CN117887440A - CO suitable for shale oil development in micro-nano pores 2 Composite system - Google Patents
CO suitable for shale oil development in micro-nano pores 2 Composite system Download PDFInfo
- Publication number
- CN117887440A CN117887440A CN202410033634.0A CN202410033634A CN117887440A CN 117887440 A CN117887440 A CN 117887440A CN 202410033634 A CN202410033634 A CN 202410033634A CN 117887440 A CN117887440 A CN 117887440A
- Authority
- CN
- China
- Prior art keywords
- pressure
- oil
- composite system
- micro
- cosolvent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000002131 composite material Substances 0.000 title claims abstract description 180
- 239000003079 shale oil Substances 0.000 title claims abstract description 109
- 238000011161 development Methods 0.000 title claims abstract description 57
- 239000011148 porous material Substances 0.000 title claims abstract description 52
- 239000006184 cosolvent Substances 0.000 claims abstract description 126
- 238000000034 method Methods 0.000 claims abstract description 48
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 claims abstract description 24
- 238000000605 extraction Methods 0.000 claims description 75
- 238000002156 mixing Methods 0.000 claims description 23
- 238000004519 manufacturing process Methods 0.000 claims description 19
- 230000008569 process Effects 0.000 claims description 15
- 230000009467 reduction Effects 0.000 claims description 15
- 150000001875 compounds Chemical class 0.000 claims description 14
- 238000002347 injection Methods 0.000 claims description 12
- 239000007924 injection Substances 0.000 claims description 12
- 239000000203 mixture Substances 0.000 claims description 9
- 238000005259 measurement Methods 0.000 claims description 7
- 229920006395 saturated elastomer Polymers 0.000 claims description 7
- 239000011435 rock Substances 0.000 claims description 6
- UWFRVQVNYNPBEF-UHFFFAOYSA-N 1-(2,4-dimethylphenyl)propan-1-one Chemical compound CCC(=O)C1=CC=C(C)C=C1C UWFRVQVNYNPBEF-UHFFFAOYSA-N 0.000 claims description 3
- SBZXBUIDTXKZTM-UHFFFAOYSA-N diglyme Chemical compound COCCOCCOC SBZXBUIDTXKZTM-UHFFFAOYSA-N 0.000 claims description 3
- 238000011068 loading method Methods 0.000 claims description 3
- 238000002360 preparation method Methods 0.000 claims description 3
- 238000002791 soaking Methods 0.000 claims description 3
- YFNKIDBQEZZDLK-UHFFFAOYSA-N triglyme Chemical compound COCCOCCOCCOC YFNKIDBQEZZDLK-UHFFFAOYSA-N 0.000 claims description 3
- 230000015572 biosynthetic process Effects 0.000 abstract description 9
- 230000035699 permeability Effects 0.000 abstract description 6
- 239000003921 oil Substances 0.000 description 187
- LCGLNKUTAGEVQW-UHFFFAOYSA-N Dimethyl ether Chemical compound COC LCGLNKUTAGEVQW-UHFFFAOYSA-N 0.000 description 60
- 230000000694 effects Effects 0.000 description 37
- 239000010779 crude oil Substances 0.000 description 30
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 22
- 238000011084 recovery Methods 0.000 description 20
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 12
- 238000004090 dissolution Methods 0.000 description 11
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 10
- 239000002904 solvent Substances 0.000 description 10
- 230000000007 visual effect Effects 0.000 description 10
- 238000013461 design Methods 0.000 description 9
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 8
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 8
- 238000009792 diffusion process Methods 0.000 description 7
- 238000006073 displacement reaction Methods 0.000 description 7
- 230000003993 interaction Effects 0.000 description 7
- 239000007788 liquid Substances 0.000 description 7
- 239000010729 system oil Substances 0.000 description 7
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 6
- 238000005191 phase separation Methods 0.000 description 6
- 238000003860 storage Methods 0.000 description 6
- 230000009471 action Effects 0.000 description 5
- 230000001965 increasing effect Effects 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 230000002411 adverse Effects 0.000 description 4
- 230000000903 blocking effect Effects 0.000 description 4
- 238000013213 extrapolation Methods 0.000 description 4
- 238000012835 hanging drop method Methods 0.000 description 4
- DCAYPVUWAIABOU-UHFFFAOYSA-N hexadecane Chemical compound CCCCCCCCCCCCCCCC DCAYPVUWAIABOU-UHFFFAOYSA-N 0.000 description 4
- 229920000642 polymer Polymers 0.000 description 4
- 239000001294 propane Substances 0.000 description 4
- 230000008961 swelling Effects 0.000 description 4
- 230000002522 swelling effect Effects 0.000 description 4
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 230000002708 enhancing effect Effects 0.000 description 3
- 239000012752 auxiliary agent Substances 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 230000001788 irregular Effects 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229920003169 water-soluble polymer Polymers 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical group [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 241000218378 Magnolia Species 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000002671 adjuvant Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009530 blood pressure measurement Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 230000005465 channeling Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000009738 saturating Methods 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
- E21B43/164—Injecting CO2 or carbonated water
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/58—Compositions for enhanced recovery methods for obtaining hydrocarbons, i.e. for improving the mobility of the oil, e.g. displacing fluids
- C09K8/594—Compositions used in combination with injected gas, e.g. CO2 orcarbonated gas
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- Materials Engineering (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Geochemistry & Mineralogy (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
The invention discloses a CO suitable for shale oil development in micro-nano pores 2 The composite system consists of the following components in percentage by mass: 1.0 to 3.0 percent of cosolvent and the balance of CO 2 The method comprises the steps of carrying out a first treatment on the surface of the The cosolvent is nonionic cosolvent, including one or more of glycol dimethyl ether cosolvent. CO used in the present invention 2 The composite system can be applied to medium-low permeability oil reservoirs, is also suitable for low-pore low-permeability shale reservoirs with the permeability of generally 0.1mD-0.0001mD, particularly reservoirs rich in micro-nano pore structures, and can effectively avoid CO 2 The situation occurs where the composite system plugs the formation.
Description
Technical Field
The invention relates to the field of oil and gas field development, in particular to CO suitable for shale oil development in micro-nano pores 2 A composite system.
Background
In recent years, the exploration and development efforts of unconventional energy sources are gradually increased worldwide, shale oil is widely focused due to the huge reserves and development potential of the shale oil, but the shale reservoir is relatively high in heterogeneity and low in pore-density, so that the shale oil is relatively difficult to use. Indoor experiments and field practices show that CO 2 Development of shale oil compared with water drive, N 2 Flooding and the like have great advantages. Studies have shown that CO 2 The recovery ratio of mixed phase flooding is larger than that of non-mixed phase flooding, which means that more crude oil can be produced under the same condition. But shale reservoirs are strong in heterogeneity and high in micro-nano pore content, and CO is generated in the displacement process 2 The gas channeling is easy to occur along large gaps and pore channels, so that the oil in the micro-nano pores cannot be effectively used, and the displacement effect is poor. And CO 2 The throughput technology is divided into three processes of gas injection, well soaking and oil extraction, and CO can be better allowed in the well soaking process 2 Interact with crude oil. The pressure is gradually reduced in the oil extraction process, and when the pressure is lower than the miscible pressure, CO 2 Easy phase separation with crude oil, CO 2 And the crude oil may remain in the formation. Due to CO 2 High pressure of mixed phase with crude oil, and CO can be generated under higher pressure 2 Phase separation from crude oil affects the improvement in recovery. Meanwhile, due to high micro-nano pore content in shale, how to enhance CO 2 Interaction with shale oil in the micro-nano pores, thereby improving the utilization efficiency of the shale oil in the micro-nano pores and formingIs a key to influencing the efficient development of shale oil.
For conventional reservoir development technologies, the method aims at CO 2 Adding cosolvent to promote CO 2 Miscible with crude oil and CO reduction 2 Crude oil interfacial tension, etc., can be specifically designed and selected according to reservoir types, and the range of auxiliary solvent options is wide. For shale reservoirs with low pore size, low permeability and rich micro-nano pore structure, the severe stratum conditions lead to excellent construction performance of CO 2 Composite systems face challenges.
On one hand, the cosolvent with larger molecular weight and longer carbon chain length has the risk of blocking when being applied to shale reservoirs, and is adverse to CO after being added 2 Shale oil was developed. On the other hand, the cosolvent such as ethanol, butanol, acetone and the like commonly used at present is mixed with CO 2 Has limited affinity with CO 2 Co-injection into formation and CO-solvent from CO during huff and puff depressurization production 2 The amount of precipitated medium is large, and the application effect is greatly weakened. How CO-solvent is CO 2 Better miscibility with CO 2 Become a mixed system to increase CO 2 Polarity of (C) and thereby promote CO 2 Is contacted with crude oil to reach CO-philic 2 And lipophilic balance, maximally enhancing CO 2 There are few reports on the interaction with crude oil. Based on this, construction and CO 2 The cosolvent with higher affinity and the molecular weight as small as possible is suitable for shale micro-nano pore structure, and can be used for effectively reducing CO 2 -interfacial tension of oil, reduction of CO 2 Crude oil miscible pressure and CO elevation 2 Extraction/expansion performance of CO to oil 2 The composite system has great significance for efficiently developing shale oil.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and aims at a shale reservoir rich in a micro-nano pore structure, constructs CO suitable for efficient development of shale oil in the micro-nano pore 2 Composite system, the system being in CO 2 Can be used for reducing CO when shale oil is huff and puff developed 2 -interfacial tension of oil, reduction of CO 2 -oil miscible pressure and lifting CO 2 The extraction expansion effect, the stability is better, the compatibility is good, and the phase separation is not easy to occur under certain temperature and pressure.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
CO suitable for shale oil development in micro-nano pores 2 The composite system consists of the following components in percentage by mass: 1.0 to 3.0 percent of cosolvent and the balance of CO 2 ；
The cosolvent is a nonionic cosolvent and comprises one or more of ethylene glycol dimethyl ether cosolvents.
In one possible design, the co-solvent includes diethylene glycol dimethyl ether DDME, triethylene glycol dimethyl ether TEDM, and ethylene glycol diglycidyl ether TGDE.
In one possible design, the CO suitable for shale oil development in micro-nanopores 2 The composite system consists of the following components in percentage by mass: 3.0% cosolvent and the balance of CO 2 。
The invention also discloses a CO suitable for shale oil development in the micro-nano pores 2 The preparation method of the composite system comprises the following steps:
s1, measuring cosolvent and CO with a set mass ratio at a set temperature 2 Cloud point pressure of the mixture;
s2, mixing the cosolvent and CO according to the set mass ratio 2 The mixture is mixed under the pressure higher than the cloud point, thus obtaining CO suitable for the development of shale oil in micro-nano pores 2 A composite system.
In one possible design, the mixing above cloud point pressure includes mixing 4-5MPa above cloud point pressure.
The invention also discloses a method for developing the shale oil in the micro-nano pores by utilizing the CO 2 The method for huff-puff development of shale oil by a composite system comprises the following steps:
(a) Measurement of CO 2 Interfacial tension between the composite system and oil, and calculating to obtain CO 2 Minimum miscible pressure between the composite system and the oil;
(b) Loading the saturated oil of the experimental rock core into a rock core holder, and applying confining pressure;
(c) Injecting the CO suitable for shale oil development in micro-nano pores 2 The throughput process is carried out by the composite system;
(d) Repeating the step (c) for a plurality of rounds of throughput.
In one possible design, the throughput process in step (d) includes a gas injection stage, a soak stage, and a production stage;
in the production stage, when the pressure of the outlet end of the core holder is higher than that of the CO suitable for shale oil development in the micro-nano pores 2 At the mixed phase pressure of the composite system and the oil, the production is carried out at the pressure drop speed of 0.2 MPa/h; when the pressure of the outlet end of the core holder is lower than the CO suitable for shale oil development in the micro-nano pores 2 The composite system was produced at a pressure drop rate of 2MPa/h at the miscible pressure of the oil.
In one possible design, in the step (b), the applying the confining pressure includes adjusting a pressure of the oil saturated into the core after applying the confining pressure.
The invention also discloses a CO suitable for shale oil development in the micro-nano pores 2 The composite system reduces CO 2 -interfacial tension of oil, reduction of CO 2 -oil miscible pressure and lifting CO 2 The application of extraction expansion rate.
CO used in the present invention 2 Composite system by mixing CO 2 The water-soluble polymer is mixed with a cosolvent at a certain temperature and a certain pressure, and can be applied to reservoirs with high formation pressure and reservoirs with low formation pressure. CO 2 The pressure of the composite system is 8.0-10.0MPa when the composite system is fully mixed, taking shale reservoir as an example, the development depth is about 2000m at present, the formation pressure coefficient is calculated to be 0.01MPa/m, the formation pressure is about 20MPa, and the CO is below the formation pressure 2 The composite system can be fully mixed, so that the situation that stratum is broken or can not be fully mixed due to the fact that the mixing pressure is too high is avoided; CO injection 2 In the production process of shale oil huff and puff depressurization, the cloud point of the cosolventThe pressure is low, and the cosolvent and CO are 2 The mixing is more uniform, CO 2 The composite system does not generate phase separation phenomenon, the cosolvent is not easy to separate out, and the cosolvent can be combined with CO 2 The mixing is more uniform, thereby following CO in the process of throughput development and depressurization 2 Flows together. CO at the same time 2 The composite system can realize CO through the action of low miscible pressure and low interfacial tension with shale oil 2 The shale oil in the low-pore hypotonic reservoir structure is carried out in the depressurization production process through the strong extraction effect and the expansion effect by the miscible flooding, so that the shale oil recovery ratio is improved. The lower miscible pressure benefits from the CO-solvent of the glycol dimethyl ether employed in the present invention in CO 2 Has higher solubility and can be combined with CO under the condition of lower pressure 2 Realize miscibility, and compared with cosolvent such as ethanol, butanol, acetone and the like, the glycol dimethyl ether cosolvent and CO 2 The affinity is higher.
The glycol dimethyl ether cosolvent is liquid at normal temperature and pressure and is prepared by mixing with CO 2 The compound system is more stable, and is easier to diffuse into oil after contacting with the oil, thereby driving CO 2 Molecules diffuse into the oil, and ether molecules can be found in shale oil molecules and CO 2 The molecules play a role in reducing interaction energy, and the existence of the ether molecules can promote CO 2 Polarity of (C) to promote CO 2 Intermixing with shale oil, whereas existing CO 2 In a gaseous cosolvent compound system composed of dimethyl ether, methane, propane and the like, the gaseous cosolvent exists in CO more stably 2 In the gas phase, the light components in the crude oil can be inhibited from going to CO 2 Volatilize in the gas phase, attenuate CO 2 The extraction and extraction of light components of the crude oil can keep the viscosity of the crude oil from rising, and promote CO 2 The heavy components are not easy to accumulate in the crude oil production process, so that the viscosity of the crude oil is not excessively high. However, on one hand, shale oil is generally low in viscosity and strong in fluidity, shale oil mined on site is generally light oil, and volatilization of light components of the shale oil is inhibited, so that recovery efficiency is not improved; on the other hand, gaseous CO-solvents cannot promote CO 2 Polarity and oil extraction properties due to the gaseous stateCosolvent is more CO-friendly 2 Often, a large amount of additive is needed to make the amount of solvent in the oil to a certain extent to exert the function of cosolvent, and the gaseous cosolvent is generally used in CO 2 The mole percentage in the composite system is up to 25%, while the cosolvent of the invention is in CO 2 The mol percentage in the composite system is only 0.20-1%, and the dosage is greatly reduced; on the other hand, the gaseous cosolvent is dissolved into the oil through the action of the gaseous cosolvent and the crude oil, and the trace addition has little effect on the expansion effect of the crude oil, but inhibits the volatilization of light components in the crude oil, so that the extraction effect of the crude oil is weakened.
The beneficial effects of the invention are as follows:
(1) CO of the invention 2 The composite system is exemplified by the case of containing DDME cosolvent, CO 2 The mixed phase pressure of the composite system-oil is 12.84MPa, compared with CO 2 The oil miscible pressure is reduced by 4.40MPa by 17.24MPa, the interfacial tension is reduced by 41 percent, and CO is reduced 2 The extraction amount of the compound system to the oil is CO 2 The oil extraction amount was 3.19 times and the swelling amount was 1.13 times. CO 2 In the composite system, under the action of glycol dimethyl ether cosolvent, the CO is accelerated 2 Interaction with oil, CO 2 The diffusion amount and the dissolution amount into the oil are increased, so that the expansion effect and the extraction effect of the composite system on crude oil are promoted, and the interfacial tension and the miscible pressure of the composite system and the oil are greatly reduced.
(2) The invention relates to CO suitable for shale oil development in micro-nano pores 2 Method for huff and puff development of shale oil by using composite system, and according to the relation between outlet end pressure and mixed phase pressure of composite system and oil, CO is produced by adjusting gas release speed and production time in huff and puff process 2 The composite system better plays the roles of elastic development in miscible phase and expansion extraction in non-miscible phase, and is more suitable for development of shale oil in micro-nano holes.
(3) CO used in the present invention 2 The composite system can be applied to medium-low permeability oil reservoirs, is also suitable for low-pore low-permeability shale reservoirs (the permeability is generally 0.1mD-0.0001 mD), is especially suitable for reservoirs rich in micro-nano pore structures, and can effectively avoid CO 2 Composite system blocking groundThe case of layers occurs.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a graph of CO-solvent and CO for determination of set temperature and mass ratio 2 Schematic of the apparatus for cloud point pressure of the mixture;
FIG. 2 is CO 2 Schematic of a device for huff and puff development of shale oil by a composite system.
FIG. 3 is a graph of solubility of glycol dimethyl ether co-solvents with pressure at various temperatures, wherein (a) temperature is 40 ℃, (b) temperature is 50 ℃, (c) temperature is 60 ℃;
FIG. 4 shows the CO-solvent mass fraction of 3.0% for different COs 2 Shape photograph of oil drop in the composite system;
FIG. 5 shows the CO-solvent mass fraction of 3.0% for different COs 2 An interfacial tension graph between the composite system and oil;
FIG. 6 is CO at different gas-oil ratios 2 Extraction and expansion of oil, wherein (a) is CO at different oil-gas ratios 2 Extraction and expansion of oil, (b) CO at different oil-gas ratios 2 Extraction rate and expansion rate of oil;
FIG. 7 is a CO containing 1% DDME by mass 2 Oil extraction and expansion histogram of the composite system;
FIG. 8 is a CO containing 1% DDME by mass 2 Oil extraction rate and expansion rate histogram of the composite system;
wherein, 1, a high-pressure visual container, 2, a high-pressure intermediate container and 3.CO 2 High-pressure container, electronic balance, electromagnetic stirrer, first valve, first high-pressure plunger pump, first pressure gauge, sixth-pass valve, second pressure gauge, first vacuum pump, second valve, third pressure gauge and third pressure gauge ，14.CO 2 Gas cylinder, 15.CO 2 A booster pump, a first constant temperature box, a third valve and a CO storage valve, wherein the booster pump is 16, the third valve is 17, and the CO storage valve is 18 2 The system comprises a composite system intermediate container, 19, an oil storage intermediate container, 20, an oil-gas separation device, 21, a flowmeter, 22, a second vacuum pump, 23, a fourth pressure gauge, 24, a fifth pressure gauge, 25, a second constant temperature box, 26, a core holder, 27, a fourth valve, 28, a fifth valve, 29, a sixth valve, 30, a seventh valve, 31, an eighth valve, 32, a confining pressure pump and 33, a second high-pressure plunger pump; 34. a ninth valve; 35. and a third high-pressure plunger pump.
Specific embodiments of the present invention have been shown by way of the above drawings and will be described in more detail below. The drawings and the written description are not intended to limit the scope of the inventive concepts in any way, but rather to illustrate the inventive concepts to those skilled in the art by reference to the specific embodiments.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
CO suitable for shale oil development in micro-nano pores 2 The composite system consists of the following components in percentage by mass: 1.0 to 3.0 percent of cosolvent and the balance of CO 2 ；
The cosolvent is nonionic cosolvent, including one or more of dimethyl ether cosolvent.
In one possible design, the co-solvents include diethylene glycol dimethyl ether DDME, triethylene glycol dimethyl ether TEDM, and ethylene glycol diglycidyl ether TGDE.
It will be appreciated that the ether adjuvants used are of lower molecular weight, with a DDME molecular weight of 134.17, a TEDM molecular weight of 178.23, and a TGDE molecular weight of 222.28, much lower than conventional surfactant molecular weights, reducing CO 2 Composite system blocking micro-nano pore structureThe potential for shale reservoirs.
In one possible design, CO suitable for shale oil development in micro-nanopores 2 The composite system consists of the following components in percentage by mass: 3.0% cosolvent and the balance of CO 2 。
The invention also discloses a CO suitable for shale oil development in the micro-nano pores 2 The preparation method of the composite system comprises the following steps:
s1, measuring cosolvent and CO with a set mass ratio at a set temperature 2 Cloud point pressure of the mixture;
in the present invention, the cloud point pressure is evaluated by a cloud point pressure measuring device. FIG. 1 is a graph of CO-solvent and CO for determination of set temperature and mass ratio 2 Schematic of the apparatus for cloud point pressure of the mixture.
According to the illustration in fig. 1, a high-pressure visual container 1, CO 2 High-pressure container 3, second pressure gauge 10, first vacuum pump 11, CO 2 One end of the gas cylinder 14 and one end of the high-pressure intermediate container 2 are respectively connected with a six-way valve 9; six-way valve 9 and CO 2 CO is arranged between the gas cylinders 14 in sequence 2 A booster pump 15 and a second valve 12; six-way valve 9 and CO 2 The high-pressure container 3 is provided with a first pressure gauge 8 in front; CO 2 An electronic balance 4 is arranged below the high-pressure container 3; an electromagnetic stirrer 5 is arranged below the high-pressure visual container 1; the other end of the high-pressure intermediate container 2 is connected with a first high-pressure plunger pump 7, and a first valve 6 is arranged between the other end of the high-pressure intermediate container 2 and the first high-pressure plunger pump 7; high-pressure intermediate container 2, second pressure gauge 10, electronic balance 4, first pressure gauge 8, CO 2 The high-pressure vessel 3, the high-pressure visual vessel 1, and the electromagnetic stirrer 5 are provided in the first incubator 16.
In fig. 1, in an incubator 16 with a set temperature, the cosolvent with the above mass ratio is poured into a high-pressure visual container 1, and the high-pressure visual container 1 is connected with a first intermediate container 2 through a six-way valve 9, so that the volume of an experimental system is variable; closing the first valve 6 and the second valve 12, connecting the high-pressure visual container 1 and the high-pressure intermediate container 2 with the first vacuum pump 11 through the six-way valve 9, and vacuumizing the high-pressure visual container 1 and the high-pressure intermediate container 2; CO is processed by 2 The CO in the high-pressure container 3 in the mass ratio 2 Introducing into a high-pressure visual container 1; the high-pressure visual container 1 is provided with a magneton, and the cosolvent is accelerated to CO under the rotation of the electromagnetic stirrer 5 2 Dissolution in the water; CO-solvent and CO are pumped by a first high pressure plunger pump 7 2 Pressurizing the composite system, slowly releasing pressure, and judging that the cosolvent with the mass ratio is in CO at a set temperature by a cloud point pressure method 2 Cloud point pressure within.
S2, mixing the cosolvent and CO according to a set mass ratio 2 The mixture is mixed under the pressure higher than the cloud point, thus obtaining CO suitable for the development of shale oil in micro-nano pores 2 A composite system.
In one possible design, mixing above the cloud point pressure includes mixing 4-5MPa above the cloud point pressure.
Optionally, mixing at 4-5MPa above the cloud point pressure comprises mixing and stirring at 4-5MPa above the cloud point pressure for 6h under the action of a magnetic stirrer 5.
The invention also discloses a method for developing the shale oil in the micro-nano pores by utilizing the CO 2 The method for huff-puff development of shale oil by a composite system comprises the following steps:
(a) Measurement of CO 2 Interfacial tension between the composite system and oil, and calculating to obtain CO 2 Minimum miscible pressure between the composite system and the oil;
by the interfacial tension vanishing method, the measured interfacial tension is linearly extrapolated to obtain CO 2 Minimum miscible pressure between the composite system and the simulated oil.
(b) Loading the saturated oil of the experimental rock core into a rock core holder, and applying confining pressure;
the core sample was washed with methylene chloride and dried in an oven, and the core dry weight was weighed using a high precision electronic balance. And then placing the core into a high-pressure container, vacuumizing and saturating the oil, wiping the oil on the surface of the core, and weighing the wet weight of the core.
FIG. 2 is CO 2 Schematic of a device for huff and puff development of shale oil by a composite system. As shown in fig. 2, a second high pressure plunger pump 33 is connected to the inlet end of the core holder 26; core holder 26 and a second high pressureA sixth valve 29, a fourth pressure gauge 23, one end of a fifth valve 28, a second vacuum pump 22, a fourth valve 27 and CO storage are sequentially arranged between the plunger pumps 33 2 A composite intermediate container 18 and a third valve 17; the other end of the fifth valve 28 is connected with the oil-gas separation device 20 and the flowmeter 21 in sequence; the outlet end of the core holder 26 is sequentially connected with a fifth pressure gauge 24, an eighth valve 31, an oil storage intermediate container 19, a ninth valve 34 and a third high-pressure plunger pump 35; the confining pressure pump 32 is communicated with the confining pressure cavity of the core holder 26; a seventh valve 30 is arranged between the confining pressure pump 32 and the core holder 26; the core holder 26, the fourth pressure gauge 23, the fifth pressure gauge 24 and the sixth valve 29 are disposed within the second incubator 25.
In fig. 2, a core of saturated oil is placed in the core holder 26, the sixth valve 29 is opened, and the confining pressure of the core holder 26 is set by the confining pressure pump 32.
(c) CO injection suitable for shale oil development in micro-nano pores 2 The throughput process is carried out by the composite system;
(1) and (3) gas injection stage: the switch of the constant temperature box 25 is turned on, the experimental temperature is set, the fourth valve 27 is turned on, and CO is stored 2 CO in intermediate container 18 of the composite system 2 The composite system is injected into the inlet end pipeline of the core holder 26, the third valve 17 is opened, and the CO is set by the second high-pressure plunger pump 33 2 The injection pressure of the composite system was stabilized for 12h. An indication of the fourth pressure gauge 23 is recorded. Opening the sixth valve 29, CO 2 The composite system reaches the outlet end of the core holder 26 through the core, the gas injection process is finished when the number of the fifth pressure gauge 24 is the same as the number of the fourth pressure gauge 23, the number of the fourth pressure gauge 23 at the moment is recorded, and the CO is calculated according to a gas state equation 2 Amount of composite system injection.
(2) And (3) a well stewing stage: the third valve 29 is closed and the shut-in time is set to perform the shut-in process.
(3) The production stage comprises the following steps: when the number of the fourth pressure gauge 23 is higher than CO 2 The production is carried out at a pressure drop rate of 0.2MPa/h at the miscible pressure of the composite system and the oil, when the fourth pressure gauge 23 indicates a number falling below CO 2 After the miscible pressure of the composite system and the oil, the mixture is subjected to a pressure drop speed of 2MPa/hAnd (3) production. When the gauge 24 gauge drops to atmospheric pressure, the production phase ends. The volume of oil in the oil and gas separator 20 is recorded as an indication of the flow meter 21.
(d) Multiple rounds of throughput: repeating the step (c) to carry out the multi-round throughput process.
It can be understood that the production speed can be timely adjusted by comparing the real-time pressure value of the outlet end of the core holder with the miscible pressure value, the auxiliary agent function can be better played, and the purpose of improving the recovery ratio is achieved.
In one possible design, in step (b), applying the confining pressure includes adjusting the pressure of the oil saturated into the core after applying the confining pressure.
The core holder 26 is evacuated from both the inlet and outlet end lines using a second vacuum pump 22. Opening a seventh valve 31, sucking oil in the oil storage intermediate container 19 back into an outlet end pipeline of the core holder 27, regulating the saturation pressure of the oil by a third high-pressure plunger pump 35, and then closing the seventh valve 31;
the invention also discloses a CO suitable for shale oil development in the micro-nano pores 2 The composite system reduces CO 2 -interfacial tension of oil, reduction of CO 2 -oil miscible pressure and lifting CO 2 Use in extraction expansion.
The invention is illustrated below by means of specific examples. In order to facilitate the repeatability of the experiment, hexadecane is used as a simulated oil sample of shale oil in the embodiment, the cosolvent and hexadecane adopted in the embodiment are purchased from Shanghai Michelia Biochemical technology Co., ltd, and the purity grade of the product is chemical purity; CO used 2 Is produced by Qingdao Tianyuan chemical industry Co.Ltd and has the purity of 99.8 percent.
Example 1
The DDME cloud point pressure with the mass fraction of 1.0 percent is 8.20MPa at 40 ℃ according to the determination method of the cloud point pressure; at 50 ℃, the cloud point pressure of the DDME with the mass fraction of 1.0 percent is 9.20MPa; at 60 ℃, the DDME cloud point pressure with the mass fraction of 1.0 percent is 9.30MPa, which is far lower than that of the CO in the oilfield site 2 To account for the CO-solvent and CO 2 Is relatively high in affinityStrong and can be carried with CO at a pressure higher than the cloud point pressure 2 And injected together to be used for shale oil displacement.
Measurement of CO using hanging drop method 2 Interfacial tension between the composite system and the simulated oil. DDME cosolvent with mass fraction of 1.0% for CO 2 Mixing to form CO 2 The cloud point pressure of the composite system is 9.20MPa at 50 ℃, and the CO is generated when the pressure is 10-13MPa 2 The interfacial tension between the complex system and the simulated oil is 0.45-2.25mN/m, and CO 2 The interfacial tension with the simulated oil is 0.57-2.53mN/m under the same pressure, and when the pressure is 14MPa, the simulated oil is in CO 2 The compound system can not be converged into liquid drops, which indicates that CO 2 The interfacial tension between the composite system and the simulated oil is already low. When the pressure is 10-13MPa, the amplitude of the interfacial tension is reduced to 11.06-21.05%, and the mass fraction is lower, but the effect is remarkable and is far higher than that of cosolvent such as ethanol, propanol, acetone and the like under the same mass fraction. Taking low molecular weight gaseous cosolvent dimethyl ether as an example, compared with dimethyl ether and CO with the same mass fraction 2 Mixing into CO 2 Composite system, the CO when the pressure is 10-13MPa 2 The interfacial tension between the compound system and the simulated oil is 0.53-2.50mN/m, and the interfacial tension is equal to that of pure CO 2 The system is not quite different. From this, it can be seen that the CO in the present invention 2 DDME in the composite system can be used in shale oil molecules and CO 2 The molecules play a role in reducing interaction energy, promote mutual diffusion of the molecules and the molecules to reduce interfacial tension, and dimethyl ether cannot strengthen CO 2 Polarity of (C) is increased 2 Is a performance of the (c).
By an interfacial tension vanishing method, the measured interfacial tension is linearly extrapolated, and CO is calculated 2 Minimum miscible pressure between the composite system and the simulated oil. The fitting formula is IFT= -0.328+4.742 (unit: mN/m), and when IFT is zero, the CO is calculated 2 The minimum miscible pressure between the composite system and the simulated oil is 14.45MPa; and CO 2 The minimum miscible pressure with the simulated oil was calculated to be 17.24MPa, the CO 2 The minimum miscible pressure of the composite system and the simulated oil is reduced by 2.79MPa, and the amplitude is reduced by 16.18 percentThe effect of reducing the amplitude is far higher than that of common cosolvent such as ethanol, propanol and the like under the same mass fraction. And dimethyl ether and CO with the same mass fraction 2 Mixed into CO 2 Composite system, the minimum miscible pressure between the composite system and simulated oil is calculated to be 17.12MPa by using IFT extrapolation method, and the minimum miscible pressure is calculated to be 17.12MPa with pure CO 2 The system is not quite different.
Calculation of CO at different pressures using the method disclosed in patent CN115524472A 2 The composite system was used to simulate oil extraction. The mass fraction of the DDME cosolvent is 1.0%, the simulated oil extraction rate reaches 90.2% under the pressure of 12.5MPa, the DDME cosolvent is not added, and under the same pressure, CO is added 2 The extraction rate of the simulated oil is only 30.55%, and the extraction effect is improved by nearly 2 times. Dimethyl ether and CO with the same mass fraction 2 Mixed into CO 2 The compound system has simulated oil extraction rate up to 29.84% under the pressure of 12.5MPa, and the addition of dimethyl ether adversely affects the CO 2 The system simulates the extraction effect of oil. Description of the CO of the invention 2 DDME in a composite system can be enhanced by CO 2 Polarity of (c) and promote CO 2 Mutual contact with oil, enhancing CO 2 The extraction of the oil, while the addition of the dimethyl ether can inhibit the volatilization of light components of the oil, which is unfavorable for CO 2 Extraction of oil.
Calculation of CO at different pressures using the method disclosed in patent CN115524472A 2 The composite system simulates the oil swell. The addition of the DDME cosolvent with the mass fraction of 1.0 percent improves the expansion coefficient of the simulated oil to 1.44 under the pressure of 12.5MPa, and the addition of the DDME cosolvent is not added, and the CO is carried out under the same pressure 2 The expansion coefficient of the simulated oil was 1.35, and overall the addition of DDME promoted CO 2 The composite system has an expansion effect on simulated oil, so that the shale oil recovery ratio is improved. Dimethyl ether and CO with the same mass fraction 2 Mixed into CO 2 The expansion coefficient of the compound system to the simulated oil is 1.32 when the pressure is 12.5MPa, and the addition of the dimethyl ether adversely affects the CO 2 The system simulates the swelling effect of oil. Description of CO in the present invention 2 DDME in a composite system can be enhanced by CO 2 Polarity of (c) and promote CO 2 Diffusion into oil promotes CO 2 Dissolution into oil, enhancing CO 2 Swelling of oil, whereas dimethyl ether is mainly caused to swell by a large amount of dissolved into the oil, but CO 2 The amount of the catalyst is far larger than that of the auxiliary agent, and the expansion effect of the dimethyl ether is limited, but the CO 2 The reduction of the duty cycle reduces the diffusion into the oil, so that it is disadvantageous for CO 2 Swelling action on oil.
Through five rounds of throughput, the CO 2 Shale oil is developed through the composite system, and the core recovery rate is 40.2%. Pure CO 2 Shale oil is developed through huff and puff, the core recovery ratio is 28.6%, and the CO is as follows 2 The recovery ratio of the composite system is improved to 11.6%. Therefore, trace DDME and CO 2 Constituted CO 2 The composite system can effectively reduce interfacial tension and miscible pressure with oil, and promote extraction and expansion of oil, thereby improving crude oil recovery efficiency.
Example 2:
shale reservoir with micro-nano pore structure, shale oil displacement can be used for reducing CO 2 -interfacial tension of oil, reduction of CO 2 -oil miscible pressure and lifting CO 2 Extraction of expanding CO 2 The composite system consists of the following components in percentage by mass: DDME 3.0%, CO 2 97.0％。
According to the method for measuring the cloud point pressure, the DDME cloud point pressure with the mass fraction of 3.0% is 8.40MPa at 40 ℃; at 50 ℃, the cloud point pressure of the DDME with the mass fraction of 3.0 percent is 9.88MPa; at 60 ℃, the cloud point pressure of the DDME with the mass fraction of 3.0 percent is 10.14MPa.
Measurement of CO using hanging drop method 2 Interfacial tension between the composite system and the simulated oil. 3.0% DDME cosolvent for CO 2 Mixing to form CO 2 The cloud point pressure of the composite system is 9.88MPa at 50 ℃, and the CO is generated when the pressure is 10-12MPa 2 The interfacial tension between the complex system and the simulated oil is 0.67-1.62mN/m, and CO 2 The interfacial tension with the simulated oil is 0.89-2.53mN/m under the same pressure, when the pressure is 1At 3MPa, the simulated oil is at CO 2 The compound system can not be converged into liquid drops, which indicates that CO 2 The interfacial tension between the composite system and the simulated oil is already low. When the pressure is 10-12MPa, the amplitude of the interfacial tension is reduced between 33.99-41.57%. Dimethyl ether and CO with the same mass fraction 2 Mixed into CO 2 Composite system, the CO when the pressure is 10-12MPa 2 The interfacial tension between the compound system and the simulated oil is 0.77-2.30mN/m, and the reduction effect is very limited.
By an interfacial tension vanishing method, the measured interfacial tension is linearly extrapolated, and CO is calculated 2 Minimum miscible pressure between the composite system and the simulated oil. The fitting formula is IFT= -0.577+7.414 (unit: mN/m), and when IFT is zero, the CO is calculated 2 The minimum miscible pressure between the composite system and the simulated oil is 12.84MPa; and CO 2 The minimum miscible pressure with the simulated oil was calculated to be 17.24MPa, the CO 2 The minimum miscible pressure of the composite system and the simulated oil is reduced by 4.40MPa, and the amplitude reduction reaches 25.52%. Dimethyl ether and CO with the same mass fraction 2 Mixed into CO 2 Composite system, the minimum miscible pressure between the composite system and simulated oil is calculated to be 17.02MPa by using IFT extrapolation method, and the minimum miscible pressure is calculated to be 17.02MPa with pure CO 2 The system is not quite different.
The method of example 1 was used to calculate CO at different pressures 2 The composite system was used to simulate oil extraction. The mass fraction of the DDME cosolvent is 3.0%, the simulated oil extraction rate reaches 97.6% under the pressure of 12.5MPa, the DDME cosolvent is not added, and under the same pressure, CO is added 2 The extraction rate of the simulated oil reaches 30.55%, and the extraction effect is 3.19 times of that of the simulated oil without adding the DDME cosolvent. Dimethyl ether and CO with the same mass fraction 2 Mixed into CO 2 The extraction rate of the compound system to the simulated oil is only 28.74% when the pressure is 12.5 MPa.
The method of example 1 was used to calculate CO at different pressures 2 The composite system simulates the oil swell. The addition of 3.0% of DDME cosolvent by mass fraction, when the pressure is 12.5MPa, the expansion coefficient of the simulated oil reaches 1.53, and the DDME cosolvent is not added, and the same is true CO under equal pressure 2 The overall expansion coefficient for the simulated oil was 1.35, with an expansion effect of 1.13 times that of the non-added DDME co-solvent. Dimethyl ether and CO with the same mass fraction 2 Mixed into CO 2 The coefficient of expansion of the composite system for simulated oil at a pressure of 12.5MPa is only 1.31.
Through five rounds of throughput, the CO 2 Shale oil is developed through the composite system, and the core recovery rate is 48.6%. And pure CO 2 Shale oil is developed through huff and puff, the core recovery ratio is 28.6%, and the CO is as follows 2 The recovery ratio of the composite system is improved to 20.0%.
Example 3:
shale reservoir with micro-nano pore structure, shale oil displacement can be used for reducing CO 2 -interfacial tension of oil, reduction of CO 2 -oil miscible pressure and lifting CO 2 Extraction of expanding CO 2 The composite system consists of the following components in percentage by mass: TEDM 3.0%, CO 2 97.0％。
According to the cloud point pressure measurement method, the TEDM cloud point pressure with the mass fraction of 3.0% is 8.50MPa at 40 ℃; at 50 ℃, the TEDM cloud point pressure with the mass fraction of 3.0 percent is 10.16MPa; at 60 ℃, the TEDM cloud point pressure with the mass fraction of 3.0 percent is 11.78MPa, which is far lower than the CO of the oilfield site 2 Is used for the injection pressure of the gas.
Measurement of CO using hanging drop method 2 Interfacial tension between the composite system and the simulated oil. TEDM cosolvent with mass fraction of 3.0% for CO 2 Mixing to form CO 2 The cloud point pressure of the composite system is 10.16MPa at 50 ℃, and the CO is generated when the pressure is 10-13MPa 2 The interfacial tension between the complex system and the simulated oil is 0.41-1.88mN/m, and CO 2 The interfacial tension with the simulated oil is 0.89-2.53mN/m under the same pressure, and when the pressure is 14MPa, the simulated oil is in CO 2 The compound system can not be converged into liquid drops, which indicates that CO 2 The interfacial tension between the composite system and the simulated oil is already low. When the pressure is 10-13MPa, the amplitude of the interfacial tension is reduced between 25.69-53.93%. Dimethyl ether and CO with the same mass fraction 2 MixingCO produced 2 Composite system, the CO when the pressure is 10-12MPa 2 The interfacial tension between the composite system and the simulated oil is 0.77-2.30mN/m.
By an interfacial tension vanishing method, the measured interfacial tension is linearly extrapolated, and CO is calculated 2 Minimum miscible pressure between the composite system and the simulated oil. The fitting formula is IFT= -0.330+4.680 (unit: mN/m), and when IFT is zero, the CO is calculated 2 The minimum miscible pressure between the composite system and the simulated oil is 14.18MPa; and CO 2 The minimum miscible pressure with the simulated oil was calculated to be 17.24MPa, the CO 2 The minimum miscible pressure of the composite system and the simulated oil is reduced by 3.06MPa, the amplitude reduction reaches 17.75%, and the dimethyl ether and CO with the same mass fraction are reduced 2 Mixed into CO 2 Composite system, the minimum miscible pressure between the composite system and simulated oil is calculated to be 17.02MPa by using IFT extrapolation method, and the minimum miscible pressure is calculated to be 17.02MPa with pure CO 2 The system is not quite different.
The method of example 1 was used to calculate CO at different pressures 2 The composite system was used to simulate oil extraction. The addition of the TEDM cosolvent with the mass fraction of 3.0 percent ensures that the simulated oil extraction rate reaches 94.8 percent under the pressure of 12.5MPa, and the CO under the same pressure without the addition of the TEDM cosolvent 2 The extraction rate of the simulated oil is only 30.55%, and the extraction effect is 3.10 times of that of the simulated oil without adding the TEDM cosolvent. Dimethyl ether and CO with the same mass fraction 2 Mixed into CO 2 The composite system has only 28.74% of simulated oil extraction rate under the pressure of 12.5 MPa.
The method of example 1 was used to calculate CO at different pressures 2 The composite system simulates the oil swell. The addition of the TEDM cosolvent with the mass fraction of 3.0 percent can lead the expansion coefficient of the simulated oil to reach 1.48 under the pressure of 12.5MPa, and the CO under the same pressure without the addition of the TEDM cosolvent 2 The overall expansion coefficient for the simulated oil was 1.35, with an expansion effect of 1.09 times that of the non-ted TEDM co-solvent. Dimethyl ether and CO with the same mass fraction 2 Mixed into CO 2 The expansion coefficient of the composite system for the simulated oil is only 1.31 at a pressure of 12.5 MPa.
Through five rounds of throughput, the CO 2 Shale oil is developed through the composite system, and the core recovery rate is 45.3%. And pure CO 2 Shale oil is developed through huff and puff, the core recovery ratio is 28.6%, and the CO is as follows 2 The recovery ratio of the composite system is improved to 16.7 percent.
Example 4:
shale reservoir with micro-nano pore structure, shale oil displacement can be used for reducing CO 2 -interfacial tension of oil, reduction of CO 2 -oil miscible pressure and lifting CO 2 Extraction of expanding CO 2 The composite system consists of the following components in percentage by mass: TGDE 3.0%, CO 2 97.0％。
According to the method for measuring the cloud point pressure, the TGDE cloud point pressure with the mass fraction of 3.0% is 8.67MPa at 40 ℃; at 50 ℃, the mass fraction is 3.0% and the TGDE cloud point pressure is 10.67MPa; at 60 ℃, the mass fraction of TGDE cloud point pressure of 3.0% is 12.46MPa.
Measurement of CO using hanging drop method 2 Interfacial tension between the composite system and the simulated oil. 3.0% by mass of TGDE CO-solvent for CO 2 Mixing to form CO 2 The cloud point pressure of the composite system is 10.67MPa at 50 ℃, and CO is generated when the pressure is 10-13MPa 2 The interfacial tension between the complex system and the simulated oil is 0.48-2.29mN/m, and CO 2 The interfacial tension with the simulated oil is 0.89-2.53mN/m under the same pressure, and when the pressure is 14MPa, the simulated oil is in CO 2 The converged droplets in the composite system are very small, which indicates that CO 2 The interfacial tension between the composite system and the simulated oil is already low. When the pressure is 10-13MPa, the amplitude of the interfacial tension is reduced between 9.48-46.07%. Dimethyl ether and CO with the same mass fraction 2 Mixed into CO 2 Composite system, the CO when the pressure is 10-12MPa 2 The interfacial tension between the composite system and the simulated oil is 0.77-2.30mN/m.
By an interfacial tension vanishing method, the measured interfacial tension is linearly extrapolated, and CO is calculated 2 Minimum miscible pressure between the composite system and the simulated oil. The fitting formula is IFT= -0.230+3.530%Units: mN/m), when IFT is zero, calculate the CO 2 The minimum miscible pressure between the composite system and the simulated oil is 15.34MPa; and CO 2 The minimum miscible pressure with the simulated oil was calculated to be 17.24MPa, the CO 2 The minimum miscible pressure of the composite system and the simulated oil is reduced by 1.90MPa, and the amplitude reduction reaches 11.02%. Dimethyl ether and CO with the same mass fraction 2 Mixing into CO 2 Composite system, the minimum miscible pressure between the composite system and simulated oil is calculated to be 17.02MPa by using IFT extrapolation method, and the minimum miscible pressure is calculated to be 17.02MPa with pure CO 2 The system is not quite different.
The method of example 1 was used to calculate CO at different pressures 2 The composite system was used to simulate oil extraction. The mass fraction of the TGDE cosolvent is 3.0%, the simulated oil extraction rate reaches 86.42% under the pressure of 12.5MPa, the TGDE cosolvent is not added, and under the same pressure, CO 2 The extraction rate of the simulated oil is 30.55%, and the extraction effect is 2.83 times of that of the simulated oil without adding the TGDE cosolvent. Dimethyl ether and CO with the same mass fraction 2 Mixed into CO 2 The composite system has only 28.74% simulated oil extraction rate at a pressure of 12.5 MPa.
The method of example 1 was used to calculate CO at different pressures 2 The composite system simulates the oil swell. The mass fraction of the TGDE cosolvent is 3.0%, the expansion coefficient of the simulated oil reaches 1.42 under the pressure of 12.5MPa, the TGDE cosolvent is not added, and under the same pressure, CO is added 2 The overall expansion coefficient for the simulated oil was 1.35, with an expansion effect of 1.04 times that of the non-ted TEDM co-solvent. Dimethyl ether and CO with the same mass fraction 2 Mixed into CO 2 The coefficient of expansion of the composite system against simulated oil at a pressure of 12.5MPa was 1.31.
Through five rounds of throughput, the CO 2 Shale oil is developed through the composite system, and the core recovery rate is 43.9%. And pure CO 2 Shale oil is developed through huff and puff, the core recovery ratio is 28.6%, and the CO is as follows 2 The recovery ratio of the composite system is improved to 15.3 percent.
Test example 1 solubility of glycol dimethyl ether co-solvents versus temperature and pressure
FIG. 3 is a graph showing the solubility of glycol dimethyl ether co-solvents at various temperatures as a function of pressure. At a certain temperature and a certain pressure, a certain amount of cosolvent is added in CO 2 The solubility calculation formula of (2) is shown in formula 1:
wherein x (%) is CO-solvent in CO 2 Solubility in water; m is m 1 The addition amount of the cosolvent, g; m is M 1 And M 0 Respectively represent cosolvent and CO 2 Molecular weight of (2); ρ 0 Represents CO 2 Density at this temperature and pressure, g/cm 3 ；v 0 Represents CO 2 Volume at this temperature and pressure, cm 3 。
The experimental temperature in fig. 3 (a) was 40 ℃, the experimental temperature in fig. 3 (b) was 50 ℃, and the experimental temperature in fig. 3 (c) was 60 ℃. It can be seen that the glycol dimethyl ether cosolvent is added in CO with the increase of the system pressure 2 The dissolving capacity of the water-soluble polymer is greatly improved. DDME at CO at the same pressure 2 The strongest solubility in water, indicating that DDME is against CO 2 Is the strongest affinity of (C), TEDM times, TGDE in CO 2 The solubility of the organic solvent is not as good as that of the organic solvent, but is far higher than that of cosolvent such as ethanol, butanol and the like in CO 2 Is a solubility in water. With the temperature rise, the glycol dimethyl ether cosolvent is used in CO 2 The dissolution capacity of the polymer is slightly weakened, but the polymer still presents larger dissolution amount in general, and the dissolution amount can reach 0.4mol percent at 12.20MPa by taking TGDE as an example. DDME under conditions of 8.4MPa and 313K at CO 2 The solubility in CO of TGDE can reach 1.000mol% 2 The solubility of the polymer is 0.199mol percent, which indicates that the dissolution amount of the glycol dimethyl ether cosolvent is still relatively considerable under lower pressure. In combination, three glycol dimethyl ether CO-solvents are used in CO 2 The medium has higher dissolving capacity, which indicates that the medium has higher dissolving capacity with CO 2 Has higher affinity with CO 2 After co-dissolution, the polymer is injected into the formation.
Test example 2 test CO 2 Adding different aidsShape of oil droplets after solvent
FIG. 4 shows the CO-solvent mass fraction of 3.0% for different COs 2 Photograph of the shape of the oil droplets in the composite system. Shale oil in CO without any CO-solvent 2 The morphology of (c) remains relatively consistent. However, when the pressure exceeds 14.0MPa, the droplet shape becomes more and more irregular, and the degree of irregularity further increases as the pressure continues to rise. After adding the ethanol and glycol dimethyl ether co-solvents, the irregular variation of the droplets further increases with increasing pressure. Among the three glycol ether cosolvents, DDME has the greatest effect on the morphology of shale oil droplets, and the droplets cannot be condensed under the pressure of 13.0MPa, indicating shale oil-CO 2 The interfacial tension of the composite system is already at a minimum. TEDM, TGDE. At 13.0MPa pressure, without CO-solvent addition, shale oil slowly flows out of the high pressure injector and tends to aggregate, while in the case of DDME-containing CO 2 In the composite system, shale oil presents smoke. The addition of DDME can enhance the CO of shale oil 2 Diffusion in (C) at the same time promote CO 2 Dissolution into the oil results in a decrease in interfacial tension between the two.
Test example 3CO 2 Interfacial tension between the oil and the oil after adding different cosolvents
FIG. 5 shows the CO-solvent mass fraction of 3.0% at different COs 2 Interfacial tension graph between the composite system and oil. It can be seen that shale oil-CO as the pressure increases gradually 2 The interfacial tension value of the composite system gradually decreases. The presence of the cosolvent can reduce interfacial tension. Under the same pressure, CO containing DDME 2 The interfacial tension value of the composite system and shale oil is the lowest. And CO containing ethanol 2 The interfacial tension between the composite system and shale oil is higher than that of CO containing DDME 2 Interfacial tension of the composite system and shale oil. CO containing trace TEDM 2 Composite system and CO containing trace TGDE 2 The interfacial tension values of the composite system and shale oil are low, which indicates that the addition of trace TEDM and TGDE can effectively promote CO 2 Polarity of (C) and enhance CO 2 And interdiffusion of both oils. At the same time can be found inDDME-containing CO 2 Composite system and shale oil and CO containing ethanol 2 In the composite system and the shale oil system, a strong linear correlation exists between the interfacial tension value and the pressure. In addition, when the pressure reaches 13.0MPa, the shale oil is in CO 2 No more droplets are formed in the composite system and therefore the interfacial tension value cannot be calculated.
Test example 4 CO at different gas-oil ratios 2 Extraction and expansion of oil by composite systems
FIG. 6 is a graph of pure CO at different gas-oil ratios 2 Extraction and swelling of oil. FIG. 6 (a) is CO at different gas-oil ratios 2 Extraction and expansion of oil. It can be seen that as the pressure increases gradually, the CO 2 The extraction and expansion of shale oil increases gradually. The difference is that the expansion increases logarithmically, while the extraction increases "S". When the pressure is lower than 11.0MPa, the extraction amount is lower than the expansion amount. When the pressure is more than 11.0MPa, the extraction amount is much more than the expansion amount. I.e. when the pressure is low, CO 2 Has a main effect on the expansion effect of shale oil, and has an unobvious extraction effect. When the pressure is more than 11.0MPa, the extraction amount rapidly increases, and the expansion amount relatively slowly increases. At a pressure of 12.0MPa, it can be seen that the expansion increases relatively slowly, while the extraction tends to increase rapidly. When the system pressure is 14.0MPa, shale oil in the inner pipe is completely pumped out of the inner pipe. FIG. 6 (b) is CO at different gas-oil ratios 2 Extraction rate and expansion rate of oil. It can be seen that shale oil and CO 2 The mass ratio of (c) also affects the expansion and extraction properties. At higher pressure, CO 2 The swelling effect on the oil is still strong, which indicates CO 2 The swelling effect on the oil plays an important role in the development of shale oil. CO as the shale oil quality fraction increases under the same temperature and pressure conditions 2 The expansion and extraction effects of (a) are improved.
FIG. 7 is a CO containing 1% DDME by mass 2 The oil extraction and swelling capacity of the composite system are plotted, FIG. 8 is a graph of CO with 1% DDME by mass 2 Extraction and expansion ratio bar graph of the composite system for oil. From the figure, it can be seen thatCO added to DDME 2 The extraction and expansion of shale oil by the composite system is greatly changed. CO at pressures of 8.0 and 9.5MPa 2 The extraction amount and extraction rate of the composite system to shale oil are compared with the extraction rate of the composite system to the single CO 2 And the oil system parameters decrease more greatly, while the expansion and expansion rate increase more significantly. This is because the pressure has not yet reached DDME at CO 2 Cloud point pressure in (a). When the pressure was increased to 11.0MPa, both the extraction and expansion effects were greatly enhanced in the presence of DDME. CO at 11.0MPa 2 The expansion amount of the composite system to shale oil is 1.75 times that of the composite system without adding the cosolvent, and the extraction amount is 2.25 times that of the composite system without adding the cosolvent. The results show that DDME is at CO 2 Can accelerate the dissolution of crude oil into CO 2 The diffusion of DDME in crude oil can increase the dissolved CO in crude oil 2 Molecules, thereby promoting expansion of the crude oil. CO-philic due to DDME molecules 2 And lipophilicity, can be simultaneously dissolved in oil and CO 2 In the process, the extraction and expansion effects are enhanced.
The invention aims at a shale reservoir layer with a micro-nano pore structure to construct CO suitable for shale oil development in micro-nano pores 2 Composite systems useful for reducing CO during shale oil displacement 2 -interfacial tension of oil, reduction of CO 2 -oil miscible pressure and lifting CO 2 The extraction expansion effect, the stability is better, the compatibility is good, and the phase separation is not easy to occur under certain temperature and pressure. CO 2 The compound system is CO 2 And glycol dimethyl ether cosolvent, and the glycol dimethyl ether cosolvent is mixed in CO 2 Has higher solubility and can be combined with CO under the condition of lower pressure 2 Realize miscibility, and compared with cosolvent such as ethanol, butanol, acetone and the like, the glycol dimethyl ether cosolvent and CO 2 The affinity is higher.
CO used in the present invention 2 The composite system can be applied to medium-low permeability oil reservoirs, is also suitable for low-pore low-permeability shale reservoirs, particularly reservoirs rich in micro-nano pore structures, and can effectively avoid CO 2 Occurrence of composite system blocking stratum. The invention selects the low molecular weight cosolvent which has extremely low volatility compared with the low molecular weight liquid cosolvent such as ethanol, butanol, acetone and the like, and has the same volatility as CO 2 The affinity is stronger. Meanwhile, the glycol dimethyl ether cosolvent is liquid at normal temperature and pressure, and compared with the gaseous cosolvent such as dimethyl ether, methane, propane and the like with lower molecular weight, the glycol dimethyl ether cosolvent can strengthen CO 2 Is the polarity of shale oil molecules and CO 2 The molecules play a role in reducing interaction energy and promote CO 2 Dissolution into oil and oil to CO 2 Diffusion in the gas turbine to enhance CO 2 Interaction with oil. The gaseous cosolvent such as dimethyl ether, methane, propane and the like is the cosolvent which inhibits volatilization of light components in crude oil, so that the viscosity of the crude oil is not excessively high, but the viscosity of the crude oil is high to CO 2 Polarity and CO 2 The performance is not effective, and the gaseous cosolvent can exert the effect by needing larger addition amount. The low molecular weight ethylene glycol dimethyl ether cosolvent is essentially different from the common low molecular weight liquid cosolvent such as ethanol, butanol and the like, and the low molecular weight gaseous cosolvent such as dimethyl ether, methane, propane and the like.
CO of the invention 2 The mixed phase pressure and interfacial tension of the composite system and shale oil are lower, and CO 2 The extraction performance and the expansion performance of the composite system to shale oil are more excellent. At present CO injection 2 Shale oil development is mainly carried out by huff and puff development, which means CO 2 The composite system can realize CO through the action of low miscible pressure and low interfacial tension with shale oil 2 The shale oil in the low-pore low-permeability reservoir structure is carried out in the depressurization production process through the stronger extraction effect and the expansion effect, so that the shale oil recovery ratio is improved. On the one hand, the gaseous cosolvent can not promote CO 2 Taking low molecular weight gaseous cosolvent dimethyl ether as an example, adding trace dimethyl ether and CO 2 Mixing the formed CO 2 Composite system and pure CO 2 The effect of the composite system is not quite different. On the other hand, the method has little effect on the extraction capacity and the expansion capacity of crude oil, but has adverse effect on the extraction capacity and the expansion capacity of simulated oil。
CO of the invention 2 Even in the process of depressurization production of the throughput development mode, the compound system contains CO 2 The composite system does not generate phase separation phenomenon, the cosolvent is not easy to separate out, and the cosolvent can be combined with CO 2 Keep the mixed state, avoid like other COs 2 Composite systems are susceptible to co-solvent precipitation and are limited in shale reservoir applications.
Claims (9)
1. CO suitable for shale oil development in micro-nano pores 2 The composite system is characterized by comprising the following components in percentage by mass: 1.0 to 3.0 percent of cosolvent and the balance of CO 2 ；
The cosolvent is a nonionic cosolvent and comprises one or more of ethylene glycol dimethyl ether cosolvents.
2. CO suitable for shale oil development in micro-nanopores as recited in claim 1 2 The compound system is characterized in that the cosolvent comprises diethylene glycol dimethyl ether DDME, triethylene glycol dimethyl ether TEDM and ethylene glycol diglycidyl ether TGDE.
3. CO suitable for shale oil development in micro-nanopores as recited in claim 2 2 The composite system is characterized in that the CO suitable for shale oil development in micro-nano pores 2 The composite system consists of the following components in percentage by mass: 3.0% cosolvent and the balance of CO 2 。
4. CO suitable for shale oil development in micro-nanopores as recited in claim 1 2 The preparation method of the composite system is characterized by comprising the following steps:
s1, measuring cosolvent and CO with a set mass ratio at a set temperature 2 Cloud point pressure of the mixture;
s2, mixing the cosolvent and CO according to the set mass ratio 2 The mixture is mixed under the pressure higher than the cloud point, thus obtaining CO suitable for the development of shale oil in micro-nano pores 2 A composite system.
5. The CO of claim 4 suitable for shale oil development in micro-nanopores 2 A process for preparing a composite system, characterized in that said mixing above cloud point pressure comprises mixing 4-5MPa above cloud point pressure.
6. CO suitable for development of shale oil in micro-nano pores 2 The method for huff-puff development of the shale oil by the composite system is characterized by comprising the following steps of:
(a) Measurement of CO 2 Interfacial tension between the composite system and oil, and calculating to obtain CO 2 Minimum miscible pressure between the composite system and the oil;
(b) Loading the saturated oil of the experimental rock core into a rock core holder, and applying confining pressure;
(c) Injecting the CO suitable for shale oil development in micro-nano pores 2 The throughput process is carried out by the composite system;
(d) Repeating the step (c) for a plurality of rounds of throughput.
7. The use of CO as in claim 6 for shale oil development in micro-nanopores 2 The method for huff-and-puff development of shale oil by a composite system is characterized in that the huff-and-puff process in the step (d) comprises a gas injection stage, a well soaking stage and a production stage;
In the production stage, when the pressure of the outlet end of the core holder is higher than that of the CO suitable for shale oil development in the micro-nano pores 2 At the mixed phase pressure of the composite system and the oil, the production is carried out at the pressure drop speed of 0.2 MPa/h; when the pressure of the outlet end of the core holder is lower than the CO suitable for shale oil development in the micro-nano pores 2 The composite system was produced at a pressure drop rate of 2MPa/h at the miscible pressure of the oil.
8. The use of CO as in claim 6 for shale oil development in micro-nanopores 2 A method for huff-puff development of shale oil by a composite system is characterized in that,in the step (b), the applying the confining pressure includes adjusting a pressure of the oil saturated into the core after the applying the confining pressure.
9. A CO suitable for shale oil development in micro-nanopores as recited in any of claims 1-3 2 The composite system reduces CO 2 -interfacial tension of oil, reduction of CO 2 -oil miscible pressure and lifting CO 2 The application of extraction expansion rate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410033634.0A CN117887440A (en) | 2024-01-09 | 2024-01-09 | CO suitable for shale oil development in micro-nano pores 2 Composite system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410033634.0A CN117887440A (en) | 2024-01-09 | 2024-01-09 | CO suitable for shale oil development in micro-nano pores 2 Composite system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117887440A true CN117887440A (en) | 2024-04-16 |
Family
ID=90646959
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410033634.0A Pending CN117887440A (en) | 2024-01-09 | 2024-01-09 | CO suitable for shale oil development in micro-nano pores 2 Composite system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117887440A (en) |
-
2024
- 2024-01-09 CN CN202410033634.0A patent/CN117887440A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2796663C (en) | Systems and methods for producing oil and/or gas | |
| CN111909679B (en) | Preparation method and application of composition for reducing minimum miscible pressure of carbon dioxide and crude oil based on aerosol surfactant | |
| US20010018975A1 (en) | Chemically assisted thermal flood process | |
| CN105257264A (en) | Method for improving carbon dioxide flooding recovery ratio by using surfactant | |
| Bhicajee et al. | Effect of different low salinity flooding schemes and the addition of alkali on the performance of low-salinity waterflooding during the recovery of heavy oil from unconsolidated sandstone | |
| CN116792093B (en) | Foam composite flooding gas injection medium optimization and synchronous burial experiment device and method | |
| Ding et al. | Potential to enhance CO2 flooding in low permeability reservoirs by alcohol and surfactant as co-solvents | |
| Chahardowli et al. | Experimental investigation of the use of the dimethyl ether/polymer hybrid as a novel enhanced oil recovery method | |
| Chahardowli et al. | Experimental investigation of dimethyl ether/polymer hybrid as an enhanced oil recovery method | |
| CN107828401B (en) | Enhanced CO2Oil displacement additive capable of mutual dissolving with crude oil and reducing viscosity of crude oil | |
| Zargar et al. | Evaluation of a new agent for wettability alteration during enhanced oil recovery | |
| Hao et al. | N 2-foam-assisted CO 2 huff-n-puff process for enhanced oil recovery in a heterogeneous edge-water reservoir: experiments and pilot tests | |
| CN108049854B (en) | By using CO2Oil displacement method for improving crude oil recovery ratio by using oil displacement additive | |
| CN117887440A (en) | CO suitable for shale oil development in micro-nano pores 2 Composite system | |
| CN113004882A (en) | Microemulsion type imbibition agent, preparation method thereof and oil displacement type fracturing fluid system | |
| WO2012170835A1 (en) | Modified nonionic surfactant formulations for enhanced oil recovery | |
| CN117345185A (en) | Method for exploiting thick oil by micro-emulsion imbibition displacement oil fracturing assisted by steam huff and puff | |
| CN113563546B (en) | Polystyrene modified nano silicon dioxide and efficient foam oil displacement agent and preparation thereof | |
| CN108048066A (en) | Promote CO2The chemical assistant of gas drive process oil recovery factor | |
| CN112177603B (en) | Quantitative evaluation of CO in supercritical state 2 Method for extracting component content of crude oil | |
| Torabi et al. | Performance of CO2 huff-and-puff process in fractured media (experimental results) | |
| Wang et al. | Effect of CO2 injection on interfacial tension of oil-formation water system under high temperature and pressure | |
| CN117746729B (en) | System and method for simulating natural gas foam composite oil displacement dynamic law through double pipes | |
| Li | Optimum Timing for CO2-EOR After Waterflooding and Soaking Effect on Miscible CO2 Flooding in a Tight Sandstone Formation | |
| US12006804B2 (en) | Method for recovering hydrocarbons with an organic solvent injection blend |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |