CN106840790A

CN106840790A - CO is tested based on tubule consolidated model long2The method and system of crude oil MMP

Info

Publication number: CN106840790A
Application number: CN201611208581.3A
Authority: CN
Inventors: 刘丽; 皮彦夫; 李静; 万雪; 柏明星; 杨昕谅
Original assignee: Northeast Petroleum University
Current assignee: Northeast Petroleum University
Priority date: 2016-12-23
Filing date: 2016-12-23
Publication date: 2017-06-13
Anticipated expiration: 2036-12-23
Also published as: CN106840790B

Abstract

CO is tested based on tubule consolidated model long the invention provides one kind₂The method and system of crude oil MMP, method is：Low permeability pay relevant parameter is obtained, laboratory experiment is made with tubule consolidated model long, back-up sand tubule is obtained；According to stratum crude oil sample and injection gas sample product, saturated oils is carried out to thin tube model by the experimental provision for connecting in advance, obtain in-place oil saturation pressure；Multiple experimental pressures are chosen, and carries out multiple slim-tube test, the graph of relation of oil displacement efficiency when obtaining injecting in each slim-tube test 1.2 times of pore volumes and displacement pressure；Pressure value corresponding to the intersection point of immiscible phase section and mixed phase section curve is minimum miscibility pressure (MMP) value.It is to simulate the tubule consolidated model long with micropore made under the conditions of hyposmosis actual reservoir present invention employs a kind of back-up sand tubule consolidated model long, the minimum miscibility pressure accuracy measured with the thin tube model is higher, and with reasonability and science.

Description

CO is tested based on tubule consolidated model long2The method and system of-crude oil MMP

Technical field

Made the present invention relates to a kind of technical field of oil field development laboratory experiment, more particularly to tubule consolidated model long Method and minimum miscibility pressure method of testing.

Background technology

Have in terms of two on minimum miscibility pressure (MMP) acquisition methods at present：Theoretical calculation method and experimental determining method. Theoretical calculation method is applied to the situation for being inconvenient to carry out measuring, and error is more relatively large.Comparatively, laboratory experiment Method for measuring is more accurate, the CO tested wherein in slim-tube test method₂It is related to the porous media in back-up sand tubule with crude oil, It is to use most extensive and degree of recognition highest method at present.But also there is pertinent literature to carry slim-tube test produced problem at present Some queries are gone out：Pore character influence physical property of fluid, due to thin tube model pore structure (back-up sand is without cementing) with it is true Real rock core is different, thus the MMP values measured with the experiment are used as CO under reservoir condition₂The MMP values of-crude oil system, are present certain Theoretical defects.

Some are had at present on CO₂The research of-crude oil minimum miscibility pressure (MMP), remains asking in following several respects Topic：

First, in the method for testing of minimum miscibility pressure, tested media does not have the simulation of overlength rock core micropore, minimum mixed phase The simulation of pressure can lose accuracy.Back-up sand tubule is used in slim-tube test, hole relatively high is hypertonic, porosity is stored up than actual Layer hole is much larger, does not have micropore, and larger difference is there is also with actual reservoir.Existing slim-tube test shows：For extra-high (21.38 darcy) tubule is oozed, when porosity increases, MMP can increase, when porosity reduces, MMP can reduce.This explanation hole Porosity influences whether the measure of MMP.If porosity has had influence on the measure of MMP, the hole of porosity and larynx and micro- are determined Hole will inevitably have influence on the measurement result of MMP.The actual core test that Liu Yu chapters et al. are used have modified the survey of MMP Test result, it was confirmed that reservoir structure exists on MMP to be influenceed, but the rock core for being used is also shorter relative to slim-tube test, only There is 1m.If do not considered from the cycle of experiment, only consider with representativeness from the academic accuracy of experiment, also lack use at present The research of the overlength core model this respect with micropore.

2nd, the influence of the permeability of hyposmosis actual reservoir is not accounted in current minimum miscibility pressure test, especially It is low permeability reservoir permeability.Only have slim-tube test to be related to simulate the porous media of reservoir in current method of testing, on Text is mentioned simulation and is carried out in the case of extra-high oozing, even the permeability after change is still extra-high permeability.It is extra-high The fingering phenomenon of permeability is inevitably particularly evident, more in addition without clear and definite：That is exactly when permeability occurs significantly During change, whether porosity also there occurs large change, and how the influence that porosity brings eliminates.

Therefore, defect of the prior art is, existing CO₂In the research experiment of-crude oil minimum miscibility pressure (MMP), fill out Permeability under the size and hyposmosis actual reservoir of sand capillary pore degree can influence the test result of MMP, in addition, existing experiment The thin tube model of middle use can also be surveyed because of the limitation of its size, and to the limitation of actual reservoir permeability simulation to MMP Test result can produce inevitably influence.

The content of the invention

For above-mentioned technical problem, the present invention provides a kind of based on tubule consolidated model long test CO₂The side of-crude oil MMP Method and system, employ a kind of back-up sand tubule consolidated model long, and the back-up sand tubule consolidated model long is the simulation actual storage of hyposmosis The tubule consolidated model long with micropore made under the conditions of layer, the CO measured with the thin tube model₂- crude oil minimum mixed phase Pressure (MMP) has reasonability and science, and the minimum miscibility pressure accuracy for measuring is higher, the science simulation to laboratory experiment Have great importance.

In order to solve the above technical problems, the technical scheme that the present invention is provided is：

The present invention provides a kind of based on tubule consolidated model long test CO₂The method of-crude oil MMP, including：

Step S1, the actual reservoir data according to mining site obtains low permeability pay relevant parameter, and the parameter includes oil reservoir Porosity, permeability and reservoir temperature；

Step S2, according to the low permeability pay relevant parameter, makes laboratory experiment tubule consolidated model long, and obtain Back-up sand tubule, the tubule consolidated model long is the thin tube model for possessing micropore；

Step S3, according to stratum crude oil sample and injection gas sample product, by the experimental provision that connects in advance to described thin Tube model carries out saturated oils, obtains in-place oil saturation pressure；

Step S4, according to current strata pressure, chooses multiple experimental pressures, and carried out repeatedly using the back-up sand tubule thin Pipe is tested, and the slim-tube test includes constant speed displacement test and constant pressure displacement test, obtains injecting 1.2 times in each slim-tube test The graph of relation of oil displacement efficiency and displacement pressure during pore volume；

Step S5, according to the graph of relation, obtains the pressure corresponding to the intersection point of immiscible phase section and mixed phase section curve Value, the pressure value is minimum miscibility pressure (MMP) value.

The present invention provides a kind of based on tubule consolidated model long test CO₂The method of-crude oil MMP, its technical scheme is：First Actual reservoir data according to mining site, obtain low permeability pay relevant parameter, the parameter include oil reservoir porosity, permeability and Reservoir temperature；Then according to the low permeability pay relevant parameter, laboratory experiment tubule consolidated model long is made, and filled out Sand tubule, the tubule consolidated model long is the thin tube model for possessing micropore；

Then according to in-place oil sample and injection gas sample product, by the experimental provision that connects in advance to the tubule mould Type carries out saturated oils, obtains in-place oil saturation pressure；Then according to current strata pressure, multiple experimental pressures are chosen, and adopt Multiple slim-tube test is carried out with the back-up sand tubule, the slim-tube test includes constant speed displacement test and constant pressure displacement test, obtains The graph of relation of oil displacement efficiency and displacement pressure in each slim-tube test during 1.2 times of pore volumes of injection；Finally according to The graph of relation, obtains the pressure value corresponding to the intersection point of immiscible phase section and mixed phase section curve, and the pressure value is minimum Miscible pressure value.

What the present invention was provided tests CO based on tubule consolidated model long₂The method of-crude oil MMP, employs a kind of back-up sand long Tubule consolidated model, the back-up sand tubule consolidated model long be simulate hyposmosis actual reservoir under the conditions of make with micropore Tubule consolidated model long, the CO measured with the thin tube model₂- crude oil minimum miscibility pressure (MMP) has reasonability and science Property, the minimum miscibility pressure accuracy for measuring is higher, and the science simulation to laboratory experiment has great importance.

Further, the back-up sand tubule includes that porosity is constant, the first back-up sand tubule that permeability changes, and permeability It is constant, the second back-up sand tubule that porosity changes.

Further, the back-up sand tubule is made up of the first back-up sand tubule and the connection of second back-up sand tubule, and described the A kind of back-up sand tubule is shaped as horizontal linear section, and second back-up sand tubule is shaped as arc.

Further, in the step S4, slim-tube test is carried out using the back-up sand tubule, specially：

Gas sample product will be injected constant under experimental temperature, the injection gas sample product are CO₂And toluene；

The pipeline of the thin tube model inlet valve for being full of and being rinsed into the experimental provision with the injection gas, by the note Enter atmospheric pressure and be adjusted to the experimental pressure, record the first reading of the experimental provision mesohigh displacement pump under the experimental pressure Number, the thin tube model is the tubule consolidated model long；

Under experimental temperature, experimental pressure and constant injection rate, with the injection gas drive in the thin tube model In-place oil sample, sets displacement velocity, determines that time of measuring is spaced, in each point in time measurement output oil, an air volume, Record the reading and injection pressure of the high pressure displacement pump；

The phase and color change of fluid in observation experiment device mesohigh observation window, after breakthrough of gas, by displacement side Formula is changed to constant pressure displacement；

After the injection gas is accumulated into high pressure displacement 1.20 times of pore volumes of pump, stop displacement, complete slim-tube test.

Further, in the step S2, according to the low permeability pay relevant parameter, laboratory experiment tubule long is made Consolidated model, and back-up sand tubule is obtained, specially：

According to the low permeability pay relevant parameter, with reference to slim-tube test national standard, determine back-up sand tubule length and Internal diameter；

According to the low permeability pay relevant parameter, preparation prepares the material of large-sized model and the content of every kind of material, described Material includes natural landwaste, quartz sand, cement, clay；

By suppressing the multiple large-sized models of modelling, obtain large-sized model permeability, porosity and prepare pressure；

To determine that the back-up sand tubule of length resolves into multistage straightway, will be described many by being segmented the cementing mode of compacting Section straightway carries out tubule consolidated model long and makes, obtain two kinds it is cementing after thin tube model；

According to the porosity and permeability required in experiment, by the connection of described two back-up sand tubules, experiment institute is fabricated to Need the back-up sand tubule of length and quantity.

Second aspect, CO is tested the invention provides one kind based on tubule consolidated model long₂The system of-crude oil MMP, bag Include：

Parameter acquisition module, for the actual reservoir data according to mining site, obtains low permeability pay relevant parameter, the ginseng Number includes oil reservoir porosity, permeability and reservoir temperature；

Back-up sand tubule makes module, for according to the low permeability pay relevant parameter, making laboratory experiment tubule long Consolidated model, and back-up sand tubule is obtained, the tubule consolidated model long is the thin tube model for possessing micropore；

Tubule consolidated model saturated oils module long, for according to stratum crude oil sample and injection gas sample product, by connecting in advance The experimental provision for connecting carries out saturated oils to the thin tube model, obtains in-place oil saturation pressure；

Curve map generation module, it is for according to current strata pressure, choosing multiple experimental pressures and thin using the back-up sand Pipe carries out multiple slim-tube test, and the slim-tube test includes constant speed displacement test and constant pressure displacement test, obtains each tubule reality The graph of relation of oil displacement efficiency and displacement pressure when testing 1.2 times of pore volumes of middle injection；

Minimum miscibility pressure (MMP) value acquisition module, for according to the graph of relation, obtaining immiscible phase section and mixed phase Duan Qu Pressure value corresponding to the intersection point of line, the pressure value is minimum miscibility pressure (MMP) value.

What the present invention was provided tests CO based on tubule consolidated model long₂The system of-crude oil MMP, its technical scheme is：First lead to Parameter acquisition module is crossed, the actual reservoir data according to mining site obtains low permeability pay relevant parameter, and the parameter includes oil reservoir Porosity, permeability and reservoir temperature；Then module is made by back-up sand tubule, according to the low permeability pay relevant parameter, Laboratory experiment tubule consolidated model long is made, and obtains back-up sand tubule, the tubule consolidated model long is possess micropore Thin tube model；

Then by tubule consolidated model saturated oils module long, according to stratum crude oil sample and injection gas sample product, by pre- The experimental provision for first connecting carries out saturated oils to the thin tube model, obtains in-place oil saturation pressure；Then curve is passed through Figure generation module, according to current strata pressure, chooses multiple experimental pressures, and carry out multiple tubule reality using the back-up sand tubule Test, the slim-tube test includes constant speed displacement test and constant pressure displacement test, obtain injecting 1.2 times of holes in each slim-tube test The graph of relation of oil displacement efficiency and displacement pressure during volume；Finally by minimum miscibility pressure (MMP) value acquisition module, according to institute Graph of relation is stated, the pressure value corresponding to the intersection point of immiscible phase section and mixed phase section curve is obtained, the pressure value is minimum mixed Phase pressure value.

What the present invention was provided tests CO based on tubule consolidated model long₂The system of-crude oil MMP, employs a kind of back-up sand long Tubule consolidated model, the back-up sand tubule consolidated model long be simulate hyposmosis actual reservoir under the conditions of make with micropore Tubule consolidated model long, the CO measured with the thin tube model₂- crude oil minimum miscibility pressure (MMP) has reasonability and science Property, the minimum miscibility pressure accuracy for measuring is higher, and the science simulation to laboratory experiment has great importance.

Further, the curve map generation module, specifically for：

Further, the back-up sand tubule makes module, specifically for：

To determine that the back-up sand tubule of length resolves into multistage straightway, will be described many by being segmented the cementing mode of compacting Section straightway carries out tubule consolidated model long and makes, obtain two kinds it is cementing after thin tube model；According to the hole required in experiment Degree and permeability, by the connection of described two back-up sand tubules, are fabricated to the back-up sand tubule of length and quantity needed for experiment.

Brief description of the drawings

In order to illustrate more clearly of the specific embodiment of the invention or technical scheme of the prior art, below will be to specific The accompanying drawing to be used needed for implementation method or description of the prior art is briefly described.

Fig. 1 shows that one kind that first embodiment of the invention is provided is based on tubule consolidated model long and tests CO₂- crude oil The flow chart of the method for MMP；

Fig. 2 shows that one kind that first embodiment of the invention is provided is based on tubule consolidated model long and tests CO₂- crude oil Back-up sand tubule decomposes straightway figure in the method for MMP；

Fig. 3 shows that the present invention provides provided one kind and is based on tubule consolidated model long test CO₂The side of-crude oil MMP Back-up sand tubule connection figure in method；

Fig. 4 shows that the present invention provides provided one kind and is based on tubule consolidated model long test CO₂The side of-crude oil MMP Experimental provision connection figure in method；

Fig. 5 shows that one kind that second embodiment of the invention is provided is based on tubule consolidated model long and tests CO₂- crude oil The schematic diagram of the system of MMP；

Fig. 6 shows that one kind that third embodiment of the invention is provided is based on tubule consolidated model long and tests CO₂- crude oil Model schematic is suppressed in the method and system of MMP；

Fig. 7 shows that one kind that third embodiment of the invention is provided is based on tubule consolidated model long and tests CO₂- crude oil The first tubule consolidated model displacement pressure long and recovery ratio graph of a relation in the method and system of MMP；

Fig. 8 shows that one kind that third embodiment of the invention is provided is based on tubule consolidated model long and tests CO₂- crude oil Second long tubule consolidated model displacement pressure and recovery ratio graph of a relation in the method and system of MMP；

Fig. 9 shows that one kind that third embodiment of the invention is provided is based on tubule consolidated model long and tests CO₂- crude oil Common back-up sand tubule not consolidated model displacement pressure and recovery ratio graph of a relation in the method and system of MMP.

Specific embodiment

The embodiment of technical solution of the present invention is described in detail below in conjunction with accompanying drawing.Following examples are only used for Technical scheme is clearly illustrated, therefore is intended only as example, and protection of the invention can not be limited with this Scope.

Embodiment one

Fig. 1 shows that one kind that first embodiment of the invention is provided is based on tubule consolidated model long and tests CO₂- crude oil The flow chart of the method for MMP；As shown in figure 1, the embodiment of the present invention one provides one kind based on tubule consolidated model long test CO₂The method of-crude oil MMP, including：

Step S1, the actual reservoir data according to mining site obtains low permeability pay relevant parameter, and parameter includes oil reservoir hole Degree, permeability and reservoir temperature；

Step S2, according to low permeability pay relevant parameter, makes laboratory experiment tubule consolidated model long, and obtain back-up sand Tubule, tubule consolidated model long is the thin tube model for possessing micropore；

Step S3, according to stratum crude oil sample and injection gas sample product, by the experimental provision that connects in advance to tubule mould Type carries out saturated oils, obtains in-place oil saturation pressure；

Step S4, according to current strata pressure, chooses multiple experimental pressures, and carry out multiple tubule reality using back-up sand tubule Test, slim-tube test includes constant speed displacement test and constant pressure displacement test, obtain injecting 1.2 times of pore volumes in each slim-tube test When oil displacement efficiency and displacement pressure graph of relation；

Step S5, according to graph of relation, obtains the pressure value corresponding to the intersection point of immiscible phase section and mixed phase section curve, pressure Force value is minimum miscibility pressure (MMP) value.

The present invention provides a kind of based on tubule consolidated model long test CO₂The method of-crude oil MMP, its technical scheme is：First Actual reservoir data according to mining site, obtains low permeability pay relevant parameter, and parameter includes oil reservoir porosity, permeability and oil reservoir Temperature；Then according to low permeability pay relevant parameter, laboratory experiment tubule consolidated model long is made, and obtains back-up sand tubule, Tubule consolidated model long is the thin tube model for possessing micropore；

Then according to in-place oil sample and injection gas sample product, thin tube model is entered by the experimental provision for connecting in advance Row saturated oils, obtains in-place oil saturation pressure；Then according to current strata pressure, multiple experimental pressures are chosen, and use is filled out Sand tubule carries out multiple slim-tube test, and slim-tube test includes constant speed displacement test and constant pressure displacement test, obtains each tubule reality The graph of relation of oil displacement efficiency and displacement pressure when testing 1.2 times of pore volumes of middle injection；Finally according to graph of relation, obtain To immiscible phase section and mixed phase section curve intersection point corresponding to pressure value, pressure value be minimum miscibility pressure (MMP) value.

Wherein, during slim-tube test is carried out, according to current strata pressure, multiple experimental pressures are chosen, and done many Secondary slim-tube test, the relation of oil displacement efficiency and displacement pressure when obtaining injecting 1.2 times of pore volumes.

Specifically, back-up sand tubule includes that porosity is constant, and the first back-up sand tubule that permeability changes, and permeability is constant, The second back-up sand tubule that porosity changes.

According to mining site actual reservoir data, low permeability pay relevant parameter is obtained, parameter includes oil reservoir porosity, infiltration Rate, reservoir temperature etc.；Laboratory experiment tubule consolidated model long, i.e. back-up sand tubule are made according to above-mentioned actual reservoir situation, is filled out Sand tubule is prepared by preparing the device of back-up sand tubule, prepares two kinds of back-up sand tubules, and one kind is constant porosity, and permeability changes The the first back-up sand tubule for becoming, another kind is constant permeability, the second back-up sand tubule that porosity changes.It is thin by both back-up sands Pipe carries out CO₂The measurement of-crude oil minimum miscibility pressure, it is ensured that minimum miscibility pressure is constant in porosity or permeability is constant In the case of the pressure that measures.

Specifically, back-up sand tubule is made up of the first back-up sand tubule and second back-up sand tubule connection, and the first back-up sand is thin Pipe is shaped as horizontal linear section, and second back-up sand tubule is shaped as arc.

Back-up sand tubule as shown in Figure 3, is made up of, i.e., as schemed the first back-up sand tubule and second back-up sand tubule connection Back-up sand tubule 8 and back-up sand tubule 9 shown in 2 are constituted, wherein, the first back-up sand tubule be shaped as horizontal linear section (back-up sand Tubule 8), second back-up sand tubule is shaped as arc (back-up sand tubule 9).

Wherein, back-up sand tubule 8 and back-up sand tubule 9 can be connected by screw thread and nut 6, the TBE (threaded both ends) of back-up sand tubule 8, The two ends band nut 6 of back-up sand tubule 9, spirals according to experiment demand and connects into the shape and length of needs.

Specifically, in step S4, slim-tube test is carried out using back-up sand tubule, specially：

Gas sample product will be injected constant under experimental temperature, injection gas sample product are CO₂And toluene；

The pipeline of the thin tube model inlet valve for being full of and being rinsed into experimental provision with injection gas, by injection atmospheric pressure adjustment To experimental pressure, the initial reading of experimental provision mesohigh displacement pump 10 under record experimental pressure, thin tube model is that tubule long is cementing Model；

Under experimental temperature, experimental pressure and constant injection rate, with injection gas drive for the in-place oil in thin tube model Sample, sets displacement velocity, determines that time of measuring is spaced, and in each point in time measurement output oil, an air volume, records high pressure The reading and injection pressure of displacement pump 10；

The phase and color change of fluid in observation experiment device mesohigh observation window 14, after breakthrough of gas, by displacement Mode is changed to constant pressure displacement；

After injecting gas and accumulating 1.20 times of pore volumes into high pressure displacement pump 10, stop displacement, complete slim-tube test.

Carrying out the detailed process of slim-tube test is：

1) experimental provision is connected；

As shown in figure 4, changing the thin tube model in device connection figure into porosity of the invention constant and permeability respectively The tubule consolidated model long (back-up sand tubule 8) for changing carries out a slim-tube test, then changes the constant hole of permeability of the invention into The tubule consolidated model long (back-up sand tubule 9) for spending change carries out a slim-tube test, finally changes common back-up sand tubule into not cementing Model carries out a slim-tube test.

2) saturation of in-place oil sample；

Make thin tube model saturated oils using in-place oil sample, toluene and experimental provision.

3) displacement test；

(1) it is injection gas sample product are constant under experimental temperature；

(2) it is full of and is rinsed to the pipeline of thin tube model inlet valve with injection gas.Injection atmospheric pressure is adjusted to experiment pressure Power, records the initial reading of pump under the pressure；

(3) it is former for the stratum in thin tube model with injection gas drive under experimental temperature, experimental pressure and constant injection rate Oil samples, and set displacement velocity.Determine that time of measuring is spaced, in each point in time measurement output oil, an air volume, record The reading of high pressure displacement pump 10, injection pressure.Note observing the phase and color change of fluid in high pressure observation window 14；

(4) after breakthrough of gas, displacement mode is changed to constant pressure displacement, data acquisition density is increased as far as possible；

(5) after injection gas is accumulated into 1.20 times of pore volumes of pump, displacement is stopped；

(6) thin tube model is cleaned, preparation is tested next time.

Slim-tube test is exactly to do constant speed experiment and constant pressure experimentation using back-up sand tubule, obtains oil displacement efficiency with displacement pressure Relation.

Specifically, in step S2, according to low permeability pay relevant parameter, laboratory experiment tubule consolidated model long is made, And back-up sand tubule is obtained, specially：

According to low permeability pay relevant parameter, with reference to slim-tube test national standard, the length and internal diameter of back-up sand tubule are determined；

According to low permeability pay relevant parameter, preparation prepares the material of large-sized model and the content of every kind of material, and material includes Natural landwaste, quartz sand, cement, clay；

By suppressing modelling multiple large-sized model, obtain large-sized model permeability, porosity and prepare pressure；

To determine that the back-up sand tubule of length resolves into multistage straightway, it is by being segmented compacting cementing mode that multistage is straight Line segment carries out tubule consolidated model long and makes, obtain two kinds it is cementing after thin tube model；

According to the porosity and permeability required in experiment, two kinds of back-up sand tubules are connected, be fabricated to long needed for experiment is used The back-up sand tubule of degree and quantity.

Wherein, combination 6, the specific preparation process of back-up sand tubule is：

(1) prepare natural landwaste, quartz sand, cement, clay, carry out the preparation of pressure test experiment；

1. size distribution according to the hyposmosis purpose reservoir for selection, cement content, clay content are simulated Prepare, multiple large-sized models are prepared using different pressures；

The pressing process of large-sized model is：1. compacting tool set is prepared；2. sorting；3. stirring material；4. it is die-filling to strike-off；5. pressurize Setting.

Natural landwaste adds the purpose of sorting to be able to prepare the thin tube model for possessing micropore.

2. the large-sized model that will be suppressed is put into insulating box 16, sets operating temperature and the working time of insulating box 16；

3. by the large-sized model of drying drill through standard sample test permeability and porosity, and record the match is successful with actual reservoir Prepare pressure, as the pressure for preferably going out；

Large-sized model need to make two series, including porosity is constant and permeability changes and the constant porosity of permeability becomes The two kinds of series models changed.Two kinds of series model ways are identical, completed by above-mentioned three step.

Standard sample permeability is measured by permeability instrument.

Standard sample porosity method of testing is as follows：

1. standard sample chisel bit is drilled to the cylinder that some specifications are diameter 2.5cm, 10cm high；

2. with the dry weight of every cylinder of electronic balance weighing and record；

3. cylinder is placed in vacuum tank, and pours into simulated formation water, until not having cylinder 2cm highly；

4. vavuum pump is opened, is evacuated in vacuum tank untill there is no bubble；

5. cylinder is taken out, is slightly wiped with filter paper, with the weight in wet base of every cylinder of electronic balance weighing and recorded；

6. the porosity of cylinder is calculated, computing formula is

(2) according to mining site actual reservoir data, with reference to slim-tube test national standard SY/T 6573-2003, determine that back-up sand is thin The length of pipe, more than 12 meters of slim-tube test national standard SY/T 6573-2003 requirement back-up sands capillary length, back-up sand capillary inside diameter It is required that between 3.5mm-8mm.In view of conventional back-up sand tubule does not have cement, so internal diameter is excessive to occur that injectant can be from Jie The situation of channelling between matter and back-up sand tubule, causes test experiments to fail.The present invention will can suitably be amplified using cementing medium Internal diameter, is easy to dose cementing material in back-up sand tubule.

(3) will determine that the back-up sand tubule of length resolves into multistage straightway, be divided into two types, the first has been that level is straight Line segment, second for compacting when straightway, after be changed into arc (band bilateral nut 6).According to large-sized model permeability, porosity and Prepare pressure carries out tubule consolidated model (two kinds of back-up sand tubules) making by being segmented the cementing mode of compacting；

With reference to Fig. 6, two kinds of back-up sand tubule manufacturing process are as follows：

1. by two kinds of straightway back-up sand tubule sample back-up sand；

Above-mentioned back-up sand tubule is fixed during actual compacting is placed on base plate 3, be distributed using natural landwaste, quartz sand size and Clay ratios and adhesive composition determine material component, rub material with the hands sand by screen filtration, uniformly insert segmentation tubule Afterwards, using pressure testing machine, material in back-up sand tubule is pressurizeed using pressure head, correspondence tubule is calculated according to preferred pressure Pressure used by sectional area carries out pressurization making.

2. the straightway back-up sand tubule sample that sand will be completed is put into insulating box 16 and heats drying；

3. the straightway back-up sand tubule sample of drying is carried out into permeability porosity determination.Requirement is such as met according to above-mentioned step Suddenly multiple straightways being prepared again, the first straightway being put into insulating box 16 and is dried, second straightway is being suppressed Material becomes the arc shape for needing before not yet solidifying, place into baking and curing in insulating box 16.

Straightway back-up sand tubule is divided into two series, including porosity is constant and permeability changes and permeability not variable orifice Two kinds of series of porosity change.Two kinds of serial back-up sand tubule ways are identical, completed by above-mentioned three step.

(4) by the foregoing two kinds of back-up sand tubules connection made, required length sum is made according to test experiments group numeral system The tubule consolidated model long of amount；

Two kinds of back-up sand tubules are spiraled connection by the internal and external threads at two ends, obtains that porosity is constant, what permeability changed First back-up sand tubule, and permeability is constant, the second back-up sand tubule that porosity changes.

Embodiment two

Fig. 5 shows that one kind that second embodiment of the invention is provided is based on tubule consolidated model long and tests CO₂- crude oil The schematic diagram of the system of MMP；As shown in figure 5, the embodiment of the present invention two provides one kind based on tubule consolidated model long test CO₂The system 10 of-crude oil MMP, including：

Parameter acquisition module 101, for the actual reservoir data according to mining site, obtains low permeability pay relevant parameter, ginseng Number includes oil reservoir porosity, permeability and reservoir temperature；

Back-up sand tubule makes module 102, for according to low permeability pay relevant parameter, making laboratory experiment tubule glue long Knot model, and back-up sand tubule is obtained, tubule consolidated model long is the thin tube model for possessing micropore；

Tubule consolidated model saturated oils module 103 long, for according to stratum crude oil sample and injection gas sample product, by advance The experimental provision for connecting carries out saturated oils to thin tube model, obtains in-place oil saturation pressure；

Curve map generation module 104, it is for according to current strata pressure, choosing multiple experimental pressures and thin using back-up sand Pipe carries out multiple slim-tube test, and slim-tube test includes constant speed displacement test and constant pressure displacement test, in obtaining each slim-tube test The graph of relation of oil displacement efficiency and displacement pressure during 1.2 times of pore volumes of injection；

Minimum miscibility pressure (MMP) value acquisition module 105, for according to graph of relation, obtaining immiscible phase section with mixed phase section curve Intersection point corresponding to pressure value, pressure value be minimum miscibility pressure (MMP) value.

What the present invention was provided tests CO based on tubule consolidated model long₂The system 10 of-crude oil MMP, its technical scheme is：First By parameter acquisition module 101, the actual reservoir data according to mining site obtains low permeability pay relevant parameter, and parameter includes oil Layer porosity, permeability and reservoir temperature；Then module 102 is made by back-up sand tubule, according to low permeability pay relevant parameter, Laboratory experiment tubule consolidated model long is made, and obtains back-up sand tubule, tubule consolidated model long is the tubule for possessing micropore Model；

Then by tubule consolidated model saturated oils module 103 long, according to stratum crude oil sample and injection gas sample product, pass through The experimental provision for connecting in advance carries out saturated oils to thin tube model, obtains in-place oil saturation pressure；Then curve map is passed through Generation module 104, chooses according to current strata pressure, chooses multiple experimental pressures, and carry out multiple tubule using back-up sand tubule Experiment, slim-tube test includes constant speed displacement test and constant pressure displacement test, obtains injecting 1.2 times of pore-bodies in each slim-tube test The graph of relation of oil displacement efficiency and displacement pressure during product；Finally by minimum miscibility pressure (MMP) value acquisition module 105, according to pass It is curve map, obtains the pressure value corresponding to the intersection point of immiscible phase section and mixed phase section curve, pressure value is minimum miscibility pressure (MMP) value.

What the present invention was provided tests CO based on tubule consolidated model long₂The system 10 of-crude oil MMP, employs a kind of length and fills out Sand tubule consolidated model, the back-up sand tubule consolidated model long be simulate hyposmosis actual reservoir under the conditions of make with micropore Tubule consolidated model long, the CO measured with the thin tube model₂- crude oil minimum miscibility pressure (MMP) has reasonability and section The property learned, the minimum miscibility pressure accuracy for measuring is higher, and the science simulation to laboratory experiment has great importance.

Specifically, curve map generation module 104, specifically for：

After injection gas is accumulated into high pressure displacement 101.20 times of pore volumes of pump, stop displacement, complete slim-tube test.

Carrying out the detailed process of slim-tube test is：

1) experimental provision is connected；

As shown in figure 4, changing the thin tube model in device connection figure into porosity of the invention constant and permeability respectively The tubule consolidated model long (back-up sand tubule 8) for changing carries out a slim-tube test, then changes the constant hole of permeability of the invention into The tubule consolidated model long (back-up sand tubule 9) for spending change carries out a slim-tube test.

2) saturation of in-place oil sample；

3) displacement test；

(5) after accumulating into 1.20 times of pore volumes of pump, displacement is stopped；

(6) thin tube model is cleaned, preparation is tested next time.

Specifically, back-up sand tubule makes module 102, specifically for：

Wherein, the specific preparation process of back-up sand tubule is：

1. size distribution according to the hyposmosis purpose reservoir for selection, cement content, clay content are simulated Prepare, multiple large-sized models are prepared using different pressures, wherein, large-sized model refers to tubule consolidated model long；

Standard sample permeability is measured by permeability instrument.

Standard sample porosity method of testing is as follows：

6. the porosity of cylinder is calculated, computing formula is

Two kinds of back-up sand tubule manufacturing process are as follows：

1. by two kinds of straightway back-up sand tubule sample back-up sand；

Embodiment three

Tubule consolidated model long is based on based on the one kind in the embodiment of the present invention one and tests CO₂The method of-crude oil MMP, and One kind in embodiment two is based on tubule consolidated model long and tests CO₂The system of-crude oil MMP；Water is in for the exploitation of certain block Later stage is driven, in order to extend recovery time, decision uses CO₂Drive further to improve recovery ratio.It is advanced before implementing measure Row simulating lab test, determines CO₂- crude oil minimum miscibility pressure (MMP).With reference to Fig. 2 to Fig. 4, and Fig. 6 to Fig. 9, to this Invention is described further, and its step is as follows：

Step one：According to mining site actual reservoir data, low permeability pay relevant parameter is obtained, parameter includes oil reservoir hole Degree, permeability, reservoir temperature etc.；

According to the stratum relevant parameter that mining site actual reservoir data is obtained：Oil reservoir porosity is 15%, and mean permeability is 40×10^-3μm², original saturation pressure is 17.2Mpa, and current strata pressure is 17MPa, and original gasoline ratio is 168m³/ t, crude oil Density is 0.825, and reservoir temperature is 75 DEG C.

Step 2：Laboratory experiment tubule consolidated model long and common back-up sand tubule are made according to above-mentioned actual reservoir situation Not consolidated model；Wherein, consolidated model is not used for comparing experiment common back-up sand tubule；

1) slim-tube test national standard SY/T 6573-2003 are combined first, determine the length of back-up sand tubule；

According to slim-tube test national standard SY/T 6573-2003, and combine simulation and require, it is determined that back-up sand capillary length It it is 15 meters, capillary inside diameter is 8mm.

2) carry out tubule consolidated model making by being segmented the cementing mode of compacting, will be cementing after each section of thin tube model enter Row permeability, porosity test, meet after requiring, spiral and are threadedly coupled into the back-up sand tubule for needing size；

Specifically include following steps：

(1) natural landwaste, quartz sand, cement content, clay content, pressure test preparing experiment；

Fig. 6 shows that one kind that third embodiment of the invention is provided is based on tubule consolidated model long and tests CO₂- crude oil Model schematic is suppressed in the method and system of MMP；As shown in fig. 6, be the schematic diagram of large-sized model compacting tool set, including：

Pressing plate 1, grommet 2, base plate 3, double threaded screw 4, side plate long 5, nut 6 and short side plate 7；

Pressing plate 1 embeds grommet 2, and pressing plate 1 is moved by grommet 2；

Base plate 3 includes the groove of base plate 3, by the groove of base plate 3 and short side plate 7 and the nested encryptions of side plate long 5；

Side plate long 5 includes the groove of side plate long 5, by the groove of side plate long 5 and the nested encryptions of short side plate 7；

There are two through holes at the both ends of side plate long 5, and double threaded screw 4 is fixed on length by through hole facing each other by nut 6 The both ends of side plate 5.

Compacting tool set is iron and steel material quality, and with bearing capacity high, intensity is big.

The length and width scope of pressing plate 1 is 29cm -32cm, and thickness range is 10cm -15cm.

The length and width scope of base plate 3 is 48cm -50cm, and thickness range is 2cm -3cm.

The groove size of base plate 3 is identical with the base contact surface of short side plate 7, side plate long 5.

The length range of short side plate 7 is 34cm-35cm, and width range is 1.5-3cm, and altitude range is 10cm-15cm.

The length range of side plate long 5 is 43cm-45cm, and width range is 2.5-4cm, and altitude range is 10cm-15cm. Groove length scope of side plate long 5 is 1.5-3cm in it, and width range is 1.5-3cm, and altitude range is 10cm-15cm.

Double threaded screw 4 and nut 6 are corollary apparatus, play fastening side plate (side plate long 5 and short side version 7).

In the present embodiment, large-sized model compacting tool set subassembly selection is as follows：

Selection pressing plate 1 is glued board, and its length and width is 29.9cm, and thickness is 13cm；

Selection base plate 3 be iron and steel material quality, its length and width 49cm, thickness is 3cm；

Selection short side plate 7 is iron and steel material quality, and length is 34cm, and width is 2cm, is highly 10cm；

Side plate long 5 is chosen for iron and steel material quality, its length is 44cm, and width is 3cm, is highly 10cm, side plate long 5 in it Groove length is 2cm, and width is 2cm, is highly 10cm.

Large-sized model pressing process is：1. compacting tool set is prepared；2. sorting；3. stirring material；4. it is die-filling to strike-off；5. it is fixed to pressurize Shape.

2. the large-sized model that will be suppressed is put into insulating box 16, sets the heating-up temperature of insulating box 16 as 80 DEG C, warm-up time It is 40h；

3. by the large-sized model of drying drill through standard sample test permeability and porosity, and record the match is successful with actual reservoir Prepare pressure, i.e., preferred pressure.Compacting data are as follows：

The porosity of table 1 is constant, permeability variation (φ=15%)

	20	30	40
				Pressing pressure (MPa)	18	16	14

The permeability of table 2 is constant, porosity change (K=40 × 10^-3μm²)

Porosity (%)	15	10	5
				Pressing pressure (MPa)	14	16	18

(2) will determine that the back-up sand tubule of length resolves into multistage straightway, be divided into two types, the first type has been to fill out Sand tubule 8, second type is back-up sand tubule 9.Large-sized model permeability, porosity in abovementioned steps one and prepare pressure Make both back-up sand tubules；

The 37.5cm long of back-up sand tubule 8, the 25cm long of back-up sand tubule 9, two kinds of tubule external diameters are 15mm, and internal diameter is 8mm, its Making material is 316L steel.

Two kinds of back-up sand tubule manufacturing process are as follows：

1. by two kinds of straightway back-up sand tubule sample back-up sand；

Above-mentioned back-up sand tubule is fixed during actual compacting is placed on base plate 3, use natural landwaste, stone in above-mentioned steps two Sand size distribution and clay ratios and adhesive composition determine material component, rub material with the hands sand by screen filtration, uniformly Insert segmentation tubule after, using pressure testing machine, material in back-up sand tubule is pressurizeed using diameter 7.9mm pressure heads, press The pressure used by correspondence tubule sectional area is calculated according to preferred pressure in above-mentioned steps two carries out pressurization making.

By back-up sand tubule 8 according to three kinds of specifications of above-mentioned table 1, it is fabricated to that porosity is constant, three kinds of samples of permeability variation Product.According to three kinds of specifications of table 2, it is fabricated to that permeability is constant, three kinds of samples of porosity change.

By back-up sand tubule 9 according to three kinds of specifications of above-mentioned table 1, it is fabricated to that porosity is constant, three kinds of samples of permeability variation Product.According to three kinds of specifications of table 2, it is fabricated to that permeability is constant, three kinds of samples of porosity change.

2. the straightway back-up sand tubule sample that sand will be completed is put into insulating box 16 and heats drying, set the temperature of insulating box 16 as 80 DEG C, the heat time is 40h；

3. the straightway back-up sand tubule sample of drying is carried out into permeability porosity determination.Requirement is such as met according to above-mentioned step Suddenly multiple straightways are prepared again.The straightway of back-up sand tubule 8 is put into insulating box 16 and is dried, the straightway of back-up sand tubule 9 is existed The arc shape for becoming to need before material not yet solidifies has been suppressed, baking and curing in insulating box 16 has been placed into.

(3) by the foregoing two kinds of back-up sand tubules connection made, required length sum is made according to test experiments group numeral system The tubule consolidated model long of amount；

1. connection porosity is constant, and permeability variation series back-up sand tubule completes the first tubule glue long to target length Knot modelling；

, according to permeability, will successively be followed from small to large with three kinds of back-up sand tubules 8 and back-up sand tubule 9 of specification making in table 1 Ring connection is until overall length 15m；

The back-up sand tubule 8 and back-up sand tubule 9 of following permeability size are sequentially connected：

K=20 × 10^-3μm²Back-up sand tubule 8, K=30 × 10^-3μm²Back-up sand tubule 9, K=40 × 10^-3μm²Back-up sand Tubule 8, K=20 × 10^-3μm²Back-up sand tubule 9, K=30 × 10^-3μm²Back-up sand tubule 8, K=40 × 10^-3μm²Back-up sand it is thin Pipe 9；

2. connection permeability is constant, and the serial back-up sand tubule of porosity change completes second long tubule glue to target length Knot modelling.

, according to porosity, will successively be followed from small to large with three kinds of back-up sand tubules 8 and back-up sand tubule 9 of specification making in table 2 Ring connection is until overall length 15m；

The back-up sand tubule 8 and back-up sand tubule 9 of following porosity size are sequentially connected：

The back-up sand tubule 8 of φ=5%, the back-up sand tubule 9 of φ=10%, the back-up sand tubule 8 of φ=15%, φ=5% Back-up sand tubule 9, the back-up sand tubule 8 of φ=10%, the back-up sand tubule 9 of φ=15%；

(4) according to conventional fill out sand tube preparation method, common back-up sand tubule not consolidated model is made, as contrast experiment.

Step 3：Setup test CO₂- crude oil minimum miscibility pressure (MMP) experiment appliance, and connect each experimental provision；

Experiment oil：The block in-place oil.

Experiment gas：CO₂, toluene.

It is experimental provision connection figure referring to Fig. 4, slim-tube test is carried out using this experimental provision, slim-tube test device includes：

High pressure displacement pump 10, in-place oil reservoir 11, injectant hold-up vessel 12, thin tube model 13, high pressure observation window 14th, back pressure regulator 15, insulating box 16, separating bottle 17, gas gauge 18 and valve 19；

High pressure displacement pump 10 is held with in-place oil reservoir 11 in insulating box 16 with injection developing agent storage respectively by steel pipeline The valve 19 of the bottom of device 12 is connected；

In-place oil reservoir 11 is connected with steel pipeline respectively with the valve 19 at the top of injectant hold-up vessel 12, steel pipeline The other end and the arrival end of thin tube model 13 are connected；

The port of export of thin tube model 13 and valve 19 are connected, and the steel pipeline after valve 19 is adjusted through high pressure observation window 14 and back pressure Section device 15 is connected；

The afterbody of back pressure regulator 15 is connected through the separating bottle 17 outside steel pipeline and insulating box 16, the other end of separating bottle 17 warp Steel pipeline and gas gauge 18 are connected.

High pressure displacement pump 10 provides displacement power for whole experimental provision.

In-place oil reservoir 11 and injectant hold-up vessel 12 are that practice ground layer crude oil and injectant provide receiving Space.

High pressure observation window 14 provides the field of view in experimentation.

Back pressure regulator 15 ensure that the outlet of thin tube model 13 back pressure is constant.

Insulating box 16 provides temperature needed for experiment.

Separating bottle 17 is gas-liquid separation device.

The measurable gas volume of gas gauge 18.

Valve 19 controls each position pipeline closure state.

Step 4：CO is carried out using foregoing slim-tube test device₂- crude oil minimum miscibility pressure (MMP) test experiments.

According to abovementioned steps three, prepare three groups of experimental provisions, the thin tube model 13 during aforementioned means are connected respectively is changed into Made in step 2 porosity is constant and tubule consolidated model long, the length of the constant porosity change of permeability that permeability changes Tubule consolidated model and common back-up sand tubule not consolidated model (during identical experiment be referred to as thin tube model 13).

Three groups of device experimentations are identical, and every group is both needed to be repeated four times experiment by four displacement pressures, by following steps group Into：

1) saturation of in-place oil sample, obtains in-place oil saturation pressure；

Make the saturated oils of thin tube model 13 using in-place oil sample, toluene and experimental provision.

2) displacement test；Constant speed displacement test and constant pressure displacement test are carried out respectively：

(1) it is injection gas sample product are constant at 75 DEG C of experimental temperature；

(2) it is full of and is rinsed to the pipeline of the population valve of thin tube model 13 with injection gas.Injection atmospheric pressure is adjusted to experiment Pressure, records the initial reading of pump under the pressure；

(3) under 75 DEG C of experimental temperature, experimental pressure and constant note people speed, with injection gas drive in thin tube model 13 In-place oil sample, displacement velocity is 0.5ml/min.Every 20min, in each point in time measurement output oil, an air volume, The reading of record high pressure displacement pump 10, injection pressure.Note observing the phase and color change of fluid in high pressure observation window 14；

(4) after breakthrough of gas, displacement mode is changed to constant pressure displacement, a secondary data is gathered every 10min；

(5) after accumulating into 1.20 times of pore volumes of pump, displacement is stopped.

(6) thin tube model 13 is cleaned, preparation is tested next time.

3) determination of minimum miscibility pressure (MMP).

(1) 4 experimental pressures are chosen near in-place oil saturation pressure carries out slim tube driving test respectively；

(2) pressure is stepped up, displacement process is repeated；

(3) relation curve of oil displacement efficiency and displacement pressure when each slim-tube test injects 1.20 times of pore volumes is drawn Pressure corresponding to the intersection point of figure, immiscible phase section and mixed phase section curve is to be set to minimum miscibility pressure (MMP) (MMP).

The displacement pressure and recovery ratio relation obtained by experiment are as follows：

Table 3 the first tubule consolidated model experimental data long

Test number (TN)	1	2	3	4
					Displacement pressure (MPa)	10	15	20	25
Recovery ratio (%)	42	72	90.86	93

The first tubule consolidated model displacement pressure long and recovery ratio graph of a relation are obtained by data above, as shown in Figure 7； It is 18MPa to MMP values.

The second long tubule consolidated model experimental data of table 4

Test number (TN)	1	2	3	4
					Displacement pressure (MPa)	10	15	20	25
Recovery ratio (%)	38	75.14	90.75	92

Second long tubule consolidated model displacement pressure and recovery ratio graph of a relation are obtained by data above, as shown in Figure 8； It is 17MPa to MMP values.

The common back-up sand tubule of table 5 not consolidated model experimental data

Test number (TN)	1	2	3	4
					Displacement pressure (MPa)	10	15	20	25
Recovery ratio (%)	40	74.48	90.89	92.5

Common back-up sand tubule not consolidated model displacement pressure and recovery ratio graph of a relation are obtained by data above, as shown in Figure 9； MMP values are obtained for 17.25MPa.

After the present invention is implemented, combining related experimental technique with the tubule consolidated model long for providing can effectively be carried out CO₂- crude oil minimum miscibility pressure (MMP) test experiments, for the stronger directiveness of laboratory experiment provides support.

Finally it should be noted that：Various embodiments above is merely illustrative of the technical solution of the present invention, rather than its limitations；To the greatest extent Pipe has been described in detail with reference to foregoing embodiments to the present invention, it will be understood by those within the art that：Its according to The technical scheme described in foregoing embodiments can so be modified, or which part or all technical characteristic are entered Row equivalent；And these modifications or replacement, the essence of appropriate technical solution is departed from various embodiments of the present invention technology The scope of scheme, it all should cover in the middle of the scope of claim of the invention and specification.

Claims

1. CO is tested based on tubule consolidated model long₂The method of-crude oil MMP, it is characterised in that including：

Step S1, the actual reservoir data according to mining site obtains low permeability pay relevant parameter, and the parameter includes oil reservoir hole Degree, permeability and reservoir temperature；

Step S3, according to stratum crude oil sample and injection gas sample product, by the experimental provision that connects in advance to the tubule mould Type carries out saturated oils, obtains in-place oil saturation pressure；

Step S4, according to current strata pressure, chooses multiple experimental pressures, and carry out multiple tubule reality using the back-up sand tubule Test, the slim-tube test includes constant speed displacement test and constant pressure displacement test, obtain injecting 1.2 times of holes in each slim-tube test The graph of relation of oil displacement efficiency and displacement pressure during volume；

Step S5, according to the graph of relation, obtains the pressure value corresponding to the intersection point of immiscible phase section and mixed phase section curve, institute Pressure value is stated for minimum miscibility pressure (MMP) value.

2. it is according to claim 1 that CO is tested based on tubule consolidated model long₂The method of-crude oil MMP, it is characterised in that

The back-up sand tubule includes that porosity is constant, and the first back-up sand tubule that permeability changes, and permeability is constant, and porosity changes The the second back-up sand tubule for becoming.

3. it is according to claim 1 that CO is tested based on tubule consolidated model long₂The method of-crude oil MMP, it is characterised in that

The back-up sand tubule is made up of the first back-up sand tubule and second back-up sand tubule connection, the first back-up sand tubule Horizontal linear section is shaped as, second back-up sand tubule is shaped as arc.

4. it is according to claim 1 that CO is tested based on tubule consolidated model long₂The method of-crude oil MMP, it is characterised in that

In the step S4, slim-tube test is carried out using the back-up sand tubule, specially：

The pipeline of the thin tube model inlet valve for being full of and being rinsed into the experimental provision with the injection gas, by the injection gas Pressure is adjusted to the experimental pressure, records the initial reading of the experimental provision mesohigh displacement pump under the experimental pressure, institute Thin tube model is stated for the tubule consolidated model long；

Under experimental temperature, experimental pressure and constant injection rate, with the injection gas drive for the stratum in the thin tube model Crude oil sample, sets displacement velocity, determines that time of measuring is spaced, in each point in time measurement output oil, an air volume, record The reading and injection pressure of the high pressure displacement pump；

The phase and color change of fluid, after breakthrough of gas, displacement mode are changed in observation experiment device mesohigh observation window It is constant pressure displacement；

5. it is according to claim 1 that CO is tested based on tubule consolidated model long₂The method of-crude oil MMP, it is characterised in that

In the step S2, according to the low permeability pay relevant parameter, laboratory experiment tubule consolidated model long is made, and obtain To back-up sand tubule, specially：

According to the low permeability pay relevant parameter, with reference to slim-tube test national standard, the length and internal diameter of back-up sand tubule are determined；

According to the low permeability pay relevant parameter, preparation prepares the material of large-sized model and the content of every kind of material, the material Including natural landwaste, quartz sand, cement, clay；

To determine that the back-up sand tubule of length resolves into multistage straightway, it is by being segmented compacting cementing mode that the multistage is straight Line segment carries out tubule consolidated model long and makes, obtain two kinds it is cementing after thin tube model；

According to the porosity and permeability required in experiment, the connection of described two back-up sand tubules is fabricated to long needed for experiment is used The back-up sand tubule of degree and quantity.

6. CO is tested based on tubule consolidated model long₂The system of-crude oil MMP, it is characterised in that including：

Parameter acquisition module, for the actual reservoir data according to mining site, obtains low permeability pay relevant parameter, the parameter bag Include oil reservoir porosity, permeability and reservoir temperature；

Back-up sand tubule makes module, for according to the low permeability pay relevant parameter, making laboratory experiment cementing with tubule long Model, and back-up sand tubule is obtained, the tubule consolidated model long is the thin tube model for possessing micropore；

Tubule consolidated model saturated oils module long, for according to stratum crude oil sample and injection gas sample product, by connecting in advance Experimental provision carry out saturated oils to the thin tube model, obtain in-place oil saturation pressure；

Curve map generation module, for according to current strata pressure, choosing multiple experimental pressures, and is entered using the back-up sand tubule The multiple slim-tube test of row, the slim-tube test includes constant speed displacement test and constant pressure displacement test, in obtaining each slim-tube test The graph of relation of oil displacement efficiency and displacement pressure during 1.2 times of pore volumes of injection；

Minimum miscibility pressure (MMP) value acquisition module, for according to the graph of relation, obtaining immiscible phase section with mixed phase section curve Pressure value corresponding to intersection point, the pressure value is minimum miscibility pressure (MMP) value.

7. it is according to claim 6 that CO is tested based on tubule consolidated model long₂The system of-crude oil MMP, it is characterised in that

8. it is according to claim 6 that CO is tested based on tubule consolidated model long₂The system of-crude oil MMP, it is characterised in that

9. it is according to claim 6 that CO is tested based on tubule consolidated model long₂The system of-crude oil MMP, it is characterised in that

The curve map generation module, specifically for：

10. it is according to claim 6 that CO is tested based on tubule consolidated model long₂The system of-crude oil MMP, it is characterised in that

The back-up sand tubule makes module, specifically for：