1. A method for determining the moving speed of an oil-gas interface of a condensate gas cap oil reservoir is characterized by comprising the following steps:

acquiring the pore change volume of a gas cap area and the pore change volume of an oil ring area;

obtaining the current formation pressure of the condensate gas cap reservoir according to the gas cap region pore change volume, the oil ring region pore change volume, the total expansion volume of rocks in the oil-gas reservoir and a condensate gas cap reservoir material balance equation; wherein the condensate gas cap reservoir material balance equation is preset;

and obtaining the oil-gas interface moving speed of the condensate gas cap oil deposit according to the current formation pressure and the gas cap invasion volume.

2. The method of claim 1, wherein the condensate gas cap reservoir material balance equation is:

ΔV_G+ΔV_O+ΔV_Tf＝0

wherein, is Δ V_GRepresents the pore volume change, Δ V, of the gas cap zone_ORepresents the pore volume change, Δ V, of the oil ring region_TfRepresenting a total expanded volume of rock within the reservoir, the total expanded volume of rock within the reservoir being calculated according to the formula:

wherein the content of the first and second substances,is the average rock compressibility, p, of the condensate gas cap reservoir_iThe original formation pressure of the condensate gas cap oil deposit is obtained, m is the ratio of the oil ring pore volume to the gas cap pore volume under the original condition, p is the current formation pressure of the condensate gas cap oil deposit, G is the original natural gas reserve of the formation of the condensate gas cap oil deposit, B_giIs the volume coefficient of the gas head gas under the original condition, y_wiIs the water vapor content in the gas phase under the original conditions, S_wcGIs the irreducible water saturation within the gas cap volume.

3. The method of claim 1 or 2, wherein the obtaining a gas-oil interface movement velocity of the condensate gas cap reservoir from the current formation pressure and gas cap invasion volume comprises:

calculating to obtain the gas cap invasion volume according to the current formation pressure and a first preset formula;

and calculating to obtain the moving speed of the oil-gas interface according to the gas cap invasion volume and a second preset formula.

4. The method of claim 3, wherein the first predetermined formula is:

wherein, V_GinvadeThe gas cap invasion volume, G, the original natural gas reserve of the formation of the condensate gas cap reservoir, G_pFor cumulative natural gas production in the gas cap region, B_gIs the volume coefficient of the current gas cap gas, y_wIs the percentage of water vapor in the condensate gas phase at the current formation pressure, S_coIs the saturation of the condensate in the gas cap volume, S_wcGSaturation of irreducible water in gas cap volume, B_giIs the volume coefficient of the gas-cap gas under the original condition,is the average rock compressibility, p, of the condensate gas cap reservoir_iAnd p is the current formation pressure of the condensate gas cap oil deposit.

5. The method of claim 3, wherein the second predetermined formula is:

wherein v is_ogIs the oil-gas interface moving speed, V_GinvadeIs the gas cap invasion volume, t is the development time, L is the width between the inner and outer boundaries of the oil-gas interface, W is the reservoir width, phi is the formation porosity, S_wcOSaturation of irreducible water in oil ring volume, S_orAlpha is the formation dip, for residual oil saturation.

6. A device for determining the moving speed of an oil-gas interface of a condensate gas cap oil reservoir is characterized by comprising:

the acquiring unit is used for acquiring the pore change volume of the gas cap area and the pore change volume of the oil ring area;

the first obtaining unit is used for obtaining the current formation pressure of the condensate gas cap reservoir according to the gas cap region pore change volume, the oil ring region pore change volume, the total expansion volume of rocks in the oil-gas reservoir and a condensate gas cap reservoir material balance equation; wherein the condensate gas cap reservoir material balance equation is preset;

and the second obtaining unit is used for obtaining the oil-gas interface moving speed of the condensate gas cap oil deposit according to the current formation pressure and the gas cap invasion volume.

7. The apparatus of claim 6, wherein the condensate gas cap reservoir material balance equation is:

ΔV_G+ΔV_O+ΔV_Tf＝0

wherein, is Δ V_GRepresents the pore volume change, Δ V, of the gas cap zone_ORepresents the pore volume change, Δ V, of the oil ring region_TfRepresenting a total expanded volume of rock within the reservoir, the total expanded volume of rock within the reservoir being calculated according to the formula:

wherein the content of the first and second substances,is the average rock compressibility, p, of the condensate gas cap reservoir_iThe original formation pressure of the condensate gas cap oil deposit is obtained, m is the ratio of the oil ring pore volume to the gas cap pore volume under the original condition, p is the current formation pressure of the condensate gas cap oil deposit, G is the original natural gas reserve of the formation of the condensate gas cap oil deposit, B_giIs the volume coefficient of the gas head gas under the original condition, y_wiIs the water vapor content in the gas phase under the original conditions, S_wcGIs the irreducible water saturation within the gas cap volume.

8. The apparatus according to claim 6 or 7, wherein the second obtaining unit comprises:

the first calculation subunit is used for calculating and obtaining the gas cap invasion volume according to the current formation pressure and a first preset formula;

and the second calculation subunit is used for calculating and obtaining the moving speed of the oil-gas interface according to the gas cap invasion volume and a second preset formula.

9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the steps of the method according to any of claims 1 to 5 are implemented when the computer program is executed by the processor.

10. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method of any one of claims 1 to 5.

Background

In nature, most of oil and gas reservoirs with coexisting free gas and crude oil are condensate gas cap reservoirs. Under deep high pressure conditions, most of crude oil in a condensate gas cap oil reservoir has the characteristic of light oil quality. In a condensate gas cap reservoir, oil-gas-water three-phase or oil-gas two-phase movable fluids coexist, and oil-gas-water exist between the oil-gas-water three-phase or oil-gas two-phase movable fluids according to the gravity difference.

When the condensate gas cap oil reservoir is put into development, because oil and gas are in a saturated state, once the formation pressure is reduced, a reverse condensation phenomenon can occur in the condensate gas cap, so that condensate oil loss is caused; the degassing phenomenon of crude oil occurs in an oil ring, the viscosity of the crude oil is increased, and the development difficulty of an oil area is increased. The interaction and the mutual influence between the gas cap and the oil ring are well treated in the condensate gas cap oil reservoir development process, oil and gas channeling is prevented, an oil and gas interface is kept stable or moves slowly, and the condensate gas cap oil reservoir development method is a key factor for realizing reasonable development of the oil and gas reservoirs. Therefore, the development difficulty of the condensate gas cap oil reservoir is much higher than that of a pure gas reservoir or oil reservoir. When the top pressure of the condensate gas is higher than the pressure of the oil ring, the condensate gas in the gas top easily invades into the oil ring downwards, so that the gas channeling of an oil well close to an oil-gas interface is caused, and the oil production capacity of the oil well is reduced; when the pressure of the oil ring is higher than the pressure of the gas cap, the crude oil in the oil ring can intrude upwards into the gas cap, and the intruded crude oil is in a dispersed state and is not easy to be produced to the ground, so that part of crude oil resources are lost. Therefore, how to accurately identify the moving condition of the oil-gas interface of the condensate gas cap reservoir has important significance for the development and adjustment of the oil-gas reservoir.

Disclosure of Invention

Aiming at the problems in the prior art, the embodiment of the invention provides a method and a device for determining the moving speed of an oil-gas interface of a condensate gas cap oil reservoir, which can at least partially solve the problems in the prior art.

On one hand, the invention provides a method for determining the oil-gas interface moving speed of a condensate gas cap oil reservoir, which comprises the following steps:

acquiring the pore change volume of a gas cap area and the pore change volume of an oil ring area;

obtaining the current formation pressure of the condensate gas cap reservoir according to the gas cap region pore change volume, the oil ring region pore change volume, the total expansion volume of rocks in the oil-gas reservoir and a condensate gas cap reservoir material balance equation; wherein the condensate gas cap reservoir material balance equation is preset;

and obtaining the oil-gas interface moving speed of the condensate gas cap oil deposit according to the current formation pressure and the gas cap invasion volume.

In another aspect, the present invention provides a device for determining a moving speed of an oil-gas interface of a condensate gas cap reservoir, including:

the acquiring unit is used for acquiring the pore change volume of the gas cap area and the pore change volume of the oil ring area;

the first obtaining unit is used for obtaining the current formation pressure of the condensate gas cap reservoir according to the gas cap region pore change volume, the oil ring region pore change volume, the total expansion volume of rocks in the oil-gas reservoir and a condensate gas cap reservoir material balance equation; wherein the condensate gas cap reservoir material balance equation is preset;

and the second obtaining unit is used for obtaining the oil-gas interface moving speed of the condensate gas cap oil deposit according to the current formation pressure and the gas cap invasion volume.

In another aspect, the present invention provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the processor executes the program, the processor implements the steps of the method for determining a moving speed of an oil-gas interface of a condensate gas cap reservoir according to any one of the embodiments.

In yet another aspect, the present invention provides a computer readable storage medium, on which a computer program is stored, which when executed by a processor, performs the steps of the method for determining a velocity of a gas-oil interface movement of a condensate gas cap reservoir as described in any of the embodiments above.

The method and the device for determining the oil-gas interface moving speed of the condensate gas cap oil reservoir provided by the embodiment of the invention can obtain the pore change volume of the gas cap area and the pore change volume of the oil ring area, obtain the current formation pressure of the condensate gas cap oil reservoir according to the pore change volume of the gas cap area, the pore change volume of the oil ring area, the total expansion volume of rocks in the oil-gas reservoir and a condensate gas cap oil reservoir substance balance equation, obtain the oil-gas interface moving speed of the condensate gas cap oil reservoir according to the current formation pressure and the gas cap invasion volume, and improve the calculation efficiency of the oil-gas interface moving speed in a condensate gas cap oil reservoir failure exploitation mode.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts. In the drawings:

FIG. 1a is a schematic diagram of a fluid distribution prior to development of a condensate gas cap reservoir provided by an embodiment of the present invention;

FIG. 1b is a schematic illustration of the fluid distribution after development of a condensate gas cap reservoir provided by an embodiment of the present invention;

fig. 2 is a schematic flow chart of a method for determining a moving speed of an oil-gas interface of a condensate gas cap reservoir according to an embodiment of the present invention.

Fig. 3 is a schematic flow chart of a method for determining a moving velocity of a gas-oil interface of a condensate gas cap reservoir according to another embodiment of the present invention.

Fig. 4 is a schematic diagram illustrating the relationship between the oil production rate, the gas production rate, and the moving speed of the oil-gas interface in the depleted production mode according to an embodiment of the present invention.

Fig. 5 is a schematic structural diagram of an apparatus for determining a moving speed of an oil-gas interface of a condensate gas cap reservoir according to an embodiment of the present invention.

Fig. 6 is a schematic structural diagram of a device for determining a moving speed of a gas-oil interface of a condensate gas cap reservoir according to another embodiment of the present invention.

Fig. 7 is a schematic physical structure diagram of an electronic device according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention. It should be noted that the embodiments and features of the embodiments in the present application may be arbitrarily combined with each other without conflict.

In order to facilitate understanding of the technical solutions provided in the present application, the following first describes relevant contents of the technical solutions in the present application. In the embodiment of the invention, the condensate gas cap and the bottom oil ring in the condensate gas cap oil reservoir are assumed to be in the same pressure system, and the oil-gas interface is uniformly pushed; the original formation pressure is higher than the dew point pressure of the condensate gas; bound water exists on both the condensate gas cap and the oil ring; neglecting the dissolution of the condensate gas cap gas in the oil ring and the blow-by of the oil ring escaping dissolved gas into the condensate gas cap; neglecting the adsorption phenomenon of gas in the stratum. The execution subject of the method for determining the oil-gas interface moving speed of the condensate gas cap oil deposit provided by the embodiment of the invention comprises but is not limited to a computer.

Fig. 1a is a schematic diagram of fluid distribution before development of a gas condensate cap oil reservoir according to an embodiment of the present invention, and as shown in fig. 1a, three phases of oil, gas, and water exist before development of the gas condensate cap oil reservoir, which are well-defined. Fig. 1b is a schematic diagram of fluid distribution after development of a condensate gas cap oil reservoir according to an embodiment of the present invention, as shown in fig. 1b, after a certain period of development, when the condensate gas cap pressure is higher than the oil ring pressure, a reverse condensation phenomenon occurs in the condensate gas cap, and condensate oil is formed; when the oil ring pressure is higher than the gas cap pressure, the crude oil degassing phenomenon occurs in the oil ring, and the solution gas escapes.

Fig. 2 is a schematic flow chart of a method for determining a moving speed of an oil-gas interface of a condensate gas cap reservoir according to an embodiment of the present invention, and as shown in fig. 2, the method for determining a moving speed of an oil-gas interface of a condensate gas cap reservoir according to an embodiment of the present invention includes:

s201, acquiring the pore change volume of a gas cap area and the pore change volume of an oil ring area;

specifically, during the development process of the condensate gas cap oil reservoir, with the continuous reduction of the formation pressure, condensate oil in the condensate gas cap can be separated out continuously, and meanwhile, primary water in the gas cap can be evaporated continuously. Therefore, considering the influence of factors such as condensate oil precipitation and formation water evaporation, when the formation pressure is reduced to the current formation pressure, the pore volume change of the gas cap region can be calculated and obtained according to the following formula:

wherein, is Δ V_GFor the pore volume change of the gas cap region, the unit can adopt m³G is the original natural gas reserve of the stratum of the condensate gas cap oil reservoir, and the unit can adopt m³，G_pFor the accumulated natural gas output in the gas cap area, the unit can adopt m³，B_gIs the volume coefficient of the current gas cap gas, B_giIs the volume coefficient of the gas head gas under the original condition, y_wIs the percentage of water vapor in the condensate gas phase at the current formation pressure, S_coIs the saturation of the condensate in the gas cap volume, S_wcGIs the irreducible water saturation in the gas cap volume, y_wiThe water vapor content in the gas phase under the original conditions is expressed in decimal.

In the process of developing the condensate gas cap oil reservoir, along with the continuous reduction of the formation pressure, the dissolved gas in the oil ring can continuously escape and then becomes the free gas of the oil reservoir. Some of the free gas will flow into the wellbore and be produced to the surface, while another part of the free gas will remain in the formation. Therefore, considering the influence of oil ring solution gas escape, the change of the pore volume of the oil ring when the formation pressure is reduced to the current formation pressure is as follows:

wherein, is Δ V_OThe volume of the change of the oil ring area pore space is m³M is the ratio of the oil ring pore volume to the gas cap pore volume under the original condition, G is the original natural gas reserve of the stratum of the condensate gas cap oil reservoir, B_giIs the volume coefficient of the gas head gas under the original condition, S_wcOSaturation of irreducible water in the volume of the oil ring, B_oIs the volume coefficient, y, of the oil ring oil at the current formation pressure_wiIs the water vapor content in the gas phase under the original conditions, S_wcGSaturation of irreducible water in gas cap volume, B_oiIs the volume coefficient of oil ring oil at the original pressure, N_pGround volume, Δ S, for oil ring oil production_wFor the water saturation increase, S, in the oil ring area_gOThe current gas saturation in the oil ring area. The original conditions refer to formation conditions (pressure, temperature, etc.) when the condensate gas cap reservoir is not under development.

Gas saturation S in the current oil ring zone_gOIt can be calculated by the following formula:

wherein S is_wcOSaturation of irreducible water in the volume of the oil ring, R_siIs the dissolved gas-oil ratio, R, of the original condition_sIs the dissolved gas-oil ratio under the current conditions, B_gIs the volume coefficient of the current gas cap gas, B_oiIs the volume coefficient of oil ring oil at the original pressure, N_pGround volume, R, for oil ring oil production_pFor the production gas-oil ratio y under the current conditions_wiIs the water vapor content in the gas phase under the original conditions, S_wcGIs the saturation of the irreducible water in the gas cap volume, m is the ratio of the oil ring pore volume to the gas cap pore volume under the original condition, G is the original natural gas reserve of the stratum of the condensate gas cap oil deposit, B_giIs the volume coefficient of the gas head gas under the original condition.

Considering the influence of natural water invasion of oil reservoir, the oil ring area water saturation increment delta S_wCan be obtained by the following formula:

wherein, W_eIs natural water invasionThe unit can adopt m³，W_pFor the current cumulative water production, B_wIs the volume coefficient of water, y_wiIs the water vapor content in the gas phase under the original conditions, S_wcGIs the saturation of the irreducible water in the gas cap volume, m is the ratio of the oil ring pore volume to the gas cap pore volume under the original condition, G is the original natural gas reserve of the stratum of the condensate gas cap oil deposit, B_giIs the volume coefficient of the gas head gas under the original condition.

S202, obtaining the current formation pressure of the condensate gas cap oil reservoir according to the gas cap area pore change volume, the oil ring area pore change volume, the total expansion volume of rocks in the oil-gas reservoir and a condensate gas cap oil reservoir substance balance equation; wherein the condensate gas cap reservoir material balance equation is preset;

specifically, after obtaining the gas cap region pore variation volume and the oil ring region pore variation volume, the current formation pressure of the condensate gas cap reservoir may be obtained according to the gas cap region pore variation volume, the oil ring region pore variation volume, the total expansion volume of rocks in the oil and gas reservoir, and a condensate gas cap reservoir material balance equation, that is, the gas cap region pore variation volume and the oil ring region pore variation volume are brought into the condensate gas cap reservoir material balance equation, and the total expansion volume of rocks in the oil and gas reservoir is expressed by the current formation pressure of the condensate gas cap reservoir, so as to obtain an equation about the current formation pressure of the condensate gas cap reservoir, and the current formation pressure of the condensate gas cap reservoir may be obtained by solving the equation. Wherein the condensate gas cap reservoir material balance equation is preset.

And S203, obtaining the oil-gas interface moving speed of the condensate gas cap oil deposit according to the current formation pressure and the gas cap invasion volume.

Specifically, after the current formation pressure is obtained, the oil-gas interface movement speed of the condensate gas cap reservoir can be obtained according to the current formation pressure and the gas cap invasion volume.

For example, the gas cap invasion volume is obtained through calculation according to the current formation pressure and a first preset formula, and then the oil-gas interface moving speed is obtained through calculation according to the gas cap invasion volume and a second preset formula. Wherein the first preset formula and the second preset formula are preset.

The method for determining the oil-gas interface moving speed of the condensate gas cap oil reservoir provided by the embodiment of the invention can obtain the pore change volume of the gas cap area and the pore change volume of the oil ring area, obtain the current formation pressure of the condensate gas cap oil reservoir according to the pore change volume of the gas cap area, the pore change volume of the oil ring area, the total expansion volume of rocks in the oil-gas reservoir and a condensate gas cap oil reservoir material balance equation, obtain the oil-gas interface moving speed of the condensate gas cap oil reservoir according to the current formation pressure and the gas cap invasion volume, and improve the calculation efficiency of the oil-gas interface moving speed in a condensate gas cap exhaustion exploitation mode.

On the basis of the above embodiments, further, the condensate gas cap reservoir material balance equation is:

ΔV_G+ΔV_O+ΔV_Tf＝0

wherein, is Δ V_GRepresents the pore volume change, Δ V, of the gas cap zone_ORepresents the pore volume change, Δ V, of the oil ring region_TfAnd (b) representing the expansion volume of the rock in the reservoir, wherein the total expansion volume of the rock in the reservoir is calculated according to the following formula:

wherein the content of the first and second substances,is the average rock compressibility, p, of the condensate gas cap reservoir_iThe original formation pressure of the condensate gas cap oil deposit is obtained, m is the ratio of the oil ring pore volume to the gas cap pore volume under the original condition, p is the current formation pressure of the condensate gas cap oil deposit, G is the original natural gas reserve of the formation of the condensate gas cap oil deposit, B_giIs the volume coefficient of the gas head gas under the original condition, y_wiIs water vapor in gas phase under original conditionContent, S_wcGIs the irreducible water saturation within the gas cap volume.

Specifically, considering the expansion effect of rocks in a gas cap area and an oil ring area respectively, when the original formation pressure of the condensate gas cap oil reservoir is reduced to the current formation pressure, the total expansion volume of the rocks in the oil and gas reservoir is as follows:

wherein, is Δ V_TfFor the total expansion volume of the rock in the reservoir, the unit can be m³，ΔV_GfIs the total expansion volume, Δ V, of the rock in the gas cap_OfIs the total expanded volume of rock in the oil ring,and the average rock compression coefficient of the condensate gas cap oil reservoir.

According to the volume conservation principle in the process of condensate gas cap reservoir development, namely the original oil and gas reservoir pore volume is equal to the sum of the current oil and gas reservoir pore volume and the total expansion volume of rocks in the oil and gas reservoir, the condensate gas cap reservoir material balance equation can be obtained as follows:

ΔV_G+ΔV_O+ΔV_Tf＝0 (6)

and substituting the formula (5) into the formula (6) to obtain an equation about the current formation pressure of the condensate gas cap oil reservoir, and solving to obtain the current formation pressure p of the condensate gas cap oil reservoir by using an iterative calculation method. The specific procedure is to assume the current reservoir pressure drop Δ p, i.e. the current formation pressure p ═ p_iAnd delta p, calculating the expansion volume of the rock in the oil and gas reservoir at the moment through the formula (5), calculating the pore change volume of the gas cap area and the pore change volume of the oil ring area at the moment, substituting the pore change volumes into the condensate gas cap reservoir material balance equation (6), comparing whether the left side and the right side of the equation (6) are equal, and if the left side and the right side are equal, comparing the current formation pressure p with p_i- Δ p, if not equal, re-assuming a formation pressure variation Δ p and repeating the above calculationUntil the current formation pressure p is obtained that meets the computational accuracy requirements. The calculation accuracy requirement is set according to actual needs, and the embodiment of the invention is not limited.

Fig. 3 is a schematic flow chart of a method for determining a moving velocity of an oil-gas interface of a condensate gas cap reservoir according to another embodiment of the present invention, and as shown in fig. 3, based on the foregoing embodiments, further, the obtaining the moving velocity of the oil-gas interface of the condensate gas cap reservoir according to the current formation pressure and the gas cap invasion volume includes:

s2031, calculating to obtain the gas cap invasion volume according to the current formation pressure and a first preset formula;

specifically, after obtaining the current formation pressure, the current formation pressure may be substituted into a first preset formula to calculate the gas cap invasion volume.

S2032, calculating and obtaining the moving speed of the oil-gas interface according to the gas cap invasion volume and a second preset formula.

Specifically, after the gas cap invasion volume is obtained through calculation, the gas cap invasion volume is substituted into a second preset formula, and the oil-gas interface moving speed is obtained through calculation.

On the basis of the foregoing embodiments, further, the first preset formula is:

wherein, V_GinvadeThe gas cap invasion volume, G, the original natural gas reserve of the formation of the condensate gas cap reservoir, G_pFor cumulative natural gas production in the gas cap region, B_gIs the volume coefficient of the current gas cap gas, y_wIs the percentage of water vapor in the condensate gas phase at the current formation pressure, S_coIs the saturation of the condensate in the gas cap volume, S_wcGSaturation of irreducible water in gas cap volume, B_giIs the volume coefficient of the gas-cap gas under the original condition,is the average rock compressibility, p, of the condensate gas cap reservoir_iAnd p is the current formation pressure of the condensate gas cap oil deposit.

Specifically, under the condition of cooperative development of the condensate gas cap and the oil ring, assuming that the oil-gas interface moves towards the direction of the oil ring, the gas cap intrusion volume V can be obtained_GinvadeThe calculation formula of (2) is as follows:

wherein, V_GPore volume, Δ V, at the current conditions in the gas cap zone_GfIs the total expansion volume of the rock in the gas cap, V_GiPore volume at the original condition of the gas cap zone.

On the basis of the foregoing embodiments, further, the second preset formula is:

wherein v is_ogIs the oil-gas interface moving speed, V_GinvadeIs the gas cap invasion volume, t is the development time, L is the width between the inner and outer boundaries of the oil-gas interface, W is the reservoir width, phi is the formation porosity, S_wcOSaturation of irreducible water in oil ring volume, S_orAlpha is the formation dip, for residual oil saturation.

Specifically, according to the invasion volume of the gas cap, the moving speed of the oil-gas interface can be calculated by using a volumetric method, and if the moving speeds of the inner oil-gas interface and the outer oil-gas interface are equal, namely the oil-gas interface moves downwards in parallel, the invasion volume V of the gas cap is calculated_GinvadeCan be expressed as:

V_Ginvade＝LhWφ(1-S_wcO-S_or)＝LWφ(1-S_wcO-S_or)xsinα (8)

wherein L is between the inner and outer boundaries of the oil-gas interfaceThe unit of the width can adopt m, h is the distance of longitudinal movement of the oil-gas interface, m and W are the width of the oil deposit, x is the distance of transverse movement of the oil-gas interface, m and phi are the porosity of the stratum, and S is_wcOSaturation of irreducible water in oil ring volume, S_orFor residual oil saturation, α is the formation dip, and the units may be degrees.

Oil-gas interface transverse moving speed v_ogCan be expressed as:

v_og＝x/t (9)

wherein v is_ogThe unit of the transverse moving speed of the oil-gas interface can be meter/year, x is the transverse moving distance of the oil-gas interface, the unit can be m, t is development time, and the unit can be year. The oil-gas interface transverse moving speed here is the oil-gas interface moving speed described in the above embodiments.

From equation (8) and equation (9), the second preset equation can be obtained as:

the condensate gas cap and oil ring collaborative exploitation is carried out by utilizing a failure exploitation mode, and the moving direction of an oil-gas interface is determined by the volume depletion difference of the gas cap and the oil ring. When the gas cap void volume is larger than the oil ring, the oil-gas interface moves towards the gas cap direction; when the oil ring void volume is larger than the gas cap, the oil-gas interface moves towards the oil ring. Therefore, when depleted oil and gas are cooperatively exploited, the main development factors influencing the stability of the oil-gas interface are the gas-cap oil production speed and the oil ring oil production speed.

Taking a north Gamma-shaped gas cap oil reservoir of a Nafel oil-gas field as a research object, respectively calculating oil and gas interface moving speeds under different oil ring oil extraction speeds and different gas cap gas production speeds, and establishing a relation among the oil extraction speed, the gas production speed and the oil and gas interface moving speed, as shown in fig. 4, wherein the gas production speed is set to be 0%, 1%, 2%, 4% and 6%, and the oil extraction speed is set to be 0%, 0.3%, 0.6%, 0.9% and 1.2%. In fig. 4, the oil ring region is represented by a horizontal axis or more, and the gas cap region is represented by a horizontal axis or less. It can also be seen from fig. 4 that the moving directions of the oil-gas interface are different for different oil recovery speeds and gas recovery speed combinations, thereby proving the inference of the main control factors affecting the stability of the oil-gas interface when the depleted oil-gas is simultaneously recovered.

From the relationship between the oil production rate, the gas production rate and the oil-gas interface moving speed in the depleted production mode shown in fig. 4, it can be seen that:

(1) when the gas cap is larger than the oil ring, the oil-gas interface moves towards the direction of the gas zone. When the gas production speed is the same, the oil production speed is higher, the oil ring void speed is increased, so that the pressure difference between gas cap oil rings is reduced, and the oil-gas interface moving speed is lower; when the oil extraction speed is the same, the gas extraction speed is higher, so that the gas cap pressure is reduced faster, the pressure difference between gas cap oil rings is larger and larger, and the moving speed of an oil-gas interface is larger and larger.

(2) When the oil ring depletion is larger than the gas cap depletion, the oil-gas interface moves towards the direction of the oil area. Under the same gas production speed, the higher the oil production speed is, the faster the oil ring pressure is reduced, the greater the pressure difference between the gas cap oil rings is, and the greater the moving speed of an oil-gas interface to an oil area is; under the same oil extraction speed, the larger the gas extraction speed is, the faster the gas cap pressure is reduced, the pressure difference between gas cap oil rings is gradually reduced, and the moving speed of an oil-gas interface is also reduced.

(3) For the oil extraction speed of a certain oil ring, a reasonable gas extraction speed exists, and the relative stability of an oil-gas interface is realized (namely the moving speed of the oil-gas interface is zero); when the oil-gas interface is stable, the reasonable gas production speed and oil production speed are in direct proportion relation. Therefore, when the depletion type gas cap oil ring is cooperatively exploited, the oil-gas invasion or gas-gas invasion phenomenon can be effectively prevented as long as the size relation between the oil production speed and the gas production speed is reasonably matched and the oil-gas interface is kept relatively stable.

Fig. 5 is a schematic structural diagram of a device for determining a moving speed of an oil-gas interface of a condensate gas cap reservoir according to an embodiment of the present invention, and as shown in fig. 5, the device for determining a moving speed of an oil-gas interface of a condensate gas cap reservoir according to an embodiment of the present invention includes an obtaining unit 501, a first obtaining unit 502, and a second obtaining unit 503, where:

the acquiring unit 501 is used for acquiring the pore change volume of the gas cap area and the pore change volume of the oil ring area; the first obtaining unit 502 is configured to obtain a current formation pressure of the condensate gas cap reservoir according to the gas cap region pore variation volume, the oil ring region pore variation volume, a total expansion volume of rocks in the oil and gas reservoir, and a condensate gas cap reservoir material balance equation; wherein the condensate gas cap reservoir material balance equation is preset; the second obtaining unit 503 is configured to obtain an oil-gas interface moving speed of the condensate gas cap reservoir according to the current formation pressure and the gas cap invasion volume.

Specifically, during the development process of the condensate gas cap oil reservoir, with the continuous reduction of the formation pressure, condensate oil in the condensate gas cap can be separated out continuously, and meanwhile, primary water in the gas cap can be evaporated continuously. Therefore, considering the influence of factors such as condensate oil precipitation and formation water evaporation, when the formation pressure is reduced to the current formation pressure, the obtaining unit 501 may calculate and obtain the pore volume change of the gas cap region according to the formula (1).

In the process of developing the condensate gas cap oil reservoir, along with the continuous reduction of the formation pressure, the dissolved gas in the oil ring can continuously escape and then becomes the free gas of the oil reservoir. Some of the free gas will flow into the wellbore and be produced to the surface, while another part of the free gas will remain in the formation. Therefore, when the formation pressure is reduced to the current formation pressure in consideration of the influence of the oil ring solution gas escape, the obtaining unit 501 may calculate and obtain the oil ring pore volume change according to the formula (2).

After obtaining the gas cap region pore change volume and the oil ring region pore change volume, the first obtaining unit 502 may obtain the current formation pressure of the gas cap reservoir according to the gas cap region pore change volume, the oil ring region pore change volume, the total expansion volume of the rocks in the oil and gas reservoir, and a condensate gas cap reservoir material balance equation, that is, the gas cap region pore change volume and the oil ring region pore change volume are brought into the condensate gas cap reservoir material balance equation, and the total expansion volume of the rocks in the oil and gas reservoir is expressed by the current formation pressure of the condensate gas cap reservoir, so as to obtain an equation about the current formation pressure of the condensate gas cap reservoir, and the current formation pressure of the condensate gas cap reservoir can be obtained by solving the equation. Wherein the condensate gas cap reservoir material balance equation is preset.

After obtaining the current formation pressure, the second obtaining unit 503 may obtain the oil-gas interface moving speed of the condensate gas cap reservoir according to the current formation pressure and the gas cap invasion volume.

The device for determining the oil-gas interface moving speed of the condensate gas cap oil reservoir provided by the embodiment of the invention can obtain the pore change volume of the gas cap area and the pore change volume of the oil ring area, obtain the current formation pressure of the condensate gas cap oil reservoir according to the pore change volume of the gas cap area, the pore change volume of the oil ring area, the total expansion volume of rocks in the oil-gas reservoir and a condensate gas cap oil reservoir material balance equation, obtain the oil-gas interface moving speed of the condensate gas cap oil reservoir according to the current formation pressure and the gas cap invasion volume, and improve the calculation efficiency of the oil-gas interface moving speed in a condensate gas cap exhaustion exploitation mode.

On the basis of the above embodiments, further, the condensate gas cap reservoir material balance equation is:

ΔV_G+ΔV_O+ΔV_Tf＝0

wherein, is Δ V_GRepresents the pore volume change, Δ V, of the gas cap zone_ORepresents the pore volume change, Δ V, of the oil ring region_TfRepresenting a total expanded volume of rock within the reservoir, the total expanded volume of rock within the reservoir being calculated according to the formula:

wherein the content of the first and second substances,is the average rock compressibility, p, of the condensate gas cap reservoir_iFor said condensate gas cap reservoirOriginal formation pressure, m is the ratio of the oil ring pore volume to the gas cap pore volume under the original condition, p is the current formation pressure of the condensate gas cap oil deposit, G is the original natural gas reserve of the formation of the condensate gas cap oil deposit, B_giIs the volume coefficient of the gas head gas under the original condition, y_wiIs the water vapor content in the gas phase under the original conditions, S_wcGIs the irreducible water saturation within the gas cap volume.

Fig. 6 is a schematic structural diagram of a device for determining a moving speed of an oil-gas interface of a condensate gas cap reservoir according to another embodiment of the present invention, as shown in fig. 6, on the basis of the foregoing embodiments, further, the second obtaining unit 503 includes a first calculating subunit 5031 and a second calculating subunit 5032, where:

the first calculating subunit 5031 is configured to calculate and obtain the gas cap invasion volume according to the current formation pressure and a first preset formula; the second calculating subunit 5032 is configured to calculate and obtain the moving speed of the oil-gas interface according to the gas cap intrusion volume and a second preset formula.

Specifically, after obtaining the current formation pressure, the first calculation subunit 5031 may substitute the current formation pressure into a first preset formula to calculate the gas cap invasion volume.

After the gas cap invasion volume is obtained through calculation, the second calculation subunit 5032 substitutes the gas cap invasion volume into a second preset formula to obtain the oil-gas interface movement speed through calculation.

The embodiment of the apparatus provided in the embodiment of the present invention may be specifically configured to execute the processing flows of the above method embodiments, and the functions of the apparatus are not described herein again, and refer to the detailed description of the above method embodiments.

Fig. 7 is a schematic physical structure diagram of an electronic device according to an embodiment of the present invention, and as shown in fig. 7, the electronic device may include: a processor (processor)701, a communication Interface (Communications Interface)702, a memory (memory)703 and a communication bus 704, wherein the processor 701, the communication Interface 702 and the memory 703 complete communication with each other through the communication bus 704. The processor 701 may call logic instructions in the memory 703 to perform the following method: acquiring the pore change volume of a gas cap area and the pore change volume of an oil ring area; obtaining the current formation pressure of the condensate gas cap reservoir according to the gas cap region pore change volume, the oil ring region pore change volume, the total expansion volume of rocks in the oil-gas reservoir and a condensate gas cap reservoir material balance equation; wherein the condensate gas cap reservoir material balance equation is preset; and obtaining the oil-gas interface moving speed of the condensate gas cap oil deposit according to the current formation pressure and the gas cap invasion volume.

In addition, the logic instructions in the memory 703 can be implemented in the form of software functional units and stored in a computer readable storage medium when the software functional units are sold or used as independent products. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

The present embodiment discloses a computer program product comprising a computer program stored on a non-transitory computer readable storage medium, the computer program comprising program instructions which, when executed by a computer, enable the computer to perform the method provided by the above-mentioned method embodiments, for example, comprising: acquiring the pore change volume of a gas cap area and the pore change volume of an oil ring area; obtaining the current formation pressure of the condensate gas cap reservoir according to the gas cap region pore change volume, the oil ring region pore change volume, the total expansion volume of rocks in the oil-gas reservoir and a condensate gas cap reservoir material balance equation; wherein the condensate gas cap reservoir material balance equation is preset; and obtaining the oil-gas interface moving speed of the condensate gas cap oil deposit according to the current formation pressure and the gas cap invasion volume.

The present embodiment provides a computer-readable storage medium, which stores a computer program, where the computer program causes the computer to execute the method provided by the above method embodiments, for example, the method includes: acquiring the pore change volume of a gas cap area and the pore change volume of an oil ring area; obtaining the current formation pressure of the condensate gas cap reservoir according to the gas cap region pore change volume, the oil ring region pore change volume, the total expansion volume of rocks in the oil-gas reservoir and a condensate gas cap reservoir material balance equation; wherein the condensate gas cap reservoir material balance equation is preset; and obtaining the oil-gas interface moving speed of the condensate gas cap oil deposit according to the current formation pressure and the gas cap invasion volume.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

In the description herein, reference to the description of the terms "one embodiment," "a particular embodiment," "some embodiments," "for example," "an example," "a particular example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.