A method for testing shale oil and gas content parameters

Abstract

The present application relates to the technical field of shale oil and gas reservoir exploration, and particularly relates to a method for testing shale oil and gas content parameters, which comprises taking a core just out of a barrel as an original sample, desorbing the original sample, recording total desorbed gas G ad and obtaining a desorbed sample; preparing a frozen sample and a normal-temperature sample based on the desorbed sample, using the frozen sample and the normal-temperature sample for pyrolysis test, obtaining corresponding hydrocarbon content parameter group S at a set temperature based on the pyrolysis test; combining the total desorbed gas G ad and the hydrocarbon content parameter group S to a corresponding oil and gas content calculation formula to obtain relevant parameters of oil and gas content. According to the characteristics of the substances contained in the core, the technical scheme formulates the steps of sample desorption, sample preservation and sample pyrolysis, and can test the oil and gas content in the medium-high maturity shale oil and gas reservoir sample at the same time. Compared with the prior art, the technical scheme considers more comprehensive problems and can ensure that the test result is accurate and reliable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of shale oil and gas reservoir exploration, and particularly relates to a shale oil and gas content parameter testing method. BACKGROUND

[0002] At present, unconventional oil and gas resources have realized large-scale development, among which shale oil and gas is expected to become the main force for increasing reserves and production of crude oil and natural gas. In the exploration and evaluation of shale oil and gas reservoirs, oil content is a basic parameter for predicting the resource potential and an important reference for in-depth study of shale oil and gas enrichment mechanism.

[0003] For middle-high maturity shale reservoirs, just after entering the gas generation stage from the oil generation window, the reservoirs contain a certain amount of gaseous hydrocarbons and crude oil, and both should be quantitatively evaluated when evaluating the resource potential of the reservoirs, and the quantification of gas-oil ratio has certain reference significance for evaluating and predicting the oil mobility in shale oil reservoirs. At present, according to the 'Shale Gas Content Determination Method' (SY / T6940-2020), the gas content of high-over mature marine shale reservoirs cannot be tested, and the oil content cannot be tested. The oiliness evaluation methods include chloroform asphalt "A", rock pyrolysis method and nuclear magnetic resonance testing method, etc. When these methods are used to characterize the content of hydrocarbons in the reservoir, the rock samples are not specially treated, and the content of light hydrocarbon components in the middle-high maturity shale reservoirs is high and volatile, so the content of gaseous hydrocarbons in the sample and the content of light components in the crude oil cannot be accurately measured.

[0004] In order to accurately measure the amount of crude oil in the reservoir, the low-temperature freezing method is currently used to preserve and crush the sample to avoid the loss of hydrocarbons in the core sample during the surface transfer process, and then a small amount of powder sample is taken to measure the content of hydrocarbons according to the 'Rock Pyrolysis Analysis' (GB / T18602-2012) for rock pyrolysis temperature programming. This method can avoid the loss of part of the light liquid hydrocarbons to a certain extent, but it cannot distinguish the content of residual gaseous hydrocarbons in the test sample and calculate the amount of lost gas, and it also cannot estimate the recoverable oil content in the sample. Therefore, it is urgent to establish a method for quickly, continuously and accurately testing the gas content and recoverable oil content in the sample. SUMMARY

[0005] In view of the above problems in the prior art, the present application provides a shale oil and gas content parameter testing method, which can quickly, continuously and accurately quantitatively characterize the gas content and recoverable oil content in middle-high maturity shale, and solves the technical problems that the content of gaseous hydrocarbons cannot be tested and the content of recoverable oil, bound oil and solid hydrocarbons cannot be distinguished in the prior art.

[0006] The present application is realized by adopting the following technical solutions:

[0007] A shale oil and gas content parameter testing method, comprising the following steps:

[0008] S1, sample acquisition: taking the core just out of the barrel as the original sample, and after measuring and recording the mass of the original sample, the original sample is sealed in the desorption tank of the shale gas content measuring device;

[0009] S2, sample desorption: the desorption tank containing the original sample is placed in the constant temperature device, so that the original sample is desorbed at constant temperature, and after the sample desorption is completed, the total desorption gas G is recorded ad , and the desorbed sample is obtained;

[0010] S3, sample preservation: two pieces are knocked off from the desorbed sample as pyrolysis samples; one piece of pyrolysis sample is placed in liquid nitrogen for frozen preservation as a frozen sample; the other piece of pyrolysis sample is preserved at room temperature as a room temperature sample;

[0011] S4, sample pyrolysis: the frozen sample and the room temperature sample are used for pyrolysis test, and based on the pyrolysis test, a corresponding hydrocarbon content parameter group S is obtained at a set temperature;

[0012] S5, oil and gas content calculation: the total desorption gas G ad and the hydrocarbon content parameter group S are combined in a corresponding oil and gas content calculation formula to obtain related parameters of the oil and gas content.

[0013] Preferably, the sample desorption comprises the following steps:

[0014] S21, preparing the constant temperature device, after adjusting the temperature in the constant temperature device to the drilling fluid circulation temperature, the desorption tank containing the original sample is placed in the constant temperature device;

[0015] S22, setting the gas amount detection time based on the shale gas content measuring device;

[0016] S23, the shale gas content measuring device intermittently detects and records the desorption gas amount of the desorption tank according to the set gas amount detection time, and simultaneously obtains a corresponding desorption rate V 解 based on the detected desorption gas amount;

[0017] S24, judging whether the desorption rate V 解 is less than the allowed minimum rate V t ; if not, return to S23, and if yes, end the sample desorption;

[0018] S25, detecting and recording the total desorption gas G ad using the shale gas content measuring device;

[0019] S26, opening the desorption tank and taking out the desorbed core as the desorbed sample.

[0020] Preferably, in the S22, the setting gas content detection time comprises: setting the shale gas content measuring device to count every 5 minutes in the first hour of sample desorption, every 10 minutes in the second hour, every 15 minutes in the third hour, and every 30 minutes after the third hour.

[0021] Preferably, in the S23, the minimum speed V t is 3cm 3 / 30min.

[0022] Preferably, in the process of pyrolysis of the sample, the pyrolysis test comprises the following steps:

[0023] S41, preparing the pyrolysis instrument and setting the working parameters of the pyrolysis instrument, including pyrolysis temperature and constant temperature time, that is, corresponding to the time t1, t2, t3, t4 at the formation temperature, 350℃, 450℃ and 600℃ in turn;

[0024] S42, crushing two pyrolysis samples and respectively taking a part of each to the pyrolysis instrument for pyrolysis, and recording the hydrocarbon content parameter group S in the process of pyrolysis; the hydrocarbon content parameter group S includes the hydrocarbon content S0, S 1-1 , S 1-2 2 measured after the constant temperature t1, t2, t3, t4 at the formation temperature, 350℃, 450℃ and 600℃ of the frozen sample and the normal temperature sample respectively, and the hydrocarbon content S0 * , S 1-1 * , S 1-2 * , S2 * ;

[0025] S43, mixing the remaining frozen sample powder and the normal temperature sample powder in S42, and obtaining a mixed sample after uniform mixing;

[0026] S44, taking the mixed sample into the soxhlet extractor, and washing the mixed sample with dichloromethane to obtain an extraction sample I after oil washing;

[0027] S45, putting the extraction sample I into an oven to make the dichloromethane in the extraction sample I volatilize completely to obtain an extraction sample II;

[0028] S46, taking the extraction sample II into the pyrolysis instrument to perform pyrolysis, and recording the pyrolysis gas volume parameters in the process of pyrolysis, i.e. recording the hydrocarbon content S0', S1', S2' measured after the constant temperatures t1, t2, t3, t4 corresponding to the formation temperature, 350℃, 450℃ and 600℃ 1-1 ’、S 1-2 ’、S2’,and adding the hydrocarbon content S0', S1', S2' into the hydrocarbon content parameter group S. 1-1 ’、S 1-2 ’、S2’.

[0029] Preferably, in the S41, the working parameters of the pyrolysis instrument are set to include setting the heating rate, and the heating rate is 50℃ / min.

[0030] Preferably, in the S41, t1=t2=t3=1min, and t4=2min.

[0031] Preferably, the oil and gas content calculation includes gas content calculation, and the gas content calculation includes the following steps:

[0032] S51, obtaining the lost gas volume G ls based on the formula G lost =V t / m ls ; wherein V lost is the lost gas volume determined by the USBM direct method.

[0033] S52, based on the hydrocarbon content S0 of the frozen sample in the S42, and combining the heat value conversion relationship G S0 =S0 / 0.717; wherein the hydrocarbon content S0 is also the heat release gas hydrocarbon content, and the heat release gas hydrocarbon content is converted into the natural gas content G S0 according to the aforementioned heat value conversion relationship.

[0034] S53, obtaining the gas content G in the rock according to the total desorbed gas volume G ad , the lost gas volume G ls and the natural gas content G S0 , i.e. G=G S0 +G ad +G ls .

[0035] Preferably, the oil and gas content calculation includes obtaining the recoverable oil content S y , i.e. S y =S 1-1 .

[0036] Preferably, the oil and gas content calculation obtains the bound oil content S s , i.e. S s =S 1-2 * +S2* -S2’.

[0037] Preferably, the oil and gas content calculation includes calculating the gas oil ratio GOR, i.e. GOR = (G ad+ G ls+ G S0 ) / (S y +S s ).

[0038] Preferably, the oil and gas content calculation includes obtaining the solid hydrocarbon content S g , i.e. S g =S2’.

[0039] The beneficial technical effects brought by the present application are:

[0040] 1. The technical solution combines the gas content test and rock pyrolysis experiment principles to formulate a shale oil and gas content test method. According to the characteristics of the substances contained in the core, the sample desorption, sample preservation and sample pyrolysis steps are formulated. Based on this, the oil and gas content in the medium-high maturity shale oil and gas reservoir sample can be tested at the same time. Compared with the prior art, the problems considered by the technical solution are more comprehensive, and the test result is accurate and reliable.

[0041] 2. The technical solution can obtain the gas content and oil content at the same time. Based on this, the gas oil ratio can be further obtained, which provides evaluation basis for reservoir crude oil mobility evaluation.

[0042] 3. The present application avoids the escape of light components of crude oil contained in medium-high maturity samples in the conventional (normal temperature) indoor environment and the sample crushing process, so that the oil content analysis result is more real, thereby greatly improving the accuracy of the oil content determination of medium-high maturity samples.

[0043] 4. The present application uses the evaporation and cracking temperature of different occurrence state crude oil and different component hydrocarbons to set the pyrolysis experiment temperature ladder, calculates the actual recoverable oil content, adsorbed oil content and solid hydrocarbon content in the sample, and provides more effective evaluation parameters for shale oil reservoir favorable section selection and resource quantity calculation.

[0044] 5. The present application obtains frozen samples, normal temperature samples and extracted samples, carries out pyrolysis experiments on the same depth samples with different preservation, sample preparation and pretreatment methods, establishes the calculation formula of the recoverable oil content, the bound oil content and the solid hydrocarbon content according to the occurrence of the recoverable oil, the bound oil and the solid hydrocarbon under different sample experimental conditions, which is more accurate than the value obtained under one sample experimental condition.

[0045] 6. According to the escaping rule of hydrocarbons, the correction formula of conventional pyrolysis parameters is established by linear curve fitting of the parameter values of the frozen sample and the normal temperature sample in the rock pyrolysis process, the parameter contents of the conventional sampling sample before the hydrocarbon escaping are calculated, and the recoverable oil content is calculated, so that the number and test time of the frozen sampling sample can be reduced, and the accuracy of the recoverable oil content calculation is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 For a preferred implementation flowchart of the technical solution. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical scheme and advantages of the application clearer, the technical scheme in the application will be described clearly and completely in combination with the drawings in the application. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments.

[0048] Therefore, the following detailed description of the application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the application without creative labor are within the scope of protection of the application.

[0049] Embodiment 1

[0050] The embodiment discloses a testing method for shale oil and gas content parameters, which is a preferred embodiment of the application and comprises the following steps.

[0051] S1, obtaining a sample: taking the core just out of the barrel as an original sample, and measuring and recording the mass m of the original sample t Then, the original sample is sealed in a desorption tank of a shale gas content measuring device. In this process, the length of the original sample is determined according to the capacity size of the desorption tank, for example, the length of the original sample can be controlled to 25±5 cm according to the currently used desorption tank.

[0052] S2, sample desorption: placing the desorption tank containing the original sample into a constant temperature device, so that the original sample is desorbed at a constant temperature, recording the total desorbed gas amount G ad (unit cm 3 / g), and obtaining the desorbed sample (i.e. the solid material remaining in the desorption tank). Wherein, G ad = V ad / m t , V ad represents the desorbed gas volume under standard conditions (20℃, 0.101325MPa), and V ad = (293.15P mXV d ) / [0.101325x(273.15+T m )];P m represents atmospheric pressure, V d represents desorption gas volume, T m represents ambient temperature.

[0053] S3, sample preservation: two pieces are knocked from the desorption sample as pyrolysis samples; one piece of pyrolysis sample is put into liquid nitrogen for frozen preservation (to lock the volatile matter in the desorption sample), as a frozen sample; the other piece of pyrolysis sample is preserved at normal temperature, as a normal temperature sample.

[0054] S4, sample pyrolysis: the frozen sample and the normal temperature sample are used for pyrolysis test, and corresponding hydrocarbon content parameter group S is obtained based on the pyrolysis test at a set temperature. Specifically, the pyrolysis gas volume parameter in the hydrocarbon content parameter group S is specifically a hydrocarbon content parameter.

[0055] S5, oil and gas bearing volume calculation: the total desorption gas volume G ad and the hydrocarbon content parameter group S are combined in a corresponding oil and gas bearing volume calculation formula to obtain related parameters of the oil and gas bearing volume.

[0056] Example 2

[0057] The embodiment discloses a shale oil and gas bearing volume parameter testing method, which is a preferred embodiment of the present application, i.e. Example 1, sample desorption includes the following steps:

[0058] S21, prepare the constant temperature device, and after adjusting the temperature in the constant temperature device to the drilling fluid circulation temperature, place the desorption tank containing the original sample into the constant temperature device.

[0059] S22, desorption refers to the reverse process of adsorption, which is an operation of separating the absorbed gas from the absorbent (corresponding to the core in the present technical solution). In the process of desorption, as the adsorbed gas in the core becomes less and less, the desorption rate will also gradually decrease. Based on this, whether the desorption has been completed can be judged according to the way of obtaining the desorption rate. The simplest way to obtain the rate is to obtain the desorption gas volume in different time periods. Based on this, the shale gas content measuring device can be set to detect the gas volume detection time.

[0060] S23, the shale gas content measuring device intermittently detects and records the desorption gas volume of the desorption tank according to the set gas volume detection time, and simultaneously obtains the corresponding desorption rate V 解 .

[0061] S24, based on the special structure inside the core, some gas will always remain inside the core. Therefore, the desorption rate V 解Drop to zero, which brings difficulty to determine whether desorption has been completed, for this, first preset a minimum allowable rate V t , determine whether the desorption rate V 解 is less than the minimum allowable rate V t ; if not, return to S23, if yes, the sample desorption can be ended.

[0062] S25, after the end of sample desorption, the shale gas content measuring device is used to detect and record the total desorption gas G ad , more specifically, the total desorption gas G ad is the volume of natural gas contained in the unit mass of core under standard state (20℃, 0.101325MPa), that is, the unit of total desorption gas G ad is cm 3 / g.

[0063] S26, open the desorption tank and take out the desorbed core as a desorption sample.

[0064] Example 3

[0065] This embodiment discloses a shale oil and gas content parameter testing method, which is a preferred embodiment of the present application, that is, the sample desorption in example 1 includes the following steps:

[0066] This embodiment discloses a shale oil and gas content parameter testing method, which is a preferred embodiment of the present application, that is, the sample desorption in example 1 includes the following steps:

[0067] S21, prepare a constant temperature device, adjust the temperature in the constant temperature device to the drilling fluid circulating temperature, and then put the desorption tank containing the original sample into the constant temperature device.

[0068] S22, set the gas detection time by the shale gas content measuring device. Based on the characteristics that the desorption rate is getting slower and slower, it is not meaningful to detect the gas quantity many times in a period of time in the later stage of desorption, and it will also increase the data processing amount, based on this, the gas detection time is set based on the characteristics that the desorption rate is getting slower and slower, that is, the shale gas content measuring device is set to count once every 5 minutes in the first hour of sample desorption, once every 10 minutes in the second hour, once every 15 minutes in the third hour, and once every 30 minutes after the third hour.

[0069] S23, the shale gas content measuring device intermittently detects and records the desorption gas of the desorption tank according to the set gas detection time, and obtains the corresponding desorption rate V 解 based on the detected desorption gas, the desorption rate V 解 may be the average desorption rate in each counting time interval.

[0070] S24, based on the special structure inside the core, some gas will always remain inside, so the desorption rate V 解 drops to zero, which makes it difficult to determine whether the desorption has been completed, for this, a minimum allowable rate V t may be first preset, and then it is determined whether the desorption rate V 解 is less than the minimum allowable rate V t ; if not, return to S23, if yes, the sample desorption can be ended; wherein the minimum allowable rate V t is 3cm 3 / 30min.

[0071] S25, after the sample desorption is completed, the shale gas content measuring device is used to detect and record the volume of natural gas contained in the unit mass of core under standard conditions (20℃, 0.101325MPa), that is, the total desorption gas G ad , unit cm 3 / g.

[0072] S26, open the desorption tank and take out the desorbed core as a desorption sample.

[0073] Example 4

[0074] The embodiment discloses a shale oil and gas content parameter testing method, as a preferred embodiment of the present application, comprising the following steps:

[0075] S1, obtain the sample: take the core just out of the barrel as the original sample, and after measuring and recording the mass m t of the original sample, seal the original sample in the desorption tank of the shale gas content measuring device.

[0076] S2, sample desorption: place the desorption tank containing the original sample into the constant temperature device, so that the original sample is desorbed at constant temperature, and after the sample desorption is completed, record the volume of natural gas contained in the unit mass of core under standard conditions (20℃, 0.101325MPa), that is, the total desorption gas G ad (unit cm 3 / g).

[0077] S3, sample preservation: knock off two pieces of the desorption sample as pyrolysis samples; one piece of the pyrolysis sample is placed in liquid nitrogen for frozen preservation as a frozen sample, which can ensure that the volatile matter is completely locked in the desorption sample; the other piece of the pyrolysis sample is preserved at room temperature as a room temperature sample.

[0078] S4, sample pyrolysis: the frozen sample and the normal temperature sample are used for pyrolysis test, and the corresponding hydrocarbon content parameter group S is obtained based on the pyrolysis test at the set temperature. Specifically, the pyrolysis gas amount parameter in the hydrocarbon content parameter group S is specifically the hydrocarbon content parameter.

[0079] The pyrolysis test includes the following steps:

[0080] S41, preparing the pyrolysis instrument, and setting the working parameters of the pyrolysis instrument, including the pyrolysis temperature and the constant temperature time, that is, the constant temperature t1, t2, t3, t4 time corresponding to the formation temperature (that is, the temperature of the original sample originally in the bottom layer), 350℃, 450℃ and 600℃ in turn; specifically, t1=t2=t3=1min, t4=2min, that is, the internal temperature in the pyrolysis instrument is constant t1=1min after reaching the formation temperature, the internal temperature in the pyrolysis instrument is constant t2=1min after reaching 350℃, the internal temperature in the pyrolysis instrument is constant t3=1min after reaching 450℃, and the internal temperature in the pyrolysis instrument is constant t4=2min after reaching 600℃.

[0081] S42, crushing the two pyrolysis samples (100 mesh or less), and then taking a part (100±5mg) of each into the pyrolysis instrument for pyrolysis (specifically, the frozen sample is sealed and crushed in a frozen sealed crushing instrument, and the normal temperature sample is crushed in a non-sealed crushing manner), and recording the hydrocarbon content parameter group S in the process of pyrolysis; the hydrocarbon content parameter group S includes the hydrocarbon content parameter of the frozen sample and the hydrocarbon content parameter of the normal temperature sample.

[0082] The hydrocarbon content parameter of the frozen sample includes:

[0083] S0: the detected hydrocarbon content per unit mass of core in the process of pyrolysis of the frozen sample after the pyrolysis instrument is constant t1 after reaching the formation temperature, unit: mg / g;

[0084] S 1-1 : the detected hydrocarbon content per unit mass of core in the process of pyrolysis of the frozen sample after the pyrolysis instrument is constant t2 after reaching 350℃, the hydrocarbon content here is the hydrocarbon content pyrolyzed in the process of heating from the formation temperature to 350℃ and constant t2, unit: mg / g;

[0085] S 1-2 : the detected hydrocarbon content per unit mass of core in the process of pyrolysis of the frozen sample after the pyrolysis instrument is constant t3 after reaching 450℃, the hydrocarbon content here is the hydrocarbon content pyrolyzed in the process of heating from 350℃ to 450℃ and constant t3, unit: mg / g;

[0086] S2: the hydrocarbon content in the unit mass of the core sample detected by the pyrolysis instrument after reaching 600℃ and constant temperature t4 during the pyrolysis of the frozen sample, wherein the hydrocarbon content is the hydrocarbon content pyrolyzed during the process of rising from 450℃ to 600℃ and constant temperature t3, in mg / g.

[0087] The hydrocarbon content parameters of the normal temperature sample include:

[0088] S0 * : the hydrocarbon content in the unit mass of the core sample detected by the pyrolysis instrument after reaching the formation temperature and constant temperature t1 during the pyrolysis of the normal temperature sample, in mg / g;

[0089] S 1-1 * : the hydrocarbon content in the unit mass of the core sample detected by the pyrolysis instrument after reaching 350℃ and constant temperature t2 during the pyrolysis of the normal temperature sample, wherein the hydrocarbon content is the hydrocarbon content pyrolyzed during the process of rising from the formation temperature to 350℃ and constant temperature t2, in mg / g;

[0090] S 1-2 * : the hydrocarbon content in the unit mass of the core sample detected by the pyrolysis instrument after reaching 450℃ and constant temperature t3 during the pyrolysis of the normal temperature sample, wherein the hydrocarbon content is the hydrocarbon content pyrolyzed during the process of rising from 350℃ to 450℃ and constant temperature t3, in mg / g;

[0091] S2 * : the hydrocarbon content in the unit mass of the core sample detected by the pyrolysis instrument after reaching 600℃ and constant temperature t4 during the pyrolysis of the normal temperature sample, wherein the hydrocarbon content is the hydrocarbon content pyrolyzed during the process of rising from 450℃ to 600℃ and constant temperature t3, in mg / g.

[0092] S43, the frozen sample powder and the normal temperature sample powder remaining in S42 are mixed, and a mixed sample is obtained after uniform mixing.

[0093] S44, the mixed sample (100±5mg) is loaded into a Soxhlet extractor, and the mixed sample is washed and treated (extracted) by dichloromethane, and the mixed sample after the oil washing treatment is used as the extraction sample I. The extraction can be ended when the fluorescence of the solvent dropped into the mixed sample is below level 3.

[0094] S45, the extraction sample I is placed into an oven, and the dichloromethane in the extraction sample I is completely volatilized to obtain an extraction sample II;

[0095] S46, Take the extracted sample II and place it into a pyrolysis apparatus for pyrolysis. Record the pyrolysis gas volume parameters during the pyrolysis process, that is, record the hydrocarbon content S0' and S at formation temperature, 350℃, 450℃ and 600℃, corresponding to isothermal t1, t2, t3 and t4. 1-1 '、S 1-2 S2', and the hydrocarbon content S0', S 1-1 '、S 1-2 ' and S2' are added to the hydrocarbon content parameter group S. Wherein:

[0096] S0': The hydrocarbon content detected per unit mass core during the pyrolysis of extracted sample II after the pyrolysis instrument reaches the formation temperature and is kept at a constant temperature t1, in mg / g.

[0097] S 1-1 ': During the pyrolysis of extracted sample II, the hydrocarbon content detected per unit mass of core after the pyrolysis instrument reaches 350℃ and is kept at a constant temperature for t2 is the hydrocarbon content of the pyrolysis during the process of raising the formation temperature to 350℃ and keeping it at a constant temperature for t2, in mg / g.

[0098] S 1-2 ': During the pyrolysis of sample II, the hydrocarbon content detected per unit mass of core after the pyrolysis instrument reaches 450℃ and is held at a constant temperature for t3. The hydrocarbon content here is the hydrocarbon content pyrolyzed during the process of heating from 350℃ to 450℃ and holding at a constant temperature for t3, in mg / g.

[0099] S2': The hydrocarbon content detected per unit mass of core sample II during pyrolysis, after the pyrolysis instrument reaches 600℃ and is held at a constant temperature for t4. The hydrocarbon content here is the hydrocarbon content pyrolyzed during the process of heating from 450℃ to 600℃ and holding at a constant temperature for t3, in mg / g.

[0100] S5, Calculation of oil and gas content: Calculate the total desorbed gas content G ad The hydrocarbon content parameter set S is combined with the corresponding oil and gas content calculation formula to obtain relevant parameters of oil and gas content. It should be noted that the foregoing content description refers to the hydrocarbon content parameter set S including hydrocarbon content parameters S0 and S2. 1-1 S 1-2 S2, S0 * S 1-1 * S 1-2 * S2 * S0', S 1-1 '、S 1-2S2', the data are recorded to ensure the completeness of the pyrolysis test data, to understand the specific conditions of sample pyrolysis, and to facilitate the analysis of the pyrolysis properties of the core in the later stage, and not all hydrocarbon content parameters are involved in the calculation of the related parameters obtained by the technical scheme.

[0101] Further, according to the change of the pyrolysis temperature of the pyrolysis instrument required to be set in S41, it can be seen that the pyrolysis instrument has a temperature rising process, based on this, the working parameters of the pyrolysis instrument also include setting the temperature rising rate, and the temperature rising rate is 50℃ / min.

[0102] Example 5

[0103] The embodiment discloses a shale oil and gas content parameter testing method, which is a preferred embodiment of the present application, i.e. in example 4, the oil and gas content calculation includes gas content calculation, and the gas content calculation includes the following steps:

[0104] S51, based on the formula Gls=V lost / m t Obtain the lost gas amount G ls ; wherein V lost is the lost gas volume, determined by the USBM (United States Bureau of Mines) direct method, with the accumulated desorption volume under standard conditions as the ordinate and the square root of the desorption time as the abscissa, the absolute value of the intercept of the reverse extension line with the ordinate axis in the desorption gas volume and square root of desorption time graph is defined as the lost gas.

[0105] S52, based on the hydrocarbon content S0 of the frozen sample in S42, combined with the heat value conversion relationship G S0 =S0 / 0.717; wherein the hydrocarbon content S0 is also the pyrolysis gas hydrocarbon content, according to the aforementioned heat value conversion relationship, the pyrolysis gas hydrocarbon content is converted into the natural gas content G S0 , the unit is cm 3 / g. It should be noted that 0.717 kg / m 3 is the methane density at normal temperature and pressure, and S0 is mainly composed of methane gas, so the methane gas density is used instead of the gaseous hydrocarbon density of S0 here.

[0106] S53, according to the total desorption gas amount G ad , the lost gas amount G ls and the natural gas content G S0 , the gas content G in the rock is obtained, that is, G=G S0 +G ad +G ls , the unit is cm 3 / g.

[0107] Further, the oil and gas bearing volume calculation includes obtaining the recoverable oil content S y , i.e. y S 1-1 .

[0108] Further, the oil and gas bearing volume calculation includes obtaining the bound oil content S s , i.e. s S 1-2 * +S2 * -S2’.

[0109] Further, the oil and gas bearing volume calculation includes calculating the gas oil ratio GOR, i.e. GOR = (G ad+ G ls+ G S0 ) / (S y +S s ).

[0110] Further, the oil and gas bearing volume calculation includes obtaining the solid hydrocarbon content S g , i.e. g S2’.

[0111] The principle involved in the foregoing calculation includes: shale oil in different occurrence states has different molecular thermal volatilization capacity, for a medium-high maturity shale oil reservoir, the produced crude oil is mainly light-medium oil component, and the evaporation temperature thereof is between the formation temperature and 350°C, and the thermal release hydrocarbon chromatographic characteristics in this temperature range are similar to the chromatographic characteristics of the crude oil, thus S 1-1 characterizes the recoverable oil content. The bound oil is mainly macromolecular heavy hydrocarbon, resin asphaltene component, and light-medium oil adsorbed in the micropores and nanometer pores of kerogen and clay minerals, and the evaporation, cracking and thermal desorption temperature thereof is mainly between 350°C and 450°C, but the cracking temperature of high-wax hydrocarbon and other such macromolecular bound oil adsorbed in the micropores and nanometer pores of kerogen and clay minerals is above 450°C, thus, by using the principle of similar phase solubility, dichloromethane is used to extract the light-heavy oil component in the sample, and the kerogen (solid hydrocarbon) in the remaining sample, and the kerogen degradation and hydrocarbon generation temperature needs to be above 450°C, thus S2’ characterizes the solid hydrocarbon content. Thus, the kerogen and bound hydrocarbon content above 450°C can be distinguished, S 1-2 * +S2 * -S2’ is the bound oil content.

[0112] Example 6

[0113] This embodiment discloses a method for testing shale oil and gas content parameters. As a preferred embodiment of the invention, specifically in Embodiment 5, hundreds of raw samples may be collected from a single wellbore. If each raw sample involves a pyrolysis test of frozen samples, the workload of shale oil and gas content testing would be significantly increased. Therefore, to reduce the workload, a subset (e.g., 10) of the raw samples are selected to participate in the pyrolysis test of frozen samples. Then, a correlation scatter plot is created using the parameter values ​​(hydrocarbon content parameters) obtained from the freeze-pyrolysis and room-temperature pyrolysis experiments at the same temperature range. A linear regression model is then used to fit the scatter plot, establishing a correction formula for the room-temperature pyrolysis parameters. The S0 value can be obtained from the room-temperature pyrolysis experiment (pyrolysis test of room-temperature samples). * S 1-1 * S 1-2 * S2 * , will S0 * S 1-1 * S 1-2 * S2 * Substituting these values ​​into the correction formula yields the corresponding freeze-pyrolysis (pyrolysis of frozen samples) values ​​S0 and S2. 1-1 S 1-2 S2.

Claims

1. A method of testing a shale oil and gas content parameter, characterized in that, The method comprises the following steps: S1, obtaining sample: taking the core just out of the barrel as the original sample, and measuring and recording the mass m of the original sample t After that, the original sample is sealed in the desorption tank of the shale gas content measuring device. S2, sample desorption: the desorption tank containing the original sample is placed in the constant temperature device, so that the original sample is subjected to sample desorption at constant temperature, and after the sample desorption is completed, the total desorption gas volume G is recorded ad , and the desorbed sample is obtained; S3, sample preservation: two pieces of the desorbed sample are knocked off as pyrolysis samples; one piece of the pyrolysis sample is placed in liquid nitrogen for cryopreservation as a frozen sample; the other piece of the pyrolysis sample is preserved at room temperature as a room temperature sample; S4, sample pyrolysis: the frozen sample and the room temperature sample are used for pyrolysis test, and a corresponding hydrocarbon content parameter group S is obtained at a set temperature based on the pyrolysis test; wherein the pyrolysis test comprises the following steps: S41, a pyrolysis instrument is prepared, and working parameters of the pyrolysis instrument are set, including pyrolysis temperature and constant temperature time, that is, the constant temperature t1, t2, t3 and t4 time corresponding to the formation temperature, 350 DEG C, 450 DEG C and 600 DEG C in turn; S42, after crushing the two pyrolysis samples, a part of each is put into a pyrolysis instrument for pyrolysis, and the hydrocarbon content parameter group S is recorded during the pyrolysis; the hydrocarbon content parameter group S includes the hydrocarbon content S0, S1, S2 and S3 measured after the frozen samples are kept at the formation temperature, 350℃, 450℃ and 600℃ respectively, corresponding to the constant temperatures t1, t2, t3 and t4 1-1 , S 1-2 , S2, and the hydrocarbon content S0 * , S 1-1 * , S 1-2 * , S2 * ; S43, the remaining frozen sample powder and the room temperature sample powder in S42 are mixed, and a mixed sample is obtained after uniform mixing; S44, the mixed sample is loaded into a soxhlet extractor, and the mixed sample is washed with dichloromethane to obtain an extracted sample I; The calculation of the gas content comprises the following steps: S46, Take the extracted sample II and place it into a pyrolysis apparatus for pyrolysis. Record the pyrolysis gas volume parameters during the pyrolysis process, that is, record the hydrocarbon content S0' and S at formation temperature, 350℃, 450℃ and 600℃, corresponding to isothermal t1, t2, t3 and t4. 1-1 '、S 1-2 S2', and the hydrocarbon content S0', S 1-1 '、S 1-2 Add ' and S2' to the hydrocarbon content parameter group S; S5, gas and oil content calculation: total desorbed gas amount G ad and the hydrocarbon content parameter group S are combined in the corresponding gas and oil content calculation formula to obtain the relevant parameters of the gas and oil content, including gas content, oil content, gas-oil ratio and solid hydrocarbon content; The calculation of the oil content includes the calculation of the recoverable oil content S y and the bound oil content S s ; wherein S y = S 1-1 , S s = S 1-2 * + S2 * - S2' The gas-oil ratio GOR = (G ad+ G ls+ G S0 ) / (S y +S s ); said solid hydrocarbon content S g = S2'; The sample desorption comprises the following steps: S51, based on formula G ls =V lost / m t Obtain the loss gas volume G ls ; wherein V lost is the loss gas volume, determined using the USBM direct method; S52, based on the hydrocarbon content S0 of the frozen sample in S42, combining the heat value conversion relationship G S0 = S0 / 0.717; wherein the hydrocarbon content S0 is also the heat release gaseous hydrocarbon content, which is converted into the natural gas content G according to the aforementioned heat value conversion relationship S0 ; S53, the total gas amount G is obtained from the total desorbed gas amount G ad , the lost gas amount G ls , and the natural gas content G S0 The gas content G in the rock is obtained, i.e. G = G S0 + G ad + G ls .

2. The method of claim 1, wherein: S21, a constant temperature device is prepared, and the temperature in the constant temperature device is adjusted to the drilling fluid circulation temperature, then the desorption tank loaded with the original sample is placed in the constant temperature device; S22, the gas content determination device is set to detect the gas content; S26, the desorption tank is opened, and the desorbed core is taken out as a desorbed sample. S23, the shale gas content determination device intermittently detects and records the desorption gas amount of the desorption tank according to the set gas amount detection time, and obtains the corresponding desorption rate V based on the detected desorption gas amount 解 ; S24, determining desorption rate V 解 whether less than the allowed minimum rate V t ; if not, return to S23, if yes, end sample desorption; S25, detecting and recording total desorbed gas amount G by shale gas content determination device ad ; In S22, the gas content detection time is set as follows: the shale gas content determination device is set to count every 5 minutes in the first hour of sample desorption, every 10 minutes in the second hour, every 15 minutes in the third hour, and every 30 minutes after the third hour.

3. The method of claim 2, wherein: In S41, the working parameters of the pyrolysis instrument are set, and the heating rate is also set, and the heating rate is 50 DEG C / min.

4. The method of claim 2, wherein: S23, the minimum rate V t 3 cm 3 / 30 min.

5. The method of claim 1, wherein: In S41, t1=t2=t3=1min, and t4=2min.

6. The method of claim 1, wherein: ​

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