CN110988149A - Method for extraction experiments - Google Patents
Method for extraction experiments Download PDFInfo
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- CN110988149A CN110988149A CN201911215678.0A CN201911215678A CN110988149A CN 110988149 A CN110988149 A CN 110988149A CN 201911215678 A CN201911215678 A CN 201911215678A CN 110988149 A CN110988149 A CN 110988149A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N5/00—Analysing materials by weighing, e.g. weighing small particles separated from a gas or liquid
- G01N5/04—Analysing materials by weighing, e.g. weighing small particles separated from a gas or liquid by removing a component, e.g. by evaporation, and weighing the remainder
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N2030/009—Extraction
Abstract
The embodiment of the invention provides a method for an extraction experiment, and belongs to the technical field of oil reservoir exploitation. The method comprises the following steps: placing a rock core of saturated oil liquid in a reaction kettle; injecting experimental gas into the reaction kettle to enable the gas pressure in the reaction kettle to reach the preset pressure of the current stage; adjusting the temperature in the reaction kettle to enable the temperature in the reaction kettle to reach the preset temperature of the current stage; detecting the weight of the core, and determining a first weight when the weight of the core stops changing, and the gas pressure and temperature in the reaction kettle at the preset temperature and the preset pressure of the current stage; and determining the volume of the oil mass extracted through the extraction experiment under different preset pressures and different preset temperatures according to the density of the oil, the initial weight of the rock core, the first weight, the gas density in the reaction kettle, the gas pressure and the temperature. The result of the volume of the extracted oil volume determined by the technical scheme has high accuracy.
Description
Technical Field
The invention relates to the technical field of oil reservoir exploitation, in particular to a method for extraction experiments.
Background
For the existing extraction experimental device for carrying out extraction experiments by using gas, experiments can be carried out only under a certain specific temperature and pressure, so that the density of the gas can be ensured to be constant, and data such as extraction recovery ratio and the like can be determined through a constant density value, so that extraction experiments under a group of temperature and pressure must be carried out firstly, then a rock core is taken out, and a next group of experiments are carried out after the extraction ratio is measured, so that the workload can be obviously increased through repeated operations, and the operation is complicated.
In addition, in the actual experiment process, parameters such as temperature and pressure in the experiment process are often changed due to various factors, especially the change of pressure, which has a great influence on the accuracy of the extraction experiment result.
Disclosure of Invention
It is an object of embodiments of the present invention to provide a method for extraction experiments that solves one or more of the above mentioned technical problems.
In order to achieve the above object, an embodiment of the present invention provides a method for extraction experiments, the method including: placing a rock core of saturated oil liquid in a reaction kettle; injecting experimental gas into the reaction kettle to enable the gas pressure in the reaction kettle to reach the preset pressure of the current stage; adjusting the temperature in the reaction kettle to enable the temperature in the reaction kettle to reach the preset temperature of the current stage; detecting the weight of the rock core, and determining a first weight when the weight of the rock core stops changing, and the gas pressure and temperature in the reaction kettle at the preset temperature and the preset pressure of the current stage; and determining the volume of the oil mass extracted through the extraction experiment under different preset pressures and different preset temperatures according to the density of the oil, the initial weight of the rock core, the first weight, the gas density in the reaction kettle, the gas pressure and the temperature.
Optionally, determining the volume of the extracted oil according to the density of the oil, the initial weight of the core, the first weight, the gas density in the reaction kettle, the gas pressure and the temperature includes: determining the density of the experimental gas in the reaction kettle when the weight of the rock core stops changing according to the type of the experimental gas, the gas pressure and the temperature in the reaction kettle; and determining the volume of the oil according to the density of the oil, the density of experimental gas in the reaction kettle when the weight of the rock core stops changing, the initial weight of the rock core and the weight when the weight of the rock core stops changing.
Optionally, determining the density of the test gas in the reaction vessel by the following formula:
where ρ isgnThe density of the experimental gas in the reaction kettle is shown, P shows the pressure of the experimental gas in the reaction kettle, M shows the molecular weight of the experimental gas, Z shows the compression factor of the experimental gas, R shows a universal gas constant, and T shows the temperature of the experimental gas in the reaction kettle.
Optionally, the volume of oil is determined by the following formula:
wherein, VonRepresents the volume of oil extracted, m0Denotes the initial weight of the core, mnRepresents the weight of the core at which the weight of the core stopped changing, ρoRepresents the oil density, ρgnThe density of the test gas in the reactor at which the core weight stopped changing is shown.
Optionally, the method further includes: when the weight of the rock core stops changing, determining that the extraction experiment at the current stage is finished; and after the extraction experiment at the current stage is completed, adjusting the gas pressure in the reaction kettle to reach the preset pressure at the next stage and/or adjusting the temperature in the reaction kettle to reach the preset temperature at the next stage, so as to perform the extraction experiment at the next stage.
Optionally, the method further includes: and determining the extraction degree of the rock core according to the oil volume and the crude oil volume of the saturated crude oil of the rock core.
Optionally, the core extraction production degree is determined by the following formula:
wherein k represents the extraction degree of the rock core, VonThe volume of oil extracted by the extraction experiment is shown, and V represents the crude oil volume of the saturated crude oil in the core.
Optionally, the method further includes: and continuously detecting the weight of the rock core through a weighing sensor arranged in the reaction kettle.
Optionally, the method further includes: the gas pressure in the reaction kettle is detected through a pressure sensor arranged in the reaction kettle.
Optionally, the method further includes: the temperature inside the reaction kettle is detected through a temperature sensor arranged inside the reaction kettle.
Through the technical scheme, the density of the experimental gas in the reaction kettle is determined according to the gas pressure and the temperature in the reaction kettle, and then the density is used for calculating the subsequent extraction oil quantity, so that the accuracy of the extraction experimental result can be improved.
Additional features and advantages of embodiments of the invention will be set forth in the detailed description which follows.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the embodiments of the invention without limiting the embodiments of the invention. In the drawings:
FIG. 1 is a flow chart of a method for extraction experiments provided by embodiments of the present invention.
Detailed Description
The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating embodiments of the invention, are given by way of illustration and explanation only, not limitation.
Fig. 1 is a flowchart of a method for extraction experiments according to an embodiment of the present invention, the method for extraction experiments including steps S110 to S150.
In step S110, a core of saturated oil is placed inside a reaction vessel.
Before an extraction experiment is carried out, oil saturation, aging and other treatment need to be carried out on a core, so that the core used in the experiment is similar to the state of a real oil reservoir as far as possible.
Specifically, the core is vacuumized and pressurized to saturate crude oil, and the saturated core is aged for a period of time and then placed into a reaction kettle.
In step S120, an experimental gas is injected into the reaction kettle so that the gas pressure in the reaction kettle reaches the preset pressure of the current stage.
The reaction kettle can be connected with a pressure control unit, and the pressure control unit can inject experimental gas with certain pressure into the reaction kettle.
Optionally, before the gas pressure inside the reaction kettle is adjusted, the reaction kettle can be purged by using the experimental gas, and the air inside the reaction kettle is discharged, so that the safety and reliability of the extraction experiment are improved.
Optionally, a pressure sensor may be further disposed inside the reaction kettle for detecting the pneumatic pressure inside the reaction kettle. In the process of adjusting the gas pressure inside the reaction kettle, the amount of the experimental gas injected into the reaction kettle by the pressure control unit can be adjusted according to the actually detected gas pressure inside the reaction kettle and the preset pressure.
In step S130, the temperature in the reaction kettle is adjusted to reach the preset temperature of the current stage.
The reation kettle can be provided with temperature control unit, temperature control unit can adjust reation kettle's temperature.
Optionally, the temperature control unit may be a heating pipe, the heating pipe may be arranged inside the reaction kettle to raise the temperature inside the reaction kettle, or the temperature control module may also be an incubator, and the temperature inside the reaction kettle is adjusted by placing the entire reaction kettle inside the incubator.
In step S140, the weight of the core is detected, and the first weight, the gas pressure inside the reaction vessel, and the temperature at which the weight of the core stops changing at the preset temperature and the preset pressure in the current stage are determined.
The weight of the core includes the initial weight of the core, and may also include the weight of the core during the extraction experiment.
When the core weight stops changing, it can be confirmed that the extraction experiment has been completed, and therefore the weight at which the core weight stops changing can be taken as the first weight.
Under the condition of low precision requirement on the extraction experiment, the preset temperature and the preset pressure of the extraction experiment can be directly used for subsequent calculation. If the requirement on the precision of the extraction experiment is high, the pressure in the reaction kettle when the weight of the rock core stops changing and the temperature in the reaction kettle when the weight of the rock core stops changing can be used for subsequent calculation. However, in the actual test process, when the weight of the core stops changing, the temperature and the gas pressure in the reaction kettle are basically consistent with the preset values.
In step S150, the volume of the oil extracted through the extraction experiment under different preset pressures and different preset temperatures is determined according to the density of the oil, the initial weight of the core, the first weight, the gas density in the reaction kettle, the gas pressure and the temperature.
Alternatively, the volume of oil extracted by the extraction experiment can be determined by the following equation:
wherein, VonRepresents the volume of oil extracted, m0Denotes the initial weight of the core, mnRepresenting the weight of the core at the time of weight change cessation，ρoRepresents the oil density, ρgnThe density of the test gas in the reactor at which the core weight stopped changing is shown.
Considering that the gas-tight density in the reaction kettle is different under different gas pressures and temperatures, and the different gas densities also affect the final determination of the extracted oil amount, the technical solution provided by this embodiment of the present invention needs to determine the extracted oil amount according to the gas pressure and temperature inside the reaction kettle.
Optionally, an embodiment of the present invention provides a method for determining a gas density, where the method determines, according to a type of a test gas, a gas pressure inside a reaction kettle, and a temperature, a gas density inside the reaction kettle when a core weight stops changing, and performs subsequent calculation by using the gas density.
Specifically, the density of the experimental gas inside the reaction vessel can be determined by the following formula:
where ρ isgnThe density of the experimental gas in the reaction kettle is shown, P shows the pressure of the experimental gas in the reaction kettle, M shows the molecular weight of the experimental gas, Z shows the compression factor of the experimental gas, R shows a universal gas constant, and T shows the temperature of the experimental gas in the reaction kettle.
The compression factor Z of the test gas can be determined by any conventional method, for example, by calculation, or by a gas compression factor chart according to data such as temperature and pressure of the test gas.
The technical scheme provided by the embodiment of the invention considers that the gas density in the reaction kettle is changed due to the fact that the gas pressure and the temperature in the reaction kettle are possibly fluctuated under the influence of various factors in the process of carrying out the extraction experiment, so that the technical scheme for determining the oil quantity extracted by the extraction experiment according to the actual gas density is provided, and the accuracy and the reliability of the experiment result can be improved.
Optionally, when the volume of the oil volume extracted by the extraction experiment is determined by the technical scheme provided by the embodiment of the invention, the extraction and extraction degree of the core can be determined according to the volume of the oil volume and the volume of the crude oil saturated by the core when the core is initially saturated with the crude oil.
Specifically, the core extraction production degree can be determined by the following formula:
wherein k represents the extraction degree of the rock core, VonThe volume of oil extracted by the extraction experiment is shown, and V represents the crude oil volume of the saturated crude oil in the core.
The embodiment of the invention also provides a method for extraction experiments, and because the gas density in the reaction kettle under different temperatures and pressures can be determined by the embodiment of the invention, a weighing sensor capable of continuously detecting the weight of the rock core can be arranged in the reaction kettle, and a plurality of groups of extraction experiments can be completed by using the same experimental equipment under the condition of not taking out the rock core.
Optionally, the method for extraction experiment provided by this embodiment of the present invention further includes: when the weight of the rock core stops changing, determining that the extraction experiment at the current stage is finished; and after the extraction experiment at the current stage is completed, adjusting the gas pressure in the reaction kettle to reach the preset pressure at the next stage and/or adjusting the temperature in the reaction kettle to reach the preset temperature at the next stage, so as to perform the extraction experiment at the next stage.
Specifically, after the extraction experiment at the current stage is determined to be completed, the volume of the oil amount extracted at the current stage can be determined according to the gas pressure and the temperature inside the reaction kettle when the weight of the core stops changing, then according to the experiment requirement, the gas pressure inside the reaction kettle and/or the temperature inside the reaction kettle is increased, after the adjustment is carried out to the preset pressure and/or the preset temperature value at the next stage, the adjustment is stopped, the extraction experiment at the next stage is carried out, when the weight of the core stops changing again, the extraction experiment at the stage is determined to be completed, in a manner similar to the above, the density of the gas inside the reaction kettle under the current condition is determined, and then the volume of the oil amount extracted at the stage is determined according to the density of the gas.
The technical scheme provided by the embodiment of the invention provides a method capable of continuously carrying out experiments, which can reduce the complicated steps of repeated operation and ensure the accuracy and reliability of experimental results.
Furthermore, when the extraction method provided by the embodiment is adopted to carry out continuous multi-group extraction experiments, the volume of oil extracted under different pressures and different temperatures can be analyzed and compared, and a reasonable basis is provided for actual exploitation and the like.
For example, in the course of extraction experiments, the initial weight of the core when the reaction kettle is filled with gas is recorded as m0According to the experimental requirements, extraction experiments under different temperature conditions and pressure regulation are carried out in stages, and the weight of the extracted rock core is recorded as m1、m2、m3……mnAnd the gas densities after the extraction experiments at different stages are respectively rhog1、ρg2、ρg3......ρgnThe weight data and the gas density data are in one-to-one correspondence, and in the subsequent calculation process, the data such as the oil extraction amount and the like under different experimental conditions can be calculated by adopting the corresponding weight and gas density.
Although the embodiments of the present invention have been described in detail with reference to the accompanying drawings, the embodiments of the present invention are not limited to the details of the above embodiments, and various simple modifications can be made to the technical solutions of the embodiments of the present invention within the technical idea of the embodiments of the present invention, and the simple modifications all belong to the protection scope of the embodiments of the present invention.
It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. In order to avoid unnecessary repetition, the embodiments of the present invention do not describe every possible combination.
Those skilled in the art will understand that all or part of the steps in the method according to the above embodiments may be implemented by a program, which is stored in a storage medium and includes several instructions to enable a single chip, a chip, or a processor (processor) to execute all or part of the steps in the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
In addition, any combination of various different implementation manners of the embodiments of the present invention is also possible, and the embodiments of the present invention should be considered as disclosed in the embodiments of the present invention as long as the combination does not depart from the spirit of the embodiments of the present invention.
Claims (10)
1. A method for extraction experiments, the method comprising:
placing a rock core of saturated oil liquid in a reaction kettle;
injecting experimental gas into the reaction kettle to enable the gas pressure in the reaction kettle to reach the preset pressure of the current stage;
adjusting the temperature in the reaction kettle to enable the temperature in the reaction kettle to reach the preset temperature of the current stage;
detecting the weight of the core, and determining a first weight when the weight of the core stops changing, and the gas pressure and temperature in the reaction kettle at the preset temperature and the preset pressure of the current stage; and
and determining the volume of the oil mass extracted through the extraction experiment under different preset pressures and different preset temperatures according to the density of the oil, the initial weight of the rock core, the first weight, the gas density in the reaction kettle, the gas pressure and the temperature.
2. The method of claim 1, wherein determining the volume of oil extracted according to the density of the oil, the initial weight of the core, the first weight, the density of gas in the reaction vessel, the gas pressure, and the temperature comprises:
determining the density of the experimental gas in the reaction kettle when the weight of the rock core stops changing according to the type of the experimental gas, the gas pressure and the temperature in the reaction kettle; and
and determining the volume of the oil according to the density of the oil, the density of experimental gas in the reaction kettle when the weight of the rock core stops changing, the initial weight of the rock core and the weight when the weight of the rock core stops changing.
3. The method of claim 2, wherein the density of the test gas within the reaction vessel is determined by the formula:
where ρ isgnThe density of the experimental gas in the reaction kettle is shown, P shows the pressure of the experimental gas in the reaction kettle, M shows the molecular weight of the experimental gas, Z shows the compression factor of the experimental gas, R shows a universal gas constant, and T shows the temperature of the experimental gas in the reaction kettle.
4. The method of claim 2, wherein the volume of oil is determined by the following equation:
wherein, VonRepresents the volume of oil extracted, m0Denotes the initial weight of the core, mnRepresents the weight of the core at which the weight of the core stopped changing, ρoRepresents the oil density, ρgnThe density of the test gas in the reactor at which the core weight stopped changing is shown.
5. The method of claim 1, further comprising:
when the weight of the rock core stops changing, determining that the extraction experiment at the current stage is finished; and
after the extraction experiment at the current stage is completed, adjusting the gas pressure in the reaction kettle to reach the preset pressure at the next stage and/or adjusting the temperature in the reaction kettle to reach the preset temperature at the next stage, so as to perform the extraction experiment at the next stage.
6. The method of claim 1, further comprising:
and determining the extraction degree of the rock core according to the oil volume and the crude oil volume of the saturated crude oil of the rock core.
7. The method of claim 6, wherein the degree of core extraction production is determined by the formula:
wherein k represents the extraction degree of the rock core, VonThe volume of oil extracted by the extraction experiment is shown, and V represents the crude oil volume of the saturated crude oil in the core.
8. The method of claim 1, further comprising:
and continuously detecting the weight of the rock core through a weighing sensor arranged in the reaction kettle.
9. The method of claim 1, further comprising:
the gas pressure in the reaction kettle is detected through a pressure sensor arranged in the reaction kettle.
10. The method of claim 1, further comprising:
the temperature inside the reaction kettle is detected through a temperature sensor arranged inside the reaction kettle.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911215678.0A CN110988149A (en) | 2019-12-02 | 2019-12-02 | Method for extraction experiments |
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| CN201911215678.0A CN110988149A (en) | 2019-12-02 | 2019-12-02 | Method for extraction experiments |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016061540A1 (en) * | 2014-10-17 | 2016-04-21 | All Clear Technologies, LLC | Radiation survey process |
| CN109374490A (en) * | 2018-08-27 | 2019-02-22 | 中国石油大学(北京) | Imbibition extraction equipment and imbibition extraction experiments method |
| CN110296926A (en) * | 2019-07-16 | 2019-10-01 | 长江大学 | A kind of densification oil rock heart imbibition experimental provision and its experimental method and its experimental system |
-
2019
- 2019-12-02 CN CN201911215678.0A patent/CN110988149A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016061540A1 (en) * | 2014-10-17 | 2016-04-21 | All Clear Technologies, LLC | Radiation survey process |
| CN109374490A (en) * | 2018-08-27 | 2019-02-22 | 中国石油大学(北京) | Imbibition extraction equipment and imbibition extraction experiments method |
| CN110296926A (en) * | 2019-07-16 | 2019-10-01 | 长江大学 | A kind of densification oil rock heart imbibition experimental provision and its experimental method and its experimental system |
Non-Patent Citations (3)
| Title |
|---|
| 任广明: "长垣外围特低渗透油藏CO2驱油室内实验及效果评价", 《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》 * |
| 崔传智 等: "水驱油藏中微观注水倍数计算方法", 《科学技术与工程》 * |
| 林云清: "注空气驱室内实验研究", 《当代化工》 * |
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