Method for measuring oil content of oil-based drilling cuttings and application thereof

Abstract

The application relates to the technical field of oil content measurement, in particular to an oil content measurement method of oil-based drilling cuttings and application thereof. First, a dynamic extraction curve database is inquired according to sample lithology and a treatment method, an optimal extraction time point is determined by calculating a concentration change rate; in the extraction process, multi-point sampling is carried out, the environmental temperature and pressure are measured, an environmental influence model containing a temperature influence sub-model and a pressure influence sub-model is established, and an environmental correction factor is obtained; infrared spectrum measurement is carried out on the extraction liquid sample, data correction is carried out, the average value and the standard deviation are calculated, and abnormal values are removed; finally, a segmented linear equation for different concentration ranges is used to calculate the final oil content; by considering the lithology characteristics, the environmental influence and the segmented linear relationship, the measurement accuracy and reliability are significantly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil content measurement, and in particular to an oil-based drilling cuttings oil content measurement method and application thereof. BACKGROUND

[0002] With the development of oil drilling technology, oil-based drilling fluid is increasingly widely used in drilling operations. Oil-based drilling fluid has good inhibition, lubricity and carrying capacity, but the generated oil-based drilling cuttings contain a large amount of oil, which can cause serious environmental pollution if not properly treated. Therefore, accurately measuring the oil content of oil-based drilling cuttings is of great significance for evaluating the treatment effect and environmental risk.

[0003] At present, infrared spectroscopy has become one of the main methods for measuring the oil content of oil-based drilling cuttings due to its rapid and simple characteristics. This method measures the absorbance of the extract at the characteristic absorption wavelength of hydrocarbons, establishes a linear equation for oil content calculation, and is widely used in industrial applications.

[0004] However, the existing extraction process lacks specificity, and the measurement results are easily affected by external conditions, resulting in measurement errors and affecting the measurement accuracy. This situation needs to be further improved. SUMMARY

[0005] To solve the problem of the existing oil content measurement method that the extraction process lacks specificity, the measurement results are easily affected by external conditions, resulting in measurement errors and affecting the measurement accuracy, the present application provides an oil-based drilling cuttings oil content measurement method and application thereof, which adopts the following technical solution:

[0006] In a first aspect, the present application provides an oil-based drilling cuttings oil content measurement method, comprising the following steps:

[0007] Obtain the lithology type and treatment method of the sample, and determine the optimal extraction time point according to the dynamic extraction curve corresponding to the lithology type and treatment method;

[0008] Within the optimal extraction time, take multiple samples at a predetermined time interval to obtain extract samples at multiple time points;

[0009] Measure the ambient temperature and pressure, input the ambient temperature and pressure into a predetermined environmental influence model to obtain an environmental correction factor;

[0010] Measure the infrared spectrum of each of the multiple extract samples to obtain an absorbance data sequence, and correct the absorbance data according to the environmental correction factor;

[0011] Calculate the mean and standard deviation according to the corrected absorbance data sequence, and obtain the effective measurement result after removing the abnormal value;

[0012] substituting the effective measurement result into a pre-established segmented working curve to obtain the final oil content, wherein the segmented working curve comprises linear equations of different concentration ranges.

[0013] By adopting the technical scheme, in actual operation, different rock types of drill cuttings samples often require different extraction times, and fluctuations in environmental temperature and pressure can affect the accuracy of measurement results. The application first queries a dynamic extraction curve database according to the sample lithology and processing method, determines the optimal extraction time point by calculating the concentration change rate; multi-point sampling is performed during the extraction process, and the environmental temperature and pressure are measured simultaneously, an environmental influence model including a temperature influence sub-model and a pressure influence sub-model is established, and an environmental correction factor is obtained; the extractant sample is measured by infrared spectroscopy and the data is corrected, the average value and the standard deviation are calculated to eliminate abnormal values; finally, a segmented linear equation for different concentration ranges is used to calculate the final oil content; by considering the lithology characteristics, environmental influence and segmented linear relationship, the measurement accuracy and reliability are significantly improved.

[0014] Optionally, the lithology type and processing method of the sample are obtained, and the optimal extraction time point is determined according to the dynamic extraction curve corresponding to the lithology type and processing method, specifically including the following steps:

[0015] The lithology type of the sample is obtained, and the corresponding processing method is obtained by querying a pre-established lithology classification table according to the lithology type;

[0016] The corresponding dynamic extraction curve is obtained by querying a pre-established dynamic extraction curve database based on the processing method;

[0017] The average concentration change rate before and after each time point is calculated according to the dynamic extraction curve, and when the average concentration change rate is less than a preset threshold in a continuous time interval of a preset length, the starting time point of the continuous time interval is determined as the optimal extraction time point.

[0018] By adopting the technical scheme, in practice, different lithology of shale, sandstone and other drilling cuttings samples have different physical and chemical properties, and fixed extraction time often leads to insufficient extraction or over-extraction, for example, for dense lithology samples, conventional 15-minute extraction may not be sufficient for sufficient extraction, and for loose porous samples, too long extraction time will introduce other interfering substances; the application first determines the lithology of the collected oil-based drilling cuttings sample to obtain basic lithology information, including rock type, structural characteristics, etc.; then according to the lithology information, the pre-established lithology classification table is queried to obtain the corresponding processing method, such as broken particle size, extractant selection, etc.; then the dynamic extraction curve database is queried to obtain the standard dynamic extraction curve of the sample of this type; finally, by calculating the average concentration change rate in a continuous time interval, when the change rate is less than a set threshold in a certain time interval, the starting point of the interval is determined as the optimal extraction time point; the accurate control of the extraction time is realized, and the problems caused by the uniform setting of the extraction time in the traditional method are avoided.

[0019] Optionally, the ambient temperature and pressure are measured, and the ambient temperature and pressure are input into a preset ambient influence model to obtain an ambient correction factor, and the method comprises the following steps:

[0020] The temperature and pressure measurement values of the current environment are obtained;

[0021] The temperature and pressure measurement values are compared with the standard temperature and standard pressure respectively to obtain temperature deviation and pressure deviation;

[0022] The temperature correction coefficient and the pressure correction coefficient are calculated according to the temperature deviation and the pressure deviation through the preset ambient influence model, wherein the ambient influence model comprises a temperature influence sub-model and a pressure influence sub-model, the input parameters of the temperature influence sub-model comprise the temperature deviation and the sample moisture content, and the input parameters of the pressure influence sub-model comprise the pressure deviation and the sample density;

[0023] The temperature correction coefficient and the pressure correction coefficient are multiplied to obtain the ambient correction factor.

[0024] By adopting the technical scheme, the actual temperature and pressure measurement values of the field environment are first obtained, which are compared with the standard test conditions to calculate the temperature deviation and the pressure deviation; then the deviation values are input into the pre-established ambient influence model, which is divided into a temperature influence sub-model and a pressure influence sub-model, wherein the temperature influence sub-model not only considers the temperature deviation, but also takes the sample moisture content as an important parameter, and the pressure influence sub-model calculates in combination with the pressure deviation and the sample density; finally, the temperature correction coefficient and the pressure correction coefficient are multiplied to obtain the comprehensive ambient correction factor; the coupling effect of the temperature, pressure and other environmental factors and the physical properties of the sample is considered, so that the measurement result is more accurate and reliable.

[0025] Optionally, according to the temperature deviation and the pressure deviation, a temperature correction coefficient and a pressure correction coefficient are calculated through a preset environmental influence model, and the method comprises the following steps:

[0026] The moisture content and the density of the sample are measured;

[0027] The temperature deviation and the moisture content of the sample are input into a temperature influence sub-model to obtain the temperature correction coefficient under different moisture contents;

[0028] The pressure deviation and the density of the sample are input into a pressure influence sub-model to obtain the pressure correction coefficient under different densities;

[0029] When the moisture content of the sample is greater than a preset threshold, the temperature correction coefficient is weightedly corrected; and when the density of the sample is greater than a preset threshold, the pressure correction coefficient is weightedly corrected.

[0030] By using the above technical solution, the moisture content and the density of the sample are measured first to obtain basic physical characteristic parameters; then the temperature deviation and the moisture content of the sample are input into a temperature influence sub-model to obtain the temperature correction coefficient under different moisture contents, and the pressure deviation and the density of the sample are input into a pressure influence sub-model to obtain the pressure correction coefficient under different densities; when the moisture content of the sample exceeds a preset threshold, the temperature correction coefficient is weightedly corrected to reflect the sensitive characteristic of the high-moisture-content sample to the temperature change; similarly, when the density of the sample exceeds a preset threshold, the pressure correction coefficient is also weightedly corrected accordingly; by using the threshold judgment and the weighted correction mechanism, the dynamic adjustment of the correction coefficient according to the sample characteristics is realized, the pertinence and the accuracy of the environmental correction are improved, and the measurement result is more reliable.

[0031] Optionally, the absorbance data are corrected according to the environmental correction factor, and the method comprises the following steps:

[0032] The absorbance data of a plurality of characteristic peaks in the absorption region of the hydrocarbon characteristic functional group of the extract liquid sample are obtained;

[0033] The absorbance deviation of each characteristic peak under the influence of the environment is calculated according to the environmental correction factor;

[0034] The absorbance deviation and the absorbance data of the corresponding characteristic peak are corrected to obtain the corrected characteristic peak absorbance value;

[0035] The corrected characteristic peak absorbance value is normalized according to the concentration of the extract liquid to obtain the final correction result.

[0036] By adopting the technical scheme, firstly, a plurality of characteristic absorption peaks are selected in a hydrocarbon characteristic functional group absorption region, and absorbance data are obtained, including different types of absorption such as C-H stretching vibration and C-H bending vibration; then, the obtained environmental correction factor is used to calculate the absorbance deviation amount possibly generated by each characteristic peak under the current environmental condition; then, the original absorbance data of each characteristic peak are corrected and calculated to eliminate the measurement error caused by the environment; finally, considering the range difference of the absorbance data of different concentration samples, a normalization processing method is adopted to make the correction result have better comparability, and the reliability and accuracy of the measurement are improved.

[0037] Optionally, the effective measurement result is substituted into a pre-established segmented working curve to obtain a final oil content, specifically including the following steps:

[0038] According to the numerical range of the effective measurement result, a corresponding concentration range interval is selected;

[0039] In the concentration range interval, corresponding linear equation parameters are obtained;

[0040] The effective measurement result is substituted into the selected linear equation to calculate a preliminary oil content;

[0041] According to the mass of the sample and the volume of the extractant, the preliminary oil content is volume-corrected to obtain a final oil content.

[0042] By adopting the technical scheme, firstly, according to the corrected effective measurement result, a concentration range interval to which the effective measurement result belongs is determined, and the intervals may include multiple levels such as low concentration, medium concentration and high concentration; then, in the determined concentration interval, linear equation parameters corresponding to the interval are called, and the parameters are obtained by a large number of standard sample tests and optimization; then, the effective measurement result is substituted into the selected linear equation to obtain a preliminary oil content value; finally, considering that the mass of the actual sample and the volume of the extractant used may be different from the standard condition, the preliminary oil content is corrected by a volume correction coefficient to obtain a final oil content result.

[0043] Optionally, in the concentration range interval, corresponding linear equation parameters are obtained, specifically including the following steps:

[0044] According to the concentration range interval, an absorbance and oil content data pair of a standard sample is obtained;

[0045] The absorbance and the oil content are linearly fitted to obtain slope and intercept parameters;

[0046] The fitting goodness of the standard sample in the corresponding interval is calculated, and when the fitting goodness is greater than a preset threshold, the slope and intercept parameters are determined to be valid;

[0047] The values of the slope and the intercept parameters meet preset interval limitation conditions for different concentration range intervals.

[0048] By adopting the technical solution, the standard sample in each concentration range interval is selected for measurement, a series of corresponding data pairs of absorbance and oil content are obtained, linear fitting analysis is performed on the data pairs, the slope and the intercept parameters specific to the interval are obtained, the goodness index of linear fitting, such as the correlation coefficient, is calculated, and the effectiveness of the parameter group is confirmed only when the goodness of fitting exceeds the preset threshold. Meanwhile, the value range of the slope and the intercept parameters is set to ensure the rationality and continuity of the parameters in different intervals. The parameter effectiveness judgment mechanism is adopted to ensure the calculation accuracy of each interval, and the parameter value limitation is adopted to ensure the smooth transition between different intervals, thereby improving the accuracy and reliability of the oil content calculation.

[0049] In the second aspect, the above method is applied to measure and / or process oil-based drill cuttings, and is used for real-time monitoring of the oil content in the oil-based drilling fluid recycling process.

[0050] By adopting the technical solution, the problems of delayed monitoring and inaccurate results in the oil-based drilling fluid recycling process in the prior art can be solved, and the processing efficiency and recycling effect are significantly improved.

[0051] Optionally, the above method is also used for environmental protection standard evaluation of oil-based drill cuttings in the drilling operation process.

[0052] By adopting the technical solution, the change of the oil content of the oil-based drill cuttings can be accurately monitored, and the exceeding standard condition can be found in time, thereby providing a reliable basis for environmental protection compliance management.

[0053] Optionally, the above method is also used for evaluation of the treatment effect of different treatment processes on oil-based drill cuttings.

[0054] By adopting the technical solution, the effect of different treatment processes can be accurately evaluated and compared.

[0055] In summary, the present application has at least one of the following beneficial technical effects:

[0056] The application firstly queries a dynamic extraction curve database according to sample lithology and a processing method, determines an optimal extraction time point by calculating a concentration change rate; multi-point sampling is performed during the extraction process, and the ambient temperature and pressure are measured simultaneously, an environmental influence model including a temperature influence sub-model and a pressure influence sub-model is established, and an environmental correction factor is obtained; infrared spectrum measurement is performed on the extraction liquid sample and data correction is performed, the average value and the standard deviation are calculated, and abnormal values are removed; finally, a segmented linear equation for different concentration ranges is used to calculate the final oil content; by considering the lithology characteristics, environmental influence and segmented linear relationship, the measurement accuracy and reliability are significantly improved;

[0057] The application firstly performs lithology determination on the collected oil-based drilling cuttings sample, obtains basic lithology information including rock type, structural characteristics and the like, then queries a pre-established lithology classification table according to the lithology information, obtains the corresponding processing method such as crushing granularity, extraction agent selection and the like, then queries a dynamic extraction curve database to obtain the standard dynamic extraction curve of the sample of this type, and finally determines the starting point of a certain time interval as the optimal extraction time point when the average concentration change rate in the continuous time interval is less than a set threshold value, thereby realizing accurate control of the extraction time and avoiding the problems caused by uniform setting of the extraction time in the traditional method.

[0058] The application firstly obtains actual temperature and pressure measurement values of the field environment, compares them with the standard test conditions, and calculates the temperature deviation and the pressure deviation; then inputs these deviation values into a pre-established environmental influence model, which is divided into a temperature influence sub-model and a pressure influence sub-model, wherein the temperature influence sub-model not only considers the temperature deviation, but also takes the sample water content as an important parameter, and the pressure influence sub-model combines the pressure deviation and the sample density for calculation; finally, the temperature correction coefficient and the pressure correction coefficient are multiplied to obtain the comprehensive environmental correction factor; the coupling effect of the temperature, pressure and other environmental factors and the sample physical characteristics is considered, so that the measurement result is more accurate and reliable. BRIEF DESCRIPTION OF DRAWINGS

[0059] Figure 1 Fig. 1 is a flowchart of an oil content measurement method for oil-based drilling cuttings according to an embodiment of the application;

[0060] Figure 2 Fig. 2 is a flowchart of step S100 in the oil content measurement method for oil-based drilling cuttings according to an embodiment of the application;

[0061] Figure 3 Fig. 3 is a flowchart of step S300 in the oil content measurement method for oil-based drilling cuttings according to an embodiment of the application;

[0062] Figure 4 Fig. 4 is a flowchart of step S330 in the oil content measurement method for oil-based drilling cuttings according to an embodiment of the application;

[0063] Figure 5 is a flowchart of step S400 in the oil content measurement method of oil-based drilling cuttings according to an embodiment of the present application;

[0064] Figure 6 is a flowchart of step S600 in the oil content measurement method of oil-based drilling cuttings according to an embodiment of the present application;

[0065] Figure 7 is a flowchart of step S620 in the oil content measurement method of oil-based drilling cuttings according to an embodiment of the present application. DETAILED DESCRIPTION

[0066] The terms used in the following embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to be limiting of the present application. As used in the specification and the appended claims of the application, the singular forms "a," "an" and "the" are intended to include both singular and plural forms, unless the context clearly indicates otherwise. It will be further understood that the terms "and / or," as used in the specification and in the claims, are used to mean any one of the items listed or all possible combinations of the items.

[0067] Hereinafter, the terms "first" and "second" are used only for the purpose of description and should not be understood as implying or suggesting relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more of the features, and in the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0068] The embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0069] In a first aspect, the present application provides an oil content measurement method of oil-based drilling cuttings, referring to Figure 1 , comprising the following steps:

[0070] S100, obtaining the lithology type and treatment method of the sample, and determining the optimal extraction time point according to the dynamic extraction curve corresponding to the lithology type and treatment method.

[0071] In this embodiment, the lithology type includes shale, sandstone, mudstone and limestone; the treatment method includes centrifugal method, extraction method and cleaning method. The dynamic extraction curve refers to the relationship curve of the oil concentration in the extraction liquid changing with the extraction time under fixed extraction conditions, and the optimal extraction time point is the time when the curve reaches the stable platform.

[0072] Specifically, the present application establishes a lithology type-treatment method-extraction curve mapping table. By querying the mapping table, corresponding dynamic extraction curve parameters are obtained, including time nodes of the rising period, the stable period and the decay period. The time node at the beginning of the stable period is selected as the optimal extraction time node. For shale, the optimal extraction time is 10-15 minutes; for sandstone, the optimal extraction time is 8-12 minutes.

[0073] S200, within the optimal extraction time, multi-point sampling is performed at a preset time interval to obtain extraction liquid samples at multiple time points.

[0074] In this embodiment, the preset time interval refers to the time interval for sampling within the optimal extraction time range, and the multi-point sampling is to improve the reliability of the measurement.

[0075] S300, measure the ambient temperature and pressure, and input the ambient temperature and pressure into a preset environmental influence model to obtain an environmental correction factor.

[0076] In this embodiment, the environmental influence model is a mathematical model describing the influence of temperature and pressure on the infrared spectrum measurement results, and the environmental correction factor is used to correct the measurement results.

[0077] Specifically, a thermometer and a pressure gauge are used to measure the temperature and pressure of the experimental environment, respectively. A temperature-pressure-correction factor table is established, and the environmental correction factor is obtained by table lookup.

[0078] S400, infrared spectrum measurement is performed on the plurality of extraction liquid samples to obtain an absorbance data sequence, and the absorbance data is corrected according to the environmental correction factor.

[0079] In this embodiment, the infrared spectrum measurement adopts the transmission method to measure the absorbance of the extraction liquid at the characteristic wavelength. The absorbance data sequence refers to the measurement result set of the samples at multiple time points.

[0080] Specifically, 2920-2940 cm - The wavenumber range is measured, and carbon tetrachloride is used as a reference. The extraction liquid is placed in a measurement cell with an optical path of 0.5-1 mm, and the scanning number is 16-32 times. The measured absorbance is corrected according to the environmental correction factor.

[0081] S500, according to the corrected absorbance data sequence, the average value and the standard deviation are calculated, and the effective measurement result is obtained after removing the abnormal value.

[0082] In this embodiment, the abnormal value refers to the measurement data deviating from the average value by more than a preset threshold. The effective measurement result is the average value of the data after removing the abnormal value.

[0083] Specifically, the arithmetic mean and the standard deviation of the absorbance data sequence are calculated, and the data points deviating from the mean value by more than 2 times the standard deviation are marked as outliers and removed. The mean value is recalculated as the effective measurement result.

[0084] S600, the effective measurement result is substituted into the pre-established segmented working curve to obtain the final oil content.

[0085] The segmented working curve includes a plurality of linear equations in different concentration ranges.

[0086] In this embodiment, the segmented working curve refers to a linear relationship equation between absorbance and oil content established in different concentration ranges.

[0087] Specifically, the oil content range is divided into a low concentration interval, a medium concentration interval and a high concentration interval. Linear equations for each interval are established by standard samples, and the corresponding working curve is selected according to the interval of the effective measurement result for calculation.

[0088] In one embodiment, with reference to Figure 2 In step S100, the lithology type and the treatment method of the sample are obtained, and the optimal extraction time point is determined according to the dynamic extraction curve corresponding to the lithology type and the treatment method, specifically including the following steps:

[0089] S110, the lithology type of the sample is obtained, and the corresponding treatment method is obtained by querying the preset lithology classification table according to the lithology type.

[0090] In this embodiment, the lithology classification table is a classification system established based on rock physical properties, which contains the correspondence between lithology types and recommended treatment methods. The classification table classifies rocks according to granularity, porosity, permeability and mineral composition, and each lithology type corresponds to one or more applicable treatment methods.

[0091] Specifically, the lithology classification table divides rocks into three categories according to granularity: coarse, medium and fine; according to porosity: high, medium and low; according to permeability: high, medium and low. These physical parameters form a multi-dimensional classification matrix, and each combination corresponds to a specific treatment method. Among them, high-porosity and high-permeability sandstone corresponds to centrifugal method treatment; low-porosity and low-permeability shale corresponds to extraction method treatment. The classification table also contains the process parameter range of the treatment method, which facilitates the operator to quickly determine the treatment conditions.

[0092] S120, based on the treatment method, the corresponding dynamic extraction curve is obtained by querying the pre-established dynamic extraction curve database.

[0093] In this embodiment, the dynamic extraction curve database stores extraction process data under different processing methods, including extraction time, extract concentration and extraction efficiency. The database is established through statistical analysis of a large amount of experimental data.

[0094] Specifically, the database is indexed according to processing methods, and each processing method contains multiple sets of extraction curve data. The data collection covers the initial stage, rapid rising stage, stable stage and decay stage of the entire extraction process. The extract concentration and extraction efficiency are expressed in relative percentage.

[0095] S130, calculate the average concentration change rate before and after each time point according to the dynamic extraction curve, and when the average concentration change rate is less than a preset threshold value in a continuous time interval of a preset length, determine the starting time point of the continuous time interval as the optimal extraction time point.

[0096] In this embodiment, the average concentration change rate refers to the ratio of the change amount of the extract concentration between adjacent time points to the time interval. The continuous time interval of a preset length refers to a time window for judging whether the extraction process has reached stability. The preset threshold value is the critical value of the concentration change rate for judging the stability of the extraction process.

[0097] Specifically, a continuous time interval of a certain length is selected, and the concentration change rate per unit time in the interval is calculated. When the concentration change rates of multiple consecutive data points are lower than the preset critical value, it is considered that the extraction process has reached stability, and the starting time point of the continuous interval is determined as the optimal extraction time point. The sliding time window method is used for calculation to ensure that the earliest stable time point is obtained, which can effectively avoid false stability judgment caused by random fluctuations.

[0098] In one embodiment, referring to Figure 3 In step S300, the ambient temperature and pressure are measured, and the ambient temperature and pressure are input into a preset environmental influence model to obtain an environmental correction factor, specifically including the following steps:

[0099] S310, obtain the temperature and pressure measurement values of the current environment.

[0100] In this embodiment, the temperature measurement value refers to the actual temperature reading obtained by using a thermometer in the measurement environment, and the pressure measurement value refers to the actual pressure reading obtained by using a pressure gauge in the measurement environment. The standard temperature and standard pressure refer to the reference environmental parameters specified by the laboratory.

[0101] Specifically, the ambient temperature is measured by using a mercury thermometer, and the measurement position is selected at four positions around the sample placement point, and the average value is taken as the temperature measurement value; the ambient pressure is measured by using a digital pressure gauge, and the data is recorded once every fixed time during the experiment. The standard temperature and standard pressure specified by the laboratory are recorded as fixed reference values in the working manual.

[0102] S320, compare the temperature and pressure measurement values with standard temperature and standard pressure respectively to obtain temperature deviation and pressure deviation.

[0103] In this embodiment, the temperature deviation represents the difference between the actual measured temperature and the standard temperature, and the pressure deviation represents the difference between the actual measured pressure and the standard pressure.

[0104] Specifically, a temperature-pressure deviation record table is established to compare the measurement values with the standard values. The record table includes five data items: measurement time, temperature measurement value, pressure measurement value, temperature deviation value, and pressure deviation value. When the temperature or pressure deviation exceeds the preset range, the system sends a reminder signal to prompt the operator to pay attention to the change in environmental conditions.

[0105] S330, calculate temperature correction coefficient and pressure correction coefficient through a preset environmental influence model according to the temperature deviation and the pressure deviation.

[0106] The environmental influence model includes a temperature influence sub-model and a pressure influence sub-model. The input parameters of the temperature influence sub-model include temperature deviation and sample moisture content, and the input parameters of the pressure influence sub-model include pressure deviation and sample density.

[0107] In this embodiment, the temperature influence sub-model describes the influence law of temperature change on the measurement result, and the pressure influence sub-model describes the influence law of pressure change on the measurement result. The sample moisture content and density are important parameters that affect the effect of environmental factors.

[0108] Specifically, the temperature influence sub-model adopts a segmented linear correction method to establish a corresponding relationship table of temperature deviation and correction coefficient. The relationship table is divided into multiple intervals according to the sample moisture content, and different correction coefficients are used in each interval. The pressure influence sub-model obtains the correction coefficient by querying the pressure-density correction curve graph, and the horizontal axis of the curve graph is the pressure deviation and the vertical axis is the correction coefficient. Different density intervals correspond to different curves. The temperature influence sub-model is expressed by a segmented linear function, for example, when the moisture content W≤5%, Kt=0.002×ΔT+1.0; when 5%<W≤15%, Kt=0.004×ΔT+1.0; when W>15%, Kt=0.006×ΔT+1.0, where Kt is the temperature correction coefficient, and ΔT is the temperature deviation. When the sample moisture content exceeds the preset threshold of 15%, the weighted correction formula is used, Kt correction=Kt×[1+0.05×(W-15%)] to adapt to the sensitive characteristics of high moisture content samples to temperature changes. The pressure influence sub-model adopts a density regional linear correction method, for example, when the density ρ≤1.2g / cm³, Kp=0.001×ΔP+1.0; when 1.2g / cm³<ρ≤2.0g / cm³, Kp=0.002×ΔP+1.0; when ρ>2.0g / cm³, Kp=0.003×ΔP+1.0, where Kp is the pressure correction coefficient, and ΔP is the pressure deviation. When the sample density exceeds the preset threshold of 2.0g / cm³, the weighted correction formula is used, Kp correction=Kp×[1+0.08×(ρ-2.0)].

[0109] Further, the environmental influence model of the present embodiment also introduces time response characteristics, considering the dynamic process of environmental parameter changes. Specifically, through continuous monitoring, it is found that the changes of environmental temperature and pressure do not instantaneously affect the measurement results, but there is a certain response lag. The present application establishes an environmental parameter change rate-response time table, and selects the corresponding delay correction coefficient according to the temperature and pressure change rate. For the case where the temperature change rate is greater than a first preset threshold or the pressure change rate is greater than a second preset threshold, a time period correction method is used, that is, the environmental parameters of the initial, intermediate and final states are recorded during the measurement process, and the actual correction coefficient at each time point is calculated by interpolation. This dynamic correction method considering the time response characteristics avoids the lag error that may be caused by the traditional single-point correction.

[0110] Further, the present embodiment establishes a historical correction coefficient database to record the temperature correction coefficient, the pressure correction coefficient and the corresponding measurement accuracy under different working conditions. When the cumulative number of measurements of a certain working condition reaches a preset threshold, the system automatically analyzes the distribution characteristics of the correction coefficient under the working condition to establish a working condition characteristic-correction coefficient mapping model.

[0111] Specifically, the calculation formula of the mapping model is Ki =∑Wj·Fj(Pi), wherein Ki is the correction coefficient prediction value under a certain working condition, Wj is the weight coefficient of different characteristic parameters, Fj(Pi) is the influence function corresponding to each characteristic parameter, and Pi is the working condition characteristic parameter. When the similarity between the new measurement working condition and a working condition characteristic in the historical database exceeds a preset threshold, the system will enable the mapping model under the working condition to predict the correction coefficient, and compare it with the real-time calculation value. If the deviation between the two exceeds the allowed range, the abnormal analysis process is triggered, including sample characteristic parameter re-measurement, environmental impact abnormality judgment, etc. Among them, the influence function Fj(Pi) adopts a linear similarity function form: F1(P1)=1-|P1-P1ref| / R1, F2(P2)=1-|P2-P2ref| / R2, F3(P3)=1-|P3-P3ref| / R3, F4(P4)=1-|P4-P4ref| / R4, wherein P1, P2, P3, and P4 are the temperature deviation, pressure deviation, water content, and density value of the current working condition, P1ref, P2ref, P3ref, and P4ref are the corresponding reference values of the historical working condition, and R1, R2, R3, and R4 are the maximum tolerance ranges of the parameters. When the influence function value is less than 0, take 0. The weight coefficients are set according to the importance of the parameters: temperature weight W1=0.4, pressure weight W2=0.3, water content weight W3=0.2, and density weight W4=0.1.

[0112] S340, multiply the temperature correction coefficient and the pressure correction coefficient to obtain an environmental correction factor.

[0113] In this embodiment, the environmental correction factor is the result of the comprehensive action of the temperature correction coefficient and the pressure correction coefficient, and is used for overall correction of the measurement data.

[0114] Specifically, a correction factor calculation table is established, and the temperature correction coefficient and the pressure correction coefficient are substituted into the calculation formula. When the product of the two correction coefficients is within a reasonable range, the value is directly used as the environmental correction factor; when the product exceeds the reasonable range, a secondary correction mechanism is started, and the correction is performed through a segmented function to ensure that the final correction factor has physical meaning.

[0115] In one embodiment, with reference to Figure 4 In step S330, the temperature correction coefficient and the pressure correction coefficient are calculated through a preset environmental impact model according to the temperature deviation and the pressure deviation, specifically including the following steps:

[0116] S331, measure the water content and density of the sample.

[0117] In this embodiment, the water content of the sample refers to the percentage of the water content in the sample to the total weight, and the density refers to the mass per unit volume of the sample.

[0118] S332, input the temperature deviation and sample moisture content into the temperature influence sub-model to obtain the temperature correction coefficient under different moisture contents.

[0119] In this embodiment, the temperature influence sub-model describes the influence law of temperature change on the measurement results under different moisture contents, is established based on a large amount of experimental data, and adopts a piecewise linear fitting mode to describe the relationship between the temperature correction coefficient and the temperature deviation.

[0120] Specifically, a moisture content grading correction table is established, and the moisture content is divided into a low value interval, a medium value interval and a high value interval. Each interval corresponds to a different temperature influence curve, and the slope of the curve increases with the increase of the moisture content. The calculation of the temperature correction coefficient adopts a table lookup interpolation method, that is, the interval to which the moisture content belongs is determined, and then the correction coefficient is calculated according to the temperature deviation.

[0121] S333, input the pressure deviation and sample density into the pressure influence sub-model to obtain the pressure correction coefficient under different densities.

[0122] When the sample moisture content is greater than a preset threshold, the temperature correction coefficient is weightedly corrected; and when the sample density is greater than a preset threshold, the pressure correction coefficient is weightedly corrected.

[0123] In this embodiment, the pressure influence sub-model describes the influence law of pressure change on the measurement results under different densities, adopts a density regional correction method, and establishes the corresponding relationship between the pressure correction coefficient and the pressure deviation.

[0124] Specifically, a density-pressure correction matrix is established, the horizontal axis is the pressure deviation interval, the vertical axis is the density interval, and the matrix element is the corresponding pressure correction coefficient. The initial correction coefficient is obtained by querying the matrix, and then the final pressure correction coefficient is obtained by linear interpolation calculation according to the actual density value.

[0125] When the sample moisture content exceeds the preset threshold, it indicates that the sample is more sensitive to the environmental temperature and needs to be specially treated. A weighting coefficient table is established, and the corresponding weighting coefficient is selected according to the degree of exceeding the threshold of the moisture content to correct the temperature correction coefficient. Similarly, when the sample density exceeds the preset threshold, it indicates that the pressure change has a greater influence on the sample, and the pressure correction coefficient needs to be adjusted by the weighting coefficient.

[0126] In one embodiment, with reference to Figure 5 , in step S400, the absorbance data is corrected according to the environmental correction factor, specifically including the following steps:

[0127] S410, obtaining a plurality of characteristic peak absorbance data of the extraction liquid sample in the absorption region of the hydrocarbon characteristic functional group.

[0128] In this embodiment, the hydrocarbon characteristic functional group absorption region refers to the wave number range in the infrared spectrum that can reflect the structural characteristics of hydrocarbon compounds. The characteristic peak absorbance data refers to the absorbance values measured at these specific wave number positions.

[0129] Specifically, a hydrocarbon characteristic peak identification table is established, containing the characteristic wave numbers of the three main absorption regions of C-H stretching vibration band, C-H bending vibration band, and C=C stretching vibration band. Multiple characteristic wave number points are selected in each region for measurement to form a characteristic peak data set.

[0130] S420, calculate the absorbance deviation of each characteristic peak under the influence of the environment according to the environmental correction factor.

[0131] In this embodiment, the absorbance deviation represents the degree of deviation of the measured absorbance value from the true value caused by environmental factors. The deviation is related to the environmental correction factor, the characteristic peak wave number position, and the absorbance size.

[0132] Specifically, a characteristic peak-environment response relationship table is established to record the sensitivity of different characteristic peaks to environmental changes. The response coefficient of each characteristic peak is obtained by looking up the table, and the response coefficient is multiplied by the environmental correction factor to obtain the absorbance deviation of each characteristic peak. Different response coefficients are used for characteristic peaks in different wave number ranges to reflect the wavelength dependence of environmental impact.

[0133] S430, correct and calculate the absorbance deviation and the absorbance data of the corresponding characteristic peak to obtain the corrected characteristic peak absorbance value.

[0134] In this embodiment, the correction calculation refers to the process of modifying the original absorbance data according to the calculated deviation. Different correction methods may be required for different characteristic peaks.

[0135] Specifically, a characteristic peak correction scheme library is established, including linear correction, exponential correction, and segmented correction. The appropriate correction scheme is selected according to the wave number position and absorbance size of the characteristic peak. For the main peak with large absorbance, segmented correction is used, and for the secondary peak with small absorbance, linear correction is used to ensure the rationality of the correction result.

[0136] S440, normalize the corrected characteristic peak absorbance value according to the concentration of the extraction liquid to obtain the final correction result.

[0137] In one embodiment, referring to Figure 6 In step S600, the effective measurement result is substituted into the pre-established segmented working curve to obtain the final oil content, specifically including the following steps:

[0138] S610, select the corresponding concentration range interval according to the numerical range of the effective measurement result.

[0139] In this embodiment, the numerical range refers to the interval between the maximum and minimum values of the effective measurement results. The concentration range interval refers to the interval of measurement results corresponding to different oil content levels divided in advance.

[0140] Specifically, a measurement result partition table is established to divide the entire measurement range into a low concentration interval, a medium concentration interval, and a high concentration interval. Upper and lower threshold values are set for each interval, and the belonging interval is determined by comparing the effective measurement result with the threshold value. The partition table is divided based on a large amount of test data of standard samples, which ensures a good linear relationship between the measurement result and the oil content in each interval.

[0141] S620, within the concentration range interval, the corresponding linear equation parameters are obtained.

[0142] In this embodiment, the linear equation parameters include the slope and the intercept, which are used to describe the quantitative relationship between the measurement result and the oil content. Each concentration interval corresponds to a unique set of parameter values.

[0143] Specifically, a partition parameter matrix is established to record the linear equation parameters of each concentration interval. The parameter matrix is obtained by standard sample calibration, and the least squares method is used to fit the slope and intercept of each interval. To improve the reliability of the parameters, standard samples are used for verification and updating regularly to ensure the calculation accuracy.

[0144] S630, the effective measurement result is substituted into the selected linear equation to calculate the preliminary oil content.

[0145] In this embodiment, the preliminary oil content refers to the result calculated only considering the linear relationship, which is an intermediate value without volume correction, reflecting the basic correspondence between the measurement result and the oil content.

[0146] Specifically, according to the selected concentration interval, the corresponding slope and intercept are extracted from the parameter matrix. The effective measurement result is substituted into the linear equation, and the preliminary oil content is obtained through simple multiplication and addition operations. For measurement results close to the interval boundary, a weighted average method is used for calculation to avoid sudden changes at the transition of the interval.

[0147] S640, according to the mass of the sample and the volume of the extractant, the preliminary oil content is volume corrected to obtain the final oil content.

[0148] In this embodiment, volume correction refers to the correction of the calculation result considering the proportional relationship between the sample mass and the extractant volume.

[0149] Specifically, a volume correction coefficient table is established to record the correction coefficients corresponding to different mass-volume ratios. The correction coefficient is obtained by looking up the table, and the final oil content is obtained by multiplying the preliminary oil content by the correction coefficient. The correction coefficient table is established based on the principle of mass conservation, and the relationship between the extraction efficiency and the mass-volume ratio is considered.

[0150] In one embodiment, with reference to Figure 7 In step S620, the linear equation parameters corresponding to the concentration range interval are obtained, specifically including the following steps:

[0151] S621, obtaining the absorbance and oil content data pairs of the standard sample according to the concentration range interval.

[0152] In this embodiment, the standard sample refers to a calibration sample with known accurate oil content, and the data pair refers to a data combination composed of the absorbance measurement value of the standard sample and its corresponding actual oil content value.

[0153] Specifically, a standard sample database is established, which contains standard sample information in the low concentration interval, the medium concentration interval, and the high concentration interval. A plurality of standard samples with concentration gradients are selected in each interval, and their absorbance measurement values and actual oil contents are recorded. The selection of standard samples follows the principle of uniform distribution to ensure that the data pairs can fully reflect the change law of the entire interval.

[0154] S622, linear fitting is performed on the absorbance and oil content to obtain the slope and intercept parameters.

[0155] In this embodiment, linear fitting refers to determining the best slope and intercept by the least squares method to minimize the overall deviation of the fitted straight line from the actual data points.

[0156] Specifically, a fitting parameter calculation table is established to record the data processing methods of different intervals. Weighted least squares method is used for fitting, and data points with smaller measurement uncertainty are given larger weights. The optimal solution of the slope and intercept is obtained by matrix operation, and its confidence interval is recorded.

[0157] S623, calculating the goodness of fit of the standard sample in the corresponding interval, and determining that the slope and intercept parameters are valid when the goodness of fit is greater than a preset threshold.

[0158] Wherein, for different concentration range intervals, the values of the slope and intercept parameters meet the preset interval limitation condition.

[0159] In this embodiment, the goodness of fit refers to the degree of explanation of the fitted straight line to the actual data, which reflects the reliability of the linear relationship. The preset threshold is used to judge whether the fitting result meets the accuracy requirement.

[0160] Specifically, a goodness-of-fit evaluation system is established, including three evaluation indexes of correlation coefficient, residual sum of squares and prediction error. The reliability of the fitting result is judged by a comprehensive scoring method. When the score exceeds the preset threshold, the fitting parameters are accepted; otherwise, the standard sample needs to be reselected or the fitting method needs to be adjusted.

[0161] It should be understood that the size of the serial number of each step in the above embodiment does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the application.

[0162] In a second aspect, the application provides the above method for measuring and / or processing oil-based drill cuttings. In the oil-based drilling fluid recycling and processing site, the above-mentioned measurement method is used for real-time monitoring of oil content. Sampling points are arranged at the inlet and outlet of the processing device, and samples are collected every 30 minutes for measurement. The measurement results are displayed in real time through the on-site control system and are linked with the processing parameters. Specifically, when the oil content of the inlet sample exceeds the design value of the processing system, the system automatically adjusts the feeding rate; when the oil content of the outlet sample exceeds the environmental protection limit value, the system sends an alarm signal and automatically increases the processing time. Through real-time monitoring and linkage control, the processing process is always in the best state, improving the processing efficiency and recovery effect.

[0163] In the environmental management of drilling sites, the above-mentioned measurement method is used for compliance evaluation of oil-based drill cuttings. Multiple monitoring points are arranged in the temporary storage area and processing area of the drill cuttings, and samples are collected regularly according to the sampling specification. Specifically, a field monitoring record table is established, including four basic information items of sample number, sampling location, measurement time and oil content value. When the monitoring results show that the oil content of a certain point is close to the limit value, the sampling frequency of that point is increased. Through standardized monitoring and recording, complete data support is provided for environmental compliance evaluation.

[0164] In the process optimization process, the above-mentioned measurement method is used to evaluate the treatment effect of different processes. Three typical processes of thermal desorption, chemical extraction and microwave treatment are selected for comparative test. Specifically, an evaluation index system is established, including three core indexes of oil content after treatment, oil recovery rate and energy consumption level. The change of oil content before and after treatment is accurately obtained by using the measurement method of the application through continuous monitoring of the operation data of each process. According to the evaluation results, the most suitable processing process scheme for the site conditions is selected.

[0165] The above are preferred embodiments of the application, and do not limit the protection scope of the application, therefore: any equivalent changes made according to the structure, shape, principle of the application should be covered within the protection scope of the application.

Claims

1. A method for measuring the oil content of oil-based drill cuttings, characterized in that, Includes the following steps: Obtain the lithological type and processing method of the sample, and determine the optimal extraction time point based on the dynamic extraction curve corresponding to the lithological type and processing method; During the optimal extraction time, multiple samples are taken at preset time intervals to obtain extract samples at multiple time points. Measure the ambient temperature and pressure, input the ambient temperature and pressure into a preset environmental impact model, and obtain the environmental correction factor; Infrared spectroscopy measurements were performed on multiple extract samples to obtain absorbance data sequences, and the absorbance data were corrected according to the environmental correction factor. Based on the corrected absorbance data sequence, the mean and standard deviation are calculated, and the valid measurement results are obtained after removing outliers. Substituting the effective measurement results into the pre-established segmented working curve, the final oil content is obtained, wherein the segmented working curve includes multiple linear equations with different concentration ranges; The process includes measuring ambient temperature and pressure, inputting the ambient temperature and pressure into a preset environmental impact model to obtain an environmental correction factor, specifically including the following steps: Acquire current ambient temperature and pressure measurements; The measured temperature and pressure values ​​are compared with standard temperature and standard pressure, respectively, to obtain the temperature deviation and pressure deviation; Based on the temperature deviation and pressure deviation, temperature correction coefficients and pressure correction coefficients are calculated using a preset environmental impact model. The environmental impact model includes a temperature impact sub-model and a pressure impact sub-model. The input parameters of the temperature impact sub-model include temperature deviation and sample moisture content, and the input parameters of the pressure impact sub-model include pressure deviation and sample density. Multiply the temperature correction factor and the pressure correction factor together to obtain the environmental correction factor; Based on the temperature and pressure deviations, temperature and pressure correction coefficients are calculated using a preset environmental impact model, specifically including the following steps: Measure the moisture content and density of the sample; The temperature deviation and sample moisture content are input into the temperature influence sub-model to obtain temperature correction coefficients for different moisture contents. The pressure deviation and sample density are input into the pressure influence sub-model to obtain the pressure correction coefficients under different densities; Specifically, when the sample moisture content is greater than a preset threshold, the temperature correction coefficient is weighted and corrected; when the sample density is greater than a preset threshold, the pressure correction coefficient is weighted and corrected.

2. The method for measuring the oil content of oil-based drill cuttings according to claim 1, characterized in that, The lithological type and processing method of the sample are obtained, and the optimal extraction time point is determined based on the dynamic extraction curve corresponding to the lithological type and processing method. This process specifically includes the following steps: Obtain the lithology type of the sample, and query the preset lithology classification table according to the lithology type to obtain the corresponding processing method; Based on the processing method, a pre-established dynamic extraction curve database is queried to obtain the corresponding dynamic extraction curve; The average concentration change rate before and after each time point is calculated based on the dynamic extraction curve. When the average concentration change rate is less than a preset threshold within a continuous time interval of a preset length, the starting time point of the continuous time interval is determined as the optimal extraction time point.

3. The method for measuring the oil content of oil-based drill cuttings according to claim 1, characterized in that, The absorbance data is corrected according to the environmental correction factor, specifically including the following steps: Obtain absorbance data of multiple characteristic peaks in the absorption region of hydrocarbon functional groups in the extract sample; Calculate the absorbance deviation of each characteristic peak under environmental influence based on the environmental correction factor. The absorbance deviation is corrected by calculating the absorbance data of the corresponding characteristic peak to obtain the corrected absorbance value of the characteristic peak. The corrected characteristic peak absorbance values ​​were normalized based on the concentration of the extract to obtain the final corrected result.

4. The method for measuring the oil content of oil-based drill cuttings according to claim 1, characterized in that, Substituting the valid measurement results into the pre-established segmented working curve, the final oil content is obtained, specifically including the following steps: Based on the numerical range of the effective measurement results, select the corresponding concentration range interval; Within the concentration range, obtain the corresponding linear equation parameters; Substitute the effective measurement results into the selected linear equation to calculate the preliminary oil content; Based on the sample mass and extractant volume, the preliminary oil content is corrected by volume to obtain the final oil content.

5. The method for measuring the oil content of oil-based drill cuttings according to claim 4, characterized in that, Within the concentration range, the corresponding linear equation parameters are obtained, specifically including the following steps: The absorbance and oil content data of the standard sample were obtained according to the concentration range. Linear fitting was performed on the absorbance and oil content to obtain the slope and intercept parameters; Calculate the goodness of fit of the standard sample in the corresponding interval. When the goodness of fit is greater than a preset threshold, determine that the slope and intercept parameters are valid. Specifically, for different concentration ranges, the values ​​of the slope and intercept parameters satisfy preset range limiting conditions.

6. The application of the method according to any one of claims 1-5 in measuring and / or treating oil-based drill cuttings, characterized in that, Used for real-time monitoring of oil content during the recovery and treatment of oil-based drilling fluids.

7. The application of the method according to any one of claims 1-5 in measuring and / or treating oil-based drill cuttings, characterized in that, Used for environmental compliance assessment of oil-based drill cuttings during drilling operations.

8. The application of the method according to any one of claims 1-5 in measuring and / or treating oil-based drill cuttings, characterized in that, Used to evaluate the effectiveness of different processing techniques on oil-based drill cuttings.

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