Evaluation method for index of water-mixed flow process gathering system in oilfield

Abstract

The present application relates to the oilfield ground engineering oil and gas gathering and transportation technical field, especially relates to an oilfield water mixing process gathering and transportation system index evaluation method.The oilfield water mixing process gathering and transportation system index evaluation method comprises the following steps: step one, a gathering and transportation system mechanism model is established by using PipePhase software; step two, gathering and transportation process technical parameter input models are determined; step three, according to the calculation results, operating parameters affecting energy consumption are determined; step four, single well liquid production and gathering pipe radius are divided; step five, according to the calculation results, ton liquid gas consumption and ton oil gas consumption are calculated; step six, advanced value, average value and minimum value of ton liquid gas consumption and ton oil gas consumption are divided; step seven, the data obtained by calculation are summarized, and a station energy consumption system table is formulated; step eight, actual energy consumption tables of each station are collected, compared with the station energy consumption system table, and analyzed and on-site guidance optimization is carried out.A way for determining whether the energy consumption level is qualified and the operating parameters affecting the comprehensive energy consumption is provided.

Description

Technical Field

[0001] This invention relates to the field of oil and gas gathering and transportation systems in oilfield surface engineering, and in particular to an evaluation method for indicators of oilfield water-blending process gathering and transportation systems. Background Technology

[0002] In oilfield oil and gas production, 50% of the total energy consumption is concentrated in the gathering and transportation system. Numerous indicators and factors influence the energy consumption of this system, and many of these factors are interrelated. Current technologies lack accurate comprehensive energy consumption indicators as evaluation criteria for regulating and optimizing the comprehensive energy consumption of the gathering and transportation system. This makes it impossible to accurately determine whether the energy consumption levels of each station are up to standard, and it is also difficult to accurately identify the key operating parameters that affect the comprehensive energy consumption of the gathering and transportation system. Therefore, to address these shortcomings, a method for evaluating the indicators of the gathering and transportation system in oilfield water-blending processes is proposed. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] To address the shortcomings of existing technologies, this invention provides an evaluation method for the indicators of a water-blending process gathering and transportation system in oilfields. This method solves the problems in existing technologies, such as the lack of accurate comprehensive energy consumption indicators as evaluation criteria when regulating and optimizing the comprehensive energy consumption of the gathering and transportation system, the inability to accurately determine whether the energy consumption level of each station is qualified, and the inability to accurately determine the important operating parameters that affect the comprehensive energy consumption of the gathering and transportation system during operation.

[0005] (II) Technical Solution

[0006] To address the above problems, this invention provides a method for evaluating the performance of an oilfield water blending process gathering and transportation system, comprising:

[0007] Step 1: Input the relevant data of oil wells and pipelines into PipePhase software to build a mechanism model of the gathering and transportation system;

[0008] Step 2: Determine the technical parameters of the gathering and transportation process and input them into the established model;

[0009] Step 3: Based on the calculated results, determine the operating parameters that affect energy consumption;

[0010] Step 4: Determine the single-well production rate and oil gathering pipe radius;

[0011] Step 5: Based on the process modeling calculation results, calculate the gas consumption per ton of liquid and the gas consumption per ton of oil;

[0012] Step Six: Classify the advanced, average, and minimum values ​​of gas consumption per ton of liquid and gas consumption per ton of oil;

[0013] Step 7: Based on the data calculated in Steps 3 to 6, compile a station energy consumption system table;

[0014] Step 8: Collect the actual energy consumption tables of each station, compare them with the station energy consumption system tables obtained in Step 6, and analyze and provide on-site guidance for optimization based on the differences between the two.

[0015] Furthermore, the oil well and pipeline related data input in step one include wellhead pressure, wellhead temperature, daily oil production, water cut, gas-oil ratio, crude oil properties, pipeline length, pipe diameter, wall thickness, pipeline roughness, heat transfer coefficient, and starting and ending pressure and temperature.

[0016] Furthermore, the technical parameters of the gathering and transportation process in step two include wellhead back pressure, water injection outlet temperature at the oil transfer station, and water injection volume per well.

[0017] Furthermore, the operating parameters affecting energy consumption in step three are obtained by calculating and analyzing different parameter combinations through modeling in step one.

[0018] Furthermore, the division of production volume in step four is intended to cover 90% of oil wells and should not be too precise, but should be divided in units of 10t / d; the division of gathering and transportation radius should also not be too large, and should be taken as diameters of 300m, 500m, 1000m and 1500m respectively.

[0019] Furthermore, the method for calculating gas consumption per ton of liquid and gas consumption per ton of oil in step five is to use an energy-optimal calculation mathematical model.

[0020]

[0021] Calculate the gas consumption per ton of liquid and gas consumption per ton of oil under the corresponding production and gathering and transportation radius optimization.

[0022] Furthermore, in step seven, the oil collection system is divided into three stages: spring and autumn, summer and winter, and energy consumption system tables are established for each stage.

[0023] (III) Beneficial Effects

[0024] The present invention provides an evaluation method for oilfield water blending process gathering and transportation system indicators. This method utilizes PipePhase software to establish a mechanism model of the gathering and transportation system. By inputting actual station operating parameters and data, it identifies key operating parameters affecting energy consumption. The method divides the designated station into single-well production and gathering / transport radius ranges. The data is then substituted into an optimal energy consumption calculation mathematical model according to these ranges. The obtained data is divided into three stages based on annual ambient temperature changes. An energy consumption system table for the designated station is compiled and summarized. This table is compared with the actual energy consumption of the station to determine the energy consumption level at different stages and ranges. The comparison results guide on-site optimization. In actual tests, this method can significantly reduce production energy consumption, with an estimated saving of approximately 15% in gas consumption for the gathering and transportation system, achieving low-energy operation of the system. Attached Figure Description

[0025] Figure 1 This is an example diagram illustrating the relationship between the gathering and transportation radius and the gas consumption per ton of liquid per well under different single-well liquid production rates, as presented in the evaluation method for oilfield water blending process gathering and transportation system indicators of the present invention.

[0026] Figure 2 This is an example diagram illustrating the relationship between the gathering and transportation radius and the gas consumption per ton of oil per well under different single-well production rates in the oilfield water blending process gathering and transportation system index evaluation method of the present invention.

[0027] Figure 3 This is a schematic diagram of the mathematical model for calculating the optimal energy consumption of the oilfield water blending process gathering and transportation system index evaluation method of the present invention. Detailed Implementation

[0028] 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 embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] In the description of this invention, it is necessary to understand that the orientation or positional relationship indicated by terms such as "upper", "lower", "inner", "outer", "top", and "bottom" are based on the orientation or positional relationship shown in the accompanying drawings. The purpose is only to facilitate the description of this invention and to simplify the description. It is not intended to indicate or imply that the component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0030] like Figure 1-3 As shown, this invention provides a method for evaluating the indicators of an oilfield water blending process gathering and transportation system, specifically including:

[0031] Step 1: Input the relevant data of oil wells and pipelines into PipePhase software to build a mechanism model of the gathering and transportation system;

[0032] In this invention, the PipePhase software mentioned in step one can establish a mechanism model of the oil gathering and transportation system based on the oil gathering process and perform calculation and analysis. When establishing the model, it is necessary to determine the basic data to be input. The basic data mainly includes basic parameters, crude oil properties, natural conditions, technical parameters, etc. The data to be input is shown in Table 1.

[0033] Table 1 Required Input Data Table

[0034] node Enter data oil well Wellhead pressure, wellhead temperature, daily oil production, water cut, gas-oil ratio, crude oil properties pipeline Pipe length, pipe diameter, wall thickness, pipe roughness, heat transfer coefficient, and pressure and temperature at the starting and ending points.

[0035] Among them, basic parameters, crude oil properties, natural conditions and other related data can be obtained from the historical operating data of the target well and can be recorded according to the actual situation of the project construction. Technical parameters need to be determined according to the characteristics of the oil gathering process.

[0036] Step 2: Determine the technical parameters of the gathering and transportation process and input them into the established model;

[0037] In this invention, the oil gathering process technical parameters that need to be determined in step two include the maximum allowable wellhead back pressure of mechanically produced oil wells, the processing temperature of the oil transfer station, the water injection outlet temperature of the oil transfer station, and the water injection volume per well.

[0038] The maximum allowable wellhead back pressure of the mechanically produced oil well should be 1.0MPa~1.5MPa according to Article 1.6 of the "Design Regulations for Oil and Gas Gathering and Transportation in Oilfields" (GB 503504.1.6); the processing temperature of the oil transfer station should be the freezing point of crude oil, but in order to meet the needs of subsequent free water removal and wastewater treatment, the scheme should be optimized and determined according to the actual situation; the water injection volume of a single well needs to be calculated based on the single well production, oil gathering radius, wellhead oil temperature, endpoint temperature, oil gathering and water injection pipe diameter, etc.

[0039] Step 3: Based on the calculated results, determine the operating parameters that affect energy consumption;

[0040] like Figure 1 The image shows the calculation results of the gathering and transportation system mechanism model established using PipePhase software in steps one and two of this invention. Based on the computer results, the data to be determined in step two is calculated. The temperature of the produced fluid entering the station needs to consider the station's processing temperature requirements and the crude oil gathering and transportation requirements. Typically, the transfer station is the crude oil's pour point point. Subsequent adjustments can be made based on the optimization of dehydration and wastewater treatment. For example, Daqing Oilfield has specified and required the temperature of water-containing crude oil entering the dehydration station.

[0041] ① The temperature for removing free water from water-drive produced fluid should not exceed 35℃.

[0042] ② The temperature for removing free water from polymer flooding produced fluid should not exceed 40℃.

[0043] ③ The temperature for removing free water from the produced fluid of the ternary composite flooding should not be lower than 40℃.

[0044] Then, to determine the water injection temperature at the wellhead of the treatment station, it is necessary to first estimate the water injection temperature and substitute it into the model established in step one, and then perform repeated simulation calculations. The results are as follows: for high water cut (water cut ≥ 90%) produced fluid, a water injection temperature of 50-60℃ is more suitable. For low permeability oilfields, where the produced fluid water cut is relatively low, a water injection temperature of 65-70℃ is more suitable.

[0045] Next, the water injection rate for a single well is determined. This rate is closely related to the gathering and transportation radius, the production rate of a single well, the wellhead oil temperature, and the inlet temperature of the transfer station. During the calculation process, the water injection rate for a single well needs to be predicted, taking into account the same water injection temperature as that at the processing station. This prediction is then substituted into the model established in step one. The calculation results yield wellhead back pressure and inlet temperature, among other things. The input water injection rate for a single well is continuously changed and adjusted to control the wellhead back pressure of each well between 1.0 MPa and 1.5 MPa. The inlet temperature is the freezing point of the crude oil. If the inlet temperature does not meet the requirements during the calculation process, the water injection rate for a single well can be increased. In this case, the wellhead back pressure will rise. If the wellhead back pressure has already reached the maximum pressure requirement, the results can be adjusted by increasing the water injection temperature or increasing the diameter of the gathering and transportation pipe until the final wellhead back pressure and inlet temperature meet the requirements. The input water injection rate for a single well at this point is the value used in the establishment of this model.

[0046] Step 4: Determine the single-well production rate and oil gathering pipe radius;

[0047] In this invention, based on the actual production and construction situation, the production volume of each well (ring) and the length of the oil gathering pipeline under the jurisdiction of the oil transfer station need to be categorized. The production volume categorization aims to cover 90% of the oil wells, and the categorization should not be too detailed, otherwise the calculated gas consumption per ton of liquid and gas consumption per ton of oil will be too small. The categorization range of the gathering and transportation radius of the oil gathering pipeline should also not be too large, because a long gathering and transportation radius results in large heat and pressure losses and high energy consumption. When the gathering and transportation radius is too large, changing the amount of water added is not the optimal means of optimizing energy consumption, and the experiment and modeling become meaningless. In the embodiment provided by this method, the production volume of each well (t / d) is categorized into 10 t / d increments, and the gathering and transportation radius is categorized into four levels: 300m, 500m, 1000m, and 1500m. In actual operation, the categorization range can be adjusted according to the actual working conditions of the target station.

[0048] Step 5: Based on the process modeling calculation results, calculate the gas consumption per ton of liquid and the gas consumption per ton of oil;

[0049] Based on the calculation results of the process modeling and the division of single-well production (t / d) and gathering and transportation radius in step four, the gas consumption per ton of liquid and the gas consumption per ton of oil are calculated.

[0050] First, the heat dissipation of the oil gathering and transportation pipeline is calculated according to the formula. (1)

[0051] Calculate the heat dissipation of the oil pipeline, where:

[0052] q — Heat dissipation per meter of pipe length, W / m;

[0053] K — Overall heat transfer coefficient of the pipeline, W / (m²) 2 ·℃);

[0054] t a —Average oil temperature, °C; General ;

[0055] t0 — Ambient temperature around the pipeline, °C;

[0056] D – outer diameter of the pipeline, in meters (m).

[0057] Secondly, the heat load of the heating furnace is calculated according to the formula. (2)

[0058] Calculate the heat load of the heating furnace, where:

[0059] Q—Heat required for heating of circulating water volume (MW);

[0060] G—Flow rate of circulating water entering the heating furnace (m³) 3 / h);

[0061] C—Specific heat of water (kcal / ℃.kg);

[0062] T1—Temperature (°C) of oil entering and leaving the metering station (or oil collection room) -- Note: Calculated using the above-mentioned oil system software (pipephase);

[0063] T2—Water mixing outlet temperature (°C)—Note: Follow the specifications described in step three.

[0064] In the above formula, the calculated values ​​of the target station's heating furnace heat load and oil pipeline heat dissipation are substituted into the following energy-optimal calculation mathematical model.

[0065] (3)

[0066] Where: F(x) — Comprehensive energy consumption of the oil collection system (kJ / d);

[0067] F df —Electricity consumption (kJ / d);

[0068] F rl —Thermal energy consumption (kJ / d);

[0069] f w —Moisture content of the medium entering the heating furnace;

[0070] G L —Flow rate of medium entering the heating furnace (kg / d);

[0071] △T L —Flow rate of medium entering and exiting the heating furnace (°C);

[0072] Q r — Fuel calorific value (kJ / m³) 3 );

[0073] △P—Pressure difference between the medium entering and exiting the pump (MPa);

[0074] η—Pump efficiency.

[0075] like Figure 3 The diagram shows a flowchart of the optimal energy consumption calculation mathematical model. The results obtained from the optimal energy consumption calculation mathematical model are used to calculate the gas consumption for gathering and transportation, as shown in the formula.

[0076] Q 气量 (m) 3 / h)=Q / (Q H P η) (4)

[0077] In the formula, Q 气量 —Gas consumption for gathering and transportation (m³) 3 / h);

[0078] Q—Heat required for all heating (MW);

[0079] Q H P—low calorific value fuel (oil, gas) is 10000 kcal / (m³). 3 / h);

[0080] η—Heating furnace efficiency (around 80%)

[0081] The calculated gas consumption for gathering and transportation is substituted into formulas (5) and (6) respectively for calculation.

[0082] q 吨液耗气 =24×Q 气量 / L 液 (5)

[0083] In the formula, q 吨液耗气 —Gas consumption per ton of liquid (m³ / t)

[0084] L 液—Production volume (t / d);

[0085] Q 气量 —Gas consumption for gathering and transportation (m3 / h)

[0086] ;q 吨油耗气 =24×Q 气量 / L 油 (6)

[0087] In the formula, q 吨油耗气 —Gas consumption per ton of fuel (m³) 3 / t)

[0088] L 油 —Oil production (t / d);

[0089] Q 气量 —Gas consumption for gathering and transportation (m³) 3 / h);

[0090] Based on the simulation results of process modeling, an energy consumption index system table is compiled during the calculation process, giving the gas consumption per ton of liquid and gas consumption per ton of oil corresponding to different single well liquid production and oil gathering radius.

[0091] The calculated energy consumption table is compiled by summarizing the divided single-well liquid production and gathering and transportation radius, as well as the corresponding single-well liquid ton gas consumption and single-well oil ton gas consumption.

[0092] Table 2 Calculation of Energy Consumption

[0093]

[0094] like Figure 1 , 2 As shown, based on the summarized energy consumption table, graphs were drawn showing the relationship between the gathering and transportation radius and the gas consumption per ton of liquid and the gas consumption per ton of oil under different single-well production rates. According to the graphs, the gas consumption per ton of liquid and the gas consumption per ton of oil are evenly distributed according to this method, so this method is reasonable.

[0095] Step Six: Classify the advanced, average, and minimum values ​​of gas consumption per ton of liquid and gas consumption per ton of oil;

[0096] In this invention, considering the changes in ambient temperature throughout the year, the operation of the oil collection system is divided into three stages: spring and autumn, summer, and winter. Production units can use the system according to the different seasons.

[0097] Meanwhile, based on the on-site operation, under relatively ideal working conditions, by strictly controlling the station's energy consumption indicators, advanced values ​​for gas consumption per ton of liquid and gas consumption per ton of oil can be obtained. Then, based on the control level, these are the average and minimum values, respectively.

[0098] Among them, the average single well production at this station ;

[0099] ;

[0100] ;

[0101] Step 7: Based on the data calculated in Steps 3 to 6, compile a station energy consumption system table;

[0102] Taking the Changyuan water-drive station of Daqing Oilfield as an example, the resulting station energy consumption system tables are shown in Tables 3, 4, and 5.

[0103] Table 3 Energy Consumption System of Changyuan Water Drive Station, Daqing Oilfield (Spring and Autumn Seasons)

[0104]

[0105] Table 4 Energy Consumption System of Changyuan Water Drive Station, Daqing Oilfield (Summer)

[0106]

[0107] Table 5 Energy Consumption System of Changyuan Water Drive Station, Daqing Oilfield (Winter)

[0108]

[0109] Step 8: Collect the actual energy consumption tables of each station, compare them with the station energy consumption system tables obtained in Step 6, and analyze and provide on-site guidance for optimization based on the differences between the two.

[0110] To ensure the rationality of the indicator system, this invention selected seven oil transfer (water discharge) stations from Daqing Oilfield's No. 2, No. 4, No. 8 Oil Production Plants and Qingxin Oilfield for data fitting of the indicator system. Details of the fitting are shown in Tables 6 and 7.

[0111] Table 6. Fitting Results of Indicators for Water-Drive to Oil Station Conversion in Daqing Changyuan Old Oilfield

[0112]

[0113] Table 7. Fitting Results of Indicators for Oil Transfer Stations in the Outer Oilfields of Daqing

[0114]

[0115] Based on the fitting results, a clear comparison can be made between the actual data of these seven stations and the calculated data of the bookstores. As shown in Tables 6 and 7:

[0116] Most of these seven stations have good fit, especially the Xingbei West 2 Transfer Station and Xingbei 902 Transfer Station under the jurisdiction of the Fourth Oil Production Plant, which can reach the advanced level in the indicator system.

[0117] Stations that did not meet the requirements of the indicator system generally had higher gas consumption in winter, while their gas consumption in summer basically met the system's indicator requirements. This was because production management was difficult in winter due to lower temperatures, and the return oil temperature of water-blended stations and oil transfer stations was not strictly controlled. Based on the indicator system, refined management can be carried out to optimize operating parameters and further reduce energy consumption in gathering and transportation.

[0118] The present invention provides an evaluation method for the index of oilfield water blending process gathering and transportation system. This method utilizes PipePhase software to establish a mechanism model of the gathering and transportation system, inputs actual station operating parameters and data, compiles and summarizes the energy consumption system table for designated stations, and compares it with the actual energy consumption of the stations to determine the energy consumption level at different stages and ranges. Based on the comparison results, it guides on-site optimization. In actual tests, this method can significantly reduce production energy consumption, and is expected to save approximately 15% of the gas consumption of the gathering and transportation system, achieving low-energy operation of the system.

[0119] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for evaluating the performance of an oilfield water blending process gathering and transportation system, characterized in that, include: Step 1: Input the relevant data of oil wells and pipelines into PipePhase software to build a mechanism model of the gathering and transportation system; Step 2: Determine the technical parameters of the gathering and transportation process, and input them into the established model; Step 3: Based on the calculated results, determine the operating parameters that affect energy consumption; Step 4: Determine the single-well production rate and oil gathering pipe radius; Step 5: Based on the process modeling calculation results, calculate the gas consumption per ton of liquid and the gas consumption per ton of oil; The optimal mathematical model for calculating energy consumption per ton of liquid gas and per ton of oil gas is as follows: ； Wherein, fw—moisture content of the medium entering the heating furnace; GL—flow rate of the medium entering the heating furnace, in kg / d; △TL—temperature difference between the flow rates of the medium entering and exiting the heating furnace, in °C; Qr—calorific value of the fuel, in kJ / m³. 3 ; △P—Pressure difference between the medium entering and exiting the pump, in MPa; η—Pump efficiency; Step Six: Classify the advanced, average, and minimum values ​​of gas consumption per ton of liquid and gas consumption per ton of oil; Step 7: Based on the data calculated in Steps 3 to 6, compile a station energy consumption system table; Step 8: Collect the actual energy consumption tables of each station, compare them with the station energy consumption system tables obtained in Step 7, and analyze and provide on-site guidance for optimization based on the differences between the two.

2. The method for evaluating the indicators of an oilfield water blending process gathering and transportation system according to claim 1, characterized in that, The oil well and pipeline related data input in step one include wellhead pressure, wellhead temperature, daily oil production, water cut, gas-oil ratio, crude oil properties, pipeline length, pipe diameter, wall thickness, pipeline roughness, heat transfer coefficient, and starting and ending pressure and temperature.

3. The method for evaluating the indicators of an oilfield water blending process gathering and transportation system according to claim 1, characterized in that, The technical parameters of the gathering and transportation process in step two include wellhead back pressure, water injection temperature at the oil transfer station, and water injection volume per well.

4. The method for evaluating the indicators of an oilfield water blending process gathering and transportation system according to claim 1, characterized in that, In step three, the operating parameters affecting energy consumption are obtained by calculating and analyzing different parameter combinations through modeling in step one.

5. The method for evaluating the indicators of an oilfield water blending process gathering and transportation system according to claim 1, characterized in that, The production volume division in step four covers 90% of the oil wells, and is divided in units of 10t / d; the gathering and transportation radii are respectively taken as diameters of 300m, 500m, 1000m and 1500m.

6. The method for evaluating the indicators of an oilfield water blending process gathering and transportation system according to claim 1, characterized in that, In step five, the gas consumption for gathering and transportation is calculated based on the results obtained from the optimal energy consumption calculation mathematical model. Then, the gas consumption per ton of liquid and per ton of oil is calculated based on the gas consumption for gathering and transportation. The formula for the gas consumption for gathering and transportation is as follows: Q 气量 =Q / (Q H Pη), In the formula, Q 气量 —Gas consumption for gathering and transmission, in cubic meters. 3 / h; Q—All heat required for heating, in MW; Q H P—lowest calorific value of fuel, 10000 kcal / (m³) for oil and gas. 3 / h); η—Heating furnace efficiency, which is 80%; The formulas for gas consumption per ton of liquid and gas consumption per ton of oil are: q 吨液耗气 =24×Q 气量 / L 液 In the formula, q 吨液耗气 —Gas consumption per ton of liquid, in cubic meters 3 / t; L 液 —Production volume, in t / d; Q 气量 —Gas consumption for gathering and transmission, in cubic meters. 3 / h; q 吨油耗气 =24×Q 气量 / L 油 In the formula, q 吨油耗气 —Gas consumption per ton of oil, in m³ 3 / t; L 油 —Oil production, in t / d; Q 气量 —Gas consumption for gathering and transmission, in cubic meters. 3 / h.

7. The method for evaluating the indicators of an oilfield water blending process gathering and transportation system according to claim 1, characterized in that, In step seven, the oil collection system is divided into three stages: spring and autumn, summer and winter, and energy consumption tables are established for each stage.

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