A method for obtaining the empirical formula of one-point method based on exponential expression

Abstract

The present invention discloses a method for obtaining an exponential one-point empirical formula, comprising: substituting component data of a target gas reservoir into a well test interpretation software, and drawing a curve of the relationship between μZ and p; judging the pressure range of the target gas reservoir according to the gas reservoir pressure of the target gas reservoir; determining the expression form of the production capacity equation according to the pressure range of the gas reservoir; calculating the exponential production capacity equation empirical coefficients of each production capacity test well of the gas reservoir according to the seepage coefficient, seepage index, and open flow rate of each production capacity test well of the gas reservoir; averaging the exponential production capacity equation empirical coefficients and seepage index of each production capacity test well of the gas reservoir, and substituting them into the expression form of the determined production capacity equation to obtain the exponential one-point empirical formula of the target gas reservoir. The present invention overcomes the problem of insufficient accuracy of the traditional one-point binomial one-point production capacity empirical formula based on the square form of pressure in the evaluation of gas well production capacity in medium and high pressure gas reservoirs, and enriches the scope of application of the one-point production capacity well test to evaluate gas well production capacity.

Description

Technical Field

[0001] The invention relates to a method for obtaining an exponential-based one-point empirical formula, and belongs to the field of petroleum engineering. Background Art

[0002] In the field of natural gas development, effective assessment of gas well productivity is crucial for achieving rational production allocation and efficient development. Accurate productivity assessment not only provides scientific guidance for gas reservoir development but also optimizes gas well production plans, improves resource extraction efficiency, and reduces development costs. The first step in evaluating gas well productivity is conducting a gas well productivity test. This test can determine dynamic parameters such as gas well production rate and pressure. Further analysis and interpretation of the test data allows the actual productivity of the gas well to be determined, assessing its development potential and production capacity. Currently, four main types of gas well productivity testing methods exist: backpressure testing, isochronous testing, modified isochronous testing, and single-point testing. The single-point productivity test, due to its simplicity and time efficiency, has become an important tool for evaluating gas well productivity. The accuracy of gas well productivity assessment using this single-point testing method depends on the applicability of the empirical formula used. If the formula is not suitable for the target gas reservoir, the calculated open-flow rate will differ significantly from the actual open-flow rate. For a specific gas reservoir, an empirical formula for unimpeded flow at one point that is suitable for that reservoir should be studied. Therefore, it is of great significance to study different forms of one-point capacity formulas and enrich the scope of application of one-point capacity formulas. Traditional one-point capacity formulas are all established using the method of Chen Yuanqian's one-point formula, and are all based on the binomial one-point capacity formula in the form of pressure squared. The structural forms of gas well capacity equations mainly include binomial and exponential forms. Both binomial and exponential capacity equations are widely used in the calculation and evaluation of gas well capacity in various oil and gas reservoirs. However, currently, only relevant research results are available for the binomial one-point capacity formula. There is no relevant theoretical derivation and relevant empirical formula based on the exponential one-point capacity formula, nor is there a one-point capacity formula based on pseudo-pressure and pressure forms. This seriously restricts the accurate evaluation of gas well test capacity in gas reservoirs. Summary of the Invention

[0003] The purpose of the present invention is to address the problems existing in the prior art and provide a method for obtaining an exponential-based one-point empirical formula. This method theoretically derives the structural form of the exponential one-point capacity formula of a gas well for the first time, and at the same time derives the one-point capacity formula based on the pressure form, the pressure square form and the pseudo-pressure form, which makes up for the problem of insufficient accuracy of the traditional binomial one-point capacity empirical formula based on the pressure square form in the production capacity evaluation of medium and high-pressure gas reservoir exploration wells, and enriches the scope of application of the one-point capacity test to evaluate the production capacity of gas wells.

[0004] The present invention provides a technical solution to solve the above technical problems: a method for obtaining an exponential one-point empirical formula, comprising the following steps:

[0005] Step S10: Substitute the component data of the target gas reservoir into the well test interpretation software, calculate the natural gas viscosity μ and deviation factor Z under different pressure conditions p, and draw a curve of the relationship between μZ and p;

[0006] Step S20, dividing the pressure range in the curve of the relationship between μZ and p into pressure interval I, pressure interval II, and pressure interval III, and determining the pressure interval where the target gas reservoir is located based on the gas reservoir pressure of the target gas reservoir;

[0007] Step S30: determining the expression form of the production capacity equation according to the pressure range of the gas reservoir;

[0008] Step S40: Obtain the permeability coefficient C, permeability index n and open flow rate q of each productivity test well in the gas reservoir according to the productivity test interpretation results of each productivity test well in the gas reservoir. AOF ;

[0009] Step S50: Based on the permeability coefficient C, permeability index n and open flow rate q of each gas reservoir production test well, AOF Calculate the empirical coefficient α of the exponential productivity equation for each productivity test well in the gas reservoir;

[0010] Step S60: average the empirical coefficient α and the seepage index n of the exponential productivity equation of each productivity test well in the gas reservoir, and substitute them into the expression of the productivity equation determined in step S30 to obtain the exponential one-point empirical formula of the target gas reservoir.

[0011] A further technical solution is that in step S20, a first pressure point and a second pressure point are determined in the curve of the relationship between μZ and p; if the reservoir pressure of the target gas reservoir is less than the first pressure point, the pressure interval in which the target gas reservoir is located is pressure interval I; if the reservoir pressure of the target gas reservoir is greater than or equal to the first pressure point and less than or equal to the second pressure point, the pressure interval in which the target gas reservoir is located is pressure interval II; if the reservoir pressure of the target gas reservoir is greater than the second pressure point, the pressure interval in which the target gas reservoir is located is pressure interval III.

[0012] A further technical solution is that the process of determining the first pressure point in step S20 is: taking the pressure value corresponding to 1.05 times the starting point μZ value in the μZ vs. p change relationship curve as the first pressure point value.

[0013] A further technical solution is that the process of determining the second pressure point in step S20 is: fitting the curve of the relationship between μZ and p to obtain a curve fitting formula; then derivatizing the curve fitting formula, and setting the second-order derivative to 0, calculating the x value, and the x value is the second pressure point value.

[0014] A further technical solution is that in step S30, if the gas reservoir pressure is in region I, the production capacity equation is suitable for expression in pseudo-pressure form and pressure square form; if the gas reservoir pressure is in region II, the production capacity equation is only suitable for expression in pseudo-pressure form; if the gas reservoir pressure is in region III, the production capacity equation is suitable for expression in pseudo-pressure form and pressure form.

[0015] A further technical solution is that the exponential one-point method empirical formula of the pseudo-pressure form in step S30 is:

[0016]

[0017] Where: R is the pseudo pressure of gas reservoir, MPa 2 / (mPa·s); ψ wf is the pseudo bottom hole pressure of the gas well, MPa 2 / (mPa·s);q AOF is the unobstructed flow rate; α is the empirical coefficient of the exponential capacity equation; q sc is the gas well production under standard conditions, 10 4 m 3 / d.

[0018] A further technical solution is that the exponential one-point empirical formula of the pressure form in step S30 is:

[0019]

[0020] Where: p R is the gas reservoir pressure, MPa; p wf is the bottom hole flowing pressure of the gas well, MPa; q AOF is the unobstructed flow rate; α is the empirical coefficient of the exponential capacity equation; q sc is the gas well production under standard conditions, 10 4 m 3 / d.

[0021] A further technical solution is that the exponential one-point empirical formula of the pressure square form in step S30 is:

[0022]

[0023] Where: p R is the gas reservoir pressure, MPa; p wf is the bottom hole flowing pressure of the gas well, MPa; q AOF is the unobstructed flow rate; α is the empirical coefficient of the exponential capacity equation; q sc is the gas well production under standard conditions, 10 4 m 3 / d.

[0024] A further technical solution is that the calculation formula of the empirical coefficient α of the exponential capacity equation is:

[0025]

[0026] Where: q AOF is the unobstructed flow rate; C is the seepage coefficient; n is the seepage index; α is the empirical coefficient of the exponential capacity equation.

[0027] The beneficial effects of the present invention are as follows: the present invention breaks through the limitations of the traditional binomial one-point method productivity empirical formula in the square form of pressure in terms of equation structure, and enriches the productivity evaluation method of exploration test gas wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The relationship curve between μZ and p and the schematic diagram of pressure partition;

[0029] Figure 2 Figure 2 is the relationship curve between μZ and p and the schematic diagram of pressure zones for gas reservoir X. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0031] The present invention provides a method for obtaining an exponential-based one-point empirical formula, comprising the following steps:

[0032] Step S10: Substitute the component data of the target gas reservoir into the well test interpretation software, calculate the natural gas viscosity μ and deviation factor Z under different pressure p conditions, and draw a curve of the relationship between μZ and p (such as Figure 1 shown);

[0033] Step S20, dividing the pressure range in the curve of the relationship between μZ and p into pressure interval I, pressure interval II, and pressure interval III, and determining the pressure interval where the target gas reservoir is located based on the gas reservoir pressure of the target gas reservoir;

[0034] The pseudo-pressure of natural gas is defined as:

[0035]

[0036] Where: ψ is the natural gas pseudo-pressure function, MPa 2 / (mPa·s); p is the natural gas pressure, MPa. p0 is the reference pressure (usually atmospheric pressure), MPa; μ is the natural gas viscosity, mPa·s. Z is the natural gas deviation factor, dimensionless.

[0037] According to the different pressure limits of gas reservoirs, the pressure is divided into three different pressure intervals: low, medium and high, which are represented by regions I, II and III respectively. Figure 1 As shown;

[0038] Specifically, the first pressure point and the second pressure point are determined in the curve of the relationship between μZ and p; if the reservoir pressure of the target gas reservoir is less than the first pressure point, the pressure interval in which the target gas reservoir is located is pressure interval I; if the reservoir pressure of the target gas reservoir is greater than or equal to the first pressure point and less than or equal to the second pressure point, the pressure interval in which the target gas reservoir is located is pressure interval II; if the reservoir pressure of the target gas reservoir is greater than the second pressure point, the pressure interval in which the target gas reservoir is located is pressure interval III.

[0039] Depend on Figure 1 It can be seen that at the beginning of the curve, the curve is approximately a horizontal line. μZ hardly changes with changes in p and is approximately constant. The μZ value at the end of this part is similar to the μZ value at the starting point. Therefore, this part is defined as Region I. The end of Region I is 1.05 times the μZ value at the starting point. In this way, the increase in μZ value is only 5%, and the Region I curve can still be regarded as an approximately horizontal line. Within Region I, the pseudo-pressure of natural gas can be simplified to the square of the pressure:

[0040]

[0041] Where: (μZ)c is the product of μ and Z, which is a constant, mPa·s.

[0042] Depend on Figure 1 It can be seen that at the end of the curve, the curve approximates a straight line with a constant slope. μZ and p are linearly related, and p / (μZ) is a constant. Therefore, this area is defined as Region III. The starting point of Region III is the inflection point of the curve, that is, the point where the curvature is zero (taking the second-order derivative of the curve and setting it equal to 0, from which the coordinates of the corresponding point are calculated). In this way, the Region III curve can be regarded as an approximate straight line with a constant slope. Within Region III, the pseudo-pressure of natural gas can be simplified to the pressure form:

[0043]

[0044] Where: (p / (μZ))c is p divided by μZ, a constant, MPa / mPa·s.

[0045] Step S30: determining the expression form of the production capacity equation according to the pressure range of the gas reservoir;

[0046] If the gas reservoir pressure is located in region I, the productivity equation is suitable to be expressed in pseudo-pressure form and pressure square form;

[0047] If the gas reservoir pressure is located in region II, the productivity equation is only suitable for expression in pseudo-pressure form;

[0048] If the gas reservoir pressure is located in region III, the productivity equation is suitable for expression in pseudo-pressure form and pressure form;

[0049] The structural form of the gas well exponential one-point productivity formula is derived based on the exponential productivity equation. The derivation process is as follows:

[0050] The exponential capacity equation is:

[0051] q sc =C(ξ R -ξ wf ) n (4)

[0052] Where ξ is a formal variable related to pressure; R is the formal variable under gas reservoir pressure conditions; ξ wf is the formal variable under bottom hole flow pressure conditions; q sc is the gas well production under standard conditions, 10 4 m 3 / d; C is the seepage coefficient; n is the seepage index.

[0053] For low-pressure gas reservoirs, ξ=p 2 ; For high-pressure gas reservoirs, ξ=p; for gas reservoirs in any pressure range, ξ=ψ.

[0054] When wf = 0, the gas well production is the absolute unobstructed flow rate, and formula (4) becomes:

[0055] q AOF =C(ξ R ) n (5)

[0056] Where q AOF is the absolute unobstructed flow rate of the gas well, 10 4 m 3 / d.

[0057] Multiplying formula (4) by formula (5) yields:

[0058] q sc q AOF =C(ξ R -ξ wf ) n ·C(ξ R ) n (6)

[0059] Formula (6) is transformed to get:

[0060]

[0061] The empirical coefficients of the exponential capacity equation are defined as:

[0062]

[0063] Substituting formula (10) into formula (9), we can get the exponential one-point method unobstructed flow calculation formula:

[0064]

[0065] For low-pressure gas reservoirs, Equation (11) can be written as:

[0066]

[0067] Where p R is the gas reservoir pressure, MPa; p wf is the bottom hole flowing pressure of the gas well, MPa.

[0068] For high-pressure gas reservoirs, Equation (11) can be written as:

[0069]

[0070] For gas reservoirs in any pressure range, Equation (11) can be written as:

[0071]

[0072] Where: R is the pseudo pressure of gas reservoir, MPa 2 / (mPa·s); ψ wf is the pseudo bottom hole pressure of the gas well, MPa 2 / (mPa·s).

[0073] Equations (12)–(14) are the exponential one-point capacity formulas expressed in pressure square form, pressure form, and pseudo-pressure form, respectively.

[0074] Step S40: Obtain the permeability coefficient C, permeability index n and open flow rate q of each productivity test well in the gas reservoir according to the productivity test interpretation results of each productivity test well in the gas reservoir. AOF ;

[0075] Step S50: Based on the permeability coefficient C, permeability index n and open flow rate q of each gas reservoir production test well, AOF Calculate the empirical coefficient α of the exponential productivity equation for each productivity test well in the gas reservoir;

[0076] Step S60: averaging the empirical coefficient α and the seepage index n of the exponential productivity equation of each productivity test well of the gas reservoir, and substituting the average values into the expression of the productivity equation determined in step S30 to obtain the exponential one-point empirical formula of the target gas reservoir;

[0077] Step S70, substitute the formation pressure, bottomhole flowing pressure and gas production data of the gas reservoir production well (when applying the pseudo-pressure form empirical formula, the formation pressure and bottomhole flowing pressure need to be converted into pseudo-formation pressure and pseudo-bottomhole flowing pressure) into the exponential one-point method empirical formula of the gas reservoir to obtain the unobstructed flow rate of the well. Applying this formula can greatly speed up the gas reservoir production capacity testing work speed and realize efficient and reasonable production allocation of gas wells.

[0078] Example

[0079] The present invention will be further described in detail below using a deep high-pressure gas reservoir in the Tarim Basin (referred to as gas reservoir X) as an example.

[0080] Step S10: The composition data of gas reservoir X is shown in Table 1. Substituting the composition data of gas reservoir X into the well test interpretation software, the natural gas viscosity μ and deviation factor Z under different pressure conditions can be calculated;

[0081] Table 1 Gas reservoir X natural gas composition data

[0082] Components composition(%) Components composition(%) <![CDATA[C1]]> 97.597 <![CDATA[nC5]]> 0.001 <![CDATA[C2]]> 0.669 <![CDATA[C6]]> 0.001 <![CDATA[C3]]> 0.024 <![CDATA[C 7+ ]]> 0 <![CDATA[iC4]]> 0.002 <![CDATA[CO2]]> 0.88 <![CDATA[nC4]]> 0.004 <![CDATA[N2]]> 0.82 <![CDATA[iC5]]> 0.002 / /

[0083] Step S20: Based on the previously calculated natural gas viscosity μ, deviation factor Z and pressure p data, a curve of the relationship between μZ and p is drawn, such as Figure 2 As shown;

[0084] Step S30: Divide the pressure into three different pressure intervals: low, medium, and high, according to different pressure limits of the gas reservoir X, and represent them as regions I, II, and III respectively;

[0085] Step S301: Figure 2 As shown, at the beginning of the curve, the curve is approximately a horizontal line. μZ hardly changes with changes in p and is approximately constant. The μZ value at the end of this section is similar to the μZ value at the starting point. Therefore, this area is defined as Region I. The μZ value at the starting point of Region I is 0.015090762, corresponding to a pressure of 0. The end point of Region I is 1.05 times the μZ value at the starting point, that is, the μZ value at the end point is 0.015090762 × 1.05 = 0.01584555, corresponding to a pressure of 10.88 MPa. In this way, the curve of Region I can still be regarded as an approximately horizontal line. Within Region I, the pseudo-pressure of natural gas can be simplified to the square of the pressure.

[0086] Step S302: Figure 2As shown in the figure, at the end of the curve, the curve is approximately a straight line with a certain slope. μZ is linearly related to p, and p / (μZ) is a constant. Therefore, this part of the area is defined as area III. The starting point of area III is the inflection point of the curve, that is, the point where the curvature is zero. The fitted curve formula is:

[0087] y=-0.0000000207x 3 +0.0000060078x 2 +0.0001071919x+0.0142204942 (15)

[0088] Taking the second-order derivative of formula (15) we get:

[0089] y″=-0.0000001242x+0.0000120156 (16)

[0090] Let y″ = 0, and we get x = 96.74 MPa. Then the inflection point of the curve, i.e. the starting point of region III, is 96.74 MPa. Thus, the curve of region III can be regarded as a straight line with a certain slope. In region III, the pseudo-pressure of natural gas can be simplified to the pressure form;

[0091] Step S40: Gas reservoir X has an average burial depth of 7132 m, an original gas reservoir pressure of 108.91 MPa, and a gas reservoir temperature of 166.5°C. The gas reservoir pressure of 108.91 MPa is greater than 96.74 MPa. Therefore, the pressure range of the gas reservoir is determined to be region III. Therefore, the production capacity equation of gas reservoir X is suitable for expression in both pseudo-pressure form and pressure form.

[0092] Step S50: sort out the interpretation results of the productivity test wells of gas reservoir X, and determine the seepage coefficient C, seepage index n and open flow rate q of the productivity test wells of gas reservoir X in the form of well pressure and pseudo pressure. AOF , according to formula (10), the empirical coefficient α of the two pressure forms of well pressure and pseudo pressure of each productivity test well is determined, and the results are shown in Table 2;

[0093] Table 2 Interpretation results of 7 productivity test wells in gas reservoir X

[0094]

[0095]

[0096] Step S60: Take the average values of the empirical coefficient α and the seepage index n of the two pressure forms of the well pressure and the pseudo-pressure of each productivity test well of gas reservoir X, and substitute them into equations (13) and (14) respectively to obtain the exponential one-point method empirical formula of gas reservoir X based on the pressure and pseudo-pressure forms;

[0097] The empirical formula of the exponential one-point method based on the pressure form of gas reservoir X is:

[0098]

[0099] The exponential one-point empirical formula of gas reservoir X based on pseudo-pressure form is:

[0100]

[0101] Step S70: Substitute the formation pressure, bottom hole flowing pressure, and gas production data of each productivity test well of gas reservoir X into equations (17) and (18) for back-calculation (when applying the pseudo-pressure form empirical formula, the formation pressure and bottom hole flowing pressure need to be converted into pseudo-formation pressure and pseudo-bottom hole flowing pressure). The errors between the calculated results of the empirical formula for each well and the measured results are shown in Table 3. The average back-calculation errors of the exponential one-point method productivity empirical formulas in the pressure form and the pseudo-pressure form are 2.84% and 3.04%, respectively, proving that the empirical formulas are accurate and reliable.

[0102] Table 3 Open flow rate and error calculation results of different empirical formulas for 7 productivity test wells of gas reservoir X

[0103]

[0104]

[0105] Step S80: The formation pressure of a production well A in gas reservoir X is 102.47 MPa, the bottom hole pressure is 89.21 MPa, the gas production is 598,400 cubic meters per day, and the pseudo formation pressure is 292,771.14 MPa. 2 / (mPa·s), the simulated bottom hole pressure is 254885.46MPa 2 Substituting these data into the exponential one-point empirical formula for this gas reservoir, the open-flow rate for the well was calculated to be 1.7736 million cubic meters per day using the pressure-based exponential one-point empirical formula and 1.8101 million cubic meters per day using the pseudo-pressure-based exponential one-point empirical formula. Applying this formula can significantly accelerate gas reservoir productivity testing and achieve efficient and rational production allocation for gas wells.

[0106] The above description does not limit the present invention in any form. Although the present invention has been disclosed through the above embodiments, it is not intended to limit the present invention. Any technician familiar with the profession can use the technical content disclosed above to make some changes or modifications to equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for obtaining an exponential one-point empirical formula, characterized in that: The following steps are involved: Step S10: Substitute the component data of the target gas reservoir into the well test interpretation software, calculate the natural gas viscosity μ and deviation factor Z under different pressure conditions p, and draw a curve of the relationship between μZ and p; Step S20, dividing the pressure range in the curve of the relationship between μZ and p into pressure interval I, pressure interval II, and pressure interval III, and determining the pressure interval where the target gas reservoir is located based on the gas reservoir pressure of the target gas reservoir; Step S30: determining the expression form of the production capacity equation according to the pressure range of the gas reservoir; Step S40: Obtain the permeability coefficient C, permeability index n and open flow rate q of each productivity test well in the gas reservoir according to the productivity test interpretation results of each productivity test well in the gas reservoir. AOF ; Step S50: Based on the permeability coefficient C, permeability index n and open flow rate q of each gas reservoir production test well, AOF Calculate the empirical coefficient α of the exponential productivity equation for each productivity test well in the gas reservoir; Step S60: average the empirical coefficient α and the seepage index n of the exponential productivity equation of each productivity test well in the gas reservoir, and substitute them into the expression of the productivity equation determined in step S30 to obtain the exponential one-point empirical formula of the target gas reservoir.

2. The method for obtaining an exponential-based one-point empirical formula according to claim 1, characterized in that: In step S20, a first pressure point and a second pressure point are determined in the curve of the relationship between μZ and p; if the reservoir pressure of the target gas reservoir is less than the first pressure point, the pressure interval in which the target gas reservoir is located is pressure interval I; if the reservoir pressure of the target gas reservoir is greater than or equal to the first pressure point and less than or equal to the second pressure point, the pressure interval in which the target gas reservoir is located is pressure interval II; if the reservoir pressure of the target gas reservoir is greater than the second pressure point, the pressure interval in which the target gas reservoir is located is pressure interval III.

3. The method for obtaining an exponential-based one-point empirical formula according to claim 1, wherein: The process of determining the first pressure point in step S20 is as follows: in the curve of the relationship between μZ and p, the pressure value corresponding to 1.05 times the value of the starting point μZ is taken as the first pressure point value.

4. The method for obtaining an exponential-based one-point empirical formula according to claim 1, wherein: The process of determining the second pressure point in step S20 is as follows: fitting the curve of the relationship between μZ and p to obtain a curve fitting formula; then differentiating the curve fitting formula and setting the second-order derivative to 0 to calculate the x value, which is then the second pressure point value.

5. The method for obtaining an exponential-based one-point empirical formula according to claim 1, wherein: In step S30, if the gas reservoir pressure is in region I, the production capacity equation is suitable for expression in pseudo-pressure form and pressure square form; if the gas reservoir pressure is in region II, the production capacity equation is only suitable for expression in pseudo-pressure form; if the gas reservoir pressure is in region III, the production capacity equation is suitable for expression in pseudo-pressure form and pressure form.

6. The method for obtaining an exponential-based one-point empirical formula according to claim 5, characterized in that: The exponential one-point empirical formula of the pseudo-pressure form in step S30 is: Where: R is the pseudo pressure of gas reservoir, MPa 2 / (mPa·s); ψ wf is the pseudo bottom hole pressure of the gas well, MPa 2 / (mPa·s);q AOF is the unobstructed flow rate; α is the empirical coefficient of the exponential capacity equation; q sc is the gas well production under standard conditions, 10 4 m 3 / d.

7. The method for obtaining an exponential-based one-point empirical formula according to claim 5, characterized in that: The exponential one-point empirical formula of the pressure form in step S30 is: Where: p R is the gas reservoir pressure, MPa; p wf is the bottom hole flowing pressure of the gas well, MPa; q AOF is the unobstructed flow rate; α is the empirical coefficient of the exponential capacity equation; q sc is the gas well production under standard conditions, 10 4 m 3 / d.

8. The method for obtaining an exponential-based one-point empirical formula according to claim 5, characterized in that: The exponential one-point empirical formula of the pressure square form in step S30 is: Where: p R is the gas reservoir pressure, MPa; p wf is the bottom hole flowing pressure of the gas well, MPa; q AOF is the unobstructed flow rate; α is the empirical coefficient of the exponential capacity equation; q sc is the gas well production under standard conditions, 10 4 m 3 / d.

9. The method for obtaining an exponential-based one-point empirical formula according to claim 1, characterized in that: The calculation formula of the empirical coefficient α of the exponential capacity equation is: Where: q AOF is the unobstructed flow rate; C is the seepage coefficient; n is the seepage index; α is the empirical coefficient of the exponential capacity equation.

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