Shale gas horizontal well geophysical steering method and apparatus

Abstract

The present application provides a shale gas horizontal well geophysical orientation method and device. Compared with the prior art, the present application solves the problem that the subsequent formation depth and occurrence of the horizontal well cannot be predicted by relying on geosteering alone, and is dynamically adjusted, which can guarantee the high-speed drilling of the shale gas horizontal well, improves the drilling rate of high-quality shale, saves cost, provides support for high-quality exploration and development of shale gas, and is beneficial to guarantee energy security.

Description

Technical Field

[0001] The present invention relates to the field of shale gas exploration and development, and in particular to a shale gas horizontal well geophysical guidance method and device. Background Art

[0002] Shale gas horizontal well guidance is a key link in shale gas development and an important guarantee for the economic benefits of shale gas exploration and development. High-quality horizontal well guidance can ensure that the horizontal well trajectory always passes through the target window in the high-quality shale section, thereby achieving high yield in the subsequent fracturing. If the horizontal well guidance quality is poor, the well trajectory is likely to pass through the non-high-quality shale section, resulting in the inability to achieve high yield after the horizontal well is drilled and fracturing, and thus the inability to effectively develop shale gas.

[0003] Current shale gas horizontal well guidance mainly relies on gamma, resistivity, and density measurements obtained by a rotary steerable drill bit to infer the current shale formation's occurrence and depth, thereby achieving steering control. Rotary steerable drill bit technology lacks predictive power for subsequent formations after horizontal well drilling, and can only perform backward corrections based on current point information. It reacts slowly to sudden changes in formations and cannot locate detailed formation structures and small faults, resulting in limited steering accuracy. Even with the use of a structural map of the study area as an aid, the complex and variable structure can lead to significant differences between actual drilling and the initial structural map. For example, sudden changes in occurrence and small folds in subsequent shale formations can easily cause the horizontal well trajectory to deviate from the target window of the high-quality shale section, resulting in poor fracturing results for shale gas horizontal wells and no economic benefits for exploration and development. Summary of the Invention

[0004] In view of this, the present invention aims to propose a shale gas horizontal well geophysical guidance scheme that dynamically predicts the subsequent stratum burial depth and production conditions of the horizontal well trajectory to adjust the horizontal well trajectory in real time, which can increase the drilling rate of high-quality shale sections in horizontal wells, improve drilling efficiency and save costs.

[0005] According to one aspect of the present invention, a shale gas horizontal well geophysical guidance method is proposed, the method comprising:

[0006] Step 1: Obtain an initial velocity model of the study area, and use the initial velocity model to perform time-depth conversion on fault characteristics and horizon characteristics to obtain an initial shale stratigraphic structure map;

[0007] Step 2: designing an initial drilling plan based on the initial shale formation structure map;

[0008] Step 3: Perform drilling operations and collect logging curves of the drilling. After the drilling operation distance reaches the preset drilling length, compare the collected logging curves of the drilling with the logging curves of adjacent wells to obtain the formation depth and occurrence at the drill bit position;

[0009] Step 4, updating the velocity model by adding the newly acquired formation depth and occurrence, updating the velocity model, and updating the current shale formation structure map using the updated velocity model;

[0010] Step 5, predicting whether there is a mutation and whether there is a special detail structure in the formation along the horizontal well trajectory within the subsequent preset drilling length based on the updated shale formation structure map;

[0011] Step 6, designing the bit direction of the further drilling operation based on the prediction.

[0012] In some embodiments, before the step 1, the method further comprises establishing an initial velocity model by the following method:

[0013] Using seismic data, performing fine structure interpretation to obtain shale reservoir fault characteristics and horizon characteristics;

[0014] Combining the well logging curve, well logging layering, fault characteristics and horizon characteristics, establishing an initial velocity model for time-depth conversion.

[0015] In some embodiments, if it is predicted that there is a mutation and / or there is a special detail structure in the formation along the horizontal well trajectory within the subsequent preset drilling length, in the step 6, the bit direction is adjusted based on the prediction.

[0016] In some embodiments, the method further comprises:

[0017] During the drilling operation, the velocity model and the shale formation structure map are updated every preset drilling length, and whether there is a mutation and whether there is a special detail structure in the formation along the horizontal well trajectory within the subsequent preset drilling length is predicted based on the updated shale formation structure map, and the bit direction of the further drilling operation is designed based on the prediction.

[0018] In some embodiments, the range of the preset drilling length is 10m-30m.

[0019] In some embodiments, the collected well logging curve of the drilling includes a gamma curve, a resistivity curve, a sonic curve and a density curve.

[0020] According to another aspect of the present application, a shale gas horizontal well geophysical prospecting guiding device is also provided, which comprises:

[0021] An initial model acquisition unit is configured to obtain an initial velocity model of a study area, and to perform time-depth conversion on fault characteristics and horizon characteristics using the initial velocity model to obtain an initial shale formation structure map;

[0022] An initial scheme design unit is configured to design an initial drilling scheme based on the initial shale formation structure map;

[0023] a while-curve collecting unit configured to perform a drilling operation and collect well logging curves of the drilling operation, and compare the collected well logging curves of the drilling operation with well logging curves of a neighboring well to obtain a formation depth and occurrence of a drill bit position after a distance of the drilling operation reaches a preset drilling length;

[0024] a model updating unit configured to add the newly obtained formation depth and occurrence to a current velocity model, update the velocity model, and update a current shale formation structure map using the updated velocity model;

[0025] a trajectory predicting unit configured to predict whether a formation along a horizontal well trajectory in a subsequent preset drilling length has a sudden change and / or a special detailed structure based on the updated shale formation structure map;

[0026] a steering design unit configured to design a drill bit direction for a further drilling operation based on the prediction.

[0027] In some embodiments, the apparatus further comprises:

[0028] a fine structure interpretation unit configured to perform fine structure interpretation using seismic data to obtain shale reservoir fault features and horizon features;

[0029] an initial velocity model establishing unit configured to establish an initial velocity model for time-depth conversion in combination with the well logging curves, well logging layering, fault features and horizon features.

[0030] In some embodiments, if the formation along the horizontal well trajectory in the subsequent preset drilling length is predicted to have a sudden change and / or a special detailed structure, the steering design unit adjusts the drill bit direction based on the prediction.

[0031] In some embodiments, the while-curve collecting unit, the model updating unit, the trajectory predicting unit and the steering design unit are repeatedly invoked during the drilling operation.

[0032] In some embodiments, the preset drilling length ranges from 10m to 30m.

[0033] In some embodiments, the collected well logging curves of the drilling operation include gamma curves, resistivity curves, sonic curves and density curves.

[0034] According to another aspect of the present application, an electronic device is also provided, which comprises:

[0035] a memory storing executable instructions;

[0036] a processor configured to execute the executable instructions in the memory to implement the shale gas horizontal well geophysical steering method described above.

[0037] According to another aspect of the present application, there is also provided a computer readable storage medium storing a computer program which, when executed by a processor, implements the shale gas horizontal well geophysical direction method described above.

[0038] The present application has at least the following benefits:

[0039] (1) The drilling rate of the shale gas horizontal well is improved, and the horizontal section trajectory is ensured to be located in the high-quality production section.

[0040] (2) The dynamic prediction of the stratum in the un-drilled area is realized, and the forward-looking of the direction is greatly improved.

[0041] (3) Multi-source information is used to enhance data constraints, so that the direction result is more accurate and reliable.

[0042] (4) The automatic, intelligent and fine direction process is realized, and the uncertainty caused by manual experience is reduced.

[0043] (5) The whole direction system reacts quickly, and can realize dynamic real-time adjustment, so that the direction efficiency is greatly improved.

[0044] (6) The rework and red drilling caused by deviating from the target layer are reduced or avoided, and the development cost is reduced.

[0045] (7) The direction system is flexible, and can adapt to complex geological conditions, so that the dependence on geological prediction is reduced.

[0046] (8) It is beneficial to realize the efficient development of shale gas, improve the single well production, and reduce the comprehensive development cost.

[0047] (9) The application of the direction technology is beneficial to promote the rapid development of the shale gas industry.

[0048] (10) It has important significance for ensuring energy security and promoting unconventional oil and gas revolution.

[0049] The method and device of the present application have other characteristics and advantages, which will be apparent or will be described in detail in the accompanying drawings and subsequent detailed description incorporated herein, which together serve to explain the specific principles of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0050] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout the several views, and wherein the exemplary embodiments of the present application are shown.

[0051] Figure 1 A flow chart of a shale gas horizontal well geophysical direction finding method according to one embodiment of the present application is shown. DETAILED DESCRIPTION

[0052] Preferred embodiments of the present application will be described in greater detail below with reference to the accompanying drawings. While the preferred embodiments of the present application are shown in the drawings, it is understood that the present application can be carried out in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the application to those skilled in the art.

[0053] Example 1

[0054] In order to make the purposes, technical solutions and advantages of the present application clearer, the following takes a shale gas horizontal well in a certain area as an example, the research area is a favorable area for shale gas exploration, but during the drilling of the shale gas horizontal well, due to the complex structure, the quick change of the shale formation depth and occurrence, the drilling speed of the horizontal well is affected. Taking the JY10 well in the area as an example, a detailed exemplary description of the present application is first made.

[0055] Step one: carry out structural interpretation on the three-dimensional seismic data in the area, and implement that the overall shale storage fault in the area is in the north-east direction.

[0056] Step two: combine the curves of the drilled JY194-3, JY195-2, SY1, NY1 and other wells in the area, carry out well logging layering, interpret the faults, horizons and processing velocities, and establish an initial velocity model of time-depth conversion.

[0057] Step three: use the time-depth conversion model to compile an initial shale formation structure map of the Longmaxi Formation, and implement that the overall high-quality shale of the Longmaxi Formation is buried at 900 to 6500 meters.

[0058] Step four: design the target point of the shale gas horizontal well JY10HF well according to the initial shale formation structure map and the ground conditions, and design the A target point of the JY10HF well to be 3410 meters in vertical depth, and start drilling.

[0059] Step five: after the JY10HF horizontal well enters the designed target point, collect the gamma, resistivity, acoustic wave, density and other data of the logging while drilling, at this time the actual drilling target point is 3443 meters in vertical depth (3662 meters in depth), the occurrence of the formation is 6.6° in inclination, and there is a certain error between the design and the actual drilling.

[0060] Step six: add the obtained formation depth information and occurrence information to the initial velocity model, update the velocity model, use the new velocity model to carry out time-depth conversion on the interpreted horizons and faults, and compile a new shale formation structure map.

[0061] Step seven: From the new shale formation structure map, it is found that the depth and formation occurrence of the subsequent 20-meter horizontal well trajectory formation have changed, and the vertical depth at the next 20-meter point is 3447.6 (measured depth 3682 meters), which is 1.3 meters deeper than the original design, and the formation is steeper than the original design.

[0062] Step eight: During the horizontal well drilling process of JY10 well, the velocity model is updated every 20 meters, and the shale formation structure map is recompiled to predict the subsequent formation depth and occurrence, thereby ensuring high-speed drilling of the horizontal well.

[0063] JY10 well uses a horizontal well guiding method combined with geophysical prospecting, and the length of the horizontal section from A target point to B target point is 1542 meters, which is drilled in 13 days at a cost of 7.13 million yuan. Compared with JY207-1 well in the same structure, which used only a geological guiding method, the horizontal section is 1620 meters long, which takes 19 days and costs 9.35 million yuan. The efficiency has been significantly improved, and the drilling speed has increased by about 38% from 85 meters per day to 118 meters per day. Due to the improvement in drilling efficiency, the cost has also been significantly reduced from 5700 yuan per meter to 4600 yuan per meter.

[0064] Other detailed descriptions related to the present exemplary embodiment can be referred to the corresponding descriptions in the following embodiments, which will not be repeated here.

[0065] Example 2

[0066] Figure 1 A flowchart of a shale gas horizontal well geophysical prospecting guiding method according to one embodiment of the present application is shown, which includes steps 1-6.

[0067] Step 1, obtain the initial velocity model of the study area, and use the initial velocity model to perform time-depth conversion of fault features and horizon features to obtain an initial shale formation structure map.

[0068] In some embodiments, the initial velocity model can be obtained by the following method:

[0069] Using seismic data, fine structure interpretation is performed to obtain shale reservoir fault features and horizon features;

[0070] Combined with logging curves, logging layering, fault features and horizon features, an initial velocity model for time-depth conversion is established.

[0071] Shale gas reservoirs are mainly located in shale formations, and shale itself has very low porosity and permeability, which needs to rely on natural fractures for storage and migration. Among these natural fractures, the fractures associated with faults have better connectivity, so the shale reservoir faults are the faults developed in the shale reservoir or the boundary thereof, and the fracture network in these faults plays a key role in the accumulation and migration of shale gas.

[0072] The fault features of the shale reservoir fault can include:

[0073] The location and trend of the fault: confirming the location of the fault plane in space and the extension direction of the fault;

[0074] The dip of the fault: the dip angle of the fault, whether it is vertical or oblique;

[0075] The nature of the fault: whether it is a normal fault, a reverse fault or a cross fault;

[0076] The extent of the fault: the length of the fault, whether it penetrates the entire target layer;

[0077] The width of the fault zone: the size of the fracture zone in the fault zone.

[0078] The stratigraphic features of the shale reservoir fault can include:

[0079] The upper and lower boundaries of the layer: the top and bottom boundaries of the target reservoir layer;

[0080] The thickness of the layer: the statistics of the overall thickness of the reservoir;

[0081] The burial depth of the layer: determining the depth information of the reservoir;

[0082] The occurrence of the layer: the overall tendency direction of the reservoir;

[0083] The internal fine structure of the layer: small folds, small fault blocks and other structures within the layer.

[0084] The initial velocity model for establishing time-depth conversion can generally include the following steps:

[0085] (1) Collect the required data: well logging curves, well logging results, fault features and stratigraphic features of the study area, etc.

[0086] (2) Correlate and compare the well logging curves to determine the correlation relationship between the wells.

[0087] (3) On the basis of correlation, determine the time-depth relationship of the stratigraphic boundaries.

[0088] (4) Collect or test the acoustic velocity parameters of each formation.

[0089] (5) Digitize and organize the above data into a computer.

[0090] (6) Specific software can be used, such as Schlumberger's Petrel, CGG's Hampson-Russell, SMT's Kingdom, to establish the velocity model for time-depth conversion.

[0091] The velocity model can include the top and bottom board time or depth of each layer, velocity parameters and other information, and the velocity model is usually checked to ensure the consistency of the time-depth relationship of each layer.

[0092] Common algorithms for establishing the velocity model for time-depth conversion include grid method, velocity perturbation method, multi-parameter joint inversion and genetic algorithm, particle swarm optimization algorithm and other intelligent algorithms.

[0093] According to the data source integration of the embodiment, multi-source information such as seismic data, logging data and geological data is organically combined, the constraint of velocity field simulation is enhanced, and high-quality velocity model is obtained, which lays a foundation for subsequent accurate steering calculation.

[0094] The time-depth conversion of the interpreted layer using the velocity model can include:

[0095] According to the velocity model, the corresponding actual depth of each layer interface at the depth is calculated;

[0096] Connecting the actual depth points of the same layer on different lines can obtain the depth structure diagram of the layer.

[0097] The time-depth conversion of the fault using the velocity model can include:

[0098] According to the time position of the fault in the seismic profile, the actual depth position is calculated;

[0099] Connecting the actual depth of the fault on different lines can draw the three-dimensional spatial position of the fault.

[0100] Thus, the initial shale formation structure diagram can be obtained by using the initial velocity model to perform time-depth conversion on the fault features and layer features.

[0101] The obtained initial formation structure diagram can include the following information: the top and bottom interfaces of each formation, and the absolute depth value; the dip of the formation, expressing the occurrence of the formation; the position and nature of the fault; the design of the drilling path; the distribution range of the profitable layer or target layer. Thus, the basis for subsequent design of drilling scheme is provided.

[0102] Step 2, design the initial drilling scheme based on the initial shale formation structure diagram.

[0103] The target point of a shale gas horizontal well can be designed based on the initial shale formation structure map obtained in step 1. The target point of a horizontal well is the design target point of the horizontal section position, which is an area usually defined by a longitude and latitude range (e.g., a rectangular area). When designing shale gas / oil horizontal well drilling, it is necessary to first determine the position of the horizontal section, i.e., the target point. According to the present invention, the most favorable production layer position can be selected as the target point based on the formation structure map, and the block with large thickness and high porosity in the production layer shown in the formation structure map can be determined as the target point, and drilling can begin.

[0104] Step 3: Perform drilling operations and collect logging curves of the drilling. After the drilling operation distance reaches the preset drilling length, compare the collected logging curves of the drilling with the logging curves of adjacent wells to obtain the formation depth and occurrence at the drill bit position.

[0105] After the horizontal well is drilled into the target point, a logging curve while drilling can be collected. In some embodiments, the collected logging curves include gamma curves, resistivity curves, sonic curves, and density curves.

[0106] After the drilling operation reaches a preset drilling distance—for example, 20 meters in one example—the collected well logs can be compared with those of adjacent wells to determine the formation depth and occurrence at the drill bit location. The occurrence primarily refers to the strike and dip of the formation, reflecting its overall orientation. Determining the occurrence is crucial for clarifying its spatial position and structural deformation.

[0107] Step 4: Add the newly acquired formation depth and occurrence to the current velocity model to update the velocity model, and use the updated velocity model to update the current shale formation structure map.

[0108] In this embodiment, when the drilling operation reaches a certain distance, the shale formation structure map is updated in a timely manner based on the formation depth and occurrence at the latest drill bit position, thereby realizing dynamic prediction of the formation in the undrilled area and greatly improving the foresight of subsequent guidance.

[0109] Step 5: Based on the updated shale formation structure map, it is predicted whether there is a sudden change in the formation along the horizontal well trajectory within the subsequent preset drilling length and whether there is a special detailed structure.

[0110] Stratigraphic abrupt changes may include abrupt changes in stratum depth and / or stratum attitude. Special detailed structures may include micro-folds and / or small faults within the stratum.

[0111] If the subsequent horizontal well trajectory passes through an area with sudden formation changes and / or special detailed structures, it is very easy for the horizontal well to deviate from the target window of the high-quality shale section, resulting in poor fracturing effect of the shale gas horizontal well and no economic benefits for exploration and development.

[0112] The existing rotary steerable bit technology can only make backward correction according to current point information, and has slow response to sudden changes in strata, and cannot locate the detailed structure and small fractures of the strata, and the guiding precision is limited. Even if the structure map of the research area is used as an auxiliary, due to the complex and variable structure, the actual drilling and the initial structure map are greatly different. In the embodiment, the shale structure map is updated in time according to the drilled part, the strata changes of the undrilled part can be accurately and dynamically predicted, and the whole guiding system can quickly respond. Especially in the mining environment of complex geological conditions, the beneficial effects of the embodiment relative to the prior art are more significant.

[0113] Step 6: Based on the prediction, the direction of the drill bit for the further drilling operation is designed.

[0114] If the prediction result shows that there is no sudden change and / or special detailed structure in the strata along the horizontal well trajectory within the subsequent preset drilling length, the drilling can continue along the originally designed direction of the drill bit.

[0115] If the prediction shows that there is a sudden change and / or special detailed structure in the strata along the horizontal well trajectory within the subsequent preset drilling length, the direction of the drill bit can be adjusted to ensure that the horizontal section trajectory is always located in the high-quality production section, improve the drilling rate of the shale gas horizontal well, reduce the cost, and improve the economic benefit.

[0116] In some embodiments, during the drilling operation, the velocity model and the shale strata structure map can be updated every preset drilling length, and whether there is a sudden change and / or special detailed structure in the strata along the horizontal well trajectory within the subsequent preset drilling length is predicted based on the updated shale strata structure map, and the drilling scheme for the subsequent preset drilling length is designed based on the prediction result.

[0117] That is, during the drilling operation, the above steps 3 to 6 are repeatedly executed, and the dynamic prediction of the strata in the current undrilled area is realized throughout the process, so that the whole guiding system can quickly respond, the guiding efficiency is significantly improved, and the horizontal section trajectory is always located in the high-quality production section.

[0118] The preset drilling length is too long, which may cause the guiding system to be not sensitive enough, and too short, which may affect the drilling speed. After in-depth research, the inventors believe that in some examples, the range of the preset drilling length can be 10m-30m. For example, the preset drilling length can be set to 20 meters (m).

[0119] In summary, the shale gas horizontal well geophysical guiding method provided by the embodiment solves the problem that the current geological guiding cannot predict the subsequent strata depth and occurrence of the horizontal well, and the embodiment adopts dynamic adjustment to ensure high-speed drilling of the shale gas horizontal well, which improves the drilling rate of high-quality shale, saves cost, provides support for high-quality exploration and development of shale gas, and is conducive to ensuring national energy security.

[0120] Example 3

[0121] One embodiment of the present application discloses a shale gas horizontal well geophysical orientation device. The device comprises:

[0122] An initial model acquisition unit is configured to obtain an initial velocity model of a study area, and convert time and depth of fault features and horizon features by using the initial velocity model to obtain an initial shale formation structure map;

[0123] An initial scheme design unit is configured to design an initial drilling scheme based on the initial shale formation structure map;

[0124] A while-drilling curve collection unit is configured to perform a drilling operation and collect well logging curves of the drilling, and compare the collected well logging curves of the drilling and well logging curves of a neighboring well to obtain a formation depth and occurrence of a drill bit position after a distance of the drilling operation reaches a preset drilling length;

[0125] A model updating unit is configured to add the newly obtained formation depth and occurrence to a current velocity model, update the velocity model, and update a current shale formation structure map by using the updated velocity model;

[0126] A trajectory prediction unit is configured to predict whether a mutation and a special detailed structure exist in a formation along a horizontal well trajectory within a subsequent preset drilling length based on the updated shale formation structure map;

[0127] A steering design unit is configured to design a drill bit direction of a further drilling operation based on the prediction.

[0128] In the initial model acquisition unit, the time and depth conversion of the interpreted horizons by using the velocity model can include:

[0129] According to the velocity model, a corresponding actual depth of each horizon interface at a depth is calculated;

[0130] Connecting the actual depth points of the same horizon on different lines can obtain a depth structure map of the horizon.

[0131] The time and depth conversion of the faults by using the velocity model can include:

[0132] According to the time position of the faults in a seismic profile, an actual depth position is calculated;

[0133] Connecting the actual depths of the faults on different lines can draw a three-dimensional spatial position of the faults.

[0134] Thus, the initial velocity model can be used to convert time and depth of the fault features and the horizon features to obtain the initial shale formation structure map.

[0135] In the initial scheme design unit, the target point of the shale gas horizontal well can be designed according to the obtained initial shale formation structure map. The target point of the horizontal well is a design target point of the horizontal section position, which is an area (for example, a rectangular area) usually defined by a latitude and longitude range. When the shale gas / oil horizontal well drilling design is performed, the position of the horizontal section, that is, the target point, needs to be determined first. According to the present application, the most favorable production layer position can be selected as the target point according to the formation structure map, and a block with large thickness and high porosity in the production layer shown in the formation structure map can be determined as the target point, and drilling can be started.

[0136] After the horizontal well drilling enters the target point, the while-drilling curve collection unit can collect the while-drilling logging curves. In some embodiments, the collected drilling logging curves include gamma curves, resistivity curves, sonic curves, and density curves, etc.

[0137] Through the model updating unit, after the drilling operation distance reaches a preset drilling length, for example, in one example, after the drilling operation distance reaches 20 meters, the formation depth and occurrence of the drill bit position can be obtained by comparing the collected drilling logging curves and the logging curves of the adjacent well. The occurrence mainly refers to the trend and dip of the formation, and reflects the overall azimuth state of the formation. Determining the formation occurrence is very important for determining the spatial position and structural deformation of the formation.

[0138] When the drilling operation reaches a certain distance, the shale formation structure map can be updated in time according to the latest formation depth and occurrence of the drill bit position at the drilling operation distance, so that the dynamic prediction of the formation in the un-drilled area can be realized, and the foresight of the subsequent guidance is greatly improved.

[0139] The formation abrupt change considered by the trajectory prediction unit can include formation depth abrupt change and / or formation occurrence abrupt change, and the special detailed structure can include small folds and / or small fractures in the formation.

[0140] If the subsequent horizontal well trajectory passes through the area where the formation abrupt change and / or the special detailed structure exist, the high-quality shale section target window of the horizontal well is easily deviated, which leads to poor fracturing effect of the shale gas horizontal well and no economic benefit of exploration and development.

[0141] The existing rotary steerable bit technology can only make backward correction according to the current point information, and the reaction to the formation abrupt change is slow, and the detailed structure and small fractures of the formation cannot be located, and the guidance accuracy is limited. Even if the research area structure map is used as an auxiliary, due to the complex and variable structure, the actual drilling is greatly different from the initial structure map. In the present embodiment, the shale structure map is updated in time according to the drilled part, the trajectory prediction unit can accurately dynamically predict the formation change of the un-drilled part, so that the whole guidance system can quickly react. Especially in the mining environment of complex geological conditions, the beneficial effects of the present embodiment relative to the prior art are more significant.

[0142] In the guiding design unit, if the predicted result shows that there is no mutation and / or special detailed structure in the stratum along the horizontal well trajectory within the subsequent preset drilling length, the drilling direction of the drill bit can be continued as originally designed; if the predicted result shows that there is a mutation and / or special detailed structure in the stratum along the horizontal well trajectory within the subsequent preset drilling length, the drilling direction of the drill bit can be adjusted to ensure that the horizontal section trajectory is always located in the high-quality production section, thereby improving the drilling rate of the shale gas horizontal well, reducing the cost, and improving the economic benefit.

[0143] In some embodiments, the apparatus further comprises:

[0144] a fine structure interpretation unit configured to perform fine structure interpretation using seismic data to obtain shale reservoir fault features and horizon features;

[0145] an initial velocity model establishment unit configured to establish an initial velocity model for time-depth conversion in combination with well logging curves, well logging layering, fault features, and horizon features.

[0146] The fault features of the shale reservoir fault can include:

[0147] the position and trend of the fault: confirming the position of the fault plane in space and the extension direction of the fault;

[0148] the dip of the fault: the dip angle of the fault, whether it is vertical or oblique;

[0149] the nature of the fault: whether it is a normal fault, a reverse fault, or a cross fault;

[0150] the distribution range of the fault: whether the fault penetrates the entire target horizon;

[0151] the width of the fault zone: the size of the fracture zone in the fault zone.

[0152] The horizon features of the shale reservoir fault can include:

[0153] the upper and lower boundaries of the horizon: the top and bottom boundaries of the target reservoir horizon;

[0154] the thickness of the horizon: the statistics of the overall thickness of the reservoir;

[0155] the burial depth of the horizon: determining the depth information of the reservoir;

[0156] the occurrence of the horizon: the overall tendency direction of the reservoir;

[0157] the in-layer detailed structure: small folds, small fault blocks, and other structures in the layer.

[0158] Establishing the initial velocity model for time-depth conversion can generally include the following steps:

[0159] (1) Collecting required data: well logging curves, well logging layering results, fault features, and horizon features of the study area;

[0160] (2) Correlate and compare the well logging curves to determine the correlation between the wells.

[0161] (3) On the basis of the correlation, determine the time-depth relationship of the formation boundaries.

[0162] (4) Collect or test the acoustic velocity parameters of each formation.

[0163] (5) Digitize and organize the above data and input them into a computer.

[0164] (6) Specific software can be used, such as Petrel of Schlumberger Company, Hampson-Russell of CGG Company, and Kingdom of SMT Company, to establish a velocity model for time-depth conversion.

[0165] The velocity model can include the top and bottom board time or depth, velocity parameters, and other information of each layer, and the velocity model is usually verified to ensure the consistency of the time-depth relationship of each layer.

[0166] Common algorithms for establishing a velocity model for time-depth conversion include grid method, velocity disturbance method, multi-parameter joint inversion and genetic algorithm, particle swarm algorithm, and other intelligent algorithms.

[0167] According to the data source integration of the embodiment, multi-source information such as seismic data, logging data, and geological data is organically combined, the constraint of velocity field simulation is enhanced, which is conducive to obtaining a high-quality velocity model and laying a foundation for subsequent accurate steering calculation.

[0168] In some embodiments, the while-drilling curve collecting unit, the model updating unit, the trajectory prediction unit, and the steering design unit are repeatedly called during the drilling operation.

[0169] In some embodiments, the preset drilling length ranges from 10 m to 30 m.

[0170] The shale gas horizontal well geophysical steering device provided by the embodiment solves the problem that current geological steering cannot predict the depth and occurrence of subsequent formations of a horizontal well, and the embodiment adopts dynamic adjustment to ensure high-speed drilling of a shale gas horizontal well, improves the drilling rate of high-quality shale, saves costs, provides support for high-quality exploration and development of shale gas, and is conducive to ensuring national energy security.

[0171] Other detailed descriptions and advantages of the embodiment can be referred to the corresponding descriptions in the foregoing embodiments, which will not be repeated here.

[0172] Example 4

[0173] According to another aspect of the present invention, an electronic device is provided. The electronic device includes:

[0174] Memory, which stores executable instructions:

[0175] A processor runs the executable instructions in the memory to implement the shale gas horizontal well geophysical exploration steering method according to the present invention.

[0176] The method comprises the following steps:

[0177] Step 1: Obtain an initial velocity model of the study area, and use the initial velocity model to perform time-depth conversion on fault characteristics and horizon characteristics to obtain an initial shale stratigraphic structure map;

[0178] Step 2: designing an initial drilling plan based on the initial shale formation structure map;

[0179] Step 3: Perform drilling operations and collect logging curves of the drilling. After the drilling operation distance reaches the preset drilling length, compare the collected logging curves of the drilling with the logging curves of adjacent wells to obtain the formation depth and occurrence at the drill bit position;

[0180] Step 4: adding the newly acquired formation depth and occurrence to the current velocity model to update the velocity model, and using the updated velocity model to update the current shale formation structure map;

[0181] Step 5: Based on the updated shale formation structure map, it is predicted whether there is a sudden change in the formation along the horizontal well trajectory within the subsequent preset drilling length and whether there is a special detailed structure;

[0182] Step 6: Based on the prediction, design the drill bit direction for further drilling operations.

[0183] In some embodiments, before step 1, the method further comprises establishing an initial velocity model by the following method:

[0184] Using seismic data, we conduct detailed structural interpretation to obtain the fault characteristics and stratigraphic characteristics of shale reservoirs;

[0185] The initial velocity model of time-depth conversion is established by combining well logging curves, logging layers, fault characteristics and horizon characteristics.

[0186] In some embodiments, if it is predicted that there is a sudden change and / or special detailed structure in the formation of the horizontal well trajectory within the subsequent preset drilling length, then in step 6, the drill bit direction is adjusted based on the prediction.

[0187] In some embodiments, the method further comprises:

[0188] During the drilling operation, the velocity model and the shale formation structure map are updated every preset drilling length, and it is predicted whether there is a mutation and whether there is a special detail structure in the stratum of the horizontal well trajectory in the subsequent preset drilling length based on the updated shale formation structure map, and based on the prediction, the drilling direction of the further drilling operation is designed.

[0189] In some embodiments, the preset drilling length ranges from 10m to 30m.

[0190] In some embodiments, the collected logging curves of the drilling include gamma curves, resistivity curves, sonic curves and density curves.

[0191] Specifically, the memory can include one or more computer program products, which can include various forms of computer readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may, for example, include random access memory (RAM), cache memory, and / or the like. The non-volatile memory may, for example, include read-only memory (ROM), hard disk, flash memory, and / or the like.

[0192] The processor can be a central processing unit (CPU) or other form of processing unit having data processing and / or instruction execution capabilities, and can control other components in the electronic device to perform desired functions. In one embodiment of the present application, the processor is used to run the computer readable instructions stored in the memory.

[0193] The embodiment discloses a volcanic rock porosity prediction device, and the embodiment establishes the relationship between porosity and lithofacies and conventional logging curves based on existing measured data through a LASSO algorithm, relies on measured data in a research area rather than experience parameters or core samples in a specific area in the past, the prediction process of the embodiment is less disturbed by human beings, and the lithofacies information is added in the prediction, so that the accuracy of porosity prediction in the research area can be effectively improved.

[0194] Detailed descriptions about the embodiment can refer to the corresponding descriptions in the foregoing embodiments, which will not be repeated here.

[0195] Example 5

[0196] According to another aspect of the present application, a computer readable storage medium is also provided, which stores a computer program, and the computer program is executed by a processor to implement the geophysical prospecting steering method for shale gas horizontal wells according to the present application.

[0197] The method comprises the following steps:

[0198] Step 1, obtaining an initial velocity model of a study area, and using the initial velocity model to perform time-depth conversion of fault features and horizon features to obtain an initial shale formation structure map;

[0199] Step 2, designing an initial drilling plan based on the initial shale formation structure map;

[0200] Step 3, performing drilling operations and collecting well logging curves of the drilling, and after a preset drilling length is reached, comparing the collected well logging curves of the drilling with well logging curves of a neighboring well to obtain formation depth and occurrence of a drill bit position;

[0201] Step 4, adding the newly obtained formation depth and occurrence to a current velocity model, updating the velocity model, and using the updated velocity model to update a current shale formation structure map;

[0202] Step 5, predicting whether there is a mutation and whether there is a special detailed structure in a formation along a horizontal well trajectory within a subsequent preset drilling length based on the updated shale formation structure map;

[0203] Step 6, based on the prediction, designing a drill bit direction for further drilling operations.

[0204] In some embodiments, before the step 1, the method further comprises establishing the initial velocity model by:

[0205] using seismic data to perform fine structure interpretation to obtain shale reservoir fault features and horizon features;

[0206] combining well logging curves, well logging layering, fault features and horizon features to establish an initial velocity model for time-depth conversion.

[0207] In some embodiments, if it is predicted that there is a mutation and / or there is a special detailed structure in a formation along a horizontal well trajectory within a subsequent preset drilling length, in the step 6, based on the prediction, the drill bit direction is adjusted.

[0208] In some embodiments, the method further comprises:

[0209] In the drilling operation process, the velocity model and the shale formation structure map are updated every preset drilling length, and whether there is a mutation and whether there is a special detailed structure in a formation along a horizontal well trajectory within a subsequent preset drilling length is predicted based on the updated shale formation structure map, and based on the prediction, a drill bit direction for further drilling operations is designed.

[0210] In some embodiments, the preset drilling length ranges from 10m to 30m.

[0211] In some embodiments, the collected well logging curves of the wellbore include gamma curves, resistivity curves, sonic curves, and density curves.

[0212] The embodiment discloses a volcanic rock porosity prediction device, and the embodiment establishes the relationship between porosity and lithofacies and conventional logging curves based on existing measured data through a LASSO algorithm, relies on measured data of a research area rather than experience parameters or core samples of a specific area in the past, the prediction process of the embodiment is less disturbed by human beings, and the lithofacies information is added in the prediction, so that the accuracy of porosity prediction of the research area can be effectively improved.

[0213] The computer readable storage medium according to the embodiment of the present application has non-transitory computer readable instructions stored thereon. When the non-transitory computer readable instructions are run by a processor, all or part of the steps of the method of each embodiment of the present application are executed.

[0214] The computer readable storage medium includes, but is not limited to, an optical storage medium (for example, a CD-ROM and a DVD), a magneto-optical storage medium (for example, an MO), a magnetic storage medium (for example, a magnetic tape or a mobile hard disk), a medium with a built-in rewritable non-volatile memory (for example, a memory card), and a medium with a built-in ROM (for example, a ROM cartridge).

[0215] Those skilled in the art should understand that, in order to solve the technical problem of how to obtain a good user experience effect, the embodiment can also include well-known structures such as a communication bus, an interface and the like, and these well-known structures should also be included in the protection scope of the present application.

[0216] Detailed descriptions of the embodiment can be referred to the corresponding descriptions in the foregoing embodiments, which will not be described here.

[0217] To sum up, the beneficial effects of each embodiment of the present application at least include:

[0218] (1) The shale gas horizontal well drilling rate is improved, and the horizontal section trajectory is ensured to be located in a high-quality production section.

[0219] (2) The dynamic prediction of the stratum of the un-drilled area is realized, and the foresight of the guidance is greatly improved.

[0220] (3) Multi-source information is used to enhance data constraints, so that the guidance result is more accurate and reliable.

[0221] (4) The automatic, intelligent and fine guidance process is realized, and the uncertainty caused by manual experience is reduced.

[0222] (5) The whole guidance system reacts quickly, and can realize dynamic real-time adjustment, so that the guidance efficiency is greatly improved.

[0223] (6) Reduces or avoids rework and redrill caused by deviating from the target layer, and reduces development cost;

[0224] (7) The guiding system has great flexibility, can adapt to complex geological conditions, and reduces the dependence on geological prediction;

[0225] (8) It is conducive to efficient development of shale gas, improves single well production, and reduces comprehensive development cost;

[0226] (9) The application of the guiding technology is conducive to promoting the rapid development of shale gas industry;

[0227] (10) It has important significance for ensuring energy security and promoting unconventional oil and gas revolution.

[0228] The above has described the embodiments of the present application, the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles, practical application or technical improvement of the technology in the market of the embodiments, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein.

Claims

1. A shale gas horizontal well geophysical guidance method, characterized in that: The method comprises: Step 1: Obtain an initial velocity model of the study area, and use the initial velocity model to perform time-depth conversion on fault characteristics and horizon characteristics to obtain an initial shale stratigraphic structure map; Step 2: designing an initial drilling plan based on the initial shale formation structure map; Step 3: Perform drilling operations and collect logging curves of the drilling. After the drilling operation distance reaches the preset drilling length, compare the collected logging curves of the drilling with the logging curves of adjacent wells to obtain the formation depth and occurrence at the drill bit position; Step 4: adding the newly acquired formation depth and occurrence to the current velocity model to update the velocity model, and using the updated velocity model to update the current shale formation structure map; Step 5: Based on the updated shale formation structure map, it is predicted whether there is a sudden change in the formation along the horizontal well trajectory within the subsequent preset drilling length and whether there is a special detailed structure; Step 6: Based on the prediction, design the drill bit direction for further drilling operations. If it is predicted that there will be a sudden change and / or special detailed structure in the horizontal well trajectory formation within the subsequent preset drilling length, adjust the drill bit direction based on the prediction.

2. The method according to claim 1, characterized in that Before step 1, the method further includes establishing an initial velocity model by the following method: Using seismic data, we conduct detailed structural interpretation to obtain the fault characteristics and stratigraphic characteristics of shale reservoirs; The initial velocity model of time-depth conversion is established by combining well logging curves, logging layers, fault characteristics and horizon characteristics.

3. The method according to claim 1, characterized in that The method further comprises: During the drilling operation, the velocity model and shale formation structure map are updated every preset drilling length, and based on the updated shale formation structure map, it is predicted whether there are sudden changes in the horizontal well trajectory formation and whether there are special detailed structures within the subsequent preset drilling length. Based on the prediction, the drill bit direction for further drilling operations is designed.

4. The method according to any one of claims 1 to 3, characterized in that The preset drilling length ranges from 10m to 30m.

5. The method according to claim 1, wherein The collected well logging curves include gamma curves, resistivity curves, acoustic wave curves and density curves.

6. A shale gas horizontal well geophysical exploration guidance device, characterized in that: The device comprises: The initial model acquisition unit is used to obtain the initial velocity model of the study area, and use the initial velocity model to perform time-depth conversion on the fault characteristics and horizon characteristics to obtain the initial shale formation structure map; An initial plan design unit, used to design an initial drilling plan based on an initial shale formation structure map; The drilling curve collection unit is used to perform drilling operations and collect drilling logging curves. After the drilling operation distance reaches the preset drilling distance, the collected drilling logging curves are compared with the logging curves of adjacent wells to obtain the formation depth and occurrence at the drill bit position; A model updating unit is used to add the newly acquired formation depth and occurrence to the current velocity model, update the velocity model, and update the current shale formation structure map using the updated velocity model; A trajectory prediction unit is used to predict whether there are sudden changes in the strata along the horizontal well trajectory within the preset drilling length and whether there are special detailed structures based on the updated shale formation structure map; The guidance design unit is used to design the drill bit direction for further drilling operations based on the prediction. If it is predicted that there will be a sudden change and / or special detailed structure in the horizontal well trajectory formation within the subsequent preset drilling length, the guidance design unit will adjust the drill bit direction based on the prediction.

7. The device according to claim 6, characterized in that The device further comprises: Fine structural interpretation unit, used to perform fine structural interpretation using seismic data to obtain shale storage fault characteristics and stratigraphic characteristics; The initial velocity model establishment unit is used to establish an initial velocity model for time-depth conversion by combining well logging curves, well logging layers, fault characteristics and horizon characteristics.

8. An electronic device, characterized in that: The electronic device comprises: Memory, which stores executable instructions: A processor, wherein the processor runs the executable instructions in the memory to implement the method according to any one of claims 1 to 5.

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