Automatic correction and connection method of complex stratum sequence considering occurrence and topology

Abstract

The application provides a complex stratum sequence correction and connection method considering occurrence and topology. The application makes full use of horizontal distribution characteristics of strata formed by multiple drill holes, and corrects stratum sequence through occurrence constraint. In addition, the application also makes full use of vertical distribution characteristics of drill holes to consider the topological relationship between strata, and intuitively and conveniently connects stratum sequence through a directed graph. The application provides a complex stratum sequence correction and connection method considering occurrence and topology, which combines a directed graph and occurrence constraint, and simply and intuitively automatically connects stratum sequence, thereby providing a basis for stratum connection in three-dimensional geological modeling. In addition, the application solves the ambiguity of the insertion position of a zero-thickness layer in stratum sequence, reduces the error rate of stratum correspondence, reduces the workload of manual intervention in the modeling process, and thereby improves the modeling speed and accuracy.

Description

Technical Field

[0001] This invention relates to the adjustment and connection of data in the field of geology, and more particularly to an automatic correction and connection method for complex stratigraphic sequences that takes into account occurrence and topology. Background Technology

[0002] In the process of constructing 3D geological models, phenomena such as stratigraphic inversion, folding, and jointing caused by complex geological tectonic movements often fail to adequately consider the stratigraphic correspondence between adjacent boreholes in traditional stratigraphic sequence determination and connection methods, leading to unreasonable stratigraphic connections in the 3D model. However, the rationality of stratigraphic sequence connections directly affects the accuracy of geological profiles constructed from boreholes and also directly impacts the rationality of geological models constructed using stratigraphic sequence-dependent modeling methods. Currently available stratigraphic sequence connection methods mainly include classification and processing of complex stratigraphic situations (stratigraphic inversion, missing, duplicate, etc.) and recursive sub-borehole methods.

[0003] Currently, the widely used borehole sequence connection method classifies and handles complex stratigraphic situations (such as stratigraphic inversion, missing layers, and duplication). Specifically, it first identifies special cases such as inversion, missing layers, and duplication in borehole strata, distinguishing them from normal cases within the same lithology. Second, by adding zero-thickness layers, it unifies the borehole stratigraphic sequence, establishing correspondences between borehole strata and reducing the error rate in connecting stratigraphic lines with complex situations. This method can resolve simple inversion cases, but for complex inversion phenomena, there are ambiguities regarding the insertion location of zero-thickness layers and the determination of inverted strata.

[0004] The borehole sequence stratigraphic connection method can also be implemented using the sub-bore recursive approach. Utilizing surface modeling methods, the stratigraphic sequence is determined from bottom to top, and a three-dimensional stratigraphic model is created layer by layer. This approach is suitable for complex geological structures such as stratigraphic pinch-outs, stratigraphic overburdens, and lenses, but it is less effective in determining stratigraphic sequences and handling cases containing inverted strata.

[0005] In general, existing stratigraphic linking methods mostly rely on the spatial relationships of borehole sampling points, introducing methods such as "sub-boreholes" and "zero-thickness layers" for stratigraphic division. These methods are ineffective in addressing the ambiguity of zero-thickness layer insertion locations and the ambiguity of inverted strata determination, and their algorithms are complex and lack intuitiveness and directness in expressing stratigraphic sequence links. Furthermore, existing methods often fully utilize the vertical distribution characteristics of boreholes to consider the distribution range, spatial relationships, and topological relationships of boreholes and strata, failing to fully leverage the horizontal distribution characteristics of strata formed by multiple boreholes to consider stratigraphic attitude information. Therefore, for borehole data containing complex strata such as inverted, missing, and duplicated strata, and with significant differences in stratigraphic attitude, the above techniques are insufficient for simple and intuitive automatic stratigraphic sequence linking, and cannot adequately resolve issues such as the ambiguity of zero-thickness layer insertion locations and the ambiguity of complex strata determination. Summary of the Invention

[0006] Based on the technical problems mentioned in the background section, this invention provides a method for correcting and connecting complex stratigraphic sequences considering attitude and topology. It introduces the concept of a directed graph, comprehensively considers stratigraphic attitude and topological relationships, and automatically corrects and connects stratigraphic sequences applicable to complex strata including inversions, facilitating subsequent modeling algorithms. The technical means employed in this invention are as follows:

[0007] A sequence correction and connection method for complex strata considering attitude and topology, comprising the following steps:

[0008] Step 1: Obtain M for each stratum i The set of points P i The set of points from all strata constitutes the total set of points P = {P} i ,i=1,2,...,l};

[0009] Step 2: Calculate the point set P for each stratum by introducing principal component analysis. i L's occurrence i ={L i1 ,L i2 ,L i3}, half-length H i ={H i1 H i2 H i3 Let the set of attitudes of all strata be L = {L i The set of half-lengths of all strata, i = 1, 2, ..., m, is H = {H}. i ,i=1,2,...,m};

[0010] Step 3: Half-length H i Stratigraphic sequence S = {S} is obtained in ascending order. i ,i=1,2,...,m};

[0011] Step 4: Consider stratigraphic sequence correction and connection based on attitude and topology; cycle through the stratigraphic sequence S to find the current stratigraphic number S. i (i <m);

[0012] Step 5: Calculate the current stratigraphic number S i Fitting plane i ={N i D i};

[0013] Step 6: Sequence stratigraphy correction based on attitude constraints, using the current stratigraphic number S i Occurrence L i Reclassification of stratigraphy S j (i <j<m);

[0014] Step 7: Construct a directed graph G(V,E) of stratigraphic contact relationships;

[0015] Step 8: Determine whether the directed graph G(V,E) is a directed acyclic graph using the depth-first search algorithm for directed graphs; if G(V,E) is not a directed acyclic graph, then let S... i =S i+1 Return to step 5; if G(V,E) is a directed acyclic graph, then proceed to step 9.

[0016] Step 9: Topological sorting to obtain the topological sequence T = {Ti, i = 1, 2, ..., m}.

[0017] Furthermore, in step 1, a set of boreholes Z = {Z} is defined as a plurality of boreholes. i In the case of boreholes i = 1, 2, ..., n, each borehole has several borehole sections J. zi ={J ij ,j=1,2,...,k};The borehole set Z contains a total of m formations M={M i {i = 1, 2, ..., m}, where i represents the stratum number; for each stratum M... i Circulate the drilling process for each hole Z i Each drilling section J ij If the drilling section J ij The stratigraphic name is equal to stratigraphic M. i Then calculate the borehole section J. ij The center point p is placed in the formation M. i The set of points P i middle.

[0018] Furthermore, step 3 includes the following steps:

[0019] Step 3.1: Calculate M for each formationi The set of points P i half length H i ={H i1 H i2 H i3 The minimum value of} is taken as the M value of this stratum. i minimum half length H i,min =min(H i1 H i2 H i3 );

[0020] Step 3.2: Use the bubble sort algorithm to find the minimum half-length H of all strata. i,min Sort the strata in ascending order to obtain the minimum half-length set H of all strata in ascending order. + ={H i,min ,i=1,2,...,m};

[0021] Step 3.3: Establish an empty set of stratigraphic sequences S = {S i The smallest half-length set H, i = 1, 2, ..., m, ordered by ascending order of all strata. + The order of H + The corresponding stratigraphic number i is added to set S, i.e., S i =i.

[0022] Furthermore, in step 5, the stratigraphic number S to be divided is obtained from the set of attitudes of all stratigraphic strata L. i The corresponding set of attitudes L i ={L i1 ,L i2 ,L i3} and the point set P i Fitting plane i normal vector N i =L i3 = {A, B, C}, where A, B, C represent vectors N and N respectively. i Components in the x, y, and z directions; known set of points P i All points in the set lie on the fitting plane, and the distance D between the fitting plane and the origin is... i Calculate based on the spatial plane equation Ax + By + Cz + D = 0.

[0023] Furthermore, step 6 includes the following steps:

[0024] Step 6.1: Extract S j (j>i) set of points P j Obtain the stratigraphic number S from the point set P of all strata. j The corresponding set of points P j ; Obtain the stratigraphic number S of the subdivided strataj stratigraphic name j Define a new stratum name: new_name j Let the new stratigraphic name be equal to name. j Add the current stratigraphic number S i ;

[0025] Step 6.2: Calculate set P j The middle is located in Plane i The number of points on the positive and negative sides, Num1 and Num2; let Num1 = 0, Num2 = 0; cyclic set P j Given a point p = (x, y, z) in the space plane equation function f(p) = Ax + By + Cz + D; if f(p) is greater than 0, then Num1 is incremented by 1; if f(p) is less than 0, then Num2 is incremented by 1.

[0026] Step 6.3: Determine if Num1 > 0 and Num2 > 0; if not, let S j =S j+1 Return to step 6.1; if so, set Plane i The negative side point corresponds to borehole section J. ij Assign a new stratigraphic name new_name j S j =S j+1 Return to step 6.1.

[0027] Furthermore, step 7 also includes the following steps:

[0028] Step 7.1: Recalculate the total number of formations m in borehole set Z; borehole set Z contains a total of m formations M = {M i {i = 1, 2, ..., m}, where i represents the stratum number;

[0029] Step 7.2: Define a directed graph G(V,E) with a total of m nodes; let the set of nodes of the directed graph be V = S = {S i ,i=1,2,...,m};

[0030] Step 7.3: Cycle through each drill hole Z i Each drilling section J ij (j>0);

[0031] Step 7.4: Obtain the borehole section J ij With its drilling section J ij-1 The corresponding stratigraphic number S j and S j-1 And set edge Ei = j-1 ,S j >Add to edge set E = {E​i ,i=1,2,...,n}.

[0032] Furthermore, in step 9, the Kosaraju-Sharir algorithm is used to perform a topological sort on the directed graph G(V,E).

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] This invention fully utilizes the horizontal distribution characteristics of strata formed by multiple boreholes, and corrects stratigraphic sequences through attitude constraints. Furthermore, it also takes full advantage of the vertical distribution characteristics of the boreholes to consider the topological relationships between strata, and connects stratigraphic sequences intuitively and conveniently using directed graphs. This invention provides a method for correcting and connecting complex stratigraphic sequences considering both attitude and topology. Combining directed graphs and attitude constraints, it enables simple and intuitive automatic connection of stratigraphic sequences, providing a basis for stratigraphic connections in 3D geological modeling.

[0035] Compared with existing technologies, the technical solution proposed in this invention uses attitude as a constraint to correct the strata and introduces a directed graph to determine the stratigraphic sequence. This can make full use of the horizontal distribution characteristics of the strata formed by multiple boreholes, as well as the vertical distribution characteristics of the boreholes to consider the topological relationships between strata. It can automatically connect the stratigraphic sequence in a simple and intuitive way, solve the ambiguity of the insertion position of zero-thickness layer in the stratigraphic sequence, reduce the error rate of strata correspondence, reduce the amount of manual intervention in the modeling process, thereby improving the modeling speed and accuracy, and providing a basis for stratigraphic connection in three-dimensional geological modeling. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a flowchart of a method for sequence correction and connection of complex strata considering attitude and topology according to the present invention. Detailed Implementation

[0038] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0039] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0040] like Figure 1 As shown, the present invention provides a method for sequence correction and connection of complex strata considering attitude and topology, comprising the following steps:

[0041] Step 1: Obtain M for each formation i The set of points P i The set of points from all strata constitutes the total set of points P = {P} i ,i=1,2,...,l};A set of boreholes Z={Z i In the case of boreholes i = 1, 2, ..., n, each borehole has several borehole sections J. zi ={J ij The borehole set Z contains m formations, M = {M,j = 1, 2, ..., k}. i {m, i = 1, 2, ..., m}, where i is the stratum number. For each stratum M... i Circulate the drilling process for each hole Z i Each drilling section J ij If the drilling section J ij The stratigraphic name is equal to stratigraphic M. i Calculate the borehole section J ij The center point p is placed in the formation M. i The set of points P i middle.

[0042] Step 2: PCA calculates the point set P for each formation. i L's occurrence i ={L i1 ,L i2 ,L i3}, half-length H i ={H i1 H i2 H i3}; The set of attitudes of all strata is L = {Li The set of half-lengths of all strata, i = 1, 2, ..., m, is H = {H}. i In this application, Principal Component Analysis (PCA) is introduced to calculate the point set P, where i = 1, 2, ..., m. i The three main directions L i1 ,L i2 ,L i3 And the corresponding half-length H i1 H i2 H i3 ;

[0043] Step 3: H i Stratigraphic sequence S = {S} is obtained in ascending order. i The process includes the following steps: (i = 1, 2, ..., m)

[0044] Step 3.1: Calculate M for each formation i The set of points P i half length H i ={H i1 H i2 H i3 The minimum value of} is taken as the M value of this stratum. i minimum half length H i,min =min(H i1 H i2 H i3 );

[0045] Step 3.2: Use the bubble sort algorithm to find the minimum half-length H of all strata. i,min Sort the strata in ascending order to obtain the minimum half-length set H of all strata in ascending order. + ={H i,min ,i=1,2,...,m};

[0046] Step 3.3: Establish an empty set of stratigraphic sequences S = {S i The smallest half-length set H, i = 1, 2, ..., m, ordered by ascending order of all strata. + The order of H + The corresponding stratigraphic number i is added to set S, i.e., S i =i.

[0047] Step 4: Consider stratigraphic sequence correction and connection based on attitude and topology. Cyclicly recursively analyze the stratigraphic sequence S to find the current stratigraphic number S. i (i <m):

[0048] Step 5: Calculate S i Fitting plane i ={Ni , D i}; obtaining the divided stratum number S from the occurrence set L of all strata i corresponding occurrence set L i = {L i1 , L i2 , L i3} and point set P i . Fitting plane Plane i normal vector N i = L i3 = {A, B, C}, wherein A, B, and C are the components of vector N i in three x, y and z directions. It is known that all points in point set P i are all located on the fitting plane, and the distance D between the fitting plane and the origin i can be calculated according to the space plane equation Ax+By+Cz+D=0.

[0049] Step 6: Corrected stratigraphic sequence based on occurrence constraints, use S i occurrence L i redivide stratum S j (i<j<m); circulate through the stratum sequence S to find the divided stratum number S j (i<j<m), which specifically comprises the following steps:

[0050] Step 6.1: Extract S j (j>i) point set P j ;

[0051] obtaining the corresponding point set P of the divided stratum number S from the point set P of all strata j corresponding point set P j . Obtaining the stratum name name of the divided stratum number S j stratum name name j . Defining a new stratum name new_name j , and making it equal to name j plus the current stratum number S i .

[0052] Step 6.2: Calculate the number of points in P j that are respectively located on the positive side and negative side of Plane i , which are denoted as Num1 and Num2;

[0053] Let Num1=0 and Num2=0. Circulate through the point p=(x,y,z) in set P j , substitute p into the space plane equation function f(p)=Ax+By+Cz+D. If f(p) is greater than 0, increment Num1 by 1; if f(p) is less than 0, increment Num2 by 1.

[0054] Step 6.3: Are Num1 > 0 and Num2 > 0? If not, let S j =S j+1 Return to step 6.1; if so, set Plane i The negative side point corresponds to borehole section J. ij Assign a new stratigraphic name new_name j , making S j =S j+1 Return to step 6.1;

[0055] Step 7: Construct a directed graph G(V,E) of the stratigraphic contact relationships; specifically including the following steps:

[0056] Step 7.1: Recalculate the total number of formations m in borehole set Z. Borehole set Z contains a total of m formations, M = {M...} i ,i=1,2,...,m}, where i is the stratum number.

[0057] Step 7.2: Define a directed graph G(V,E) with a total of m nodes. Let the set of nodes of the directed graph be V = S = {S... i ,i=1,2,...,m};

[0058] Step 7.3: Cycle through each drill hole Z i Each drilling section J ij (j>0):

[0059] Step 7.4: Obtain the borehole section J ij With its drilling section J ij-1 The corresponding stratigraphic number S j and S j-1 And set edge Ei = j-1 ,S j >Add to edge set E = {E i ,i=1,2,...,n}.

[0060] Step 8: Determine if it is a directed acyclic graph (DAG);

[0061] Step 8.1: In this application, the depth-first search (DFS) algorithm for directed graphs is used to determine whether the directed graph G(V,E) is a directed acyclic graph (DAG).

[0062] Step 8.2: If G(V,E) is not a DAG, let S i =S i+1 If yes, return to step 5; otherwise, proceed to step 9.

[0063] ​Step 9: Topological sorting to obtain the topological sequence T = {Ti, i = 1, 2, ..., m}; The Kosaraju-Sharir algorithm is used to perform topological sorting on the directed graph G(V, E) to obtain the topological sequence T = {Ti, i = 1, 2, ..., m};

[0064] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. In the above embodiments of the present invention, the descriptions of each embodiment have their own emphasis; parts not described in detail in a certain embodiment can be referred to in the relevant descriptions of other embodiments. It should be understood that the disclosed technical content in the several embodiments provided in this application can be implemented in other ways.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for sequence stratigraphic correction and connection of complex strata considering attitude and topology, characterized in that, Includes the following steps: Step 1: Obtain each stratum M i set of points P i The set of points from all strata constitutes the total set of points. P={P i , i=1, 2,...,l} ; Step 2: Calculate the point set for each stratum by introducing principal component analysis. P i The state of birth L i ={L i1 ,L i2 ,L i3 } Half-length H i ={H i1 ,H i2 ,H i3 } Let the set of attitudes of all strata be . L={L i , i=1,2,...,m} The half-length set of all strata is H={H i , i=1,2,...,m} ; Step 3: Use the ascending order of the shortest half-length of each stratum as the stratigraphic sequence. S={S i , i=1,2,...,m} ; Step 4: Cyclic Stratigraphic Sequence S Find the current stratigraphic number S i (i <m) ; Step 5: Calculate the current stratigraphic number S i Fitting plane Plane i ={N i ,D i } In step 5, the attitude of all strata is collected. L Obtain the subdivided stratigraphic number S i The corresponding set of attitudes L i ={L i1 ,L i2 ,L i3 } and point sets P i Fitting plane Plane i normal vector N i =L i3 ={A,B,C} ,in, A,B,C Representing vectors respectively N i Components in the x, y, and z directions; known set of points P i All points in the set lie on the fitting plane, and the distance between the fitting plane and the origin is... D i According to the equation of the space plane Ax+By+ Cz+D=0 calculate; Step 6: Stratigraphic sequence correction based on attitude constraints: using the current stratigraphic number S i Occurrence L i Reclassification of stratigraphy S j (i <j <m) Step 6 includes the following steps: Step 6.1: From the set of points of all strata P Obtain the subdivided stratigraphic number S j The corresponding set of points P j ; Obtain the stratigraphic number S of the subdivided strata j stratigraphic names name j Define new stratigraphic names new_name j Let the new stratigraphic name equal to name j Add current stratigraphic number S i ; Step 6.2: Calculate the set P j The middle are located in Plane i The number of points on the positive and negative sides, Num1 and Num2; set Num1=0, Num2=0; cyclic set. P j Points in p=(x',y',z') ,Will p Substituting the spatial plane equation function f(p) = Ax + By + Cz + D ;if f (p) If it is greater than 0, then Num1 is incremented by 1; if f(p) If the value is less than 0, increment Num2 by 1; Step 6.3: Determine if Num1 > 0 and Num2 > 0; if not, let S j =S j+1 Return to step 6.1; if so, Plane i Negative side point corresponds to the borehole section J ij Assigning new stratigraphic names new_name j ,make S j =S j+1 Return to step 6.1; Step 7: Construct a directed graph based on the stratigraphic contact relationships. G(V, E) ; Step 8: Determine the directed graph using the depth-first search algorithm. G(V, E) Is it a directed acyclic graph? If so... G(V, E) If it is not a directed acyclic graph, then let S i =S i+1 Return to step 5; if G(V, E) If it is a directed acyclic graph, then proceed to step 9; Step 9: Obtain the topological sequence by topological sorting. T={Ti, i=1,2,...,m} .

2. The method for sequence stratigraphic correction and connection of complex strata considering attitude and topology according to claim 1, characterized in that, In step 1, a set of boreholes is formed by several boreholes. Z={Z i , i=1,2,...,n} Each borehole has several borehole sections. J zi ={J ij , j=1,2,...,k} Drilling assembly Z A total of m strata M={M i , i=1,2,...,m} , i Indicates the stratum number; for each stratum M i Circulate through each drill hole Z i Each drill section J ij If the drilling section J ij The stratigraphic name is equal to the stratigraphic name. M i Then calculate the borehole section. J ij center point p and the center point p Placed into the stratum M i set of points P i middle.

3. The method for sequence stratigraphic correction and connection of complex strata considering attitude and topology according to claim 1, characterized in that, Step 3 includes the following steps: Step 3.1: Calculate each stratum M i set of points P i half length H i ={H i1 ,H i2 ,H i3 } The minimum value is used as the stratum. M i minimum half length H i,min =min(H i1 ,H i2 ,H i3 ) ; Step 3.2: Use the bubble sort algorithm to find the minimum half-length of all strata. H i,min Sort in ascending order to obtain the minimum half-length set of all strata in ascending order. H + ={H i,min , i=1,2,...,m} ; Step 3.3: Establish an empty set of stratigraphic sequences S={S i , i=1,2,...,m} The minimum half-length set in ascending order of all strata. H + The order will H + Corresponding stratigraphic number i Add to collection S In, that is S i = i .

4. The method for sequence correction and connection of complex strata considering attitude and topology according to claim 1, characterized in that, Step 7 also includes the following steps: Step 7.1: Recalculate the borehole set Z Total number of strata m; Borehole set Z A total of m strata M={M i , i=1,2,..., m} , i Indicates the stratigraphic number; Step 7.2: Define the directed graph G(V, E) The total number of nodes in the directed graph is m; let the node set of the directed graph be m. V=S={S i , i= 1,2,...,m} ; Step 7.3: Repeat the drilling process for each hole. Z i Each drill section J ij (j>0) ; Step 7.4: Obtain the borehole section J ij With the drilled section J ij-1 Corresponding stratigraphic number S j and S j-1 and the edge E i =< S j-1 ,S j >Add to edge set E={E i ,i=1,2,...,n} middle 。 5. The method for sequence stratigraphic correction and connection of complex strata considering attitude and topology according to claim 1, characterized in that, In step 9, the Kosaraju-Sharir algorithm is used to process the directed graph. G(V, E) Perform a topological sort.

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