A multi-element information fusion based deep shale gas horizontal well geosteering method

Abstract

The present application belongs to the technical field of horizontal well geosteering, and discloses a multi-element information fusion based deep shale gas horizontal well geosteering method, which comprises box optimization, pilot plan modeling, accurate landing and target entering, and horizontal section accurate adjustment. The present application is used for multi-element information fusion based deep shale gas horizontal well geosteering, and rich techniques and methods are accumulated for deep shale gas horizontal well geosteering technology. Through rapid identification of box characteristics, real-time tracking and research, accurate landing and target entering, and fine geosteering tracking, the horizontal section box drilling rate is continuously improved.

Description

Technical Field

[0001] This invention belongs to the field of horizontal well geological steering technology, specifically relating to a geological steering method for deep shale gas horizontal wells based on multi-source information fusion. Background Technology

[0002] To achieve large-scale and efficient development of deep shale gas in southern Sichuan and improve the test production and EUR level of horizontal wells, it is necessary to drill as many "platinum targets" (with optimal geological parameters, high silica content, and optimal compressibility) as possible, given their "double sweet spot" in geological and engineering conditions. Horizontal well development in shale gas shows that the location and drilling length of the target in the horizontal section are important factors affecting the productivity of horizontal wells, and improving the target drilling rate is key to achieving efficient development. Research indicates that Longyi 1... 1+2 The gas production contribution of the sublayer is Longyi 1 3+4 The success rate of platinum target drilling in horizontal wells is twice that of the No. 1 layer; the longer the horizontal section encountered by the platinum target, the higher the test production and the EUR per well; a smooth trajectory is beneficial for shortening the drilling cycle, casing installation, fracturing to prevent casing deformation, etc. Therefore, improving the platinum target drilling rate in horizontal wells while ensuring a smooth trajectory is the foundation for the efficient production of shale gas in the configuration area.

[0003] Patent application CN116025280A discloses a horizontal well geodetic guidance method. This method calculates the dip angle θ based on two adjacent cross-section points on the horizontal well trajectory, where θ = arctan(ΔH / ΔL), ΔH is the vertical depth difference between the two adjacent cross-section points, and ΔL is the horizontal projection distance between the two adjacent cross-section points. The method compares the dip angle θ with the apparent dip angle range αmin-αmax of the formation in the target section of the horizontal well. The drilling angle is then adjusted. When αmin ≤ θ ≤ αmax, if the previous cross-section point is located at the top of the reservoir, the drilling is deflected downwards; if the previous cross-section point is located at the bottom of the reservoir, the drilling is inclined upwards. When θ < αmin or θ > αmax, if the previous cross-section point is located at the top of the reservoir, the drilling is inclined upwards; if the previous cross-section point is located at the bottom of the reservoir, the drilling is deflected downwards. This method solves the problem that during horizontal well drilling, the position of the drill bit cannot be determined using data such as drilling GR and elemental logging in formations with similar top and bottom conditions. However, this patent does not provide a specific solution for horizontal wells with large variations in the thickness of each segment of the target layer, simple lithology, few GR marker layers, strong multiple interpretations of curves, large structural errors, thin target body, differences in target body position between wells, low accuracy in identifying micro faults and predicting formation dip angles, nor does it achieve rapid identification of box features and real-time tracking and analysis. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a geological steering method for deep shale gas horizontal wells based on multi-source information fusion. This method, based on multi-source information fusion for deep shale gas horizontal well steering, has accumulated rich technical and methodological expertise in deep shale gas horizontal well steering technology. By rapidly identifying box characteristics, real-time tracking and analysis, precise landing and target entry, and fine steering tracking, it continuously improves the drilling rate of horizontal box sections.

[0005] The above-mentioned objective of this invention is achieved through the following technical solution: a geological steering method for deep shale gas horizontal wells based on multi-source information fusion, comprising the following steps:

[0006] 1. Box selection: Select horizontal target layers, determine reservoir thickness, combine elemental characteristics to determine box thickness, and determine roadway location;

[0007] 2. Guiding plan modeling: Developing a horizontal well guiding construction plan;

[0008] 3. Precise landing and target entry: Determine the vertical depth and inclination of the landing segment, develop an effective control method for the landing segment's target entry, and clarify the reasons for the changes in the thickness of the sublayer in the landing segment;

[0009] 4. Precise adjustment of horizontal sections: closely track the actual drilling trajectory on site, carefully analyze the position of the trajectory within the box, calculate the dip angle of the strata, determine the trajectory relationship, clarify the box information, and comprehensively use the above information to precisely adjust the trajectory.

[0010] Furthermore, step 1 specifically involves: selecting platinum target layers for horizontal wells and determining the thickness of Class I reservoirs; based on the thickness of Class I reservoirs and combined with elemental characteristics, determining the box thickness, clarifying the roadway location, and determining the platinum target layers for horizontal wells according to data parameters.

[0011] In a further preferred embodiment of the present invention, in step 1, a gas content greater than 5m³ is selected. 3 A horizontal well platinum target layer is defined as having brittle minerals greater than 65%, porosity greater than 5%, organic carbon greater than 4%, gas saturation greater than 65%, Poisson-Poisson brittleness index greater than 50%, and clay content less than 20%.

[0012] Furthermore, step 2 specifically involves: using drilling data from adjacent wells and combining it with seismic data to develop a directional drilling plan for the horizontal well; the directional drilling plan consists of three parts: target depth prediction, landing trajectory design, and horizontal trajectory design.

[0013] In a further preferred embodiment of the present invention, the guiding construction scheme in step 2 is specifically as follows:

[0014] (1) Target depth prediction: The drilling data is compared with the formation of the regional vertical well. The formation dip angle of the target point is predicted by combining the seismic prediction. The target depth is predicted by correcting the formation thickness and formation dip angle. The target trajectory is then redesigned and optimized.

[0015] (2) Landing trajectory design: The strata of the entire landing section are finely divided by the gamma and element energy spectrum characteristics of the adjacent well (guide well). Six marker layers with obvious and stable gamma and element characteristics are selected. Six control points are set from top to bottom during the landing process, and the layers are approached one by one.

[0016] (3) Horizontal section trajectory design: By slicing the three-dimensional seismic data along the well trajectory direction, the dip angle of the formation is extracted in segments to establish a structural model; then the box parameters of the horizontal well reservoir are predicted, and the reservoir model is established using the reservoir modules of each region integrated by the software; a three-dimensional geological steering model is established before drilling by integrating the reservoir model and the structural model, and the well trajectory is optimized according to the changes in the vertical and horizontal directions of the reservoir; the applicability analysis of micro-fault and curvature location prediction is carried out based on the superposition of different seismic attributes; the data change characteristics of the fault and curvature location encountered during drilling are statistically analyzed, and the fitting technology is used to refine the characterization, establish a fine ant-body geological model, predict micro-fractures in the well area, provide direct reference for the drilling trajectory scheme, and provide early warning of engineering complexity for drilling.

[0017] Furthermore, step 3 specifically involves: determining the vertical depth and dip angle of the landing segment based on the characteristics of different marker layers, forming the "six elements of effective control methods for landing segment target entry"; and clarifying the reasons for the changes in the thickness of the sublayers in the landing segment, including faults of different scales, flexural zones, sedimentary phenomena, and stratigraphic dip factors.

[0018] Furthermore, the "six elements of effective control method" in step 3 are as follows: ① understanding the target entry design requirements, ② analyzing the characteristics of different box-shaped sub-layers, ③ mastering the structural changes of target point A, ④ analyzing the characteristics of marker layer elements, ⑤ calculating the vertical depth of target point A, and ⑥ revising the landing scheme design.

[0019] Furthermore, step 3 clarifies the reasons for the changes in the thickness of the sublayer in the landing section, including faults of different scales, flexural zones, sedimentary phenomena, and stratigraphic dip factors. It clarifies that the changes in sublayer thickness are caused by two main factors:

[0020] (1) When drilling encounters a flexural zone, the dip angle of the strata in the landing section changes from updip to downdip, resulting in a difference between the true thickness and apparent thickness of the strata in the landing section.

[0021] (2) Due to the influence of seismic data, there is a great difference between the seismic axis and the actual drilling trajectory. The landing section often encounters reverse faults of different scales. Through the different orientations of the faults and the well trajectory, the formation may be repeated or missing. Therefore, the faults of different scales affect the thickness or thinning of the sub-layers.

[0022] Furthermore, step 4 specifically involves: closely tracking the actual drilling trajectory in complex horizontal sections where "deflection, faults, and box-shaped hard layers" often occur, accurately judging the box position of the trajectory, calculating the formation dip angle, determining the upper and lower tangent relationships of the trajectory, clarifying the box element logging and drilling GR information, and comprehensively using the above information to accurately adjust the trajectory.

[0023] In a further preferred embodiment of the present invention, the information obtained in step 4 specifically includes: horizontal segment trajectory position determination, horizontal segment stratum dip angle calculation, trajectory vertical tangency analysis, and horizontal segment guidance tracking.

[0024] The beneficial effects of this invention compared to existing technologies are as follows: Utilizing this invention for geological steering of deep shale gas horizontal wells based on multi-source information fusion, it has accumulated rich technical and methodological expertise for deep shale gas horizontal well steering technology. Through rapid identification of box-shaped features, real-time tracking and analysis, precise landing and target entry, and refined steering tracking, it continuously improves the drilling rate of horizontal box-shaped sections. Currently, this technology is applied to 48 horizontal wells on 11 platforms, with an average drilling rate of 94.5%, effectively improving shale gas production capacity. This method is highly feasible, reliable, and widely applicable, providing high-level technical support for geological steering of deep shale gas horizontal wells, and is of great significance for the large-scale and efficient production of deep shale gas. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0026] Figure 1 These are gamma and elemental energy spectrum characteristics of adjacent wells (pilot wells);

[0027] Figure 2 This is a diagram of the trajectory control scheme for the horizontal section of a horizontal well.

[0028] Figure 3 This is a prediction diagram of the formation dip angle of a horizontal well on a platform.

[0029] Figure 4 It is a top-to-bottom gamma-ray analysis map of the stratigraphic incision characteristics;

[0030] Figure 5 This is a schematic diagram illustrating the changes in apparent thickness and true thickness caused by the dip of the strata.

[0031] Figure 6 This is a schematic diagram illustrating the changes in apparent thickness and true thickness caused by the downward dip of the strata.

[0032] Figure 7 This is a schematic diagram showing how the formation thickness is reduced due to the trajectory of well **-1 being in the same direction as the fault dip.

[0033] Figure 8This is a schematic diagram showing how the formation thickness increased due to the trajectory of well ##-4 being opposite to the fault dip direction;

[0034] Figure 9 This is a schematic diagram of the simultaneous design of multiple modeling schemes for the platform's horizontal well;

[0035] Figure 10 This is a tracking chart of the smooth drilling progress in the horizontal section of Well-3.

[0036] Figure 11 This is a geological steering model diagram of well **-6 during drilling;

[0037] Figure 12 This is a tracking diagram of the actual drilling trajectory of Well No. 1.

[0038] Figure 13 This is a geological steering model diagram of well @@-4 during drilling;

[0039] Figure 14 This is a well-drilling geological steering model diagram;

[0040] Figure 15 This is a comparison chart of actual drilling data from wells ##2, ##3, and ##4. Detailed Implementation

[0041] The present invention is described in detail below through specific embodiments, but this does not limit the scope of protection of the present invention. Unless otherwise specified, the experimental methods used in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can all be obtained commercially.

[0042] Example 1

[0043] A geological steering method for deep shale gas horizontal wells based on multi-source information fusion includes the following steps:

[0044] 1) Box selection. Based on the seven-parameter reservoir classification standard, platinum target layers are selected for horizontal wells to determine the thickness of Class I reservoirs; based on the thickness of Class I reservoirs, the box thickness is determined in combination with elemental characteristics, and the location of the roadway is determined.

[0045] 2) Guiding plan modeling. Using gamma and elemental data from adjacent wells (pilot wells), combined with seismic data, a guiding construction plan for horizontal wells is developed. The guiding construction plan consists of three parts: target depth prediction, landing section trajectory design, and horizontal section trajectory design.

[0046] 3) Precise landing and target entry. Based on the characteristics of different marker layers, determine the vertical depth and dip angle of the landing segment, and form the "six elements of effective control methods" for landing segment target entry; at the same time, clarify the reasons for the thickness variation of the four sub-layers in the landing segment, including factors such as faults of different scales, flexural zones, sedimentary phenomena and stratigraphic dip.

[0047] 4) Precise adjustment of horizontal sections. For complex horizontal sections that often encounter "deflection, faults, and hard layers in the box-like formation," the actual drilling trajectory is closely tracked, the box-like formation location of the trajectory is carefully analyzed, the formation dip angle is calculated, the upper and lower tangents of the trajectory are determined, the box-like formation elements are identified from logging and GR information while drilling, and the above information is comprehensively used to precisely adjust the trajectory.

[0048] Step 1: Box Selection. The main development layer for horizontal wells is the WF top-3 sub-layer, 15-20m thick, which is a deep-water shelf rich in organic-rich siliceous mudstone facies, with lithology mainly consisting of siliceous shale. Core and well logging interpretations are combined to evaluate the seven reservoir parameters in the configuration area. Based on reservoir classification standards, horizontal well box selection is carried out to determine the thickness of Class I reservoirs. The variation patterns of Class I reservoir thickness in adjacent wells are compared and analyzed. Combined with structural and fault distribution, the target point design for the horizontal section is optimized. Based on the Class I reservoir thickness and elemental characteristics, the box thickness is determined, and the tunnel location is identified. A seven-parameter standard for the box is formed (Table 1), with a gas content greater than 5m³. 3 / t, brittle minerals greater than 65%, porosity greater than 5%, organic carbon greater than 4%, gas saturation greater than 65%, Poisson-Poisson brittleness index greater than 50%, and clay content less than 20%. The tunnels of the box are mainly distributed in the upper part of the first sub-layer to the middle part of the second sub-layer, and from the top of the second sub-layer to the middle part of the third sub-layer.

[0049] Table 1. Horizontal Well Box Classification and Evaluation Data Table

[0050]

[0051] Step 2: Guiding Plan Modeling. Based on the box thickness and roadway location, and utilizing drilling data such as gamma ray and elemental data from adjacent wells (pilot wells), combined with seismic data, a guiding construction plan for the horizontal well is developed. The guiding construction plan consists of three parts: target depth prediction, landing section trajectory design, and horizontal section trajectory design.

[0052] (1) Target depth prediction. The drilling data is compared with the formation data of the regional vertical wells. Combined with seismic prediction of the formation dip angle at the target point, the target depth is predicted by correcting for formation thickness and dip angle, and the target trajectory is redesigned and optimized. The target vertical depth prediction method includes five aspects: ① prediction based on the top of the adjacent well (guide well), ② target depth prediction based on the current drilling conversion from direct to horizontal drilling, ③ prediction at 5000m of the current drilling conversion from direct to horizontal drilling, ④ vertical depth prediction based on the top of the marker layer, and ⑤ vertical depth prediction based on geological design. The final comprehensive prediction of the target vertical depth is then performed.

[0053] (2) Landing Trajectory Design. The entire landing section was finely divided based on the gamma and elemental energy spectrum characteristics of adjacent wells (pilot wells). Six marker layers with distinct and stable gamma and elemental characteristics were selected. Six control points were established from top to bottom during the landing process, approaching each layer progressively. ① In the top of layer 4, gamma gradually increased, Ca increased, potassium and calcium showed convergence areas, and Fe content decreased; ② In the middle of layer 4, potassium and calcium separated again, but the overall calcium content was higher than in sub-section 2. ③ In the lower part of layer 4, gamma decreased steadily overall, aluminum and silicon converged, and potassium and calcium converged again. ④ In layer 3, gamma increased, with an overall peak-like gamma, a smaller aluminum-silicon convergence area, and potassium-calcium bifurcation; ⑤ In layer 2, the overall gamma value was low, with a secondary peak in the upper middle part, and the gamma initially decreased slowly before slowly increasing upon entering the box-shaped area; ⑥ In layer 1, gamma showed a bimodal shape, with a higher gamma value than the peak in layer 3. Figure 1 )

[0054] (3) Horizontal Segment Trajectory Design. By slicing the 3D seismic data along the well trajectory, the dip angle of the formation is extracted segment by segment to establish a structural model; then, the box parameters of the horizontal well reservoir (true vertical thickness, lateral distribution, etc.) are predicted, and a reservoir model is established using the reservoir modules of each region integrated in the software; a three-dimensional geological steering model is established before drilling by integrating the reservoir model and the structural model, and the well trajectory is optimized according to the changes in the vertical and horizontal directions of the reservoir; the applicability analysis of micro-fault and curvature location prediction is carried out based on the superposition of different seismic attributes; the data change characteristics of the encountered faults and curvature locations are statistically analyzed, and a fine characterization is carried out using fitting technology to establish a fine ant-shaped geological model, and micro-fracture prediction is performed in the well area, providing a direct reference for the drilling trajectory scheme and providing early warning of engineering complexity for drilling. Figure 2 )

[0055] Step 3: Precise Landing and Target Entry. Based on the guidance plan and the characteristics of different marker layers, the vertical depth and dip angle of the landing section are determined, forming the "six elements of effective control methods" for landing section target entry. These include: ① understanding the target entry design requirements, ② analyzing the characteristics of different box-type sub-layers, ③ mastering the structural changes of target point A, ④ analyzing the elemental characteristics of marker layers, ⑤ calculating the vertical depth of target point A, and ⑥ revising the landing plan design. Currently, the main problems and difficulties in the landing section are as follows: when the landing section enters sub-layer No. 4, the actual formation thickness of multiple adjacent wells varies greatly, with the thickness between wells on each platform ranging from 20m to 48m, causing difficulties in target entry.

[0056] Therefore, the reasons for the variations in the thickness of the four sub-layers in the landing section have been clarified, including factors such as faults of different scales, flexural zones, sedimentary phenomena, and stratigraphic dip. Preliminary findings indicate that the variations in the thickness of the four sub-layers are mainly due to two factors:

[0057] (1) When drilling encounters a flexural zone, the dip angle of the strata in the landing section changes from updip to downdip, resulting in a difference between the true thickness and apparent thickness of the strata in the landing section.

[0058] ① When the formation dips upwards (the dip angle exceeds 5 degrees), it can be determined that the true thickness (h) of the formation is greater than the apparent thickness (h1). Affected by this, the No. 4 sub-layer was mistakenly judged to be thinner. To prevent it from penetrating the bottom of the box during target entry, a large dogleg angle was used to increase the inclination, ensuring a smooth wellbore. The elements were combined with the marker layer comparison during drilling to clarify the formation dip angle change pattern, and the consistency with the directional plan was analyzed. The vertical depth change characteristics of the target entry point were closely tracked during drilling, and trajectory adjustments were implemented to achieve accurate target entry.

[0059] ② When encountering a downdipping formation (formation dip angle exceeding 5 degrees), the true formation thickness (h) is less than the apparent formation thickness (h1). To achieve precise target entry, a stable dogleg depth is used for probing, and the specific position of the drill bit is determined by analyzing the marker layer and making real-time adjustments. The operability of the directional plan is analyzed, and elements are combined with a fine comparison of adjacent wells (or pilot wells) using drilling GR to accurately determine the vertical depth of the landing point, clarify the formation dip angle variation pattern, and adjust the trajectory in real time to achieve precise landing and target entry.

[0060] (2) Due to the influence of seismic data, there is a great difference between the seismic axis and the actual drilling trajectory. The landing section often encounters reverse faults of different scales. Through the different orientations of the faults and the well trajectory, the formation may be repeated or missing. Therefore, the faults of different scales affect the thickness or thinning of the No. 4 sub-layer.

[0061] ① When the well trajectory is in the same direction as the fault, the thickness will become thinner when the well trajectory passes through the downthrown strata of the fault due to the influence of the fault dip.

[0062] ② When the well trajectory is opposite to the fault, the formation repeats itself when the well trajectory passes through the downthrown strata due to the influence of the fault dip, resulting in an increase in formation thickness.

[0063] By combining formation correlation with formation dip angle to predict the target depth while drilling, the target trajectory is adjusted in real time. If the marker layer in the plan is encountered ahead of schedule, the target depth needs to be recalibrated and the trajectory adjusted to ensure successful target entry. If the predetermined well inclination is reached but the marker layer is not reached, the well needs to be steadily lowered until the marker layer is reached, and then the target depth is re-predicted. The trajectory is adjusted in time to avoid backfilling and exceeding the designed target distance. Factors such as flexural zones, faults, and formation dip are analyzed in a timely manner. Close tracking, accurate judgment, and timely adjustments are made to ultimately achieve accurate landing and target entry.

[0064] Step 4: Precise Adjustment of the Horizontal Section. After the landing section accurately hits the target, horizontal directional tracking is carried out. Using well logging and drilling GR information from this well and adjacent wells, the position of the trajectory within the box is precisely analyzed, the formation dip angle is calculated, the trajectory's vertical tangency is determined, and the trend of formation dip angle changes within the box is predicted with reference to seismic data. All of the above information is comprehensively used to precisely adjust the trajectory, ensuring smooth drilling within the box. This requires both ensuring the box penetration rate and rationally optimizing the trajectory adjustment to guarantee drilling safety.

[0065] (1) Determining the position of the horizontal segment trajectory

[0066] Accurately determining the well trajectory's position within the box is crucial for timely trajectory adjustments, ensuring it remains within the box. Based on the previously established box selection criteria, the drilling GR and elemental logging characteristics of sub-layers 1, 2, and 3 within the box are clearly defined. Layer 1 exhibits a distinctly high and pointed GR value, ranging from 300 to 500, with almost no aluminum-silicon junctions but a large potassium-calcium junction area. Layer 2 has a GR value between 250 and 270, with relatively large aluminum-silicon and potassium-calcium junctions; the GR gradually increases from top to bottom, with a significantly larger silicon-calcium junction area at the top than at the bottom. Layer 3 also shows a distinctly high and pointed GR value between 250 and 450, with small aluminum-silicon and potassium-calcium junctions and a large silicon-calcium junction area. Understanding the gamma ray variation characteristics of the box and surrounding sub-layers is essential for accurately determining the drill bit position and precisely adjusting the trajectory.

[0067] (2) Calculation of dip angle of strata in horizontal section

[0068] The key to calculating the dip angle of the formation in the horizontal section is to identify two points A and B in the actual drilling trajectory that are in the same or similar positions within the box formation. When the well trajectory cuts downwards from layer 2 to point A at the gamma peak of layer 1, it enters the WF group. After increasing the inclination, the trajectory cuts upwards again, passing through point B at the peak of layer 1, and returns to layer 2, entering the box formation. Points C and D, and E and F, are also in similar positions within the box formation. Based on the angle between the line connecting these two similar points and the horizontal plane, the dip angle θ of the formation within the box formation is calculated. The formula is θ = arctan(vertical depth difference between B and A / apparent translation difference between B and A). A positive θ indicates a downdip formation, and a negative θ indicates an updip formation. Figure 3 )

[0069] (3) Trajectory tangency analysis

[0070] When abnormalities occur in the gamma and elemental characteristics of the well trajectory during drilling in the horizontal section, it indicates that the position of the well trajectory in the box has changed. Accurate and timely judgment of whether the trajectory is cutting upward or downward into the formation can determine whether the directional command should be to reduce or increase the inclination, thereby reducing the loss in the horizontal section.

[0071] The trajectory cuts down through the formation, from the second sub-layer through the first sub-layer into the WF group. Gamma curve characteristics and elemental logging show the following: In the upper half of the formation, the gamma ray increases overall, with the lower gamma always greater than the upper gamma; after passing the peak of the first sub-layer, the cutting continues into the lower half, where the gamma ray decreases overall, with the upper and lower gamma values ​​converging at the peak, resulting in the lower gamma always being less than the upper gamma. Elemental characteristics include decreased silicon and increased calcium; no intersection area between silicon and aluminum; a larger intersection area between potassium and calcium; and a step-like pattern in zirconium. Figure 4 )

[0072] The trajectory cuts through the formation, starting from the WF group, passing through one sub-layer, and returning to the second sub-layer. The upper and lower gamma ray and elemental characteristics are exactly the opposite of those when the trajectory cuts downwards. This example illustrates how to use upper and lower gamma rays to determine the formation cut by the trajectory. The same applies to entering other sub-layers. By using upper and lower gamma ray characteristics and elemental characteristics to determine the upper and lower cut of the well trajectory, the trajectory position and changes in formation dip angle can be determined, allowing for timely adjustments and optimization of the trajectory to ensure a high drilling success rate.

[0073] (4) Horizontal segment guidance tracking

[0074] Horizontal section directional tracking is used for precise trajectory adjustment in complex formations. Currently, more than 40 horizontal wells have been drilled in the study area. Based on the drilling conditions of the horizontal sections of each horizontal well, the principles for precise adjustment of complex sections are summarized as follows: For complex horizontal sections that often encounter "flexure, faults, and box-shaped hard layers", the actual drilling trajectory is closely tracked, and the formation dip angle is determined by using rotary guide GR and element logging. The well deviation range is controlled, and adjustments are made in real time by comparing with the drilling. The "5-step adjustment principle for complex sections" is established to improve the drilling rate of horizontal sections.

[0075] ① The formation is stable, so we can make minor adjustments and continue drilling to follow the formation.

[0076] ② The angle between the micro-structures, small faults, and the hard layer at the top of the box-shaped structure and the subsequent strata should be kept within 3°.

[0077] ③ The drilling process was stabilized by optimizing the secondary landing method for large faults;

[0078] ④ Drill into the favorable target area ahead of the complex section;

[0079] ⑤ Drilling in complex structural sections by tracking the formation trends of the actual drilling on the same platform.

[0080] The embodiments described above are merely preferred embodiments of the present invention, and not all feasible embodiments of the present invention. Any obvious modifications made by those skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. A geological steering method for deep shale gas horizontal wells based on multi-source information fusion, characterized in that, Includes the following steps: S1. Box Selection: Select horizontal target layers, determine reservoir thickness, combine elemental characteristics to determine box thickness, and clarify roadway location; S2. Guiding Plan Modeling: Developing a directional drilling plan for horizontal wells; S3. Precise landing and target entry: Determine the vertical depth and inclination of the landing segment, develop an effective control method for the landing segment's target entry, and clarify the reasons for the changes in the thickness of the sublayer in the landing segment; S4. Precise Adjustment of Horizontal Section: Closely track the actual drilling trajectory on site, accurately analyze the position of the trajectory within the box, calculate the dip angle of the strata, determine the trajectory relationship, clarify the box information, and comprehensively utilize the above information to precisely adjust the trajectory.

2. The geological steering method for deep shale gas horizontal wells based on multi-source information fusion according to claim 1, characterized in that, Step S1 specifically involves: selecting platinum target layers for horizontal wells and determining the thickness of Class I reservoirs; based on the thickness of Class I reservoirs and combined with elemental characteristics, determining the box thickness, clarifying the roadway location, and determining the platinum target layers for horizontal wells according to data parameters.

3. The geological steering method for deep shale gas horizontal wells based on multi-source information fusion according to claim 2, characterized in that, In step S1, select a gas content greater than 5m 3 A horizontal well platinum target layer is defined as having brittle minerals greater than 65%, porosity greater than 5%, organic carbon greater than 4%, gas saturation greater than 65%, Poisson-Poisson brittleness index greater than 50%, and clay content less than 20%.

4. The geological steering method for deep shale gas horizontal wells based on multi-source information fusion according to claim 1, characterized in that, Step S2 specifically involves: using drilling data from adjacent wells and combining it with seismic data to develop a directional drilling plan for the horizontal well; the directional drilling plan consists of three parts: target depth prediction, landing trajectory design, and horizontal trajectory design.

5. The geological steering method for deep shale gas horizontal wells based on multi-source information fusion according to claim 4, characterized in that, The specific guiding construction plan for step S2 is as follows: A. Target depth prediction: The formation data of the drilling section is compared with that of the regional vertical well. The formation dip angle of the target point is predicted by combining seismic data. The target depth is predicted by correcting the formation thickness and formation dip angle. The target trajectory is then redesigned and optimized. B. Landing Segment Trajectory Design: The strata of the entire landing segment are finely divided by analyzing the gamma and elemental energy spectrum characteristics of adjacent wells. Six marker layers with obvious and stable gamma and elemental characteristics are selected. Six control points are planned from top to bottom during the landing process, and the layers are approached one by one. C. Horizontal Segment Trajectory Design: By slicing 3D seismic data along the well trajectory, the dip angle of the formation is extracted segment by segment to establish a structural model; then, the box parameters of the horizontal well reservoir are predicted, and a reservoir model is established using the reservoir modules of each region integrated in the software; a pre-drilling 3D geological steering model is established by integrating the reservoir model and the structural model, and the well trajectory is optimized based on the vertical and horizontal changes of the reservoir; an applicability analysis of micro-fault and curvature location prediction is conducted based on the superposition of different seismic attributes; the data variation characteristics of encountered faults and curvature locations are statistically analyzed, and fitting technology is used for fine characterization to establish a fine ant-like geological model, predict micro-fractures in the well area, provide direct reference for the drilling trajectory scheme, and provide early warning of engineering complexities for drilling.

6. The geological steering method for deep shale gas horizontal wells based on multi-source information fusion according to claim 1, characterized in that, Step S3 specifically involves: determining the vertical depth and dip angle of the landing segment based on the characteristics of different marker layers, forming the "six elements of effective control methods for landing segment target entry"; and clarifying the reasons for the changes in the thickness of the sublayers in the landing segment, including faults of different scales, flexural zones, sedimentary phenomena, and stratigraphic dip factors.

7. The geological steering method for deep shale gas horizontal wells based on multi-source information fusion according to claim 6, characterized in that, The "six elements of effective control method" in step S3 are as follows: ① understanding the target entry design requirements, ② analyzing the characteristics of different box-shaped sub-layers, ③ mastering the structural changes of target point A, ④ analyzing the characteristics of marker layer elements, ⑤ calculating the vertical depth of target point A, and ⑥ revising the landing scheme design.

8. The geological steering method for deep shale gas horizontal wells based on multi-source information fusion according to claim 6, characterized in that, Step S3 clarifies the reasons for the changes in the thickness of the sublayer in the landing section, including faults of different scales, flexural zones, sedimentary phenomena, and stratigraphic dip factors. It clarifies that the changes in the sublayer thickness are caused by two main factors: When drill a encounters a flexural zone, the dip angle of the strata in the landing section changes with updip and downdip, resulting in a difference between the true thickness and apparent thickness of the strata in the landing section. b. Due to the influence of seismic data, there is a great difference between the seismic axis and the actual drilling trajectory. The landing section often encounters reverse faults of different scales. Through the different orientations of the faults and the well trajectory, the formation may be repeated or missing. Therefore, faults of different scales can cause the sub-layers to become thicker or thinner.

9. The geological steering method for deep shale gas horizontal wells based on multi-source information fusion according to claim 1, characterized in that, Specifically, step S4 involves closely tracking the actual drilling trajectory in complex horizontal sections, accurately determining the location of the box within the trajectory, calculating the formation dip angle, judging the vertical tangent relationship of the trajectory, clarifying the box element logging and drilling GR information, and comprehensively utilizing the above information to precisely adjust the trajectory.

10. The geological steering method for deep shale gas horizontal wells based on multi-source information fusion according to claim 9, characterized in that, The information obtained in step S4 specifically includes: horizontal segment trajectory position determination, horizontal segment stratum dip angle calculation, trajectory vertical tangency analysis, and horizontal segment guidance tracking.

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