CN113449408A - Stratum pressure calculation method and device for shale gas well - Google Patents
Stratum pressure calculation method and device for shale gas well Download PDFInfo
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Abstract
The invention provides a formation pressure calculation method for a shale gas well, which comprises the following steps: the method comprises the following steps: establishing a stratum pressure calculation model for the shale gas well based on the sensitive elements according to the drilling data of the drilled wells in the same area; step two: arranging element logging data of the target well, and calculating to obtain the difference between the sensitive element envelope line and the sensitive element baseline of the target well to obtain a difference value; step three: and substituting the difference value into a formation pressure calculation model, and calculating in real time to obtain the formation pressure or pressure coefficient of the target well. The invention adopts element logging data widely used by shale gas wells, establishes a relation model with the formation pressure by selecting elements sensitive to rock pore volume parameters and rock pore fluid volume parameters, realizes the purpose of real-time, continuous and accurate calculation of the formation pressure of the shale gas through the element logging data, and overcomes the theoretical inadaptability, parameter inadaptability and method inadaptability of the current formation pressure calculation through dc index.
Description
Technical Field
The invention relates to the technical field of petroleum engineering, in particular to a method and a device for calculating formation pressure of a shale gas well.
Background
Generally, the main principle used for calculating the formation pressure while drilling is under-compaction theory, the main parameters are dc index or Sigma index, and the main method is the Eton method or the ratio method.
In the prior art, the eaton method is widely applied in the gulf area of the united states, is developed on the basis of the hubert and weilis theories, and holds a view that: it is believed that the subterranean formation is filled with formations, joints and fractures and that the well fluid pressure merely invades along these fractures, causing them to open up. Thus, the fluid pressure that opens the fracture need only overcome the ground stress normal to the fracture face.
The eaton method is only suitable for a continuous sedimentary basin such as gulf of mexico where the stratum deposition is new and the influence of the tectonic movement is small, and the prediction effect is poor for an area where the stratum age is old and the influence of the tectonic movement is large.
In the prior art, a ratio method assumes that the ratio between the actual value of a curve and the normal trend line value at the same depth point of an under-compacted interval is in a proportional relation with the formation pressure. The calculation formula is as follows:
Pa＝Pn*Datn/Dato
in the formula: pa is the formation pressure gradient of the actual depth point;
pn is the pressure gradient on the normal trend line at the same depth;
datn-the data value on the normal trend line;
dato is the actual value of the data curve.
For shale gas formations, the inadaptation of the eaton method or the ratio method is achieved in three aspects:
firstly, the principle is not suitable, the pressure cause of the shale gas formation is complex, and the more important pressure cause is hydrocarbon generation and structural extrusion besides under compaction;
secondly, parameters are not suitable, the shale gas adopts a horizontal well drilling process, and engineering parameters are greatly influenced;
thirdly, the method is not suitable, and the compaction trend line of the horizontal well is difficult to accurately determine.
Therefore, the field logging does not basically provide pressure data of the shale gas stratum, in the prior art, a certain shale gas horizontal well provides a pressure coefficient calculated by a dc index of 1.39 at most, and a stratum pressure coefficient of fracturing test gas is 1.91, so that the error is large.
Therefore, the invention provides a formation pressure calculation method and device for a shale gas well.
Disclosure of Invention
In order to solve the problems, the invention provides a formation pressure calculation method for a shale gas well, which comprises the following steps:
the method comprises the following steps: establishing a stratum pressure calculation model for the shale gas well based on the sensitive elements according to the drilling data of the drilled wells in the same area;
step two: arranging element logging data of a target well, and calculating to obtain a difference between a sensitive element envelope line and a sensitive element baseline of the target well to obtain a difference value;
step three: and substituting the difference value into the formation pressure calculation model, and calculating in real time to obtain the formation pressure or the pressure coefficient of the target well.
According to an embodiment of the present invention, the step one specifically includes the following steps: collecting the drilled element logging data, gas logging data, engineering parameter logging data, logging data and fracturing gas testing data.
According to an embodiment of the present invention, the step one specifically includes the following steps:
analyzing the correlation of each element in the rock sample with the rock pore volume parameter and the rock pore fluid volume parameter based on the drilled well data;
and aiming at each element in the rock sample, sorting the elements according to the relevance from high to low, and selecting two or more elements which are jointly sensitive to the rock pore volume parameter and the rock pore fluid volume parameter as the sensitive elements.
According to one embodiment of the invention, the rock pore volume parameter comprises: porosity, density, dc index.
According to one embodiment of the invention, the rock pore fluid volume parameter comprises: total hydrocarbons, gas content, gas saturation.
According to an embodiment of the present invention, the step one specifically includes the following steps: and establishing a formation pressure or pressure coefficient solving equation as the formation pressure calculation model by taking the formation pressure or pressure coefficient as a vertical coordinate and the combination of the sensitive elements as a horizontal coordinate based on the drilled well data.
According to an embodiment of the present invention, the second step specifically includes the following steps: and determining the sensitive element envelope curve and the sensitive element baseline by taking the well depth as a horizontal axis and the combination of the sensitive elements as a vertical axis, wherein the sensitive element baseline is parallel to the horizontal axis.
According to an embodiment of the present invention, in the second step, the difference is calculated by the following formula:
Δ(M1/M2)＝(M1/M2)envelope curve-(M1/M2)Base line
Wherein Δ (M1/M2) represents the difference, M1 represents the first sensitive element, M2 represents the second sensitive element, (M1/M2)Envelope curveRepresents the sensitive element curve envelope (M1/M2)Base lineRepresenting the sensitive element curve baseline.
According to an embodiment of the present invention, in the third step, the formation pressure or pressure coefficient of the target well is calculated by the following formula:
P＝a×Δ(M1/M2)+b
wherein P represents a formation pressure or pressure coefficient of the target well, a represents a first coefficient, and b represents a second coefficient.
According to another aspect of the present invention, there is also provided a formation pressure calculation apparatus for a shale gas well, the apparatus comprising:
the formation pressure modeling module is used for establishing a formation pressure calculation model for the shale gas well based on the sensitive elements according to the drilling data of the drilled wells in the same area;
the difference value calculation module is used for sorting element logging data of a target well, calculating to obtain the difference between the sensitive element envelope curve of the target well and the sensitive element baseline, and obtaining a difference value;
and the formation pressure calculation module is used for substituting the difference value into the formation pressure calculation model and calculating the formation pressure or the pressure coefficient of the target well in real time.
According to one embodiment of the invention, the formation pressure modeling module comprises: and the data collection unit is used for collecting the drilled element logging data, the gas logging data, the engineering parameter logging data, the logging data and the fracturing gas testing data.
According to one embodiment of the invention, the formation pressure modeling module comprises:
a correlation unit for analyzing the correlation of each element in the rock sample with the rock pore volume parameter and the rock pore fluid volume parameter based on the drilled well data;
and the sensitive element selection unit is used for sorting each element in the rock sample from high to low according to the relevance and selecting two or more elements which are jointly sensitive to the rock pore volume parameter and the rock pore fluid volume parameter as the sensitive elements.
According to one embodiment of the invention, the formation pressure modeling module comprises: and the model establishing unit is used for establishing a formation pressure or pressure coefficient solving equation as the formation pressure calculation model by taking the formation pressure or pressure coefficient as a vertical coordinate and the combination of the sensitive elements as a horizontal coordinate based on the drilled well data.
According to an embodiment of the present invention, the difference calculation module includes: and the sensitive element curve unit is used for determining the sensitive element envelope curve and the sensitive element baseline by taking the well depth as a horizontal axis and taking the combination of the sensitive elements as a vertical axis, wherein the sensitive element baseline is parallel to the horizontal axis.
According to an embodiment of the present invention, the difference calculation module includes a first calculation unit that calculates the difference by the following formula:
Δ(M1/M2)＝(M1/M2)envelope curve-(M1/M2)Base line
Wherein Δ (M1/M2) represents the difference, M1 represents the first sensitive element, M2 represents the second sensitive element, (M1/M2)Envelope curveRepresents the sensitive element curve envelope (M1/M2)Base lineRepresenting the sensitive element curve baseline.
The invention provides a method and a device for calculating the formation pressure of a shale gas well, which adopt element logging data widely used by the shale gas well, establish a relation model with the formation pressure by selecting elements sensitive to rock pore volume parameters and rock pore fluid volume parameters together, realize the purpose of real-time, continuous and accurate calculation of the formation pressure of the shale gas through the element logging data, and overcome the theoretical inadaptability, parameter inadaptability and method inadaptability of the formation pressure calculated through dc indexes at present.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 shows a flow chart of a formation pressure calculation method for a shale gas well according to an embodiment of the present invention;
FIG. 2 shows an all hydrocarbon, dc index and S/Al comparison plot according to one embodiment of the present invention;
FIG. 3 shows a graph of a formation pressure calculation model according to an embodiment of the invention;
FIG. 4 shows a plot of an (S/Al) curve analysis of a region X page Y-1HF well according to one embodiment of the invention; and
fig. 5 shows a block diagram of a formation pressure calculation apparatus for a shale gas well according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention are described in further detail below with reference to the accompanying drawings.
The method can overcome the inadaptability of calculating the formation pressure of the shale gas horizontal well by the dc index, and directly calculates the pressure coefficient by selecting the elements which are sensitive to the volume parameter of the rock pore and the volume parameter of the rock pore fluid.
Because stratum elements contain abundant geological information and element logging is a relatively mature and widely used shale gas evaluation technology, the method provided by the invention is simple to operate, low in cost, accurate in calculation and wider in application range.
FIG. 1 shows a flow chart of a method for formation pressure calculation for shale gas wells in accordance with an embodiment of the present invention.
Referring to fig. 1, in step S101, a formation pressure calculation model for shale gas wells based on sensitive elements is built according to drilling data of drilled wells in the same area.
Specifically, in step S101, the drilled element logging data, gas logging data, engineering parameter logging data, and fracturing gas testing data are collected.
In one embodiment, in step S101, the sensitive element is selected by:
first, the correlation between each element in the rock sample and the rock pore volume parameter and the rock pore fluid volume parameter is analyzed based on the drilled well data.
Then, aiming at each element in the rock sample, sorting the elements according to the relevance from high to low, and selecting two or more elements which are jointly sensitive to the volume parameter of the rock pore space and the volume parameter of the rock pore space fluid as the sensitive elements.
Specifically, the rock pore volume parameters include: porosity, density, dc index.
Specifically, the rock pore fluid volume parameters include: total hydrocarbons, gas content, gas saturation.
Generally, there are two main types of causes of formation pressure: one is the change in rock pore volume; one is the change in rock pore fluid volume.
In one embodiment, as can be seen from table 1, the elements sensitive to dc index, porosity, density and total hydrocarbon are S, Al and K, and since Al and K both reflect the content of clay minerals and have better correlation, the Al element having higher correlation with the content of clay minerals and the S element reflecting the content of organic matters are selected as the sensitive elements of the formation pressure, and the combination of the sensitive elements is represented by the (S/Al) ratio.
TABLE 1 stratum sensitive element table
In one embodiment, when the sensitive elements are S and Al, the total hydrocarbon, the dc index and the (S/Al) ratio are compared, and fig. 2 is a pilot hole section, it can be seen that when drilling, the dc index is greatly influenced by drilling coring, and the formation pressure is difficult to calculate through the dc index; the real gas containing condition of the stratum is difficult to reflect under the influence of engineering parameters such as drilling time and the like, and the (S/Al) ratio is very consistent with the fluid abundance of the nuclear magnetic resonance logging in the change trend.
Therefore, the method can overcome the inadaptability of calculating the formation pressure of the shale gas horizontal well by the dc index, directly calculates the pressure coefficient by selecting the elements sensitive to the volume parameter of the rock pore and the volume parameter of the rock pore fluid, and has higher precision compared with the prior art.
In one embodiment, in step S101, based on the drilling data of the drilled well, a formation pressure or pressure coefficient is used as an ordinate, and a combination of the sensitive elements is used as an abscissa, and a formation pressure or pressure coefficient solving equation is established as the formation pressure calculation model.
Fig. 3 shows a graph of the variation of the increase in the pressure coefficient and the (S/Al) ratio, and in order to establish the formation pressure calculation model, based on the drilled well data, the pressure coefficient is used as the ordinate, the combination of the sensitive elements (here, the sensitive elements are S and Al) is used as the abscissa, and the fitting function Y is 0.0084X +1.7601 as the formation pressure calculation model.
FIG. 3 shows the correlation analysis of the formation pressure coefficient of the well fracturing gas and the (S/Al) amplitude difference of logging elements, wherein the correlation coefficient reaches 0.93, the absolute error of the pressure coefficient does not exceed 0.032, and the accuracy is high.
As shown in fig. 1, in step S102, element logging data of the target well is sorted, and a difference between an envelope of a sensitive element of the target well and a baseline of the sensitive element is calculated to obtain a difference.
In one embodiment, in step S102, the sensitive element envelope and the sensitive element baseline are determined by taking the well depth as the horizontal axis and the combination of the sensitive elements as the vertical axis, wherein the sensitive element baseline is parallel to the horizontal axis.
In one embodiment, in step S102, the difference is calculated by the following formula:
Δ(M1/M2)＝(M1/M2)envelope curve-(M1/M2)Base line
Wherein, Delta (M1/M2) represents difference, M1 represents first sensitive element, M2 represents second sensitive element, (M1/M2)Envelope curveRepresents the sensitive element curve envelope (M1/M2)Base lineRepresenting the baseline of the sensitive element curve.
As shown in fig. 1, in step S103, the difference is substituted into the formation pressure calculation model, and the formation pressure or pressure coefficient of the target well is calculated in real time.
In one embodiment, in step S103, the formation pressure or pressure coefficient of the target well is calculated by the following formula:
P＝a×Δ(M1/M2)+b
where P represents the formation pressure or pressure coefficient of the target well, a represents the first coefficient, and b represents the second coefficient.
FIG. 4 shows a plot of an (S/Al) curve analysis of a region X page Y-1HF well, according to one embodiment of the invention. In one embodiment, X page Y-1HF wells are selected as target wells. And selecting S as a first sensitive element and Al as a second sensitive element.
The method comprises the following steps of (I) establishing a stratum pressure calculation model for the shale gas well based on sensitive elements according to the drilling data of the drilled well in the same region with a target well:
(a) collecting the well-drilled element logging data, gas logging data, engineering parameter logging data, logging data and fracturing gas testing data.
(b) Analyzing the correlation between each element of the rock sample and rock pore volume parameters (such as porosity, density and dc index) and rock pore fluid volume parameters (such as total hydrocarbon, gas content and gas saturation), sorting the elements according to the correlation number from high to low, and selecting two elements (such as S, Al) or a plurality of elements (such as Table 1) which are sensitive to the parameters.
(c) For a drilled well in the same region, an equation for solving the formation pressure or the pressure coefficient (pressure gradient) of the fracturing test gas is established by taking the formation pressure or the pressure coefficient (pressure gradient) as the ordinate and Δ (S/Al) as the abscissa (as shown in fig. 3), and a formation pressure calculation model is as follows:
P＝0.0084*Δ(S/Al)+1.7601
wherein, P represents the pressure coefficient, the first coefficient value is 0.0084, and the second coefficient value is 1.7601.
(II) collating the element logging data of the target well, calculating to obtain the difference between the sensitive element envelope line and the sensitive element baseline of the target well, and obtaining a difference value:
(d) and determining a base line and an envelope line of the (S/Al) ratio by taking the well depth as a horizontal coordinate and the (S/Al) ratio as a vertical coordinate, wherein the determined positions of the base line and the envelope line are consistent, if both the base line and the envelope line are taken as a low point or a middle point, the base line is parallel to a horizontal axis.
Kerogen contains S element, Al element represents clay mineral content, and the (S/Al) ratio represents organic matter content in clay mineral, and has better consistency with pore fluid saturation (as shown in figure 2). The peak of the (S/Al) ratio is caused by the S element in pyrite, so the baseline, envelope values are taken.
(e) The formation pressure depth provided by the fracturing test gas is pressed, and the difference value of the envelope curve (or average line and smooth line) of the ratio of the corresponding depth (S/Al) and the baseline is read:
Δ(S/Al)＝(S/Al)envelope curve-(S/Al)Base line
Wherein Δ (S/Al) represents a difference (S/Al)Envelope curveRepresents the sensitive element curve envelope (S/Al)Base lineIndicating a sensitive element curve baseline, S indicating a first sensitive element, and Al indicating a second sensitive element.
And (III) substituting the difference value into a formation pressure calculation model, and calculating in real time to obtain the formation pressure or pressure coefficient of the target well:
(f) and calculating the formation pressure or pressure coefficient of the target well by the following formula:
P＝0.0084*Δ(S/Al)+1.7601
wherein, P represents the formation pressure or pressure coefficient of the target well, the first coefficient value is 0.0084, and the second coefficient value is 1.7601.
As shown in figure 4, the pressure of the X page Y-1HF well fracturing test gas at the vertical depth of 3735.91m in the middle of the well zone is calculated to be 75.58MPa according to the pressure of the adjacent well zone, and the pressure coefficient is 2.02. According to the measured well deviation data, the deviation depth of the vertical depth 3735.91m is 4900m (as shown in fig. 4), the weighted average value of the depth (S/Al) is about 32%, the base line value (S/Al) is about 3%, so that the amplitude difference of (S/Al) is 29%, the calculated pressure coefficient is 2.00 by substituting the formula of a formation pressure calculation model, the calculated pressure coefficient is consistent with the pressure coefficient estimated by fracturing gas testing, and the absolute error is 0.02.
Fig. 5 shows a block diagram of a formation pressure calculation apparatus for a shale gas well according to an embodiment of the present invention.
As shown in fig. 5, the formation pressure calculation apparatus 500 includes: a formation pressure modeling module 501, a difference calculation module 502, and a formation pressure calculation module 503. The formation pressure modeling module 501 includes: the data collection unit 5011, the correlation unit 5012, the sensitive element selection unit 5013, and the model building unit 5014. The difference calculation module 502 includes: a sensitive element curve unit 5021 and a first calculation unit 5022. The formation pressure calculation module 503 comprises a second calculation unit 5031.
Specifically, the formation pressure modeling module 501 is configured to build a formation pressure calculation model for a shale gas well based on sensitive elements according to drilling data of drilled wells in the same area.
In one embodiment, the data collection unit 5011 is used to collect drilled elemental log data, gas log data, engineering parameter log data, well log data, and fracture test gas data.
In one embodiment, the correlation unit 5012 is used to analyze the correlation of each element in the rock sample with the rock pore volume parameter and the rock pore fluid volume parameter based on the drilled well data.
In one embodiment, the sensitive element selecting unit 5013 is configured to select two or more elements which are sensitive to both the rock pore volume parameter and the rock pore fluid volume parameter as the sensitive elements in the order of high correlation to low correlation for each element in the rock sample.
In one embodiment, the model building unit 5014 is configured to build a formation pressure or pressure coefficient solving equation as the formation pressure calculation model based on the drilled well data, with the formation pressure or pressure coefficient as an ordinate and the combination of the sensitive elements as an abscissa.
Specifically, the difference calculation module 502 is configured to sort the element logging data of the target well, and calculate a difference between the sensitive element envelope and the sensitive element baseline of the target well to obtain a difference.
In one embodiment, the sensate profile unit 5021 is configured to determine an envelope of the sensate and a baseline of the sensate with the depth of the well as the horizontal axis and the combination of the sensates as the vertical axis, wherein the baseline of the sensate is parallel to the horizontal axis.
In one embodiment, the first calculation unit 5022 calculates the difference value by the following formula:
Δ(M1/M2)＝(M1/M2)envelope curve-(M1/M2)Base line
Wherein, Delta (M1/M2) represents difference, M1 represents first sensitive element, M2 represents second sensitive element, (M1/M2)Envelope curveRepresents the sensitive element curve envelope (M1/M2)Base lineRepresenting the baseline of the sensitive element curve.
Specifically, the formation pressure calculation module 503 is configured to substitute the difference value into the formation pressure calculation model, and calculate in real time to obtain the formation pressure or pressure coefficient of the target well.
In one embodiment, the second calculation unit 5031 calculates the formation pressure or pressure coefficient of the target well by the following formula:
P＝a×Δ(M1/M2)+b
where P represents the formation pressure or pressure coefficient of the target well, a represents the first coefficient, and b represents the second coefficient.
In summary, the method and the device for calculating the formation pressure of the shale gas well provided by the invention adopt element logging data widely used by the shale gas well, establish a relation model with the formation pressure by selecting elements sensitive to rock pore volume parameters and rock pore fluid volume parameters together, realize the purpose of real-time, continuous and accurate calculation of the formation pressure of the shale gas through the element logging data, overcome the theoretical inadaptability, parameter inadaptability and method inadaptability of the formation pressure calculated through dc indexes at present, the formation elements contain abundant geological information, and the element logging is a mature technology with few factors influenced by drilling conditions, so the method and the device are simple to operate, low in cost, accurate in calculation and wider in application range.
It is to be understood that the disclosed embodiments of the invention are not limited to the particular structures, process steps, or materials disclosed herein but are extended to equivalents thereof as would be understood by those ordinarily skilled in the relevant arts. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.
Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrase "one embodiment" or "an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment.
Although the embodiments of the present invention have been described above, the above description is only for the convenience of understanding the present invention, and is not intended to limit the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (15)
1. A method for formation pressure calculation for shale gas wells, the method comprising the steps of:
the method comprises the following steps: establishing a stratum pressure calculation model for the shale gas well based on the sensitive elements according to the drilling data of the drilled wells in the same area;
step two: arranging element logging data of a target well, and calculating to obtain a difference between a sensitive element envelope line and a sensitive element baseline of the target well to obtain a difference value;
step three: and substituting the difference value into the formation pressure calculation model, and calculating in real time to obtain the formation pressure or the pressure coefficient of the target well.
2. The method of claim 1, wherein the first step comprises the steps of: collecting the drilled element logging data, gas logging data, engineering parameter logging data, logging data and fracturing gas testing data.
3. The method of claim 1, wherein the first step comprises the steps of:
analyzing the correlation of each element in the rock sample with the rock pore volume parameter and the rock pore fluid volume parameter based on the drilled well data;
and aiming at each element in the rock sample, sorting the elements according to the relevance from high to low, and selecting two or more elements which are jointly sensitive to the rock pore volume parameter and the rock pore fluid volume parameter as the sensitive elements.
4. The method of claim 3, wherein the rock pore volume parameter comprises: porosity, density, dc index.
5. The method of claim 3, wherein the rock pore fluid volume parameter comprises: total hydrocarbons, gas content, gas saturation.
6. The method of claim 1, wherein the first step comprises the steps of: and establishing a formation pressure or pressure coefficient solving equation as the formation pressure calculation model by taking the formation pressure or pressure coefficient as a vertical coordinate and the combination of the sensitive elements as a horizontal coordinate based on the drilled well data.
7. The method of claim 1, wherein the second step specifically comprises the steps of: and determining the sensitive element envelope curve and the sensitive element baseline by taking the well depth as a horizontal axis and the combination of the sensitive elements as a vertical axis, wherein the sensitive element baseline is parallel to the horizontal axis.
8. The method of claim 1, wherein in step two, the difference is calculated by the following formula:
△(M1/M2)＝(M1/M2)envelope curve-(M1/M2)Base line
Wherein Δ (M1/M2) represents the difference, M1 represents the first sensitive element, M2 represents the second sensitive element, (M1/M2)Envelope curveRepresents the sensitive element curve envelope (M1/M2)Base lineRepresenting the sensitive element curve baseline.
9. The method of claim 8, wherein in step three, the formation pressure or pressure coefficient of the target well is calculated by the following formula:
P＝a×△(M1/M2)+b
wherein P represents a formation pressure or pressure coefficient of the target well, a represents a first coefficient, and b represents a second coefficient.
10. A formation pressure calculation device for a shale gas well, the device comprising:
the formation pressure modeling module is used for establishing a formation pressure calculation model for the shale gas well based on the sensitive elements according to the drilling data of the drilled wells in the same area;
the difference value calculation module is used for sorting element logging data of a target well, calculating to obtain the difference between the sensitive element envelope curve of the target well and the sensitive element baseline, and obtaining a difference value;
and the formation pressure calculation module is used for substituting the difference value into the formation pressure calculation model and calculating the formation pressure or the pressure coefficient of the target well in real time.
11. The apparatus of claim 10, wherein the formation pressure modeling module comprises: and the data collection unit is used for collecting the drilled element logging data, the gas logging data, the engineering parameter logging data, the logging data and the fracturing gas testing data.
12. The apparatus of claim 10, wherein the formation pressure modeling module comprises:
a correlation unit for analyzing the correlation of each element in the rock sample with the rock pore volume parameter and the rock pore fluid volume parameter based on the drilled well data;
and the sensitive element selection unit is used for sorting each element in the rock sample from high to low according to the relevance and selecting two or more elements which are jointly sensitive to the rock pore volume parameter and the rock pore fluid volume parameter as the sensitive elements.
13. The apparatus of claim 10, wherein the formation pressure modeling module comprises: and the model establishing unit is used for establishing a formation pressure or pressure coefficient solving equation as the formation pressure calculation model by taking the formation pressure or pressure coefficient as a vertical coordinate and the combination of the sensitive elements as a horizontal coordinate based on the drilled well data.
14. The apparatus of claim 10, wherein the difference calculation module comprises: and the sensitive element curve unit is used for determining the sensitive element envelope curve and the sensitive element baseline by taking the well depth as a horizontal axis and taking the combination of the sensitive elements as a vertical axis, wherein the sensitive element baseline is parallel to the horizontal axis.
15. The apparatus of claim 10, wherein the difference calculation module comprises a first calculation unit that calculates the difference by the following equation:
△(M1/M2)＝(M1/M2)envelope curve-(M1/M2)Base line
Wherein Δ (M1/M2) represents the difference, M1 represents the first sensitive element, M2 represents the second sensitive element, (M1/M2)Envelope curveRepresents the sensitive element curve envelope (M1/M2)Base lineRepresenting the sensitive element curve baseline.
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