Geosteering method and device for multi-layer stacked coalbed methane horizontal well

Abstract

The invention discloses a geosteering method and device for a multi-layer stacked coal bed gas horizontal well, and belongs to the technical field of horizontal well drilling. The geosteering method comprises the steps that based on adjacent well data, small-layer plane law diagrams of a target coal bed and a top plate and a bottom plate of the target coal bed are established, and the plane law diagrams comprise the plane law diagrams of double prevention and control lines; a target horizontal well three-dimensional geologic model is established, the position of the dual prevention and control line in the target horizontal well three-dimensional geologic model is obtained, and a target drilling reservoir is obtained; the design drilling track of the target horizontal well is obtained, in the drilling process of a drill bit, the positions of the double prevention and control lines in the three-dimensional geological model of the target horizontal well are updated according to obtained actual drilling data, whether the drill bit is ejected out or out of the bottom or not is judged through the double prevention and control lines, if yes, the drilling track is corrected, and the drilling track of the horizontal well can be guided in real time. Smooth drilling of the drill bit is guaranteed, drilling of non-reservoir sections and large fluctuation of a well track are reduced, and the drilling rate of a coalbed methane reservoir can be increased.

Description

Technical Field

[0001] The present invention relates to the field of horizontal well drilling, and in particular to a method and device for geosteering a multi-layered coalbed methane horizontal well. Background Art

[0002] At present, the common practice of geosteering of coalbed methane horizontal wells is to use modeling software to establish a three-dimensional geological model of the target horizontal well and design the horizontal well drilling trajectory. In the actual drilling process, the roof and floor of the coal seam are usually used as the upper and lower boundaries of the reservoir. Because the lithology of the roof and floor is significantly different from that of the coal seam, it is relatively easy to obtain logging cuttings for identification during drilling. Lithology changes can also be identified through gamma logging while drilling, and then it can be determined whether the drill bit is topped out or bottomed out, which can guide the drill bit to drill smoothly in the coal seam. However, this method often encounters more non-reservoir sections during the callback after the layer is pulled out, which greatly reduces the reservoir drilling rate, and will also have an adverse effect on the later fracturing section selection and fracturing effect, reducing resource utilization efficiency. Therefore, it is necessary to explore better layer control methods.

[0003] In the coalbed methane mining practice in a certain work area, it was found that short-term changes in the base level cycle occurred during the Taiyuan Formation coal deposition period, and two sets of thin carbonaceous mudstones with relatively stable and continuous thickness developed inside the target coal seam. Their lithological and electrical characteristics were significantly different from those of the coal seam. On this basis, considering combining these two sets of thin carbonaceous mudstones with the roof and floor of the coal seam, a multi-layer superimposed coalbed methane horizontal well geosteering method was designed. Summary of the invention

[0004] The present application provides a method and device for geo-steering of multi-layered coalbed methane horizontal wells, which is suitable for multi-layered coal reservoirs, can guide the drilling trajectory of coalbed methane horizontal wells in real time, control the relative position of the drill bit, ensure smooth drilling of the drill bit, reduce the drilling of non-reservoir sections and large fluctuations in the wellbore trajectory, and improve the drilling rate of the coalbed methane target drilling reservoir.

[0005] On the one hand, an embodiment of the present application provides a geosteering method for multi-layer stacked coalbed methane horizontal wells, comprising:

[0006] Based on the data from adjacent wells, a plane regularity map of the small layers of the target coal seam and its roof and floor is established; the small layers include a double control line and multiple small coal seams, wherein the double control line includes a first control line and a second control line, the first control line is the coal gangue layer located inside the target coal seam, and the target coal seam is divided into the multiple coal small layers; the second control line is the roof and the floor of the target coal seam;

[0007] Establishing a three-dimensional geological model of the target horizontal well, combining it with the plane regularity map of the small layer, obtaining the position of the dual control line in the three-dimensional geological model of the target horizontal well, and drilling into the reservoir with one of the multiple coal small layers as the target;

[0008] Acquiring a designed drilling trajectory of a target horizontal well according to the target drilling reservoir, including a landing stage drilling trajectory and a horizontal section drilling trajectory;

[0009] In a first process in which the drill bit drills according to the landing stage drilling trajectory, the position of the dual control line in the three-dimensional geological model of the target horizontal well is updated according to the first actual drilling data obtained, and the landing stage drilling trajectory is corrected according to the first actual drilling data and the updated position of the dual control line;

[0010] In the second process of the drill bit drilling according to the horizontal section drilling trajectory, the position of the double control line in the three-dimensional geological model of the target horizontal well is updated again according to the second actual drilling data obtained, and it is judged whether the drill bit is ejected or bottomed out according to the second actual drilling data and the position of the double control line after the update. If so, the horizontal section drilling trajectory is corrected.

[0011] Optionally, the step of establishing a planar regularity map of a target coal seam and its roof and floor based on data from adjacent wells includes:

[0012] Performing stratigraphic comparison based on well logging data and mud logging data of adjacent wells to establish a well-connected geological profile, wherein the number of adjacent wells is multiple, and the adjacent wells include drilled wells with the same horizontal section orientation and / or a distance less than a preset threshold within an area of ​​a predetermined size centered on the target horizontal well;

[0013] Combining the well-connected geological profile with the coal seam sedimentary environment data and reservoir configuration characteristics in the work area to obtain the locations of the dual control lines and the multiple coal seams;

[0014] The well-connected geological profile is combined with the well location data and well deviation data of the adjacent wells to establish the small layer plane regularity map.

[0015] Optionally, the step of combining the well-connected geological profile with the coal seam sedimentary environment data and reservoir configuration characteristics in the work area to obtain the positions of the dual control lines and the multiple coal seams includes:

[0016] Obtaining the position of the second control line based on the results of the four-property analysis of the target coal seam, the roof and the floor, wherein the four-property analysis includes lithology analysis, physical property analysis, gas content analysis and electrical property analysis;

[0017] The position of the first control line is obtained based on the lithology analysis results and electrical analysis results of the target coal seam.

[0018] Optionally, the three-dimensional geological model of the target horizontal well is established, combined with the plane regularity map of the small layer, the position of the dual control line in the three-dimensional geological model of the target horizontal well is obtained, and one of the multiple coal small layers is used as the target drilling reservoir, including:

[0019] The well-connected geological profile and the small-layer plane regularity map are used as basic data to construct a regional three-dimensional geological model to obtain the target horizontal well three-dimensional geological model, which includes, from shallow to deep, the roof, the target coal seam, and the floor;

[0020] The three-dimensional geological model of the target horizontal well is combined with actual production data to determine one of the multiple coal seams as the target drilling reservoir, wherein the actual production data includes the production data of the target coal seam in each coalbed methane production well in the work area.

[0021] Optionally, the end point of the landing phase drilling trajectory is the landing target point, and the starting point and end point of the horizontal section drilling trajectory are the landing target point and the completion drilling target point, respectively.

[0022] Optionally, in the first process in which the drill bit drills according to the landing stage drilling trajectory, updating the position of the dual control line in the three-dimensional geological model of the target horizontal well according to the acquired first actual drilling data, and correcting the landing stage drilling trajectory according to the first actual drilling data and the updated position of the dual control line, includes:

[0023] In the first process, first real drilling data is obtained, wherein the first real drilling data includes first logging while drilling data, first logging while drilling cuttings sample and real-time altitude depth of the drill bit, and the three-dimensional geological model of the target horizontal well is updated according to the first real drilling data to obtain a first updated three-dimensional geological model of the target horizontal well and a first updated dual control line, wherein the first logging while drilling data includes gamma logging while drilling;

[0024] Predicting the difference in altitude depth between the drill bit and the top surface of the target drilling reservoir by combining the first updated target horizontal well three-dimensional geological model, the first updated dual control line and the real-time altitude depth of the drill bit;

[0025] The landing phase drilling trajectory is corrected according to a first predetermined principle, including correcting the landing target point position, wherein the first predetermined principle includes: the corrected landing target point is located on the top surface of the target drilling reservoir, and the drilling distance of the drill bit to the corrected landing target point is the shortest.

[0026] Optionally, before correcting the drilling trajectory in the landing phase according to the first predetermined principle, the method further includes:

[0027] The first predetermined principle is obtained by combining the first updated dual control line and the predicted difference in depth above sea level between the drill bit and the top surface of the target drilling reservoir.

[0028] Optionally, in the second process in which the drill bit drills according to the horizontal section drilling trajectory, the position of the dual control line in the three-dimensional geological model of the target horizontal well is updated again according to the acquired second real drilling data, and it is judged whether the drill bit is ejected or bottomed out according to the second real drilling data and the position of the dual control line after being updated again, and if so, the horizontal section drilling trajectory is corrected, including:

[0029] In the second process, second real drilling data is obtained, wherein the second real drilling data includes second logging while drilling data, second logging while drilling cuttings samples, and the real-time altitude depth of the drill bit, and the first updated three-dimensional geological model of the target horizontal well is updated according to the second real drilling data to obtain a second updated three-dimensional geological model of the target horizontal well and a second updated dual control line, wherein the second logging while drilling data includes gamma logging while drilling;

[0030] According to the second updated double control line and the real-time altitude depth of the drill bit, determine whether the drill bit is ejected or bottomed out. If so, correct the horizontal section drilling trajectory according to the second predetermined principle, including correcting the completion target point position. The second predetermined principle includes: the corrected horizontal section drilling trajectory is located within the target drilling reservoir.

[0031] On the other hand, an embodiment of the present application also provides a geological guidance device for multi-layered coalbed methane horizontal wells, including a processor and a memory, wherein the memory is used to store a program for geological guidance of multi-layered coalbed methane horizontal wells, and the processor is used to read the program for geological guidance of multi-layered coalbed methane horizontal wells and perform a geological guidance method for multi-layered coalbed methane horizontal wells.

[0032] On the other hand, an embodiment of the present application further provides a non-transient computer storage medium storing a computer program, which, when executed by a processor, can implement a method for geosteering of multi-layered coalbed methane horizontal wells.

[0033] Compared with the related technologies, the geo-steering method and device for multi-layered overlapping coalbed methane horizontal wells of the embodiments of the present application are suitable for multi-layered overlapping coal reservoirs, can guide the drilling trajectory of coalbed methane horizontal wells in real time, control the relative position of the drill bit, ensure smooth drilling of the drill bit, reduce the drilling of non-reservoir sections and large fluctuations in the wellbore trajectory, and improve the drilling rate of the target coalbed methane reservoir.

[0034] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0036] Figure 1 This is a flow chart of the geosteering method for multi-layer stacked coalbed methane horizontal wells according to an embodiment of the present application;

[0037] Figure 2 Schematic diagram of a geosteering device for multi-layer stacked coalbed methane horizontal wells according to an embodiment of the present application;

[0038] Figure 3 It is a schematic diagram of a Taiyuan Formation coal seam and its roof and floor in a neighboring well in the working area of ​​an embodiment of the present application;

[0039] Figure 4 It is a schematic diagram of the three-dimensional geological model and drilling trajectory of the target horizontal well in the embodiment of the present application. DETAILED DESCRIPTION

[0040] The present application describes multiple embodiments, but the description is exemplary rather than restrictive, and it is obvious to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described in the present application. Although many possible feature combinations are shown in the drawings and discussed in the specific embodiments, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0041] The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features and elements disclosed in the present application may also be combined with any conventional features or elements to form a unique invention scheme defined by the claims. Any features or elements of any embodiment may also be combined with features or elements from other invention schemes to form another unique invention scheme defined by the claims. Therefore, it should be understood that any feature shown and / or discussed in the present application may be implemented individually or in any appropriate combination. Therefore, except for the limitations made according to the attached claims and their equivalents, the embodiments are not subject to other restrictions. In addition, various modifications and changes may be made within the scope of protection of the attached claims.

[0042] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not rely on the specific order of the steps described herein, the method or process should not be limited to the steps of the specific order described. As will be understood by those of ordinary skill in the art, other sequences of steps are also possible. Therefore, the specific sequence of the steps set forth in the specification should not be interpreted as a limitation to the claims. In addition, the claims for the method and / or process should not be limited to the steps of performing them in the order written, and those skilled in the art can easily understand that these sequences can be changed and still remain within the spirit and scope of the embodiments of the present application.

[0043] In the coalbed methane mining practice in a certain work area, through detailed comparative analysis of the reservoir configuration in the work area, it was found that two sets of relatively stable and continuous thin carbonaceous mudstones, also called gangue layers, were developed inside the Taiyuan Formation coal seam. The target coal seam was subdivided into three sections. The lithology and electrical characteristics of the gangue layers were significantly different from those of the coal seams. Therefore, these two sets of gangue layers can be used as key marker layers inside the target coal seam, that is, the first control line. In addition, the roof of the target coal seam usually develops dark mudstone, and the bottom of the target coal seam is gray-black fine sandstone. The lithology and electrical characteristics of the roof and bottom are significantly different from those of the coal seam. Therefore, the roof and bottom of the target coal seam can be used as secondary marker layers, that is, the second control line. Consider introducing the double control line consisting of the first control line and the second control line into the geosteering technology of multi-layer superimposed coalbed methane horizontal wells.

[0044] The present application embodiment provides a method for geosteering a multi-layer stacked coalbed methane horizontal well. Figure 1 As shown, steps S100-S500 are included:

[0045] S100: Based on the data of adjacent wells, a small layer plane regularity map of the target coal seam and its roof and floor is established; the small layer includes a double control line and multiple small coal seams, wherein the double control line includes a first control line and a second control line, the first control line is a coal gangue layer located inside the target coal seam, and the target coal seam is divided into the multiple coal small layers; the second control line is the roof and the floor of the target coal seam;

[0046] S200: Establish a three-dimensional geological model of the target horizontal well, combine it with the plane regularity map of the small layer, obtain the position of the dual control line in the three-dimensional geological model of the target horizontal well, and use one of the multiple coal small layers as the target drilling reservoir;

[0047] S300: acquiring a designed drilling trajectory of a target horizontal well according to the target drilling reservoir, including a landing stage drilling trajectory and a horizontal section drilling trajectory;

[0048] S400: in a first process in which the drill bit performs drilling according to the landing stage drilling trajectory, updating the position of the dual control line in the three-dimensional geological model of the target horizontal well according to the acquired first actual drilling data, and correcting the landing stage drilling trajectory according to the first actual drilling data and the updated position of the dual control line;

[0049] S500: In the second process of the drill bit drilling according to the horizontal section drilling trajectory, the position of the double control line in the three-dimensional geological model of the target horizontal well is updated again according to the second actual drilling data obtained, and according to the second actual drilling data and the position of the double control line after the update again, it is judged whether the drill bit is ejected or bottomed out. If so, the horizontal section drilling trajectory is corrected.

[0050] In this embodiment, the adjacent wells include directional wells or vertical wells in the work area, and stratigraphic comparison can be performed based on the data of the adjacent wells to delineate the target coal seam.

[0051] In this embodiment, by correcting the drilling trajectory in the landing phase, the drill bit can be smoothly landed on the top surface of the target drilling reservoir.

[0052] In this embodiment, the target drilling reservoir is located within the target reservoir, and by correcting the horizontal section drilling trajectory, the drill bit can be kept drilling within the target drilling reservoir.

[0053] The multi-layer overlapping coalbed methane horizontal well geosteering method in this embodiment can guide the horizontal well drilling trajectory in real time, detect abnormal situations of drill bit top-out or drill bit bottom-out through double control lines, and timely guide the drill bit to adjust its azimuth, control the relative position of the drill bit, and ensure smooth drilling of the drill bit.

[0054] In an exemplary embodiment, step S100 further includes S101-S103:

[0055] S101: Perform stratigraphic comparison based on well logging data and mud logging data of adjacent wells and establish a geological profile of connected wells;

[0056] S102: combining the well-connected geological profile with the coal seam sedimentary environment data and reservoir configuration characteristics in the work area to obtain the positions of the dual control line and the multiple coal seams;

[0057] S103: Combining the well-connected geological profile with the well location data and well deviation data of the adjacent wells to establish the small layer plane regularity map.

[0058] In this embodiment, the number of the adjacent wells is multiple, including drilled wells within an area of ​​a predetermined size centered on the target horizontal well, with the horizontal sections having the same orientation and / or a distance less than a preset threshold.

[0059] In this embodiment, the position of the second control line is obtained based on the results of four-property analysis of the target coal seam, the roof and the floor, and the four-property analysis includes lithology analysis, physical property analysis, gas content analysis and electrical property analysis.

[0060] In this embodiment, the position of the first control line is obtained based on the lithology analysis results and electrical analysis results of the target coal seam.

[0061] In this embodiment, when establishing a well-connected geological profile, it is necessary to analyze the sedimentary environment and configuration cycle of the target coal seam, and to divide the sub-layers inside the target coal seam in detail in combination with the lithological analysis and electrical analysis characteristics of the target coal seam, for example, to perform lithological analysis based on the natural gamma curve.

[0062] In this embodiment, the small layer plane regularity map includes the small layer plane regularity map of the double-layer control line, and also includes the small layer plane regularity map of multiple coal small layers, and each small layer corresponds to a small layer plane regularity map.

[0063] In an exemplary embodiment, step S200 further includes S201-S202:

[0064] S201: constructing a regional three-dimensional geological model by using the well-connected geological profile map and the small-layer plane regularity map as basic data to obtain the three-dimensional geological model of the target horizontal well;

[0065] S202: Combining the three-dimensional geological model of the target horizontal well with actual production data, and determining one of the multiple coal seams as the target drilling reservoir.

[0066] In this embodiment, the three-dimensional geological model of the target horizontal well includes, from shallow to deep, the roof, the target coal seam, and the floor, wherein the target coal seam includes a gangue layer and multiple coal sub-layers; the gangue layer is the first control line, and the roof and the floor are the second control line.

[0067] In this embodiment, the actual production data includes the production data of the target coal seam in each coalbed methane production well in the work area, and the coal seam with high production in the production well is taken as the target drilling reservoir.

[0068] In this embodiment, when establishing a regional three-dimensional geological model, the well-connected geological profile map and the small layer plane regularity map are used as basic data. The more wells there are, the more accurate the regional three-dimensional geological model obtained will be. The sedimentary environment of the coal seams in the work area, reservoir configuration data, three-dimensional seismic exploration data, geochemical data and regional geological structure data are combined to achieve accurate regional three-dimensional geological modeling.

[0069] In this embodiment, the three-dimensional geological model of the target horizontal well includes the structural change trend of the target horizontal well, the altitude depth of the top and bottom interfaces of each sublayer, and the lithology change characteristics, including the dual control line and the altitude depth and lithology change of each coal sublayer.

[0070] In an exemplary embodiment, the end point of the landing phase drilling trajectory in step S300 is the landing target point, and the starting point and the end point of the horizontal section drilling trajectory are the landing target point and the completion drilling target point, respectively.

[0071] In an exemplary embodiment, step S400 further includes S401-S403:

[0072] S401: in the first process, first actual drilling data is obtained, wherein the first actual drilling data includes first logging while drilling data, first logging while drilling cuttings sample and real-time altitude depth of the drill bit, and the three-dimensional geological model of the target horizontal well is updated according to the first actual drilling data to obtain a first updated three-dimensional geological model of the target horizontal well and a first updated dual control line, wherein the first logging while drilling data includes gamma logging while drilling;

[0073] S402: predicting the difference in altitude depth between the drill bit and the top surface of the target drilling reservoir by combining the first updated target horizontal well three-dimensional geological model, the first updated dual control line and the real-time altitude depth of the drill bit;

[0074] S403: Correcting the landing stage drilling trajectory according to a first predetermined principle, including correcting the landing target point position, wherein the first predetermined principle includes: the corrected landing target point is located on the top surface of the target drilling reservoir, and the drilling distance of the drill bit to the corrected landing target point is the shortest.

[0075] In this embodiment, before correcting the landing phase drilling trajectory according to the first predetermined principle, it also includes: combining the first updated double control line and the predicted difference in altitude depth between the drill bit and the top surface of the target drilling reservoir to obtain the first predetermined principle.

[0076] In this embodiment, before the drill bit lands, the first actual drilling data is tracked in real time and compared with the three-dimensional geological model of the target horizontal well. If the three-dimensional geological model of the target horizontal well does not match the first actual drilling data, the three-dimensional geological model of the target horizontal well is updated in time, and the position of the dual control line in the three-dimensional geological model of the target horizontal well is updated, which serves as the basis for subsequent drilling.

[0077] In an exemplary embodiment, step S500 further includes S501-S502:

[0078] S501: in the second process, obtaining second actual drilling data, the second actual drilling data including second logging while drilling data, second logging while drilling cuttings samples and the real-time altitude depth of the drill bit, updating the first updated target horizontal well three-dimensional geological model according to the second actual drilling data, obtaining a second updated target horizontal well three-dimensional geological model and a second updated dual control line, wherein the second logging while drilling data includes gamma logging while drilling;

[0079] S502: Determine whether the drill bit is ejected or bottomed out based on the second updated double control line and the real-time altitude depth of the drill bit. If so, correct the horizontal section drilling trajectory according to a second predetermined principle, including correcting the completion target point position. The second predetermined principle includes: the corrected horizontal section drilling trajectory is located within the target drilling reservoir.

[0080] In this embodiment, updating the first updated target horizontal well three-dimensional geological model according to the second actual drilling data in step S501 includes correcting the thickness of the target drilling reservoir and the altitude depth of the top and bottom interfaces of the target drilling reservoir.

[0081] In this embodiment, the second actual drilling data is tracked in real time and compared with the first updated target horizontal well three-dimensional geological model. If the first updated target horizontal well three-dimensional geological model is inconsistent with the second actual drilling data, the first updated target horizontal well three-dimensional geological model is updated in time, and the position of the dual control line is updated, which serves as the basis for subsequent drilling.

[0082] The present application also provides a multi-layer stacked coalbed methane horizontal well geosteering device, such as Figure 2As shown, it includes a processor and a memory, wherein the memory is used to store a program for geo-steering of multi-layered coalbed methane horizontal wells, and the processor is used to read the program for geo-steering of multi-layered coalbed methane horizontal wells and perform a geo-steering method for multi-layered coalbed methane horizontal wells.

[0083] The embodiment of the present application also provides a non-transient computer storage medium storing a computer program, which, when executed by a processor, can implement a method for geosteering multi-layered coalbed methane horizontal wells.

[0084] The above embodiment is specifically described below using an example.

[0085] In the coalbed methane mining practice in a certain work area, through the detailed comparative analysis of the reservoir configuration in the work area, the Taiyuan Formation underwent short-term changes in the base level cycle during the sedimentary period. Taking the Taiyuan Formation coal seam in a neighboring well as an example, Figure 3 As shown in the figure, two sets of relatively stable and continuous thin layers of carbonaceous mudstone are developed inside the target coal seam, namely the first gangue layer and the second gangue layer. The target coal seam is subdivided into three sections, namely the first coal seam, the second coal seam and the third coal seam. The lithology and electrical characteristics of the gangue layer are significantly different from those of the coal seam. Therefore, the first gangue layer and the second gangue layer can be used as the key marker layers inside the target coal seam, that is, the first control line. In addition, the roof of the target coal seam usually develops dark mudstone, and the bottom of the target coal seam is gray-black fine sandstone. The lithology and electrical characteristics of the roof and bottom are significantly different from those of the coal seam. Therefore, the roof and bottom of the target coal seam can be used as secondary marker layers, that is, the second control line. Consider introducing a double control line consisting of the first control line and the second control line into the geosteering technology of multi-layered coalbed methane horizontal wells to guide the horizontal well drilling trajectory in real time, control the relative position of the drill bit, ensure smooth drilling of the drill bit, reduce the drilling of non-reservoir sections and large fluctuations in the wellbore trajectory, and improve the drilling rate of coalbed methane reservoirs.

[0086] The geosteering method for multi-layer stacked coalbed methane horizontal wells includes the following steps:

[0087] Step 1: Perform stratigraphic comparison based on well logging data and mud logging data of adjacent wells to establish a connected well geological profile, wherein the number of adjacent wells is multiple, and the adjacent wells include wells drilled within an area of ​​a predetermined size centered on the target horizontal well, with the horizontal sections having the same orientation and / or a distance less than a preset threshold, and determine the target coal seam as the Taiyuan Formation coal seam based on the connected well geological profile;

[0088] The well-connected geological profile is combined with the coal seam sedimentary environment data and reservoir configuration characteristics in the work area, and the position of the second control line is obtained based on the four-property analysis results of the target coal seam, the roof and the floor. The four-property analysis includes lithology analysis, physical property analysis, gas content analysis and electrical property analysis. The second control line is the roof and the floor of the target coal seam. The roof of the Taiyuan Formation coal seam in the work area generally develops thick mudstone with a natural gamma value of 130-180, and the floor of the Taiyuan Formation coal seam generally develops gray-black fine sandstone with a natural gamma value of 80-100. The natural gamma value of the Taiyuan Formation coal seam is 40-70. It can be seen that the target coal seam is significantly different from its roof and floor, and the roof and floor are used as the second control line;

[0089] The well-connected geological profile is combined with the coal seam sedimentary environment data and reservoir configuration characteristics in the work area, and the position of the first control line is obtained based on the lithology analysis results and electrical analysis results of the target coal seam. The first control line is the gangue layer located inside the target coal seam. The target coal seam is divided into the multiple coal sub-layers. The Taiyuan Group coal seam is analyzed in detail and divided into five sub-layers according to the sub-layer comparison results, from shallow to deep: the first coal sub-layer, the first gangue layer, the second coal sub-layer, the second gangue layer, and the third coal sub-layer. The first gangue layer and the second gangue layer are dark carbonaceous mudstones with a natural gamma value of 150-200, and the natural gamma values ​​of the first coal sub-layer, the second coal sub-layer and the third coal sub-layer are 40-70. It can be seen that there are obvious differences between the gangue layer and the coal sub-layer, and the first gangue layer and the second gangue layer are taken as the first control line;

[0090] The connected well geological profile is combined with the well location data and well inclination data of the adjacent wells to establish the sub-layer plane regularity map, which includes the roof plane regularity map, the first coal sub-layer plane regularity map, the first coal gangue layer plane regularity map, the second coal sub-layer plane regularity map, the second coal gangue layer plane regularity map, the third coal sub-layer plane regularity map and the bottom plate plane regularity map.

[0091] Step 2: Use the well-connected geological profile and the small-layer plane regularity map as basic data to construct a regional three-dimensional geological model to obtain the target horizontal well three-dimensional geological model. When establishing the regional three-dimensional geological model, use the well-connected geological profile and the small-layer plane regularity map as basic data. The more wells there are, the more accurate the regional three-dimensional geological model will be. Combined with the sedimentary environment, reservoir configuration data, three-dimensional seismic exploration data, geochemical data and regional geological structure data of the coal seams in the work area, accurate regional three-dimensional geological modeling can be achieved; Figure 4 As shown, the three-dimensional geological model of the target horizontal well includes, from shallow to deep, the roof, the first coal layer, the first coal gangue layer, the second coal layer, the second coal gangue layer, the third coal layer, and the floor. Figure 4The mudstone in the middle roof is represented by thin horizontal lines, the first coal layer, the second coal layer and the third coal layer are represented by vertical lines, the carbonaceous mudstone in the first coal gangue layer and the second coal gangue layer are represented by thick horizontal lines, and the fine sandstone in the bottom plate is represented by dots;

[0092] The three-dimensional geological model of the target horizontal well is combined with the actual production data to determine one of the multiple coal seams as the target drilling reservoir, wherein the actual production data includes the production data of the target coal seam of each coalbed methane production well in the work area. Specifically, the second coal seam is determined as the target drilling reservoir with a thickness of 4-5 meters.

[0093] Step 3: Obtain the designed drilling trajectory of the target horizontal well according to the target drilling reservoir, including the landing stage drilling trajectory and the horizontal section drilling trajectory, such as Figure 4 As shown in the dotted line segment, the end point of the landing stage drilling trajectory is the landing target point A, and the starting point and end point of the horizontal section drilling trajectory are the landing target point A and the completion drilling target point B, respectively.

[0094] Step 4: in the first process of the drill bit drilling according to the landing stage drilling trajectory, the position of the dual control line in the three-dimensional geological model of the target horizontal well is updated according to the first actual drilling data obtained, and the landing stage drilling trajectory is corrected according to the first actual drilling data and the updated position of the dual control line;

[0095] In the process of the drill bit drilling according to the landing stage drilling trajectory, first real drilling data is obtained, wherein the first real drilling data includes first logging while drilling data, first logging while drilling cuttings sample and real-time altitude depth of the drill bit, and the three-dimensional geological model of the target horizontal well is updated according to the first real drilling data to obtain a first updated three-dimensional geological model of the target horizontal well and a first updated dual control line, wherein the first logging while drilling data includes gamma logging while drilling;

[0096] Predicting the difference in altitude depth between the drill bit and the top surface of the target drilling reservoir by combining the first updated target horizontal well three-dimensional geological model, the first updated dual control line and the real-time altitude depth of the drill bit;

[0097] The first predetermined principle is obtained by combining the first updated dual control line and the predicted difference in depth above sea level between the drill bit and the top surface of the target drilling reservoir;

[0098] According to the first predetermined principle, the drilling trajectory of the landing phase is corrected, including correcting the position of the landing target point from A to A. 1 , A 1 Located at the top of the second coal seam, the corrected landing stage drilling trajectory is Figure 4 The solid line segment representing the actual drilling trajectory from 750m above sea level to A1 The first predetermined principle includes: the corrected landing target point is located on the top surface of the second coal seam top, and the drilling distance of the drill bit to the corrected landing target point is the shortest.

[0099] Step 5: obtaining second real drilling data during the second process of the drill bit drilling according to the horizontal section drilling trajectory, the second real drilling data including second logging while drilling data, second logging while drilling cuttings samples and the real-time altitude depth of the drill bit, updating the first updated target horizontal well three-dimensional geological model according to the second real drilling data, obtaining a second updated target horizontal well three-dimensional geological model and a second updated dual control line, wherein the second logging while drilling data includes gamma logging while drilling;

[0100] According to the second updated double control line and the real-time altitude depth of the drill bit, it is determined whether the drill bit is ejected or bottomed out. If so, the horizontal section drilling trajectory is corrected according to the second predetermined principle, including correcting the position of the drilling target point, and correcting the drilling target point from B to B. 1 The drilling target is located at B 1 Located in the second coal seam, the revised horizontal drilling trajectory is Figure 4 The solid line segment representing the actual drilling trajectory starts from A 1 Point to B 1 The trajectory segment of the point, the second predetermined principle includes: the corrected horizontal segment drilling trajectory is located in the second coal seam.

[0101] In step five, the second coal seam is taken as the target drilling reservoir, and its first control line is the first coal gangue layer and the second coal gangue layer, and the second control line is the roof and the bottom plate. Under normal circumstances, the first control line can ensure that the drill bit always drills in the second coal seam. If the drill bit enters the first coal gangue layer, or the drill bit enters the second coal gangue layer, the drilling gamma logging data in the second drilling logging data will show a significant increasing trend, and the second drilling logging cuttings sample will also change from coal rock to carbonaceous limestone. At this time, the drilling direction of the drill bit should be adjusted in time to ensure that the drill bit drills in the second coal seam.

[0102] In step five, that is, during the horizontal drilling process, under special circumstances, the drill bit will be adjusted to drill in the first coal gangue layer or the second coal gangue layer, that is, to drill in the first control line, with the purpose of obtaining the actual drilling data in the first coal gangue layer and the second coal gangue layer, so as to obtain the accurate lithological characteristics and electrical characteristics of the first control line in the target horizontal well, so as to better guide the subsequent drilling process. After the drill bit has drilled in the coal gangue layer for a period of time, it will receive a control signal to return to the second coal sub-layer for drilling, adjust the drilling direction of the drill bit, and make the drill bit return to the second coal sub-layer for drilling; in very rare cases, the drill bit will enter the second control line, that is, the drill bit enters the roof or floor. At this time, according to the second actual drilling data, it can be found in time that the drill bit has seriously deviated from the second coal sub-layer. At this time, it is necessary to adjust the drilling direction of the drill bit in time to make the drill bit return to the second coal sub-layer to ensure the drilling rate of the target drilling reservoir.

[0103] In addition to the approach of this exemplary embodiment, a multi-layered coalbed methane horizontal well geosteering method can be obtained by combining one set of coal gangue layers with the roof and floor of the target coal seam, or more than two sets of coal gangue layers with the roof and floor of the target coal seam.

[0104] It will be appreciated by those skilled in the art that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those of ordinary skill in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

Claims

1. A geosteering method for multi-layered coalbed methane horizontal wells, characterized in that: include: Based on the data from adjacent wells, a plane regularity map of the small layers of the target coal seam and its roof and floor is established; the small layers include a double control line and multiple small coal seams, wherein the double control line includes a first control line and a second control line, the first control line is the coal gangue layer located inside the target coal seam, and the target coal seam is divided into the multiple coal small layers; the second control line is the roof and the floor of the target coal seam; Establishing a three-dimensional geological model of the target horizontal well, combining it with the plane regularity map of the small layer, obtaining the position of the dual control line in the three-dimensional geological model of the target horizontal well, and drilling into the reservoir with one of the multiple coal small layers as the target; Acquiring a designed drilling trajectory of a target horizontal well according to the target drilling reservoir, including a landing stage drilling trajectory and a horizontal section drilling trajectory; In a first process in which the drill bit drills according to the landing stage drilling trajectory, the position of the dual control line in the three-dimensional geological model of the target horizontal well is updated according to the first actual drilling data obtained, and the landing stage drilling trajectory is corrected according to the first actual drilling data and the updated position of the dual control line; In the second process of the drill bit drilling according to the horizontal section drilling trajectory, the position of the double control line in the three-dimensional geological model of the target horizontal well is updated again according to the second actual drilling data obtained, and it is judged whether the drill bit is ejected or bottomed out according to the second actual drilling data and the position of the double control line after the update. If so, the horizontal section drilling trajectory is corrected.

2. The geosteering method for multi-layered coalbed methane horizontal wells according to claim 1, characterized in that: The target coal seam and its roof and floor small layer plane regularity map are established based on the data of adjacent wells, including: Performing stratigraphic comparison based on well logging data and mud logging data of adjacent wells to establish a well-connected geological profile, wherein the number of adjacent wells is multiple, and the adjacent wells include drilled wells with the same horizontal section orientation and / or a distance less than a preset threshold within an area of ​​a predetermined size centered on the target horizontal well; Combining the well-connected geological profile with the coal seam sedimentary environment data and reservoir configuration characteristics in the work area to obtain the locations of the dual control lines and the multiple coal seams; The well-connected geological profile is combined with the well location data and well deviation data of the adjacent wells to establish the small layer plane regularity map.

3. The geosteering method for multi-layered coalbed methane horizontal wells according to claim 2, characterized in that: The method of combining the well-connected geological profile with the coal seam sedimentary environment data and reservoir configuration characteristics in the work area to obtain the positions of the dual control line and the multiple coal seams includes: Obtaining the position of the second control line based on the results of the four-property analysis of the target coal seam, the roof and the floor, wherein the four-property analysis includes lithology analysis, physical property analysis, gas content analysis and electrical property analysis; The position of the first control line is obtained based on the lithology analysis results and electrical analysis results of the target coal seam.

4. The geosteering method for multi-layered coalbed methane horizontal wells according to claim 2, characterized in that: The method of establishing a three-dimensional geological model of a target horizontal well, combining it with the plane regularity map of the small layer, obtaining the position of the dual control line in the three-dimensional geological model of the target horizontal well, and drilling into a reservoir with one of the multiple coal small layers as a target includes: The well-connected geological profile and the small-layer plane regularity map are used as basic data to construct a regional three-dimensional geological model to obtain the target horizontal well three-dimensional geological model, which includes, from shallow to deep, the roof, the target coal seam, and the floor; The three-dimensional geological model of the target horizontal well is combined with actual production data to determine one of the multiple coal seams as the target drilling reservoir, wherein the actual production data includes the production data of the target coal seam in each coalbed methane production well in the work area.

5. The geosteering method for multi-layered coalbed methane horizontal wells according to claim 1, characterized in that: The end point of the landing stage drilling trajectory is the landing target point, and the starting point and end point of the horizontal section drilling trajectory are the landing target point and the completion drilling target point, respectively.

6. The geosteering method for multi-layered coalbed methane horizontal wells according to claim 5, characterized in that: In the first process of the drill bit drilling according to the landing stage drilling trajectory, updating the position of the dual control line in the three-dimensional geological model of the target horizontal well according to the acquired first actual drilling data, and correcting the landing stage drilling trajectory according to the first actual drilling data and the updated position of the dual control line, including: In the first process, first real drilling data is obtained, wherein the first real drilling data includes first logging while drilling data, first logging while drilling cuttings sample and real-time altitude depth of the drill bit, and the three-dimensional geological model of the target horizontal well is updated according to the first real drilling data to obtain a first updated three-dimensional geological model of the target horizontal well and a first updated dual control line, wherein the first logging while drilling data includes gamma logging while drilling; Predicting the difference in altitude depth between the drill bit and the top surface of the target drilling reservoir by combining the first updated target horizontal well three-dimensional geological model, the first updated dual control line and the real-time altitude depth of the drill bit; The landing phase drilling trajectory is corrected according to a first predetermined principle, including correcting the landing target point position, wherein the first predetermined principle includes: the corrected landing target point is located on the top surface of the target drilling reservoir, and the drilling distance of the drill bit to the corrected landing target point is the shortest.

7. The geosteering method for multi-layered coalbed methane horizontal wells according to claim 6, characterized in that: Before correcting the drilling trajectory in the landing phase according to the first predetermined principle, the method further includes: The first predetermined principle is obtained by combining the first updated dual control line and the predicted difference in depth above sea level between the drill bit and the top surface of the target drilling reservoir.

8. The geosteering method for multi-layered coalbed methane horizontal wells according to claim 6, characterized in that: In the second process in which the drill bit drills according to the horizontal section drilling trajectory, the position of the dual control line in the three-dimensional geological model of the target horizontal well is updated again according to the acquired second actual drilling data, and whether the drill bit is pushed out or bottomed out is judged according to the second actual drilling data and the position of the dual control line after being updated again, and if so, the horizontal section drilling trajectory is corrected, including: In the second process, second real drilling data is obtained, wherein the second real drilling data includes second logging while drilling data, second logging while drilling cuttings samples, and the real-time altitude depth of the drill bit, and the first updated three-dimensional geological model of the target horizontal well is updated according to the second real drilling data to obtain a second updated three-dimensional geological model of the target horizontal well and a second updated dual control line, wherein the second logging while drilling data includes gamma logging while drilling; According to the second updated double control line and the real-time altitude depth of the drill bit, determine whether the drill bit is ejected or bottomed out. If so, correct the horizontal section drilling trajectory according to the second predetermined principle, including correcting the completion target point position. The second predetermined principle includes: the corrected horizontal section drilling trajectory is located within the target drilling reservoir.

9. A geosteering device for multi-layered coalbed methane horizontal wells, comprising a processor and a memory, characterized in that: The memory is used to store a program for geo-steering of multi-layered coalbed methane horizontal wells, and the processor is used to read the program for geo-steering of multi-layered coalbed methane horizontal wells, and perform the geo-steering method for multi-layered coalbed methane horizontal wells as described in any one of claims 1-8.

10. A non-transitory computer storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the geosteering method for multi-layered coalbed methane horizontal wells as described in any one of claims 1 to 8 can be implemented.

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