Reservoir evaluation method based on aftereffect release gas quantity

Abstract

The invention discloses a reservoir evaluation method based on an aftereffect release gas amount, and relates to the technical field of geological evaluation while drilling, the aftereffect gas amount and the aftereffect gas efficiency are calculated through standardized processing of aftereffect section gas logging total hydrocarbon on the basis of logging time data, and the aftereffect release gas amount and the aftereffect gas efficiency are calculated according to the change characteristics of aftereffect intensity along with the reservoir opening time. A Gaussian function mode is adopted to fit and establish an aftereffect gas efficiency function, the total amount of aftereffect released gas is obtained through integration, and after the density of drilling fluid is standardized, the corresponding aftereffect released gas amount of a tested oil well test section is fitted with the open-flow capacity of the test section to obtain a correlation function of the aftereffect released gas amount and the open-flow capacity; the reservoir evaluation standard of the aftereffect release gas amount is correspondingly established by combining the reservoir evaluation standard of the open-flow capacity, the reservoir evaluation method is formed, and the problems that in the prior art, a gas logging parameter correction technology dominated by engineering parameters such as drilling time, displacement and drill bit size is obviously not applicable, and the reservoir responsiveness of gas logging parameters is difficult to improve are solved.

Description

Technical Field

[0001] The invention relates to the technical field of geological evaluation while drilling, and in particular to a reservoir evaluation method based on after-effect released gas volume. Background Art

[0002] At present, reservoir evaluation while drilling is mainly based on logging parameters such as gas logging and drilling time that have a certain responsiveness to the reservoir, combined with the influence of engineering parameters such as drilling pressure, rotation speed, displacement, etc. on these response parameters for correction. Evaluation is carried out according to changes in curve morphology or using reservoir evaluation technology based on these parameters. It is widely used with good results.

[0003] However, with the widespread application of new drilling technologies such as fine pressure control, liquid-gas separators, and oil-based drilling fluids in recent years, the key parameters of reservoir evaluation while drilling - gas logging parameters - have been seriously affected. The gas logging parameter values ​​are significantly lower than those of old wells that do not use these new drilling technologies, and are completely mismatched with the test production, resulting in a significant deterioration in the application effect of existing reservoir evaluation while drilling methods, especially methods based on gas logging parameter values. Moreover, due to changes in process characteristics and procedures, the existing gas logging parameter correction technology dominated by engineering parameters such as drilling time, displacement, and drill bit size is obviously not applicable, and it is difficult to improve the reservoir responsiveness of gas logging parameters.

[0004] The "failure" of gas logging parameters makes it difficult to find parameters with good reservoir responsiveness in existing logging parameters, which is undoubtedly a huge obstacle to the development of reservoir evaluation while drilling technology. Therefore, it is necessary to innovate in logging response parameters and study new reservoir evaluation while drilling methods. Summary of the invention

[0005] The purpose of the present invention is to solve the above problems and propose a reservoir evaluation method based on the after-effect released gas volume. The method is based on the logging time data and is a new reservoir evaluation method while drilling.

[0006] The present invention is achieved through the following technical solutions:

[0007] The reservoir evaluation method based on the after-effect gas release volume includes the following steps:

[0008] a. Collect the logging data, well logging data and oil testing information of specific layers of the tested wells in the study area, and select the corresponding aftereffects of the gas testing display in the test section;

[0009] b. extracting the corresponding total hydrocarbon data from the screened aftereffects according to the aftereffect time;

[0010] c. Standardize the extracted after-effect full hydrocarbon data in terms of base value, time interval and displacement;

[0011] d. Based on the time from the onset to the end of the aftereffect, the standard total hydrocarbons are accumulated to obtain the aftereffect gas volume, and then the aftereffect gas efficiency is calculated in combination with the static time;

[0012] e. Integrate the after-effect gas efficiency of multiple after-effects corresponding to the same gas test display, and fit the time difference between the occurrence time of the gas test display and the occurrence time of the after-effect to establish the after-effect gas efficiency function, and obtain the total amount of after-effect released gas displayed by the gas test;

[0013] f. The open-flow rate of the tested section of the specific stratum of the tested oil wells in the study area and the total amount of after-effect released gas corresponding to the gas test display in the test section are analyzed with the standardization of the drilling fluid density to obtain the correlation function of the total amount of after-effect released gas and the open-flow rate;

[0014] g. Based on the reservoir evaluation standard of open flow rate, the corresponding reservoir evaluation standard of the total amount of after-effect released gas is formed to form an evaluation method for reservoir evaluation of new wells.

[0015] Furthermore, in step c, the total hydrocarbon TG is standardized in terms of base value, time interval and displacement according to the following formula (I):

[0016] TG 标准 =(TG-TG 基值 )×t 间隔 ×V / V 标准 Formula (I),

[0017] In formula (I), TG 标准 is the standard total hydrocarbon; TG is the measured total hydrocarbon; TG 基值 is the total hydrocarbon value; t 间隔 is the time interval; V is the measured displacement; V 标准 For standard displacement.

[0018] Furthermore, in step c, the selection of the total hydrocarbon base value is mainly based on the change characteristics of the total hydrocarbon curve, and is implemented according to the after-effect description specification; the time interval is based on the actual sampling interval of the logging time data, and the time interval is 0.5 to 2 minutes; the selection of the standard displacement is mainly based on the average value of the parameters commonly used in drilling in the study area, and the standard displacement is 10 to 30L / s.

[0019] Further, in step d, the after-effect gas volume M 后效 、After-effect gas efficiency η 后效 Calculated according to the following formula (II) and (III):

[0020] M 后效 =∑TG 标准 (Ⅱ);

[0021] η 后效 = M 后效 / t 静止 (III);

[0022] In formula (II) and (III), M 后效 is the after-effect gas volume, η 后效 is the after-effect gas efficiency, t 静止 For still time.

[0023] Furthermore, in step e, the post-gas efficiency function is fitted and established as the following formula (IV):

[0024]

[0025] In formula (IV), Δt is the time difference from the occurrence time of gas measurement display to the occurrence time of aftereffect; a, b, c are fitting parameters.

[0026] Furthermore, in step e, the function integral of the total amount of after-effect released gas is accumulated with the time difference as the axis and restored to the initial value as the cutoff, that is, the accumulation ends when the after-effect gas efficiency decreases to the initial value of the function when the time difference is zero. When f(cutoff value)=f(0), the total amount of after-effect released gas satisfies the following formula (V):

[0027]

[0028] Where M 后效释放 It is the total amount of gas released in the aftereffect.

[0029] Furthermore, in step e, if there are multiple gas test displays in the test section that all have corresponding after-effects, the total amount of after-effect released gas displayed by the multiple gas test displays is accumulated.

[0030] Furthermore, in step f, the correlation function between the total amount of after-effect released gas and the open flow rate is:

[0031] Unimpeded flow rate = F(ΣM 后效释放 ×ρ / ρ标标准 ) (VI);

[0032] Where, ρ is the measured drilling fluid density; ρ 标准 is the standard drilling fluid density.

[0033] Furthermore, the standard drilling fluid density was selected based on the average value of the parameters commonly used for drilling in the study area.

[0034] Furthermore, in step g, there are two reservoir evaluation criteria for unobstructed flow, one is the upper limit of the dry layer, and the other is the lower limit of the industrial gas flow.

[0035] When the unobstructed flow rate is ≤ the upper limit of the dry layer, it is a dry layer;

[0036] When the upper limit of the dry layer < unobstructed flow ≤ lower limit of industrial air flow, it is a poor air layer;

[0037] When the unobstructed flow rate is greater than the lower limit of industrial air flow, it is an air layer.

[0038] Furthermore, according to the functional relationship between the total amount of after-effect released gas and the open flow rate, combined with the reservoir evaluation standard of the open flow rate, the reservoir evaluation standard of the total amount of after-effect released gas is established. According to the reservoir evaluation standard of the total amount of after-effect released gas, the reservoir evaluation of the new well is carried out:

[0039] First, determine the reservoir location based on the gas logging display, and then calculate the total amount of after-effect released gas in the new well reservoir through steps b to e, and combine it with the evaluation criteria to obtain the evaluation result.

[0040] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0041] 1. In the present invention, based on the logging time data, the after-effect gas volume and after-effect gas efficiency of the after-effect are calculated by standardizing the total hydrocarbon of the after-effect section gas test. According to the variation characteristics of the after-effect intensity with the reservoir opening time, the Gaussian function mode is used to fit and establish the after-effect gas efficiency function, and the total amount of after-effect released gas is obtained by integration. The total amount of after-effect released gas corresponding to the test section of the tested oil well is normalized with the open flow rate of the test section to obtain the correlation function of the two, and the reservoir evaluation standard of the open flow rate is combined with the reservoir evaluation standard to establish the reservoir evaluation standard of the after-effect released gas volume, so as to form a reservoir evaluation method, which is reliable.

[0042] 2. In the present invention, the aftereffect is innovatively introduced into the reservoir while drilling evaluation system. The prior art uses the aftereffect as an engineering evaluation parameter to evaluate whether the drilling fluid density is reasonable, whether the formation pressure prediction is accurate, whether the circulation time after pump stop is sufficient, and other issues related to drilling safety, and basically does not involve reservoir while drilling evaluation. In the present invention, the aftereffect is innovatively introduced into the reservoir while drilling evaluation system, and the aftereffect gas volume is used as a breakthrough. A new parameter, the total amount of aftereffect released gas, is obtained through standardized processing, function fitting, and integration. It objectively reflects the ability of the reservoir to continuously release natural gas into the wellbore after it is opened, breaking the limitation that no parameters in the aftereffect parameters can be used for reservoir while drilling evaluation, and expanding the parameter basis for reservoir while drilling evaluation.

[0043] 3. In the present invention, the Gaussian function pattern fitting is innovatively adopted to establish the after-effect gas efficiency function. The prior art has not disclosed a method for obtaining the total amount of after-effect gas released by fitting the after-effect gas efficiency function. In the present invention, the Gaussian function pattern fitting is adopted to establish the after-effect gas efficiency function in view of the unique variation characteristics of the after-effect strength with the reservoir opening time, and the function fitting of the unconventional curve of the after-effect gas efficiency is realized, which truly reflects the variation characteristics of the after-effect strength. The total amount of after-effect gas released obtained by integration is also more accurate and reliable, avoiding the result difference caused by the inapplicability of the function, and the method is more applicable. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is the after-effect gas efficiency function fitting and cut-off value determination.

[0045] Figure 2 It is the correlation function of the total amount of after-effect released gas and the open flow rate and the reservoir evaluation standard. DETAILED DESCRIPTION

[0046] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0047] Example 1

[0048] To facilitate the public to understand this solution, this embodiment takes the P well area as an example to further illustrate this solution, which involves the technical field of geological evaluation while drilling, and specifically includes the following steps:

[0049] first step:

[0050] The logging data, well logging data and oil testing information of the D layer system of the tested wells in the P well area are collected to screen out the aftereffects corresponding to the gas testing display in the test section.

[0051] Step 2:

[0052] For the screened after-effects, the corresponding total hydrocarbon data are extracted according to the after-effect time.

[0053] Step 3:

[0054] The extracted after-effect full hydrocarbon data are standardized in terms of base value, time interval and displacement.

[0055] Since the logging time data is used, the base value, time interval and displacement have a great influence on the calculation of the after-effect gas volume, and must be standardized. In this step, the base value, time interval and displacement of the total hydrocarbon TG are standardized according to the following formula (I):

[0056] TG 标准 =(TG-TG 基值 )×t 间隔 ×V / V 标准 Formula (I),

[0057] In formula (I), TG 标准 is the standard total hydrocarbon (%); TG is the measured total hydrocarbon (%); TG 基值 is the total hydrocarbon value (%); t 间隔 is the time interval (min); V is the measured displacement (L / s); V 标准 is the standard displacement (L / s).

[0058] In this step, the selection of the total hydrocarbon base value is mainly based on the change characteristics of the total hydrocarbon curve and is implemented according to the after-effect description specification; the time interval is based on the actual sampling interval of the logging time data. Generally, the time interval is 0.5 to 2 minutes; the selection of the standard displacement is mainly based on the average value of the parameters commonly used in drilling in the study area. Generally, the standard displacement is 10 to 30 L / s.

[0059] In this implementation, the standard displacement is taken as 15L / s.

[0060] Step 4:

[0061] Based on the time from the occurrence to the end of the after-effect, the standard total hydrocarbons are accumulated to obtain the after-effect gas volume, and then the after-effect gas efficiency is calculated in combination with the static time.

[0062] In this step, the after-effect gas volume M 后效 、After-effect gas efficiency η 后效 Calculated according to the following formula (II) and (III):

[0063] M 后效 =∑TG 标准 (Ⅱ);

[0064] η 后效 = M 后效 / t 静止 (III);

[0065] In formula (II) and (III), M 后效 is the after-effect gas volume (%), η 后效 is the after-effect gas efficiency (% / h), t 静止 is the stationary time (h).

[0066] In this embodiment, taking the P1 well in the P well area as an example, there is 1 gas test display in the test section, corresponding to 4 after-effects, and the after-effect total hydrocarbon measurement is based on the proportion of hydrocarbon gas content in the drilling fluid, the unit is %, and the calculated after-effect gas efficiency is 4.5% / h, 16.8% / h, 27.3% / h, and 12.0% / h, respectively, refer to Table 1.

[0067] Table 1: P1 Well After-Effect Gas Efficiency Calculation Parameters Statistics

[0068]

[0069] Step 5:

[0070] Integrate the after-effect gas efficiency of multiple after-effects corresponding to the same gas test display, and use the Gaussian function mode to fit the time difference from the occurrence time of the gas test display to the occurrence time of the after-effect to establish the after-effect gas efficiency function, and calculate the total amount of after-effect released gas of the gas test display by function integration. If there are multiple gas test displays with corresponding after-effects in the test section, the total amount of after-effect released gas of multiple gas test displays will be accumulated.

[0071] In this scheme, depending on the different areas to be studied, the function fitted by the collected data can include multiple types of functions, that is, the function type can be adjusted according to the actual conditions of different areas, and the adjustment is based on the data change characteristics and the function has the greatest consistency rate.

[0072] Judging from the characteristics of the gas wells studied recently, as the reservoir opening time increases, the aftereffect intensity will increase rapidly from zero and then gradually decrease to zero. This is inconsistent with the conventional exponential, logarithmic, high-order and other function characteristics. Therefore, a Gaussian function model that is more in line with this change characteristic is used for fitting.

[0073] In this scheme, the efficiency function after fitting is established as the following formula (IV):

[0074]

[0075] In formula (IV), Δt is the time difference from the occurrence time of gas measurement display to the occurrence time of aftereffect; a, b, c are fitting parameters.

[0076] In this embodiment, the after-effect gas efficiency of the four after-effects corresponding to the gas measurement display is integrated, referring to Figure 1 The time difference between the occurrence time of the gas test and the occurrence time of the aftereffect is fitted using the Gaussian function model to establish the aftereffect gas efficiency function as follows:

[0077]

[0078] The function integral of the total amount of after-effect released gas is accumulated with the time difference as the axis and restored to the initial value as the cutoff, that is, the accumulation ends when the after-effect gas efficiency decreases to the initial value of the function when the time difference is zero. When f(cutoff value)=f(0), the total amount of after-effect released gas satisfies the following formula (V):

[0079]

[0080] Where M 后效释放 It is the total amount of gas released in the aftereffect.

[0081] In this embodiment, according to the initial value of the after-effect gas efficiency function f(0)=0.03, the cutoff value is determined to be 155, that is, f(155)=f(0), and the total amount of after-effect released gas displayed by the gas test is cumulatively calculated to be 1507.5, which is the total amount of after-effect released gas in the test section.

[0082]

[0083] Step 6:

[0084] The open flow rate tested in the test section of a specific layer of the tested oil wells in the study area and the total amount of after-effect released gas corresponding to the gas testing display in the test section were subjected to correlation analysis combined with the standardization of the drilling fluid density to obtain the correlation function between the total amount of after-effect released gas and the open flow rate.

[0085] In this step, the correlation function between the total amount of after-effect released gas and the open flow rate is:

[0086] Unimpeded flow = F(∑M 后效释放 ×ρ / ρ 标准 ) (VI);

[0087] Where, ρ is the measured drilling fluid density; ρ 标准 is the standard drilling fluid density.

[0088] Due to differences in geological conditions, the relationship between the open flow rate and the total amount of after-effect released gas in different layers in different regions is different, so the type of function F is variable, generally a linear function, but also an exponential function, logarithmic function, high-order function, etc. The selection of standard drilling fluid density is mainly based on the average value of parameters commonly used in drilling in the study area.

[0089] In this embodiment, the open-flow rate of the D layer test section of the tested oil well in the study area and the total amount of after-effect released gas corresponding to the gas test display in the test section are analyzed by combining the standardization of the drilling fluid density to obtain the correlation function of the total amount of after-effect released gas and the open-flow rate. Figure 2 The standard drilling fluid density is 1.35g / cm 3 .

[0090] Unimpeded flow = F(M 后效释放 ×ρ / ρ 标准 )=194.7×M 后效释放 -16877.

[0091] Step 7:

[0092] According to the reservoir evaluation standard of open flow rate, the corresponding reservoir evaluation standard of total amount of after-effect released gas is formed, and an evaluation method is formed for reservoir evaluation of new wells.

[0093] In this step, there are two reservoir evaluation criteria for unobstructed flow, one is the upper limit of dry layer, and the other is the lower limit of industrial gas flow.

[0094] When the unobstructed flow rate is ≤ the upper limit of the dry layer, it is a dry layer;

[0095] When the upper limit of the dry layer < unobstructed flow ≤ lower limit of industrial air flow, it is a poor air layer;

[0096] When the unobstructed flow rate is greater than the lower limit of industrial air flow, it is an air layer.

[0097] According to the functional relationship between the total amount of after-effect released gas and the open flow rate, combined with the reservoir evaluation standard of the open flow rate, the reservoir evaluation standard of the total amount of after-effect released gas is established.

[0098] According to the reservoir evaluation standard of the total amount of after-effect released gas, reservoir evaluation can be carried out on new wells, that is, first determine the reservoir location according to the gas logging display, and then calculate the total amount of after-effect released gas of the new well reservoir through steps b to e, and obtain the evaluation result in combination with the evaluation standard.

[0099] In this embodiment, according to the reservoir evaluation standard of open flow, referring to Table 2, the D layer of the P well area belongs to land and the reservoir burial depth is >4000m.

[0100] Reservoir evaluation criteria: when open flow ≤ 600m 3 / d, it is a dry layer; when 600m 3 / d<unimpeded flow ≤ 20000m 3 / d, it is a poor gas layer; when the unimpeded flow rate is greater than 20000m 3 / d, it is the air layer.

[0101] The reservoir evaluation criteria corresponding to the total amount of after-effect released gas are: when the total amount of after-effect released gas is ≤90.8, it is a dry layer; when 90.8<the total amount of after-effect released gas ≤189.4, it is a poor gas layer; when the total amount of after-effect released gas is >189.4, it is a gas layer.

[0102] Table 2: Reservoir evaluation criteria for open flow.

[0103]

[0104] According to the reservoir evaluation standard of the total amount of after-effect released gas, reservoir evaluation can be carried out on new wells, that is, first determine the reservoir location according to the gas logging display, and then calculate the total amount of after-effect released gas of the new well reservoir through steps 2 to 6, and obtain the evaluation result in combination with the evaluation standard.

[0105] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A reservoir evaluation method based on after-effect gas release, characterized in that: The following steps are involved: a. Collect the logging data, well logging data and oil testing information of specific layers of the tested wells in the study area, and select the corresponding aftereffects of the gas testing display in the test section; b. extracting the corresponding total hydrocarbon data from the screened aftereffects according to the aftereffect time; c. Standardize the extracted after-effect full hydrocarbon data in terms of base value, time interval and displacement; d. Based on the time from the onset to the end of the aftereffect, the standard total hydrocarbons are accumulated to obtain the aftereffect gas volume, and then the aftereffect gas efficiency is calculated in combination with the static time; e. Integrate the after-effect gas efficiency of multiple after-effects corresponding to the same gas test display, and fit the time difference between the occurrence time of the gas test display and the occurrence time of the after-effect to establish the after-effect gas efficiency function, and obtain the total amount of after-effect released gas displayed by the gas test; f. The open-flow rate of the tested section of the specific stratum of the tested oil wells in the study area and the total amount of after-effect released gas corresponding to the gas test display in the test section are analyzed with the standardization of the drilling fluid density to obtain the correlation function of the total amount of after-effect released gas and the open-flow rate; g. Based on the reservoir evaluation standard of open flow rate, the corresponding reservoir evaluation standard of the total amount of after-effect released gas is formed to form an evaluation method for reservoir evaluation of new wells.

2. The reservoir evaluation method based on after-effect gas release according to claim 1 is characterized in that: In step c, the total hydrocarbon TG is standardized in terms of base value, time interval and displacement according to the following formula (I): TG 标准 =(TG - TG 基值 )×t 间隔 ×V / V 标准 Equation (I), In formula (I), TG 标准 is the standard total hydrocarbon; TG is the measured total hydrocarbon; TG 基值 is the total hydrocarbon value; t 间隔 is the time interval; V is the measured displacement; V 标准 For standard displacement.

3. The reservoir evaluation method based on after-effect gas release according to claim 2 is characterized in that: In step c, the selection of the total hydrocarbon base value is mainly based on the change characteristics of the total hydrocarbon curve, and is implemented according to the after-effect description specification; the time interval is based on the actual sampling interval of the logging time data, and the time interval is 0.5 to 2 minutes; the selection of the standard displacement is mainly based on the average value of the parameters commonly used in drilling in the study area, and the standard displacement is 10 to 30L / s.

4. The reservoir evaluation method based on after-effect gas release according to claim 1 is characterized in that: In step d, the after-effect gas volume M 后效 、After-effect gas efficiency η 后效 Calculated according to the following formula (II) and (III): M 后效 =∑TG 标准 (Ⅱ); or 后效 = M 后效 / t 静止 (Ⅲ); In formula (II) and (III), M 后效 is the after-effect gas volume, η 后效 is the after-effect gas efficiency, t 静止 For still time.

5. The reservoir evaluation method based on after-effect gas release according to claim 1 is characterized in that: In step e, the post-fitting gas efficiency function is established as the following formula (IV): In formula (IV), Δt is the time difference from the occurrence time of gas measurement display to the occurrence time of aftereffect; a, b, c are fitting parameters.

6. The reservoir evaluation method based on after-effect gas release according to claim 1 is characterized in that: In step e, the function integral of the total amount of after-effect released gas is accumulated with the time difference as the axis and restored to the initial value as the cutoff, that is, the accumulation ends when the after-effect gas efficiency decreases to the initial value of the function when the time difference is zero. When f(cutoff value)=f(0), the total amount of after-effect released gas satisfies the following formula (V): Where M 后效释放 It is the total amount of gas released in the aftereffect.

7. The reservoir evaluation method based on after-effect gas release according to claim 1 is characterized in that: In step e, if there are multiple gas test displays in the test section that all have corresponding aftereffects, the total amount of aftereffect released gas displayed by the multiple gas test displays is accumulated.

8. The reservoir evaluation method based on after-effect gas release according to claim 1 is characterized in that: In step f, the correlation function between the total amount of after-effect released gas and the unimpeded flow rate is: Where, ρ is the measured drilling fluid density; ρ 标准 is the standard drilling fluid density.

9. The reservoir evaluation method based on after-effect gas release according to claim 8, characterized in that: The standard drilling fluid density was selected based on the average value of the parameters commonly used in drilling in the study area.

10. The reservoir evaluation method based on after-effect gas release according to claim 1, characterized in that: In step g, there are two reservoir evaluation criteria for unobstructed flow, one is the upper limit of dry layer, and the other is the lower limit of industrial gas flow. When the unobstructed flow rate is ≤ the upper limit of the dry layer, it is a dry layer; When the upper limit of the dry layer < unobstructed flow ≤ lower limit of industrial air flow, it is a poor air layer; When the unobstructed flow rate is greater than the lower limit of industrial air flow, it is an air layer.

11. The reservoir evaluation method based on after-effect gas release according to claim 10, characterized in that: According to the functional relationship between the total amount of after-effect released gas and the open flow rate, combined with the reservoir evaluation standard of open flow rate, the reservoir evaluation standard of the total amount of after-effect released gas is established. According to the reservoir evaluation standard of the total amount of after-effect released gas, the reservoir evaluation of the new well is carried out: First, determine the reservoir location based on the gas logging display, and then calculate the total amount of after-effect released gas in the new well reservoir through steps b to e, and combine it with the evaluation criteria to obtain the evaluation result.

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