Shale gas structural geological model correction method based on well trajectory and layered data

Abstract

The application discloses a shale gas structural geological model correction method based on a wellbore trajectory and layered data, and comprises the following steps: constructing a stratum thickness model; obtaining small-layer apparent thickness plane data; establishing a passing mode of the wellbore trajectory in each small layer; calculating specific spatial positions of small-layer boundaries by the established passing mode of the wellbore trajectory in each small layer and in combination with the small-layer apparent thickness plane data; judging whether the spatial position result is continuous and smooth according to the calculated small-layer boundary spatial position result; and adjusting thickness data of the small-layer apparent thickness plane data and depth data of the specific spatial positions of the small-layer boundaries when the spatial position result is not smooth. The geological model correction method can better utilize horizontal well related information to quickly and efficiently process batch well data, thereby correcting seismic horizons, making the structural model well match the spatial position relationship of the horizontal well passing, and providing reliable data basis for the next attribute modeling and numerical simulation.

Description

Technical Field

[0001] This invention relates to the field of shale gas development, and specifically to a method for correcting shale gas structural geological models based on wellbore trajectory and stratification data. Background Technology

[0002] Currently, research on structural geological modeling technology mainly focuses on conventional oil and gas reservoirs such as clastic rocks and carbonates, while shale gas reservoirs are still in their early stages, and the relevant modeling methods still adopt conventional oil and gas reservoir modeling approaches and methods. Shale gas reservoirs generally adopt horizontal well development methods, and structural geological modeling is more difficult when utilizing horizontal well information. Conventional seismic stratigraphic well calibration methods are all based on vertical wells, which are not very applicable to horizontal wells. In most cases, manual adjustments are required. Therefore, there is an urgent need to develop a calibration method that can fully utilize relevant data from horizontal wells for rapid and efficient batch processing. Summary of the Invention

[0003] The main objective of this invention is to provide a method for correcting shale gas structural geological models based on wellbore trajectory and stratification data, aiming to accurately create a high-precision structural geological model that perfectly matches the horizontal well path throughout the region.

[0004] To achieve the above objectives, this invention provides a method for correcting shale gas structural geological models based on wellbore trajectory and stratification data, comprising the following steps:

[0005] A formation thickness model was constructed based on horizontal well stratification data and seismic stratigraphic data.

[0006] Based on the formation thickness model, scatter plot data of the apparent thickness of the sub-layers are obtained. Combined with the seismic response plane characteristic distribution constraint scatter plot interpolation, the apparent thickness plane data of the sub-layers are obtained.

[0007] Based on wellbore trajectory and horizontal well stratification data, the traversal pattern of wellbore trajectory in each sub-layer is established and simplified into a geometric function relationship;

[0008] By establishing the wellbore trajectory's travel pattern across each sub-layer, and combining it with the sub-layer apparent thickness plane data, the specific spatial location of each sub-layer interface is calculated.

[0009] Based on the calculated spatial location results of the sub-layer interfaces, determine whether the spatial location results are continuous and smooth;

[0010] When the spatial location results are not smooth, adjust the thickness data of the sub-layer apparent thickness plane data and the depth data of the specific spatial location of each sub-layer interface.

[0011] Preferably, after the step of determining whether the spatial position result is continuous and smooth based on the calculated spatial position result of the small-layer interface, the method further includes:

[0012] When the spatial location results are smooth, output the required sub-layer results to correct the seismic horizon and improve the reasonable and reliable structural model.

[0013] Preferably, in the step of constructing a formation thickness model based on horizontal well layering data and seismic horizon data, when the lateral variation of formation thickness is greater than a preset variation rate, the small layer is treated with equal thickness; when the lateral variation of formation thickness is greater than a preset variation rate, the apparent thickness of each small layer is estimated by using the horizontal well deviated well traversing the formation mode, through layering data and wellbore trajectory.

[0014] Preferably, the apparent thickness of each sub-layer is estimated using the following formula based on layered data and wellbore trajectory:

[0015] ;

[0016] In the formula, The elevation difference between the top and bottom interfaces of the formation and the intersection of the wellbore trajectory; The dip angle of the strata between the strata points; The difference in depth between the stratified points; The apparent thickness of the formation at the stratification point is given. When the plus sign is used in the formula, the wellbore trajectory direction is the same as the formation dip, and when the minus sign is used, the wellbore trajectory direction is opposite to the formation dip.

[0017] Preferably, in the step of establishing the wellbore trajectory's travel pattern in each sub-layer based on the wellbore trajectory and horizontal well stratification data, and simplifying it into a geometric function relationship, when determining the contact relationship between the preceding and following strata of the current formation, if the preceding and following strata are the same, it indicates that the wellbore trajectory has not penetrated the current formation, and is a travel pattern of penetrating out and returning to the original formation; if the preceding and following strata are different, it indicates that the wellbore trajectory penetrates the current formation, and is a penetrating travel pattern.

[0018] Preferably, the well trajectory traversal patterns in each sub-layer include two well trajectory traversal patterns: one where the A and B layering points corresponding to the formations do not contact the same formation, and the other where the A and B layering points corresponding to the formations contact the same formation.

[0019] Preferably, when the A and B layering points corresponding to the strata do not contact the same strata,

[0020] The specific location of the well trajectory within a sub-layer is calculated using the following formula:

[0021] ;in, , ;

[0022] In the above formula, This is the vertical distance from the wellbore location to the top or bottom of the formation; The thickness of the strata; , , These represent the depth measurements corresponding to the wellbore trajectory points and the stratification points A and B, respectively. When the formations contacted by points A and B are from newest to oldest, this represents the distance from the bottom of the formation; conversely, it represents the distance from the top of the formation.

[0023] Preferably, when the A and B layering points corresponding to the strata are in contact with the same strata,

[0024] The specific location of the well trajectory within a sub-layer is calculated using the following formula:

[0025] ;in, , ;

[0026] When the strata that points A and B touch are from newest to oldest, it represents the distance from the bottom of the stratum; conversely, it represents the distance from the top of the stratum.

[0027] Preferably, the elevation depth of each sub-layer interface is calculated using the following formula based on the specific location of the well trajectory within the sub-layer:

[0028] ;

[0029] In the formula, This represents the elevation depth of a specific sub-layer corresponding to the measuring point. The elevation and depth of the measuring point. The thickness of the stratum from the location of the measuring point to a certain sub-layer.

[0030] Preferably, after calculating the spatial location of the sublayer interface, the results are smoothed by the sublayer elevation depth corresponding to all measuring points of the horizontal well, so as to control the spatial location of the sublayer interface within a preset range.

[0031] The shale gas structural geological model correction method based on wellbore trajectory and stratification data proposed in this invention can make good use of horizontal well related information for rapid and efficient batch well data processing, thereby correcting seismic horizons and enabling the structural model to well match the spatial positional relationship of horizontal wells, providing a reliable data foundation for subsequent attribute modeling and numerical simulation. Attached Figure Description

[0032] Figure 1 This is a flowchart illustrating the shale gas structural geological model correction method based on wellbore trajectory and stratification data according to the present invention.

[0033] Figure 2 This is a model diagram of the formation thickness in the inclined well section when the formation dip is the same as the drilling direction in the shale gas structural geological model correction method based on wellbore trajectory and stratification data of the present invention.

[0034] Figure 3 This is a model diagram of the formation thickness in the deviated well section when the formation dip is opposite to the drilling direction in the shale gas structural geological model correction method based on wellbore trajectory and stratification data of this invention.

[0035] Figure 4 This is a diagram of the formation crossing pattern of the horizontal well trajectory in the formation crossing model of the shale gas structural geological model correction method based on wellbore trajectory and stratification data in this invention.

[0036] Figure 5 This is a diagram of the formation crossing pattern of the horizontal well trajectory in the shale gas structural geological model correction method based on wellbore trajectory and stratification data in this invention, when the formation has not been penetrated.

[0037] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0038] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0039] In this preferred embodiment, refer to Figure 1 A method for correcting shale gas structural geological models based on wellbore trajectory and stratification data includes the following steps:

[0040] Step S1: Construct a formation thickness model based on horizontal well layering data and seismic horizon data;

[0041] Step S2: Obtain the scatter data of the apparent thickness of the sub-layer based on the stratum thickness model, and combine it with the scatter interpolation constrained by the seismic response plane characteristic distribution to obtain the plane data of the apparent thickness of the sub-layer.

[0042] Step S3: Based on the wellbore trajectory and horizontal well stratification data, establish the wellbore trajectory's movement pattern across each sub-layer, simplifying it into geometric function relationships (e.g., ...). Figure 2 and Figure 3 (as shown)

[0043] Step S4: By establishing the wellbore trajectory's travel pattern in each sub-layer and combining it with the sub-layer apparent thickness plane data, the specific spatial location of each sub-layer interface is calculated.

[0044] Step S5: Based on the calculated spatial location results of the sub-layer interface, determine whether the spatial location results are continuous and smooth; if the spatial location results are not smooth, execute step S6 and return to execute step S5 until the spatial location results are continuous and smooth.

[0045] Step S6: Adjust the thickness data of the sub-layer thickness plane data and the depth data of the specific spatial location of each sub-layer interface.

[0046] Step S5 is followed by:

[0047] If the spatial location result is not smooth, proceed to step S7;

[0048] Step S7: Output the results of the sub-layers that meet the requirements, which are used to correct the seismic horizons and improve the reasonable and reliable structural model.

[0049] In the updated structural model, the wellbore data and seismic horizons are perfectly matched.

[0050] In step S1, when the lateral change in formation thickness is greater than the preset change rate, the small layer is treated as equal thickness; when the lateral change in formation thickness is greater than the preset change rate, the apparent thickness of each small layer is estimated by using the horizontal well-deflected well formation traversal mode, through layer data and wellbore trajectory.

[0051] Specifically, the apparent thickness of each sub-layer is estimated using the following formula based on stratified data and wellbore trajectory:

[0052] (1)

[0053] In the formula, The elevation difference between the top and bottom interfaces of the formation and the intersection of the wellbore trajectory; The dip angle of the strata between the strata points; The difference in depth between the stratified points; This represents the apparent thickness of the formation at the stratification point. The plus sign in the formula indicates that the wellbore trajectory direction is the same as the formation dip (e.g., ...). Figure 2 As shown), when the minus sign is used in the formula, it indicates that the wellbore trajectory direction is opposite to the formation dip (e.g. Figure 3 (As shown).

[0054] In step S2, conventional seismic response characteristics usually reflect the impedance difference between upper and lower layers at the stratum interface, which is difficult to establish a direct relationship with the stratum thickness. Currently, it can only be controlled by artificially adding control points.

[0055] In step S3, when determining the contact relationship between the preceding and following strata of the current formation, if the preceding and following strata are the same, it indicates that the wellbore trajectory has not penetrated the current formation, and it is a traversal pattern of penetrating out and then penetrating back to the original formation (e.g. Figure 5 As shown); if the preceding and following strata are different, it indicates that the wellbore trajectory traverses the current stratum, representing a traversing pattern (e.g. Figure 4 (As shown).

[0056] To facilitate the calculation of Boolean values ​​0 and 1 in the program, a stratum can be defined as 0 if all its adjacent strata are the same, and 1 otherwise.

[0057] In step S4, the established wellbore trajectory traversal patterns in each sub-layer include two types of wellbore trajectory traversal patterns: the A and B layer points corresponding to the formations do not contact the same formations, and the A and B layer points corresponding to the formations contact the same formations.

[0058] Specifically, when the A and B stratification points corresponding to the strata do not contact the same strata,

[0059] The specific location of the well trajectory within a sub-layer is calculated using the following formula:

[0060] ;in, , (2)

[0061] In the above formula, It is the vertical distance from the wellbore location to the top or bottom of the formation; It refers to the thickness of the strata; , , These are the depth measurements corresponding to the wellbore trajectory points and the layer points A and B, respectively; in formula (2), when the formations contacted by points A and B are from new to old, it represents the distance from the bottom of the formation; otherwise, it represents the distance from the top of the formation.

[0062] When the A and B layering points corresponding to the strata are in contact with the same strata...

[0063] The specific location of the well trajectory within a sub-layer is calculated using the following formula:

[0064] ;in, , (3)

[0065] In formula (3), when the strata that A and B are in contact with are from newest to oldest, it represents the distance from the bottom of the stratum; conversely, it represents the distance from the top of the stratum.

[0066] The elevation depth of each sub-layer boundary is calculated based on the specific location of the well trajectory within the sub-layer using the following formula:

[0067] ;

[0068] In the formula, This represents the elevation depth of a specific sub-layer corresponding to the measuring point. It refers to the elevation and depth of the measuring point. The thickness of the stratum from the location of the measuring point to a certain sub-layer.

[0069] In step S4, the spatial location of each measuring point (wellbore trajectory) within the stratum is calculated based on the different travel patterns of the well in each formation segment. The apparent thickness of each sub-layer corresponding to the coordinates of each measuring point is then read, thereby calculating the elevation depth corresponding to the interface of each sub-layer at each measuring point. The ratio of elevation depth to sounding depth at adjacent points of a certain sub-layer is calculated (derivative of elevation with respect to sounding depth). If the slope value is within the allowable range, it is not modified. If the requirements are not met, the slope of the preceding and following points is checked for consistency (second derivative of elevation with respect to sounding depth). If they are inconsistent and exceed the allowable range, the elevation value is iteratively processed until the requirements are met. The adjusted elevation value is then used to recalculate the thickness of each sub-layer corresponding to that point.

[0070] In step S5, based on the calculated spatial location results of the sub-layer interface, a smoothing process is performed using the sub-layer elevation depths corresponding to all measuring points of the horizontal well, controlling the spatial location results of the sub-layer interface within a preset range. This smoothing process involves differentiating the elevation depth with respect to the sounding depth and taking its second derivative, then controlling the result within a certain range.

[0071] The shale gas structural geological model correction method based on wellbore trajectory and stratification data proposed in this invention can make good use of horizontal well related information for rapid and efficient batch well data processing, thereby correcting seismic horizons and enabling the structural model to well match the spatial positional relationship of horizontal wells, providing a reliable data foundation for subsequent attribute modeling and numerical simulation.

[0072] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for correcting shale gas structural geological models based on wellbore trajectory and stratification data, characterized in that, Includes the following steps: A formation thickness model was constructed based on horizontal well stratification data and seismic stratigraphic data. Based on the formation thickness model, scatter plot data of the apparent thickness of the sub-layers are obtained. Combined with the seismic response plane characteristic distribution constraint scatter plot interpolation, the apparent thickness plane data of the sub-layers are obtained. Based on wellbore trajectory and horizontal well stratification data, the traversal pattern of wellbore trajectory in each sub-layer is established and simplified into a geometric function relationship; By establishing the wellbore trajectory's travel pattern across each sub-layer, and combining it with the sub-layer apparent thickness plane data, the specific spatial location of each sub-layer interface is calculated. Based on the calculated spatial location results of the sub-layer interfaces, determine whether the spatial location results are continuous and smooth; When the spatial location results are not smooth, adjust the thickness data of the apparent thickness plane data of each sub-layer and the depth data of the specific spatial location of each sub-layer interface; in the step of establishing the wellbore trajectory's traversal pattern in each sub-layer based on the wellbore trajectory and horizontal well layering data, simplifying it into a geometric function relationship, when judging the contact relationship between the preceding and following formations of the current formation, if the preceding and following formations are the same, it indicates that the wellbore trajectory has not penetrated the current formation, which is a traversal pattern of penetrating out and returning to the original formation; if the preceding and following formations are different, it indicates that the wellbore trajectory has penetrated the current formation, which is a traversal pattern of penetration; the established wellbore trajectory traversal patterns in each sub-layer include two types of wellbore trajectory traversal patterns: the A and B layering points of the formation have different contact formations, and the A and B layering points of the formation have the same contact formation; when the A and B layering points of the formation have different contact formations... The specific location of the well trajectory within a sub-layer is calculated using the following formula: ;in, , ; In the above formula, This is the vertical distance from the wellbore location to the top or bottom of the formation; The thickness of the strata; , , These represent the depth measurements corresponding to the wellbore trajectory points and the strata points A and B, respectively. When the formations contacted by points A and B are from newest to oldest, this represents the distance from the bottom of the formation; conversely, it represents the distance from the top of the formation. When the formations contacted by strata points A and B are the same... The specific location of the well trajectory within a sub-layer is calculated using the following formula: ;in, , ; When the strata that points A and B touch are from newest to oldest, it represents the distance from the bottom of the stratum; conversely, it represents the distance from the top of the stratum. The elevation depth of each sub-layer boundary is calculated based on the specific location of the well trajectory within the sub-layer using the following formula: ； In the formula, This represents the elevation depth of a specific sub-layer corresponding to the measuring point. The elevation and depth of the measuring point. The thickness of the stratum from the location of the measuring point to a certain sub-layer.

2. The shale gas structural geological model correction method based on wellbore trajectory and stratification data as described in claim 1, characterized in that, The step of determining whether the spatial position result is continuous and smooth based on the calculated spatial position result of the small-layer interface further includes: When the spatial location results are smooth, output the required sub-layer results to correct the seismic horizon and improve the reasonable and reliable structural model.

3. The shale gas structural geological model correction method based on wellbore trajectory and stratification data as described in claim 1, characterized in that, The apparent thickness of each sub-layer is estimated using the following formula based on layered data and wellbore trajectory: ； In the formula, The elevation difference between the top and bottom interfaces of the formation and the intersection of the wellbore trajectory; The dip angle of the strata between the strata points; The difference in depth between the stratified points; The apparent thickness of the formation at the stratification point is given. When the plus sign is used in the formula, the wellbore trajectory direction is the same as the formation dip, and when the minus sign is used, the wellbore trajectory direction is opposite to the formation dip.

4. The shale gas structural geological model correction method based on wellbore trajectory and stratification data as described in any one of claims 1 to 3, characterized in that, Based on the calculated spatial location of the sublayer interface, the sublayer elevation depth corresponding to all measuring points of the horizontal well is used for smoothing to control the spatial location of the sublayer interface within a preset range.

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