CN104502237B - Device for measuring diffusion coefficient of CO2 diffusing from aqueous phase to oil phase and operating method thereof - Google Patents

Abstract

The invention relates to a device for measuring a diffusion coefficient of CO2 diffusing from an aqueous phase to an oil phase. The device comprises a CO2 gas source, a distilled water source, a U-shaped high-temperature high-pressure visual diffusion device and a crude oil source which are sequentially and vertically connected in parallel to a pipeline, wherein a steel separator is vertically arranged in the U-shaped high-temperature high-pressure visual diffusion device; the interior of the U-shaped high-temperature high-pressure visual diffusion device is separated into a left-side space and a right-side space of which the bottoms are communicated by virtue of the steel separator; a temperature measuring point, a pressure measuring point and a lower outlet are formed in the bottom in the U-shaped high-temperature high-pressure visual diffusion device; and the device also comprises a pressure collection system, a return pressure gas tank, a heater and a temperature control system. The device disclosed by the invention is reliable in principle and easy and convenient to operate, the influence caused by oil-gas-water density difference is overcome, a pressure drop method for measuring the gas-liquid two-phase diffusion coefficient is applied to measuring the diffusion coefficient of gas between the aqueous phase and oil phase, the CO2 concentration change and experimental equilibrium pressure do not need to be measured, and the diffusion coefficient of CO2 diffusing from the aqueous phase to the oil phase can be solved.

Description

A kind of measurement CO2From aqueous phase to the device of diffusion coefficient oil phase diffusion process and work thereof Make method

Technical field

The present invention relates to a kind of measurement CO₂From aqueous phase to the device of diffusion coefficient oil phase diffusion process and work side thereof Method, belongs to the technical field of petrochemical industry.

Background technology

CO₂It is to apply the most universal CO the most at present that-water alternately injects technology of reservoir sweep₂Technology of reservoir sweep.This technology is carrying High oil recovery factor aspect has good application prospect；Meanwhile, CO₂As main greenhouse gases, account for greenhouse gases total More than 2/3rds of amount, CO₂Technology of reservoir sweep is one of effective ways realizing reduction of greenhouse gas discharge.Therefore, above-mentioned technology with Its oil displacement efficiency is high, the scope of application is big, reduce the advantages such as greenhouse effect, by the extensive attention of countries in the world.

Under formation temperature, pressure, CO₂It is soluble in the aqueous phase with certain proportion and oil phase, wherein CO₂Dissolving in crude oil causes Viscosity of crude reduction, crude oil volumetric expansion, oil water interfacial tension reduction even reach mixed phase with crude oil, drastically increase CO₂ Oil displacement efficiency.In displacement process, owing to density contrast affects with differences in viscosity, CO₂Preferential above oil reservoir, height ooze band and intercommunicating pore Road passes through, and easily produces has channeling, and the crude oil in territory, bypassed area can not be with CO₂Directly contact, therefore CO₂Can only by aqueous phase to Oil phase spreads.Now study CO₂From aqueous phase to the diffusion coefficient of oil phase, Analysis for CO₂In the mass transfer Diffusion Law that profit is alternate, right In instructing CO₂Drive the raising rate of oil and gas recovery significant.

Chinese patent literature CN102706779A discloses a kind of measurement CO₂Method at diffusion coefficient of rock.With often By measuring CO in rule method₂Concentration measure CO₂Diffusion coefficient different, this invention is by measuring CO₂Gas pressure Change obtains CO₂At diffusion coefficient of rock: by the CO of correction₂The equation of gas state converses the change of its concentration, and then surveys Make CO₂Gas diffusion coefficient in rock.The defect of this patent is as follows: measure CO in this patent₂At diffusion coefficient of rock Method be for gas-liquid two-phase between coefficient of molecular diffusion for, currently for CO₂Biography between immiscible water-oil phase Matter research, particularly CO₂From aqueous phase to the mensuration of diffusion coefficient oil phase migration process, yet there are no relevant report both at home and abroad, with Time also not used for measure CO₂From aqueous phase to the relevant apparatus of oil phase migration diffusion coefficient.

The most conventional diffusion coefficients method has constant volume PVT straight tube pressure decline method, level pressure PVT straight tube pressure decline method, moves State is hung down and is dripped shape analysis method and capillary glass tube contact method etc..These method and apparatus all can only measure CO₂-crude oil system or CO₂The diffusion coefficient of-aqueous systems, there is presently no research CO₂From aqueous phase to the device of oil phase diffusion coefficient, and due to oil gas The existence of water density difference, in principle, straight tube PVT method cannot measure CO₂From aqueous phase to diffusion coefficient oil phase diffusion process.

Summary of the invention

For the deficiencies in the prior art, the invention discloses a kind of measurement CO₂Spread to oil phase diffusion process from aqueous phase The device of coefficient；

The invention also discloses the method for work of said apparatus；

It is biphase that U-shaped high-temperature high-pressure visual disperser 15 in the present invention separates oil, gas, gas phase CO₂It is first dissolved in U-shaped height In temperature high pressure visable disperser 15 in the aqueous phase of one end and bottom, then it is diffused into the diffusion of U-shaped high-temperature high-pressure visual by aqueous phase In the oil phase on device 15 other end top, keeping the saturated CO of aqueous phase₂Under premise, spread by measuring U-shaped high-temperature high-pressure visual CO in device 15₂In oil phase, dissolve the pressure change that diffusion causes, in conjunction with Fick law and mass-conservation equation, finally give CO₂From aqueous phase to diffusion coefficient oil phase diffusion process.

Term is explained

Aqueous phase, oil phase: refer to the homogeneous substance part in system with identical component, same physical chemical property, phase mutually And have obvious interface between phase, one mutually in can contain various ingredients；Due to immiscible between water and crude oil, exist substantially Oil-water interfaces, and each all can comprise various ingredients, therefore be more preferably difference crude oil and water on oil field, water is referred to as water Phase, is referred to as oil phase by crude oil.

Technical scheme is as follows:

A kind of measurement CO₂From aqueous phase to the device of diffusion coefficient oil phase diffusion process, connect including tile vertically successively CO on pipeline₂Source of the gas, distillation water source, U-shaped high-temperature high-pressure visual disperser 15, crude petroleum sources, described U-shaped High Temperature High Pressure can Depending on being vertically provided with steel body dividing plate 41 in disperser 15, described steel body dividing plate 41 is by described U-shaped high-temperature high-pressure visual disperser Leftward space 35 and rightward space 40, described U-shaped high-temperature high-pressure visual disperser 15 inner bottom that bottom communicates it is separated in 15 Portion is provided with point for measuring temperature 42, pressure tap 43, lower outlet 46, described CO₂Source of the gas, described distillation water source are respectively by described in pipeline communication Leftward space 35, described crude petroleum sources connects described rightward space 40 by described pipeline, and described device also includes pressure acquisition system System 20, back pressure gas tank 18, primary heater 13, secondary heater 23, temperature control system 44, described U-shaped high-temperature high-pressure visual Disperser 15 connects described pressure acquisition system 20, and described lower outlet 46 connects described back pressure gas tank 18 by back-pressure valve 17, It is provided with described CO in described primary heater 13₂Source of the gas and described distillation water source, arranged in described secondary heater 23 State crude petroleum sources, bottom described U-shaped high-temperature high-pressure visual disperser 15, be provided with temperature control system 44.

Described CO₂Source of the gas provides CO for described U-shaped high-temperature high-pressure visual disperser 15₂；Described distillation water source is described U Type high-temperature high-pressure visual disperser 15 provides distilled water；Described crude petroleum sources is described U-shaped high-temperature high-pressure visual disperser 15 Crude oil is provided；Described pressure acquisition system 20 is used for storing, show described U-shaped high-temperature high-pressure visual disperser 15 in pressure, Temperature data；Described primary heater 13 is for described CO₂Source of the gas and described distillation water source carry out heating and thermal insulation；Described second Heater 23 is for carrying out heating and thermal insulation to described crude petroleum sources；Described back pressure gas tank 18 is used for as described U-shaped high-temperature high-pressure visual Disperser 15 provides back pressure；Described temperature control system 44 is used for heating described U-shaped high-temperature high-pressure visual disperser 15.

According to currently preferred, bottom described U-shaped high-temperature high-pressure visual disperser 15, it is provided with base 45, described base 45 are provided with described temperature control system 44.

According to currently preferred, described U-shaped high-temperature high-pressure visual disperser 15 both sides are provided with the visual glass of pressure-bearing 36 And stainless corrosion-resistant steel body 29, by bolt 30, visual for described pressure-bearing glass 36 is embedded in described stainless corrosion-resistant steel body 29, described Middle pressure pad 32, O 33, upper pressure pad 34 seal the ring between the visual glass of described pressure-bearing 36 and described stainless corrosion-resistant steel body 29 Shape gap；Described stainless corrosion-resistant steel body 29 heatproof is 150 DEG C, pressure for 32MPa；Described middle pressure pad 32, O 33, upper pressure Pad 34 pressure for 25MPa.

The advantage herein designed is, can observe diffusion process by the visual glass of described pressure-bearing 36 objective reality Level change, and read oil phase, gas phase height.

According to currently preferred, described U-shaped high-temperature high-pressure visual disperser 15 top is provided with rotary gland 31.

The advantage herein designed is, rotary gland 31 can be dismantled, and facilitates experiment to clean described U-shaped high temperature after terminating high Press visual disperser 15 inner space.

According to currently preferred, described CO₂Source of the gas includes CO₂Gas tank 7 and the first constant-flux pump 3, described distillation water source includes Distillation water pot 8 and described first constant-flux pump 3, described crude petroleum sources includes petroleum tank 21 and the second constant-flux pump 24, described CO₂Gas tank 7 Interior axial direction is provided with piston, and the axial direction in described distillation water pot 8 is provided with piston, and the axial direction in described petroleum tank 21 is provided with Piston, described CO₂Gas tank 7 bottom connects needle-valve 5, and described distillation water pot 8 bottom connects needle-valve 6, described U-shaped high-temperature high-pressure visual Disperser 15 bottom connects needle-valve 16, and described petroleum tank 21 bottom connects needle-valve 22, and described first constant-flux pump 3 passes through three-way valve 4 connect described needle-valve 5, described needle-valve 6 respectively, and described back pressure gas tank 18 connects described needle-valve 16, institute by described back-pressure valve 17 State the second constant-flux pump 24 and connect described petroleum tank 21 by described needle-valve 22.

Described first constant-flux pump 3 is used for as described CO₂CO in gas tank 7₂And the distilled water in described distillation water pot 8 pumps into Described U-shaped high-temperature high-pressure visual disperser 15 provides power；Described second constant-flux pump 24 is the crude oil in described petroleum tank 21 Pump into described U-shaped high-temperature high-pressure visual disperser 15 and power is provided.

According to currently preferred, described device also includes vacuum pump 1, and described vacuum pump 1 top connects needle-valve 2, described CO₂Gas tank 7 top connects needle-valve 9, and described distillation water pot 8 top connects needle-valve 10, and described leftward space 35 top connects needle-valve 14, described rightward space 40 top connects needle-valve 19, and described pipeline is sequentially connected with three-way valve 11, three-way valve 12, described threeway The gas outlet of valve 11 is connected with described needle-valve 2, described needle-valve 9, described three-way valve 12 respectively, and the gas outlet of described three-way valve 12 is divided Not being connected with described three-way valve 11, described needle-valve 10, described needle-valve 14, described petroleum tank 21 connects described by described needle-valve 19 U-shaped high-temperature high-pressure visual disperser 15.

Described vacuum pump 1 be used for testing before to described CO₂Gas tank 7 and described distillation water pot 8 carry out application of vacuum.

According to currently preferred, described leftward space 35 top is provided with standby import and export 26, in described rightward space 40 Portion is provided with standby import and export 27, and described pressure acquisition system 20 connects described standby import and export 26 and described respectively by three-way valve Standby import and export 27.

According to currently preferred, described leftward space 35 top is additionally provided with CO₂Import 25, described rightward space 40 top Being additionally provided with crude oil import 28, described needle-valve 14 is by described CO₂Import 25 connects described U-shaped high-temperature high-pressure visual disperser 15, described needle-valve 19 connects described U-shaped high-temperature high-pressure visual disperser 15 by described crude oil import 28.

The method of work of said apparatus, concrete steps include:

(1) air-tightness of whole device is checked；

(2) utilize described vacuum pump 1 by described CO₂Gas tank 7, described distillation water pot 8 and described U-shaped high-temperature high-pressure visual expand In bulk put 15 evacuation；

(3) by CO₂, distilled water and crude oil proceed to described CO respectively₂Gas tank 7, described distillation water pot 8 and described petroleum tank 21 In, utilize described primary heater 13 by described CO₂Gas tank 7 and described distillation water pot 8 are heated up to experimental temperature T, utilize described Described petroleum tank 21 is heated up to experimental temperature T by secondary heater 23, and the span of described T is 25 DEG C-90 DEG C, stand-by；

(4) utilize described temperature control system 44 that described U-shaped high-temperature high-pressure visual disperser 15 is heated to experiment temperature Degree T；

(5) open described needle-valve 6, described needle-valve 10 and described needle-valve 14, utilize described first constant-flux pump 3 by described distillation Distilled water in water pot 8 pumps in described U-shaped high-temperature high-pressure visual disperser 15, makes distilled water be full of described U-shaped high temperature high Pressing visual disperser 15, and be pressurized to predetermined pressure P1, the span of described P1 is 0.1MPa-25MPa；

(6) adjusting the pressure in described back pressure gas tank 18 to P2, described P2 is (P1-0.1) MPa；

(7) close described needle-valve 6 and described needle-valve 10, open described needle-valve 5, described needle-valve 9 and described needle-valve 16, connect Back pressure, under constant-pressure conditions, utilizes described first constant-flux pump 3 by described CO₂CO in gas tank 7₂Deliver to described U-shaped High Temperature High Pressure In the described leftward space 35 of visual disperser 15, and CO₂Do not arrive described rightward space 40, close the first constant-flux pump 3；

Due to the existence of back pressure P2, described in step (7), U-shaped intrinsic pressure the trying hard to keep of high-temperature high-pressure visual disperser 15 is held not Becoming, described back-pressure valve 17 exit has distilled water to discharge, and the distilled water of discharge and step (7) enter described U-shaped High Temperature High Pressure can Depending on the CO in disperser 15₂Equal-volume；

(8) described needle-valve 5, described needle-valve 9 and described needle-valve 16 are closed, described U-shaped high-temperature high-pressure visual disperser 15 Close, utilize described pressure acquisition system 20 to observe the pressure change that described pressure tap measures, until pressure declines width in 30min Degree is less than till 1KPa, and the fluid in described U-shaped high-temperature high-pressure visual disperser 15 is in dynamic balance state, in water CO₂Reaching saturated, form saturated carbon sour water, the pressure recorded in the most described high-temperature high-pressure visual disperser 15 is reality Test initial pressure P3；

(9) adjusting the pressure in described back pressure gas tank 18 to P4, described P4 is (P3-0.1) MP；

(10) open described needle-valve 16, described needle-valve 19 and described needle-valve 22, connect back pressure, under constant-pressure conditions, utilize The described right side of described U-shaped high-temperature high-pressure visual disperser 15 delivered to by crude oil in described petroleum tank 21 by the second constant-flux pump 24 In space 40, and crude oil does not arrive described leftward space 35, closes the second constant-flux pump 24, by the visual glass of described pressure-bearing 36 observe and record the crude oil height z in described rightward space 40₀；

Due to the existence of back pressure P4, described in step (10), U-shaped intrinsic pressure the trying hard to keep of high-temperature high-pressure visual disperser 15 is held not Becoming, described back-pressure valve 17 exit has distilled water to discharge, and the distilled water of discharge and step (10) deliver to described U-shaped High Temperature High Pressure can Depending on the crude oil equal-volume in disperser 15；

(11) described needle-valve 16, described needle-valve 19 and described needle-valve 22 are closed, described U-shaped high-temperature high-pressure visual disperser 15 close, and utilize described pressure acquisition system 20 to observe pressure P (t) change that pressure tap described in t the most in the same time measures, record pressure Power P (t)-time t relation data, in 30min, pressure fall is less than till 1KPa, records the most described U-shaped height Pressure in temperature high pressure visable disperser 15 is experiment final balance pressure P_eq；

(12) pressure P (the t)-time t relation data of step (11) described pressure acquisition system 20 record according to the following formula Carry out nonlinear fitting:

$P\left(t\right)=m_1{e}^{(-\frac{t}{k_1})}+m_2{e}^{(-\frac{t}{k_2})}+{P_{\mathrm{eq}}}^{\′}---\left(I\right)$

In formula I, P (t) is the force value recording t, and unit is Pa；P_eq' flat for the theory of nonlinear regression acquisition Weighing apparatus force value, unit is Pa；m₁,m₂,k₁,k₂For based on the parameter that experimental data nonlinear regression is obtained；T is diffusion time, Unit is s；

Pressure P (t) in formula I and time t are it is known that draw m by nonlinear fitting₁,m₂,k₁,k₂And P_eq' theory Value；

(13) according to following formula:

$D_{\mathrm{ab}}=\frac{4{z_o}^2}{k_1{\mathrm{\π}}^2}---\left(\mathrm{II}\right)$

In formula II, D_abFor CO₂From aqueous phase to the diffusion coefficient of oil phase, unit is m²/s；z_oThe institute recorded for step (10) Stating crude oil height in U-shaped high-temperature high-pressure visual disperser 15, unit is m；

Parameter k that step (12) is tried to achieve₁Substitute in formula II, obtain CO₂Migrate diffusion coefficient D to oil phase from aqueous phase_ab。

Described formula I and described formula II are shown in that the pressure decline method that improves of the foundation such as Zhang surveys gas diffusion system in viscous crude Digital-to-analogue type, concrete derivation is as follows:

According to Fick's law, gas diffusion flux in the liquid phase is as follows:

$\frac{{\mathrm{dx}}_1}{\mathrm{dt}}+v*\frac{{\mathrm{dx}}_1}{\mathrm{dz}}=D_{\mathrm{ab}}\frac{d^2{x}_1}{{\mathrm{dz}}^2}---\left(\mathrm{III}\right)$

In formula III, x₁For the molar concentration of gas, unit is mol/L；V* is a mole Mean Speed；Z is along diffusion barrel Change in location, unit is m；

Finally decline the stage reaching balance at pressure, pressure only changes over, unrelated with position, therefore:

$\frac{\mathrm{dp}}{\mathrm{dz}}=0---\left(\mathrm{IV}\right)$

In formula III, oil phase keeps constant in diffusion process, and mole Mean Speed v* is 0, and therefore, diffusion process simplifies For one-dimensional and unsteady state diffusion equation:

$\frac{{\mathrm{dx}}_1}{\mathrm{dt}}=D_{\mathrm{ab}}\frac{d^2{x}_1}{{\mathrm{dz}}^2}---\left(V\right)$

Boundary condition and initial condition be:

Z=z₀, t ＞ 0, x₁=x_1,eq (Ⅵ)

$z=0,\frac{{\mathrm{dx}}_1}{\mathrm{dz}}=0---\left(\mathrm{VII}\right)$

0≤z≤z₀, t=0, x₁=0 (VIII)

In formula VI, x_1,eqFor the gas phase molar concentration between a certain special time gas-liquid interface；

In liquid phase, the initial molar concentration of gas phase is 0, x_1,eqChange along with pressure, temperature variation, owing to experiment is perseverance Temperature condition, so x_1,eqOnly changing with pressure, formula V regards the function (Crank, 1995) that molar concentration is time and position as；

$x_1=x_{1,\mathrm{eq}}-\frac{{4x}_{1,\mathrm{eq}}}{\mathrm{\π}}\underset{n=0}{\overset{\∞}{\mathrm{\Σ}}}\frac{{(-1)}^n}{2n+1}\×\cos \left(\frac{(2n+1)\mathrm{\πz}}{{2z}_0}\right)\×\exp (-\frac{{(2n+1)}^2{\mathrm{\π}}^2{D}_{\mathrm{ab}}}{{{4z}_0}^2}t)---\left(\mathrm{IX}\right)$

In addition, the number of moles of gas reduced in gas phase should be equal to the number of moles of gas at gas-liquid interface, therefore, Obtain following material balance equation:

$\frac{V}{Z_g\mathrm{RT}}\frac{\mathrm{dP}\left(t\right)}{\mathrm{dt}}=-D_{\mathrm{ab}}A{\left(\frac{{\mathrm{dx}}_1}{\mathrm{dz}}\right)}_{z=z_0}---\left(X\right)$

In formula (Ⅹ), V is gaseous phase volume, and unit is m³；R is gas constant, R=8.314m³·Pa·K^-1·mol^-1；T For temperature, unit is K；Z_gFor the carbon dioxide compression factor；

Because gas volume and sectional area keep constant, formula (Ⅹ) be reduced to:

$\frac{\mathrm{dP}\left(t\right)}{\mathrm{dt}}=-\frac{Z_g\mathrm{RT}}{h}{D}_{\mathrm{ab}}{\left(\frac{{\mathrm{dx}}_1}{\mathrm{dz}}\right)}_{z=z_0}---\left(\mathrm{XI}\right)$

Owing to the change of diffusion process pressure is little, therefore coefficient of compressibility Z_gConstant it is considered as in diffusion process；

Formula (Ⅺ) to the time from t to infinitely great integration, obtain:

$\underset{P\left(t\right)}{\overset{P_{\mathrm{eq}}}{\∫}}\mathrm{dP}\left(t\right)=-B{D}_{\mathrm{ab}}\underset{t}{\overset{\∞}{\∫}}{\left(\frac{{\mathrm{dx}}_1}{\mathrm{dz}}\right)}_{z=z_0}\mathrm{dt}---\left(\mathrm{XII}\right)$

HereBeing a constant, h is gas phase height, and unit is m；

Formula (Ⅸ) carries out differential to z, obtains z=z₀Time:

${\left(\frac{{\mathrm{dx}}_1}{\mathrm{dz}}\right)}_{z=z_0}=\frac{{2x}_{1,\mathrm{eq}}}{z_o}\underset{n=0}{\overset{\∞}{\mathrm{\Σ}}}(-\frac{{(2n+1)}^2{\mathrm{\π}}^2{D}_{\mathrm{ab}}}{{{4z}_0}^2}t)---\left(\mathrm{XIII}\right)$

Formula (XIII) is substituted into formula (Ⅻ) integration, obtains:

$P\left(t\right)-P_{\mathrm{eq}}=\frac{{8B{z}_{o}x}_{1,\mathrm{eq}}}{{\mathrm{\π}}^2}\underset{n=0}{\overset{\∞}{\mathrm{\Σ}}}\frac{1}{{(2n+1)}^2}\×\exp (-\frac{{(2n+1)}^2{\mathrm{\π}}^2{D}_{\mathrm{ab}}}{{{4z}_0}^2}t)---\left(\mathrm{XIV}\right)$

In formula (XIV), P (t) is surveyed test pressure by t, and unit is Pa；P_eqFor reaching experimental equilibrium pressure during balance Power, unit is Pa；

Formula (XIV) is arranged, omits back item, retain Section 1, and take the logarithm, finally give pressure and time it Between relation:

$\mathrm{Ln}(P\left(t\right)-P_{\mathrm{eq}})=\mathrm{Ln}\left(\frac{{8B{z}_{o}x}_{1,\mathrm{eq}}}{{\mathrm{\π}}^2}\right)-\frac{{\mathrm{\π}}^2{D}_{\mathrm{ab}}}{{{4z}_o}^2}t---\left(\mathrm{XV}\right)$

Formula (XV) finds out that pressure reduction logarithm is linear with the time, and slope is

Ask for diffusion coefficient D_abAnother mode be numerical fitting analytic expression, this method with solving of Formula X IV is Consistent；Formula (XIV) is write as:

$P\left(t\right)=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{m}_1{e}^{(-\frac{t}{k_1})}+{P_{\mathrm{eq}}}^{\′}---\left(\mathrm{XVI}\right)$

Formula (XVI) takes front two expansion, i.e. can get foregoing formula I.

Formula I and formula (XV) are contrasted, can obtain:

$-\frac{{\mathrm{\π}}^2{D}_{\mathrm{ab}}}{{{4z}_o}^2}t=-\frac{t}{k_1}---\left(\mathrm{XVII}\right)$

Abbreviation formula (XVII), finally can obtain described CO₂From aqueous phase to oil phase migration diffusion coefficient calculating formula II:

$D_{\mathrm{ab}}=\frac{4{z_o}^2}{k_1{\mathrm{\π}}^2}.$

The operation principle of the present invention is:

Described U-shaped high-temperature high-pressure visual disperser 15 separates oil phase, gas phase, the CO in gas phase₂It is first dissolved in described U-shaped In high-temperature high-pressure visual disperser 15 bottom aqueous phase, then it is diffused into described U-shaped high-temperature high-pressure visual disperser by aqueous phase In 15 other end oil phases, it is assumed that the most saturated CO of carbonated water bottom diffusion process₂, by measuring CO₂Spread in saturated carbon sour water The pressure change caused, thus indirectly obtain CO₂From aqueous phase to the diffusion coefficient oil phase diffusion process.

The invention have the benefit that

Instant invention overcomes the impact that oil gas water density difference causes, should by the pressure decline method measuring gas-liquid two-phase diffusion coefficient Use gas between aqueous phase, oil phase in diffusion coefficients, it is not necessary to measure CO₂Concentration change and experimental equilibrium pressure can be obtained CO₂From aqueous phase to the diffusion coefficient of oil phase；The liquid of diffusion process can be observed by the visual glass of described pressure-bearing objective reality Face changes, and reads oil phase, gas phase height；Heater realizes the mensuration of diffusion coefficient under High Temperature High Pressure.Therefore, required CO₂From Aqueous phase diffusion coefficient in oil phase diffusion process can relatively accurately reflect CO₂From aqueous phase to the diffusion process of oil phase.

Accompanying drawing explanation

Fig. 1 is the structural representation of the present invention；

Fig. 2 is the structural representation of described U-shaped high-temperature high-pressure visual disperser；

Fig. 3 is the side view of described U-shaped high-temperature high-pressure visual disperser；

Pressure vs time that according to Fig. 4, described pressure P (t)-time t relation data obtains and fitting result figure；

Wherein, 1, vacuum pump；2, needle-valve；3, the first constant-flux pump；4, three-way valve；5, needle-valve；6, needle-valve；7、CO₂Gas tank；8、 Distillation water pot；9, needle-valve；10, needle-valve；11, three-way valve；12, three-way valve；13, primary heater；14, needle-valve；15, U-shaped high temperature High pressure visable disperser；16, needle-valve；17, back-pressure valve；18, back pressure gas tank；19, needle-valve；20, pressure acquisition system；21, former Oil tank；22, needle-valve；23, secondary heater；24, the second constant-flux pump；25、CO₂Import；26, standby import and export；27, standby turnover Mouthful；28, crude oil import；29, stainless corrosion-resistant steel body；30, bolt；31, rotary gland；32, middle pressure pad；33, O；34, on Pressure pad；35, leftward space；36, the visual glass of pressure-bearing；37, bottom space；38, gas-water interface；39, oil-water interfaces；40, right side Space；41, steel body interlayer；42, point for measuring temperature；43, pressure tap；44, temperature control system；45, base；46, lower outlet.

Detailed description of the invention

Below according to embodiment and Figure of description, the present invention is described in detail, but is not limited to this.

Embodiment 1

A kind of measurement CO₂From aqueous phase to the device of diffusion coefficient oil phase diffusion process, connect including tile vertically successively CO on pipeline₂Source of the gas, distillation water source, U-shaped high-temperature high-pressure visual disperser 15, crude petroleum sources, described U-shaped High Temperature High Pressure can Depending on being vertically provided with steel body dividing plate 41 in disperser 15, described steel body dividing plate 41 is by described U-shaped high-temperature high-pressure visual disperser Leftward space 35 and rightward space 40, described U-shaped high-temperature high-pressure visual disperser 15 inner bottom that bottom communicates it is separated in 15 Portion is provided with point for measuring temperature 42, pressure tap 43, lower outlet 46, described CO₂Source of the gas, described distillation water source are respectively by described in pipeline communication Leftward space 35, described crude petroleum sources connects described rightward space 40 by described pipeline, and described device also includes pressure acquisition system System 20, back pressure gas tank 18, primary heater 13, secondary heater 23, temperature control system 44, described U-shaped high-temperature high-pressure visual Disperser 15 connects described pressure acquisition system 20, and described lower outlet 46 connects described back pressure gas tank 18 by back-pressure valve 17, It is provided with described CO in described primary heater 13₂Source of the gas and described distillation water source, arranged in described secondary heater 23 State crude petroleum sources, bottom described U-shaped high-temperature high-pressure visual disperser 15, be provided with temperature control system 44.

Described CO₂Source of the gas provides CO for described U-shaped high-temperature high-pressure visual disperser 15₂；Described distillation water source is described U Type high-temperature high-pressure visual disperser 15 provides distilled water；Described crude petroleum sources is described U-shaped high-temperature high-pressure visual disperser 15 Crude oil is provided；Described pressure acquisition system 20 is used for storing, show described U-shaped high-temperature high-pressure visual disperser 15 in pressure, Temperature data；Described primary heater 13 is for described CO₂Source of the gas and described distillation water source carry out heating and thermal insulation；Described second Heater 23 is for carrying out heating and thermal insulation to described crude petroleum sources；Described back pressure gas tank 18 is used for as described U-shaped high-temperature high-pressure visual Disperser 15 provides back pressure；Described temperature control system 44 is used for heating described U-shaped high-temperature high-pressure visual disperser 15.

Embodiment 2

According to device described in embodiment 1, its difference is, is provided with bottom described U-shaped high-temperature high-pressure visual disperser 15 Base 45, described base 45 is provided with described temperature control system 44.

Embodiment 3

According to device described in embodiment 1 or 2, its difference is, described U-shaped high-temperature high-pressure visual disperser 15 both sides set There are the visual glass of pressure-bearing 36 and stainless corrosion-resistant steel body 29, visual for described pressure-bearing glass 36 embedded described stainless resistance to by bolt 30 In erosion steel body 29, described middle pressure pad 32, O 33, that upper pressure pad 34 seals the visual glass of described pressure-bearing 36 is stainless resistance to described Annular gap between erosion steel body 29；Described stainless corrosion-resistant steel body 29 heatproof is 150 DEG C, pressure for 32MPa；Described middle pressure pad 32, O 33, upper pressure pad 34 is pressure for 25MPa.

The advantage herein designed is, can observe diffusion process by the visual glass of described pressure-bearing 36 objective reality Level change, and read oil phase, gas phase height.

Embodiment 4

According to device described in embodiment 3, its difference is, described U-shaped high-temperature high-pressure visual disperser 15 top is provided with Rotary gland 31.

The advantage herein designed is, rotary gland 31 can be dismantled, and facilitates experiment to clean described U-shaped high temperature after terminating high Press visual disperser 15 inner space.

Embodiment 5

According to device described in embodiment 4, its difference is, described CO₂Source of the gas includes CO₂Gas tank 7 and the first constant-flux pump 3, institute Stating distillation water source to include distilling water pot 8 and the first constant-flux pump 3, described crude petroleum sources includes petroleum tank 21 and the second constant-flux pump 24, institute State CO₂Axial direction in gas tank 7 is provided with piston, and the axial direction in described distillation water pot 8 is provided with piston, in described petroleum tank 21 Axially it is provided with piston, described CO₂Gas tank 7 bottom connects needle-valve 5, and described distillation water pot 8 bottom connects needle-valve 6, described U-shaped height Temperature high pressure visable disperser 15 bottom connects needle-valve 16, and described petroleum tank 21 bottom connects needle-valve 22, described first constant-flux pump 3 Connecting described needle-valve 5, described needle-valve 6 respectively by three-way valve 4, described back pressure gas tank 18 connects described by described back-pressure valve 17 Needle-valve 16, described second constant-flux pump 24 connects described petroleum tank 21 by described needle-valve 22.

Described first constant-flux pump 3 is used for as described CO₂CO in gas tank 7₂And the distilled water in described distillation water pot 8 pumps into Described U-shaped high-temperature high-pressure visual disperser 15 provides power；Described second constant-flux pump 24 is the crude oil in described petroleum tank 21 Pump into described U-shaped high-temperature high-pressure visual disperser 15 and power is provided.

Embodiment 6

According to device described in embodiment 5, its difference is, described device also includes vacuum pump 1, described vacuum pump 1 top Connect needle-valve 2, described CO₂Gas tank 7 top connects needle-valve 9, and described distillation water pot 8 top connects needle-valve 10, described leftward space 35 tops connect needle-valve 14, and described rightward space 40 top connects needle-valve 19, and described pipeline is sequentially connected with three-way valve 11, threeway Valve 12, the gas outlet of described three-way valve 11 is connected with described needle-valve 2, described needle-valve 9, described three-way valve 12 respectively, described threeway The gas outlet of valve 12 is connected with described three-way valve 11, described needle-valve 10, described needle-valve 14 respectively, and described petroleum tank 21 is by described Needle-valve 19 connects described U-shaped high-temperature high-pressure visual disperser 15.

Described vacuum pump 1 be used for testing before to described CO₂Gas tank 7 and described distillation water pot 8 carry out application of vacuum.

Embodiment 7

According to device described in embodiment 6, its difference is, described leftward space 35 top is provided with standby import and export 26, institute Stating rightward space 40 top and be provided with standby import and export 27, described pressure acquisition system 20 connects described standby by three-way valve respectively Import and export 26 and described standby import and export 27.

Embodiment 8

According to device described in embodiment 7, its difference is, described leftward space 35 top is additionally provided with CO₂Import 25, described Rightward space 40 top is additionally provided with crude oil import 28, and described needle-valve 14 is by described CO₂Import 25 connects described U-shaped High Temperature High Pressure Visual disperser 15, described needle-valve 19 connects described U-shaped high-temperature high-pressure visual disperser 15 by described crude oil import 28.

Embodiment 9

According to the method for work of device described in embodiment 6, concrete steps include:

(1) air-tightness of whole device is checked；

(2) utilize described vacuum pump 1 by described CO₂Gas tank 7, described distillation water pot 8 and described U-shaped high-temperature high-pressure visual expand In bulk put 15 evacuation；

(3) by CO₂, distilled water and crude oil proceed to described CO respectively₂Gas tank 7, described distillation water pot 8 and described petroleum tank 21 In, utilize described primary heater 13 by described CO₂Gas tank 7 and described distillation water pot 8 are heated up to experimental temperature 40 DEG C, utilize institute State secondary heater 23 and described petroleum tank 21 is heated up to experimental temperature 40 DEG C, stand-by；

(4) utilize described temperature control system 44 that described U-shaped high-temperature high-pressure visual disperser 15 is heated to experiment temperature Spend 40 DEG C；

(5) open described needle-valve 6, described needle-valve 10 and described needle-valve 14, utilize described first constant-flux pump 3 by described distillation Distilled water in water pot 8 pumps in described U-shaped high-temperature high-pressure visual disperser 15, makes distilled water be full of described U-shaped high temperature high Pressing visual disperser, and be pressurized to predetermined pressure P1, the value of described P1 is 12MPa；

(6) adjusting the pressure in described back pressure gas tank 18 to P2, described P2 is 11.9MPa；

(7) close described needle-valve 6 and described needle-valve 10, open described needle-valve 5, described needle-valve 9 and described needle-valve 16, connect Logical back pressure, under constant-pressure conditions, utilizes described first constant-flux pump 3 by described CO₂CO in gas tank 7₂Deliver to described U-shaped high temperature high Press in the described leftward space 35 of visual disperser 15, and CO₂Do not arrive described rightward space 40, close the first advection Pump 3；

Due to the existence of back pressure P2, described in step (7), U-shaped intrinsic pressure the trying hard to keep of high-temperature high-pressure visual disperser 15 is held not Becoming, described back-pressure valve 17 exit has distilled water to discharge, and the distilled water of discharge and step (7) enter described U-shaped High Temperature High Pressure can Depending on the CO in disperser 15₂Equal-volume；

(8) described needle-valve 5, described needle-valve 9 and described needle-valve 16 are closed, described U-shaped high-temperature high-pressure visual disperser 15 Close, utilize described pressure acquisition system 20 to observe the pressure change that described pressure tap measures, until pressure declines width in 30min Degree is less than till 1KPa, and the fluid in described U-shaped high-temperature high-pressure visual disperser 15 is in dynamic balance state, in water CO₂Reach saturated, form saturated carbon sour water, record the pressure 9.86MPa in the most described high-temperature high-pressure visual disperser 15 It is experiment initial pressure P3；

(9) adjusting the pressure in described back pressure gas tank 18 to P4, described P4 is 9.76MPa；

(10) open described needle-valve 16, described needle-valve 19 and described needle-valve 22, connect back pressure, under constant-pressure conditions, utilize Crude oil in described petroleum tank 21 is delivered to the diffusion of described U-shaped high-temperature high-pressure visual with the speed of 10mL/min by the second constant-flux pump 24 In the described rightward space 40 of device 15, and crude oil does not arrive described leftward space 35, closes the second constant-flux pump 24, passes through The crude oil height in described rightward space 40 is observed and recorded to the visual glass of described pressure-bearing 36 is 0.04m；

Due to the existence of back pressure P4, described in step (10), U-shaped intrinsic pressure the trying hard to keep of high-temperature high-pressure visual disperser 15 is held not Becoming, described back-pressure valve 17 exit has distilled water to discharge, and the distilled water of discharge and step (10) deliver to described U-shaped High Temperature High Pressure can Depending on the crude oil equal-volume in disperser 15；

(11) described needle-valve 16, described needle-valve 19 and described needle-valve 22 are closed, described U-shaped high-temperature high-pressure visual disperser 15 close, and utilize described pressure acquisition system 20 to observe pressure P (t) change that pressure tap described in t the most in the same time measures, record pressure Power P (t)-time t relation data, in 30min, pressure fall is less than till 1KPa, records the most described U-shaped height Pressure 9.658MPa in temperature high pressure visable disperser 15 is experiment final balance pressure P_eq；

(12) pressure P (the t)-time t relation data of step (11) described pressure acquisition system 20 record according to the following formula Carry out nonlinear fitting:

$P\left(t\right)=m_1{e}^{(-\frac{t}{k_1})}+m_2{e}^{(-\frac{t}{k_2})}+{P_{\mathrm{eq}}}^{\′}---\left(I\right)$

In formula I, P (t) is the force value recording t, and unit is Pa；P_eq' flat for the theory of nonlinear regression acquisition Weighing apparatus force value, unit is Pa；m₁,m₂,k₁,k₂For based on the parameter that experimental data nonlinear regression is obtained；T is diffusion time, Unit is s；

Pressure P (t) in formula I and time t are it is known that draw m by nonlinear fitting₁,m₂,k₁,k₂And P_eq' theory Value as shown in Figure 4, tries to achieve k₁=32190；

(13) according to following formula:

$D_{\mathrm{ab}}=\frac{4{z_o}^2}{k_1{\mathrm{\π}}^2}---\left(\mathrm{II}\right)$

In formula II, D_abFor CO₂From aqueous phase to the diffusion coefficient of oil phase, unit is m²/s；z_oThe institute recorded for step (10) State the height of oil phase in U-shaped high-temperature high-pressure visual disperser 15, it is known that z_o=0.04m；

Parameter k that step (12) is tried to achieve₁Substitute in formula II, obtain CO₂From aqueous phase to the diffusion system oil phase diffusion process Number:

$D_{\mathrm{ab}}=\frac{4{z_o}^2}{k_1{\mathrm{\π}}^2}=\frac{4\×0.04\×0.04}{32190\×3.14\×3.14}=2.02\×{10}^{-8}{m}^2/s.$

Table 1 is the pressure vs time table obtained according to pressure P (t)-time t relation data, as follows:

Table 1

Claims (9)

1. measure CO for one kind₂From aqueous phase to the device of diffusion coefficient oil phase diffusion process, it is characterised in that include the most vertical It is connected to the CO on pipeline side by side₂Source of the gas, distillation water source, U-shaped high-temperature high-pressure visual disperser (15), crude petroleum sources, described U-shaped Vertically being provided with steel body dividing plate (41) in high-temperature high-pressure visual disperser (15), described steel body dividing plate (41) is by described U-shaped high temperature Leftward space (35) and rightward space (40), described U-shaped high temperature that bottom communicates it is separated in high pressure visable disperser (15) High pressure visable disperser (15) inner bottom part is provided with point for measuring temperature (42), pressure tap (43), lower outlet (46), described CO₂Source of the gas, institute Stating distillation water source respectively by leftward space (35) described in pipeline communication, described crude petroleum sources connects described right side by described pipeline Space (40), described device also includes pressure acquisition system (20), back pressure gas tank (18), primary heater (13), the second heating Device (23), temperature control system (44), described U-shaped high-temperature high-pressure visual disperser (15) connects described pressure acquisition system (20), described lower outlet (46) connects described back pressure gas tank (18) by back-pressure valve (17), and described primary heater sets in (13) It is equipped with described CO₂Source of the gas and described distillation water source, be provided with described crude petroleum sources, described U-shaped height in described secondary heater (23) Temperature high pressure visable disperser (15) bottom is provided with temperature control system (44).

Device the most according to claim 1, it is characterised in that described U-shaped high-temperature high-pressure visual disperser (15) bottom sets Base (45), described base (45) is had to be provided with described temperature control system (44).

Device the most according to claim 1, it is characterised in that described U-shaped high-temperature high-pressure visual disperser (15) both sides set There are the visual glass of pressure-bearing (36) and stainless corrosion-resistant steel body (29), by bolt (30), visual for described pressure-bearing glass (36) embedded institute Stating in stainless corrosion-resistant steel body (29), middle pressure pad (32), O (33), upper pressure pad (34) seal the visual glass of described pressure-bearing (36) annular gap and between described stainless corrosion-resistant steel body (29)；Described stainless corrosion-resistant steel body (29) heatproof is 150 DEG C, pressure For 32MPa；Described middle pressure pad (32), O (33), upper pressure pad (34) is pressure for 25MPa.

Device the most according to claim 1, it is characterised in that described U-shaped high-temperature high-pressure visual disperser (15) top sets There is rotary gland (31).

Device the most according to claim 1, it is characterised in that described CO₂Source of the gas includes CO₂Gas tank (7) and the first constant-flux pump (3), described distillation water source includes distilling water pot (8) and the first constant-flux pump (3), and described crude petroleum sources includes petroleum tank (21) and second Constant-flux pump (24), described CO₂Axial direction in gas tank (7) is provided with piston, and the axial direction in described distillation water pot (8) is provided with work Plug, the axial direction in described petroleum tank (21) is provided with piston, described CO₂Gas tank (7) bottom connects needle-valve II (5), described distillation Water pot (8) bottom connects needle-valve III (6), and described U-shaped high-temperature high-pressure visual disperser (15) bottom connects needle-valve VII (16), Described petroleum tank (21) bottom connects needle-valve Ⅸ (22), and described first constant-flux pump (3) connects described respectively by three-way valve I (4) Needle-valve II (5), described needle-valve III (6), described back pressure gas tank (18) connects described needle-valve VII by described back-pressure valve (17) (16), described second constant-flux pump (24) connects described petroleum tank (21) by described needle-valve Ⅸ (22).

Device the most according to claim 5, it is characterised in that described device also includes vacuum pump (1), described vacuum pump (1) Top connects needle-valve I (2), described CO₂Gas tank (7) top connects needle-valve IV (9), and described distillation water pot (8) top connects needle-valve V (10), described leftward space (35) top connects needle-valve VI (14), and described rightward space (40) top connects needle-valve VIII (19), described pipeline being sequentially connected with three-way valve II (11), three-way valve III (12), the gas outlet of described three-way valve II (11) is respectively Being connected with described needle-valve I (2), described needle-valve IV (9), described three-way valve III (12), the gas outlet of described three-way valve III (12) is divided Not being connected with described three-way valve II (11), described needle-valve V (10), described needle-valve VI (14), described petroleum tank (21) is by described Needle-valve VIII (19) connects described U-shaped high-temperature high-pressure visual disperser (15).

Device the most according to claim 1, it is characterised in that described leftward space (35) top is provided with standby import and export (26), described rightward space (40) top is provided with standby import and export (27), and described pressure acquisition system (20) is divided by three-way valve Do not connect described standby import and export (26) and described standby import and export (27).

Device the most according to claim 6, it is characterised in that described leftward space (35) top is additionally provided with CO₂Import (25), Described rightward space (40) top is additionally provided with crude oil import (28), and described needle-valve VI (14) is by described CO₂Import (25) connects Described U-shaped high-temperature high-pressure visual disperser (15), described needle-valve VIII (19) connects described U by described crude oil import (28) Type high-temperature high-pressure visual disperser (15).

9. the method for work of device described in claim 6, it is characterised in that concrete steps include:

(1) air-tightness of whole device is checked；

(2) utilize described vacuum pump (1) by described CO₂Gas tank (7), described distillation water pot (8) and described U-shaped high-temperature high-pressure visual Disperser (15) evacuation；

(3) by CO₂, distilled water and crude oil proceed to described CO respectively₂Gas tank (7), described distillation water pot (8) and described petroleum tank (21), in, utilize described primary heater (13) by described CO₂Gas tank (7) and described distillation water pot (8) are heated up to experimental temperature T, utilizes described secondary heater (23) that described petroleum tank (21) is heated up to experimental temperature T, and the span of described T is 25 DEG C-90 DEG C, stand-by；

(4) utilize described temperature control system (44) that described U-shaped high-temperature high-pressure visual disperser (15) is heated to experiment temperature Degree T；

(5) open described needle-valve III (6), described needle-valve V (10) and described needle-valve VI (14), utilize described first constant-flux pump (3) Distilled water in described distillation water pot (8) is pumped in described U-shaped high-temperature high-pressure visual disperser (15), makes distilled water be full of Described U-shaped high-temperature high-pressure visual disperser (15), and it is pressurized to predetermined pressure P1, the span of described P1 is 0.1MPa- 25MPa；

(6) adjusting the pressure in described back pressure gas tank (18) to P2, described P2 is P1-0.1MPa；

(7) close described needle-valve III (6) and described needle-valve V (10), open described needle-valve II (5), described needle-valve IV (9) and institute State needle-valve VII (16), connect back pressure, under constant-pressure conditions, utilize described first constant-flux pump (3) by described CO₂In gas tank (7) CO₂Deliver in the described leftward space (35) of described U-shaped high-temperature high-pressure visual disperser (15), and CO₂Do not arrive described Rightward space (40), closes the first constant-flux pump (3)；

(8) closing described needle-valve II (5), described needle-valve IV (9) and described needle-valve VII (16), described U-shaped high-temperature high-pressure visual expands Put (15) in bulk are closed, and utilize described pressure acquisition system (20) to observe the pressure change that described pressure tap measures, until 30min Interior pressure fall is less than till 1KPa, and the fluid in described U-shaped high-temperature high-pressure visual disperser (15) is in dynamically Poised state, the CO in water₂Reach saturated, form saturated carbon sour water, record the most described high-temperature high-pressure visual disperser (15) pressure in is experiment initial pressure P3；

(9) adjusting the pressure in described back pressure gas tank (18) to P4, described P4 is P3-0.1MPA；

(10) open described needle-valve VII (16), described needle-valve VIII (19) and described needle-valve Ⅸ (22), connect back pressure, in constant voltage Under the conditions of, utilize the second constant-flux pump (24) that the crude oil in described petroleum tank (21) is delivered to the diffusion of described U-shaped high-temperature high-pressure visual In the described rightward space (40) of device (15), and crude oil does not arrive described leftward space (35), closes the second constant-flux pump (24), observe and the crude oil height z that records in described rightward space (40)₀；

(11) described needle-valve VII (16), described needle-valve VIII (19) and described needle-valve Ⅸ (22), described U-shaped High Temperature High Pressure are closed Visual disperser (15) is closed, and utilizes the pressure that pressure tap described in described pressure acquisition system (20) observation t the most in the same time measures Power P (t) changes, record pressure P (t)-time t relation data, till in 30min, pressure fall is less than 1KPa, Record the pressure in the most described U-shaped high-temperature high-pressure visual disperser (15) and be experiment final balance pressure P_eq；

(12) pressure P (t) that step (11) described pressure acquisition system (20) is recorded-time t relation data enters according to the following formula Line nonlinearity matching:

$P\left(t\right)=m_1{e}^{(-\frac{t}{k_1})}+m_2{e}^{(-\frac{t}{k_2})}+{P_{eq}}^{\′}---\left(I\right)$

In formula I, P (t) is the force value recording t, and unit is Pa；P_eq' for nonlinear regression obtain Theoretical Equilibrium pressure Force value, unit is Pa；m₁,m₂,k₁,k₂For based on the parameter that experimental data nonlinear regression is obtained；T is diffusion time, unit For s；

Pressure P (t) in formula I and time t are it is known that draw m by nonlinear fitting₁,m₂,k₁,k₂And P_eq' theoretical value；

(13) according to following formula:

$D_{ab}=\frac{4{z_o}^2}{k_1{\mathrm{\π}}^2}---\left(II\right)$

In formula II, D_abFor CO₂From aqueous phase to the diffusion coefficient of oil phase, unit is m²/s；z_oThe described U recorded for step (10) Type high-temperature high-pressure visual disperser (15) interior crude oil height, unit is m；

Parameter k that step (12) is tried to achieve₁Substitute in formula II, obtain CO₂Migrate diffusion coefficient D to oil phase from aqueous phase_ab。