Nitrogen column pressure prediction method and device, electronic equipment and product

Abstract

The invention discloses a nitrogen gas column pressure prediction method and device, electronic equipment and a product, and belongs to the technical field of oil and gas field development. The method comprises the following steps: obtaining a test pure nitrogen injection well pressure and a test shaft fluid density according to static flow pressure data and pure nitrogen injection well production data, and establishing a pure nitrogen injection well pressure-shaft fluid density relational expression; and according to known parameters of the pure nitrogen injection well and the pure nitrogen injection well pressure-wellbore fluid density relational expression, the wellbore gas column pressure is predicted. The method can solve the problems that an existing prediction method is tedious in calculation process, large in difficulty and large in error.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oil and gas field development, and particularly relates to a nitrogen gas column pressure prediction method and device, electronic equipment and products. BACKGROUND

[0002] In many practical problems such as gas injection well geological design, gas injection wellhead device selection, gas injection string design, wellhead gas injection pressure and gas column pressure are very important data, which are directly related to the safety of construction and gas injection. Through literature research, it is found that the current methods for calculating bottom hole pressure include Hagdorn-Brown method, average temperature and average gas deviation factor method, Aziz method and Cullender-Smith method. The mathematical models established by these methods are scientific and reasonable, but the mathematical calculation model is complex and difficult to understand, some parameters are difficult to obtain, the solving process is tedious, the calculation is difficult, and it brings certain difficulties to the popularization and application of field production analysis; and in order to simplify the derivation process, some parameters are assumed to be constant, which increases the calculation error.

[0003] Considering that the above calculation method is difficult, the currently commonly used calculation method in engineering design and construction is the accurate formula and approximate formula for calculating gas column pressure proposed by Li Shilun et al. The accurate formula considers many factors, and in order to simplify the integration process, the average value of temperature and deviation factor is taken, without considering the change with depth, and it is difficult to obtain the average compressibility of wellbore. The parameters of the approximate formula are easy to obtain, and the calculation is simple, but the influence of temperature and pressure is not considered, and the error is large when calculating high pressure and high temperature wells.

[0004] Therefore, it is urgent to invent a gas column pressure prediction method which is simple and convenient to calculate and accurate in result. SUMMARY

[0005] The purpose of the present application is to provide a nitrogen gas column pressure prediction method, device, electronic equipment and products, which solve the technical problems of the existing methods for predicting nitrogen wellbore gas column pressure, such as complicated calculation process, great difficulty and large error.

[0006] In order to achieve the above purpose, the following technical scheme is adopted:

[0007] The present application provides a nitrogen gas column pressure prediction method in the first aspect, comprising the following steps:

[0008] According to the static flow pressure data and the production data of the pure nitrogen injection well, the test pure nitrogen injection well pressure and the test wellbore fluid density are obtained, and the pure nitrogen injection well pressure-wellbore fluid density relationship is established;

[0009] According to the known parameters of the pure nitrogen injection well and the pure nitrogen injection well pressure-wellbore fluid density relationship, the wellbore gas column pressure is predicted.

[0010] In one embodiment, the test pressure of the pure nitrogen injection well includes the test wellhead injection pressure and the test intermediate-depth pressure;

[0011] The process of establishing the pressure-wellbore fluid density relationship in pure nitrogen injection wells includes:

[0012] Based on the test wellhead gas injection pressure and the test wellbore fluid density, establish the relationship between wellhead gas injection pressure and wellbore fluid density; and based on the test intermediate-depth pressure and the test wellbore fluid density, establish the relationship between intermediate-depth pressure and wellbore fluid density.

[0013] In one implementation, when the known parameters of a pure nitrogen injection well are the wellhead injection pressure, the process of predicting the wellbore gas column pressure is as follows:

[0014] By obtaining the medium-depth oil layer and combining the wellhead gas injection pressure, the relationship between wellhead gas injection pressure and wellbore fluid density, and the wellbore gas column pressure formula, the wellbore gas column pressure is predicted.

[0015] In one embodiment, the relationship between the wellhead gas injection pressure and the wellbore fluid density is as follows:

[0016] ρ1=5.5998×10 -3 P 井口 +0.13657;

[0017] In the above formula, ρ1 is the density of the wellbore fluid under the wellhead injection pressure, in g / cm³. 3 ;P 井口 The wellhead gas injection pressure is measured in MPa.

[0018] In one embodiment, the method further includes a step of predicting the intermediate-depth pressure after predicting the wellbore gas column pressure, as detailed below:

[0019] When the known parameters of a pure nitrogen injection well are the wellhead injection pressure, the intermediate-depth pressure is predicted based on the wellhead injection pressure and the predicted wellbore gas column pressure combined with the pressure relationship formula.

[0020] In one implementation, when the known parameters of a pure nitrogen injection well are medium-deep pressure, the process of predicting the wellbore gas column pressure is as follows:

[0021] By obtaining the intermediate depth of the oil reservoir and combining the intermediate depth pressure, the intermediate depth pressure-wellbore fluid density relationship, and the wellbore gas column pressure formula, the wellbore gas column pressure can be predicted.

[0022] In one embodiment, the medium-depth pressure-wellbore fluid density relationship is as follows:

[0023] ρ2=0.0037P 中深 +0.1153;

[0024] In the formula, p2 is the wellbore fluid density under the medium-depth pressure, g / cm 3 ; P 中深 is the medium-depth pressure, MPa.

[0025] In an embodiment, the method further comprises a step of predicting the predicted wellhead gas injection pressure after predicting the wellbore gas column pressure, specifically as follows:

[0026] When the known parameter is the medium-depth pressure, the wellhead gas injection pressure is predicted based on the medium-depth pressure and the predicted wellbore gas column pressure in combination with the pressure relationship formula.

[0027] In an embodiment, the step of obtaining the test wellbore fluid density is specifically as follows:

[0028] The test wellbore fluid density is obtained according to the difference between the test medium-depth pressure and the test wellhead gas injection pressure, the test oil layer medium-depth, and the wellbore fluid density formula in combination;

[0029] The wellbore fluid density formula is as follows:

[0030] p = ΔP / gΔH;

[0031] In the formula, ΔP is the difference between the test medium-depth pressure and the test wellhead gas injection pressure, MPa; g is the acceleration of gravity, a constant, 9.8 m / s 2 ; ΔH is the test oil layer medium-depth, km; and p is the wellbore fluid density, g / cm 3 .

[0032] The present application also provides a nitrogen gas column pressure prediction device, comprising:

[0033] A construction module is configured to obtain the test pure nitrogen injection well pressure and the test wellbore fluid density according to the static flow pressure data and the pure nitrogen injection well production data, and establish a pure nitrogen injection well pressure-wellbore fluid density relationship formula.

[0034] A prediction module is configured to predict the wellbore gas column pressure according to the known parameters of the pure nitrogen injection well and the pure nitrogen injection well pressure-wellbore fluid density relationship formula.

[0035] The present application provides an electronic device, comprising: a processor; and a memory coupled with the processor, the memory having stored therein instructions that, when executed by the processor, cause the electronic device to perform any of the methods.

[0036] The present application provides a computer program product tangibly stored on a non-transitory computer readable medium and comprising computer executable instructions for performing any of the methods.

[0037] Compared with the prior art, the present application has the following beneficial effects:

[0038] The present application provides a nitrogen gas column pressure prediction method, which is not dependent on complex physical models or theoretical assumptions, but directly based on static flow pressure data and production data of the pure nitrogen injection well to establish a relationship, ensuring that the relationship can truly reflect the actual relationship between the pressure of the pure nitrogen injection well and the wellbore fluid density, thereby reducing the errors caused by model simplification or inaccurate assumptions. By establishing the pressure-wellbore fluid density relationship of the pure nitrogen injection well, simple mathematical calculations can be used to predict the wellbore gas column pressure, avoiding complex physical process modeling and calculation, greatly simplifying the prediction process and reducing the error accumulation caused by complex calculation. In summary, since the relationship is established based on actual data and the prediction process is simplified, the prediction accuracy of the wellbore gas column pressure can be significantly improved, the intermediate calculation steps and variables are reduced, the error accumulation is reduced, and more reliable results are obtained. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 Flow chart of the nitrogen gas column pressure prediction method of the present application;

[0040] Figure 2 Flow chart of the nitrogen gas column pressure prediction method provided by an embodiment of the present application;

[0041] Figure 3 Flow chart of the nitrogen gas column pressure prediction method provided by another embodiment of the present application;

[0042] Figure 4 Wellhead gas injection pressure-wellbore fluid density relationship curve of the nitrogen injection well in the full oil field provided by an embodiment of the present application;

[0043] Figure 5 Medium-depth pressure-wellbore fluid density relationship curve of the nitrogen injection well in the full oil field provided by an embodiment of the present application;

[0044] Figure 6 Schematic diagram of the nitrogen gas column pressure prediction device provided by an embodiment of the present application;

[0045] Figure 7 Structural schematic diagram of the electronic device of the nitrogen gas column pressure prediction method provided by an embodiment of the present application. DETAILED DESCRIPTION

[0046] In the following, the technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort should fall within the protection scope of the present application.

[0047] It should be noted that the terms "first", "second", and the like in the description and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, device, product, or apparatus including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products, or apparatuses.

[0048] The present embodiment will be described in further detail below with reference to the drawings:

[0049] Referring to Figure 1 The present embodiment provides a nitrogen gas column pressure prediction method, comprising the following steps:

[0050] S1: obtaining the test pure nitrogen injection well pressure and the test wellbore fluid density according to the static flow pressure data and the pure nitrogen injection well production data, and establishing a pure nitrogen injection well pressure-wellbore fluid density relationship; wherein the test pure nitrogen injection well pressure includes the test wellhead gas injection pressure and the test middle-deep pressure;

[0051] S2: predicting the wellbore gas column pressure according to the known parameters of the pure nitrogen injection well and the pure nitrogen injection well pressure-wellbore fluid density relationship.

[0052] In an embodiment, the process of establishing the pure nitrogen injection well pressure-wellbore fluid density relationship comprises:

[0053] Based on the test wellhead gas injection pressure and the test wellbore fluid density, a wellhead gas injection pressure-wellbore fluid density relationship is established; and based on the test middle-deep pressure and the test wellbore fluid density, a middle-deep pressure-wellbore fluid density relationship is established.

[0054] In an embodiment, when the known parameters of the pure nitrogen injection well are the wellhead gas injection pressure, the process of predicting the wellbore gas column pressure is as follows:

[0055] By obtaining the medium-depth oil layer and combining it with the wellhead gas injection pressure, the relationship between wellhead gas injection pressure and wellbore fluid density, and the wellbore gas column pressure formula, the wellbore gas column pressure is predicted.

[0056] The relationship between the wellhead injection pressure and the wellbore fluid density is as follows:

[0057] ρ1=5.5998×10 -3 P 井口 +0.13657;

[0058] In the above formula, ρ1 is the density of the wellbore fluid under the wellhead injection pressure, in g / cm³. 3 ;P 井口 The wellhead gas injection pressure is measured in MPa.

[0059] It also includes the step of predicting intermediate-depth pressure after predicting the wellbore gas column pressure, as detailed below:

[0060] When the known parameters of a pure nitrogen injection well are the wellhead injection pressure, the intermediate-depth pressure is predicted based on the wellhead injection pressure and the predicted wellbore gas column pressure combined with the pressure relationship formula.

[0061] In one embodiment, when the known parameters of a pure nitrogen injection well are medium-deep pressure, the process of predicting the wellbore gas column pressure is as follows:

[0062] By obtaining the medium-depth oil reservoir and combining the medium-depth pressure, the medium-depth pressure-wellbore fluid density relationship, and the wellbore gas column pressure formula, the wellbore gas column pressure is predicted.

[0063] The above-mentioned relationship between medium-deep pressure and wellbore fluid density is as follows:

[0064] ρ2=0.0037P 中深 +0.1153;

[0065] In the above formula, ρ2 is the density of the wellbore fluid under medium-depth pressure, in g / cm³. 3 ;P 中深 The pressure is medium to deep, in MPa.

[0066] It also includes the step of predicting the wellhead injection pressure after predicting the wellbore gas column pressure, as follows:

[0067] When the known parameter is medium-deep pressure, the wellhead gas injection pressure is predicted based on the medium-deep pressure and the predicted wellbore gas column pressure combined with the pressure relationship formula.

[0068] In one embodiment, the step of obtaining the fluid density in the test wellbore is as follows:

[0069] The depth of the test oil layer is obtained. Based on the difference between the pressure at the test depth and the gas injection pressure at the test wellhead, and the depth of the test oil layer, the fluid density of the test wellbore is obtained using the wellbore fluid density formula.

[0070] The formula for the fluid density in the wellbore is as follows:

[0071] ρ=ΔP / gΔH;

[0072] In the above formula, ΔP is the difference between the test depth pressure and the test wellhead gas injection pressure, in MPa; g is the acceleration due to gravity, a constant, 9.8 m / s². 2 ΔH represents the depth of the tested oil layer, in km; ρ represents the fluid density in the wellbore, in g / cm³. 3 .

[0073] The pressure relationship above is as follows:

[0074] P 中深 =P 井口 +P 井筒气柱 ;

[0075] In the above formula, P 中深 For medium to deep pressure, MPa; P 井口 P represents the wellhead gas injection pressure, in MPa. 井筒气柱 The pressure is the gas column pressure in the wellbore, in MPa.

[0076] The nitrogen column pressure prediction method provided in the above embodiments has a certain scope of application: This method is based on the rules summarized from wells in the Fuman Oilfield where the drilled strata are the Yijianfang Formation-Yingshan Formation of the Ordovician, the formation pressure for gas injection is 40-60 MPa, and pure nitrogen is injected. Therefore, this method is applicable to wells injecting pure nitrogen, but not to wells injecting gas and water. Secondly, the empirical formula provided by this method may not be applicable to wells with shallow depths and formation pressures below 40 MPa or above 60 MPa, but empirical formulas for calculating nitrogen columns applicable to different formation pressure ranges and different strata can be obtained by the method provided by this invention.

[0077] In another embodiment, a method for predicting nitrogen column pressure is provided, such as... Figure 2 As shown, the specific steps are as follows:

[0078] S01: Obtain the injection pressure at the test wellhead, the test intermediate-depth pressure, and the test wellbore fluid density based on the static pressure data and the production data of the pure nitrogen injection well; establish the relationship between the injection pressure at the test wellhead and the fluid density in the test wellbore based on the injection pressure at the test wellhead and the fluid density in the test wellbore; establish the relationship between the intermediate-depth pressure and the fluid density in the test wellbore based on the test intermediate-depth pressure and the fluid density in the test wellbore.

[0079] The above steps, using actual test data, directly established the relationships between wellhead injection pressure and wellbore fluid density, as well as between intermediate-depth pressure and wellbore fluid density, avoiding complex physical process modeling and calculations, and greatly simplifying the prediction process. These relationships consider the relationship between pressure and fluid density, providing relatively accurate predictions under specific conditions (such as the Fuman oilfield). Compared to precise formulas in existing technologies, these relationships, established directly based on test data, have higher accuracy in practical applications. Because the relationships are directly based on test data, intermediate calculation steps and variables are reduced, thus decreasing error accumulation. Furthermore, since the relationships are based on actual test data, they more accurately reflect the actual situation, reducing prediction errors.

[0080] S02: Obtain known parameters, namely wellhead gas injection pressure or intermediate-depth pressure; when the known parameter is wellhead gas injection pressure, obtain the intermediate-depth of the oil layer and predict the wellbore gas column pressure by combining the relationship between wellhead gas injection pressure and wellbore fluid density and the wellbore gas column pressure formula; when the known parameter is intermediate-depth pressure, obtain the intermediate-depth of the oil layer and predict the wellbore gas column pressure by combining the relationship between intermediate-depth pressure and wellbore fluid density and the wellbore gas column pressure formula.

[0081] The formula for wellbore gas column pressure is as follows:

[0082] P 井筒气柱 =ρgH;

[0083] In the above formula, P 井筒气柱 ρ is the wellbore gas column pressure, MPa; ρ is the wellbore fluid density ρ1 at the wellbore injection pressure obtained from the wellbore injection pressure-wellbore fluid density relationship, or ρ2 at the intermediate-depth pressure obtained from the intermediate-depth pressure-wellbore fluid density relationship, g / cm³. 3 g is the acceleration due to gravity, a constant, 9.8 m / s². 2 H represents the medium depth of the oil layer, in km.

[0084] The above steps, using the known wellhead injection pressure or medium-depth pressure, combined with the corresponding wellbore fluid density relationship and wellbore gas column pressure formula, can directly predict the wellbore gas column pressure.

[0085] The process of obtaining the fluid density in the test wellbore is as follows:

[0086] Obtain the test depth pressure, test oil layer depth, and test wellhead gas injection pressure. Based on the difference between the test depth pressure and the test wellhead gas injection pressure, and the test oil layer depth, combine the wellbore fluid density formula to obtain the test wellbore fluid density.

[0087] The formula for wellbore fluid density is as follows:

[0088] ρ=ΔP / gΔH;

[0089] In the above formula, ΔP is the difference between the test depth pressure and the test wellhead gas injection pressure, in MPa; g is the acceleration due to gravity, a constant, 9.8 m / s². 2 ΔH represents the depth of the tested oil layer, in km; ρ represents the fluid density in the wellbore, in g / cm³. 3 .

[0090] The process of establishing the relationship between wellhead injection pressure and wellbore fluid density based on the test wellhead injection pressure and the test wellbore fluid density is as follows:

[0091] Based on the wellhead gas injection pressure and the wellbore fluid density, a curve showing the relationship between the wellhead gas injection pressure and the wellbore fluid density is obtained and a trend line is added. Based on the curve and trend line, a formula for the relationship between the wellhead gas injection pressure and the wellbore fluid density is established.

[0092] The process of establishing the relationship between intermediate-depth pressure and wellbore fluid density based on the tested intermediate-depth pressure and the tested wellbore fluid density is as follows:

[0093] Based on the test depth pressure and test wellbore fluid density, a test depth pressure-wellbore fluid density relationship curve is obtained and a trend line is added. Based on the test depth pressure-wellbore fluid density relationship curve and trend line, a relationship formula between depth pressure and wellbore fluid density is established.

[0094] The prediction method includes a first wellbore gas column pressure formula and a second wellbore gas column pressure formula.

[0095] The formula for the gas column pressure in the first wellbore is as follows:

[0096] P 井筒气柱 =ρ1gH;

[0097] In the above formula, P 井筒气柱 ρ1 is the wellbore gas column pressure, MPa; ρ2 is the wellbore fluid density at the wellbore injection pressure, obtained from the wellbore injection pressure-wellbore fluid density relationship, g / cm2. 3 g is the acceleration due to gravity, a constant, 9.8 m / s². 2 H represents the medium depth of the oil layer, in km.

[0098] The formula for the gas column pressure in the second wellbore is as follows:

[0099] P 井筒气柱 =ρ2gH;

[0100] In the above formula, P 井筒气柱 ρ1 is the gas column pressure in the wellbore, MPa; ρ2 is the fluid density in the wellbore at medium-depth pressure, obtained from the relationship between medium-depth pressure and wellbore fluid density, g / cm2.3 g is the acceleration due to gravity, a constant, 9.8 m / s². 2 H represents the medium depth of the oil layer, in km.

[0101] Whether the wellhead injection pressure or the medium-depth pressure is known, it can be predicted using the corresponding relationships and formulas. The above method is highly adaptable and can be applied to different wellbore conditions and fluid properties.

[0102] The nitrogen column pressure prediction method provided in the above embodiments firstly establishes a relationship between wellhead injection pressure and wellbore fluid density by directly testing the wellhead injection pressure and the wellbore fluid density. Similarly, a relationship between intermediate-depth pressure and wellbore fluid density is established based on the tested intermediate-depth pressure and the tested wellbore fluid density. When predicting the nitrogen column pressure in the wellbore, it is not necessary to consider multiple physical parameters and processes, such as temperature, gas composition, and wellbore geometry, thus avoiding complex physical process modeling and calculation, and greatly simplifying the prediction process. Establishing the relationships between wellhead injection pressure and wellbore fluid density and intermediate-depth pressure and wellbore fluid density using actual test data ensures the accuracy and reliability of the relationships. Secondly, combining information on the intermediate depth of the oil reservoir, the wellbore gas column pressure formula, and the pressure relationship further improves the accuracy of the prediction, reduces intermediate calculation steps and variables, and reduces the accumulation of errors. The above method is simple to operate and the calculation results have relatively small errors. The obtained wellbore gas column pressure can be used to calculate the wellhead gas injection pressure or medium-deep pressure, providing a basis for the geological design of gas injection wells, the selection of gas injection wellhead equipment, and the design of gas injection tubing.

[0103] In another embodiment, a method for predicting nitrogen gas column pressure is provided, such as... Figure 3 As shown, it includes the following steps:

[0104] Log in to a well testing database (V3.1.0) of a certain oilfield to obtain static pressure data during gas injection in the gas injection well;

[0105] Based on the hydrostatic pressure data, the following data were compiled: hydrostatic pressure test date, test well number, test depth pressure, test depth of oil layer, and test depth temperature.

[0106] Log in to the Oil, Gas and Water Well Production Data Management System (V2.0.0) to obtain the gas injection pressure and wellhead temperature of the gas injection well corresponding to the date of the static pressure test for the gas injection single well;

[0107] Calculate the fluid density in the test wellbore based on the depth of the tested oil layer, the pressure at the tested depth, and the gas injection pressure at the test wellhead.

[0108] Establish the relationship between pressure and wellbore fluid density in pure nitrogen injection wells. The relationship between pressure and wellbore fluid density in pure nitrogen injection wells includes the relationship between wellhead injection pressure and wellbore fluid density and the relationship between medium-deep pressure and wellbore fluid density.

[0109] Determine the known parameters of the pure nitrogen injection well, and select the corresponding pure nitrogen injection well pressure-wellbore fluid density relationship to predict the wellbore gas column pressure.

[0110] Specifically, the test wellbore fluid density is obtained by combining the difference between the test depth pressure and the test wellhead gas injection pressure, the test oil layer depth, and the wellbore fluid density formula.

[0111] The formula for wellbore fluid density is as follows:

[0112] ρ=ΔP / gΔH;

[0113] In the above formula, ΔP is the difference between the test depth pressure and the test wellhead gas injection pressure, in MPa; g is the acceleration due to gravity, a constant, 9.8 m / s². 2 ΔH represents the depth of the tested oil layer, in km; ρ represents the fluid density in the wellbore, in g / cm³. 3 Furthermore, the above formula is derived from ΔP=ρgΔH.

[0114] Based on existing data, draw the following diagram: Figure 4 The scatter plot of wellhead injection pressure versus wellbore fluid density shows a very good linear relationship; a trend line was added, with the trend line option selected as linear, R... 2 =0.9945, obtain the relationship L1 between wellhead injection pressure and wellbore fluid density in the Fuman oilfield nitrogen injection well:

[0115] ρ1=5.5998×10 -3 P 井口 +0.13657;

[0116] In the formula: ρ1 is the density of the wellbore fluid under the wellhead injection pressure, in g / cm³. 3 ;P 井口 The wellhead gas injection pressure is measured in MPa.

[0117] When the injection pressure at the wellhead of a nitrogen injection well is known, and the deep pressure and gas column pressure in the wellbore are predicted, the known injection pressure at the wellhead can be substituted into L1 to calculate the fluid density ρ1 in the wellbore under this injection pressure.

[0118] Then, according to the formula for the first wellbore gas column pressure P 井筒气柱 =ρ1gH, and the wellbore gas column pressure under this wellhead gas injection pressure can be calculated;

[0119] In the above formula, P 井筒气柱 ρ1 is the wellbore gas column pressure, MPa; ρ2 is the wellbore fluid density at the wellbore injection pressure, obtained from the wellbore injection pressure-wellbore fluid density relationship, g / cm2. 3 g is the acceleration due to gravity, a constant, 9.8 m / s².2 H represents the medium depth of the oil layer, in km;

[0120] According to the pressure relationship P 中深 =P 井口 +P 井筒气柱 The forecast indicates that the pressure will be moderate to deep.

[0121] In the above formula, P 中深 For medium to deep pressure, MPa; P 井口 P represents the wellhead gas injection pressure, in MPa. 井筒气柱 The pressure is the gas column pressure in the wellbore, in MPa.

[0122] Based on existing data, draw the following diagram: Figure 5 The scatter plot of medium-depth pressure versus wellbore fluid density shows a very good linear relationship; a trend line was added, with the trend line option selected as linear, R... 2 =0.9919, obtain the deep pressure-wellbore fluid density relationship L2 of nitrogen injection wells in the Fuman oilfield:

[0123] ρ2=0.0037P 中深 +0.1153;

[0124] In the above formula, ρ2 is the density of the wellbore fluid under medium-depth pressure, in g / cm³. 3 ;P 中深 The pressure is medium to deep, in MPa.

[0125] When the medium-depth pressure of a nitrogen injection well is known, and the injection pressure at the wellhead and the gas column pressure in the wellbore are predicted, the known medium-depth pressure can be substituted into L2 to calculate the fluid density ρ2 in the wellbore under this medium-depth pressure.

[0126] Then, based on the second wellbore gas column pressure P 井筒气柱 =ρ2gH, and the wellbore gas column pressure under this medium-depth pressure can be calculated;

[0127] In the above formula, P 井筒气柱 ρ1 is the gas column pressure in the wellbore, MPa; ρ2 is the fluid density in the wellbore at medium-depth pressure, obtained from the relationship between medium-depth pressure and wellbore fluid density, g / cm2. 3 g is the acceleration due to gravity, a constant, 9.8 m / s². 2 H represents the medium depth of the oil layer, in km;

[0128] According to the pressure relationship P 井口 =P 中深 -P 井筒气柱 The wellhead gas injection pressure is predicted and obtained.

[0129] In the above formula: P 中深 For medium to deep pressure, MPa; P 井口P represents the wellhead gas injection pressure, in MPa. 井筒气柱 The pressure is the gas column pressure in the wellbore, in MPa.

[0130] When the injection pressure at the wellhead of a nitrogen injection well is known, and the intermediate-depth pressure and the gas column pressure in the wellbore are predicted:

[0131] HD302-H2 and HD302H have good connectivity. Gas injection began in HD302H well on April 20, 2023, while HD302-H2 produced oil. The oil layer in HD302H well is 7065.18m deep, and the gas injection pressure at the wellhead of HD302H well was 32MPa on October 15, 2023.

[0132] According to the method provided in this embodiment, the predicted wellbore gas column pressure at this time is:

[0133] P 井筒气柱 =(5.5998÷1000×32+0.13657)×9.8×7065.18÷1000=21.86MPa;

[0134] The predicted deep pressure in well HD302H at this time is: P HD302中深 =32 + 21.86 = 53.86 MPa;

[0135] On October 15, 2023, the static temperature and pressure gradient of well HD302-H2 was tested. This test reached a depth of 6700m (51.45MPa, 139.47℃). The average static pressure gradient in the 6600-6700m well section was 0.63MPa / 100m. Based on the static temperature and pressure gradient of well HD302-H2, the predicted pressure at this mid-depth point in HD302H2 is:

[0136] P (根据HD302-H2静梯预测HD302H中深) =(7065.18-6700)×0.63÷100+51.45=53.75MPa;

[0137] Relative error = (53.86 - 53.75) ÷ 53.75 = 0.21%;

[0138] Table 1. Predicted intermediate-depth pressure and wellbore gas column pressure from known nitrogen injection wellhead pressures.

[0139]

[0140] The calculated intermediate-depth pressure in this embodiment has a relative error of only 0.21% compared to the actual intermediate-depth pressure. When the intermediate-depth pressure of a nitrogen injection well is known, and the wellhead injection pressure and wellbore gas column pressure are predicted:

[0141] On December 9, 2023, the static temperature and static pressure gradient of well ZG29-2 was tested. The oil layer depth was 5984.25m, and the static pressure at this depth was 54.48MPa. Based on the method in this embodiment, the wellbore gas column pressure under this pressure was predicted as follows:

[0142] P 井筒气柱 =(0.0037×54.48+0.1153)×9.8×5984.25÷1000=18.58MPa;

[0143] The predicted wellhead gas injection pressure for well ZG29-2 under this pressure is: P (ZG29-2井口) =54.48-18.58=35.90MPa;

[0144] On October 9, 2023, nitrogen injection in well ZG29-2 was stopped, at which time the wellhead injection pressure was 38.8 MPa. From October 9, 2023 to December 9, 2023, well ZG29-2 was only injected with 200 cubic meters of water to pressure the well after the gas injection was completed. The well was shut off for the rest of the time. Therefore, it is assumed that the medium-deep pressure on October 9 and December 9 was basically the same. Thus, the actual gas injection pressure at the wellhead under the medium-deep pressure was 34.8 MPa.

[0145] Relative error = (35.90 - 34.80) ÷ 34.80 = 3.75%.

[0146] The relative error between the calculated wellhead injection pressure and the actual wellhead injection pressure in this embodiment is 3.75%.

[0147] Table 2. Predicted wellhead injection pressure and wellbore gas column pressure for known deep nitrogen injection wells.

[0148]

[0149] Because the test data during the injection of pure nitrogen gas wells is limited and has been used to regress empirical formulas, the evaluation of the invention's effectiveness takes into account that if there is no well production, water injection, or gas injection during the static pressure test-injection and injection-injection-static pressure test periods, the formation pressure changes are minimal. Therefore, static pressure data tested before or after injection, such as those from wells ZG431-H5, ZG29-2, and ZG262-H4C in the Tazhong No. 1 gas field, are used. If static pressure data before injection is used, the wellhead injection pressure corresponding to the medium-deep pressure is the pressure at the beginning of injection; if static pressure data after injection is used... The wellhead injection pressure corresponding to the medium-deep pressure is the pressure at the end of injection. On the other hand, for connected well groups such as the HD302H well group, HD302H and HD302-H2 have good connectivity, and the medium-deep pressure of the injection well HD302H can be estimated based on the static pressure data of HD302-H2. It is known that the relative error of the wellhead injection pressure prediction of the medium-deep pressure of nitrogen injection wells is within 2%, and the prediction of the medium-deep pressure and the gas column pressure in the wellbore is accurate. It is known that the relative error of the wellhead injection pressure prediction of the medium-deep pressure of nitrogen injection wells is within 4%, and the prediction of the wellhead injection pressure and the gas column pressure in the wellbore is accurate.

[0150] The calculation method provided in the background technology is applied to the Fuman Oilfield, which has a medium depth of 6234-8274m, a medium-depth temperature of 141.3-186.6℃, and a medium-depth pressure of 72.0-97.3MPa. The Fuman Oilfield is a high-temperature and high-pressure carbonate reservoir. The relative error between the approximate method and the precise method in calculating the nitrogen injection gas column pressure in the Fuman Oilfield is more than 8%. However, the prediction error of the prediction method used in this embodiment is much less than 8%. Therefore, the above prediction method solves the technical problem of large calculation and prediction errors in the prior art.

[0151] In one embodiment, such as Figure 6 As shown, a nitrogen gas column pressure prediction device is also provided, including a construction module and a prediction module, wherein the specific contents of the construction module and the prediction module are as follows:

[0152] The module is used to obtain the test pressure of the pure nitrogen injection well and the test wellbore fluid density based on static pressure data and pure nitrogen injection well production data, and to establish the relationship between the pure nitrogen injection well pressure and the wellbore fluid density.

[0153] The prediction module is used to predict the wellbore gas column pressure based on the known parameters of the pure nitrogen injection well and the pressure-wellbore fluid density relationship.

[0154] More specifically, based on the above embodiments, the nitrogen gas column pressure prediction device includes a construction module and a prediction module. The construction module is used to obtain the test wellhead injection pressure, test intermediate-depth pressure, and test wellbore fluid density based on hydrostatic pressure data and pure nitrogen injection well production data; establish a wellhead injection pressure-wellbore fluid density relationship based on the test wellhead injection pressure and test wellbore fluid density; and establish an intermediate-depth pressure-wellbore fluid density relationship based on the test intermediate-depth pressure and test wellbore fluid density. The prediction module is used to obtain known parameters, which are either the wellhead injection pressure or the intermediate-depth pressure; when the known parameter is the wellhead injection pressure, it obtains the intermediate-depth of the oil layer and, combined with the wellhead injection pressure-wellbore fluid density relationship and the wellbore gas column pressure formula, predicts the wellbore gas column pressure; when the known parameter is the intermediate-depth pressure, it obtains the intermediate-depth of the oil layer and, combined with the intermediate-depth pressure-wellbore fluid density relationship and the wellbore gas column pressure formula, predicts the wellbore gas column pressure.

[0155] The module for obtaining the test wellbore fluid density is specifically used to obtain the test wellbore fluid density in the following manner:

[0156] The depth of the test oil layer is obtained. Based on the difference between the pressure at the test depth and the gas injection pressure at the test wellhead, and the depth of the test oil layer, the fluid density of the test wellbore is obtained using the wellbore fluid density formula.

[0157] The formula for the wellbore fluid density is as follows:

[0158] ρ=ΔP / gΔH;

[0159] In the above formula, ΔP is the difference between the test depth pressure and the test wellhead gas injection pressure, in MPa; g is the acceleration due to gravity, a constant, 9.8 m / s². 2 ΔH represents the depth of the tested oil layer, in km; ρ represents the fluid density in the wellbore, in g / cm³. 3 .

[0160] The module for establishing the relationship between wellhead injection pressure and wellbore fluid density is specifically used to establish the relationship between wellhead injection pressure and wellbore fluid density in the following manner:

[0161] Based on the test wellhead gas injection pressure and test wellbore fluid density, obtain the test wellhead gas injection pressure-wellbore fluid density relationship curve and add a trend line. Based on the test wellhead gas injection pressure-wellbore fluid density relationship curve and trend line, establish the wellhead gas injection pressure-wellbore fluid density relationship formula.

[0162] The relationship between wellhead gas injection pressure and wellbore fluid density is as follows:

[0163] ρ1=5.5998×10 -3 P 井口 +0.13657;

[0164] In the above formula, ρ1 is the density of the wellbore fluid under the wellhead injection pressure, in g / cm³. 3 ;P 井口 The wellhead gas injection pressure is measured in MPa.

[0165] The module for establishing the relationship between medium-depth pressure and wellbore fluid density is specifically used to establish the relationship between medium-depth pressure and wellbore fluid density in the following manner:

[0166] Based on the test depth pressure and test wellbore fluid density, a test depth pressure-wellbore fluid density relationship curve is obtained and a trend line is added. Based on the test depth pressure-wellbore fluid density relationship curve and trend line, a relationship formula between depth pressure and wellbore fluid density is established.

[0167] The relationship between medium-deep pressure and wellbore fluid density is as follows:

[0168] ρ2=0.0037P 中深 +0.1153;

[0169] In the above formula, ρ2 is the density of the wellbore fluid under medium-depth pressure, in g / cm³. 3 ;P 中深 The pressure is medium to deep, in MPa.

[0170] The wellhead gas injection pressure prediction module is used to predict medium-deep pressure based on the wellhead gas injection pressure and the predicted wellbore gas column pressure, when the known parameter is the wellhead gas injection pressure.

[0171] The medium-depth pressure prediction module is used to predict the wellhead gas injection pressure based on the medium-depth pressure and the predicted wellbore gas column pressure, combined with the pressure relationship formula, when the known parameter is medium-depth pressure.

[0172] In one embodiment, the present invention provides an electronic device including: a processor; and a memory coupled to the processor, the memory having instructions stored therein, the instructions, when executed by the processor, causing the electronic device to perform any of the methods described herein. Figure 7 A schematic diagram of an electronic device 10 that can be used to implement embodiments of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (e.g., helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0173] like Figure 7As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded from storage unit 18 into the RAM 13. The RAM 13 may also store various programs and data required for the operation of the electronic device 10. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0174] Multiple components in electronic device 10 are connected to I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of displays, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, wireless transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0175] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as the nitrogen gas column pressure prediction method.

[0176] In some embodiments, the nitrogen column pressure prediction method may be implemented as a computer program product tangibly contained in a non-transient computer-readable medium, such as storage unit 18. In some embodiments, part or all of the computer program product may be loaded and / or installed on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the method for constructing the three-dimensional numerical model of the core described above may be performed. Alternatively, in other embodiments, processor 11 may be configured to perform the nitrogen column pressure prediction method by any other suitable means (e.g., by means of firmware).

[0177] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0178] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0179] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0180] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for predicting nitrogen gas column pressure, characterized in that, Includes the following steps: Based on static pressure data and production data of pure nitrogen injection wells, the test pressure and test wellbore fluid density of pure nitrogen injection wells were obtained, and the relationship between pure nitrogen injection well pressure and wellbore fluid density was established. Predict the wellbore gas column pressure based on the known parameters of the pure nitrogen injection well and the pressure-wellbore fluid density relationship.

2. The nitrogen column pressure prediction method according to claim 1, characterized in that, The test pressure for pure nitrogen injection wells includes the test wellhead injection pressure and the test intermediate-depth pressure. The process of establishing the pressure-wellbore fluid density relationship in pure nitrogen injection wells includes: Based on the test wellhead gas injection pressure and the test wellbore fluid density, establish the relationship between wellhead gas injection pressure and wellbore fluid density; and based on the test intermediate-depth pressure and the test wellbore fluid density, establish the relationship between intermediate-depth pressure and wellbore fluid density.

3. The nitrogen column pressure prediction method according to claim 2, characterized in that, When the known parameters of a pure nitrogen injection well are the wellhead injection pressure, the process of predicting the wellbore gas column pressure is as follows: By obtaining the medium-depth oil layer and combining the wellhead gas injection pressure, the relationship between wellhead gas injection pressure and wellbore fluid density, and the wellbore gas column pressure formula, the wellbore gas column pressure is predicted.

4. The nitrogen column pressure prediction method according to claim 2 or 3, characterized in that, The relationship between wellhead gas injection pressure and wellbore fluid density is as follows: p1=5.5998×10 -3 P 井口 +0.13657; In the above formula, ρ1 is the density of the wellbore fluid under the wellhead injection pressure, in g / cm³. 3 ;P 井口 The wellhead gas injection pressure is measured in MPa.

5. The nitrogen column pressure prediction method according to claim 3, characterized in that, It also includes the step of predicting intermediate-depth pressure after predicting the wellbore gas column pressure, as detailed below: When the known parameters of a pure nitrogen injection well are the wellhead injection pressure, the intermediate-depth pressure is predicted based on the wellhead injection pressure and the predicted wellbore gas column pressure combined with the pressure relationship formula.

6. The nitrogen column pressure prediction method according to claim 2, characterized in that, When the known parameters of a pure nitrogen injection well are medium-deep pressure, the process of predicting the wellbore gas column pressure is as follows: By obtaining the intermediate depth of the oil reservoir and combining the intermediate depth pressure, the intermediate depth pressure-wellbore fluid density relationship, and the wellbore gas column pressure formula, the wellbore gas column pressure can be predicted.

7. The nitrogen column pressure prediction method according to claim 2 or 6, characterized in that, The relationship between medium-deep pressure and wellbore fluid density is as follows: ρ2=0.0037P 中深 +0.1153; In the above formula, ρ2 is the density of the wellbore fluid under medium-depth pressure, in g / cm³. 3 ;P 中深 The pressure is medium to deep, in MPa.

8. The nitrogen column pressure prediction method according to claim 6, characterized in that, It also includes the step of predicting the wellhead injection pressure after predicting the wellbore gas column pressure, as follows: When the known parameter is medium-deep pressure, the wellhead gas injection pressure is predicted based on the medium-deep pressure and the predicted wellbore gas column pressure combined with the pressure relationship formula.

9. The nitrogen column pressure prediction method according to claim 2, characterized in that, The steps for obtaining the fluid density in the test wellbore are as follows: The depth of the test oil layer is obtained, and the fluid density of the test wellbore is obtained by combining the difference between the pressure at the test depth and the gas injection pressure at the test wellhead, the depth of the test oil layer, and the fluid density formula in the wellbore. The formula for the wellbore fluid density is as follows: ρ=ΔP / gΔH; In the above formula, ΔP is the difference between the test depth pressure and the test wellhead gas injection pressure, in MPa; g is the acceleration due to gravity, a constant, 9.8 m / s². 2 ΔH represents the depth of the tested oil layer, in km; ρ represents the fluid density in the wellbore, in g / cm³. 3 .

10. A nitrogen gas column pressure prediction device, characterized in that, include: The module is used to obtain the test pressure of the pure nitrogen injection well and the test wellbore fluid density based on static pressure data and pure nitrogen injection well production data, and to establish the relationship between the pure nitrogen injection well pressure and the wellbore fluid density. The prediction module is used to predict the wellbore gas column pressure based on the known parameters of the pure nitrogen injection well and the pressure-wellbore fluid density relationship.

11. An electronic device, comprising: processor; And a memory coupled to the processor, the memory having instructions stored therein, which, when executed by the processor, cause the electronic device to perform the method according to any one of claims 1 to 9.

12. A computer program product tangibly stored on a non-transient computer-readable medium and comprising computer-executable instructions for performing the method according to any one of claims 1 to 9.

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