Method and system for testing oil and gas production profile based on distributed optical fiber

Abstract

The present application relates to the technical field of oil and gas well production testing and downhole monitoring, in particular to a testing method and system for oil and gas production profile based on distributed optical fiber. The method is to lay distributed optical fiber along the target oil and gas well bore, set response area, control area and global reference area; implement wellhead throttling adjustment according to wellhead throttling opening degree change timing within the preset testing period, synchronously collect distributed optical fiber monitoring data and wellhead total production data; preprocess well bore monitoring data, construct interval differential response sequence of each target production layer, carry out demixing solution and quadratic programming solution, obtain final production contribution of each target production layer and generate oil and gas production profile. The method can reduce the influence of multi-layer response mixture on the test results, improve the stratification identification accuracy, quantitative solution ability and result stability under the condition of multi-layer commingled production.

Description

Technical Field

[0001] This invention relates to the field of oil and gas well production testing and downhole monitoring technology, specifically to a testing method and system for oil and gas production profiles based on distributed optical fibers. Background Technology

[0002] As oil and gas field development evolves from early single-well intermittent evaluation to refined and dynamic development management, oil and gas well dynamic monitoring technology is also gradually developing from phased testing methods such as well testing, production logging, and tracer testing to continuous monitoring throughout the entire life cycle. Especially with the continuous increase in the number of horizontal wells, stratified production wells, complex completion wells, and old wells with high water cut, traditional single, short-term, and point-based testing methods are no longer sufficient to meet the needs of continuous monitoring and refined interpretation.

[0003] In recent years, distributed optical fiber sensing technology has been gradually applied to the field of dynamic monitoring of oil and gas wells due to its advantages such as high monitoring density, fast response speed, high sensitivity, high temperature resistance, high pressure resistance, corrosion resistance, and suitability for long-term deployment throughout the well section. It has also been developed into various deployment methods, including retrievable, semi-permanent, and permanent types. Currently, distributed optical fibers are used in monitoring scenarios such as water absorption profiles, production profiles, and leak detection, providing a new technical means for identifying dynamic changes in the wellbore.

[0004] However, existing methods for testing oil and gas production profiles based on distributed optical fibers still have the following shortcomings: First, existing testing processes mostly focus on directly collecting distributed monitoring data from the wellbore under natural production conditions, lacking a zonal testing mechanism that establishes response locations, background locations, and whole-well reference locations around the target producing layer. This results in the mixing of local production responses from different layers with wellbore background responses and whole-well common-mode disturbances, affecting the accuracy of layer identification. Second, existing testing processes typically lack a testing method that actively disturbs the wellhead flow state through pre-set operating condition adjustment sequences, making it difficult to improve... The ability to distinguish the responses of different target producing layers is not conducive to the layer identification under multi-layer synergistic production conditions; thirdly, the existing interpretation process mostly relies on the direct interpretation of the original monitoring curves or local features, lacking a separate solution process to establish a correspondence between the multi-layer segment response and the total wellhead output, and also lacking a unified solution mechanism that combines constraints such as the total wellhead output, the non-negativity of segment output, and the continuity of inter-layer response. Therefore, in the case of multi-layer synergistic production, significant inter-layer interference, weak producing layer response not prominent, or large fluctuations in wellbore operating conditions, it is easy to encounter problems such as unclear segment contribution and insufficient reliability of production profile. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a testing method and system for oil and gas production profiles based on distributed optical fibers, thus solving the aforementioned problems.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the present invention provides the following technical solution: a method for testing oil and gas production profiles based on distributed optical fibers, comprising:

[0009] S1. Distributed optical fibers are laid along the wellbore of the target oil and gas well, and response zones, control zones, and global reference zones for non-producing well sections located outside all target producing layers are set up.

[0010] S2. Within the preset test cycle, implement wellhead throttling adjustment according to the preset wellhead throttling opening change sequence, and simultaneously collect distributed fiber optic monitoring data of each response zone, each control zone and the global reference zone as wellbore monitoring data, and obtain the total wellhead production data.

[0011] S3. After performing time alignment, depth alignment and baseline correction on the wellbore monitoring data, calculate the difference between the wellbore monitoring data of the response area and the control area corresponding to each target producing layer, and perform common mode correction in combination with the wellbore monitoring data of the global reference area to obtain the layer differential response sequence.

[0012] S4. Construct the total wellhead production response based on the total wellhead production data, and express it as the superposition response of the segment difference response sequence of each target production layer. Use least squares or least squares with regularization term to solve for the contribution coefficients corresponding to each target production layer, and determine the initial contribution of each target production layer accordingly.

[0013] S5. Using the final output contribution of each target production layer as the optimization variable, construct an objective function consisting of fitting terms and continuity terms. Under the constraints of total wellhead production and non-negative production of the layer, use quadratic programming to solve the problem and obtain the final output contribution of each target production layer.

[0014] S6. Generate the oil and gas production profile of the target oil and gas well based on the final production contribution of each target producing layer and the corresponding depth range.

[0015] Furthermore, the setting of response zones, control zones, and global reference zones for non-producing well sections located outside all target producing layers, corresponding to each target producing layer, includes:

[0016] For each target production layer, a response zone and a control zone are set up;

[0017] The global reference zone is set in the non-producing well section outside all the target producing layers.

[0018] Furthermore, the perforation segment corresponding to each target production layer is set as a response zone, and the distributed optical fiber is attached and fixed to the outer wall of the tubing or the inner side of the casing by means of metal clamps, compression bands or attachment fasteners.

[0019] The non-producing section adjacent to each of the target producing layers is set as a control area, and the distributed optical fiber is spaced apart from the tubing or casing by setting a spacer or protective sleeve between the distributed optical fiber and the tubing or casing.

[0020] Furthermore, the timing sequence of the wellhead throttling opening change is a sequence of throttling opening changes composed of multiple adjustment states in sequence, with each adjustment state corresponding to a determined throttling opening and duration;

[0021] The implementation of wellhead throttling adjustment includes adjusting the opening degree of the wellhead throttling device sequentially according to the time sequence of changes in the wellhead throttling opening degree.

[0022] Furthermore, obtaining the segmental differential response sequence of the target producing layer includes:

[0023] For each target production layer, calculate the difference between the distributed optical fiber monitoring data of its corresponding response area and the distributed optical fiber monitoring data of its corresponding control area;

[0024] Based on the distributed optical fiber monitoring data of the global reference area, common-mode correction is performed on the difference to obtain the segment differential response sequence of the target production layer.

[0025] Furthermore, before calculating the difference between the distributed optical fiber monitoring data of the corresponding response area and the distributed optical fiber monitoring data of the corresponding control area, the method further includes:

[0026] Time alignment, depth alignment, and baseline correction are performed on the distributed optical fiber monitoring data of the response area, the control area, and the global reference area.

[0027] Furthermore, the step of using least squares or least squares with regularization to unmix and solve for the contribution coefficients corresponding to each target production layer, and determining the initial contribution of each target production layer accordingly, includes:

[0028] The total wellhead production response is represented as a superposition of the segmental differential response sequences of multiple target producing layers;

[0029] The contribution coefficients corresponding to the differential response sequences of each segment are solved by least squares or least squares with regularization.

[0030] The initial contribution of each target producing layer to the total wellhead output is determined based on the contribution coefficients described above.

[0031] Furthermore, determining the initial contribution of each target producing layer to the total wellhead production based on each of the aforementioned contribution coefficients includes:

[0032] The contribution coefficients corresponding to each target production layer are normalized to obtain the initial contribution ratios corresponding to each target production layer.

[0033] When some contribution coefficients are negative, the negative values ​​are limited to zero before normalization is performed.

[0034] Based on the initial contribution ratio of each target producing layer and the total wellhead production data, the initial contribution of each target producing layer to the total wellhead production is determined.

[0035] Furthermore, S5 includes:

[0036] Using the final production contribution of each target production layer as the optimization variable, an objective function consisting of a fitting term and a continuity term is constructed. The fitting term represents the deviation between the final production contribution of each target production layer and the initial contribution, and the continuity term represents the difference in the final production contribution of adjacent target production layers at different well depths.

[0037] Under the constraints of total wellhead production and non-negative layer production, quadratic programming is used to solve the objective function to obtain the final production contribution of each target production layer.

[0038] The present invention also provides a testing system for oil and gas production profiles based on distributed optical fibers, including distributed optical fibers, a condition disturbance unit, a monitoring and acquisition unit, and a processing unit.

[0039] The distributed optical fiber is deployed along the wellbore of the target oil and gas well.

[0040] The processing unit is used to set up response zones, control zones, and global reference zones for non-producing well sections located outside all target producing layers, corresponding to each target producing layer.

[0041] The operating condition disturbance unit is used to implement wellhead throttling adjustment according to the preset wellhead throttling opening change sequence within a preset test cycle;

[0042] The monitoring and acquisition unit is used to synchronously acquire distributed optical fiber monitoring data of each response zone, each control zone and the global reference zone as wellbore monitoring data, and to obtain the total wellhead production data.

[0043] The processing unit is also used to perform time alignment, depth alignment and baseline correction on the wellbore monitoring data, calculate the difference between the wellbore monitoring data of the response area and the control area corresponding to each target producing layer, and perform common mode correction in combination with the wellbore monitoring data of the global reference area to obtain the layer differential response sequence.

[0044] The processing unit is also used to construct a total wellhead production response based on the total wellhead production data, and to express the total wellhead production response as a superposition response of the segment difference response sequence of each target production layer, and to solve the contribution coefficient corresponding to each target production layer by least squares or least squares unmixing with regularization term, and to determine the initial contribution of each target production layer accordingly.

[0045] The processing unit is also used to construct an objective function consisting of fitting terms and continuity terms, with the final output contribution of each target production layer as the optimization variable, and to solve it using quadratic programming under the constraints of total wellhead production and non-negative production of the layer, so as to obtain the final output contribution of each target production layer.

[0046] The processing unit is also used to generate oil and gas production profiles of target oil and gas wells based on the final production contribution of each target producing layer and the corresponding depth range.

[0047] (III) Beneficial Effects

[0048] Compared with existing technologies, this invention provides a method and system for testing oil and gas production profiles based on distributed optical fibers, which has the following advantages:

[0049] The present invention provides a method and system for testing oil and gas production profiles based on distributed optical fibers. This method involves setting response zones, control zones, and global reference zones corresponding to each target production layer in the wellbore of the target oil and gas well. Within a preset testing period, wellhead throttling is implemented according to a pre-defined sequence of wellhead throttling opening changes. Layer-specific differential response sequences are constructed using distributed optical fiber monitoring data from each response zone, control zone, and global reference zone. Then, the layer-specific differential response sequences of each target production layer are unmixed and solved based on the total wellhead production response. Furthermore, optimization is performed by incorporating total wellhead production constraints, layer-specific production non-negativity constraints, and continuity constraints. This approach helps reduce the mixing between local production responses of different layers and wellbore background responses and overall wellbore common-mode disturbances, improving the identifiability of responses from different target production layers. It also establishes a correspondence between multi-layer segment responses and total wellhead production, thereby improving the layer identification accuracy, quantitative solution capability, and result stability of the oil and gas production profile testing results. Attached Figure Description

[0050] Figure 1 A flowchart of the testing method for oil and gas production profiles based on distributed optical fibers provided by the present invention.

[0051] Figure 2 This is a schematic diagram showing the partitioning of the response zone, control zone, and global reference zone in the target oil and gas well provided by the present invention.

[0052] Figure 3 A schematic diagram illustrating the principle of the distributed optical fiber monitoring structure provided by this invention.

[0053] Figure 4 A schematic diagram illustrating the principle of distributed optical fiber scattering monitoring provided by this invention.

[0054] Figure 5 The system structure block diagram of the oil and gas production profile testing system based on distributed optical fiber provided by the present invention. Detailed Implementation

[0055] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0056] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0057] Please see Figure 3-4 , Figure 3 This is a schematic diagram of the distributed optical fiber monitoring structure provided by the present invention; Figure 4 This is a schematic diagram illustrating the distributed fiber optic scattering monitoring principle provided by the present invention. A ground-based light source emits detection light pulses into an optical fiber deployed underground. These pulses are coupled into the fiber via a beam splitter and propagate along the fiber. During transmission, backscattered light is generated due to the influence of temperature, strain, and vibration states at various locations along the fiber. The receiving end receives and demodulates the backscattered light, thereby obtaining distributed monitoring data at different locations along the fiber. Different types of monitoring information can be obtained based on different scattering mechanisms: Raman scattering signals can be used to characterize temperature changes, Brillouin scattering signals can be used to characterize strain changes, and Rayleigh scattering signals can be used to characterize acoustic vibration changes. Because the optical fiber is continuously deployed along the wellbore, continuous sensing of state changes at different depths within the wellbore is possible.

[0058] Please see Figure 1 , Figure 1 A flowchart of the testing method for oil and gas production profiles based on distributed optical fibers provided by the present invention.

[0059] Testing methods for oil and gas production profiles based on distributed optical fibers include:

[0060] S1. Distributed optical fibers are laid along the wellbore of the target oil and gas well, and response zones, control zones, and global reference zones for non-producing well sections located outside all target producing layers are set up.

[0061] Specifically, distributed optical fibers are deployed longitudinally along the wellbore of the target oil and gas well, covering the well sections corresponding to each target producing layer and the non-producing well sections located outside each target producing layer. Based on the well depth of each target producing layer, the well sections covered by the distributed optical fibers are divided into zones to form a response zone for characterizing the local response of the target producing layer, a control zone for characterizing the background response of adjacent well sections, and a global reference zone for characterizing the common disturbance of the entire well. The global reference zone is set separately from the production location of the target producing layer and is used to extract the common variation components within the entire well range.

[0062] For further details, please refer to Figure 2 , Figure 2 This is a schematic diagram illustrating the partitioning of the response zone, control zone, and global reference zone in the target oil and gas well provided by the present invention. In one embodiment of this application, a response zone, a control zone corresponding to each target producing layer, and a global reference zone located in the non-producing well section outside all target producing layers are provided, including:

[0063] Set up a response zone and a control zone for each target product layer;

[0064] The global reference zone is set in the non-producing well section outside all target producing layers.

[0065] Specifically, taking multiple target producing layers distributed sequentially along the well depth as the object, the well is partitioned according to the method of one layer corresponding to one zone. The target production layer corresponds to the first The first response zone and the first There are control areas, among which , The total number of target producing layers; the global reference zone is located in the non-producing well section outside all target producing layers. This well section does not overlap with the perforated section of any target producing layer and is used to output the common-mode disturbance signal of the entire well. After adopting the above one-to-one correspondence partitioning method, each target producing layer has an independent local response acquisition position and an adjacent background acquisition position, and the global reference zone outputs the common wellbore variation separately.

[0066] Furthermore, in one embodiment provided in this application, the perforation segment corresponding to each target production layer is set as a response zone, and the distributed optical fiber is attached and fixed to the outer wall of the tubing or the inner side of the casing by means of metal clamps, compression bands or attachment fasteners.

[0067] The non-producing section adjacent to each target producing layer is set as a control area, and the distributed optical fiber is spaced apart from the tubing or casing by setting spacers or protective sleeves between the distributed optical fiber and the tubing or casing.

[0068] Specifically, the response zone directly corresponds to the perforated section of the target producing formation. In this zone, the distributed optical fiber is fixed to the outer wall of the tubing or the inner side of the casing using metal clamps, compression bands, or adhesive fasteners, ensuring close contact between the distributed optical fiber and the wellbore structure. The control zone selects a continuous non-producing section adjacent to or above the perforated section. In this section, spacers or protective sleeves are used to create a gap between the distributed optical fiber and the tubing or casing. Thus, the response zone outputs the local response signal corresponding to the perforated section, while the control zone outputs the background response signal of the adjacent non-producing section. These two types of sections form a paired acquisition relationship within the same well depth range.

[0069] S2. Within the preset test cycle, implement wellhead throttling adjustment according to the preset wellhead throttling opening change sequence, and simultaneously collect distributed fiber optic monitoring data of each response zone, each control zone and the global reference zone as wellbore monitoring data, and obtain the total wellhead production data.

[0070] Specifically, within a preset test period, the wellhead flow conditions are adjusted sequentially using a wellhead throttling device. Distributed fiber optic monitoring data for each response zone, control zone, and global reference zone are collected synchronously during each adjustment period, along with total wellhead output data. The distributed fiber optic monitoring data forms a wellbore monitoring data sequence in chronological order, while the total wellhead output data forms a total wellhead output data sequence within the same test period. Both are recorded correspondingly within the same test period to characterize the relationship between the wellbore friction response and the change in total wellhead output during the wellhead throttling adjustment process.

[0071] Furthermore, in one embodiment provided in this application, the timing sequence of wellhead throttling opening change is a throttling opening change sequence composed of multiple adjustment states in sequence, with each adjustment state corresponding to a determined throttling opening and duration;

[0072] Implementing wellhead throttling regulation involves adjusting the opening of the wellhead throttling device sequentially according to the time sequence of changes in the wellhead throttling opening.

[0073] Specifically, let's assume there are a total of In each adjustment state, the time sequence of wellhead throttling opening change is expressed as: ;in, Indicates the first The throttling opening corresponding to each adjustment state Indicates the first The duration of each adjustment state, During testing, the wellhead throttling device was activated in sequence. The order of each adjustment state is sequentially switched to the corresponding opening degree, and after maintaining the corresponding duration, it enters the next adjustment state. Each adjustment state can use a sequential combination of different opening degree values, or a combination of repeatedly occurring opening degree values, thereby forming a wellhead flow condition that changes in stages within the test cycle. Distributed fiber optic monitoring data of each response zone, each control zone, and the global reference zone, as well as the total wellhead production data, are continuously collected and saved according to time stamps during the duration of each adjustment state to form a data sequence corresponding to the time sequence of wellhead throttling opening degree changes.

[0074] S3. After performing time alignment, depth alignment and baseline correction on the wellbore monitoring data, calculate the difference between the wellbore monitoring data of the response zone and the control zone corresponding to each target producing layer, and perform common mode correction in combination with the wellbore monitoring data of the global reference zone to obtain the layer differential response sequence.

[0075] Specifically, the wellbore monitoring data collected during the test period for each response zone, control zone, and global reference zone are uniformly processed to ensure that the data from different sections correspond to each other under the same time coordinate and the same well depth coordinate. After preprocessing, the monitoring data sequences of the corresponding response zone, control zone, and global reference zone are extracted for each target producing layer. First, the difference sequence between the response zone and the control zone is calculated. Then, the common variation components within the entire well range are subtracted using the monitoring data sequence corresponding to the global reference zone to output the segment differential response sequence corresponding to the target producing layer. A set of segment differential response sequences is obtained for each target producing layer to characterize the net response process of each target producing layer during the test period.

[0076] Furthermore, in one embodiment provided in this application, obtaining the segmental differential response sequence of the target producing layer includes:

[0077] For each target production layer, calculate the difference between the distributed optical fiber monitoring data of the corresponding response area and the distributed optical fiber monitoring data of the corresponding control area;

[0078] Based on the distributed optical fiber monitoring data of the global reference area, common mode correction is performed on the difference to obtain the segment differential response sequence of the target production layer.

[0079] Specifically, let the first The target production layer at time The response segment value is The segment value of the comparison area is The global reference area segment value is The values ​​for the response zone, control zone, and global reference zone can be obtained by averaging the monitoring values ​​of each sampling point within the corresponding zone, i.e.: , , ;in, Indicates the first The number of sampling points within the response region corresponding to each target production layer Indicates the first The number of sampling points in the control area corresponding to each target producing layer This indicates the number of sampling points within the global reference area. Indicates the first Within the response zone corresponding to the target production layer, the first... Each sampling point at time... The monitoring value, ; Indicates the first The target production layer corresponds to the first [number] in the control area. Each sampling point at time... The monitoring value, ; Indicates the first [number] in the global reference zone Each sampling point at time... The monitoring value, .

[0080] After obtaining the values ​​of each segment, first calculate the first... The segment difference sequence corresponding to each target producing layer: Then, common mode correction is performed based on the segment values ​​of the global reference region to obtain the first... The segmental differential response sequence corresponding to each target production layer: or ;in, For the first The common mode correction coefficients corresponding to each target production layer. Therefore, Characterizing the first The target production layer at time The net response value relative to changes in the adjacent background and changes across the entire well.

[0081] Furthermore, in one embodiment provided in this application, before calculating the difference between the distributed optical fiber monitoring data of the corresponding response area and the distributed optical fiber monitoring data of the corresponding control area, the method further includes:

[0082] Time alignment, depth alignment, and baseline correction were performed on the distributed optical fiber monitoring data of the response area, the control area, and the global reference area.

[0083] Specifically, time alignment is used to map the raw monitoring data of each segment to the same target time axis. Above; for data whose original sampling time is inconsistent with the target time axis, interpolation can be used to obtain aligned monitoring values, i.e.: ;in, Indicates the original monitoring sequence. This represents the monitoring value after being mapped to the target time axis.

[0084] Depth alignment is used to map the distributed fiber length coordinates to a unified well depth coordinate, so that the response area, control area and global reference area can extract segment data under the same well depth reference.

[0085] Baseline correction is used to eliminate the influence of initial state differences before the start of the test on subsequent differential calculations; for any sampling point within any segment, correction can be performed based on the average value of the baseline time period, i.e.: ;in, This represents the average value of the monitored values ​​at the corresponding sampling points during the baseline period before the test begins. This indicates the monitored value after baseline correction.

[0086] After time alignment, depth alignment and baseline correction, the data of the response area, control area and global reference area are correlated under the same time coordinate and well depth coordinate, and then the section difference calculation and common mode correction steps are performed.

[0087] S4. Construct the total wellhead production response based on the total wellhead production data, and express it as the superposition response of the segment difference response sequence of each target production layer. Use least squares or least squares with regularization term to solve for the contribution coefficients corresponding to each target production layer, and determine the initial contribution of each target production layer accordingly.

[0088] Specifically, the total wellhead production data is arranged along a uniform time axis within the testing period, forming a total wellhead production response sequence. Assume there are a total of [number missing] wellhead production data within the testing period. Each sampling time The total wellhead production response vector is denoted as: ,in, Indicates time The total production response value at the wellhead. For the first... For each target production layer, the corresponding layer segment differential response sequence is obtained based on step S3: ,in, , This represents the total number of target producing layers. The differential response sequences of each target producing layer are combined column-wise to obtain the response matrix. The total wellhead production response is represented as the superposition of the differential response sequences of each target producing layer, i.e.: Or, as written: ,in, , Indicates the first The contribution coefficients corresponding to each target producing layer are established using the above expression. This establishes a correspondence between the total wellhead production response and the segmental differential response sequences of each target producing layer, followed by the step of calculating the contribution coefficients.

[0089] Furthermore, in one embodiment provided in this application, the contribution coefficients corresponding to each target productive layer are solved using least squares or least squares with regularization terms to unmix the solution, and the initial contribution of each target productive layer is determined accordingly, including:

[0090] The total wellhead production response is represented as the superposition response of the segmental differential response sequences of multiple target producing layers;

[0091] The contribution coefficients corresponding to the difference response sequences of each segment are solved by least squares or least squares with regularization terms.

[0092] The initial contribution of each target producing layer to the total wellhead output is determined based on the contribution coefficients.

[0093] Specifically, when using least squares, the objective is to minimize the sum of squared residuals between the total wellhead production response and the superimposed response, and the solution formula is constructed as follows: ,in, This represents the total wellhead production response vector. This represents the response matrix composed of the column-wise differential response sequences of each target production layer segment. This represents the contribution coefficient vector corresponding to each target production layer. This represents the optimal contribution coefficient vector obtained from the solution. Let L2 be the norm. Solving for L2 yields the contribution coefficients corresponding to each target product layer. When there is a strong correlation between the segment difference response sequences corresponding to multiple target production layers, a regularization term is added to the sum of squared residuals to construct a least-squares solution with a regularization term: ,in, This represents the regularization coefficient. Through this solution process, the contribution coefficient vector of each target producing layer to the total wellhead production response during the testing period is obtained. Then, the contribution coefficient is converted into the initial contribution amount.

[0094] Furthermore, in one embodiment provided in this application, determining the initial contribution of each target producing layer to the total wellhead production based on each contribution coefficient includes:

[0095] The contribution coefficients of each target production layer are normalized to obtain the initial contribution ratio of each target production layer.

[0096] When some contribution coefficients are negative, the negative values ​​are limited to zero before normalization is performed.

[0097] Based on the initial contribution ratio of each target producing layer and the total wellhead production data, determine the initial contribution of each target producing layer to the total wellhead production.

[0098] Specifically, the contribution coefficient is first processed to be non-negative, resulting in: ,in, Indicates the first The contribution coefficients of each target producing layer are obtained after non-negation processing. Then, the non-negation contribution coefficients of all target producing layers are normalized to obtain the initial contribution ratios. ,in, Indicates the first The initial contribution ratio corresponding to each target production layer.

[0099] When the total wellhead production data adopts the total production of the test cycle When indicating, the first The initial contribution corresponding to each target production layer is: ,in, Indicates the first The initial contribution amount corresponding to each target production layer.

[0100] When the total wellhead production data is represented in time series form, the allocation values ​​corresponding to each sampling time can also be obtained first: Then, the results are accumulated according to the test cycle to obtain... Thus, each target producing layer obtains an initial contribution corresponding to the total wellhead production data.

[0101] S5. Using the final output contribution of each target production layer as the optimization variable, construct an objective function consisting of fitting terms and continuity terms. Under the constraints of total wellhead production and non-negative production of the layer, use quadratic programming to solve the problem and obtain the final output contribution of each target production layer.

[0102] Specifically, let the first The final output contribution of each target production layer is , No. The initial contribution of each target production layer is: The total number of target production layers is The total wellhead production is Using vectors As optimization variables, construct the objective function. ,in, Represents the fitted term, Indicates continuous terms, and This represents the weighting coefficients for the two terms. The fitting term, used to characterize the deviation between the final output contribution and the initial contribution, can be written as: ,in, Indicates the first The fitting weights corresponding to each target production layer.

[0103] The continuity term is used to characterize the difference between the final production contributions of adjacent target producing formations at different well depths, and can be written as: ,in, Indicates the first The target production layer and the first The continuity weights between target production layers.

[0104] The total wellhead production constraint is written as: .

[0105] The non-negativity constraint for segment output is written as: , .

[0106] After establishing the objective function and constraints, quadratic programming is used to solve for the final output contribution corresponding to each objective production level. .

[0107] Furthermore, in one embodiment provided in this application, S5 includes:

[0108] Using the final production contribution of each target production layer as the optimization variable, an objective function consisting of a fitting term and a continuity term is constructed. The fitting term represents the deviation between the final production contribution of each target production layer and the initial contribution, while the continuity term represents the difference in the final production contribution between adjacent target production layers at different well depths.

[0109] Under the constraints of total wellhead production and non-negative production of each layer, quadratic programming is used to solve the objective function to obtain the final production contribution of each target production layer.

[0110] Specifically, after taking the fitted term and the continuity term in squared form, the objective function can be expanded as follows: The first part distributes the final production contribution around the initial contribution, while the second part limits the contribution difference between adjacent target producing layers at well depths.

[0111] When the initial contribution of each target production layer has a basically consistent reliability, it can be taken as... When a uniform continuity weight is used between adjacent target producing layers at well depths, the following can be taken: At this point, the objective function simplifies to .

[0112] In the quadratic programming solution process, the total wellhead production constraint and the non-negativity constraint of the formation output are used as the boundaries of the feasible region. Within this feasible region, a solution vector that minimizes the objective function is searched. After the solution is completed, the final output contribution corresponding to each target production layer is obtained, where the th layer is... The final output contribution corresponding to each target production layer is denoted as When it is necessary to output the final output contribution ratio corresponding to each target production layer, further calculations can be performed: ,in Indicates the first The final output contribution ratio corresponding to each target production layer.

[0113] S6. Generate the oil and gas production profile of the target oil and gas well based on the final production contribution of each target producing layer and the corresponding depth range.

[0114] Specifically, the final production contribution of each target producing layer is correlated with the well depth range corresponding to each target producing layer. The final production contributions of each target producing layer are then arranged according to the well depth direction, forming an oil and gas production profile dataset. Let the first... The final output contribution corresponding to each target production layer is The corresponding depth range is Then the oil and gas production profile can be represented as: , , ,in, Indicates the depth of the well The corresponding production profile value is calculated. Based on the distribution order of each depth interval along the well depth direction, the final production contribution corresponding to each target producing layer is written into the corresponding depth interval, thus obtaining the stratified production distribution results of the target oil and gas well along the well depth direction.

[0115] In one embodiment, when it is necessary to output the output percentage of each target production layer, the first layer can be... The final output contribution ratio corresponding to each target production layer and depth range Corresponding relationships are established, and a normalized oil and gas production profile is generated; when the absolute production of each target production layer needs to be output, the final production is used directly. This serves as the profile value for the corresponding depth range. The generated oil and gas production profile can be output in the form of a list, table, or well depth distribution map, where each target producing layer corresponds to a set of depth range information and production contribution information.

[0116] Please see Figure 5 The present invention also provides a test system for oil and gas production profile based on distributed optical fiber, including distributed optical fiber, operating condition disturbance unit, monitoring and acquisition unit and processing unit.

[0117] Distributed optical fibers are deployed along the wellbore of the target oil and gas well.

[0118] The processing unit is used to set the response zone, control zone, and global reference zone for non-producing well sections located outside all target producing layers, corresponding to each target producing layer.

[0119] The operating condition disturbance unit is used to implement wellhead throttling adjustment according to the preset wellhead throttling opening change sequence within a preset test cycle;

[0120] The monitoring and acquisition unit is used to synchronously collect distributed fiber optic monitoring data from each response zone, each control zone, and the global reference zone as wellbore monitoring data, and to obtain total wellhead production data.

[0121] The processing unit is also used to perform time alignment, depth alignment and baseline correction on the wellbore monitoring data, calculate the difference between the wellbore monitoring data of the response area and the control area corresponding to each target production layer, and perform common mode correction in combination with the wellbore monitoring data of the global reference area to obtain the layer differential response sequence.

[0122] The processing unit is also used to construct the total wellhead production response based on the total wellhead production data, and to express the total wellhead production response as the superposition response of the segment difference response sequence of each target production layer. The least squares or least squares unmixing with regularization term is used to solve the contribution coefficient corresponding to each target production layer, and the initial contribution of each target production layer is determined accordingly.

[0123] The processing unit is also used to construct an objective function consisting of fitting terms and continuity terms, with the final output contribution of each target production layer as the optimization variable. Under the constraints of total wellhead production and non-negativity of layer production, quadratic programming is used to solve the objective function to obtain the final output contribution of each target production layer.

[0124] The processing unit is also used to generate oil and gas production profiles of target oil and gas wells based on the final production contribution of each target producing layer and the corresponding depth range.

[0125] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0126] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for testing an oil and gas production profile based on distributed optical fiber, characterized in that, include: S1. Distributed optical fibers are laid along the wellbore of the target oil and gas well, and response zones, control zones, and global reference zones for non-producing well sections located outside all target producing layers are set up. S2. Within the preset test cycle, implement wellhead throttling adjustment according to the preset wellhead throttling opening change sequence, and simultaneously collect distributed fiber optic monitoring data of each response zone, each control zone and the global reference zone as wellbore monitoring data, and obtain the total wellhead production data. S3. After performing time alignment, depth alignment and baseline correction on the wellbore monitoring data, calculate the difference between the wellbore monitoring data of the response area and the control area corresponding to each target producing layer, and perform common mode correction in combination with the wellbore monitoring data of the global reference area to obtain the layer differential response sequence. S4. Construct the total wellhead production response based on the total wellhead production data, and express it as the superposition response of the segment difference response sequence of each target production layer. Use least squares or least squares with regularization term to solve for the contribution coefficients corresponding to each target production layer, and determine the initial contribution of each target production layer accordingly. S5. Using the final output contribution of each target production layer as the optimization variable, construct an objective function consisting of fitting terms and continuity terms. Under the constraints of total wellhead production and non-negative production of the layer, use quadratic programming to solve the problem and obtain the final output contribution of each target production layer. S6. Generate the oil and gas production profile of the target oil and gas well based on the final production contribution of each target producing layer and the corresponding depth range.

2. The method of claim 1, wherein, The setting of response zones, control zones, and global reference zones corresponding to each target producing layer, as well as non-producing well sections located outside all target producing layers, includes: For each target production layer, a response zone and a control zone are set up; The global reference zone is set in the non-producing well section outside all the target producing layers.

3. The method for testing oil and gas production profiles based on distributed optical fibers according to claim 2, characterized in that: Each perforation segment corresponding to the target production layer is set as the response zone, and the distributed optical fiber is attached and fixed to the outer wall of the tubing or the inner side of the casing by metal clamps, compression bands or attachment fasteners. The non-producing section adjacent to each of the target producing layers is set as a control area, and the distributed optical fiber is spaced apart from the tubing or casing by setting a spacer or protective sleeve between the distributed optical fiber and the tubing or casing.

4. The method for testing oil and gas production profiles based on distributed optical fibers according to claim 1, characterized in that: The wellhead throttling opening change sequence is a throttling opening change sequence composed of multiple adjustment states in sequence, with each adjustment state corresponding to a determined throttling opening and duration; The implementation of wellhead throttling adjustment includes adjusting the opening degree of the wellhead throttling device sequentially according to the time sequence of changes in the wellhead throttling opening degree.

5. The method of claim 1, wherein, The process of obtaining the segmental differential response sequence of the target producing layer includes: For each target production layer, calculate the difference between the distributed optical fiber monitoring data of its corresponding response area and the distributed optical fiber monitoring data of its corresponding control area; Based on the distributed optical fiber monitoring data of the global reference area, common-mode correction is performed on the difference to obtain the segment differential response sequence of the target production layer.

6. The method of testing a distributed fiber based oil and gas production profile of claim 5, wherein, Before calculating the difference between the distributed optical fiber monitoring data of the corresponding response area and the distributed optical fiber monitoring data of the corresponding control area, the method further includes: Time alignment, depth alignment, and baseline correction are performed on the distributed optical fiber monitoring data of the response area, the control area, and the global reference area.

7. The method of testing a distributed fiber based oil and gas production profile of claim 1, wherein, The process of using least squares or least squares with regularization to unmix and solve for the contribution coefficients corresponding to each target production layer, and determining the initial contribution of each target production layer accordingly, includes: The total wellhead production response is represented as a superposition of the segmental differential response sequences of multiple target producing layers; The contribution coefficients corresponding to the differential response sequences of each segment are solved by least squares or least squares with regularization. The initial contribution of each target producing layer to the total wellhead output is determined based on the contribution coefficients described above.

8. The method of testing a distributed fiber based oil and gas production profile of claim 7, wherein, The determination of the initial contribution of each target producing layer to the total wellhead production based on the respective contribution coefficients includes: The contribution coefficients corresponding to each target production layer are normalized to obtain the initial contribution ratios corresponding to each target production layer. When some contribution coefficients are negative, the negative values ​​are limited to zero before normalization is performed. Based on the initial contribution ratio of each target producing layer and the total wellhead production data, the initial contribution of each target producing layer to the total wellhead production is determined.

9. The method of testing a distributed fiber based oil and gas production profile of claim 1, wherein, S5 includes: Using the final production contribution of each target production layer as the optimization variable, an objective function consisting of a fitting term and a continuity term is constructed. The fitting term represents the deviation between the final production contribution of each target production layer and the initial contribution, and the continuity term represents the difference in the final production contribution of adjacent target production layers at different well depths. Under the constraints of total wellhead production and non-negative layer production, quadratic programming is used to solve the objective function to obtain the final production contribution of each target production layer.

10. A distributed optical fiber based testing system for oil and gas production profile, characterized in that: It includes distributed optical fiber, operating condition disturbance unit, monitoring and acquisition unit and processing unit; The distributed optical fiber is deployed along the wellbore of the target oil and gas well. The processing unit is used to set up response zones, control zones, and global reference zones for non-producing well sections located outside all target producing layers, corresponding to each target producing layer. The operating condition disturbance unit is used to implement wellhead throttling adjustment according to the preset wellhead throttling opening change sequence within a preset test cycle; The monitoring and acquisition unit is used to synchronously acquire distributed optical fiber monitoring data of each response zone, each control zone and the global reference zone as wellbore monitoring data, and to obtain the total wellhead production data. The processing unit is also used to perform time alignment, depth alignment and baseline correction on the wellbore monitoring data, calculate the difference between the wellbore monitoring data of the response area and the control area corresponding to each target producing layer, and perform common mode correction in combination with the wellbore monitoring data of the global reference area to obtain the layer differential response sequence. The processing unit is also used to construct a total wellhead production response based on the total wellhead production data, and to express the total wellhead production response as a superposition response of the segment difference response sequence of each target production layer, and to solve the contribution coefficient corresponding to each target production layer by least squares or least squares unmixing with regularization term, and to determine the initial contribution of each target production layer accordingly. The processing unit is also used to construct an objective function consisting of fitting terms and continuity terms, with the final output contribution of each target production layer as the optimization variable, and to solve it using quadratic programming under the constraints of total wellhead production and non-negative production of the layer, so as to obtain the final output contribution of each target production layer. The processing unit is also used to generate oil and gas production profiles of target oil and gas wells based on the final production contribution of each target producing layer and the corresponding depth range.

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