, the method comprising:

[0005] Establish the distribution characteristics of lithological parameters of overlying strata while drilling the strata;

[0006] Real-time estimation of the distribution characteristics of lithology parameters of the formation while drilling;

[0007] Based on the distribution characteristics of lithological parameters of the formation being drilled and the distribution characteristics of lithological parameters of the overlying formation, it is identified whether the formation being drilled is a new formation.

[0008] In the embodiment of the present invention, the lithology parameters include cuttings characteristics, drilling time and rock strength.

[0009] In an embodiment of the present invention, the establishment of the lithology parameter distribution characteristics of the overlying strata of the formation while drilling includes:

[0010] sampling of overlying strata while drilling;

[0011] Estimate lithological parameter values ​​within determined confidence intervals;

[0012] Based on the lithology parameter values ​​in the confidence interval, the distribution characteristics of the lithology parameters of the overlying strata of the formation being drilled are obtained.

[0013] In the embodiment of the present invention, the estimation method in estimating the lithology parameter value within the determined confidence interval is the same as the estimation method in estimating the lithology parameter distribution characteristics of the formation while drilling in real time.

[0014] In an embodiment of the present invention, the real-time estimation of the distribution characteristics of lithological parameters of the formation while drilling includes:

[0015] Real-time formation sampling while drilling;

[0016] Estimate the lithology parameter values ​​and lithology parameter ranges of the formation while drilling;

[0017] Based on the lithology parameter values ​​and lithology parameter intervals, the distribution characteristics of the lithology parameters of the formation while drilling are obtained.

[0018] In the embodiment of the present invention, the formation being drilled is a formation that is expected to be drilled above and below the formation interface and is being drilled, wherein the basis for the prediction is reference to the drilling geological design or surrounding well data.

[0019] In an embodiment of the present invention, the step of identifying whether the formation being drilled is a new formation based on the distribution characteristics of lithology parameters of the formation being drilled and the distribution characteristics of lithology parameters of the overlying formation includes:

[0020] Compare the distribution characteristics of lithological parameters of the formation being drilled with those of the overlying formation;

[0021] Based on the comparison result, it is identified whether the formation being drilled is a new formation.

[0022] The second object of the present invention is to provide a real-time quantitative identification system for deep formation interface while drilling, the system comprising:

[0023] The establishment module is used to establish the lithology parameter distribution characteristics of the overlying strata of the formation while drilling;

[0024] The real-time estimation module is used to estimate the distribution characteristics of lithology parameters of the formation while drilling in real time;

[0025] The identification module is used to identify whether the formation being drilled is a new formation based on the distribution characteristics of the lithology parameters of the formation being drilled and the distribution characteristics of the lithology parameters of the overlying formation.

[0026] In the embodiment of the present invention, the real-time estimation module includes an overlying stratum sampling submodule, an overlying stratum estimation submodule and an acquisition submodule;

[0027] The overburden stratum sampling submodule is used to sample the overburden stratum of the formation while drilling;

[0028] The overlying stratum estimation submodule is used to estimate the lithology parameter value within a determined confidence interval;

[0029] The obtaining submodule obtains the lithology parameter distribution characteristics of the overlying strata of the formation being drilled based on the lithology parameter values ​​in the confidence interval.

[0030] In the embodiment of the present invention, the real-time estimation module includes a formation sampling while drilling submodule, a formation estimation while drilling submodule and a determination submodule;

[0031] The formation sampling while drilling submodule is used to sample the formation while drilling in real time;

[0032] The formation estimation while drilling submodule is used to estimate the lithology parameter value and lithology parameter interval of the formation while drilling;

[0033] The determination submodule is used to obtain the distribution characteristics of the lithology parameters of the formation while drilling based on the lithology parameter values ​​and lithology parameter intervals.

[0034] A third object of the present invention is to provide an electronic device, the electronic device comprising: a processor, the processor being coupled to a memory;

[0035] The memory is used to store computer programs;

[0036] The processor is used to execute the computer program stored in the memory so that the electronic device executes the method as described above.

[0037] A fourth object of the present invention is to provide a computer-readable storage medium, wherein the computer-readable storage medium stores a program or instruction, and when the program or instruction is executed on a computer, the computer executes the method as described above.

[0038] Beneficial effects of the present invention:

[0039] The present invention provides a real-time quantitative identification method and system for deep formation interface while drilling. By comparing the lithological parameter data between the overlying stratum and the formation while drilling, the formation interface (whether the formation while drilling is a new stratum) is identified. The method is not affected by the well depth and can be identified in real time. The method is the first to use mathematical methods to realize the quantitative identification of formation interface while drilling. The identification process is greatly simplified and easy to calculate. The formation interface can be directly determined using quantitative data, which provides a reliable basis for ensuring drilling safety and realizing oil and gas discovery. The method has good effects in practical applications and solves the problem of formation stuckness that has long troubled relevant personnel in deep wells and ultra-deep wells.

[0040] And by increasing the sampling density, accurate identification of the stratigraphic interface can be achieved.

[0041] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 A flow chart of a method for real-time quantitative identification of deep formation interface while drilling according to an embodiment of the present invention is shown;

[0044] Figure 2 A comparison diagram of the recognition results of the real-time quantitative recognition method according to an embodiment of the present invention and the conventional method is shown;

[0045] Figure 3 A framework diagram of a real-time quantitative identification system for deep formation interface while drilling according to an embodiment of the present invention is shown;

[0046] Figure 4 A framework diagram of an electronic device according to an embodiment of the present invention is shown;

[0047] In the figure:

[0048] Establishing module 1; real-time estimating module 2; identifying module 3; electronic device 300; processor 301; memory 302. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0050] like Figure 1 As shown, a real-time quantitative identification method of deep formation interface while drilling according to the present invention comprises:

[0051] Step S1, establishing the lithology parameter distribution characteristics of the overlying strata of the drilling stratum;

[0052] Step S2, estimating the distribution characteristics of lithology parameters of the formation while drilling in real time;

[0053] Step S3: based on the lithology parameter distribution characteristics of the formation being drilled and the lithology parameter distribution characteristics of the overlying formation, identifying whether the formation being drilled is a new formation.

[0054] In step S1, the lithology parameters include cuttings characteristics, drilling time and rock strength (obtained based on engineering parameters recorded in real time);

[0055] In step S1, the establishment of the lithology parameter distribution characteristics of the overlying strata of the formation while drilling includes:

[0056] Step A1, sampling the overlying strata of the drilling strata, wherein the sampling method is determined according to the specific lithology combination. If the lithology is mainly thick layers and the lithology difference of the single layer is small, the systematic sampling method is adopted for sampling; if the lithology is mainly interlayered and the thickness varies greatly, the stratified sampling method is adopted for sampling;

[0057] Step A2, estimating the lithology parameter value within the determined confidence interval. Specifically, the confidence interval is determined based on the sample data obtained by sampling the overlying strata, and then the lithology parameter value is estimated within the determined confidence interval. The method for determining the confidence interval is determined according to the accuracy required by the geological design. The general principle is that the interval range of non-target layers (overburden layers) can be relaxed, and the interval range of target layers and new strata (drilling layers) is small.

[0058] Step A3: Based on the lithology parameter values ​​in the confidence interval, obtain the lithology parameter distribution characteristics of the overlying strata of the drilling formation. Specifically, the lithology parameter distribution characteristics of the overlying strata of the drilling formation are formed by combining the confidence interval in step A2 and the corresponding lithology parameter values ​​under the confidence interval;

[0059] The estimation method in step A3 is the same as that in step S2, that is, the estimation method in estimating the lithology parameter value within the determined confidence interval is the same as the estimation method in real-time estimating the distribution characteristics of the lithology parameter of the formation while drilling;

[0060] Specifically, the estimation method is as follows:

[0061] The expressions of mean and variance are shown in equations (1)-(2).

[0062]

[0063]

[0064] In formula (1)-(2), is the mean, is the average of the parent sample, is the variance, s is the mean square error;

[0065] The expression of the confidence interval is shown in formula (3).

[0066]

[0067] In formula (3), the confidence probability is 1-α, X is the average number of samples, S *is the sub-sample standard deviation, and n is the sub-sample size.

[0068] In step S2, the real-time estimation of the distribution characteristics of the lithology parameters of the formation while drilling includes:

[0069] Step B1, sampling the formation while drilling in real time, wherein the sampling method is the same as the sampling method in step A1;

[0070] Step B2, estimating the lithology parameter value and lithology parameter interval of the formation while drilling, the estimation method is as follows: formula (1)-(3), wherein the confidence interval of the parent data of the formation while drilling is determined according to formula (3), and then the lithology parameter interval is determined (that is, the lithology parameter interval is the confidence interval corresponding to the lithology parameter);

[0071] Step B3: Based on the lithology parameter values ​​and lithology parameter intervals, obtain the lithology parameter distribution characteristics of the formation while drilling. Specifically, based on the lithology parameter values ​​determined in step B2 and the corresponding core parameter intervals, obtain the lithology parameter distribution characteristics of the formation while drilling.

[0072] In step S2, the drilling-while-drilling formation is the formation that is expected to be drilled above and below the formation interface and is being drilled, wherein the estimation is based on reference drilling geological design or surrounding well data. By way of example, in an embodiment of the present invention, based on the design logging accuracy requirements (drilling geological design data), it is determined as the drilling-while-drilling formation 50 to 100 meters (i.e., a predetermined distance) in advance.

[0073] In step S3, the step of identifying whether the formation being drilled is a new formation based on the distribution characteristics of the lithology parameters of the formation being drilled and the distribution characteristics of the lithology parameters of the overlying formation comprises:

[0074] Step C1, comparing the distribution characteristics of the lithology parameters of the formation being drilled with the distribution characteristics of the lithology parameters of the overlying formation;

[0075] Step C2: Based on the comparison result, identify whether the formation being drilled is a new formation.

[0076] In step C1, the lithology parameter distribution characteristics of the drilling formation are compared with the lithology parameter distribution characteristics of the overlying formation. Once a deviation occurs, the drilling formation is identified as a new formation. This conclusion is the identification result (the identification process is to identify whether the drilling formation is a new formation based on the comparison result in step C2);

[0077] In the embodiment of the present invention, the drilling in a certain area is exemplarily taken as the identification object, and the identification results of Table 1 (parameter value comparison) and Table 2 (interval comparison) are obtained. In Table 1, 2σ is twice the mean square error, and μ is the mathematical expectation value.

[0078] Table 1

[0079]

[0080] Table 2

[0081]

[0082] Confidence probability: 99%

[0083] Step C2 may also be to identify whether the formation being drilled is a new formation based on a verification rule, wherein the verification rule is:

[0084] Determine the assumed stratum lithology. If the new stratum is not drilled, the overlying stratum is taken as the parent body, and μ0 is known at this time. Make assumptions within the stratum while drilling, and assume that the expression is shown in formula (4);

[0085] H0:μ=μ0 (4)

[0086] use (formation samples while drilling) for inspection, μ is the formation data while drilling;

[0087] Formula (5) is expressed as a t distribution with n-1 degrees of freedom:

[0088]

[0089] In formula (5), is the sample mean, μ0 is the mathematical expectation of the population, S * is the sample mean square error, n is the number of samples;

[0090] Given α = 0.01, determine The value of

[0091]

[0092] like

[0093] If the hypothesis H0 is rejected, it is considered that a new stratum has been drilled. Otherwise, the hypothesis is accepted, and it is considered that a new stratum has not been drilled.

[0094] Variance test

[0095] Assume that the overlying strata and lithology while drilling are the parent body Draw subsamples respectively, with capacity and variance of n1, and n2, but It follows an F distribution with degrees of freedom (n1-1, n2-1). Given a confidence level α, if

[0096] or Then H0 is rejected and the formation while drilling is considered to be a new formation.

[0097] if

[0098]

[0099] Then we accept H0 and believe that no new stratum has been drilled.

[0100] Based on the test rules in step C2, the recognition result table 3 (results of hypothesis test recognition) in the embodiment of the present invention is obtained.

[0101] Table 3

[0102]

[0103] The comparison of the effect of the formation map while drilling identified by the above embodiment and the formation map while drilling identified by the conventional method (drilling) is shown in the figure below. Figure 2 As shown, Figure 2 In the figure, the first column is the formation name, the second column is the drilling characteristics, the fourth column (logging while drilling parameters) is the result of the identification method provided by the embodiment of the present invention, the fifth column is the drilling depth, the sixth column is the formation lithology map, and the third, seventh and eighth columns are later parameter verification maps;

[0104] from Figure 2 It can be seen from the figure that the recognition method in the above embodiment is accurate in recognition.

[0105] like Figure 3 As shown, a real-time quantitative identification system of deep formation interface while drilling according to the present invention comprises:

[0106] Establishing module 1 is used to establish the lithology parameter distribution characteristics of the overlying strata of the formation while drilling;

[0107] Real-time estimation module 2 is used to estimate the distribution characteristics of lithology parameters of formations while drilling in real time;

[0108] The identification module 3 is used to identify whether the formation being drilled is a new formation based on the distribution characteristics of the lithology parameters of the formation being drilled and the distribution characteristics of the lithology parameters of the overlying formation.

[0109] In the embodiment of the present invention, the real-time estimation module 1 includes an overlying stratum sampling submodule, an overlying stratum estimation submodule and an acquisition submodule;

[0110] The overburden stratum sampling submodule is used to sample the overburden stratum of the formation while drilling;

[0111] The overlying stratum estimation submodule is used to estimate the lithology parameter value within a determined confidence interval;

[0112] The obtaining submodule obtains the lithology parameter distribution characteristics of the overlying strata of the formation being drilled based on the lithology parameter values ​​in the confidence interval.

[0113] In the embodiment of the present invention, the real-time estimation module 2 includes a formation sampling while drilling submodule, a formation estimation while drilling submodule and a determination submodule;

[0114] The formation sampling while drilling submodule is used to sample the formation while drilling in real time;

[0115] The formation estimation while drilling submodule is used to estimate the lithology parameter value and lithology parameter interval of the formation while drilling;

[0116] The determination submodule is used to obtain the distribution characteristics of the lithology parameters of the formation while drilling based on the lithology parameter values ​​and lithology parameter intervals.

[0117] like Figure 4 As shown, some embodiments of the present invention provide an electronic device, the electronic device 300, comprising: a processor 301, the processor 301 is coupled to a memory 302;

[0118] The memory 302 is used to store computer programs;

[0119] The processor 301 is configured to execute the computer program stored in the memory 302 so that the electronic device executes the method described in the above embodiment.

[0120] In certain embodiments of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a program or instruction. When the program or instruction is executed on a computer, the computer executes the method described in the above embodiments.

[0121] According to an embodiment of the present invention, the computer-readable storage medium may be a non-volatile computer-readable storage medium, for example, may include but is not limited to: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present invention, a computer-readable storage medium may be any tangible medium containing or storing a program, which may be used by or in combination with an instruction execution system, an electronic device or a device.

[0122] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A real-time quantitative identification method for deep formation interface while drilling, characterized in that: include: Establish the distribution characteristics of lithological parameters of overlying strata while drilling the strata; Real-time estimation of the distribution characteristics of lithology parameters of the formation while drilling; Based on the distribution characteristics of lithological parameters of the formation being drilled and the distribution characteristics of lithological parameters of the overlying formation, it is identified whether the formation being drilled is a new formation.

2. The real-time quantitative identification method of deep formation interface while drilling according to claim 1, characterized in that: The lithology parameters include cuttings characteristics, drilling time and rock strength.

3. The real-time quantitative identification method of deep formation interface while drilling according to claim 1, characterized in that: The establishment of the lithology parameter distribution characteristics of the overlying strata of the formation while drilling comprises: sampling of overlying strata while drilling; Estimate lithological parameter values ​​within determined confidence intervals; Based on the lithology parameter values ​​in the confidence interval, the distribution characteristics of the lithology parameters of the overlying strata of the formation being drilled are obtained.

4. The real-time quantitative identification method of deep formation interface while drilling according to claim 3 is characterized in that: The estimation method in estimating the lithology parameter value within the determined confidence interval is the same as the estimation method in real-time estimating the distribution characteristics of the lithology parameter of the formation while drilling.

5. The real-time quantitative identification method of deep formation interface while drilling according to claim 1, characterized in that: The real-time estimation of the distribution characteristics of lithology parameters of the formation while drilling includes: Real-time formation sampling while drilling; Estimate the lithology parameter values ​​and lithology parameter ranges of the formation while drilling; Based on the lithology parameter values ​​and lithology parameter intervals, the distribution characteristics of the lithology parameters of the formation while drilling are obtained.

6. The real-time quantitative identification method of deep formation interface while drilling according to claim 1, characterized in that: The formation being drilled refers to the formation being drilled above and below the formation interface that is expected to be drilled, wherein the basis for the prediction is reference to the drilling geological design or surrounding well data.

7. The real-time quantitative identification method of deep formation interface while drilling according to any one of claims 1 to 6, characterized in that: The identifying whether the formation being drilled is a new formation based on the distribution characteristics of the lithology parameters of the formation being drilled and the distribution characteristics of the lithology parameters of the overlying formation comprises: Compare the distribution characteristics of lithological parameters of the formation being drilled with those of the overlying formation; Based on the comparison result, it is identified whether the formation being drilled is a new formation.

8. A real-time quantitative identification system for deep formation interface while drilling, characterized in that: include: The establishment module is used to establish the lithology parameter distribution characteristics of the overlying strata of the formation while drilling; The real-time estimation module is used to estimate the distribution characteristics of lithology parameters of the formation while drilling in real time; The identification module is used to identify whether the formation being drilled is a new formation based on the distribution characteristics of the lithology parameters of the formation being drilled and the distribution characteristics of the lithology parameters of the overlying formation.

9. The real-time quantitative identification system of deep formation interface while drilling according to claim 8, characterized in that: The real-time estimation module includes an overlying stratum sampling submodule, an overlying stratum estimation submodule and an acquisition submodule; The overburden stratum sampling submodule is used to sample the overburden stratum of the formation while drilling; The overlying stratum estimation submodule is used to estimate the lithology parameter value within a determined confidence interval; The obtaining submodule obtains the lithology parameter distribution characteristics of the overlying strata of the formation being drilled based on the lithology parameter values ​​in the confidence interval.

10. The real-time quantitative identification system of deep formation interface while drilling according to claim 8, characterized in that: The real-time estimation module includes a formation sampling while drilling submodule, a formation estimation while drilling submodule and a determination submodule; The formation sampling while drilling submodule is used to sample the formation while drilling in real time; The formation estimation while drilling submodule is used to estimate the lithology parameter value and lithology parameter interval of the formation while drilling; The determination submodule is used to obtain the distribution characteristics of the lithology parameters of the formation while drilling based on the lithology parameter values ​​and lithology parameter intervals.

11. An electronic device, characterized in that: include: a processor coupled to the memory; The memory is used to store computer programs; The processor is configured to execute the computer program stored in the memory, so that the electronic device executes the method according to any one of claims 1 to 7.

12. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a program or an instruction, and when the program or the instruction is executed on a computer, the computer is caused to perform the method according to any one of claims 1 to 7.

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