A method and device for determining the carbon content of a full range of rocks

Abstract

The invention discloses a method and device for determining the full range of carbon content in rocks. The method comprises: S1, crushing the sample in a sealed vacuum, collecting gas at 100°C, and detecting hydrocarbon carbon FHC1 in kerogen and pores; S2, weighing a portion of the crushed sample in S1, collecting gas at 300°C, and detecting kerogen adsorbed hydrocarbons and pore hydrocarbon carbon FHC2; S3, crushing the remaining crushed sample in S2 in a sealed vacuum, weighing a portion of the crushed sample, pyrolyzing it at 850°C to detect organic carbon NTOC, and simultaneously oxidizing it at 850°C to detect total carbon C; S4, extracting the remaining crushed sample in S3 by supercritical carbon dioxide to detect kerogen heavy hydrocarbons and inclusion hydrocarbon carbon SIC; S5, quantitatively injecting hydrochloric acid into the remaining crushed sample in S4 under a sealed vacuum condition for dissolution, detecting carbonate mineral carbon CC by using a pressure increment value; detecting organic acid salt hydrocarbon carbon OAC by solution neutralization; S6, taking the remaining slag sample after hydrochloric acid dissolution in S5, pyrolyzing it at 850°C to detect kerogen hydrocarbon carbon KHC; and S7, calculating and outputting the results. This method has the advantages of low cost, simple operation and high detection efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of petroleum geological exploration, and in particular to a method and device for determining the carbon content of a full range of rocks. Background Art

[0002] Rocks rich in hydrocarbon-generating organic matter can be roughly divided into three types: siliceous, carbonate, and clay. The three are often referred to as mudstone or carbonate rock. Modern oil and gas geological theory believes that dark mudstones containing siliceous and clay (including mudstone and shale) are the main strata for oil and gas generation in basins around the world. Measuring the total organic carbon (TOC) content of organic matter in mudstone can be used to determine its hydrocarbon generation capacity. The latest research represented by Liu Wenhui (A New Interpretation of the Theory of Hydrocarbon Generation from Organic Matter in Marine Carbonate Strata in China, Petroleum Exploration and Development, 2017, 44(1): 155-164) shows that carbonate rocks dominated by carbonate minerals or containing a certain amount of clay minerals are also important strata for oil and gas generation in certain specific areas. The organic acid salts in them are hydrocarbon-generating substances with high hydrocarbon conversion rates. Long-term exploration and research have demonstrated that mudstones from different formations with the same total organic carbon (TOC) content can vary significantly in the amount of effective organic matter truly involved in hydrocarbon generation. Type I organic matter, primarily composed of algae and fungi, is predominantly hydrocarbon-generating, with very little non-hydrocarbon-generating organic matter (so-called dead carbon or ineffective carbon, RC) remaining. In contrast, Type III organic matter, primarily composed of higher plants, is largely incapable of hydrocarbon generation. Furthermore, given the same TOC value within the same formation, samples from higher thermal evolution have more dead carbon RC than those from lower thermal evolution. Consequently, two major controversies remain: the organic carbon parameter that truly determines hydrocarbon generation in rocks and the type of hydrocarbon-generating rock. Clearly, both the traditional use of TOC as a proxy for source rock identification and the resolution of these two controversies rely primarily on determining lithology through the carbon content of carbonate minerals and determining the contribution of hydrocarbon-generating materials by distinguishing carbon from organic acid salt minerals, carbon from organic matter encapsulated in inorganic minerals, and the effective carbon content of conventional TOC.

[0003] Traditional methods for identifying source rocks rely on acid dissolution of inorganic minerals followed by pyrolysis to determine total organic carbon (TOC). Effective source rocks are identified when the TOC value reaches a certain value. This method, exemplified by the national standard GBT1945-2003, "Standard for the Determination of Total Organic Carbon in Sedimentary Rocks," pre-treats rock samples with acid before feeding them into a high-temperature pyrolysis furnace in a carbon-sulfur analyzer. TOC is measured using an infrared or hydrogen ion flame detector. The limitations of this method are as mentioned above. Firstly, it fails to distinguish between effective carbon (PC), which contributes to hydrocarbon generation, and dead carbon (RC), which does not. Secondly, during the pre-treatment process, most organic acid salts and some organic matter encapsulated by inorganic minerals are lost through acid dissolution of carbonate minerals and washed away with water. The remaining organic matter, encapsulated by hydrochloric acid-insoluble minerals such as siliceous minerals, cannot be measured at conventional pyrolysis temperatures. Ultimately, conventional TOC values ​​exclude both organic acid salts and all mineral-encapsulated organic matter. This makes the evaluation of hydrocarbon-generating materials in source rocks, particularly carbonate rocks, difficult.

[0004] Although Liu Quanyou (Science China: Earth Sciences, 2013, 43(12): 1975-1983) gave a separation process for dispersed organic matter (chloroform bitumen extracts), kerogen organic acids, and organic acid salts obtained after rock acidification in rock samples, the contribution of organic matter from different sources to hydrocarbon generation was not quantitatively given due to the uncertainty of the carbon number of organic acids.

[0005] The patent "Pretreatment device and control method for analyzing the total organic carbon content in sedimentary rocks" (application number 201610471225.4, authorization announcement number CN106198134B) announced a set of devices for controlling temperature, controlling reagent addition, and controlling pH in order to improve the efficiency of rock acid hydrolysis and standardize the work process. Ultimately, the rock residue after removing inorganic carbon and washing out hydrocarbons can be obtained for preparing samples for traditional total organic carbon determination.

[0006] The patent "A method for quantitative analysis of organic carbon in carbonate rocks" (application number CN201510272740.5, authorization announcement number CN104931310B) and Liu Peng (New method for measuring organic matter abundance in carbonate rocks, Acta Sedimentologica Sinica, 2016, 34(1): 200-206) proposed using montmorillonite to thicken the rock acid solution, allowing it to enter a carbon-sulfur analyzer along with the rock residue for carbon element analysis to determine the total organic carbon content, including organic acid salts, in the rock acid solution. This method actually solves the problem of liquid sampling, but does not solve the problem of determining organic matter encapsulated in acid-insoluble minerals, nor does it distinguish between effective carbon and dead carbon in the total organic carbon, let alone the determination of the carbon content of carbonate minerals. Similarly, the patent "Method for restoring the original organic matter abundance of mud carbonate rocks and its application" (publication number CN114199911A, application number 202010878987.2) discloses a method of using montmorillonite as a rock acid solution absorbent and mixing it with insoluble rock slag to detect the total hydrocarbon organic carbon (including the total amount of organic acid salts and traditional total organic carbon TOC) in mud carbonate rock samples.

[0007] The patent "A method for evaluating the total organic carbon content in sedimentary rocks" (application number CN201710750188.5, authorization announcement number CN107687986B) provides a method and formula for calculating total organic carbon based on various parameters obtained from rock pyrolysis analysis. The national standard GB / T18602-2012 on "Rock Pyrolysis Analysis" and the instruction manual of the Rock-Eal6 rock pyrolyzer sold by the French Petroleum Institute publish the parameters obtained from rock pyrolysis and the calculation formulas for total organic carbon TOC, effective carbon PC and dead carbon RC using these parameters. Since the pyrolysis parameter curves are overlapping and divided according to temperature segments, the method of calculating organic carbon using pyrolysis parameters is artificial and cannot distinguish the organic carbon content of organic acid salts. During rock pyrolysis operations, the free hydrocarbon S1 content of the sample must also be controlled to reduce the impact on the judgment of S2 and pyrolysis peak temperature. The peak of organic matter encapsulated in the inorganic mineral lattice will also overlap with the carbonate rock peak, bringing interference to the values ​​of various pyrolysis parameters, which will ultimately cause uncertainty in the calculated value of organic carbon.

[0008] The patent "A filtration device for removing organic acid salts in water" (application number CN202010500327.0, publication number CN202010500327.0) discloses a device structure with charged paper and filter elements as the main materials. The device disclosed in this patent can remove organic acid salts in water, but it cannot collect organic acid salts without loss, nor can it quantify organic acid salts, and the degree of sample contamination is uncontrollable.

[0009] The patent "A soil organic carbon content measuring instrument" (application number CN201822220317.2, publication number CN209247769U) is based on the chemical reaction principle of acid and organic matter reacting to produce carbon dioxide, and sets up a set of acidification and carbon dioxide acquisition devices. This method cannot distinguish between inorganic carbon and organic carbon. In addition, carbon dioxide dissolves in water and is easily lost, and it cannot meet the detection accuracy requirements of low-carbon samples.

[0010] The existing technologies disclosed above can only analyze one of the following: organic carbon, pyrolysis, carbonate content, or organic acid salt content, failing to comprehensively analyze source rock lithology and various hydrocarbon source carbon types. The free hydrocarbon S1 and pyrolysis peak temperature Tmax parameters used in pyrolysis analysis are also unreliable. Therefore, from a scientific perspective, existing technologies suffer from fragmented functionality, single detection parameters, and inaccurate and incomplete analysis, failing to meet the needs of cutting-edge source rock geochemical research. This leads to high overall costs. Summary of the Invention

[0011] The present invention aims to provide a method and apparatus for determining the carbon content of a full range of rocks. This method or apparatus can help experimental analysts and geological researchers determine the contents of inorganic mineral carbon, organic carbon encapsulated by inorganic minerals, traditional total organic carbon, and effective carbon in various types of rocks, including source rocks, as well as conventional parameters for rock pyrolysis analysis. This method is low-cost, simple to operate, and highly efficient, completing and acquiring multiple data parameters and tasks that would require multiple batches of testing using existing methods. This method provides support and means for systematic research on major issues such as rock diagenesis, the content of effective hydrocarbon-generating materials, and determining the validity of source rocks.

[0012] To achieve the above object, the present invention provides the following technical solutions:

[0013] The present invention provides a method for determining the carbon content of a full range of rocks, the method comprising the following steps:

[0014] Step S1, crushing the sample in a sealed vacuum chamber, collecting gas at 100°C, and detecting hydrocarbon carbon FHC1 in kerogen and pores;

[0015] Step S2, weighing part of the crushed sample in step S1, collecting gas at 300°C, and detecting kerogen adsorbed hydrocarbons and pore hydrocarbon carbon FHC2;

[0016] Step S3, the remaining crushed sample in step S2 is sealed and vacuum crushed, a portion of the crushed sample is weighed, and pyrolysis is performed at 850°C to detect organic carbon (NTOC), and oxidation is performed at 850°C to detect total carbon (C);

[0017] Step S4, extracting the remaining crushed sample in step S3 by supercritical carbon dioxide to detect kerogen heavy hydrocarbons and inclusion hydrocarbon carbon (SIC);

[0018] Step S5: Under closed vacuum conditions, quantitatively inject hydrochloric acid into the remaining crushed sample in step S4 for dissolution, and use the pressure increment value to detect carbonate rock mineral carbon CC;

[0019] Step S6, neutralizing the acid solution in step S5 with an alkaline solution, and detecting organic acid salt hydrocarbon carbon (OAC);

[0020] Step S7: taking the residual slag sample after hydrochloric acid dissolution in step S6, and pyrolyzing it at 850° C. to detect kerogen hydrocarbon carbon (KHC);

[0021] Step S8: Calculation and result output.

[0022] In a possible implementation, in step S1, the particle size of the crushed sample is ≤5 mm.

[0023] In a possible embodiment, in step S3, the particle size of the crushed sample is 4.0 to 6.0 μm.

[0024] In a possible embodiment, in step S5, the injection amount of hydrochloric acid is in a volume ratio of carbon dioxide: hydrochloric acid ≥ 1:7.

[0025] In one possible embodiment, the calculation expression of the relevant carbon content is as follows:

[0026] The parameter for determining lithology is new mineral carbon MC, MC = CC + C-NTOC, in %;

[0027] The parameter that contributes to hydrocarbon generation is determined as new effective carbon NPC, NPC = FHC1 + FHC2 + SIC + KHC + OAC, the unit is %;

[0028] The organic carbon parameter that does not contribute to hydrocarbon generation is determined as the new residual carbon NRC, NRC = NTOC-SIC-KHC-OAC, the unit is %;

[0029] The parameter for determining total organic carbon in rocks is the new total organic carbon TC, TC = NTOC + FHC1 + FHC2, in %; the traditional total organic carbon parameter TOC = NTOC - OAC - FHC1, in %

[0030] Determine the parameter of rock free hydrocarbon S1 = (FHC1 + FHC2) * 100 / 8.3, the unit is mg / g rock;

[0031] The parameter for determining rock pyrolysis hydrocarbons is S2 = NTOC*100 / 8.3, with the unit being mg / g rock.

[0032] The present invention also provides a device for determining the carbon content of a full range of rocks, the device comprising: a sample processing and separation module, a fluid product processing module, a detection module and a computer control and result output module; wherein,

[0033] The upper portion of the inlet tube sleeve port on the sample processing and separation module is connected to the air pump group and flow metering pump of the fluid product processing module for sealed vacuum sample crushing;

[0034] The extract collection box of the fluid product processing module is connected to the lower portion of the lower sample outlet sleeve of the sample processing and separation module, and is used to collect gas and inject hydrochloric acid;

[0035] The nitrogen inlet port of the detection module is connected to the air pump group of the fluid product processing module, and is used to detect kerogen and pore hydrocarbon carbon FHC1, detect kerogen adsorbed hydrocarbons and pore hydrocarbon carbon FHC2, detect total carbon C by oxidation at 850°C, detect kerogen heavy hydrocarbons and inclusion hydrocarbon carbon SIC, detect carbonate mineral carbon CC, detect organic acid salt hydrocarbon carbon OAC, and detect kerogen hydrocarbon carbon KHC by pyrolysis at 850°C;

[0036] The automatic control mainboard of the computer control and result output module is connected and communicated with the pyrolysis furnace and oxidation furnace of the detection module for calculation and result output.

[0037] In one possible embodiment, the sample processing and separation module includes an upper outer shell, a lower outer shell, a sealing ring, a grinding ball, a pressure gauge sleeve, an upper sample inlet sleeve and a lower sample outlet sleeve; wherein,

[0038] The inner shape of the upper and lower outer sleeves after being combined is an ellipsoid, and the outer shape is an octagonal body. The middle is connected by male and female threads, and a copper sealing ring is placed at the connection; grinding balls are placed inside;

[0039] The pressure gauge sleeve is in communication with the inner wall of the upper outer sleeve;

[0040] The upper sample injection tube sleeve is arranged above the upper outer sleeve and is provided with a first pneumatic valve;

[0041] The lower sample outlet pipe sleeve is arranged below the lower outer sleeve and is provided with a second pneumatic valve.

[0042] In one possible embodiment, the fluid product processing module includes an air pump group, a flow metering pump, an extract collection box and an acidified liquid neutralization tank; wherein,

[0043] The air pump group includes an air compression pump, a nitrogen cylinder and a carbon dioxide cylinder, which are connected to a flow metering pump;

[0044] The air compression pump of the air pump group is connected to both the first pneumatic valve and the second pneumatic valve;

[0045] The nitrogen cylinder and the carbon dioxide cylinder of the air pump group are connected to the upper sampling tube sleeve through a flow metering pump;

[0046] The extract collection box and the acidified liquid neutralization tank are both connected to the lower sample outlet pipe sleeve.

[0047] In a possible embodiment, the detection module includes a nitrogen inlet port, a sampling port, a pyrolysis furnace, an oxidation furnace, an oxygen inlet port and an infrared detector; wherein,

[0048] The pyrolysis furnace is connected to the oxidation furnace, and the lower end of the oxidation furnace is connected to the infrared detector;

[0049] The pyrolysis furnace is provided with a nitrogen inlet port and a sampling port, and the sampling port is provided with a third pneumatic valve;

[0050] The oxidation furnace is provided with an oxygen injection port.

[0051] In a possible implementation, the computer control and result output module includes an automation control mainboard, a data acquisition device, and a data processing software system; wherein,

[0052] The data processing software system is connected with the automation control mainboard and the data collector, and has programming software.

[0053] Technical effects and advantages of the present invention:

[0054] (1) The present invention is based on the simplest and most integrated device. Through specific operation experimental steps, it can systematically obtain carbon content parameters, traditional organic carbon parameters, and pyrolysis parameters of various sources of hydrocarbon source rocks, including organic acid salts, carbonate rocks, graphite, kerogen, etc., and thus judge the lithology, hydrocarbon generation potential, and thermal maturity of the hydrocarbon source rocks in a very comprehensive, systematic and accurate manner.

[0055] (2) This method and device can be used to evaluate the hydrocarbon generation capacity of low-TOC hydrocarbon sources that rely on early organic acid salts, and can also be used to determine the content of carbonate rocks and discover graphite element carbon deposits. It also makes up for the loss of free hydrocarbons and mineral-encapsulated hydrocarbons in conventional methods, thereby providing a most systematic solution for the integrated geochemical testing of source rocks and providing support for geochemical research and marine and terrestrial oil and gas exploration.

[0056] (3) This method can be used to determine the lithology of rock samples, determine the abundance of various organic matter involved in hydrocarbon generation, and fully judge the effectiveness of source rocks and the composition of hydrocarbon-generating organic matter. This method makes up for the shortcomings of existing methods such as incomplete testing, saving time and economic costs while providing a comprehensive understanding of rocks. This method will provide an economical, fast and effective source rock system testing method and device for oil and gas resource evaluation.

[0057] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 This is a schematic diagram of the main structure of a device for determining the carbon content of a full range of rocks according to an exemplary embodiment of the present invention;

[0059] Figure 2 A flow chart of a method for determining the carbon content of a full range of rocks according to an exemplary embodiment of the present invention;

[0060] In the figure, 101, upper outer sleeve; 102, lower outer sleeve; 103, sealing ring; 104, grinding ball; 105, pressure gauge sleeve; 106, upper sample inlet sleeve; 107, lower sample outlet sleeve; 108, first pneumatic valve; 109, second pneumatic valve; 201, air pump group; 202, flow metering pump; 203, extract collection box; 204, acidified liquid neutralization tank; 301, nitrogen inlet port; 302, sample inlet; 303, pyrolysis furnace; 304, oxidation furnace; 305, oxygen inlet port; 306, infrared detector; 307, third pneumatic valve; 401, automation control main board; 402, data acquisition unit; 403, data processing software system. DETAILED DESCRIPTION

[0061] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0062] Figure 1 This is a schematic diagram of the main structure of a device for determining the carbon content of a full range of rocks according to an exemplary embodiment of the present invention. Figure 1 As shown, the present invention discloses a device for determining the carbon content of a full range of rocks. The device is divided into four modules: a sample processing and separation module, a fluid product processing module, a detection module, and a computer control and result output module; wherein,

[0063] The sample processing and separation module mainly includes an upper outer jacket 101, a lower outer jacket 102, a sealing ring 103, a grinding ball 104, a pressure gauge sleeve 105, an upper sample inlet sleeve 106, and a lower sample outlet sleeve 107. The upper outer jacket 101 and the lower outer jacket 102 are made of KA4145 high-temperature and high-strength alloy steel to meet the temperature change range of -50 to 300°C within 30 minutes, while also being able to withstand the physical conditions of a high pressure of 40MPa and the requirements of hydrochloric acid corrosion. The outer shape of the upper outer jacket 101 and the lower outer jacket 102 after they are combined is an octagonal body, connected in the middle by male and female threads, and a copper sealing ring 103 is placed at the connection. The inner shape of the upper outer jacket 101 and the lower outer jacket 102 after they are combined is an ellipsoid, with an inner short axis length of 7cm, an outer short axis length of 8.4cm, and a volume of 245mL. The grinding ball 104 is made of KA4145 high-temperature and high-strength alloy steel. , the sphere has a diameter of 4 cm and a volume of 33.49 mL; the sealing ring 103 is T3 copper; the pressure gauge sleeve 105 is connected to the inner wall of the upper outer sleeve 101, and the pressure gauge range is 0.01~40 MPa; the upper sampling tube sleeve 106 is made of 316 stainless steel and is provided with a first pneumatic valve 108. The upper part of the tube mouth can be connected to the fluid product processing module air pump group 201, and can also be connected to the fluid flow metering pump 202 to provide the gas or hydrochloric acid used; the lower sampling tube sleeve 107 is made of 316 stainless steel and is provided with a second pneumatic valve 109. The lower part of the tube mouth can be connected to the liquid product processing module extract collection box 203.

[0064] The fluid product processing module includes an air pump group 201, a flow metering pump 202, an extract collection box 203 and an acidified liquid neutralization tank 204. The air pump group 201 includes a nitrogen cylinder, a carbon dioxide cylinder and an air compression pump, which is connected to the flow metering pump 202. The air compression pump is connected to each pneumatic valve and provides power for all pneumatic valves (i.e., the first pneumatic valve 108, the second pneumatic valve 109 and the third pneumatic valve 307); the flow metering pump 202 provides nitrogen, carbon dioxide and hydrochloric acid to the sample injection tube sleeve 106 on the sample processing and separation module in a quantitative manner. Specifically, the nitrogen cylinder and carbon dioxide cylinder in the air pump group are connected to the sample through the flow metering pump 202. The upper sampling sleeve 106 of the sample processing and separation module is connected, and hydrochloric acid enters the upper sampling sleeve 106 of the sample processing and separation module through the flow pump 202; the extract collection box 203 is a box tank that can maintain -20°C, which can keep the glassware and its contents at a low temperature, and the glassware is connected to the lower sampling sleeve 107 of the sample processing and separation module; the acidified liquid neutralization tank 204 is an acid-resistant silica gel tank or a glass tank, does not contain any organic material, and is also connected to the lower sampling sleeve 107 of the sample processing and separation module.

[0065] The detection module includes a nitrogen inlet port 301 , an injection port 302 , a pyrolysis furnace 303 , an oxidation furnace 304 , an oxygen inlet port 305 and an infrared detector 306 . The nitrogen inlet port 301 is connected to the nitrogen bottle of the air pump group 201; the sampling port 302 serves as the detection sampling port for gas and liquid products in any step and for processing liquid samples, and the sampling port 302 has a special third pneumatic valve 307; the pyrolysis furnace 303 can use existing products on the market, but the maximum temperature is required to reach 850°C; the pyrolysis furnace 303 is connected to the oxidation furnace 304; the oxidation furnace 304 has an oxygen sampling port 305; the oxidation furnace 304 can use existing products on the market, but the maximum temperature is required to reach 850°C; the lower end of the oxidation furnace 304 is connected to an infrared detector 306; the pyrolysis furnace 303 and the oxidation furnace 304 are both connected and communicated with the automatic control mainboard 401 of the computer control and result output module; the infrared detector 306 is connected and communicated with the data collector 402.

[0066] The computer control and result output module includes an automated control mainboard 401, a data acquisition unit 402, and a data processing software system 403. In addition to operating the various module components, the automated control mainboard 401 also controls the activation and deactivation of the first pneumatic valve 108, the second pneumatic valve 109, the third pneumatic valve 307, and the oxidation furnace 304. The data acquisition unit 402 has signal lines connected to the pressure gauge sleeve 105, the flow metering pump 202, and the infrared detector 306. The data processing software system 403 is connected to the automated control mainboard 401 and the data acquisition unit 402 and includes programming software to transmit automated control instructions, process and calculate data, and utilize the software for further calculations and result output.

[0067] Figure 2 A flow chart of a method for determining the carbon content of a full range of rocks according to an exemplary embodiment of the present invention is shown in FIG. Figure 2 As shown, the present invention also discloses a method for determining the carbon content of a full range of rocks, the method comprising the following steps:

[0068] Step S1: After sealing and vacuuming, crush the sample to less than 5 mm, collect gas at 100°C, and detect hydrocarbon carbon (FHC1) in kerogen and pores. The weighed block rock sample and grinding ball 104 are sequentially placed into the lower outer sleeve 102 of the sample processing and separation module. The sealing ring 103 and upper outer sleeve 101 are assembled, and the second pneumatic valve 109 of the lower sample outlet sleeve 107 is closed. Vacuum is then drawn from the upper sample inlet sleeve 106. The loaded sample processing and separation module is rotated 90° and laid upside down. The module is placed in an oscillator and oscillated for 30 seconds. The module is then returned to the original position and rapidly heated to 100°C. The pressure is stabilized and recorded. A small amount of gas sample is taken from the upper sample inlet sleeve 106 and injected into the inlet 302 of the detection module to detect hydrocarbon content. Combined with the recorded pressure values, the FHC1 content in kerogen and pores of the entire rock sample is further determined.

[0069] Step S2: Weigh a portion of the crushed sample, collect gas at 300°C, and detect kerogen-adsorbed hydrocarbons and pore hydrocarbon carbon FHC2. After completing step S1, cool to room temperature, open the upper outer jacket 101 and the lower outer jacket 102, weigh a certain amount of crushed sample, and inject it through the injection port 302 of the detection module. Set the pyrolysis temperature to 300°C, and detect the hydrocarbon content as kerogen-adsorbed hydrocarbons and pore hydrocarbon carbon FHC2;

[0070] Step S3: After sealing and vacuuming, the sample is crushed to 4.0-6.0 μm at low temperature, and then pyrolyzed at 850°C for detection of organic carbon (NTOC), and oxidized at 850°C for detection of total carbon (C). The remaining main crushed sample is cooled to -20°C together with the sample processing and separation module, and then crushed again according to step S1, with the oscillation time set to 1-3 minutes. A portion of the crushed sample is weighed, and the pyrolysis furnace 303 is set to 850°C, while the oxidation furnace 304 is closed and turned on, to detect organic carbon (NTOC). Another portion of the crushed sample is weighed, and the pyrolysis furnace 303 and oxidation furnace 304 are set to 850°C in series and turned on, to detect total carbon (C).

[0071] Step S4: 300° C., 30 MPa supercritical carbon dioxide extraction to detect kerogen heavy hydrocarbons and inclusion hydrocarbon carbon SIC. The sample remaining in the sample processing and separation module after secondary crushing is loaded into the sample processing and separation module according to step S1. After evacuation, 15.3 MPa of carbon dioxide is pumped in at room temperature and then heated to 300°C. After moderate shaking, the sample processing and separation module is cooled to room temperature and tilted at an angle of 30-60°. The second pneumatic valve 109 of the lower sample outlet sleeve 107 is opened, and the fluid is slowly introduced into the bottom of the volumetric flask containing dichloromethane in the extraction collection box 203, so that the hydrocarbons in the extract are fully dissolved and absorbed by the dichloromethane. The upper sample inlet sleeve 106 continues to pump 15.3 MPa of carbon dioxide at a low speed and maintains this pressure until the color of the dichloromethane solution no longer changes significantly. Montmorillonite powder is quantitatively added to the dichloromethane solution. After the dichloromethane evaporates to constant weight at room temperature, a small amount of the solid mixture is sampled and injected through the detection module inlet 302. The sample is passed through an 850°C pyrolysis furnace to obtain kerogen heavy hydrocarbons and inclusion hydrocarbon carbon (SIC).

[0072] Step S5: Under sealed vacuum conditions, quantitative hydrochloric acid is injected for dissolution, and the pressure increment is used to detect carbonate mineral carbon (CC). The solution is neutralized to detect organic acid salt hydrocarbon carbon (OAC). After step S4 is completed, the injection of carbon dioxide is stopped, the second pneumatic valve 109 of the lower sample outlet sleeve 107 is closed, vacuum is drawn from the outlet of the upper sample inlet sleeve 106, and the sample processing and separation module is cooled to room temperature. An excess amount of hydrochloric acid solution is injected using a flow metering pump 202 at a ratio of ≥1:7 (V / V). After the reaction is complete, the pressure gauge sleeve 105 is read, and the carbon dioxide generated is calculated based on the volume and pressure of the sample processing and separation module, which is the carbonate mineral carbon (CC). The acid solution is introduced into the acidified solution neutralization tank 204, and sodium hydroxide is added for neutralization and constant volume. A certain amount of the solution is then added to montmorillonite powder for thickening. The organic acid salt hydrocarbon carbon (OAC) is detected using the dual-operation mode of the pyrolysis furnace 303 and oxidation furnace 304 of the detection module.

[0073] Step S6: Take the residual slag sample after hydrochloric acid dissolution, pyrolyze it at 850° C., and detect kerogen hydrocarbon carbon (KHC).

[0074] Step S7: Calculate and output the result.

[0075] Among them, the calculation expression of relevant carbon content is as follows:

[0076] The parameter for determining lithology is new mineral carbon MC, MC = CC + C-NTOC, in %;

[0077] The parameter that contributes to hydrocarbon generation is determined as new effective carbon NPC, NPC = FHC1 + FHC2 + SIC + KHC + OAC, the unit is %;

[0078] The organic carbon parameter that does not contribute to hydrocarbon generation is determined as the new residual carbon NRC, NRC = NTOC-SIC-KHC-OAC, the unit is %;

[0079] The parameter for determining total organic carbon in rocks is the new total organic carbon TC, TC = NTOC + FHC1 + FHC2, in %; the traditional total organic carbon parameter TOC = NTOC - OAC - FHC1, in %

[0080] Determine the parameter of rock free hydrocarbon S1 = (FHC1 + FHC2) * 100 / 8.3, the unit is mg / g rock;

[0081] The parameter for determining rock pyrolysis hydrocarbons is S2 = NTOC*100 / 8.3, with the unit being mg / g rock.

[0082] It should be noted that the materials and sizes used in the present invention are the result of comprehensive consideration of price and performance in practice. The performance needs to consider high temperature and high pressure resistance, acid corrosion resistance, low creep, etc. Other materials and sizes with suitable price and performance are also applicable to the present invention.

[0083] The following is a detailed explanation based on the detection example of Cretaceous calcareous mudstone source rock samples in the Bongor Basin of Chad.

[0084] Step S1), initial collection and detection of volatile hydrocarbons in the sample. Take 20g of block sample with a particle size of 5-20mm (rock density is 2.0g / mL), put it into the lower jacket 102, place the grinding ball 104 and install the upper jacket 101; input the injection volume of 20g into the computer; close the second pneumatic valve 109, and vacuum the sample through the first pneumatic valve 108 for 30 minutes until the pressure gauge sleeve 105 shows less than 0.01MPa; place the assembled sample processing and separation module on a suitable oscillator, shake for 30 seconds to crush the sample to less than 5mm; perform the sample processing and separation module. The temperature is kept constant at 100°C, and the computer reads and records the pressure value P0 = 0.072 MPa of the pressure gauge sleeve 105. 5 mL of a gas sample at a pressure of 0.103 MPa is collected through the upper sampling tube sleeve 106 using a flow metering pump 202 for heat preservation. The sample is then loaded into the detection module using nitrogen. The detection module is set to close the pyrolysis furnace 303 and open the oxidation furnace 304. The carbon content of the detected gas is 0.109%. After conversion and calculation by the computer control and the result output module, the hydrocarbon carbon FHC1 in the kerogen and pores of the rock sample is obtained.

[0085] FHC1=0.109%*(245-33.49-20 / 2.0)*0.072 / (5×0.103) / 20=0.154%;

[0086] Step S2: Secondary collection and detection of free hydrocarbons in the sample. The sample processing and separation module is cooled to room temperature. A 1g rock sample is removed and placed into the pyrolysis furnace of the detection module. The pyrolysis furnace 303 is turned on and 300°C pyrolysis is initiated. The pyrolysis gas products are introduced into the oxidation furnace. The 300°C pyrolysis hydrocarbon carbon detection is completed. The computer displays a value of 0.408%. The computer control and result output module calculate the carbon value FHC2 of the rock sample's kerogen adsorbed hydrocarbons and pore hydrocarbons after 300°C pyrolysis using a formula.

[0087] FHC2=0.408% / 1=0.408%;

[0088] Step S3, secondary sample crushing and solid sample pyrolysis and oxidation carbon detection. The remaining 19g rock sample from the previous step is further sealed in the sample processing and separation module, vacuumed and cooled to -20°C, placed on a suitable oscillator again, and shaken for 60 seconds to crush the sample to about 5μm; take two samples weighing 1g, one of which is placed in the detection module, the pyrolysis furnace 303 is turned on, and 850°C pyrolysis is started. The pyrolysis gas products are introduced into the oxidation furnace 304 to complete the 850°C pyrolysis hydrocarbon carbon detection, and the computer display value is 7.215%; the other sample is placed in the detection module, the oxidation furnace 304 is turned on, and the carbon product detection after 850°C oxidation is started. The computer display value is 7.418%; the computer control and result output module are used to give the rock sample 850°C pyrolysis organic carbon NTOC and 850°C oxidation total carbon C through the calculation formula;

[0089] NTOC=7.215%;

[0090] C=7.418%.

[0091] Step S4, supercritical carbon dioxide extraction of kerogen heavy hydrocarbons and inclusion hydrocarbons, hydrocarbon carbon detection. Seal the remaining 17g rock sample in the previous step in the sample processing and separation module, after vacuuming, connect the upper pipe sleeve 106 and the flow metering pump 202, pump 15.3MPa carbon dioxide at room temperature, and then heat the sample to 300℃; after moderate shaking for 10 minutes, cool the sample processing and separation module to room temperature and place it at an angle of 30-60°; open the second pneumatic valve 109 of the lower sample sleeve 107, and slowly introduce the carbon dioxide extraction fluid into the bottom of the volumetric flask of the extraction collection box 203 filled with dichloromethane, so that the hydrocarbons in the extract are fully dissolved and absorbed by the dichloromethane. The upper sampling tube sleeve 106 continues to pump 15.3MPa of carbon dioxide at a low speed for 10 minutes until the color of the dichloromethane solution no longer changes significantly; 2g of montmorillonite powder is then added to the dichloromethane solution and stirred moderately. After the dichloromethane evaporates to a constant weight at room temperature, 1g of the montmorillonite powder sample is taken and injected through the sampling port 302 of the detection module. After passing through the 850°C pyrolysis furnace 303 and the oxidation furnace 304, the carbon content is detected to be 16.520%. The kerogen heavy hydrocarbons and inclusion hydrocarbon carbon of the original rock sample are given by the computer control and result output module through the calculation formula;

[0092] SIC=16.520%*2 / 1 / 17=1.944%.

[0093] Step S5: Hydrochloric acid dissolution to determine the carbonate mineral carbon content. The sample remaining in the sample processing and separation module in the previous step is further sealed and evacuated at room temperature. 10 mL of 1:7 (V / V) hydrochloric acid is then injected via a flow metering pump. The pressure gauge 105 reads a stable value of 0.62 MPa. The carbonate mineral carbon content CC of the original rock sample is then calculated using a formula controlled by the computer and output by the result module.

[0094] CC=0.62 / 0.103*(245-33.49-17 / 2.0-10) / 1000 / 22.4*12 / 17*100%=3.661%.

[0095] Step S6: Neutralize the acid solution and determine the organic acid salt hydrocarbon carbon content. The acid solution is introduced into the acidified liquid neutralization tank 204 via the lower sample outlet tube 107. The sample in the sample processing and separation module is rinsed three times with 10 mL of deionized water, and then the sample is combined into the acidified liquid neutralization tank 204. Sodium hydroxide is added, and the volume is adjusted to 50 mL after neutralization. 1 mL of the sample is injected through the detection module injection port 302 and passed through the 850°C oxidation furnace 304. The carbon content is detected to be 0.229%. The organic acid salt carbon content OAC is calculated by the computer control and result output module according to the formula.

[0096] OAC=0.229%*50 / 17=0.674%.

[0097] Step S7: Pyrolyze the slag sample at 850°C to determine the kerogen pyrolysis hydrocarbon carbon content. 0.1 g of the slag sample from the sample processing and separation module after the previous step is injected through the detection module inlet 302, passed through the 850°C pyrolysis furnace 303, and then introduced into the oxidation furnace 304. The carbon content is detected to be 0.364%. The kerogen pyrolysis hydrocarbon carbon content (KHC) is calculated using a formula in the computer control and result output module.

[0098] KHC=0.364% / 0.1=3.640%.

[0099] Step S8: Output of report results. Based on the results of the above steps, the data processing software system 403 of the computer control and result output module outputs parameter values ​​with geological significance:

[0100] The elemental carbon content of the rock sample EC = C-NTOC = 7.418% - 7.215% = 0.203%, with an effective value of 0.20%;

[0101] The total organic carbon content of the rock sample TC = NTOC + FHC1 + FHC2 = 7.215% + 0.154% + 0.408% = 7.777%, the effective value is 7.77%;

[0102] Rock effective carbon content NPC=FHC1+FHC2+SIC+KHC+OAC

[0103] =0.154%+0.408%+1.944%+3.640%+0.674%=6.82%, the effective value is 6.82%;

[0104] Rock residual carbon content NRC = NTOC-SIC-KHC-OAC

[0105] =7.215%-1.944%-3.640%-0.674%=0.957%, effective value is 0.95%; rock mineral carbon content MC=CC+EC=CC+C-NTOC

[0106] =3.661%+7.418%-7.215%=3.864%, the effective value is 3.86%;

[0107] The carbonate content of the rock is CC*100 / 12=3.661%*100 / 12=30.508%, and the effective value is 30.50%;

[0108] Traditional total organic carbon content of rock TOC = NTOC-OAC-FHC1

[0109] =7.215%-0.674%-0.154%=6.387%, the effective value is 6.38%;

[0110] Rock free hydrocarbon S1 = (FHC1 + FHC2) * 100 / 8.3

[0111] =(0.154%+0.408%)*100 / 8.3=6.771mg / g rock, the effective value is 6.77mg / g rock;

[0112] Rock pyrolysis hydrocarbon S2 = NTOC*100 / 8.3 = 7.215%*100 / 8.3 = 86.928 mg / g rock, and the effective value is 86.92 mg / g rock.

[0113] According to the process data of detecting organic carbon NTOC in the 850°C pyrolysis furnace in step (3), the temperature at the peak of pyrolysis hydrocarbons can be obtained, and the pyrolysis peak temperature parameter Tmax is obtained as 432°C.

[0114] In summary, the present invention utilizes a device design of three simple modules, and through specific operating steps, obtains parameter tests that cannot be achieved by existing instruments or cannot be fully achieved by existing instruments, and can combine the functions of multiple instruments, and the test parameters are doubled, so its efficiency is greatly improved, and the test time and economic cost are greatly reduced. In terms of applicability, it can not only realize rock pyrolysis analysis and organic carbon content analysis in the field of basic geochemical detection of source rocks, but can also be used for carbonate rock content analysis to determine rock types, and even elemental carbon testing can help discover graphite mines. Taking into account the free hydrocarbon volatilization during sample crushing that easily causes the loss of free hydrocarbons, the special device and steps of the present invention improve the accuracy of the parameter; the early steps remove the free hydrocarbons, so the obtained pyrolysis peak temperature parameter is more representative of the true thermal evolution degree of the rock than the value of the traditional pyrolysis method. In short, the characteristics of the present invention are that it starts from scientific research problems and has the characteristics of efficiently and systematically completing multiple analysis parameter indicators.

[0115] It should be noted that the present invention has no requirements for samples and is applicable to samples of various rock types such as mudstone, carbonate rock, gypsum salt rock, etc.; the operation and operating environment of the device require a scientific laboratory environment; the present invention is applicable to the fields of geological minerals, oil and gas exploration, especially the shale oil and gas field where more attention is paid to source rocks, and provides rock organic and inorganic chemical component analysis for the above fields; the present invention can combine the functions and uses of multiple instruments such as rock pyrolysis analysis, rock organic carbon content analysis, rock carbonate content analysis, and organic matter thermal maturity, can completely replace the test instrument, and can improve the accuracy of parameters such as free hydrocarbon S1 and organic matter abundance in pyrolysis analysis, so it has broad application prospects.

[0116] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for determining the carbon content of a full range of rocks, characterized in that: The method comprises the following steps: Step S1, crushing the sample in a sealed vacuum chamber, collecting gas at 100°C, and detecting hydrocarbon carbon FHC1 in kerogen and pores; Step S2, weighing part of the crushed sample in step S1, collecting gas at 300°C, and detecting kerogen adsorbed hydrocarbons and pore hydrocarbon carbon FHC2; Step S3, the remaining crushed sample in step S2 is sealed and vacuum crushed, a portion of the crushed sample is weighed, and organic carbon (NTOC) is detected by pyrolysis at 850°C, and total carbon (C) is detected by oxidation at 850°C; Step S4, extracting the remaining crushed sample in step S3 by supercritical carbon dioxide to detect kerogen heavy hydrocarbons and inclusion hydrocarbon carbon (SIC); Step S5: Under closed vacuum conditions, quantitatively inject hydrochloric acid into the remaining crushed sample in step S4 for dissolution, and use the pressure increment value to detect carbonate rock mineral carbon CC; Step S6, neutralizing the acid solution in step S5 with an alkaline solution, and detecting organic acid salt hydrocarbon carbon (OAC); Step S7: taking the residual slag sample after hydrochloric acid dissolution in step S5, and pyrolyzing it at 850° C. to detect kerogen hydrocarbon carbon (KHC); Step S8: Calculation and result output.

2. The method for determining the carbon content of a full range of rocks according to claim 1, characterized in that: In the step S1, the particle size of the crushed sample is ≤5 mm.

3. The method for determining the carbon content of a full range of rocks according to claim 1, characterized in that: In step S3, the particle size of the crushed sample is 4.0 to 6.0 μm.

4. The method for determining the carbon content of a full range of rocks according to claim 1, characterized in that: In step S5, the injection amount of hydrochloric acid is carbon dioxide: hydrochloric acid in a volume ratio of ≥1:

7.

5. A method for determining the carbon content of a full range of rocks according to any one of claims 1 to 4, characterized in that: The calculation expression of the relevant carbon content is as follows: The parameter for determining lithology is new mineral carbon MC, MC = CC + C-NTOC, in %; The parameter that contributes to hydrocarbon generation is determined as new effective carbon NPC, NPC = FHC1 + FHC2 + SIC + KHC + OAC, the unit is %; The organic carbon parameter that does not contribute to hydrocarbon generation is determined as new residual carbon NRC, NRC = NTOC-SIC-KHC-OAC, the unit is %; The parameter for determining rock total organic carbon is new total organic carbon TC, TC = NTOC + FHC1 + FHC2, the unit is %; Traditional total organic carbon parameter TOC = NTOC-OAC-FHC1, unit is % Determine the parameter of rock free hydrocarbon S1 = (FHC1 + FHC2) * 100 / 8.3, the unit is mg / g rock; The parameter for determining rock pyrolysis hydrocarbons is S2 = NTOC*100 / 8.3, with the unit being mg / g rock.

6. A device for determining the carbon content of a full range of rocks, characterized in that: The device includes: a sample processing and separation module, a fluid product processing module, a detection module and a computer control and result output module; wherein, The upper portion of the sample injection tube sleeve (106) on the sample processing and separation module is connected to the air pump group (201) and the flow metering pump (202) of the fluid product processing module for sealed vacuum sample crushing; The fluid product processing module extract collection box (203) is connected to the lower portion of the sample outlet pipe sleeve (107) of the sample processing and separation module for collecting gas and injecting hydrochloric acid; The nitrogen inlet port (301) of the detection module is connected to the air pump group (201) of the fluid product processing module, and is used to detect kerogen and pore hydrocarbon carbon FHC1, detect kerogen adsorbed hydrocarbons and pore hydrocarbon carbon FHC2, detect total carbon C by oxidation at 850°C, detect kerogen heavy hydrocarbons and inclusion hydrocarbon carbon SIC, detect carbonate mineral carbon CC, detect organic acid salt hydrocarbon carbon OAC, and detect kerogen hydrocarbon carbon KHC by pyrolysis at 850°C; The automatic control mainboard (401) of the computer control and result output module is connected and communicated with the pyrolysis furnace (303) and oxidation furnace (304) of the detection module for calculation and result output; wherein, The sample processing and separation module comprises an upper outer sleeve (101), a lower outer sleeve (102), a sealing ring (103), a grinding ball (104), a pressure gauge sleeve (105), an upper sample inlet sleeve (106) and a lower sample outlet sleeve (107); wherein, The upper outer sleeve (101) and the lower outer sleeve (102) are combined to form an ellipsoidal inner shape and an octagonal outer shape, connected in the middle by male and female threads, with a copper sealing ring (103) placed at the connection; and a grinding ball (104) is placed inside. The pressure gauge sleeve (105) is in communication with the inner wall of the upper outer sleeve (101); The upper sample injection tube sleeve (106) is arranged above the upper outer sleeve (101) and is provided with a first pneumatic valve (108); The lower sample outlet pipe sleeve (107) is arranged below the lower outer sleeve (102) and is provided with a second pneumatic valve (109); The fluid product processing module includes an air pump group (201), a flow metering pump (202), an extract collection box (203) and an acidified liquid neutralization tank (204); wherein, The air pump group (201) includes an air compression pump, a nitrogen cylinder and a carbon dioxide cylinder, and is connected to a flow metering pump (202); The air compression pump of the air pump group (201) is connected to both the first pneumatic valve (108) and the second pneumatic valve (109); The nitrogen bottle and the carbon dioxide bottle of the air pump group (201) are connected to the upper injection tube sleeve (106) through the flow metering pump (202); The extract collection box (203) and the acidified liquid neutralization tank (204) are both connected to the lower sample outlet pipe sleeve (107); The detection module includes a nitrogen inlet port (301), an injection port (302), a pyrolysis furnace (303), an oxidation furnace (304), an oxygen inlet port (305) and an infrared detector (306); wherein, The pyrolysis furnace (303) is connected to the oxidation furnace (304), and the lower end of the oxidation furnace (304) is connected to the infrared detector (306); The pyrolysis furnace (303) is provided with a nitrogen inlet port (301) and an injection port (302), and the injection port (302) is provided with a third pneumatic valve (307); The oxidation furnace (304) is provided with an oxygen injection port (305); The computer control and result output module includes an automation control mainboard (401), a data acquisition device (402) and a data processing software system (403); wherein, The data processing software system (403) is connected to the automation control mainboard (401) and the data collector (402), and has programming software.

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