Method for evaluating indexes of gathering and transportation system in oilfield watering process

Abstract

The invention relates to the technical field of oil and gas gathering and transportation of oil field surface engineering, in particular to an index evaluation method for an oil field watering process gathering and transportation system. The oil field water mixing flow gathering and transportation system index evaluation method comprises the following steps: 1, establishing a gathering and transportation system mechanism model by utilizing PipePhase software; 2, determining technical parameters of the gathering and transportation process to be input into the model; 3, according to a calculation result, determining operation parameters influencing energy consumption; 4, dividing the liquid production capacity of a single well and the radius of an oil collecting pipe; 5, gas consumption per ton of liquid and gas consumption per ton of oil are measured and calculated according to the calculation result; sixthly, the advanced value, the average value and the minimum value of the gas consumption per ton of liquid and the gas consumption per ton of oil are divided; 7, summarizing the data obtained by calculation, and formulating a station yard energy consumption system table; and step 8, collecting an actual energy consumption table of each station yard, performing benchmarking with a station yard energy consumption system table, and performing analysis and field guidance optimization. And a mode for judging whether the energy consumption level is qualified or not and judging the operation parameters influencing the comprehensive energy consumption is provided.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas gathering and transportation systems for oilfield surface engineering, and in particular to an index evaluation method for a gathering and transportation system for an oilfield water mixing process. Background Art

[0002] In the oil and gas production process of oil fields, 50% of the comprehensive energy consumption is concentrated in the gathering and transportation system, and there are many indicators and factors that affect the energy consumption of the gathering and transportation system, and many of these factors are interrelated. In the prior art, there is no accurate comprehensive energy consumption index as a criterion for regulating and optimizing the comprehensive energy consumption of the gathering and transportation system, and it is impossible to accurately determine whether the energy consumption level of each station is qualified, and it is also impossible to accurately determine the important operating parameters that affect the comprehensive energy consumption of the gathering and transportation system. Therefore, in view of the above shortcomings, a method for evaluating the index of the gathering and transportation system of the oilfield water mixing process is proposed. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] In view of the shortcomings of the prior art, the present invention provides an oilfield water injection process gathering and transportation system index evaluation method, which solves the problem in the prior art that there is no accurate comprehensive energy consumption index as a criterion for judging when regulating and optimizing the comprehensive energy consumption of the gathering and transportation system, and it is impossible to accurately judge whether the energy consumption level of each station is qualified, and it is also impossible to accurately judge the important operating parameters that affect the comprehensive energy consumption of the gathering and transportation system during work.

[0005] (II) Technical solution

[0006] In order to solve the above problems, the present invention provides an oilfield water mixing process gathering and transportation system index evaluation method, comprising:

[0007] Step 1: Input relevant data of oil wells and pipelines into PipePhase software to establish the 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: Determine the operating parameters that affect energy consumption based on the output calculation results;

[0010] Step 4: Divide the single well liquid production and oil gathering pipe radius;

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

[0012] Step 6: Divide the advanced value, average value and minimum value 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, formulate a station energy consumption system table;

[0014] Step 8: Collect the actual energy consumption table of each station, compare it with the station energy consumption system table obtained in step 6, and analyze and optimize on-site guidance based on the differences between the two.

[0015] Furthermore, the oil well and pipeline related data input in step 1 include wellhead pressure, wellhead temperature, daily oil production, water content, gas-oil ratio, crude oil properties, pipeline length, pipe diameter, wall thickness, pipeline roughness, heat transfer coefficient, starting and ending pressure and temperature.

[0016] Furthermore, the technical parameters of the gathering and transportation process in step 2 include wellhead back pressure, water injection outlet temperature of the oil transfer station and water injection volume of a single well.

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

[0018] Furthermore, the division of liquid production in step 4 is intended to cover 90% of the oil wells and should not be too fine, and should be divided in units of 10t / d; the division of gathering and transportation radius should not be too large, and the diameters are 300m, 500m, 1000m and 1500m respectively.

[0019] Furthermore, the method for calculating the gas consumption per ton of liquid and per ton of oil in step 5 is to use the optimal energy consumption calculation mathematical model as follows:

[0020]

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

[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 respectively.

[0023] (III) Beneficial effects

[0024] The oilfield water mixing process gathering and transportation system index evaluation method provided by the present invention uses PipePhase software to establish a gathering and transportation system mechanism model, inputs the working parameters and operation data of the actual station to determine the important operation parameters that affect energy consumption, divides the single well liquid production and gathering and transportation radius range of the designated station, substitutes the divided range into the energy consumption optimal calculation mathematical model for calculation, divides the obtained data into three stages according to the annual ambient temperature changes, organizes and summarizes the energy consumption system table of the designated station, compares the obtained system table with the actual energy consumption of the station to judge the energy consumption degree of the station in different stages and ranges, and guides the on-site optimization operation according to the comparison results. Under actual tests, production energy consumption can be greatly reduced, and it is expected to save about 15% of the gas consumption of the gathering and transportation system, and realize low-consumption operation of the gathering and transportation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The calculation results of the oilfield water mixing process gathering and transportation system index evaluation method of the present invention after applying PipePhase software modeling;

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

[0027] Figure 3 This is an example diagram of the relationship between the gathering and transportation radius and the gas consumption per ton of oil in a single well under different single well liquid production rates in the oilfield water mixing process gathering and transportation system index evaluation method of the present invention;

[0028] Figure 4 Schematic diagram of the energy consumption optimal calculation mathematical model of the oil field water mixing process gathering and transportation system index evaluation method of the present invention DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In the description of the present invention, it is necessary to understand that the orientations or positional relationships indicated by “upper”, “lower”, “inside”, “outside”, “top”, “bottom”, etc. are all based on the orientations or positional relationships shown in the accompanying drawings. The purpose is only to facilitate the description of the present invention and simplify the description. It does not indicate or imply that the referred parts must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0031] like Figure 1-4As shown, the present invention provides an oilfield water mixing process gathering and transportation system index evaluation method, which specifically includes:

[0032] Step 1: Input relevant data of oil wells and pipelines into PipePhase software to establish the mechanism model of the gathering and transportation system;

[0033] In the present invention, the PipePhase software described in step 1 can establish a gathering and transportation system mechanism model according to the oil gathering process and perform calculation and analysis. When establishing the model, it is necessary to determine the basic data that need to be input, wherein the basic data mainly includes basic parameters, crude oil properties, natural conditions, technical parameters, etc. The data that need to be input are shown in Table 1.

[0034] Table 1 Data table to be entered

[0035]

[0036] Among them, basic parameters, crude oil properties, natural conditions and other related data can be retrieved from the historical operation data of the target well and recorded according to the actual situation of the engineering construction. The technical parameters need to be determined according to the characteristics of the oil gathering process.

[0037] Step 2: Determine the technical parameters of the gathering and transportation process and input them into the established model;

[0038] In the present invention, the oil gathering process technical parameters that need to be determined in step 2 include the maximum allowable wellhead back pressure of the mechanical oil production well, the processing temperature of the oil transfer station, the water injection outlet temperature of the oil transfer station and the water injection amount of a single well.

[0039] Among them, the maximum allowable wellhead back pressure of the mechanical oil production well should be 1.0MPa~1.5MPa according to Article 4.1.6 of GB 503504 of the "Oil Field Oil and Gas Gathering and Transportation Design Regulations"; the treatment temperature of the oil transfer station should be the freezing point of crude oil, but in order to meet the subsequent needs of free water removal and sewage treatment, the scheme should be optimized and determined according to the actual situation; the water injection amount of a single well needs to be calculated based on the single well production, oil gathering radius, wellhead oil temperature, terminal temperature, oil gathering water injection pipe diameter and other conditions.

[0040] Step 3: Determine the operating parameters that affect energy consumption based on the output calculation results;

[0041] like Figure 1 As shown in FIG. 1 , the calculation results of the gathering and transportation system mechanism model established by the PipePhase software in step 1 and step 2 of the present invention are shown. The data to be determined in step 2 are calculated according to the computer results, wherein the temperature of the produced liquid entering the station needs to consider the station processing temperature requirements and the crude oil gathering and transportation requirements. Usually, the oil transfer station enters the station at the freezing point of the crude oil, which can be adjusted later according to the optimization of dehydration and sewage treatment. For example, Daqing Oilfield stipulates and requires the temperature of water-containing crude oil entering the dehydration station:

[0042] ① The free water removal temperature of water drive produced fluid should not be higher than 35℃.

[0043] ② The free water removal temperature of polymer flooding produced fluid should not be higher than 40℃.

[0044] ③ The free water removal temperature of ASP flooding produced fluid should not be lower than 40℃.

[0045] Then, to determine the water injection temperature at the wellhead of the processing station, it is necessary to first estimate the water injection temperature and substitute it into the model established in step 1, and perform repeated simulation calculations. The result is: for high water content (water content ≥ 90%) produced fluid, the water injection temperature is more suitable to be set at 50-60°C. For low permeability oil fields, the water content of the produced fluid is relatively low, and the water injection temperature is more suitable to be set at 65-70°C.

[0046] Next, the water injection amount of a single well is determined. The water injection amount of a single well is closely related to the gathering and transportation radius, the liquid production of a single well, the oil output temperature at the wellhead, and the inlet temperature of the oil transfer station. During the calculation process, the water injection amount of a single well is the same as the water injection temperature at the wellhead of the processing station, so it is necessary to predict the water injection amount of a single well, and then substitute it into the model established in step one. The calculation results obtain the wellhead back pressure and inlet temperature and other results. The input single well water injection amount is continuously changed and debugged to control the wellhead back pressure of each well between 1.0MPa and 1.5MPa. The inlet temperature is the solidification point of crude oil. During the calculation process, if the inlet temperature is not satisfied, the value of the single well water injection amount can be increased. At this time, the wellhead back pressure will rise. If the wellhead back pressure has reached the maximum pressure requirement, the result can be adjusted by increasing the water injection temperature or increasing the gathering and transportation pipe diameter until the wellhead back pressure and inlet temperature of the final result meet the requirements. At this time, the input single well water injection amount is the single well water injection amount value used in this model establishment.

[0047] Step 4: Divide the single well liquid production and oil gathering pipe radius;

[0048] In the present invention, it is necessary to divide the liquid production of a single well (ring) and the length of the oil gathering pipeline under the jurisdiction of the oil transfer station into grades according to the actual production and construction situation. The division of production is intended to cover 90% of the oil wells, and the division should not be too fine when dividing, otherwise the calculated gas consumption per ton of liquid and gas consumption per ton of oil will be too small. Among them, the division span of the gathering and transportation radius of the oil gathering pipeline should not be too large, because when the gathering and transportation radius is long, the thermal and pressure losses are large, and the gathering and transportation energy consumption is high. When the gathering and transportation radius is too high, changing the amount of water is not the best means to optimize energy consumption, and this experiment and modeling lose their meaning. In the embodiment provided by the present method, the division of the liquid production (t / d) of a single well is selected as one grade for every 10t / d, and the gathering and transportation radius is divided into four grades of 300m, 500m, 1000m and 1500m. In the actual working process, the division range can be adjusted according to the actual working conditions of the target station.

[0049] Step 5: Calculate the gas consumption per ton of liquid and per ton of oil based on the calculation results of process modeling;

[0050] Based on the calculation results of process modeling and the division of single well liquid production (t / d) and gathering and transportation radius in step 4, the gas consumption per ton of liquid and per ton of oil is calculated.

[0051] First, the heat dissipation of the oil gathering and transportation pipeline is calculated according to the formula

[0052] q=KπD(t a -t0) (1)

[0053] Calculate the heat dissipation of the oil pipeline, where:

[0054] q——heat dissipation per meter of tube length, W / m;

[0055] K——total heat transfer coefficient of pipeline, W / (m 2 ℃);

[0056] t a ——Average oil temperature, ℃; generally

[0057] t0——Ambient temperature around the pipeline, °C;

[0058] D——Pipeline outer diameter, m.

[0059] Secondly, calculate the heat load of the heating furnace according to the formula

[0060]

[0061] Calculate the heat load of the heating furnace, where:

[0062] Q—heat required for heating the circulating water content (MW);

[0063] G—Flow rate of circulating water into the heating furnace (m 3 / h);

[0064] C—specific heat of water (kcal / ℃.kg);

[0065] T1—Temperature of oil transfer station at metering station (or oil collection room) (℃)—Note: Calculated using the above oil system software (pipephase);

[0066] T2—Water blending outlet temperature (℃)--Note: Follow the specifications described in step three.

[0067] In the above formula, the calculated values ​​of the heating furnace heat load and the heat dissipation of the oil pipeline at the target station are substituted into the following mathematical model for the optimal calculation of energy consumption:

[0068]

[0069] Where: F(x)—comprehensive energy consumption of oil collection system (kJ / d);

[0070] F df —Electricity consumption (kJ / d);

[0071] F rl —thermal energy consumption (kJ / d);

[0072] f w —Moisture content of medium entering the heating furnace;

[0073] G L — Medium flow rate into the heating furnace (kg / d);

[0074] △T L — Medium flow rate in and out of the heating furnace (℃);

[0075] Q r —Fuel calorific value (kJ / m 3 );

[0076] △P—pressure difference between medium entering and leaving the pump (MPa);

[0077] η—Pump efficiency.

[0078] like Figure 4 As shown in the figure, it is a schematic diagram of the flow chart of the optimal energy consumption calculation mathematical model. The results of the optimal energy consumption calculation mathematical model are used to calculate the gas gathering and transportation consumption, as shown in the formula

[0079] Q 气量 (m 3 / h)=Q / (Q H Pη) (4)

[0080] In the formula, Q 气量—Gas consumption (m 3 / h);

[0081] Q—heat required for all heating (MW);

[0082] Q H P—fuel low calorific value oil, gas is 10000 kcal / (m 3 / h);

[0083] η—Heating furnace efficiency (about 80%)

[0084] Substitute the calculated gas gathering and transportation consumption into formula (5) and formula (6) to calculate

[0085] q 吨液耗气 =24×Q 气量 / L 液 (5)

[0086] In the formula, q 吨液耗气 —Gas consumption per ton of liquid (m 3 / t)

[0087] L 液 —Liquid production (t / d);

[0088] Q 气量 —Gas consumption (m 3 / h);

[0089] q 吨油耗气 =24×Q 气量 / L 油 (6)

[0090] In the formula, q 吨油耗气 — Gas consumption per ton of oil (m 3 / t)

[0091] L 油 —Oil production (t / d);

[0092] Q 气量 —Gas consumption (m 3 / h);

[0093] During the calculation process, an energy consumption index system table is compiled based on the results of process modeling simulation, giving the gas consumption per ton of liquid and per ton of oil for gathering and transportation corresponding to different single well liquid production and oil gathering radius.

[0094] The divided single well liquid production and gathering radius as well as the corresponding single well gas consumption per ton of liquid and single well gas consumption per ton of oil are summarized into the calculated energy consumption table shown in Table 2.

[0095] Table 2 Calculation of energy consumption

[0096]

[0097] like Figure 2 , 3 As shown in the figure, according to the summarized calculated energy consumption table, the relationship diagram between the gathering and transportation radius and the gas consumption per ton of liquid and the gas consumption per ton of oil of a single well is drawn under different single well liquid production. It can be seen from the figure that the intervals of gas consumption per ton of liquid and gas consumption per ton of oil divided by this method are evenly distributed, so this division method is reasonable.

[0098] Step 6: Divide the advanced value, average value and minimum value of gas consumption per ton of liquid and gas consumption per ton of oil;

[0099] In the present invention, in view of the changes in ambient temperature throughout the year, the operation of the oil collection system is divided into three stages, namely spring and autumn, summer and winter. Production units can use them separately according to different seasons.

[0100] At the same time, according to the on-site operating conditions, under relatively ideal working conditions, the station energy consumption indicators are strictly controlled, and the advanced values ​​of gas consumption per ton of liquid and gas consumption per ton of oil can be obtained, and then the average value and the minimum value are obtained according to the control level.

[0101] Among them, the total liquid production of the oil transfer station / the number of wells under the oil transfer station = the average liquid production of a single well in the station;

[0102] Total length of oil gathering pipelines of oil wells in oil transfer station / number of wells under the jurisdiction of oil transfer station = average length of oil gathering pipelines per well;

[0103] Gas consumption per ton of liquid (oil) × total liquid production of the station = calculated gas consumption of this station.

[0104] Step 7: Based on the data calculated in steps 3 to 6, formulate a station energy consumption system table;

[0105] Taking the Changyuan water drive station of Daqing Oilfield as an example, the energy consumption system tables of the station are shown in Tables 3, 4 and 5.

[0106] Table 3 Energy consumption system of Changyuan water drive station in Daqing Oilfield (spring and autumn seasons)

[0107]

[0108]

[0109] Table 4 Energy consumption system of Changyuan water drive station in Daqing Oilfield (summer)

[0110]

[0111] Table 5 Energy consumption system of Changyuan water drive station in Daqing Oilfield (winter)

[0112]

[0113] Step 8: Collect the actual energy consumption table of each station, compare it with the station energy consumption system table obtained in step 6, and analyze and optimize on-site guidance based on the differences between the two.

[0114] In order to ensure the rationality of the index system, the present invention selected 7 oil transfer (water release) stations including the Second Oil Production Plant, the Fourth Oil Production Plant, the Eighth Oil Production Plant and the Qingxin Oil Field in Daqing Oilfield to fit the index system data. The fitting results are shown in Tables 6 and 7.

[0115] Table 6. Index fitting of water drive to oil station in Daqing Changyuan old oilfield

[0116]

[0117]

[0118] Table 7 Daqing peripheral oilfield transfer station index fitting table

[0119]

[0120] According to the fitting results, we can clearly compare the actual data of the seven stations with the fitting results of the calculation book. According to Tables 6 and 7, we can know that:

[0121] Most of these seven stations have a good fit, especially the Xingbei West No. 2 Oil Transfer Station and Xingbei 902 Oil Transfer Station under the jurisdiction of Oil Production Plant No. 4, which can reach the advanced level in the index system.

[0122] The stations that fail to meet the requirements of the index system generally have higher gas consumption in winter and basically meet the gas consumption requirements of the system index in summer. The reason is that the temperature is lower in winter, production management is difficult, and the water blending outlet and oil return temperature of the oil transfer station are not strictly controlled. Based on the index system, refined management can be carried out, operating parameters can be optimized, and energy consumption in gathering and transportation can be further reduced.

[0123] The oilfield water mixing process gathering and transportation system index evaluation method provided by the present invention uses PipePhase software to establish a gathering and transportation system mechanism model, inputs the actual station working parameters and operation data, sorts and summarizes the energy consumption system table of the designated station, compares it with the actual energy consumption of the station to judge the energy consumption level of the station at different stages and ranges, and guides the on-site optimization operation according to the comparison results. Under actual tests, production energy consumption can be greatly reduced, and it is expected to save about 15% of the gas consumption of the gathering and transportation system, realizing low-consumption operation of the gathering and transportation system.

[0124] Finally, it should be noted that the above 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 aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for evaluating indicators of a gathering and transportation system for an oilfield water mixing process, characterized in that: include: Step 1: Input relevant data of oil wells and pipelines into PipePhase software to establish the 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: Determine the operating parameters that affect energy consumption based on the output calculation results; Step 4: Divide the single well liquid production and oil gathering pipe radius; Step 5: Calculate the gas consumption per ton of liquid and per ton of oil based on the calculation results of process modeling; Step 6: Divide the advanced value, average value and minimum value 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, formulate a station energy consumption system table; Step 8: Collect the actual energy consumption table of each station, compare it with the station energy consumption system table obtained in step 6, and analyze and optimize on-site guidance based on the differences between the two.

2. The oilfield water mixing process gathering and transportation system index evaluation method according to claim 1 is characterized in that: The oil well and pipeline related data input in step 1 include wellhead pressure, wellhead temperature, daily oil production, water content, gas-oil ratio, crude oil properties, pipeline length, pipe diameter, wall thickness, pipeline roughness, heat transfer coefficient, starting point and end point pressure and temperature.

3. The oilfield water mixing process gathering and transportation system index evaluation method according to claim 1 is characterized in that: The technical parameters of the gathering and transportation process in step 2 include wellhead back pressure, water injection outlet temperature of the oil transfer station and water injection volume of a single well.

4. The oilfield water mixing process gathering and transportation system index evaluation method according to claim 1 is characterized in that: The operating parameters that affect energy consumption in step three are obtained by calculating and analyzing different parameter combinations through the modeling in step one.

5. The oilfield water mixing process gathering and transportation system index evaluation method according to claim 1 is characterized in that: The division of liquid production in step 4 is intended to cover 90% of the oil wells, and should not be too fine, and should be divided in units of 10t / d; the division of gathering and transportation radius should not be too large, and the diameters are 300m, 500m, 1000m and 1500m respectively.

6. The oilfield water mixing process gathering and transportation system index evaluation method according to claim 1 is characterized in that: The method for calculating the gas consumption per ton of liquid and per ton of oil in step 5 is to use the optimal energy consumption calculation mathematical model as follows Calculate the gas consumption per ton of liquid and per ton of oil under the corresponding optimized production and gathering and transportation radius.

7. The oilfield water mixing process gathering and transportation system index evaluation method according to claim 1 is characterized in that: In the step 7, the oil collection system is divided into three stages: spring and autumn, summer and winter, and energy consumption system tables are established respectively.

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