Logging depth correction method and system and computer readable storage medium

Abstract

The invention discloses a logging depth correction method and system and a computer readable storage medium, and the method comprises the following steps: determining a reference well and at least one correction well needing depth correction in a plurality of wells under the same oil field pressure system; establishing a reference well pressure trend model according to the measurement data of the reference well; establishing a corrected well pressure trend model according to the measured data of the corrected well; according to the reference well pressure trend model and the correction well pressure trend model, a depth correction value is obtained through analysis; and correcting the measured depth value of the correction well according to the depth correction value. According to the method, the precision of depth measurement can be improved, the precision of oil and gas reservoir evaluation is further improved, and the method is high in operability.

Description

Technical Field

[0001] The present invention relates to the field of well logging technology, and in particular to a well logging depth correction method, system and computer-readable storage medium. Background Art

[0002] Depth is the most fundamental well logging parameter. Other parameters are scaled with depth and are directly related to the evaluation and development of mineral resources. Depth is typically measured by recording the length of the cable or drill pipe. Due to factors such as the cable's deadweight, friction, and buoyancy, the cable or drill pipe may be compressed or stretched. This leads to uncertainty in the depth measurement and calibration of a single well, resulting in a mismatch between the measured depth and the actual depth. Furthermore, depth errors accumulate as the drilling trajectory lengthens.

[0003] In the field of oil and gas, depth data is important for oil and gas reservoir evaluation and exploitation. Since there are errors in the measured depth of a single well, the measured depths of multiple wells will not match the actual depths. It is necessary to analyze the measurement data of multiple wells and correct the depth of each well to ensure that the comparison and interpretation of stratigraphic information from different wells are more accurate.

[0004] Current depth correction methods primarily focus on single-well cable stretch correction, velocity correction, and relative depth correction. Inter-well correction utilizes information such as the oil-water interface encountered during drilling to level the depth. This method has low accuracy and can only be applied to wells where an oil-water interface is encountered. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a logging depth correction method, system and computer-readable storage medium for at least one defect of the related technology mentioned in the above background technology: the measured depth of multiple wells does not match the actual depth.

[0006] The technical solution adopted by the present invention to solve the technical problem is to construct a well logging depth correction method, which includes the following steps:

[0007] Among multiple wells under the same oilfield pressure system, determine a reference well and at least one correction well that requires depth correction;

[0008] Based on the measurement data of the benchmark well, a benchmark well pressure trend model is established;

[0009] Based on the measurement data of the calibration well, a pressure trend model of the calibration well is established;

[0010] According to the pressure trend model of the reference well and the pressure trend model of the correction well, the depth correction value is obtained by analysis;

[0011] The measured depth value of the calibration well is corrected according to the depth correction value.

[0012] In some embodiments, the reference well is a vertical well and the calibration well is a directional well.

[0013] In some embodiments, the oilfield pressure system is a pressure system of oil and water layers in the oilfield.

[0014] In some embodiments, the measurement data of the reference well and the measurement data of the calibration well are respectively measurement data of the water layer of the oil field.

[0015] In some embodiments, the measurement data is cable or while-drilling pressure profile measurement data, and the measurement data includes pressure data and depth data.

[0016] In some embodiments, the reference well pressure trend model is a reference well pressure trend line established based on pressure values ​​and depth values ​​of at least two reference well pressure measurement points;

[0017] The calibration well pressure trend model is a calibration well pressure trend line established based on the pressure values ​​and depth values ​​of at least two calibration well pressure measurement points.

[0018] In some embodiments, analyzing and obtaining a depth correction value based on the reference well pressure trend model and the correction well pressure trend model includes:

[0019] With the reference well pressure trend model as a reference, the correction well pressure trend model is moved toward the reference well pressure trend model so that the two coincide with each other. The distance moved is the depth correction value.

[0020] In some embodiments, correcting the measured depth value of the calibration well according to the depth correction value includes:

[0021] Add the measured depth value of the calibration well to the depth correction value to obtain the corrected measured depth value.

[0022] The present invention also constructs a well logging depth correction system, comprising:

[0023] A determination module is used to determine a reference well and at least one correction well requiring depth correction among multiple wells under the same oilfield pressure system;

[0024] A benchmark establishment module is used to establish a benchmark well pressure trend model based on the measurement data of the benchmark well;

[0025] A calibration establishment module is used to establish a calibration well pressure trend model based on the measurement data of the calibration well;

[0026] An analysis module, configured to obtain a depth correction value based on a reference well pressure trend model and a correction well pressure trend model; and

[0027] The correction module is used to correct the measured depth value of the correction well according to the depth correction value.

[0028] The present invention also constructs a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the well logging depth correction method as described in any one of the above items is implemented.

[0029] By implementing the present invention, the following beneficial effects are achieved:

[0030] The present invention proposes a well logging depth correction method, which measures pressure data in a reference well and a correction well, and uses the pressure data to correct the measured depth value of the correction well to within the same reference depth framework, thereby achieving the purpose of well logging depth correction, thereby improving the accuracy of depth measurement, and further improving the accuracy of oil and gas reservoir evaluation, and the method is highly operational. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0032] Figure 1 A flow chart showing an embodiment of a method for correcting well logging depth according to the present invention is shown;

[0033] Figure 2 A schematic diagram showing an embodiment of a reference well pressure trend model and a calibration well pressure trend model according to the present invention;

[0034] Figure 3 The figure shows a logic block diagram of an embodiment of the well logging depth correction system of the present invention. DETAILED DESCRIPTION

[0035] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0036] It should be noted that the flowcharts shown in the accompanying drawings are for illustrative purposes only and do not necessarily include all content and operations / steps, nor must they be executed in the order described. For example, some operations / steps may be decomposed, while others may be combined or partially combined. Therefore, the actual execution order may vary depending on the actual situation.

[0037] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically separate entities. That is, these functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0038] like Figure 1 As shown, some embodiments of the present invention disclose a method for correcting well logging depth, the method comprising the following steps:

[0039] Among multiple wells under the same oilfield pressure system, a reference well and at least one calibration well requiring depth calibration are determined. It is understandable that the at least one well may be one, two, three, or any number of wells.

[0040] Based on the measurement data of the benchmark well, a benchmark well pressure trend model is established;

[0041] Based on the measurement data of the calibration well, a pressure trend model of the calibration well is established;

[0042] According to the pressure trend model of the reference well and the pressure trend model of the correction well, the depth correction value is obtained by analysis;

[0043] The measured depth value of the calibration well is corrected according to the depth correction value.

[0044] This embodiment proposes a well logging depth correction method, which measures pressure data in a reference well and a correction well, and uses the pressure data to correct the measured depth value of the correction well to within the same reference depth framework, thereby achieving the purpose of well logging depth correction, thereby improving the accuracy of depth measurement, and further improving the accuracy of oil and gas reservoir evaluation. The method is also highly operational.

[0045] The underground pressure system within the oil field is stable. Within the same pressure system, the correspondence between pressure and depth is fixed. If the depth is consistent, the pressure is consistent. Therefore, the reference well and the calibration well must be compared under the same oil field pressure system. If they are not under the same pressure system, they cannot be compared.

[0046] In some embodiments, the reference well is a vertical well, and the calibration well is a directional well. A vertical well is a well drilled along a vertical line (theoretically, the well inclination is zero) to reach the target layer. A directional well is a well drilled along a non-vertical line to reach the target layer, including cluster wells.

[0047] In some embodiments, the oil field pressure system is a pressure system of oil layers and water layers in the oil field. The pressure system refers to the distribution of formation pressure (also called formation pore pressure). The formation is an underground rock layer. Some rocks have pores and are permeable, which is the reservoir. If there is water in the reservoir, it is the water layer, and if there is oil, it is the oil layer. Therefore, the permeability of the oil layer and the water layer can measure the formation pressure. The formation pressure is the pressure of the fluid in the formation pores. The fluid includes oil, gas and water. Generally, the normal formation pressure is equal to the hydrostatic pressure of the formation fluid. Its value is equal to the hydrostatic pressure of the continuous formation water from the ground to a certain depth underground, and is generally linearly related to the fluid density. Pressure is actually pressure intensity, for example, hydrostatic pressure = fluid density × gravitational acceleration × depth. In the same pressure system, the pressure increases with increasing depth. When the fluid density remains unchanged, the slope is also unchanged, such as Figure 2 Different pressure systems may have isolation, which will affect the pressure value and slope, so they must be under the same oil field pressure system.

[0048] In some embodiments, in order to eliminate the buoyancy effect caused by the difference in oil and gas density, the measurement data of the reference well and the measurement data of the calibration well are respectively the measurement data of the oilfield water layer, that is, the measurement points of the reference well and the calibration well are preferably located in the water layer.

[0049] In some embodiments, the measurement data of the reference well and the calibration well is wireline or while-drilling pressure profile measurement data, including pressure and depth data at the measurement point. For example, the measurement data can be collected using a wireline formation tester (MDT) or a repetitive formation tester (RFT). The wireline formation tester (MDT) and repetitive formation tester (RFT) are examples only and are not intended to limit this application; other methods are also possible.

[0050] In some embodiments, such as Figure 2 As shown, the reference well pressure trend model is a reference well pressure trend line 4 established based on the pressure and depth values ​​of at least two reference well pressure measurement points 3, and the calibration well pressure trend model is a calibration well pressure trend line 6 established based on the pressure and depth values ​​of at least two calibration well pressure measurement points 5. It will be understood that the at least two measurement points can be two, three, or any other number, and a greater number of measurement points results in more accurate depth calibration.

[0051] Among them, a depth longitudinal coordinate axis 1 and a pressure transverse coordinate axis 2 can be established, or a pressure longitudinal coordinate axis and a depth transverse coordinate axis can be established, so as to generate a pressure trend line based on the pressure value and depth value of the measuring point. In some embodiments, the reference well pressure trend line 4 and the correction well pressure trend line 6 are straight lines with fixed slopes.

[0052] In some embodiments, analyzing and obtaining a depth correction value based on the reference well pressure trend model and the correction well pressure trend model includes:

[0053] like Figure 2 As shown, with the reference well pressure trend model as a reference, the correction well pressure trend model is moved toward the reference well pressure trend model (specifically, moved up and down) so that the two overlap. The moving distance 7 is the depth correction value, which can be positive or negative.

[0054] In some embodiments, correcting the measured depth value of the calibration well according to the depth correction value includes: adding the depth correction value to the measured depth value of the calibration well to obtain a corrected measured depth value.

[0055] like Figure 3 As shown, some embodiments of the present invention disclose a well logging depth correction system, comprising:

[0056] A determination module is used to determine a reference well and at least one correction well requiring depth correction among multiple wells under the same oilfield pressure system;

[0057] A benchmark establishment module is used to establish a benchmark well pressure trend model based on the measurement data of the benchmark well;

[0058] A calibration establishment module is used to establish a calibration well pressure trend model based on the measurement data of the calibration well;

[0059] An analysis module, configured to obtain a depth correction value based on a reference well pressure trend model and a correction well pressure trend model; and

[0060] The correction module is used to correct the measured depth value of the correction well according to the depth correction value.

[0061] This embodiment proposes a well logging depth correction system, which measures pressure data in a reference well and a correction well, and uses the pressure data to correct the measured depth value of the correction well to within the same reference depth framework, thereby achieving the purpose of well logging depth correction, thereby improving the accuracy of depth measurement and further improving the accuracy of oil and gas reservoir evaluation. The method is also highly operational.

[0062] The underground pressure system within the oil field is stable. Within the same pressure system, the correspondence between pressure and depth is fixed. If the depth is consistent, the pressure is consistent. Therefore, the reference well and the calibration well must be compared under the same oil field pressure system. If they are not under the same pressure system, they cannot be compared.

[0063] In some embodiments, the reference well is a vertical well, and the calibration well is a directional well. A vertical well is a well drilled along a vertical line (theoretically, the well inclination is zero) to reach the target layer. A directional well is a well drilled along a non-vertical line to reach the target layer, including cluster wells.

[0064] In some embodiments, the oil field pressure system is a pressure system of oil layers and water layers in the oil field. The pressure system refers to the distribution of formation pressure (also called formation pore pressure). The formation is an underground rock layer. Some rocks have pores and are permeable, which is the reservoir. If there is water in the reservoir, it is the water layer, and if there is oil, it is the oil layer. Therefore, the permeability of the oil layer and the water layer can measure the formation pressure. The formation pressure is the pressure of the fluid in the formation pores. The fluid includes oil, gas and water. Generally, the normal formation pressure is equal to the hydrostatic pressure of the formation fluid. Its value is equal to the hydrostatic pressure of the continuous formation water from the ground to a certain depth underground, and is generally linearly related to the fluid density. Pressure is actually pressure intensity, for example, hydrostatic pressure = fluid density × gravitational acceleration × depth. In the same pressure system, the pressure increases with increasing depth. When the fluid density remains unchanged, the slope is also unchanged, such as Figure 2Different pressure systems may have isolation, which will affect the pressure value and slope, so they must be under the same oil field pressure system.

[0065] In some embodiments, in order to eliminate the buoyancy effect caused by the difference in oil and gas density, the measurement data of the reference well and the measurement data of the calibration well are respectively the measurement data of the oilfield water layer, that is, the measurement points of the reference well and the calibration well are preferably located in the water layer.

[0066] In some embodiments, the measurement data of the reference well and the calibration well is wireline or while-drilling pressure profile measurement data, including pressure and depth data at the measurement point. For example, the measurement data can be collected using a wireline formation tester (MDT) or a repetitive formation tester (RFT). The wireline formation tester (MDT) and repetitive formation tester (RFT) are examples only and are not intended to limit this application; other methods are also possible.

[0067] In some embodiments, such as Figure 2 As shown, the reference well pressure trend model is a reference well pressure trend line 4 established based on the pressure and depth values ​​of at least two reference well pressure measurement points 3, and the calibration well pressure trend model is a calibration well pressure trend line 6 established based on the pressure and depth values ​​of at least two calibration well pressure measurement points 5. It will be understood that the at least two measurement points can be two, three, or any other number, and a greater number of measurement points results in more accurate depth calibration.

[0068] Among them, a depth longitudinal coordinate axis 1 and a pressure transverse coordinate axis 2 can be established, or a pressure longitudinal coordinate axis and a depth transverse coordinate axis can be established, so as to generate a pressure trend line based on the pressure value and depth value of the measuring point. In some embodiments, the reference well pressure trend line 4 and the correction well pressure trend line 6 are straight lines with fixed slopes.

[0069] In some embodiments, analyzing and obtaining a depth correction value based on the reference well pressure trend model and the correction well pressure trend model includes:

[0070] like Figure 2 As shown, with the reference well pressure trend model as a reference, the correction well pressure trend model is moved toward the reference well pressure trend model (specifically, moved up and down) so that the two overlap. The moving distance 7 is the depth correction value, which can be positive or negative.

[0071] In some embodiments, correcting the measured depth value of the calibration well according to the depth correction value includes: adding the depth correction value to the measured depth value of the calibration well to obtain a corrected measured depth value.

[0072] Some embodiments of the present invention disclose a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for correcting the well logging depth as described in any of the above embodiments is implemented, which will not be described in detail here.

[0073] In one specific example, Oilfield X contains 26 reservoirs, including 17 bottom-water reservoirs and 9 edge-water reservoirs. Sedimentation primarily originates from the ancient Pearl River. The oilfield develops delta plain to delta front deposits, including distributary channels, underwater distributary channels, and estuary bars. Buried at depths of 2482.9 to 3401.0 meters, well logging interpretation indicates a porosity distribution of 12.3% to 26.8% and a permeability of 2.2 to 1280.4 mD, generally classifying the reservoir as medium-porosity and medium-permeability. Calculated pressure data indicate a formation pressure gradient of 0.988 MPa / 100 m, indicating the reservoir is within a normal pressure regime.

[0074] Oilfield X has two wells, A and B. Well A is a vertical exploratory well, while Well B is a directional appraisal well. The two wells are approximately 1200 meters apart. The measured depths of the two wells do not match the actual depths, indicating differences between the oil and water zones. Both wells have pressure data measured using a wireline formation testing tool (MDT). Because Well A is the discovery well and has comprehensive data, it was selected as the reference well. The MDT pressure gradients of the water zones in Wells A and B are consistent and stable. When the pressure and depth data from the two wells are projected into the same coordinate system, a consistent difference in the pressure trend lines is observed. This difference is due to systematic depth errors. By correcting the pressure measurement points of Well B downward, the pressure trend line of Well B coincides with that of Well A. After applying the logging depth correction method based on pressure data to Well B, the oil and water zone data for the two wells are essentially consistent.

[0075] It should be noted that the numerical values ​​listed in this specific embodiment are only examples and are not intended to limit the present application. Other values ​​are also possible.

[0076] It is understandable that the above embodiments only express some implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, the above embodiments or technical features can be freely combined, and several deformations and improvements can be made, which all fall within the scope of protection of the present invention, that is, the embodiments described in "some embodiments" can be freely combined with any of the above and below embodiments. Therefore, all equivalent transformations and modifications made to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A method for correcting well logging depth, characterized in that: The method comprises the following steps: Among multiple wells under the same oilfield pressure system, determine a reference well and at least one correction well that requires depth correction; Based on the measurement data of the benchmark well, a benchmark well pressure trend model is established; Based on the measurement data of the calibration well, a pressure trend model of the calibration well is established; According to the pressure trend model of the reference well and the pressure trend model of the correction well, the depth correction value is obtained by analysis; The measured depth value of the calibration well is corrected according to the depth correction value.

2. The method for correcting well logging depth according to claim 1, wherein: The reference well is a vertical well, and the calibration well is a directional well.

3. The method for correcting well logging depth according to claim 1, wherein: The oil field pressure system is the pressure system of the oil and water layers in the oil field.

4. The method for correcting well logging depth according to claim 3, characterized in that: The measurement data of the reference well and the measurement data of the calibration well are respectively the measurement data of the oilfield water layer.

5. The well logging depth correction method according to claim 1, characterized in that: The measurement data is cable or while-drilling pressure profile measurement data, and the measurement data includes pressure data and depth data.

6. The method for correcting well logging depth according to claim 1, wherein: The reference well pressure trend model is a reference well pressure trend line established based on the pressure values ​​and depth values ​​of at least two reference well pressure measurement points; The calibration well pressure trend model is a calibration well pressure trend line established based on the pressure values ​​and depth values ​​of at least two calibration well pressure measurement points.

7. The method for correcting well logging depth according to claim 1, wherein: According to the pressure trend model of the reference well and the pressure trend model of the correction well, the depth correction value is obtained by analysis, including: With the reference well pressure trend model as a reference, the correction well pressure trend model is moved toward the reference well pressure trend model so that the two coincide with each other. The distance moved is the depth correction value.

8. The method for correcting well logging depth according to claim 1, wherein: Correct the measured depth value of the calibration well according to the depth correction value, including: Add the measured depth value of the calibration well to the depth correction value to obtain the corrected measured depth value.

9. A well logging depth correction system, characterized in that: include: A determination module is used to determine a reference well and at least one correction well requiring depth correction among multiple wells under the same oilfield pressure system; A benchmark establishment module is used to establish a benchmark well pressure trend model based on the measurement data of the benchmark well; A calibration establishment module is used to establish a calibration well pressure trend model based on the measurement data of the calibration well; An analysis module, configured to obtain a depth correction value based on a reference well pressure trend model and a correction well pressure trend model; as well as, The correction module is used to correct the measured depth value of the correction well according to the depth correction value.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the well logging depth correction method according to any one of claims 1 to 8 is implemented.

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