A composite high-temperature-resistant tracer system for evaluating fire flooding sweep efficiency

Abstract

The present application belongs to the technical field of oil reservoir dynamic monitoring, and relates to a composite high-temperature-resistant tracer system for evaluating fire flooding sweep efficiency, which comprises: a composite tracer injection module for injecting a system containing inert reference and heat-sensitive precursor tracer into a target oil reservoir; an output fluid collection and detection module for detecting and obtaining the original concentrations of reference concentration and first and second characteristic fingerprint products generated by cracking of the heat-sensitive tracer; a model construction module for establishing a physical transmission standardization model based on the reference concentration; a decoupling module for calling the model to reversely decouple the original concentrations to generate net chemical yield; a calculation module for calculating the net chemical yield ratio of the two products to generate a thermal phase fingerprint index curve; and a report module for coupling analysis of the index and the reference concentration to determine the thermal level properties of the channel and generate a report. The present application solves the technical problem that the existing fire flooding evaluation method is difficult to accurately evaluate the effective heat sweep range due to the mutual coupling of physical migration process and thermal chemical reaction effect.

Description

Technical Field

[0001] This invention belongs to the technical field of reservoir dynamic monitoring and relates to a composite high-temperature resistant tracer system for evaluating fire flood sweep efficiency. Background Technology

[0002] Fire-driven oil recovery technology improves the recovery rate of heavy oil by injecting gas into the oil reservoir and igniting part of the reservoir, utilizing the heat generated by the combustion front. In this process, the characterization of the expansion range of the combustion front and the thermal field structure is of great significance for the optimization and adjustment of the development scheme.

[0003] Current technologies for evaluating the sweep efficiency of fire-driven operations mainly rely on methods such as temperature monitoring, conventional tracer testing, and numerical simulation. Temperature monitoring often involves acquiring local data through fixed measuring points, conventional tracer testing often uses chemically stable tracers to reflect the physical transport path of fluids, and numerical simulation is based on geological models for prediction. In addition, some technologies attempt to use tracers that can undergo thermal reactions, utilizing the decomposition or phase change characteristics of substances at specific temperatures to infer formation temperature information from the return data.

[0004] However, existing monitoring methods have limitations in terms of spatial coverage or prediction accuracy. Conventional tracers are difficult to distinguish the thermal properties of the area through which the fluid flows. Single thermal reaction tracer schemes usually lack reference benchmarks. The reduction in their returned concentration is affected by multiple effects such as physical dilution, formation adsorption, and chemical thermal decomposition. Existing technologies cannot effectively separate the above complex coupling effects, which makes it easy to be disturbed by changes in physical transport conditions when inverting the thermal field distribution based on the concentration curve, thus affecting the accuracy of the evaluation results. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a composite high-temperature resistant tracer system for evaluating fire drive sweep efficiency.

[0006] A composite high-temperature resistant tracer system for evaluating fire drive sweep efficiency includes: The composite tracer system injection module injects a composite tracer system containing an inert physical path reference tracer and a thermosensitive cascade reaction precursor tracer into the target reservoir to establish the initial state of underground fluid migration and thermochemical reactions. The produced fluid acquisition and detection module collects produced fluid samples from the production well, detects and obtains the baseline concentration value of the inert physical path baseline tracer, the first original concentration value of the first characteristic fingerprint product generated by the cracking of the thermal cascade reaction precursor tracer, and the second original concentration value of the second characteristic fingerprint product, and generates the original tracer response dataset. The physical transport model construction module calculates the physical retention coefficient and performs time series fitting based on the baseline concentration values ​​in the original tracer response dataset to generate a standardized physical transport model. The thermochemical production decoupling module calls the physical transport standardization model to perform physical attenuation reverse decoupling processing on the first and second original concentration values, generating a thermochemical evaluation dataset containing purification yield. The thermal phase fingerprint calculation module, based on the thermochemical evaluation dataset, calculates the ratio of the purification yield of the second characteristic fingerprint product to the purification yield of the first characteristic fingerprint product, and generates a thermal phase fingerprint index curve. The fire drive efficiency analysis report module couples the thermal phase fingerprint index curve with the baseline concentration value to determine the thermal level properties of the fluid channel and generate a fire drive sweep efficiency evaluation report.

[0007] A further aspect of the present invention provides a composite tracer system injection module, used to perform the following operations: Substances with a chemical decomposition initiation temperature higher than the preset highest expected temperature of the combustion front were selected as inert physical path reference tracers. A thermosensitive cascade reaction precursor tracer with hierarchical thermal decomposition characteristics was synthesized. A first thermosensitive bond and a second thermosensitive bond were pre-positioned in the molecular structure. The first thermosensitive bond was broken in the temperature range of the vapor zone to generate a first characteristic fingerprint product, and the second thermosensitive bond was broken in the core temperature range of the combustion front to generate a second characteristic fingerprint product. An inert physical path reference tracer is mixed with a thermosensitive cascade reaction precursor tracer to form a composite tracer system, which is then injected into the formation through an injection well.

[0008] A further aspect of the present invention provides a fluid acquisition and detection module for performing the following steps: Collect output fluid samples at preset time intervals and perform gas-liquid separation pretreatment on the samples; Using chromatography-mass spectrometry (GC-MS) analysis, based on retention time and mass-to-charge ratio characteristics, inert physical pathway reference tracers, first characteristic fingerprint products, and second characteristic fingerprint products in fluid samples are identified and quantified. The detected baseline concentration value, the first original concentration value, and the second original concentration value are correlated with the sampling time point to construct the original tracer response dataset.

[0009] A further aspect of the present invention includes a physical transmission model construction module, which performs the following operations: Obtain the initial total injected mass of the inert physical path reference tracer and the formation pore volume parameters of the target reservoir; Extract the baseline concentration value at each sampling time, calculate the product of the baseline concentration value and the formation pore volume parameter, and divide the product by the initial total injected mass to obtain the physical retention coefficient at that sampling time. Numerical regression algorithms were applied to fit the physical retention coefficients at different sampling times, and a functional relationship describing the continuous change of the physical retention coefficients over time was established as a standardized model for physical transmission.

[0010] A further aspect of the present invention includes a thermochemical generation decoupling module, used to perform the following operations: Substitute the sampling time point into the physical transport normalization model to calculate the physical retention coefficient for correction at that moment; Divide the first original concentration value by the physical retention coefficient for correction to obtain the purification yield of the first characteristic fingerprint product; Divide the second original concentration value by the physical retention coefficient for correction to obtain the purification yield of the second characteristic fingerprint product; The purification yields of the first and second characteristic fingerprint products calculated at each time point are stored in time series to generate a thermochemical evaluation dataset.

[0011] A further aspect of the present invention includes a thermal phase fingerprint calculation module, used to perform the following steps: The purification yield of the second characteristic fingerprint product and the purification yield of the first characteristic fingerprint product at the same sampling time were extracted from the thermochemical evaluation dataset. Calculate the dimensionless ratio of the purification yield of the second characteristic fingerprint product to the purification yield of the first characteristic fingerprint product, and define this ratio as the thermal phase fingerprint index at that moment. Arrange the calculated thermal phase fingerprint indices in chronological order and plot the generated thermal phase fingerprint index curve.

[0012] A further aspect of the present invention is a fire-drive efficiency analysis report module, used to perform the following operations: Set high-temperature combustion threshold, low-temperature steam threshold, and cross-flow judgment concentration threshold; If the thermal phase fingerprint index is higher than the high-temperature combustion threshold, the current moment is determined to be an effective combustion-driven oil passage; if the thermal phase fingerprint index is between the high-temperature combustion threshold and the low-temperature steam threshold, the current moment is determined to be the steam-dominated stage. If the thermal phase fingerprint index is lower than the low-temperature steam threshold and the corresponding baseline concentration value is higher than the crossflow judgment concentration threshold, the current moment is determined to be an invalid low-temperature crossflow channel; The distribution of thermal properties of each fluid channel is statistically analyzed to generate a fire drive sweep efficiency evaluation report.

[0013] A further aspect of the present invention, forming a composite tracer system, includes: Set the preset mass ratio; Based on the relationship that the total mass of the thermal cascade reaction precursor tracer and the total mass of the inert physical path reference tracer satisfy a preset mass ratio, the required mass of each component is calculated. An automated injection control system is used to regulate the metering pump, delivering the two tracers to an online mixer for mixing according to the calculated required mass.

[0014] A further aspect of the present invention includes calculating the dimensionless ratio: Determine whether the purification yield of the first feature fingerprint product is lower than the preset signal-to-noise ratio threshold; If so, the thermal fingerprint index will be directly set to the preset saturation upper limit value; If not, then perform the operation of calculating the dimensionless ratio of the purification yield of the second characteristic fingerprint product to the purification yield of the first characteristic fingerprint product.

[0015] A further aspect of the present invention, in generating a fire drive sweep efficiency evaluation report, includes: The duration or cumulative fluid flux of the effective combustion-driven oil flow channel, the steam zone-dominated stage, and the ineffective low-temperature crossflow channel during the monitoring period was statistically analyzed. For areas identified as ineffective cryogenic crossflow channels, develop fire-drive development adjustment strategies that include adjusting the gas injection rate or selective water shut-off operations, and include these strategies in the fire-drive spillover efficiency evaluation report.

[0016] In summary, the present invention has the following beneficial technical effects: 1. This invention employs a composite tracer system comprising an inert physical path reference tracer and a thermosensitive cascade reaction precursor tracer. The inert tracer marks the physical transport path of the fluid, while the thermosensitive tracer utilizes the breaking characteristics of different thermosensitive bonds in its molecular structure within a specific temperature range to respond to the formation thermal field. This composite system design allows for the simultaneous acquisition of physical transport and thermochemical reaction information during a single injection operation, providing a material basis for distinguishing between physical dispersion effects and pyrolysis effects.

[0017] 2. This invention constructs a physical transport standardization model based on the concentration response of an inert physical path reference tracer, quantifying the signal attenuation caused by physical factors such as dilution, dispersion, and adsorption of the fluid from the injection end to the production end. This model is used to inversely correct the original concentration of the thermosensitive tracer product, calculating the purified chemical yield after eliminating physical transport interference. This decouples physical effects from thermochemical effects, reducing the impact of differences in physical transport caused by formation heterogeneity on the accuracy of thermal field evaluation.

[0018] 3. This invention establishes a thermal phase fingerprint index by calculating the dimensionless ratio of the purification yield of the second characteristic fingerprint product to that of the first characteristic fingerprint product. This index eliminates analytical errors caused by fluctuations in the total fluid production of the production well. Its numerical variation mainly depends on the temperature history of the fluid flow area, and can objectively characterize whether the fluid reaching the production well originates from the high-temperature combustion zone, the steam zone, or the low-temperature unaffected zone, which helps to grasp the propulsion pattern of the fire-driven front.

[0019] 4. This invention constructs a method for determining the thermal grade attributes of fluid channels by coupling the thermal phase fingerprint index with a baseline concentration value. By identifying ineffective cryogenic crossflow channels with high baseline concentration and low thermal fingerprint index, or effective combustion-driven oil displacement channels with high thermal fingerprint index, the number and contribution ratio of channels with different thermal grade attributes can be statistically analyzed. This quantitative evaluation result provides data support for gas injection parameter adjustment and profile control / water shut-off decisions in fire-driven development. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings are used to provide a further understanding of the present invention.

[0021] Figure 1 This is a schematic diagram of the framework in the embodiments of this application.

[0022] Figure 2 This is a flowchart illustrating an embodiment of this application. Detailed Implementation

[0023] The following is in conjunction with the appendix Figure 1 - Figure 2 A preferred description of the present invention is provided below.

[0024] See attached document Figure 1 - Figure 2 This invention proposes a composite high-temperature resistant tracer system for evaluating fire drive sweep efficiency, comprising the following modules: The composite tracer system injection module injects a composite tracer system containing an inert physical path reference tracer and a thermosensitive cascade reaction precursor tracer into the target reservoir to establish the initial state of underground fluid migration and thermochemical reactions. The produced fluid acquisition and detection module collects produced fluid samples from the production well, detects and obtains the baseline concentration value of the inert physical path baseline tracer, the first original concentration value of the first characteristic fingerprint product generated by the cracking of the thermal cascade reaction precursor tracer, and the second original concentration value of the second characteristic fingerprint product, and generates the original tracer response dataset. The physical transport model construction module calculates the physical retention coefficient and performs time series fitting based on the baseline concentration values ​​in the original tracer response dataset to generate a standardized physical transport model. The thermochemical production decoupling module calls the physical transport standardization model to perform physical attenuation reverse decoupling processing on the first and second original concentration values, generating a thermochemical evaluation dataset containing purification yield. The thermal phase fingerprint calculation module, based on the thermochemical evaluation dataset, calculates the ratio of the purification yield of the second characteristic fingerprint product to the purification yield of the first characteristic fingerprint product, and generates a thermal phase fingerprint index curve. The fire drive efficiency analysis report module couples the thermal phase fingerprint index curve with the baseline concentration value to determine the thermal level properties of the fluid channel and generate a fire drive sweep efficiency evaluation report.

[0025] In one embodiment of the present invention, the composite tracer system injection module is used to perform the following steps: A substance with a chemical decomposition initiation temperature higher than the preset maximum expected temperature of the combustion front is selected as an inert physical path reference tracer. A thermosensitive cascade reaction precursor tracer with staged thermal decomposition characteristics is synthesized, with a first thermosensitive bond and a second thermosensitive bond pre-placed in its molecular structure. The first thermosensitive bond breaks in the vapor zone temperature range to generate a first characteristic fingerprint product, and the second thermosensitive bond breaks in the core temperature range of the combustion front to generate a second characteristic fingerprint product. The inert physical path reference tracer and the thermosensitive cascade reaction precursor tracer are mixed to form a composite tracer system, which is then injected into the formation through an injection well. Forming the composite tracer system also includes: setting a preset mass ratio; calculating the required mass of each component based on the relationship that the total mass of the thermosensitive cascade reaction precursor tracer and the total mass of the inert physical path reference tracer satisfy the preset mass ratio; and using an automated injection control system to adjust the metering pump and deliver the two tracers to an online mixer for mixing according to the calculated required mass.

[0026] Specifically, firstly, based on the geological model parameters of the target reservoir, an inert physical path reference tracer is retrieved and selected from its built-in chemical property database. It should be noted that the inert physical path reference tracer should be a chemically highly stable compound, with a thermal decomposition temperature typically required to be above 500°C, to ensure that under the extreme thermal environment of formation fire flooding, i.e., above the highest expected temperature at the combustion front. Its chemical structure remains unchanged; in one embodiment of the invention, halogenated aromatic acid compounds, such as 2,6-difluorobenzoic acid, trifluoromethylbenzoic acid, or perfluoropentanoic acid, are typically selected. These substances have excellent water solubility and extremely high thermal stability, enabling them to accurately trace the physical transport pathways of aqueous fluids.

[0027] Once the inert physical pathway reference tracer is selected, the synthesis or formulation process of the thermosensitive cascade reaction precursor tracer is initiated. This process is based on molecular engineering design, coupling a first thermosensitive bond and a second thermosensitive bond with different thermal decomposition activation energies onto the same molecular backbone. The first thermosensitive bond is designed to operate within the vapor zone temperature range. Internal fractures generate the first characteristic fingerprint product; the second thermally sensitive bond is designed to exist only in the core temperature range of the combustion leading edge. The internal fracture of the first characteristic fingerprint product generates a second characteristic fingerprint product with a different structure. In this embodiment, the core feature of the thermosensitive cascade reaction precursor tracer is that its molecular structure contains at least two chemical bonds with clear dissociation energy barriers: the first thermosensitive bond is designed to break in the vapor zone temperature range of 150°C to 250°C, such as an aryl carboxylic acid ester bond, and the molecular fragments released after its breakage are rearranged or hydrolyzed to form a stable and easily detectable first characteristic fingerprint product; the second thermosensitive bond is designed to break only in the core temperature range of the combustion front above 350°C, such as a diaryl ether bond, and generates a second characteristic fingerprint product that is significantly different from the first characteristic fingerprint product in terms of molecular weight or polarity.

[0028] After the preparation of the two tracers is completed, the automated injection control system injects the tracers according to the preset mass ratio. A metering pump connected to both the inert physical path reference tracer tank and the thermosensitive cascade reaction precursor tracer tank delivers specific masses of the two components to an online mixer. To precisely control the injected tracer components, the automated injection control system calculates the mass relationship between the two tracers based on the following formula: In the formula, This represents the preset mass ratio, a dimensionless parameter, and its value is typically set between 0.5 and 2.0. This range is based on the fact that the thermal tracer will decompose in the formation, and its product concentration will inevitably be lower than the injected concentration. To ensure that the pyrolysis products can still be detected by the instrument after dilution (i.e., above the limit of detection (LOD), typically 0.1 μg / L), it is usually necessary to appropriately increase the injected amount of precursor tracer. If... Too low a value, such as less than 0.5, may cause the high-temperature product signal to be submerged in background noise; too high a value, such as greater than 2.0, will increase costs and may cause column overload. Represents the total mass of the injected thermosensitive cascade reaction precursor tracer; This represents the total mass of the injected inert physical path reference tracer. The automated injection control system calculates and proportions the total injection mass and preset mass ratio based on the total injection mass set in the work instruction. and The specific value.

[0029] Inside the mixer, the two tracers are thoroughly mixed with the main injection fluid, such as water or nitrogen, to form a homogeneous composite tracer system. Finally, the injection valve is opened, and the composite tracer system is injected into the target reservoir formation through an injection well using a high-pressure injection pump, thereby establishing the initial state of the subsurface tracer.

[0030] For example, suppose the target reservoir combustion front temperature for a field operation is expected to be 450°C, and the vapor zone temperature is 200°C. First, 2,6-difluorobenzoic acid is selected from the material library as an inert physical path baseline tracer, whose thermal decomposition temperature exceeds 550°C, meeting the stability requirements. Next, a specially synthesized compound, 4-phenoxyphenylacetic acid-4'-phenoxyphenyl ester, is selected as a precursor tracer for the thermosensitive cascade reaction. The ester bond in this molecule acts as the first thermosensitive bond, hydrolyzing and breaking at approximately 200°C to generate phenol and 4-phenoxyphenylacetic acid as the first characteristic fingerprint products; while the ether bonds in the diphenyl ether structure at both ends of the molecule act as the second thermosensitive bond, breaking at approximately 400°C to generate phenol and hydroquinone as the second characteristic fingerprint products. The operation instruction requires the injection of a tracer mixture with a total mass of 100 kg, and a preset mass ratio is set. The value is 1.5. Based on this, the automated injection control system calculates that precise metering from the storage tank is required. Thermosensitive cascade reaction precursor tracer and 2,6-Difluorobenzoic acid was then injected. Subsequently, these two materials were mixed with high-pressure injected water in a mixer, and the resulting composite tracer system was injected into the underground reservoir. After this stage, the formation initially contained 60 kg of the thermosensitive cascade reaction precursor tracer and 40 kg of 2,6-difluorobenzoic acid, while the initial concentrations of the first and second characteristic fingerprint products in the formation were zero, awaiting subsequent thermal field triggering.

[0031] In one embodiment of the present invention, a fluid acquisition and detection module is provided for performing the following steps: Fluid samples were collected at preset time intervals and pretreated by gas-liquid separation. Using chromatography-mass spectrometry, the inert physical path reference tracer, first characteristic fingerprint product, and second characteristic fingerprint product in the fluid samples were identified and quantified based on retention time and mass-to-charge ratio characteristics. The detected reference concentration values, first original concentration values, and second original concentration values ​​were correlated with the sampling time points to construct the original tracer response dataset.

[0032] Specifically, after the composite tracer system is injected into the formation, samples of the produced fluid are collected and processed. This system integrates a sampling valve controlled by a programmable logic controller (PLC), a gas-liquid-solid three-phase separator, and a sample storage unit. First, the PLC triggers the sampling valve to open at preset time intervals, such as every 6 hours, to collect a certain volume of produced fluid from the production well's main pipeline. It should be understood that the preset time interval is set based on the expected breakthrough time and fluid migration velocity of the reservoir, typically ranging from 4 to 24 hours. The setting is based on the following: for fire-driven reservoirs with a well spacing of less than 200 meters, the fluid velocity is high, requiring high-frequency sampling of 4-6 hours to capture concentration peaks; for reservoirs with large well spacing or low permeability, the fluid migration cycle is long, and the interval can be relaxed to 12-24 hours to control analysis costs.

[0033] The collected fluids were immediately pretreated in a gas-liquid-solid three-phase separator, where gases were vented, crude oil and solid particles were separated, and only the aqueous phase or a designated liquid phase sample was transferred to sealed sample vials with timestamps. These sequential samples were then sent to an analytical laboratory. In the laboratory, each sample was analyzed using a high-sensitivity gas chromatography-mass spectrometry (GC-MS) system equipped with an autosampler. GC-MS is a technique capable of qualitative and quantitative analysis of trace components in complex mixtures. This protocol utilizes its high selectivity and sensitivity to ensure effective detection of tracers and their products at concentrations as low as μg / L.

[0034] During the analysis, the sample, after extraction and concentration, is injected into a chromatographic column for separation based on the differences in boiling points and polarities of different compounds. The separated components are then sequentially introduced into a mass spectrometer. By comparing the mass spectra with those in a standard library, the inert physical pathway baseline tracer, the first characteristic fingerprint product, and the second characteristic fingerprint product are accurately identified, and their instantaneous concentrations are calculated. Specifically, the baseline concentration of the inert physical pathway baseline tracer, the first original concentration of the first characteristic fingerprint product, and the second original concentration of the second characteristic fingerprint product are recorded. The baseline concentration, the first original concentration, and the second original concentration refer to the mass concentration of each corresponding substance detected in the produced fluid sample at a specific sampling time t, with units of μg / L. Finally, the data acquisition and processing module correlates the analytical results of all samples with their corresponding sampling time points, arranging these data points chronologically to construct a structured raw tracer response dataset. This dataset is a time-series database, and its data structure includes at least four fields: timestamp, baseline concentration, first original concentration, and second original concentration, comprehensively recording the changes in the concentration of each component over time.

[0035] For example, 35 days after the injection of the composite tracer system, the automated online monitoring system located at the production wellhead collected the first produced fluid sample of the day at 10:00 AM. This sample was timestamped "Day 35, 10:00" and sent to the laboratory. Analysts used gas chromatography-mass spectrometry (GC-MS) to analyze the aqueous phase of the sample. For highly polar acid tracers, routine methylation derivatization can be performed before analysis to improve GC resolution. First, by using retention time and characteristic mass-to-charge ratio (m / z = 158), the inert physical pathway baseline tracer, 2,6-difluorobenzoic acid, was identified and quantified. Its calculated concentration was 12.8 μg / L, which is the baseline concentration value at that time. Next, a characteristic peak with a mass-to-charge ratio of m / z = 214 was detected at another retention time, confirming it as the first characteristic fingerprint product, 4-phenoxyphenylacetic acid, with a calculated concentration of 7.5 μg / L, which is the first initial concentration value. Simultaneously, a characteristic peak with a mass-to-charge ratio (m / z) of 110 was detected, corresponding to the second characteristic fingerprint product, hydroquinone, whose concentration was calculated to be 1.9 μg / L, which is the second original concentration value. The data acquisition and processing module recorded this set of data into the original tracer response dataset, forming a record: {timestamp: "Day35, 10:00", baseline concentration: 12.8, first original concentration: 7.5, second original concentration: 1.9}. At 16:00 on the same day, this process was repeated, with sampling and analysis performed again, generating another record: {timestamp: "Day35, 16:00", baseline concentration: 13.5, first original concentration: 8.1, second original concentration: 2.2}. Through this continuous sampling and analysis, the original tracer response dataset was continuously filled, forming multiple curves showing the concentration changing over time.

[0036] In one embodiment of the present invention, the physical transmission model construction module is used to perform the following steps: The initial total injected mass of the inert physical path reference tracer and the formation pore volume parameters of the target reservoir are obtained; the reference concentration value at each sampling time is extracted, the product of the reference concentration value and the formation pore volume parameter is calculated, and the product is divided by the initial total injected mass to obtain the physical retention coefficient at that sampling time; the physical retention coefficient at different sampling times is fitted by a numerical regression algorithm to establish a functional relationship describing the continuous change of the physical retention coefficient with time, which serves as a physical transport standardization model.

[0037] Specifically, this step is automatically executed by a data analysis and modeling system deployed in the cloud or on a local server. The system first calls the raw tracer response dataset stored in the database via an application programming interface (API). From this dataset, it extracts two-dimensional time-series data consisting of sampling timestamps and baseline concentration values. This sequence visually reflects the concentration response curve of the inert physical path baseline tracer in the production well.

[0038] Next, two key prior parameters are retrieved from the project configuration file or the associated geological information database: the initial total mass of the inert physical path baseline tracer recorded during the injection operation. and formation pore volume parameters characterizing the interwell fluid space. The formation pore volume parameter represents the total effective underground pore space capable of participating in fluid flow. This parameter is typically given by reservoir geologists through analysis of well logging data and core samples, and its typical value range varies from 10 to 10 depending on the reservoir size. 4 m 3 Up to 10 6 m 3 between.

[0039] For each data point in the baseline concentration time series, the data analysis and modeling system performs a normalization calculation to determine the physical retention coefficient at that sampling time. The physical retention coefficient is calculated according to the following formula: In the formula, Let be the physical retention coefficient at time t; The baseline concentration value detected in the sample collected at time t; Formation pore volume parameters; This represents the initial total injected mass. The physical meaning of this calculation lies in restoring the instantaneous production concentration to the mass fraction of the tracer within the formation pore volume. It should be noted that the physical retention coefficient is a dimensionless parameter ranging from 0 to 1. It quantitatively characterizes the degree of signal intensity attenuation caused by the adsorption of tracer particles injected from the injection well to the production well, due to adsorption by formation rocks, hydrodynamic dispersion in porous media, and mixing and dilution with existing formation fluids. A higher physical retention coefficient value indicates a fluid channel with higher physical transport efficiency.

[0040] After calculating the physical retention coefficients for all sampling times, these coefficient values ​​are combined with their corresponding timestamps to form a new time series. Finally, a pre-defined numerical fitting algorithm, such as least squares, cubic spline interpolation, or Gaussian process regression, is applied to process this new time series, fitting a mathematical curve or function that describes the continuous change of the physical retention coefficients over time. This mathematical function is then defined and stored as a physical transport normalization model, which is essentially a time function. The physical transport characteristics of fluids in the dominant channels between wells were solidified through mathematical forms, providing a quantitative physical attenuation benchmark for the concentration correction of chemical reaction products in subsequent steps.

[0041] For example, following the preceding steps, the data analysis and modeling system begins processing the raw tracer response dataset. Data points from "Day 35, 10:00" are extracted, with a baseline concentration of 12.8 μg / L. First, unit conversion is performed, converting 12.8 μg / L to... kg / m³. Simultaneously, the initial total injected mass of the inert physical path reference tracer was retrieved from the injection record. The weight is 40 kg, and the formation pore volume parameters between wells are obtained from the geological model database. The value is 50,000 m³. Next, these values ​​are substituted into the formula to calculate the physical retention coefficient at that moment: Similarly, for the sample at 16:00, the baseline concentration was 13.5 μg / L, i.e. kg / m³, the physical retention coefficient at that moment was calculated to be After calculating the physical retention coefficients for all sampling points within the monitoring period, these coefficient values, such as 0.016 and 0.016875, are combined with their respective time points to form a dataset. A cubic polynomial is then applied to this dataset to generate a physical transport normalization model, which is a function of time t, for example... .

[0042] In one embodiment of the present invention, the thermochemical generation decoupling module is used to perform the following steps: Substitute the sampling time point into the physical transport normalization model to calculate the physical retention coefficient for correction at that time. Divide the first original concentration value by the physical retention coefficient for correction to obtain the purification yield of the first characteristic fingerprint product. Divide the second original concentration value by the physical retention coefficient for correction to obtain the purification yield of the second characteristic fingerprint product. Store the purification yields of the first and second characteristic fingerprint products calculated at each time point in a time series to generate a thermochemical evaluation dataset.

[0043] Specifically, after generating the physical transport standardization model in the aforementioned steps, the data analysis and modeling system continues to execute to complete the reverse decoupling process of physical attenuation of the original concentration data. The core idea of ​​the so-called reverse decoupling process of physical attenuation is to use a known physical process model to reverse-engineer the signal components contributed purely by chemical processes from the observed signal, which includes the combined effects of physical and chemical processes.

[0044] First, the first and second original concentration values ​​corresponding to each sampling time point t are read sequentially from the original tracer response dataset. For each time point t, the time value t is substituted into the established physical transport normalization model function to calculate the precise physical retention coefficient value at that moment. Then, the physical transport normalization model is used as an inverse correction operator to process the original concentration values. The purification yield is calculated based on the following formula: In the formula, It is the purification yield of the first characteristic fingerprint product at time t. It is the first raw concentration value detected at time t. It is the physical retention factor at time t, calculated by the physical transport normalization model. Similarly, It is the purification yield of the second characteristic fingerprint product at time t. This is the second original concentration value detected at time t. Due to the physical retention coefficient... Dimensionless, therefore the unit of purification yield is consistent with the unit of the original concentration value. In a physical sense, this index represents the theoretical concentration of the product in the injected fluid, assuming no physical dilution and formation adsorption, produced solely by thermochemical reactions.

[0045] Specifically, the first original concentration value at time point t is divided by the corresponding physical retention coefficient value; this quotient is defined as the purification yield of the first characteristic fingerprint product. Similarly, the second original concentration value is divided by the physical retention coefficient value at the same time point to obtain the purification yield of the second characteristic fingerprint product. This division operation compensates for signal loss caused by physical adsorption, dilution, and diffusion during fluid migration underground, thus restoring the true generation intensity of the chemical reaction in the formation thermal field. The calculated purification yield is a key derived parameter; it characterizes the equivalent concentration of characteristic fingerprint products generated per unit volume of fluid after experiencing the formation thermal field, after excluding all physical transport attenuation effects. Its units are consistent with the units of the original concentration values.

[0046] This calculation process is repeated for all time points in the original tracer response dataset to generate a complete time series consisting of a series of timestamps and two corresponding purification yields. Finally, this time series is stored as a new data structure, namely the thermochemical evaluation dataset, which is a two-dimensional time series array containing three fields: sampling timestamp, purification yield of the first characteristic fingerprint product, and purification yield of the second characteristic fingerprint product. This dataset eliminates the interference of physical transport processes, providing an accurate data foundation for subsequent steps of pure thermal field structure analysis.

[0047] For example, the data analysis and modeling system begins processing the sample data collected at "Day 35, 10:00". The first raw concentration value at that time is read from the original tracer response dataset as 7.5 μg / L, and the second raw concentration value is 1.9 μg / L. Simultaneously, using the established physical transport normalization model, the physical retention coefficient at that time is found to be 0.016. Subsequently, an inverse decoupling calculation is performed, dividing the first raw concentration value by the physical retention coefficient to obtain the purification yield of the first characteristic fingerprint product, calculated as 7.5 / 0.016 = 468.75 μg / L. Then, the purification yield of the second characteristic fingerprint product is calculated using the same method, calculated as 1.9 / 0.016 = 118.75 μg / L. Finally, this set of calculation results is stored in the thermochemical evaluation dataset, forming a record: {timestamp: "Day35, 10:00", net yield_1: 468.75, net yield_2: 118.75}. This process is performed sequentially on all sampled data points, thereby transforming the original concentration curve, which is distorted by physical effects, into a net yield curve that can truly reflect the intensity of underground thermochemical reactions.

[0048] In one embodiment of the present invention, the thermal fingerprint calculation module is used to perform the following steps: The purification yields of the second and first characteristic fingerprint products at the same sampling time are extracted from the thermochemical evaluation dataset. The dimensionless ratio of the purification yield of the second to the first characteristic fingerprint product is calculated, and this ratio is defined as the thermal phase fingerprint index at that time. The calculated thermal phase fingerprint indices are arranged in chronological order, and a thermal phase fingerprint index curve is plotted. The calculation of the dimensionless ratio also includes: determining whether the purification yield of the first characteristic fingerprint product is lower than a preset signal-to-noise ratio threshold; if so, the thermal phase fingerprint index is directly set to a preset saturation upper limit value; if not, the operation of calculating the dimensionless ratio of the purification yield of the second to the first characteristic fingerprint product is performed.

[0049] Specifically, after generating the thermochemical evaluation dataset in the aforementioned steps, key indicators characterizing the thermal field intensity are calculated and constructed. The thermochemical evaluation dataset is processed record by record. For each sampling time t in the dataset, the purification yield of the second characteristic fingerprint product and the purification yield of the first characteristic fingerprint product at that time are extracted simultaneously.

[0050] Subsequently, the core differential ratio calculation is performed, which involves dividing the purification yield of the second characteristic fingerprint product by the purification yield of the first characteristic fingerprint product. The calculation formula is as follows: In the formula, This represents the thermal phase fingerprint index at time t, and its value is dimensionless. The purification yield of the second characteristic fingerprint product calculated at time t; Let be the purification yield of the first characteristic fingerprint product calculated at time t. In specific engineering implementations, to avoid the calculation results diverging due to the denominator approaching zero caused by detection noise, a signal-to-noise ratio threshold is set. When the purification yield of the first characteristic fingerprint product is lower than this threshold, the ratio is assigned a preset upper limit value for saturation, which is used to characterize the extreme case where the fluid flows almost completely through the core region of the combustion front.

[0051] Thermal fingerprint index This is the core evaluation index proposed in this invention, and its physical significance lies in quantifying the highest temperature journey experienced by the fluid micro-element. A higher index value indicates that the fluid flows more through the combustion front core region, for example, greater than 1, resulting in the generation of more secondary characteristic fingerprint products; while a lower index value indicates that the fluid mainly flows through the lower temperature vapor zone, for example, close to 0, triggering only the first-stage pyrolysis reaction. This dimensionless ratio calculation characteristic makes the results independent of fluctuations in the total fluid recovery, thus more purely reflecting the generation ratio relationship between the two chemical reaction products.

[0052] This calculation process is applied to all time points in the thermochemical evaluation dataset to generate a corresponding thermal phase fingerprint index for each time point. Finally, all calculated thermal phase fingerprint indices are combined with their corresponding timestamps to generate a single time series, which is the thermal phase fingerprint index curve. Plotting time on the x-axis and the thermal phase fingerprint index on the y-axis, it visually displays the dynamic changes in the thermal history of the fluid reaching the production well over time. The peaks and troughs of the curve correspond to the fluid dominance breakthroughs in the high-temperature combustion channel and the low-temperature steam channel, respectively.

[0053] For example, following the preceding steps, the data analysis and modeling system continues processing the data from "Day 35, 10:00". The purification yield of the first characteristic fingerprint product at that time is retrieved from the thermochemical evaluation dataset. The purification yield of the second characteristic fingerprint product was 468.75 μg / L. The concentration was 118.75 μg / L. Next, these two values ​​were substituted into the formula to calculate the thermal fingerprint index at that moment. The calculation process is as follows: Therefore, at "Day 35, 10:00", the thermal phase fingerprint index value is 0.2533. This value indicates that the fluid inclusions arriving at the production well at this moment experienced the effects of both the steam zone and the combustion front on their migration path, but the influence of the steam zone was dominant in the composition of pyrolysis products. This calculation result was recorded as a data point {timestamp: "Day 35, 10:00", thermal phase fingerprint index: 0.2533}. By performing the same calculation on all purification yield data pairs throughout the entire monitoring period, a complete thermal phase fingerprint index curve was finally constructed for subsequent fire drive sweep efficiency analysis.

[0054] In one embodiment of the present invention, the fire-drive efficiency analysis report module is used to perform the following operations: The system sets high-temperature combustion threshold, low-temperature steam threshold, and crossflow judgment concentration threshold. If the thermal phase fingerprint index is higher than the high-temperature combustion threshold, the current moment is determined to be an effective combustion-driven oil displacement channel. If the thermal phase fingerprint index is between the high-temperature combustion threshold and the low-temperature steam threshold, the current moment is determined to be the steam-dominated stage. If the thermal phase fingerprint index is lower than the low-temperature steam threshold, and the corresponding baseline concentration value is higher than the crossflow judgment concentration threshold, the current moment is determined to be an ineffective low-temperature crossflow channel. The distribution of thermal grade attributes of each fluid channel is statistically analyzed to generate a fire-driven sweep efficiency evaluation report. The steps for generating the fire-driven sweep efficiency evaluation report also include: statistically analyzing the duration or cumulative fluid flux percentage of effective combustion-driven oil displacement channels, steam-dominated stages, and ineffective low-temperature crossflow channels during the monitoring period; for areas determined to be ineffective low-temperature crossflow channels, fire-driven development adjustment strategies including gas injection rate adjustments or selective water shut-off operations are formulated and written into the fire-driven sweep efficiency evaluation report.

[0055] Specifically, the final step of the method of this invention is automatically executed by the data analysis and modeling system to complete the comprehensive judgment of the fire-driven sweep efficiency and generate decision support. First, two preset threshold parameters are loaded from its internal storage: a high-temperature combustion threshold and a low-temperature steam threshold. The high-temperature combustion threshold is a dimensionless value preset based on laboratory pyrolysis experiments and reservoir numerical simulations, ranging from 0.8 to 1.5, preferably 0.9. This threshold is set based on the fact that, under laboratory conditions, when the tracer is completely exposed to an environment above 400°C, the generation ratio of the second characteristic fingerprint product to the first characteristic fingerprint product is typically stable at around 1.0. The low-temperature steam threshold is also a preset dimensionless value, ranging from 0.05 to 0.2, preferably 0.1. This threshold is set based on the fact that, in experiments with only 200°C steam displacement, the second characteristic product is almost not generated, and the ratio caused by background noise is typically below 0.1.

[0056] Subsequently, the generated thermal phase fingerprint index curve and the baseline concentration value time series from the generated original tracer response dataset are simultaneously invoked. These two time series are synchronously traversed, and coupled analysis is performed on the data points at each sampling time t. For a given time t, the value of the thermal phase fingerprint index is first compared with the high-temperature combustion threshold and the low-temperature steam threshold. If the index is higher than the high-temperature combustion threshold, this time is marked as the combustion zone dominance stage. This corresponds to an effective combustion-driven oil displacement channel, meaning the fluid path successfully crosses the high-temperature combustion front, achieving effective coupling between heat and the displacement fluid. If the index is between the two thresholds, it is marked as the steam zone dominance stage.

[0057] Specifically, when the thermal phase fingerprint index is below the cryogenic steam threshold, the baseline concentration value at that moment is further read. If the baseline concentration value is higher than the preset crossflow judgment concentration threshold, the fluid at this moment is determined to originate from an invalid cryogenic crossflow channel and is marked as a cold fluid bypass stage. An invalid cryogenic crossflow channel refers to a high-permeability path in the formation that allows the injected fluid to bypass the main heating zone and flow directly and rapidly to the production well. Its characteristics include rapid tracer recovery, high concentration, but no effective heat information. The crossflow judgment concentration threshold is usually set to 10%–20% of the peak concentration of the inert tracer, for example, 10.0 μg / L, to exclude normal low-concentration dispersion tailing phenomena. By classifying the data throughout the monitoring period as described above, a thermal level attribute is assigned to each time point.

[0058] After determining all time points, statistical analysis is performed on the duration or cumulative fluid flux of various thermal grade attribute markers to calculate the proportions of the combustion zone-dominated stage, the steam zone-dominated stage, and the cold fluid bypass stage. Finally, based on these statistical results, a fire-driven sweep efficiency evaluation report is automatically generated using a built-in expert rule base. This report includes a quantitative assessment of sweep efficiency, thermal grade attribute distribution maps for each channel, and specific suggestions for optimizing injection parameters.

[0059] For example, the data analysis and modeling system begins executing the final judgment process. It loads the set high-temperature combustion threshold of 0.9, low-temperature steam threshold of 0.1, and cross-flow judgment concentration threshold of 10.0 μg / L from the configuration library. First, it analyzes the data at "Day 35, 10:00," where the thermal phase fingerprint index is 0.2533. Since 0.1 < 0.2533 < 0.9, this time point is classified as the steam-dominated stage. Next, it analyzes the data at another time, "Day 42, 14:00," where the detected baseline concentration is 15.0 μg / L, and the calculated thermal phase fingerprint index is 0.08. Because the baseline concentration of 15.0 μg / L is higher than the cross-flow judgment concentration threshold of 10.0 μg / L, and the thermal phase fingerprint index of 0.08 is lower than the low-temperature steam threshold of 0.1, it is determined that the fluid at this time originates from an invalid low-temperature cross-flow channel. Further analysis of the data at "Day 55, 18:00" revealed a thermal phase fingerprint index of 1.2, exceeding the high-temperature combustion threshold of 0.9. Therefore, this time was determined to be dominated by an effective combustion-driven oil displacement channel. After classifying the data for the entire monitoring period, statistics showed that ineffective low-temperature crossflow channels contributed 45% of the production, the steam zone contributed 40%, while effective combustion-driven oil displacement channels contributed only 15%. Based on these results, the generated fire-driven sweep efficiency evaluation report clearly stated: "The current fire-driven scheme suffers from severe fluid crossflow problems and low heat utilization." The report further recommended optimizing the gas injection parameters: "It is recommended to reduce the current gas injection rate of 10,000 m³ / d by 15% and to selectively shut off water in the injection wells to block the dominant crossflow channels and improve heat sweep efficiency."

[0060] Each of the modules can be implemented in whole or in part through software, hardware, or a combination thereof. It supports hardware embedded in or independent of the processor in the computer device, and also supports software stored in the memory of the computer device, so that the processor can call and execute the operations corresponding to each of the above modules.

[0061] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. 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 of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A composite high-temperature resistant tracer system for evaluating fire drive sweep efficiency, characterized in that, include: The composite tracer system injection module injects a composite tracer system containing an inert physical path reference tracer and a thermosensitive cascade reaction precursor tracer into the target reservoir to establish the initial state of underground fluid migration and thermochemical reactions. Specifically, this includes: selecting substances with a chemical decomposition initiation temperature higher than the preset highest expected temperature of the combustion front as inert physical path reference tracers; synthesizing a thermosensitive cascade reaction precursor tracer with staged thermal decomposition characteristics, pre-positioning a first thermosensitive bond and a second thermosensitive bond in the molecular structure, wherein the first thermosensitive bond breaks in the vapor zone temperature range to generate a first characteristic fingerprint product, and the second thermosensitive bond breaks in the core temperature range of the combustion front to generate a second characteristic fingerprint product; mixing the inert physical path reference tracer and the thermosensitive cascade reaction precursor tracer to form a composite tracer system, and injecting it into the formation through an injection well; The produced fluid acquisition and detection module collects produced fluid samples from the production well, detects and obtains the baseline concentration value of the inert physical path baseline tracer, the first original concentration value of the first characteristic fingerprint product generated by the cracking of the thermal cascade reaction precursor tracer, and the second original concentration value of the second characteristic fingerprint product, and generates the original tracer response dataset. The physical transport model construction module calculates the physical retention coefficient and performs time series fitting based on the baseline concentration values ​​in the original tracer response dataset to generate a physical transport standardized model. Specifically, this includes: obtaining the initial total injected mass of the inert physical path baseline tracer and the formation pore volume parameters of the target reservoir; extracting the baseline concentration value at each sampling time point, calculating the product of the baseline concentration value and the formation pore volume parameters, and dividing this product by the initial total injected mass to obtain the physical retention coefficient at that sampling time point; applying a numerical regression algorithm to fit the physical retention coefficients at different sampling time points, establishing a functional relationship describing the continuous change of the physical retention coefficient over time, which serves as the physical transport standardized model. The thermochemical generation decoupling module calls the physical transport normalization model to perform reverse decoupling processing on the first and second original concentration values ​​to achieve physical attenuation, generating a thermochemical evaluation dataset containing purification yields. Specifically, this includes: substituting the sampling time point into the physical transport normalization model to calculate the correction physical retention coefficient for that sampling time point; dividing the first original concentration value by the correction physical retention coefficient to obtain the purification yield of the first characteristic fingerprint product; dividing the second original concentration value by the correction physical retention coefficient to obtain the purification yield of the second characteristic fingerprint product; and storing the purification yields of the first and second characteristic fingerprint products calculated at each sampling time point in a time series to generate a thermochemical evaluation dataset. The thermal phase fingerprint calculation module, based on the thermochemical evaluation dataset, calculates the ratio of the purification yield of the second characteristic fingerprint product to the purification yield of the first characteristic fingerprint product, and generates a thermal phase fingerprint index curve. The fire drive efficiency analysis report module couples the thermal phase fingerprint index curve with the baseline concentration value to determine the thermal level properties of the fluid channel and generate a fire drive sweep efficiency evaluation report.

2. The composite high-temperature resistant tracer system for evaluating fire drive sweep efficiency according to claim 1, characterized in that, The output fluid acquisition and detection module is used to perform the following operations: Collect output fluid samples at preset time intervals and perform gas-liquid separation pretreatment on the samples; Using chromatography-mass spectrometry (GC-MS) analysis, based on retention time and mass-to-charge ratio characteristics, inert physical pathway reference tracers, first characteristic fingerprint products, and second characteristic fingerprint products in fluid samples are identified and quantified. The detected baseline concentration value, the first original concentration value, and the second original concentration value are correlated with the sampling time point to construct the original tracer response dataset.

3. The composite high-temperature resistant tracer system for evaluating fire drive sweep efficiency according to claim 1, characterized in that, The thermal fingerprint calculation module is used to perform the following steps: The purification yield of the second characteristic fingerprint product and the purification yield of the first characteristic fingerprint product at the same sampling time point were extracted from the thermochemical evaluation dataset. Calculate the dimensionless ratio of the purification yield of the second characteristic fingerprint product to the purification yield of the first characteristic fingerprint product, and define this ratio as the thermal phase fingerprint index at the sampling time point. Arrange the calculated thermal phase fingerprint indices in chronological order and plot the generated thermal phase fingerprint index curve.

4. The composite high-temperature resistant tracer system for evaluating fire drive sweep efficiency according to claim 1, characterized in that, The fire-drive efficiency analysis report module is used to perform the following operations: Set high-temperature combustion threshold, low-temperature steam threshold, and cross-flow judgment concentration threshold; If the thermal phase fingerprint index is higher than the high-temperature combustion threshold, the current sampling time point is determined to be an effective combustion-driven oil passage; if the thermal phase fingerprint index is between the high-temperature combustion threshold and the low-temperature steam threshold, the current sampling time point is determined to be the steam-dominated stage. If the thermal phase fingerprint index is lower than the low-temperature steam threshold and the corresponding baseline concentration value is higher than the crossflow judgment concentration threshold, the current sampling time point is determined to be an invalid low-temperature crossflow channel. The distribution of thermal properties of each fluid channel is statistically analyzed to generate a fire drive sweep efficiency evaluation report.

5. A composite high-temperature resistant tracer system for evaluating fire drive sweep efficiency according to claim 1, characterized in that, The formation of a composite tracer system also includes: Set the preset mass ratio; Based on the relationship that the total mass of the thermal cascade reaction precursor tracer and the total mass of the inert physical path reference tracer satisfy a preset mass ratio, the required mass of each component is calculated. An automated injection control system is used to regulate the metering pump, delivering the two tracers to an online mixer for mixing according to the calculated required mass.

6. A composite high-temperature resistant tracer system for evaluating fire drive sweep efficiency according to claim 3, characterized in that, Calculating dimensionless ratios also includes: Determine whether the purification yield of the first feature fingerprint product is lower than the preset signal-to-noise ratio threshold; If so, the thermal fingerprint index will be directly set to the preset saturation upper limit value; If not, then perform the operation of calculating the dimensionless ratio of the purification yield of the second characteristic fingerprint product to the purification yield of the first characteristic fingerprint product.

7. A composite high-temperature resistant tracer system for evaluating fire drive sweep efficiency according to claim 1, characterized in that, The generation of the fire drive sweep efficiency evaluation report also includes: The duration or cumulative fluid flux of the effective combustion-driven oil flow channel, the steam zone-dominated stage, and the ineffective low-temperature crossflow channel during the monitoring period was statistically analyzed. For areas identified as ineffective cryogenic crossflow channels, develop fire-drive development adjustment strategies that include adjusting the gas injection rate or selective water shut-off operations, and include these strategies in the fire-drive spillover efficiency evaluation report.

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