Coal seam ash content rapid evaluation method based on while-drilling element logging

Abstract

The invention relates to the technical field of coal bed gas exploration and development, in particular to a coal bed ash content rapid evaluation method based on while-drilling element logging, which comprises the following steps: establishing an ash content calculation model; and calculating the ash content of the coal measure strata of the new well in the same block by using the ash content calculation model to obtain the ash content of the coal measure strata of the new well. According to the method, the ash content of the coal seam can be quickly calculated by using the while-drilling element logging data, and the defects of harsh construction conditions, high cost, low time efficiency and the like of an experimental method and a logging method are overcome. Through coal seam ash content calculation, coal seam horizontal well track optimization adjustment is effectively guided, and the drilling effect of the coal seam horizontal well is further improved; and meanwhile, other logging parameters can be combined to replace logging to complete evaluation of the horizontal well drilling and uncovering coal seam, reliable geological information is provided for a later reservoir transformation scheme, and an effective technical means is provided for low-cost and high-efficiency horizontal well development of coal bed gas.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coalbed methane exploration and development, and is a coalbed ash rapid evaluation method based on while-drilling element logging, and also includes a coalbed ash rapid evaluation device. BACKGROUND

[0002] As a clean energy, coalbed methane is widely used in industry, livelihood and transportation and other fields. With the increasing demand for clean energy and policy support, coalbed methane development and utilization technology has developed rapidly, and significant technical breakthroughs have been made in deep coal rock gas exploration, horizontal well drilling and fracturing, gradually realizing the efficient development of coalbed methane and steady increase in production. In view of the low-cost development and complex geological conditions of coalbed methane, scientific and technological research is intensified, technological innovation is promoted, and high-quality coalbed methane is sought, which puts forward new and higher requirements for the exploration and evaluation technology of coal reservoirs.

[0003] While-drilling coal quality evaluation is an important means to find high-quality coalbed methane reserves. By analyzing and measuring the moisture, ash content, volatile matter, fixed carbon and sulfur content of the drilled coal seam, the characteristics and evaluation parameters of the coal seam are obtained, among which the coal ash content is one of the most important indicators for measuring coal quality. It is also a key indicator for evaluating the quality of coalbed methane. Traditional coalbed methane detection mainly includes experimental method and logging method.

[0004] (1) Experimental method: The most direct and accurate method for coal seam quality evaluation is to detect and analyze the industrial components of coal seam samples in terms of particle size, volatile matter, ash content, fixed carbon, sulfur content, etc. However, due to the poor mechanical strength and fragility of coal seams, the core recovery rate is low, which limits the amount of corresponding experimental data, and the experimental procedure is complicated, time-consuming and costly, making it difficult to widely apply this method in coalbed methane horizontal well development. Experimental method requires coal core, but the cost of coring is high, and only the data and analysis data of the cored section can be obtained. The obtained coal reservoir information is less, and there is a lack of effective identification and interpretation method for the special rock composition characteristics of coal seams.

[0005] (2) Logging method: A multivariate regression coal seam industrial component prediction model of the cored well in the study area is constructed based on geophysical logging data, the relationships between logging density and ash content, acoustic wave and ash content, gamma and ash content, ash content and fixed carbon, and ash content + fixed carbon and volatile matter are analyzed, and a multivariate linear regression model is established to calculate related coal quality parameters. It has the characteristics of strong continuity and high reliability, and is widely used in coal quality evaluation. In the face of the requirements of large-scale development of coalbed methane horizontal wells, the shortcomings of logging method are more prominent. First, the construction difficulty of horizontal well logging is high, and the operation cost is high. Second, the time efficiency is low, and it cannot guide the real-time adjustment of horizontal well trajectory while drilling, and cannot guarantee the sweet spot drilling rate. Third, due to the easy collapse of coal seams, the wellbore conditions are poor, and there is a risk of logging instrument being stuck.

[0006] In order to adapt to the coalbed methane evaluation while drilling and the needs of horizontal well scale development, in view of the technical problems existing in the above experimental method and logging method, a new technical path and method must be explored. SUMMARY

[0007] The present application provides a coal seam ash rapid evaluation method based on element logging while drilling, which overcomes the shortcomings of the prior art, and effectively solves the problems of high construction requirement, high cost and low timeliness of coalbed methane detection methods such as experimental method and logging method.

[0008] Element logging is also known as X-ray fluorescence element logging, and its English abbreviation is XRF (X-Ray Fluorescence). At present, the data submitted by element logging includes 13 kinds of conventional elements and trace elements whose total mass accounts for more than 99%, including Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S and Cl.

[0009] One of the technical solutions of the present application is realized by the following measures: a coal seam ash rapid evaluation method based on element logging while drilling, comprising:

[0010] Firstly, the single-well standardization coefficient is calculated;

[0011] Secondly, the content logging data of each element of the single well is standardized respectively to obtain the content standardized value of each element after the single-well standardization coefficient is used for processing;

[0012] Thirdly, since the pure mudstone section and the pure sandstone section obtained by deposition in the oxidation environment almost do not contain organic matter, the inorganic component content is approximately equal to 100%, the pure mudstone section, the pure conglomerate section or the pure sandstone section in the well is taken as a characteristic section, the mineral element content of the characteristic section is calculated through the content standardized value of each cationic element corresponding to the characteristic section, and then the mineralization coefficient is calculated through the mineral element content of the characteristic section;

[0013] Fourthly, the mineral element content of the coal measure stratum is calculated through the content standardized value of each cationic element corresponding to the coal measure stratum in the well, and the inorganic component content of the coal measure stratum is calculated according to the mineralization coefficient and the mineral element content of the coal measure stratum;

[0014] Fifthly, regression analysis is performed on the inorganic component content of the coal measure stratum and the measured core ash content of the coal measure stratum, and an ash calculation model is established;

[0015] Sixthly, the ash content of the coal measure stratum of a new well in the same block is calculated through the ash calculation model, and the ash content of the coal measure stratum of the new well is obtained.

[0016] The following is a further optimization or / and improvement of the above-mentioned one of the technical solutions:

[0017] In the first step, the single-well normalization coefficient is calculated, specifically as follows:

[0018] Select standard well: select single well with complete stratigraphic position, good borehole condition, and complete logging data as standard well;

[0019] In the standard well and the correction well, respectively, select the pure mudstone section, pure conglomerate section or pure sandstone section near the target coal seam as the standard layer;

[0020] Statistically calculate the average content of each element in the standard layer of the standard well and the correction well, and the calculation formula of the average content of each element in the standard layer of the standard well and the correction well is the same, and the calculation formula of the average content of each element is as follows:

[0021]

[0022] Wherein, CE is an element; CE bav is the average content of the element in the standard layer, %; CE i is the i th content logging data of the element in the standard layer, %; n is the number of content logging data points of the element in the standard layer; and CE is any one of Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S and Cl elements;

[0023] The single-well normalization coefficient is calculated according to the following formula:

[0024]

[0025] In the formula, CE is an element; k m is the single-well normalization coefficient, dimensionless; (standard well) CE bav is the average content of the element in the standard layer of the standard well, %; (correction well) CE bav is the average content of the element in the standard layer of the correction well, %; and CE is any one of Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S and Cl elements;

[0026] The second step is specifically as follows:

[0027] The content normalization value of each element in the single well is calculated, and the content normalization value of the element is calculated as follows:

[0028] CE nor =k m ×CE l

[0029] In the formula, CE is an element; CE nor is the content normalization value of the element, %; k m is the single-well normalization coefficient, dimensionless; and CEl represents the elemental content logging data, in %; CE represents any one of the elements Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S, and Cl.

[0030] The third step above uses pure mudstone, pure conglomerate, or pure sandstone sections within the calibration well as characteristic strata. The mineral element content of these characteristic strata is calculated using the standardized values ​​of the corresponding elements, and then the mineralization coefficient is calculated based on the mineral element content of the characteristic strata. The details are as follows:

[0031] Among the standardized values ​​of element content corresponding to the characteristic layer, the standardized values ​​of cationic elements are selected to calculate the mineral element content of the characteristic layer. Cationic elements include Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn and Na. The mineral element content is the sum of the standardized values ​​of element content of each cationic element.

[0032] The mineralization coefficient is calculated using the following formula:

[0033] k2=1 / M1 矿物元素

[0034] In the formula, k2 is the mineralization coefficient, which is dimensionless; M1 矿物元素 The percentage represents the mineral element content of the characteristic layer.

[0035] The fourth step above involves calculating the mineral element content of the coal-bearing strata using the standardized values ​​of the content of each cationic element corresponding to the coal-bearing strata in the calibration well. Then, based on the mineralization coefficient and the mineral element content of the coal-bearing strata, the inorganic component content of the coal-bearing strata is calculated, as follows:

[0036] The inorganic component content of coal-bearing strata is calculated using the following formula:

[0037] M 无机 =M 矿物元素 ×k2

[0038] In the formula, M 无机 The inorganic component content of the coal-bearing strata is expressed as a percentage (%); k2 is the mineralization coefficient, dimensionless; M 矿物元素 The mineral element content of coal-bearing strata, %.

[0039] In the fifth step above, a linear regression analysis was performed on the inorganic component content of the coal-bearing strata and the measured core ash content of the coal-bearing strata to establish an ash content calculation model, which is as follows:

[0040] V ad =a×M 无机 +b

[0041] In the formula, M 无机 The inorganic component content of coal-bearing strata, %; V addenoted as , where is the measured core ash content of the coal-bearing strata, 'a' is the slope of the ash content calculation model, and 'b' is the intercept of the ash content calculation model.

[0042] In step six above, the ash content of the coal-bearing strata in the new well of the same block is calculated using the ash content calculation model, as detailed below:

[0043] When calculating the ash content of the coal-bearing strata in the new well, the mineral element content and inorganic component content of the coal-bearing strata in the new well are obtained first according to the second to fourth steps. The inorganic component content of the coal-bearing strata in the new well is then substituted into the ash content calculation model in the fifth step to obtain the ash content of the coal-bearing strata in the new well.

[0044] The second technical solution of the present invention is achieved through the following measures: a rapid evaluation device for coal seam ash content, comprising:

[0045] Standardized unit: Calculate the standardization coefficient for a single well;

[0046] The content of each element in a single well is standardized by using the single-well standardization coefficient to obtain the standardized content value of each element.

[0047] Mineralization coefficient calculation unit: Taking the pure mudstone section, pure conglomerate section or pure sandstone section in the calibration well as the characteristic layer, the mineral element content of the characteristic layer is calculated by the standardized value of the content of each cationic element corresponding to the characteristic layer, and then the mineralization coefficient is calculated by the mineral element content of the characteristic layer.

[0048] Inorganic component content calculation unit: Calculate the mineral element content of the coal-bearing strata using the standardized values ​​of the content of each cationic element corresponding to the coal-bearing strata in the calibration well, and calculate the inorganic component content of the coal-bearing strata based on the mineralization coefficient and the mineral element content of the coal-bearing strata;

[0049] Ash content calculation model unit: Regression analysis is performed on the inorganic component content of coal-bearing strata and the measured core ash content of the coal-bearing strata to establish an ash content calculation model;

[0050] New Well Ash Content Calculation Unit: The ash content of the coal-bearing strata in the new well of the same block is calculated using the ash content calculation model to obtain the ash content of the coal-bearing strata in the new well.

[0051] The following are further optimizations and / or improvements to the second technical solution of the above invention:

[0052] The aforementioned standardized units include:

[0053] Single-well standardized coefficient calculation unit: Used to calculate the single-well standardized coefficient, as detailed below:

[0054] Selection of standard wells: Select single wells with complete formations, good wellbore conditions, and complete logging data as standard wells;

[0055] In standard wells and calibration wells, strata with stable regional development near the target coal seam, such as pure mudstone, pure conglomerate, or pure sandstone, are selected as standard layers.

[0056] The average content of each element in the standard layers of both the standard wells and the calibration wells was calculated separately. The formula for calculating the average content of each element in the standard layers of both the standard wells and the calibration wells is the same. The formula for calculating the average content of each element is as follows:

[0057]

[0058] Where CE represents an element; CE bav The average content of elements in the standard layer, %; CE i represents the i-th content logging data of the standard layer element, in %; n represents the number of content logging data points of the standard layer element, in numbers; CE represents any one of the elements Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S, and Cl.

[0059] The standardization factor for a single well is calculated using the following formula:

[0060]

[0061] In the formula, CE represents an element; k m It is the single-well standardized coefficient, dimensionless; (standard well) CE bav The average elemental content (%) of the standard layer in the standard well; (calibration well) CE bav The average elemental content of the standard layer in the calibration well, expressed as a percentage (%); CE represents any one of the elements Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S, and Cl.

[0062] Standardization module: Calculates the standardized values ​​of each element in a single well; the standardized values ​​of the elemental content are calculated as follows:

[0063] CE nor =k m ×CE l

[0064] In the formula, CE represents an element; CE nor Standardized values ​​for element content, %; k m CE is the standardized coefficient for a single well, dimensionless. l represents the elemental content logging data, in %; CE represents any one of the elements Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S, and Cl.

[0065] The above-mentioned mineralization coefficient calculation unit includes:

[0066] Mineral element content calculation module for characteristic layers: Among the standardized values ​​of the elements corresponding to the characteristic layers, the standardized values ​​of the cationic elements are selected to calculate the mineral element content of the characteristic layers. The cationic elements include Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn and Na. The mineral element content is the sum of the standardized values ​​of the element content of each cationic element.

[0067] Mineralization coefficient calculation module: The mineralization coefficient is calculated using the following formula:

[0068] k2=1 / M1 矿物元素

[0069] In the formula, k2 is the mineralization coefficient, which is dimensionless; M1 矿物元素 The percentage represents the mineral element content of the characteristic layer.

[0070] The aforementioned inorganic component content calculation unit includes:

[0071] The mineral element content calculation module for coal-bearing strata: This module calculates the mineral element content of coal-bearing strata using the standardized values ​​of each cationic element corresponding to the coal-bearing strata in the calibration well. It then calculates the inorganic component content of the coal-bearing strata based on the mineralization coefficient and the mineral element content, as detailed below:

[0072] Inorganic component content calculation module: The inorganic component content of coal-bearing strata is calculated using the following formula:

[0073] M 无机 =M 矿物元素 ×k2

[0074] In the formula, M 无机 The inorganic component content of the coal-bearing strata is expressed as a percentage (%); k2 is the mineralization coefficient, dimensionless; M 矿物元素 The mineral element content of coal-bearing strata, %.

[0075] The above-mentioned ash content calculation model unit includes:

[0076] Linear Regression Analysis Module: Performs linear regression analysis on the inorganic component content of coal-bearing strata and the measured core ash content of the coal-bearing strata to establish an ash content calculation model.

[0077] Ash content calculation module: The ash content calculation model is as follows:

[0078] V ad =a×M 无机 +b

[0079] In the formula, M 无机 The inorganic component content of coal-bearing strata, %; V addenoted as , where is the measured core ash content of the coal-bearing strata, 'a' is the slope of the ash content calculation model, and 'b' is the intercept of the ash content calculation model.

[0080] The aforementioned new well ash content calculation unit includes:

[0081] The inorganic component content calculation module for Xinjing coal-bearing strata: When calculating the ash content of Xinjing coal-bearing strata, first calculate the mineral element content of Xinjing coal-bearing strata according to the mineral element content calculation module, and then calculate the inorganic component content according to the inorganic component content calculation module.

[0082] New Well Ash Content Calculation Module: Substitute the inorganic component content of the new well coal-bearing strata into the ash content calculation model of the ash content calculation module to obtain the ash content of the new well coal-bearing strata.

[0083] The cationic elements mentioned in the above steps refer to Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, and Na.

[0084] This invention utilizes drilling elemental logging data to rapidly calculate coal seam ash content, overcoming the shortcomings of experimental and logging methods, such as harsh construction conditions, high costs, and low timeliness. Through coal seam ash content calculation, it effectively guides the optimization and adjustment of horizontal well trajectories, further improving the drilling performance of horizontal coal seams. Simultaneously, it can be combined with other logging parameters to replace logging in the evaluation of coal seams exposed by horizontal well drilling, providing reliable geological information for subsequent reservoir stimulation schemes and offering an effective technical means for low-cost and high-efficiency horizontal well development of coalbed methane.

[0085] This invention has been applied to a coal seam in a certain block. It uses drilling elemental logging data to realize the rapid calculation of coal seam ash content. The calculated coal seam ash content is significantly consistent with the well logging GR, and the consistency rate with the measured core ash content is over 80%, which meets the coal quality assessment conditions. Real-time assessment of coal seam quality can be completed based on the calculated coal content. Attached Figure Description

[0086] Appendix Figure 1 This refers to the elemental logging data before standardization.

[0087] Appendix Figure 2 Standardized elemental logging data;

[0088] Appendix Figure 3 The mineral element content and inorganic component content of coal-bearing strata;

[0089] Appendix Figure 4 This is a trend chart of mineral element content and inorganic component content in coal-bearing strata;

[0090] Appendix Figure 5 Correlation analysis between inorganic component content in coal seams and measured ash content in core samples;

[0091] Appendix Figure 6 This is a graph showing the correlation between the inorganic component content of coal seams and the measured ash content in core samples.

[0092] Figure 5 In the middle, the left figure shows the calculated content of inorganic components in the coal seam and the measured ash content in the core sample, while the right figure is a regression analysis diagram. Detailed Implementation

[0093] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0094] In pure mudstone, pure conglomerate, and pure sandstone sections, there is almost no organic matter; the inorganic component content is approximately 100%, for example... Figure 1 In the middle, the dark gray fine conglomerate is a pure conglomerate.

[0095] The present invention will be further described below with reference to embodiments:

[0096] Example 1: A rapid evaluation method for coal seam ash content based on elemental logging while drilling, comprising:

[0097] The first step is to calculate the standardization factor for a single well;

[0098] Specifically as follows:

[0099] Selection of standard wells: Select single wells with complete formations, good wellbore conditions, and complete logging data as standard wells;

[0100] In standard wells and calibration wells, strata with stable regional development near the target coal seam, such as pure mudstone, pure conglomerate, or pure sandstone, are selected as standard layers.

[0101] The average content of each element in the standard layers of both the standard wells and the calibration wells was calculated separately. The formula for calculating the average content of each element in the standard layers of both the standard wells and the calibration wells is the same. The formula for calculating the average content of each element is as follows:

[0102]

[0103] Where CE represents an element; CE bav The average content of elements in the standard layer, %; CE i represents the i-th content logging data of the standard layer element, in %; n represents the number of content logging data points of the standard layer element, in numbers; CE represents any one of the elements Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S, and Cl.

[0104] The standardization factor for a single well is calculated using the following formula:

[0105]

[0106] In the formula, CE represents an element; k m It is the single-well standardized coefficient, dimensionless; (standard well) CE bav The average elemental content (%) of the standard layer in the standard well; (calibration well) CE bav CE represents the average elemental content of the standard layer in the calibration well, expressed as a percentage; CE is any one of the elements Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S, and Cl.

[0107] The following uses silicon (Si) as an example.

[0108]

[0109] In the formula, Si bav The average silicon content of the standard layer, in %; Si i is the i-th content logging data of silicon element in the standard layer, %; n is the number of content logging data points of Si element in the standard layer, in units.

[0110] The standardization factor for a single well (Si) is calculated using the following formula.

[0111]

[0112] In the formula, k1 is the standardization coefficient of Si for a single well, which is dimensionless; (standard well) Si bav The average Si content (%) in the standard layer of the standard well; (calibration well) Si bav This represents the average Si content of the standard layer in the calibration well.

[0113] The second step involves standardizing the logging data of each element in a single well using the single-well standardization coefficient to obtain the standardized values ​​of each element, as detailed below:

[0114] Calculate the standardized values ​​of each element in a single well; the standardized values ​​of the elemental contents are calculated as follows:

[0115] CE nor =k m ×CE l

[0116] In the formula, CE represents an element; CE nor Standardized values ​​for element content, %; k m CE is the standardized coefficient for a single well, dimensionless. l represents the elemental content logging data, in %; CE represents any one of the elements Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S, and Cl.

[0117] The following uses silicon (Si) as an example.

[0118] Si nor =k1×Si l

[0119] In the formula, Si nor is the standardized value of Si element content, %; k1 is the standardized coefficient of Si per well, dimensionless; Si l The data represents the Si element content (%) from the well logging data. Other elements can be calculated using the same method to obtain their corresponding standardized content values.

[0120] The third step involves using the pure mudstone, conglomerate, and sandstone sections deposited in an oxidizing environment as characteristic layers. Since these layers contain almost no organic matter, their inorganic content is approximately 100%. The mineral element content of each characteristic layer is calculated using the standardized values ​​of the corresponding cations, and then the mineralization coefficient is calculated based on this content. The details are as follows:

[0121] Among the standardized values ​​of element content corresponding to the characteristic layer, the standardized values ​​of cationic elements are selected to calculate the mineral element content of the characteristic layer. Cationic elements include Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn and Na. The mineral element content is the sum of the standardized values ​​of element content of each cationic element.

[0122] The mineralization coefficient is calculated using the following formula:

[0123] k2=1 / M1 矿物元素

[0124] In the formula, k2 is the mineralization coefficient, which is dimensionless; M1 矿物元素 The percentage represents the mineral element content of the characteristic layer.

[0125] Currently, elemental logging analyzes drill cuttings to obtain data on the content of 13 major rock-forming elements, including Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S, and Cl. However, it fails to effectively distinguish and identify the main components of coal seam organic matter, namely C, H, O, and N.

[0126] The formation consists of clay and silica-based minerals formed by the combination of cations such as Si, Al, Fe, Mg, K, Ca, and Ti with C, H, O, and N. Elemental logging data analysis shows a significant correlation between the content of formation mineral cations and the content of its inorganic components (minerals), which can be expressed as:

[0127] The mineral element content of the strata is calculated using the following formula:

[0128] M 矿物元素 =Si nor+Al nor +Fe nor +K nor +Mg nor +Ca nor +......

[0129] In the formula, Si nor The normalized values ​​for Si content, in %; Al nor Standardized values ​​for Al content, in %; Fe nor Standardized values ​​for Fe content, %; K nor The normalized value of K content, in %; Mg nor Here are the standardized values ​​for Mg content, in %; Ca... nor The value for the Ca content is a standardized value, expressed as a percentage.

[0130] Mineral element content M1 of the characteristic layer 矿物元素 Mineral element content M of coal-bearing strata 矿物元素 This calculation method can be used.

[0131] The fourth step involves calculating the mineral element content of the coal-bearing strata using the standardized values ​​of each cationic element corresponding to the coal-bearing strata within the calibration well. Based on the mineralization coefficient and the mineral element content of the coal-bearing strata, the inorganic component content is then calculated, as follows:

[0132] The inorganic component content of coal-bearing strata is calculated using the following formula:

[0133] M 无机 =M 矿物元素 ×k2

[0134] In the formula, M 无机 The inorganic component content of the coal-bearing strata is expressed as a percentage (%); k2 is the mineralization coefficient, dimensionless; M 矿物元素 The mineral element content of coal-bearing strata, %.

[0135] Coal ash is the residue remaining after complete combustion of coal, and it is one of the important indicators for evaluating coal quality. Coal ash almost entirely originates from the minerals in coal; however, during combustion, most of these minerals are oxidized, decomposed, and lose their water of crystallization. Therefore, the composition and content of coal ash are correlated with the composition and content of minerals in coal. Regression analysis can be used to determine a regression model (i.e., an ash calculation model) between ash and inorganic minerals.

[0136] The fifth step involves performing regression analysis on the inorganic component content of the coal-bearing strata and the measured core ash content of the coal-bearing strata to establish an ash content calculation model, as follows:

[0137] V ad =a×M 无机 +b

[0138] In the formula, M 无机 The inorganic component content of coal-bearing strata, %; V ad denoted as , where is the measured core ash content of the coal-bearing strata, 'a' is the slope of the ash content calculation model, and 'b' is the intercept of the ash content calculation model.

[0139] The sixth step involves using an ash content calculation model to calculate the ash content of the coal-bearing strata in the new well within the same block, as detailed below:

[0140] When calculating the ash content of the coal-bearing strata in the new well, the mineral element content and inorganic component content of the coal-bearing strata in the new well are obtained first according to the second to fourth steps. The inorganic component content of the coal-bearing strata in the new well is then substituted into the ash content calculation model in the fifth step to obtain the ash content of the coal-bearing strata in the new well.

[0141] Example 2: A rapid evaluation device for coal seam ash content, comprising:

[0142] Standardized unit: Calculate the standardization coefficient for a single well;

[0143] The content of each element in a single well is standardized by using the single-well standardization coefficient to obtain the standardized content value of each element.

[0144] Mineralization coefficient calculation unit: Taking the pure mudstone section, pure conglomerate section or pure sandstone section in the calibration well as the characteristic layer, the mineral element content of the characteristic layer is calculated by the standardized value of the content of each cationic element corresponding to the characteristic layer, and then the mineralization coefficient is calculated by the mineral element content of the characteristic layer.

[0145] Inorganic component content calculation unit: Calculate the mineral element content of the coal-bearing strata using the standardized values ​​of the content of each cationic element corresponding to the coal-bearing strata in the calibration well, and calculate the inorganic component content of the coal-bearing strata based on the mineralization coefficient and the mineral element content of the coal-bearing strata;

[0146] Ash content calculation model unit: Regression analysis is performed on the inorganic component content of coal-bearing strata and the measured core ash content of the coal-bearing strata to establish an ash content calculation model;

[0147] New Well Ash Content Calculation Unit: The ash content of the coal-bearing strata in the new well of the same block is calculated using the ash content calculation model to obtain the ash content of the coal-bearing strata in the new well.

[0148] Example 3: As an optimization of Example 2, the standardized unit specifically includes:

[0149] Single-well standardized coefficient calculation unit: Used to calculate the single-well standardized coefficient, as detailed below:

[0150] Selection of standard wells: Select single wells with complete formations, good wellbore conditions, and complete logging data as standard wells;

[0151] In standard wells and calibration wells, strata with stable regional development near the target coal seam, such as pure mudstone, pure conglomerate, or pure sandstone, are selected as standard layers.

[0152] The average content of each element in the standard layers of both the standard wells and the calibration wells was calculated separately. The formula for calculating the average content of each element in the standard layers of both the standard wells and the calibration wells is the same. The formula for calculating the average content of each element is as follows:

[0153]

[0154] Where CE represents an element; CE bav The average content of elements in the standard layer, %; CE i represents the i-th content logging data of the standard layer element, in %; n represents the number of content logging data points of the standard layer element, in numbers; CE represents any one of the elements Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S, and Cl.

[0155] The standardization factor for a single well is calculated using the following formula:

[0156]

[0157] In the formula, CE represents an element; k m It is the single-well standardized coefficient, dimensionless; (standard well) CE bav The average elemental content (%) of the standard layer in the standard well; (calibration well) CE bav The average elemental content of the standard layer in the calibration well, expressed as a percentage (%); CE represents any one of the elements Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S, and Cl.

[0158] Standardization module: Calculates the standardized values ​​of each element in a single well; the standardized values ​​of the elemental content are calculated as follows:

[0159] CE nor =k m ×CE l

[0160] In the formula, CE represents an element; CE nor Standardized values ​​for element content, %; k m CE is the standardized coefficient for a single well, dimensionless. l represents the elemental content logging data, in %; CE represents any one of the elements Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S, and Cl.

[0161] Example 4: As an optimization of Example 2, the mineralization coefficient calculation unit includes:

[0162] Mineral element content calculation module for characteristic layers: Among the standardized values ​​of element content corresponding to the characteristic layers, the standardized values ​​of cationic elements are selected to calculate the mineral element content of the characteristic layers. Cationic elements include Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn and Na. The mineral element content is the sum of the standardized values ​​of element content of each cationic element.

[0163] Mineralization coefficient calculation module: The mineralization coefficient is calculated using the following formula:

[0164] k2=1 / M1 矿物元素

[0165] In the formula, k2 is the mineralization coefficient, which is dimensionless; M1 矿物元素 The percentage represents the mineral element content of the characteristic layer.

[0166] Example 5: As an optimization of Example 2, the inorganic component content calculation unit includes:

[0167] The mineral element content calculation module for coal-bearing strata: This module calculates the mineral element content of coal-bearing strata using the standardized values ​​of each cationic element corresponding to the coal-bearing strata in the calibration well. It then calculates the inorganic component content of the coal-bearing strata based on the mineralization coefficient and the mineral element content, as detailed below:

[0168] Inorganic component content calculation module: The inorganic component content of coal-bearing strata is calculated using the following formula:

[0169] M 无机 =M 矿物元素 ×k2

[0170] In the formula, M 无机 The inorganic component content of the coal-bearing strata is expressed as a percentage (%); k2 is the mineralization coefficient, dimensionless; M 矿物元素 The mineral element content of coal-bearing strata, %.

[0171] Example 6: As an optimization of Example 2, the ash content calculation model unit includes:

[0172] Linear Regression Analysis Module: Performs linear regression analysis on the inorganic component content of coal-bearing strata and the measured core ash content of the coal-bearing strata to establish an ash content calculation model.

[0173] Ash content calculation module: The ash content calculation model is as follows:

[0174] V ad =a×M 无机 +b

[0175] In the formula, M 无机The inorganic component content of coal-bearing strata, %; V ad denoted as , where is the measured core ash content of the coal-bearing strata, 'a' is the slope of the ash content calculation model, and 'b' is the intercept of the ash content calculation model.

[0176] Example 7: As an optimization of Example 2, the ash content calculation unit for Niijui includes:

[0177] The inorganic component content calculation module for Xinjing coal-bearing strata: When calculating the ash content of Xinjing coal-bearing strata, first calculate the mineral element content of Xinjing coal-bearing strata according to the mineral element content calculation module, and then calculate the inorganic component content according to the inorganic component content calculation module.

[0178] New Well Ash Content Calculation Module: Substitute the inorganic component content of the new well coal-bearing strata into the ash content calculation model of the ash content calculation module to obtain the ash content of the new well coal-bearing strata.

[0179] Implementation Case:

[0180] The rapid evaluation method for coal seam ash content based on elemental logging while drilling described in Embodiment 1 of this invention is applied to the calculation of coal seam ash content in a coalbed methane block:

[0181] The first step is to calculate the standardization factor for a single well;

[0182] The second step is to calculate the standardized values ​​of each element in a single well, and the data before and after standardization (see...). Figure 1 , 2 );

[0183] The third step is to calculate the mineralization coefficient based on the mineral element content of the characteristic layers (see...). Figure 3 Taking the well section with a depth of 3117.5 meters and a lithology of dark gray fine conglomerate as the characteristic section, the mineralization coefficient of the characteristic section was calculated as: k2 = 1 / 51.27% = 1.96.

[0184] The fourth step is to calculate the inorganic component content of each coal-bearing stratum using the following formulas, as well as the mineral element content and inorganic component content of each coal-bearing stratum in a single well (see...). Figure 3 , 4 ),

[0185] M 无机 =M 矿物元素 ×1.96

[0186] The fifth step involves performing linear regression analysis using the calculated inorganic component content of the coal-bearing strata (lithology: black coal) and the measured core ash content. The details are as follows:

[0187] Using the calculated inorganic component content of the coal-bearing strata as the x-value and the measured core ash content as the y-value, a scatter plot was created using Excel. Selecting the data in the scatter plot, right-clicking, and choosing "Add Trendline" were all done. In the "Trendline Options" displayed on the right side of the Excel interface, "Linear" was selected. Simultaneously, in the "Trend Prediction Options," "Display Formula" and "Display R-squared Value" were selected to obtain the ash content calculation model (see...). Figure 5 ):

[0188] V ad =0.6972×M 无机 +8.63

[0189] Step 6: First, obtain the mineral element content and inorganic component content of the coal-bearing strata in the new well according to steps 2 to 4. Then, substitute the inorganic component content of the new well's coal-bearing strata into the ash content calculation model in step 5 to complete the ash content calculation of the new well's coal seam (see...). Figure 6 ).

[0190] The above technical features constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A coal seam ash quick evaluation method based on a while-drilling element logging, characterized in that, The method comprises the following steps: First, calculating the single-well normalization coefficient; Second, using the single-well normalization coefficient to standardize the content of each element in the logging data of the single well to obtain the content standardization value of each element; Third, taking the pure mudstone section, the pure conglomerate section or the pure sandstone section in the calibration well as the characteristic section, calculating the mineral element content of the characteristic section through the content standardization value of each cationic element corresponding to the characteristic section, and then calculating the mineralization coefficient through the mineral element content of the characteristic section; Fourth, calculating the mineral element content of the coal measure stratum in the calibration well through the content standardization value of each cationic element corresponding to the coal measure stratum, and calculating the inorganic component content of the coal measure stratum according to the mineralization coefficient and the mineral element content of the coal measure stratum; Fifth, performing regression analysis on the inorganic component content of the coal measure stratum and the measured core ash content of the coal measure stratum to establish an ash content calculation model; Sixth, calculating the ash content of the coal measure stratum in a new well in the same block by using the ash content calculation model to obtain the ash content of the coal measure stratum in the new well.

2. The coal seam ash content rapid evaluation method based on the while-drilling element logging according to claim 1, characterized in that, In the first step, the single-well normalization coefficient is calculated as follows: Selecting a standard well: selecting a single well with complete stratum position, good wellbore condition and complete logging data as the standard well; Selecting a standard layer in the standard well and the calibration well: selecting a pure mudstone section, a pure conglomerate section or a pure sandstone section near the target coal seam and developed stably in the region as the standard layer; Statistically calculating the average content of each element in the standard layer of the standard well and the calibration well: the average content of each element in the standard layer of the standard well and the calibration well is calculated by the same formula, and the formula for calculating the average content of each element is as follows: Wherein, CE is an element; CE bav is the content average value of the standard layer element, %; CE i is the i th content logging data of the standard layer element, %; n is the content logging data point number of the element of the standard layer, pieces; CE is any one of Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S, and Cl elements; The single-well normalization coefficient is calculated by the following formula, wherein CE is an element; k m is a single-well normalization coefficient, dimensionless; (standard well) CE bav is an average value of the content of the element of the standard layer of the standard well, %; (correction well) CE bav is an average value of the content of the element of the standard layer of the correction well, %; CE is any one of Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S, and Cl elements; Or / and, the second step is as follows: Calculating the content standardization value of each element in the single well: the content standardization value of each element is calculated as follows: CE nor = k m x CE l In the formula, CE is an element; CE nor is a content normalized value of the element, %; k m is a single well normalized coefficient, dimensionless; CE l is content logging data of the element, %; CE is any one of Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S, and Cl elements.

3. The coal seam ash content rapid evaluation method based on the while-drilling element logging according to claim 1 or 2, characterized in that, In the third step, taking the pure mudstone section, the pure conglomerate section or the pure sandstone section in the calibration well as the characteristic section, calculating the mineral element content of the characteristic section through the content standardization value of each cationic element corresponding to the characteristic section, and then calculating the mineralization coefficient through the mineral element content of the characteristic section, which is specifically as follows: In the content standardization value of the element corresponding to the characteristic section, the content standardization value of the cationic element is selected to calculate the mineral element content of the characteristic section, the cationic element includes Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn and Na, and the mineral element content is the sum of the content standardization values of each cationic element; The mineralization coefficient is calculated by the following formula: k2 = 1 / M1 矿物元素 In the formula, k2 is the mineralization coefficient, which is dimensionless; M1 矿物元素 M1 is the content of the mineral element characteristic of the section, in %. Or / and, in the fourth step, the mineral element content of the coal measure stratum in the calibration well is calculated through the content standardization value of each cationic element corresponding to the coal measure stratum, and the inorganic component content of the coal measure stratum is calculated according to the mineralization coefficient and the mineral element content of the coal measure stratum, which is specifically as follows: The inorganic component content of the coal measure stratum is calculated by the following formula: M 无机 = M 矿物元素 x k2 wherein M 无机 is the inorganic component content of the coal measure strata, %; k2 is the mineralization coefficient, dimensionless; M 矿物元素 is the mineral element content of the coal measure strata, %.

4. The coal seam ash content rapid evaluation method based on the while-drilling element logging according to claim 3, characterized in that In the fifth step, linear regression analysis is performed on the inorganic component content of the coal measure stratum and the measured core ash content of the coal measure stratum to establish an ash content calculation model, and the ash content calculation model is as follows: V ad = a x M 无机 + b where M 无机 is the inorganic component content of the coal measure strata, %; V ad is the measured core ash content of the coal measure strata, a is the slope of the ash calculation model, and b is the intercept of the ash calculation model.

5. The coal seam ash content rapid evaluation method based on the element logging while drilling according to claim 4, characterized in that, In the sixth step, the ash content of the coal measure strata of the new well in the same block is calculated by using the ash content calculation model, and the ash content of the coal measure strata of the new well is obtained, which is specifically as follows: In the calculation of the ash content of the coal measure strata of the new well, the mineral element content and the inorganic component content of the coal measure strata of the new well are obtained according to the second step to the fourth step, and the inorganic component content of the coal measure strata of the new well is substituted into the ash content calculation model of the fifth step to obtain the ash content of the coal measure strata of the new well.

6. A coal seam ash quick evaluation device, characterized by, It comprises: A standardization unit for calculating a single-well standardization coefficient; The content of each element of the single well is standardized and processed to obtain the content standardization value of each element after the content of each element of the single well is recorded and standardized; A mineralization coefficient calculation unit: taking the pure mudstone section, the pure gravel section or the pure sandstone section in the calibration well as a characteristic section, the mineral element content of the characteristic section is calculated through the content standardization value of each cationic element corresponding to the characteristic section, and then the mineralization coefficient is calculated through the mineral element content of the characteristic section; An inorganic component content calculation unit: the mineral element content of the coal measure strata is calculated by using the content standardization value of each cationic element corresponding to the coal measure strata in the calibration well, and the inorganic component content of the coal measure strata is calculated according to the mineralization coefficient and the mineral element content of the coal measure strata; An ash content calculation model unit: regression analysis is performed on the inorganic component content of the coal measure strata and the measured core ash content of the coal measure strata to establish an ash content calculation model; A new well ash content calculation unit: the ash content of the coal measure strata of the new well in the same block is calculated by using the ash content calculation model, and the ash content of the coal measure strata of the new well is obtained.

7. The coal seam ash rapid evaluation device according to claim 6, characterized by The standardization unit comprises: A single-well standardization coefficient calculation unit for calculating a single-well standardization coefficient, which is specifically as follows: Selecting a standard well: selecting a single well with complete stratum position, good wellbore condition and complete logging data as a standard well; In the standard well and the calibration well, a pure mudstone section, a pure gravel section or a pure sandstone section near the target coal seam is selected as a standard layer; The average content of each element of the standard layer of the standard well and the calibration well is calculated, and the average content of each element of the standard layer of the standard well and the calibration well is calculated by the same formula, and the average content of each element is calculated by the following formula: Wherein, CE is an element; CE bav is the content average value of the standard layer element, %; CE i is the i th content logging data of the standard layer element, %; n is the content logging data point number of the element of the standard layer, pieces; CE is any one of Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S, and Cl elements; The single-well standardization coefficient is calculated by the following formula, wherein CE is an element; k m is a single well normalization coefficient, dimensionless; (standard well) CE bav is an average value of the content of the element of the standard layer of the standard well, %; (corrected well) CE bav is an average value of the content of the element of the standard layer of the corrected well, %; CE is any one of Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S, Cl elements; The standardization module: the content standardization value of each element of the single well is calculated, and the content standardization value of each element is calculated as follows: CE nor = k m x CE l In the formula, CE is an element; CE nor is a content normalized value of the element, %; k m is a single well normalized coefficient, dimensionless; CE l is content logging data of the element, %; CE is any one of Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn, Na, P, S, and Cl elements.

8. The coal seam ash rapid evaluation device according to claim 6 or 7, characterized by, The mineralization coefficient calculation unit comprises: A mineral element content calculation module of the characteristic layer section: the content standardization value of the cationic element is selected from the content standardization value of the characteristic layer section corresponding element to calculate the mineral element content of the characteristic layer section, and the cationic element comprises Si, Al, Fe, Mg, K, Ca, Ti, Ba, Mn and Na, and the mineral element content is the sum of the element content standardization values of each cationic element; A mineralization coefficient calculation module: the mineralization coefficient is calculated by the following formula: k2 = 1 / M1 矿物元素 where k2 is the mineralization coefficient, dimensionless; M1 矿物元素 is the mineral element content of the characteristic interval, %; Or / and, the inorganic component content calculation unit comprises: The mineral element content calculation module of the coal measure stratum: the mineral element content of the coal measure stratum is calculated by using the normalized value of the content of each cation element corresponding to the coal measure stratum in the calibration well, the inorganic component content of the coal measure stratum is calculated according to the mineralization coefficient and the mineral element content of the coal measure stratum, and the specific calculation is as follows: The inorganic component content calculation module: the inorganic component content of the coal measure stratum is calculated according to the following formula: M 无机 = M 矿物元素 x k2 wherein M 无机 is the inorganic component content of the coal measure strata, %; k2 is the mineralization coefficient, dimensionless; M 矿物元素 is the mineral element content of the coal measure strata, %.

9. The rapid coal seam ash evaluation device according to any one of claims 6 to 8, characterized in that The ash content calculation model unit includes: The linear regression analysis module: the linear regression analysis is performed on the inorganic component content of the coal measure stratum and the measured core ash content of the coal measure stratum, the ash content calculation model is established, The ash content calculation module: the ash content calculation model is as follows: V ad = a x M 无机 + b where M 无机 is the inorganic component content of the coal measure strata, %; V ad is the measured core ash content of the coal measure strata, a is the slope of the ash calculation model, and b is the intercept of the ash calculation model.

10. The coal seam ash rapid evaluation device according to claim 9, characterized by, The new well ash content calculation unit includes: The inorganic component content calculation module of the coal measure stratum of the new well: when the ash content of the coal measure stratum of the new well is calculated, the mineral element content of the coal measure stratum of the new well is calculated according to the mineral element content calculation module of the coal measure stratum, and the inorganic component content is calculated according to the inorganic component content calculation module, The new well ash content calculation module: the inorganic component content of the coal measure stratum of the new well is substituted into the ash content calculation model of the ash content calculation module to obtain the ash content of the coal measure stratum of the new well.

Images