A method of oil and gas well production analysis

Abstract

The application discloses an oil and gas well plug analysis method, comprising the following steps: obtaining the weight difference before and after drying as the water content of the sample; respectively performing burning treatment on the dried sample in a low-temperature section and a high-temperature section, the weight loss of the sample in the low-temperature section including the total amount of organic matter, sulfur and other volatile substances, and the weight loss of the sample in the high-temperature section including the weight of carbon dioxide lost when carbonates are converted into oxides; extracting and separating the organic matter and inorganic matter from the dried sample through different polarity organic solvents; obtaining the content of the organic matter and the inorganic matter; comparing the characterization results with a fingerprint library I and a fingerprint library II, matching the output sample with high similarity; and finally determining the output component, content and source. The analysis method has high accuracy, can greatly save the analysis time, and has obvious guiding significance for preventing the formation of the plug and removing the plug.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of oil and gas field exploration and development, and relates to a method for analyzing plugging materials in carbonate rock, sandstone, shale reservoirs and wellbore and ground systems of conventional oil and gas, shale oil and gas, tight oil and gas, igneous rock, etc., in particular to a method for analyzing organic and inorganic plugging materials in well bottom, wellbore, ground, etc., and specifically to a method for analyzing complex output materials of oil and gas wells. BACKGROUND

[0002] Plugging removal is an effective technology for ensuring the production increase of oil and gas wells and the injection increase of injection wells. Actual oil and gas reservoirs may be plugged due to changes in production parameters and systems and introduction of foreign substances, which affects the production of oil and gas wells and the injection of injection wells. In the wellbore and ground gathering and transportation system of oil and gas production wells, complex plugging such as wellbore dirt and hydrate may be caused due to introduction of foreign substances or changes in production system, which brings huge safety risk to high-pressure gas wells or pressurized gathering and transportation pipelines. At present, hydrate prevention and removal are mainly considered, and the source and analysis of plugging materials are less considered. The similar literatures are as follows:

[0003] An oil well wellbore plugging removal method detects the opening size of the inside of the wellbore, judges the plugging level in the wellbore according to the opening size, and includes light plugging and heavy plugging. When the plugging level in the wellbore is judged as the heavy plugging, a dissolving agent is used to pressurize and positively extrude the inner wall of the wellbore. The oil well wellbore plugging removal method solves the technical problem of poor plugging removal effect of the existing plugging removal method for serious plugging oil wells.

[0004] A ground injection system for oil well plugging removal includes a pressurized injection device, a plugging removal agent tank and a coiled tubing. The inlet of the pressurized injection device is in communication with the outlet of the plugging removal agent tank, the outlet of the pressurized injection device is in communication with an oil production pipe, one end of the coiled tubing is inserted into the annular sleeve hollow formed between the oil production pipe and a casing, and the other end of the coiled tubing is in communication with the inlet of a suction device, and the outlet of the suction device is in communication with the inlet of the plugging removal agent tank. The ground injection system for oil well plugging removal can realize the circulation flow of the plugging removal agent in the oil production pipe, can improve the plugging removal efficiency and reduce the plugging removal cost, and can also avoid the pollution of impurities in the plugging removal agent to the formation.

[0005] The application discloses a gas well borehole plugging removal method, and discloses a gas field borehole plugging removal method.The gas field plugging removal agent is composed of an acidic plugging removal agent and an alkaline chelating agent, and is suitable for gas wells and oil wells.The acidic plugging removal agent mainly dissolves CaCO3, FeCO3, FeS and other products in the well borehole by means of acid salt reaction, and the alkaline chelating agent mainly dissolves BaSO4, CaSO4 and other acid-insoluble substances in the well borehole by means of chelation mechanism.After the plugging removal agent is used to remove the plugging in the well borehole, the gas production and oil production increase rapidly, the casing pressure difference decreases obviously, and the plugging removal effect is remarkable.

[0006] The application discloses a method for removing hydrate plugging in a gas production well borehole, which comprises the following steps: pumping an acidic working liquid into the well borehole in which hydrate plugging occurs, and then injecting a heating unit wrapped with calcium oxide into the well borehole.

[0007] The existing inventions and researches are mostly concentrated in the selection of plugging removal liquid and the analysis of plugging matters, and the analysis method of plugging matters is less researched, and the existing plugging matter analysis has the following defects:

[0008] (1) The existing analysis method is time-consuming, and cannot meet the technical requirement of urgently solving the plugging on site, and according to the current plugging matter analysis process, it takes at least more than 25 working days to find out the approximate composition of the plugging matter.

[0009] (2) The existing analysis method has low accuracy, the inferred plugging matter has low accuracy, the plugging removal liquid cannot be accurately selected, the conventional acid liquid is repeatedly tested at present, the plugging removal liquid system is recommended after the repeated test of the commonly used solvent, the type and source of the plugging matter cannot be determined, the targeted plugging removal cannot be achieved, and the on-site effect cannot be guaranteed. SUMMARY

[0010] The technical problem to be solved by the application is that the existing plugging matter analysis method has the problems of long time consumption and low inference accuracy, and the application provides an oil and gas well production matter analysis method, which has short analysis time consumption and high analysis result accuracy, is beneficial to effectively removing the plugging of a reservoir, a well borehole and a ground gathering and transportation system, and is beneficial to effectively taking the plugging matter out of a plugging position.

[0011] The application is achieved by the following technical scheme.

[0012] An oil and gas well production matter analysis method comprises the following steps.

[0013] Step 1, drying treatment of a sample: the weight difference before and after drying is taken as the water content of the sample.

[0014] Step 2, burning separation treatment: the sample after drying in step 1 is subjected to burning treatment in the low-temperature section and the high-temperature section respectively, the weight loss of the sample in the low-temperature section includes the total amount of organic matter, sulfur and other volatile substances, and the weight loss of the sample in the high-temperature section includes the weight of carbon dioxide lost by the conversion of carbonates into oxides; the dried sample is subjected to elemental quantitative characterization;

[0015] Step 3, extraction and purification treatment: the sample after drying in step 1 is subjected to extraction and separation by different polarity organic solvents to obtain organic matter and inorganic matter; the organic matter and the inorganic matter are characterized qualitatively and quantitatively to obtain the content of the organic matter and the content of the inorganic matter; the extracted organic matter is analyzed to determine the content of the organic matter at different stages, the functional groups, the type and content of insoluble matter after burning;

[0016] Step 4, fingerprint library comparison treatment: the characterization results of step 3 are compared with the fingerprint library I and the fingerprint library II to match the output sample with high similarity;

[0017] Step 5, output product inference treatment: the type of the output product and the weight percentage of water, organic matter and inorganic matter in the output product are determined;

[0018] The values calculated by the Euclidean distance, the correlation coefficient and the cosine of the included angle are taken as the characteristic parameters for judging the similarity, and the similarity of the fingerprint library I is greater than 90%, and the similarity of the fingerprint library II is greater than 85%, which is judged as being consistent with the fingerprint library data;

[0019] The fingerprint library I refers to a chemical additive fingerprint library, and the fingerprint library II refers to an output product composition fingerprint library.

[0020] The oil and gas well output product analysis method provided by the application mainly performs qualitative and quantitative characterization analysis on the output product (referred to as a blocking material or an output product) blocking the oil and gas channel, calculates the source by using a fingerprint library technology, the analysis accuracy of the blocking material is obviously improved, the analysis time can be greatly saved, and the selection of a blocking removal fluid is more targeted. Through the above method, at least the following parameters are analyzed: water content, inorganic component, organic component, and the mass fraction data of each component is normalized to 100%; among the inorganic component, the acid-insoluble content and the substance, carbonates are included; among the organic component, saturated hydrocarbons, fatty acids, amides, long-chain carboxylic acids and sulfur-containing substances are included, and the possible introduction source is inferred; further, a blocking removal fluid with good blocking removal performance on site can be selected according to the inferred result.

[0021] Common characterization analysis methods for the blocking material and the separated substances include infrared, chromatography, mass spectrometry, HPCE electrophoresis, X-ray diffraction, energy spectrum scanning, NMR nuclear magnetic resonance and the like.

[0022] Further preferably, in the step 2, the temperature range of the low-temperature section is 550±10℃, and the temperature range of the high-temperature section is 950±10℃.

[0023] Further preferably, in the step 3, the dried output is first extracted with an organic solvent with a small polarity, then gradually extracted with an organic solvent with an increasing polarity, and finally all the organic substances are extracted and separated.

[0024] Further preferably, in the step 3, the output is weighed, soaked in an organic solvent with the smallest polarity for 2-6 hours, and then stirred and centrifuged; the upper liquid is taken out, and the extraction is continued with an organic solvent with an increasing polarity, and the process is repeated 3-6 times.

[0025] Further preferably, in the step 3, the organic solvent includes one or more of ethyl cyanide, petroleum ether, methanol, acetone, ethyl acetate, and diethyl ether.

[0026] Further preferably, in the step 3, the organic solvent includes a binary mixture of methanol and acetone, and / or a binary mixture of methanol and ethyl acetate, and / or a binary mixture of ethyl acetate and diethyl ether.

[0027] Further preferably, in the step 3, in the binary mixture of methanol and acetone, the mass ratio of methanol to acetone is 3:1-10:1; in the binary mixture of methanol and ethyl acetate, the mass ratio of ethyl acetate to methanol is 3:1-10:1; and in the binary mixture of ethyl acetate and diethyl ether, the mass ratio of ethyl acetate to diethyl ether is 3:1-10:1.

[0028] Further preferably, in the step 3, after the organic mixture obtained by extraction with different organic solvents is separated by gel filtration, ion exchange, and chromatography at a separation pressure of less than 5 MPa, each single-component organic substance is obtained, and the organic mixture and each single-component organic substance are subjected to qualitative and quantitative characterization analysis.

[0029] Further preferably, in the step 3, the inorganic substance obtained after the organic solvent extraction and separation is dissolved in an acid solution to obtain acid-soluble inorganic substances and acid-insoluble inorganic substances, and the acid-soluble inorganic substances and the acid-insoluble inorganic substances are subjected to qualitative and quantitative characterization analysis; the acid solution is a hydrochloric acid solution with a mass concentration of 15%-25%, or a nitric acid solution with a mass concentration of 50%-70%, or a mixed solution of hydrochloric acid and nitric acid with a volume ratio of 3:1.

[0030] For the insoluble after extraction, can first use infrared detection of its functional groups; then using the above acid solution dissolution; for acid insoluble dried constant weight, analysis of acid insoluble content, using infrared spectrometer, X-ray energy spectrum and / or X-ray diffractometer for qualitative analysis of the elements and mineral type of the output sample; for acid solution after the filtrate constant volume, using ICP quantitative analysis of the metal elements and content; combined with the results of the analysis and energy spectrum analysis structure comprehensive inference inorganic composition and content.

[0031] Further preferably, the fingerprint library I and the fingerprint library II are based on the following detection methods: spectroscopy, chromatography, mass spectrometry, energy spectrum method; the spectroscopy includes ultraviolet, infrared, nuclear magnetic resonance, X-ray diffraction; the chromatography includes thin layer chromatography, high performance liquid chromatography, high performance capillary electrophoresis.

[0032] By characterizing and analyzing all possible foreign chemical additives entering the wellbore or pipeline through drilling, well completion, reservoir reconstruction, foam drainage, pressure boosting mining, water injection, etc., a characterization spectrum is obtained, and a chemical additive fingerprint library I is established in a genetic algorithm coding manner; similarly, all possible plugs in oil and gas wells are characterized and analyzed, a characterization spectrum is obtained, and a product composition fingerprint library II is established in a genetic algorithm coding manner.

[0033] Further preferably, the chemical additives include drilling mud chemical additives, well completion chemical additives, reservoir reconstruction chemical additives, foam drainage chemical additives, pressure boosting mining chemical additives, oil production chemical agents, water injection well chemical additives.

[0034] The drilling mud chemical additives include oil phase, water phase, emulsifier, oil wetting agent, oleophilic colloid, lime, weighting material, etc.; the well completion chemical additives include fluid loss reducer, dispersant, resistance reducer, weighting agent, coagulant, retarder, etc.; the reservoir reconstruction chemical additives include thickening agent, corrosion inhibitor, iron stabilizer clay stabilizer, surfactant, etc.; the foam drainage chemical additives include surfactant, high molecular polymer stabilizer, defoaming agent, etc.; the pressure boosting mining chemical additives include compressor oil, etc.; the water injection well chemical additives include plug remover, chelating agent, etc.

[0035] Further preferably, in step 4, the similarity of the characteristic variable matching is calculated by three parameters of Euclidean distance, correlation coefficient and included angle cosine.

[0036] Further preferably, the Euclidean distance calculation formula is shown as formula (1):

[0037]

[0038] In formula (1), X ikXi represents the kth characteristic variable value of the ith additive and the pre-separation product sample, k = 1, 2,..., m; X rk Xi represents the kth characteristic variable value of the standard fingerprint library I or the fingerprint library II, k = 1, 2,..., m.

[0039] Further preferably, the calculation formula of the correlation coefficient is shown as formula (2):

[0040]

[0041] In formula (2), Xi represents the kth characteristic variable value of the ith additive and the pre-separation product sample, k = 1, 2,..., m; X ik Xi represents the kth characteristic variable value of the ith additive and the pre-separation product sample, k = 1, 2,..., m; X i Xi represents the mean value of all variables of the ith sample; X r Xi represents the mean value of all variables of the characteristic peaks of the standard fingerprint library I or the fingerprint library II, X rk Xi represents the kth characteristic variable value of the characteristic peaks of the standard fingerprint library I or the fingerprint library II, k = 1, 2,..., m.

[0042] Further preferably, the calculation formula of the cosine of the included angle is shown as formula (3)

[0043]

[0044] In formula (3), Xi represents the kth characteristic variable value of the ith additive and the pre-separation product sample, k = 1, 2,..., m; X ik Xi represents the kth characteristic variable value of the ith additive and the pre-separation product sample, k = 1, 2,..., m; X rk Xi represents the kth characteristic variable value of the characteristic peaks of the standard fingerprint library I or the fingerprint library II, k = 1, 2,..., m.

[0045] Further preferably, the characteristic variables include peak area, peak height, and retention time for characterizing the analysis spectrum; the values calculated by the Euclidean distance, the correlation coefficient, and the cosine of the included angle are weighted by 30%, 30%, and 40% respectively to obtain the values as the characteristic parameters for judging the similarity; for the fingerprint library I, the similarity is greater than 90%, and for the fingerprint library II, the similarity is greater than 85%, which is judged as that the detected product is consistent with the fingerprint library data. In addition, the mean vector is the average value of not less than 5 test results of the standard characteristic peaks under the same conditions.

[0046] As based on three characteristic variables key values of main peak height, characteristic peak area and retention time, the distance from peak tip to peak valley is more than 2 / 3 of the peak height, the fluctuation of peak retention time is in ±(5-10)%, the data of fingerprint spectrum library I and fingerprint spectrum library II are characterized by using three parameters of Euclidean distance, correlation coefficient and included angle cosine, the characteristic parameters are calculated according to weights of 30%, 30% and 40%, and the values obtained by optimizing 2 decimal parameters are the characteristic parameters.

[0047] The present application has the following advantages and beneficial effects:

[0048] The present application establishes a rapid analysis process by "drying-burning-extraction purification-fingerprint spectrum library comparison-output inference", mainly carries out qualitative and quantitative analysis on the output that blocks the oil and gas channel (referred to as blocking material), and calculates the source by using fingerprint spectrum library technology; the established fingerprint spectrum library uses three key values of main peak height, characteristic peak area and retention time as main parameters of the database, the similarity of the blocking material sample and the established additive spectrum library 1 is greater than 90%, and the similarity of the output fingerprint spectrum library 2 is greater than 85%, so that it is considered to be relatively similar.

[0049] The analysis time of the present application is shortened to about 7 working days, compared with the prior art, the analysis method has high accuracy, can greatly save analysis time, obviously improves the pertinence of liquid blocking selection and the liquid blocking effect, and has obvious guiding significance for preventing the formation and removal of the blocking material. BRIEF DESCRIPTION OF DRAWINGS

[0050] The drawings described herein are used to provide further understanding of the embodiments of the present application, constitute a part of the present application, and do not constitute a limitation on the embodiments of the present application. In the drawings:

[0051] Figure 1 It is the analysis flowchart of the present application: indicating the blocking material component analysis flowchart;

[0052] Figure 2 It is the analysis flowchart of the present application: indicating the fingerprint spectrum comparison analysis flowchart;

[0053] Figure 3 It is the fingerprint spectrum of the blocking material of the present application;

[0054] Figure 4 It is the fingerprint spectrum of the output 1;

[0055] Figure 5 It is the fingerprint spectrum of the output 2;

[0056] Figure 6 It is the fingerprint spectrum of the additive 1;

[0057] Figure 7Fingerprint of additive 2;

[0058] Figure 8 Fingerprint of additive 3;

[0059] Figure 9 Fingerprint of additive 4;

[0060] Figure 10 Fingerprint of additive 5;

[0061] Figure 11 Fingerprint of additive 6;

[0062] Figure 12 Energy spectrum analysis diagram of the present application;

[0063] Figure 13 Infrared spectrum of the plug of the present application;

[0064] Figure 14 Petroleum ether extract of the present application;

[0065] Figure 15 Infrared spectrum of the petroleum ether extract of the present application;

[0066] Figure 16 Ethyl acetate extract of the present application;

[0067] Figure 17 Infrared spectrum of the ethyl acetate extract of the present application;

[0068] Figure 18 Methanol:acetone extract of the present application;

[0069] Figure 19 Infrared spectrum of the methanol:acetone extract of the present application;

[0070] Figure 20 Infrared spectrum of the acid-insoluble substance of the present application;

[0071] Figure 21 Appearance of the plug of the present application as is;

[0072] Figure 22 Appearance of the plug of the present application after being unblocked;

[0073] Figure 23 Acidizing fracturing operation curve of the present application. DETAILED DESCRIPTION

[0074] In order to make the objects, technical solutions and advantages of the present application clearer, further detailed description will be given to the present application in combination with embodiments and drawings, and the schematic embodiments of the present application and the description thereof are only used for explaining the present application, and do not limit the present application.

[0075] Example 1

[0076] The present embodiment provides a method for analyzing the output of an oil and gas well, and the specific steps are shown as follows:

[0077] Step 1, select the plug sample, weigh it and place it in a container, and perform infrared drying to constant weight.

[0078] Step 2, take the first portion of the dried plug sample and perform 550°C and 950°C burning. The weight loss at 550°C mainly includes the total amount of organic matter, sulfur and other volatile substances in the plug. The weight loss at 950°C mainly includes the weight of carbonates in the plug being converted to oxides and losing carbon dioxide.

[0079] Step 3, take the second portion of the dried plug sample and perform extraction with different polar solvents:

[0080] 1) First extraction: soak the plug sample in petroleum ether organic solvent for 4 hours, stir at a speed of 1000 r / min, then perform centrifugal treatment, take the upper liquid, obtain the first extraction liquid, and further separate each organic component in the first extraction liquid into a single component using chromatography at a pressure of 2-3 MPa;

[0081] 2) Second extraction: increase the polarity of the solvent, soak the insoluble material of the first extraction in ethyl acetate organic solvent for 4 hours, stir at a speed of 1000 r / min, then perform centrifugal treatment, take the upper liquid, obtain the second extraction liquid, and further separate each organic component in the second extraction liquid into a single component using chromatography at a pressure of 2-3 MPa;

[0082] 3) Third extraction: further increase the polarity of the solvent, soak the insoluble material of the second extraction in a binary mixed organic solvent of methanol and acetone (mass ratio of methanol: acetone = 5:1) for 4 hours, stir at a speed of 1000 r / min, then perform centrifugal treatment, take the upper liquid, obtain the third extraction liquid, and further separate each organic component in the third extraction liquid into a single component using chromatography at a pressure of 2-3 MPa; the mass ratio of methanol and acetone is 5:1.

[0083] Dry and weigh the third extraction liquid and the remaining precipitate, which not only separates the organic matter and inorganic matter, but also obtains the content of the organic matter in the extraction liquid and the remaining inorganic matter. After extraction with different organic solvents, the organic mixture is separated using gel filtration, ion exchange, and chromatography at a separation pressure of <5 MPa to obtain each single-component organic matter. The analysis results are entered into a database, numerically processed, and the results are shown in Table 4,

[0084] Based on the above processing steps, the characterization analysis is as follows:

[0085] (1) Construct a plug fingerprint and compare it with fingerprint library I and fingerprint library II

[0086] The clogging material fingerprint spectrum and the fingerprint spectrum library I and the fingerprint spectrum library II in this embodiment are all infrared characterization spectra.

[0087] In the fingerprint spectrum library II, based on intuitive observation, the clogging material 1 fingerprint spectrum library II and the clogging material 2 fingerprint spectrum library II are preliminarily selected for comparison with the clogging material fingerprint spectrum.

[0088] In the fingerprint spectrum library II, based on intuitive observation, the clogging material 1 fingerprint spectrum library II and the clogging material 2 fingerprint spectrum library II are preliminarily selected for comparison with the clogging material fingerprint spectrum. Figures 3-11 As shown in the figure.

[0089] The comparison analysis results are shown in Tables 1 and 2.

[0090] Table 1 Comparison table of clogging material composition characteristic spectrum

[0091]

[0092] Table 2 Comparison table of additive fingerprint spectrum

[0093]

[0094]

[0095] (2) Preliminary analysis of clogging material content

[0096] The clogging material sample is dried by infrared rays at 60°C for 48h, the weight change of a certain amount of sample before and after drying is determined, and the weight of the clogging material sample before drying is divided by the weight of the clogging material sample before drying, that is, the moisture content in the clogging material sample, the moisture content in this embodiment is 25.2%.

[0097] The dried clogging material is analyzed by energy spectrum electron microscopy, mainly containing metal elements such as iron, aluminum, calcium, magnesium, sodium and potassium, and non-metal elements such as carbon, oxygen, sulfur, chlorine and silicon, and the results are shown in Table 3. Figure 12 and Table 3.

[0098] Table 3 Energy spectrum electron microscopy element analysis results

[0099] Element wt. % C 63.17 O 25.07 Na 0.11 Mg 0.23 Al 1.29 Si 3.57 S 3.25 Cl 0.12 K 0.07 Ca 0.35 Cr 0.17 Fe 1.83 Mo 0.77 Total 100.00

[0100] The dried clogging material is subjected to the above step 2 burning treatment to obtain the total weight of organic matter, sulfur and other volatile substances and carbonates in the clogging material.

[0101] The clogging material after drying was subjected to the extraction treatment of step 3 above to obtain the total amount of organic matter and the total amount of inorganic matter. The analysis results are shown in Table 4.

[0102] Table 4 Component content after preliminary separation of clogging material

[0103]

[0104]

[0105] The clogging material was subjected to extraction in different proportions of methanol:acetone = 3:1 to 10:1, a binary mixture of methanol and ethyl acetate with a mass ratio of ethyl acetate:methanol = 3:1 to 10:1, and a binary mixture of ethyl acetate and diethyl ether with a mass ratio of ethyl acetate:diethyl ether = 3:1 to 10:1. The extraction results are as follows:

[0106] Table 5 Extraction solvent ratio and extraction effect

[0107] Ratio Ethyl acetate: methanol Methanol: acetone Ethyl acetate: diethyl ether 3:1 30.9 33.1 26.4 5:1 26.2 34.2 22.5 7:1 21.4 35.7 17.8 10:1 18.5 36.2 15.2

[0108] Note: The above proportions are mass ratios, and the effect data are extraction weight percentages.

[0109] From the results, it can be seen that the preferred ethyl acetate:methanol ratio of 3:1 can achieve good extraction effect; the extraction amount only increases by 3.1% when the methanol:acetone ratio is from 3:1 to 10:1, and considering factors such as effect, economy, and safety, a ratio of 3:1 is more appropriate; when the ethyl acetate:diethyl ether ratio is from 3:1 to 10:1, the extraction amount decreases significantly, and the extraction capacity under the condition of 3:1 is lower than that of ethyl acetate:methanol under the same condition.

[0110] (3) Accurate analysis of component content of clogging material

[0111] After the clogging material after drying was subjected to the extraction treatment of step 3 above, the first extraction liquid, the second extraction liquid, and the third extraction liquid were subjected to gel filtration, ion exchange, and chromatographic separation under a separation pressure of less than 5 MPa to obtain each single-component organic matter, which was subjected to infrared characterization analysis.

[0112] 1) Organic matter characterization analysis

[0113] Petroleum ether extract: The clogging material after drying was a brown oily substance with a mass percentage of 16.4%, and infrared analysis showed that it was mineral oil, as shown in Figure 14 and 15 .

[0114] Ethyl acetate (containing methanol) extract: After the clogging material was extracted with petroleum ether, the insoluble matter was extracted with ethyl acetate (containing methanol), and after drying, it was a brownish yellow paste with a mass percentage of 30.9%. Spectral analysis showed that it was mainly adipic acid polyester substances, as shown inFigure 16 and 17 as shown.

[0115] The extract:plug mixture (methanol:acetone) was 5:1. The insoluble residue after extraction with petroleum ether and ethyl acetate was extracted with a mixture of methanol:acetone, and after drying, a yellow paste was obtained with a mass percentage of 2.2%. Spectral analysis showed that the main substance was a polyester, such as Figure 18 and 19 as shown.

[0116] 2) Inorganic matter characterization analysis

[0117] Acid-insoluble matter: the inorganic matter after separation by extraction with an organic solvent, dried and weighed, was the inorganic matter content, 25.3%. After dissolution with hydrochloric acid and filtration, the residue was the acid-insoluble matter, which was dried and analyzed by infrared spectroscopy, which showed that the main substance was a silicon compound, with a content of 11.4%, as shown in Figure 20 .

[0118] 3) Overall characterization analysis of the plug

[0119] The plug was analyzed by infrared spectroscopy as a test sample. The infrared spectrum showed that the organic matter of the sample was mainly mineral oil, polyacrylate, and ester crosslinking material, and the inorganic matter was iron compound, silicon compound, and a small amount of carbonate and chloride, as shown in Figure 13 .

[0120] Based on the above and the analysis results, the composition of the plug was analyzed, and the composition of the inorganic matter was inferred, as shown in Table 6.

[0121] Table 6: Content of each component of the plug

[0122]

[0123] (4) Source inference

[0124] Based on the fingerprint spectrum analysis results and the production situation of the well, the organic matter in the plug was mainly derived from the injected mineral oil and sealing grease, and the inorganic matter was mainly derived from the mud and formation particles. The main reason for the formation was that the organic additive residues wrapped the formation particles and mud solid phase to form adhesive materials. For the plugging situation of the well, a targeted plug-breaking agent was recommended, with a dissolution rate of 87%. The appearance of the original sample and the dissolved sample is shown in Figure 21 and 22 .

[0125] (5) Plugging construction

[0126] By the 25 inorganic + organic cleaning fluid unblocking, the downhole tubing and near wellbore plugging can be effectively removed, the oil pressure is restored from 13.9 MPa to 36.8 MPa, the daily production is restored from 570,000 cubic meters to 820,000 cubic meters, which shows that the analysis technology is accurate, the analysis time is controlled within 7 working days; the targeted unblocking fluid system is further optimized, and the obvious unblocking effect is obtained. The field construction parameters are shown in Table 7, and the acidizing and fracturing construction is shown in Figure 23 .

[0127] Table 7 Field construction parameters

[0128]

[0129] The above specific embodiments further illustrate the purposes, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method of oil and gas well production analysis, characterized by, The method comprises the following steps: Step 1: sample drying treatment: the weight difference before and after drying is taken as the water content of the sample; Step 2: burning separation treatment: the sample after drying in step 1 is burned in the low-temperature section and the high-temperature section respectively, the weight loss of the sample in the low-temperature section includes the total amount of organic matter, sulfur and other volatile substances, and the weight loss of the sample in the high-temperature section includes the weight of carbon dioxide lost by the conversion of carbonates into oxides; the dried sample is subjected to elemental quantitative characterization; Step 3: extraction and purification treatment: the sample after drying in step 1 is extracted and separated by different polar organic solvents to obtain organic matter and inorganic matter; the organic matter and the inorganic matter are characterized qualitatively and quantitatively to obtain the content of the organic matter and the content of the inorganic matter; the extracted organic matter is analyzed to determine the content of the organic matter, the functional groups, the types and contents of insoluble substances after burning in different extraction stages; Step 4: fingerprint library comparison treatment: the characterization results in step 3 are compared with the fingerprint library I and the fingerprint library II, and the similarity of the output sample is matched by using the characteristic parameters of Euclidean distance, correlation coefficient and included angle cosine calculation; Step 5: output product inference treatment: the type of the output product and the weight percentage of the water content, the organic matter and the inorganic matter of the output product are determined; The numerical values of the Euclidean distance, the correlation coefficient and the included angle cosine calculation are calculated according to the weight of 30%, 30% and 40% to obtain the numerical values as the characteristic parameters for judging the similarity, and the similarity of the fingerprint library I is greater than 90% and the similarity of the fingerprint library II is greater than 85%, which is judged as being consistent with the fingerprint library data of the detected output product; The fingerprint library I refers to the chemical additive fingerprint library, and the fingerprint library II refers to the output product composition fingerprint library; In step 2, the temperature range of the low-temperature section is 550±10℃, and the temperature range of the high-temperature section is 950±10℃.

2. A method of oil and gas well production analysis according to claim 1, characterized in that, In step 3, the dried output product is first extracted by using an organic solvent with small polarity, then the polarity of the organic solvent is gradually increased for extraction, and finally all the organic matter is extracted and separated.

3. A method of oil and gas well effluent analysis according to claim 2 wherein, In step 3, the output product is weighed, soaked in an organic solvent with the smallest polarity for 2h-6h, then stirred and centrifuged; the upper liquid is taken out, the polarity of the organic solvent is increased for continuous extraction, and the process is repeated for 3-6 times.

4. A method of oil and gas well effluent analysis according to claim 1 or 2, characterised in that, In step 3, the organic solvent includes one or more mixtures of ethylnitrile, petroleum ether, methanol, ethanol, acetone, ethyl acetate and diethyl ether.

5. A method of oil and gas well production analysis according to claim 4, wherein, In step 3, the organic solvent includes a binary mixture of methanol and acetone, and / or a binary mixture of methanol and ethyl acetate, and / or a binary mixture of ethyl acetate and diethyl ether.

6. A method of oil and gas well effluent analysis according to claim 5 wherein, In step 3, in the binary mixture of methanol and acetone, the mass ratio of methanol:acetone is 3:1-10:1; in the binary mixture of methanol and ethyl acetate, the mass ratio of ethyl acetate:methanol is 3:1-10:1; and in the binary mixture of ethyl acetate and diethyl ether, the mass ratio of ethyl acetate:diethyl ether is 3:1-10:

1.

7. The method of claim 1 wherein, In step 3, the organic mixture obtained after extraction with different organic solvents is separated by gel filtration, ion exchange and chromatography under a pressure of less than 5 MPa to obtain single-component organic substances, and the organic mixture and the single-component organic substances are subjected to qualitative and quantitative characterization analysis.

8. The method of claim 1 wherein, In step 3, the inorganic substances obtained after separation by organic solvent extraction are dissolved in an acid solution to obtain acid-soluble inorganic substances and acid-insoluble inorganic substances, and the acid-soluble inorganic substances and the acid-insoluble inorganic substances are subjected to qualitative and quantitative characterization analysis. The acid solution is a mixed solution of hydrochloric acid with a mass concentration of 15-25% or nitric acid with a mass concentration of 50-70%, or a mixed solution of hydrochloric acid and nitric acid in a volume ratio of 3:

1.

9. The method of claim 1 wherein, The fingerprint library I and the fingerprint library II are constructed based on the following detection methods: spectroscopy, chromatography, mass spectrometry and energy spectrum method; the spectroscopy includes ultraviolet, infrared, nuclear magnetic resonance and X-ray diffraction; the chromatography includes thin layer chromatography, high performance liquid chromatography and high performance capillary electrophoresis.

10. The method of claim 1 wherein, The chemical additives include chemical additives for drilling mud, completion chemical additives, reservoir reconstruction chemical additives, foam drainage chemical additives, enhanced production chemical additives, oil production chemical agents and water injection well chemical additives.

11. The method of claim 1 wherein, In step 4, the similarity of the characteristic variables is calculated by using three parameters of Euclidean distance, correlation coefficient and cosine of the included angle.

12. A method of oil and gas well effluent analysis according to claim 11 wherein, The calculation formula of the Euclidean distance is shown in formula (1): （1）； In formula (1), X ik represents the ith additive and the pre-separation product sample, the kth characteristic variable, wherein k = 1, 2,..., m; X rk represents the mean vector of the characteristic peaks of the standard fingerprint library I or the fingerprint library II, the kth characteristic variable, wherein k = 1, 2,..., m.

13. The method of claim 11, wherein: The calculation formula of the correlation coefficient is shown in formula (2): （2）； In formula (2), X ik represents the i-th additive and the k-th characteristic variable value of the pre-separation product sample, wherein k = 1, 2, …, m; X i represents the average value of all variables of the i-th sample; X r represents the average value of all variables of the characteristic peaks of the standard fingerprint library I or the fingerprint library II, X rk represents the k-th characteristic variable value of the characteristic peaks of the standard fingerprint library I or the fingerprint library II, wherein k = 1, 2, …, m.

14. The method of claim 11, wherein, The calculation formula of the cosine of the included angle is shown in formula (3) （3）； In formula (3), X ik represents the i-th additive and the k-th characteristic variable value of the characteristic variable of the pre-separation product sample, wherein k = 1, 2,..., m; X rk represents the k-th characteristic variable value of the characteristic peak of the standard fingerprint library I or the fingerprint library II, wherein k = 1, 2,..., m.

15. A method of oil and gas well effluent analysis according to any one of claims 11 to 14, characterised in that, The characteristic variables include peak area, peak height and retention time of the characterization analysis spectrum. The main parameters for information intercommunication of the fingerprint library I and the fingerprint library II are the values calculated by the Euclidean distance, the correlation coefficient and the cosine of the included angle of the main peak height, the characteristic peak area and the retention time, so as to realize information intercommunication search and fast and accurate matching.

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