A method, system, apparatus, and medium for obtaining wellbore fluid density

Abstract

This invention provides a method, system, apparatus, and medium for obtaining wellbore fluid density, comprising the following steps: acquiring burst peak count rate curves from neutron lifetime logging capture time spectrum data and obtaining burst peak decay rates; constructing a calibration relationship between wellbore fluid density data obtained from production profile logging and burst peak decay rates to obtain a conversion relationship between burst peak decay rates and fluid density; obtaining a wellbore fluid density curve based on the conversion relationship between burst peak decay rates and fluid density; this application, by mining capture time spectrum information and extracting feature values ​​from neutron lifetime logging capture spectrum data, constructs a relationship between neutron lifetime logging and fluid density, thereby achieving the purpose of quantitatively evaluating fluid density within the wellbore; it opens up new application areas for neutron lifetime logging data, obtains key parameters that could previously only be obtained through production profile logging, and provides technical support for dynamic research on oil and gas reservoirs.

Description

Technical Field

[0001] This invention relates to the field of production logging in geophysical logging, specifically to a method, system, equipment, and medium for obtaining wellbore fluid density. Background Technology

[0002] Fluid density data within the wellbore can indicate the properties of the fluid within the wellbore, the properties of the fluid produced from the main producing layers, and the location of the fluid accumulation surface in the wellbore. This is crucial for evaluating the production status of oil and gas wells. It is generally obtained through production profile logging, and the specific instruments used include radiometric density meters, tuning fork density meters, and differential pressure density meters.

[0003] Neutron lifetime logging is an important series of production logging technologies. It evaluates the remaining oil saturation of a reservoir by measuring information such as the capture cross section. With the development of technology, neutron lifetime logging has been upgraded to the full-spectrum saturation logging series, including PNST from Daqing Testing, PSSL from Xi'an Aohua, and PNX from abroad. In addition to recording the capture time spectrum, it can also record the capture energy spectrum, inelastic time spectrum, and inelastic energy spectrum, and has the ability to evaluate reservoir lithology, physical properties, and mineral composition. The near and far count rates of neutron lifetime logging are related to the production of the neutron tube, the reservoir's ability to capture thermal neutrons, the sensitivity of the detector, and also closely related to the fluid properties in the wellbore. Different fluid properties in the wellbore result in different near and far count rate values.

[0004] In existing technologies, the process of obtaining key parameters for fluid density in wellbore through production profile logging is complex and costly. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a method, system, device, and medium for obtaining wellbore fluid density, which can simply and accurately obtain the fluid density inside the wellbore, expands the application field of neutron lifetime logging data, and provides technical support for the dynamic study of oil and gas reservoirs.

[0006] This invention is achieved through the following technical solution:

[0007] A method for obtaining wellbore fluid density includes the following steps:

[0008] The burst peak count rate curve was acquired from the neutron lifetime logging capture time spectrum data, and the burst peak decay rate was obtained.

[0009] Based on the wellbore fluid density data obtained from the production profile logging and the burst peak decay rate, a calibration relationship is constructed to obtain the conversion relationship between the burst peak decay rate and fluid density.

[0010] The wellbore fluid density curve is obtained based on the relationship between the burst peak decay rate and the fluid density conversion.

[0011] Furthermore, the process of acquiring the burst peak count rate curve from the neutron lifetime logging capture time spectrum data is as follows:

[0012] Within a preset range of neutron lifetime logging capture time spectrum data, burst peaks within the preset range are obtained. The burst peaks are the highest count rates, and the burst peak count rates are obtained by sorting.

[0013] Furthermore, the process for obtaining the burst peak decay rate is as follows:

[0014] Within the preset range of neutron lifetime logging capture time spectrum data, the capture time spectrum data of near and far probes are processed to obtain the burst peak count rate curve of near and far probes. The curve value is the burst peak value of near and far probes.

[0015] The burst peak attenuation rate was obtained based on the burst peak value of the far probe and the burst peak value of the near probe.

[0016] Furthermore, the process of obtaining the burst peak attenuation rate based on the burst peak value of the far-probe and the burst peak value of the near-probe is as follows:

[0017] DENF=(MAXN-MAXF) / MAXN*100%;

[0018] Where DENF is the burst peak decay rate, MAXN is the near-probe burst peak, and MAXF is the far-probe burst peak.

[0019] Furthermore, if the burst peak attenuation rate has curve spikes that affect the clarity of the curve, a filtering method is used to remove the curve spikes.

[0020] Furthermore, the process of establishing a calibration relationship between the wellbore fluid density data obtained from the production profile logging and the burst peak decay rate, and obtaining the conversion relationship between the burst peak decay rate and fluid density, is as follows:

[0021] Based on the production profile and neutron lifetime logging information simultaneously recorded from some wells, a calibration relationship is constructed using the fluid density data obtained from the production profile logging and the burst peak decay rate:

[0022] FDENNFC = A * DENF + B;

[0023] In the formula: FDENNFC is the wellbore fluid density curve; FDEN is the fluid density; A is the multiplication coefficient; B is the addition coefficient.

[0024] Furthermore, the process of obtaining the wellbore fluid density curve based on the conversion relationship between the burst peak decay rate and fluid density is as follows:

[0025] The FDENNFC wellbore fluid density curve is used as the wellbore fluid density curve to indicate the location of fluid accumulation in the wellbore.

[0026] A system for obtaining wellbore fluid density includes:

[0027] The acquisition module is used to acquire the burst peak count rate curve from the neutron lifetime logging capture time spectrum data and obtain the burst peak decay rate.

[0028] The conversion module is used to construct a calibration relationship between wellbore fluid density data obtained from production profile logging and burst peak decay rate, and obtain the conversion relationship between burst peak decay rate and fluid density.

[0029] The output module is used to obtain the wellbore fluid density curve based on the conversion relationship between the burst peak decay rate and fluid density.

[0030] A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the steps of a method for obtaining wellbore fluid density.

[0031] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of a method for obtaining wellbore fluid density.

[0032] Compared with the prior art, the present invention has the following beneficial technical effects:

[0033] This invention provides a method, system, apparatus, and medium for obtaining wellbore fluid density, comprising the following steps: acquiring burst peak count rate curves from neutron lifetime logging capture time spectrum data and obtaining burst peak decay rates; constructing a calibration relationship between wellbore fluid density data obtained from production profile logging and burst peak decay rates to obtain a conversion relationship between burst peak decay rates and fluid density; obtaining a wellbore fluid density curve based on the conversion relationship between burst peak decay rates and fluid density; this application, by mining capture time spectrum information and extracting feature values ​​from neutron lifetime logging capture spectrum data, constructs a relationship between neutron lifetime logging and fluid density, thereby achieving the purpose of quantitatively evaluating fluid density within the wellbore; it opens up new application areas for neutron lifetime logging data, obtains key parameters that could previously only be obtained through production profile logging, and provides technical support for dynamic research on oil and gas reservoirs. Attached Figure Description

[0034] Figure 1 This is a flowchart illustrating a method for obtaining wellbore fluid density according to an embodiment of the present invention;

[0035] Figure 2 This is a diagram of the neutron lifetime logging capture time spectrum data structure in an embodiment of the present invention;

[0036] Figure 3This is a graph showing the relationship between the attenuation rate of block K and the fluid density in an embodiment of the present invention.

[0037] Figure 4 This is a curve showing the calculated fluid density based on neutron lifetime data from well K11 in this embodiment of the invention. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0039] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0040] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0041] This invention provides a method for obtaining wellbore fluid density, such as... Figure 1 As shown, it includes the following steps:

[0042] The burst peak count rate curve was acquired from the neutron lifetime logging capture time spectrum data, and the burst peak decay rate was obtained.

[0043] Based on the wellbore fluid density data obtained from the production profile logging and the burst peak decay rate, a calibration relationship is constructed to obtain the conversion relationship between the burst peak decay rate and fluid density.

[0044] The wellbore fluid density curve is obtained based on the relationship between the burst peak decay rate and the fluid density conversion.

[0045] It should be noted that the wellbore fluid density curve mentioned in this application usually refers to the fluid density curve inside the wellbore during the oil and gas development process; during the production process, the fluid density inside the wellbore changes because the fluid produced in the formation is unpredictable.

[0046] In the production process of oil and gas wells, the wellbore fluid density curve is an important reference because it can help those skilled in the art to assess the production capacity and production properties of different perforated layers, determine the water flooding situation of the well, and thus guide the adjustment of the single-well production system, extend the stable production time of the single well, and improve the recovery rate of the oil and gas reservoir.

[0047] The wellbore fluid density curve described in this application can also refer to the curve used in oil and gas engineering to represent the relationship between fluid density and depth in a wellbore. The wellbore fluid density curve can help those skilled in the art to assess and predict problems that may be encountered during drilling, such as pressure and gas intrusion, thereby helping them to better control the drilling process and ensure safe and efficient drilling operations.

[0048] Preferably, the process of acquiring the burst peak count rate curve from the neutron lifetime logging capture time spectrum data is as follows:

[0049] Within a preset range of neutron lifetime logging capture time spectrum data, burst peaks within the preset range are obtained. The burst peaks are the highest count rates, and the burst peak count rates are obtained by sorting.

[0050] It should be noted that the burst peak described in this application usually describes the characteristics of a neutron tube burst in radioactive logging. During the process of a neutron tube emitting fast neutrons, the near and far probes record the radioactive count rate that changes over time, which is generally called the time spectrum. The horizontal axis is time, and the vertical axis is the count rate. The highest value on the vertical axis is generally called the burst peak. The count rate of the burst peak of the near and far probes is called the near and far probe burst peak count rate.

[0051] Preferably, the process for obtaining the burst peak decay rate is as follows:

[0052] Within the preset range of neutron lifetime logging capture time spectrum data, the capture time spectrum data of near and far probes are processed to obtain the burst peak count rate curve of near and far probes. The curve value is the burst peak value of near and far probes.

[0053] The burst peak attenuation rate was obtained based on the burst peak value of the far probe and the burst peak value of the near probe.

[0054] Specifically, the process of obtaining the burst peak decay rate is as follows:

[0055] DENF=(MAXN-MAXF) / MAXN*100%;

[0056] Where DENF is the burst peak decay rate, MAXN is the near-probe burst peak, and MAXF is the far-probe burst peak.

[0057] Preferably, if the burst peak attenuation rate has curve spikes that affect the clarity of the curve, a filtering method is used to remove the curve spikes.

[0058] It should be noted that the process of filtering to remove curve spikes is as follows:

[0059] First choice of filter: Choose a suitable filter, such as a smoothing filter or a Gaussian filter. Filters can eliminate high-frequency noise and have a good effect on removing glitches.

[0060] Applying filters: The selected filters are applied to the curve data with spikes. The specific method is to use the discretized form of the filter function, such as convolution, to process the curve data.

[0061] Adjusting parameters: The parameters of the filter can be adjusted according to actual needs, and different parameter settings will affect the filtering effect;

[0062] Check the filtering effect: After filtering, check whether the glitches have been successfully removed. If the effect is not ideal, you may need to select or adjust the filter and adjust the parameters.

[0063] It is important to note that when using filters for de-glitching, care should be taken not to over-smooth the data, otherwise the shape of the original data may be altered. In this embodiment, appropriate filtering should be performed.

[0064] Preferably, the process of establishing a calibration relationship between the wellbore fluid density data obtained from the production profile logging and the burst peak decay rate, and obtaining the conversion relationship between the burst peak decay rate and fluid density, is as follows:

[0065] Based on the production profile and neutron lifetime logging information simultaneously recorded from some wells, a calibration relationship is constructed using the fluid density data obtained from the production profile logging and the burst peak decay rate:

[0066] FDENNFC = A * DENF + B;

[0067] In the formula: FDENNFC is the wellbore fluid density curve; FDEN is the fluid density; A is the multiplication coefficient; B is the addition coefficient.

[0068] Preferably, the process of obtaining the wellbore fluid density curve based on the conversion relationship between the burst peak decay rate and fluid density is as follows:

[0069] The FDENNFC wellbore fluid density curve is used as the wellbore fluid density curve to indicate the location of fluid accumulation in the wellbore.

[0070] Example 1:

[0071] Step 101: Extract the burst peak count rate curve:

[0072] Open the neutron lifetime logging capture time spectrum data, such as Figure 2 The image shows the structure of neutron lifetime logging capture time spectrum data. TIME represents the time interval, MCS1 represents the near-source distance count rate, and the count rate is highest in the 10th time interval, which is the burst peak. The preset range is the first 20 data intervals. Figure 2 A distinct burst peak can be observed, representing the highest count rate. Given the range of the first 20 channels, the burst peak count rate can be easily obtained using mathematical algorithms such as the "sorting method". By processing the capture time spectrum data of the far and near probes, burst peak count rate curves of the far and near probes can be obtained, which are named the far probe burst peak value MAXF and the near probe burst peak value MAXN, respectively.

[0073] Step 102: Calculate the burst peak decay rate:

[0074] DENF=(MAXN-MAXF) / MAXN*100%

[0075] Where: DENF is the burst peak decay rate (%); MAXN is the near-probe burst peak; MAXF is the far-probe burst peak.

[0076] Because neutron lifetime logging involves radioactivity, statistical fluctuations are observed. Figure 4 The DENF curve in the "peak attenuation rate" channel has many spikes, which is normal and can be filtered appropriately.

[0077] Step 103: Determine the relationship between attenuation rate and fluid density:

[0078] Some wells simultaneously recorded production profiles and neutron lifetime logs within one to two days. A calibration relationship was established using fluid density data obtained from the production profile logs and the burst peak decay rate, such as... Figure 3 The figure shows the relationship between the decay rate and fluid density in block K. The data comes from well K7. The production profile and neutron lifetime logging of this well were measured over two days in 2021.

[0079] The relationship between fluid density data and peak decay rate is generally linear, expressed as:

[0080] FDENNFC = A * DENF + B;

[0081] In the formula: FDEN is the fluid density; A is the multiplication coefficient; B is the addition coefficient;

[0082] It should be noted that for the same oil and gas reservoir, the tubing size, formation water salinity, and oil and gas properties are basically the same, so A and B are generally interchangeable. However, for different oil and gas reservoirs, it is necessary to reconstruct the scale relationship.

[0083] Step 104: Calculate the fluid density in the wellbore:

[0084] Using the calibration relationship constructed in step 103, the wellbore fluid density curve can be obtained, such as... Figure 4 The FDENNFC curve in the "Fluid Density Channel" is the wellbore fluid density curve, which can clearly reflect the location of the accumulated fluid in the wellbore.

[0085] like Figure 4 As shown, the wellhead of this well is confirmed to be a pure gas well. In the figure, FDENNFC in the "Fluid Density Channel" is the fluid density curve calculated using neutron lifetime logging data from 2021, and FDEN is the fluid density curve recorded from production profile logging data from 2019.

[0086] In the liquid accumulation section below 3740 meters, the density measured in the 2019 production profile was 1.27 g / cm³. 3 The density value calculated using neutron lifetime is 1.2 g / cm³. 3 The relative error is within 10%; in the pure gas section above 3720 meters, the density value measured in the 2019 production profile was 0.225 g / cm³. 3 The density value calculated using neutron lifetime is 0.225 g / cm³. 3 Nearby, with a relative error within 10%.

[0087] As can be clearly seen from the figure, compared with 2019, the fluid level in the wellbore has increased from 3740 meters to 3720 meters. Although no water has been encountered in this well and the gas production at the wellhead has not changed, the production situation downhole has changed. This shows that the use of neutron lifetime logging data has provided oil and gas reservoir researchers with information on the downhole production situation and provided key decision-making basis for optimizing the monitoring plan of this well.

[0088] This invention provides a system for obtaining wellbore fluid density, comprising:

[0089] The acquisition module is used to acquire the burst peak count rate curve from the neutron lifetime logging capture time spectrum data and obtain the burst peak decay rate.

[0090] The conversion module is used to construct a calibration relationship between wellbore fluid density data obtained from production profile logging and burst peak decay rate, and obtain the conversion relationship between burst peak decay rate and fluid density.

[0091] The output module is used to obtain the wellbore fluid density curve based on the conversion relationship between the burst peak decay rate and fluid density.

[0092] In another embodiment of the present invention, a computer device is provided, comprising a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing and control core of the terminal, suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions in the computer storage medium to achieve a corresponding method flow or corresponding function. The processor described in this embodiment of the present invention can be used in the operation of a method for obtaining wellbore fluid density.

[0093] In another embodiment of the present invention, a storage medium is provided, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device used to store programs and data. It is understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and extended storage media supported by the computer device. The computer-readable storage medium provides storage space that stores the operating system of the terminal. Furthermore, the storage space also stores one or more instructions suitable for loading and execution by a processor, which can be one or more computer programs (including program code). It should be noted that the computer-readable storage medium here can be high-speed RAM or non-volatile memory, such as at least one disk storage device. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the method for obtaining wellbore fluid density in the above embodiments.

[0094] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0095] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0096] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0097] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for obtaining wellbore fluid density, characterized in that, Includes the following steps: The burst peak count rate curve was acquired from the neutron lifetime logging capture time spectrum data, and the burst peak decay rate was obtained. Based on the wellbore fluid density data obtained from the production profile logging and the burst peak decay rate, a calibration relationship is constructed to obtain the conversion relationship between the burst peak decay rate and fluid density. The wellbore fluid density curve is obtained based on the conversion relationship between the burst peak decay rate and fluid density. The process of obtaining the burst peak decay rate is as follows: DENF = (MAXN - MAXF) / MAXN * 100%; Where DENF is the burst peak decay rate, MAXN is the near-probe burst peak, and MAXF is the far-probe burst peak.

2. The method for obtaining wellbore fluid density according to claim 1, characterized in that, The process of acquiring the burst peak count rate curve from the neutron lifetime logging capture time spectrum data is as follows: Within a preset range of neutron lifetime logging capture time spectrum data, burst peaks within the preset range are obtained. The burst peaks are the highest count rates, and the burst peak count rates are obtained by sorting.

3. The method for obtaining wellbore fluid density according to claim 2, characterized in that, The process of obtaining the burst peak decay rate is as follows: Within the preset range of neutron lifetime logging capture time spectrum data, the capture time spectrum data of near and far probes are processed to obtain the burst peak count rate curve of near and far probes. The curve value is the burst peak value of near and far probes. The burst peak attenuation rate was obtained based on the burst peak value of the far probe and the burst peak value of the near probe.

4. The method for obtaining wellbore fluid density according to claim 1, characterized in that, If the burst peak attenuation rate has curve spikes that affect the clarity of the curve, then a filtering method is used to remove the curve spikes.

5. The method for obtaining wellbore fluid density according to claim 1, characterized in that, The process of establishing a calibration relationship between wellbore fluid density data obtained from production profile logging and burst peak decay rate, and obtaining the conversion relationship between burst peak decay rate and fluid density, is as follows: Based on the production profile and neutron lifetime logging information simultaneously recorded from some wells, a calibration relationship is constructed using the fluid density data obtained from the production profile logging and the burst peak decay rate: FDENNFC = A * DENF + B; In the formula: FDENNFC is the wellbore fluid density curve; FDEN is the fluid density; A is the multiplication coefficient; B is the addition coefficient.

6. The method for obtaining wellbore fluid density according to claim 5, characterized in that, The process of obtaining the wellbore fluid density curve based on the conversion relationship between the burst peak decay rate and fluid density is as follows: The FDENNFC wellbore fluid density curve is used as the wellbore fluid density curve to indicate the location of fluid accumulation in the wellbore.

7. A system for obtaining wellbore fluid density, characterized in that, A method for obtaining wellbore fluid density according to any one of claims 1-6 includes: The acquisition module is used to acquire the burst peak count rate curve from the neutron lifetime logging capture time spectrum data and obtain the burst peak decay rate. The conversion module is used to construct a calibration relationship between wellbore fluid density data obtained from production profile logging and burst peak decay rate, and obtain the conversion relationship between burst peak decay rate and fluid density. The output module is used to obtain the wellbore fluid density curve based on the conversion relationship between the burst peak decay rate and fluid density. The process of obtaining the burst peak decay rate is as follows: DENF = (MAXN - MAXF) / MAXN * 100%; Where DENF is the burst peak decay rate, MAXN is the near-probe burst peak, and MAXF is the far-probe burst peak.

8. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of a method for obtaining wellbore fluid density as described in any one of claims 1-6.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of a method for obtaining wellbore fluid density as described in any one of claims 1-6.

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