Method and system for determining flow equilibrium point radius during gas condensate precipitation

Abstract

The embodiment of the invention provides a method and system for determining the radius of a flow equilibrium point during gas condensate precipitation, and belongs to the field of oil and gas reservoir development. The method comprises the steps of determining equivalent production time of a gas well based on production parameters of the gas well; based on the stable gas production rate of the gas well, the equivalent production time of the gas well and physical parameters in the retrograde condensation process, the static saturation degree of the condensate oil and the dynamic saturation degree of the condensate oil are determined, and the static saturation degree of the condensate oil and the dynamic saturation degree of the condensate oil are related to the equivalent production time; and based on the dynamic saturation of the condensate oil and the equivalent production time, determining the radius of a flow equilibrium point when the condensate oil of the condensate gas reservoir is separated out. According to the embodiment of the invention, the change of the radius can be quantitatively analyzed, and an important theoretical basis is provided for understanding the seepage law of the condensate gas reservoir and targeted regulation and control countermeasures.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas reservoir development, in particular to a method and system for determining the flow balance point radius when condensate is precipitated, a computer readable storage medium and a computer program product. BACKGROUND

[0002] There are differences in accumulation characteristics and percolation laws between gas reservoirs and oil reservoirs, and there are deficiencies in evaluation methods and data information, and there are differences in development methods and adjustment strategies. The core problem is the percolation law in the underground and the strategy for improving the recovery rate. In terms of evaluation methods, gas reservoir dynamic analysis needs to carry out well-reservoir integrated multi-node system analysis to clarify the synergistic mechanism and process of gas-water-oil-solid multi-medium, but at present, the evaluation methods of gas reservoirs mainly use single gas reservoir engineering or numerical simulation method, which focuses on critical gas production calculation, oil casing pressure difference analysis wellbore liquid loading, well test analysis of near-well percolation change, formation pressure and dynamic reserve relationship, flow resistance distribution between nodes, formation condensate production, produced water salinity analysis to determine the produced water source, and produced gas component analysis. Especially in the aspect of condensate distribution, there is a lack of systematic and overall analysis concept and method.

[0003] On the basis of current theoretical understanding, reservoir description and geological modeling, it is urgent to use oil and gas reservoir engineering methods as the main means to analyze the production rules and dynamic characteristics of oil, gas and water, to clarify the condensate gas reservoir condensate precipitation, water invasion, liquid loading and production rules, to determine the main development contradictions, especially the condensate generation, deposition and influence process and rule understanding, and to further understand the development characteristics and main control factors of condensate gas reservoirs.

[0004] The radius of the flow balance point when the condensate is precipitated in the condensate gas reservoir at different development stages changes, and the present field lacks the research on the change rule of the radius, so that the percolation law of the condensate gas reservoir cannot be understood and targeted control measures cannot be taken. SUMMARY

[0005] The purpose of the embodiments of the present application is to provide a method and system for determining the flow balance point radius when condensate is precipitated, a computer readable storage medium and a computer program product, which can partially or completely solve the above technical problems.

[0006] To achieve the above object, the embodiment of the present application provides a method for determining a flow balance point radius when condensate is separated, which comprises: determining an equivalent production time of a gas well based on production parameters of the gas well, wherein the production parameters of the gas well comprise a well control radius, an equivalent gas production corresponding to the well bore radius and a stable gas production, and the equivalent production time of the gas well is related to the well control radius; determining a static saturation of the condensate and a dynamic saturation of the condensate based on the stable gas production of the gas well, the equivalent production time of the gas well and physical parameters in a retrograde condensation process, wherein the static saturation of the condensate and the dynamic saturation of the condensate are related to the equivalent production time; and determining the flow balance point radius when the condensate gas reservoir separates the condensate based on the dynamic saturation of the condensate and the equivalent production time.

[0007] Optionally, the determining the equivalent production time of the gas well based on the production parameters of the gas well comprises: determining the equivalent production time t of the gas well according to the well control radius, the equivalent gas production corresponding to the well bore radius and the stable gas production and the following formula: wherein Q p represents an elastic gas production of the gas well within the well control range; P i represents an original formation pressure; represents an average formation pressure within the well control range; r represents the well control radius of the gas well; Q e represents a displacement gas supply of the gas well outside the well control range; r e represents a distance from the well point to the condensate gas reservoir boundary; Q r (r) represents the equivalent gas production of the gas well; q g represents the stable gas production of the gas well.

[0008] Optionally, the physical parameters comprise a formation pressure drop, an increase amount of the condensate saturation within a unit pore volume in the retrograde condensation process and a reduction amount of the condensate concentration in the unit gas in a gas phase during the retrograde condensation process,

[0009] The determining the static saturation of the condensate based on the stable gas production of the gas well, the equivalent production time of the gas well and the physical parameters in the retrograde condensation process comprises: determining a static saturation formation rate of the condensate based on the stable gas production of the gas well, the equivalent production time of the gas well, the formation pressure drop in the retrograde condensation process, the increase amount of the condensate saturation within the unit pore volume in the retrograde condensation process and the reduction amount of the condensate concentration in the unit gas in the gas phase; and determining the static saturation of the condensate based on the static saturation formation rate of the condensate, the stable gas production of the gas well and a volume coefficient of the condensate gas.

[0010] Optionally, determining the dynamic saturation of the condensate oil based on the stable gas production of the gas well, the equivalent production time of the gas well, and the physical parameters during the reverse condensation process includes: determining the increased and decreased condensate oil volume and the net outflow volume of condensate oil under the condensation effect based on the stable gas production of the gas well, the equivalent production time of the gas well, the formation pressure drop and the decrease in condensate oil concentration during the reverse condensation process; determining the dynamic saturation formation rate of the condensate oil during the reverse condensation process based on the increased and decreased condensate oil volume and the net outflow volume of condensate oil under the condensation effect; and determining the dynamic saturation of the condensate oil based on the dynamic saturation formation rate of the condensate oil during the reverse condensation process.

[0011] Optionally, the dynamic saturation formation rate of the condensate oil during the anti-condensation process is determined based on the increase and decrease in condensate oil volume under the condensation action and the net outflow volume of the condensate oil, including by using the following formula:

[0012] V o1 =2πrhφdrdS o ',

[0013] V o2 =q g dtdC-V o3 ,

[0014]

[0015] V o1 =V o2 ,

[0016] Determine the dynamic saturation formation rate of the condensate oil during the anti-condensation process. Among them, V o1 V represents the increase in condensate oil volume during the anti-condensation process; o2 V represents the reduction in condensate oil volume during the anti-condensation process; o3 The net outflow volume of condensate oil during the reverse condensation process is represented by r; the well control radius of the gas well is represented by h; the effective thickness of the condensate gas reservoir is represented by Φ; and the porosity of the condensate gas reservoir is represented by S. o ' represents the dynamic saturation of condensate oil; C represents the concentration of condensate oil present in the gas phase; μ g P represents the viscosity of the gas phase. sc Z represents the standard surface pressure; T represents the gas deviation coefficient; y represents the temperature of the condensate reservoir; μ represents the anti-condensation factor; o K represents the viscosity of the condensate oil; K represents the effective permeability of the condensate gas reservoir; K rg P represents the relative permeability of the gas. r T represents the formation pressure at the well control radius;sc Indicates the standard ground temperature; K ro This indicates the relative permeability of the oil phase.

[0017] Optionally, determining the dynamic saturation of the condensate oil based on the dynamic saturation formation rate of the condensate oil during the anti-condensation process includes: determining the dynamic saturation S of the condensate oil based on the dynamic saturation formation rate of the condensate oil during the anti-condensation process and the following formula. o ':

[0018]

[0019] B g This represents the volume coefficient of the condensate gas.

[0020] Optionally, determining the flow equilibrium point radius at the time of condensate oil precipitation in the condensate gas reservoir based on the dynamic saturation of the condensate oil and the equivalent production time includes: determining the flow equilibrium point radius r(t) at the time of condensate oil precipitation in the condensate gas reservoir based on the dynamic saturation of the condensate oil, the equivalent production time, and the following formula:

[0021] K ro ′ represents the relative permeability of the oil phase.

[0022] Optionally, the method further includes: determining the formation time of the critical dynamic saturation of condensate oil in the anti-condensation process based on the static saturation of condensate oil and the critical saturation of condensate oil in the anti-condensation process.

[0023] On the other hand, the present invention also provides a system for determining the flow equilibrium point radius when condensate oil separates out. The system includes: a first determining module for determining the equivalent production time of a gas well based on the production parameters of the gas well, wherein the production parameters of the gas well include a well control radius, an equivalent gas production rate corresponding to the wellbore radius, and a stable gas production rate, and the equivalent production time of the gas well is related to the well control radius; a second determining module for determining the static saturation and dynamic saturation of the condensate oil based on the stable gas production rate of the gas well, the equivalent production time of the gas well, and physical parameters in the reverse condensation process, wherein the static saturation and dynamic saturation of the condensate oil are related to the equivalent production time; and a third determining module for determining the flow equilibrium point radius when condensate oil separates out of the condensate gas reservoir based on the dynamic saturation of the condensate oil and the equivalent production time.

[0024] Optionally, the first determining module is used to determine the equivalent production time of the gas well based on the gas well's production parameters, including: determining the equivalent production time t of the gas well according to the well control radius, the equivalent gas production and stable gas production corresponding to the wellbore radius, and the following formula: Among them, Q p P represents the elastic gas production of a gas well within the well control area. i Indicates the original formation pressure; The value of Q represents the average formation pressure within the well control area; r represents the well control radius of the gas well; e This indicates the displacement gas supply from gas wells outside the well control area; r e Q represents the distance from the well point to the boundary of the condensate gas reservoir; r (r) represents the equivalent gas production of the gas well; q g This indicates the stable gas production of a gas well.

[0025] In another aspect, the present invention also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the method for determining the radius of the flow equilibrium point when condensate oil is separated.

[0026] In another aspect, the present invention also provides a computer program product, which, when executed by a processor, implements the method for determining the radius of the flow equilibrium point when condensate oil is separated.

[0027] Based on the above technical solution, the equivalent production time of the gas well is determined according to the production parameters of the gas well; the static saturation and dynamic saturation of the condensate are determined according to the stable gas production of the gas well, the equivalent production time of the gas well, the formation pressure drop during the reverse condensation process, the increase in condensate oil saturation per unit pore volume and the decrease in the concentration of condensate oil in the gas phase per unit gas during the reverse condensation process; and the flow equilibrium point radius when condensate oil is separated from the condensate gas reservoir is determined according to the dynamic saturation of the condensate oil and the equivalent production time. This invention determines the static and dynamic saturation of condensate oil by determining the equivalent production time of the gas well and the physical parameters during the reverse condensation process. Based on the dynamic saturation of condensate oil and the equivalent production time of the gas well, a formula is derived to determine the radius of the flow equilibrium point when condensate oil is released from the condensate gas reservoir at different development stages. This formula changes with the production time, allowing for quantitative analysis of the change in this radius. This provides an important theoretical basis for understanding the seepage law of condensate gas reservoirs and developing targeted control strategies.

[0028] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0029] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0030] Figure 1 This is a flowchart of a method for determining the radius of the flow equilibrium point during condensate oil precipitation, provided in an embodiment of the present invention.

[0031] Figure 2 This is a flowchart for determining the static saturation of the condensate oil provided in an embodiment of the present invention;

[0032] Figure 3 This is a flowchart for determining the dynamic saturation of the condensate oil according to an embodiment of the present invention;

[0033] Figure 4 This is a production dynamic curve diagram of typical well No. 1 provided in an embodiment of the present invention;

[0034] Figure 5 This is a graph showing the change of the flow equilibrium point radius over time for a typical well No. 1 provided in this embodiment of the invention.

[0035] Figure 6 This is a production dynamic curve diagram of a typical well No. 2 provided in this embodiment of the invention;

[0036] Figure 7 This is a graph showing the change of the flow equilibrium point radius over time for a typical well No. 2 provided in this embodiment of the invention.

[0037] Figure 8 This is a production dynamic curve diagram of a typical well No. 3 provided in this embodiment of the invention;

[0038] Figure 9 This is a graph showing the change of the flow equilibrium point radius over time for a typical well No. 3 provided in this embodiment of the invention;

[0039] Figure 10 This is a structural diagram of the system for determining the radius of the flow equilibrium point provided in an embodiment of the present invention. Detailed Implementation

[0040] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0041] Figure 1 This is a flowchart of a method for determining the radius of the flow equilibrium point during condensate oil precipitation, provided by an embodiment of the present invention. The method includes the following steps S11-S13.

[0042] S11. Based on the production parameters of the gas well, determine the equivalent production time of the gas well.

[0043] The production parameters of the gas well include the well control radius, the equivalent gas production rate corresponding to the wellbore radius, and the stable gas production rate. The equivalent production time of the gas well is related to the well control radius.

[0044] Further, determining the equivalent production time of the gas well based on its production parameters includes: determining the equivalent production time t of the gas well based on the well control radius, the equivalent gas production rate and stable gas production rate corresponding to the wellbore radius, and the following formula:

[0045]

[0046] Among them, Q p P represents the elastic gas production of a gas well within the well control area. i Indicates the original formation pressure; The value of Q represents the average formation pressure within the well control area; r represents the well control radius of the gas well; e This indicates the displacement gas supply from gas wells outside the well control area; r e Q represents the distance from the well point to the boundary of the condensate gas reservoir; r (r) represents the equivalent gas production of the gas well; q g This indicates the stable gas production of a gas well.

[0047] Specifically, based on the law of conservation of mass, the elastic gas production Q within the well control area is calculated. p :

[0048]

[0049] Based on the actual cumulative gas production, the displacement gas supply Q outside the well control range is obtained. e :

[0050]

[0051] The equivalent gas production Q of the gas well is obtained. r :

[0052]

[0053] The equivalent production time of the gas well is obtained:

[0054]

[0055] Among them, Q p The elastic gas production of the gas well within the well control area, expressed in cm³. 3 Q represents the elastic recoverable reserves of the gas well, in cm³. 3 ;P iThis represents the original formation pressure, expressed in atm. is the average formation pressure within the well control area, in atm; r is the well control radius of the gas well, in cm; Q e The displacement gas supply from gas wells outside the well control area, expressed in cm³. 3 Q T This represents the actual cumulative gas production of the gas well, expressed in cm³. 3 ;r e Q represents the distance from the well point to the boundary of the condensate gas reservoir, in cm. r (r) represents the equivalent gas production of the gas well, in cm³. 3 t represents the equivalent production time of the gas well, in seconds; q g The stable gas production of a gas well, expressed in cm³. 3 / s. Among these parameters, Q p Q, P i , Q T r e and q g It can be obtained through existing technologies such as well logging and is considered as known data, while the well radius r changes with the equivalent production time.

[0056] S12. Based on the stable gas production of the gas well, the equivalent production time of the gas well, and the physical parameters in the anti-condensation process, determine the static saturation of the condensate oil and the dynamic saturation of the condensate oil.

[0057] The static saturation and dynamic saturation of the condensate oil are related to the equivalent production time.

[0058] The physical parameters include formation pressure drop, the increase in condensate oil saturation per unit pore volume during reverse condensation, and the decrease in the concentration of condensate oil in the gas phase per unit gas.

[0059] Figure 2 This is a flowchart illustrating how to determine the static saturation of condensate oil according to an embodiment of the present invention. Determining the static saturation of the condensate oil based on the stable gas production of the gas well, the equivalent production time of the gas well, and the physical parameters during the reverse condensation process includes the following steps S121-S122.

[0060] S121. Based on the stable gas production of the gas well, the equivalent production time of the gas well, the formation pressure drop during the reverse condensation process, the increase in condensate oil saturation per unit pore volume during the reverse condensation process, and the decrease in the concentration of condensate oil in the gas phase per unit gas, determine the static saturation formation rate of the condensate oil.

[0061] Specifically, assuming that the gas well produces a stable output qg Production takes a certain time, e.g., dt (i.e., the equivalent production time t is differentiated). Due to the anti-condensation effect caused by the formation pressure drop dP, the saturation of condensate oil within the unit pore volume increases by dS. o On the other hand, this leads to a decrease in the concentration of condensate oil in the gaseous phase per unit gas by dC. The increase in condensate oil volume due to the former should be equal to the decrease in condensate oil volume due to the latter. Therefore, the expression for the formation rate of static saturation of condensate oil is derived as follows:

[0062]

[0063] Among them, S o q represents the saturation of condensate oil, expressed in f; t represents the equivalent production time of the gas well, expressed in seconds; q represents the saturation of the condensate oil. g The stable gas production of a gas well, expressed in cm³. 3 / s; P is the formation pressure in atm; C is the concentration of condensate oil in the gas phase; r is the well control radius of the gas well in cm; h is the effective thickness of the condensate gas reservoir in cm; Φ is the porosity of the condensate gas reservoir in f. Only r on the right side of the formula is unknown; the other parameters can be obtained using existing technologies.

[0064] S122. Determine the static saturation of the condensate oil based on the static saturation formation rate of the condensate oil, the stable gas production of the gas well, and the volume coefficient of the condensate gas.

[0065] Specifically, the formula for calculating the stable production rate of a known gas well is as follows:

[0066]

[0067] And the known volume factor B of the condensate gas. g :

[0068]

[0069] If we define the reduction in condensate oil per unit gas pressure drop as the anti-condensation factor y: y = dC / dP, then from equations (5) to (7), we can obtain the expression for the static saturation of condensate oil as follows:

[0070]

[0071] In the formula: K is the effective permeability of the condensate gas reservoir, in μm. 2 ;K rg The gas relative permeability is expressed in f (μ). g B is the gas phase viscosity, mPa·s; g P is the volume factor of the condensate gas, in units of f; scρ is the surface standard pressure, in atm; Z is the gas deviation coefficient, in f; T is the temperature of the condensate gas reservoir, in K; P r T represents the formation pressure at the well control radius, in atm. sc Ground standard temperature, in Kelvin (K); S o y represents the static saturation of condensate oil, in units of f; y represents the anti-condensation factor, in units of cm. 3 / (atm·cm 3 The formula only contains r, t, and S. o The variable is unknown; all others are known values. Based on the above formula, the expression for the static saturation permeability of condensate oil can be determined.

[0072] Furthermore, the method further includes: determining the critical dynamic saturation formation time of the condensate oil in the anti-condensation process based on the static saturation of the condensate oil and the critical saturation of the condensate oil in the anti-condensation process.

[0073] Specifically, the critical dynamic saturation of condensate oil, corresponding to its transition from static to dynamic states, is a crucial parameter reflecting its flowability within the formation. Condensate oil only begins to flow after reaching the critical flow saturation. The formation time directly impacts the accumulation and flow state of condensate oil in the formation; a faster formation time means the condensate oil can begin to flow earlier, thus improving condensate oil recovery. The critical time significantly affects condensate oil recovery, gas well productivity, and stable production period. Therefore, determining the travel time to the critical dynamic saturation is of great importance.

[0074] When S o =S oc Then, from equation (8), the expression for the formation time t0 of the critical dynamic saturation of condensate oil during the anti-condensation process can be obtained as follows:

[0075]

[0076] In the formula: t0 is the time for the critical dynamic saturation of condensate oil to form during the reverse condensation process, in seconds; r is the well control radius of the gas well, in centimeters; h is the effective thickness of the condensate gas reservoir, in centimeters; Φ is the porosity of the condensate gas reservoir, in f; and K is the effective permeability of the condensate gas reservoir, in μm. 2 ;K rg P represents the relative permeability of the gas, expressed in f. r T represents the formation pressure at the well control radius, in atm. sc Ground standard temperature, in Kelvin (K); S oc q represents the critical saturation of condensate oil during the anti-condensation process, expressed in f. g The stable gas production of a gas well, expressed in cm³. 3 / s;μ g P is the gas phase viscosity, in mPa·s. sc ρ is the surface standard pressure, in atm; Z is the gas deviation coefficient, in f; T is the temperature of the condensate reservoir, in K; y is the anti-condensation factor, in cm. 3 / (atm·cm 3 ).

[0077] The embodiments of the present invention determine the critical dynamic saturation formation time t0 of condensate oil through the above scheme, which is beneficial to take corresponding measures to optimize the extraction process and thereby improve the recovery rate of oil and gas resources.

[0078] Figure 3 This is a flowchart illustrating how to determine the dynamic saturation of condensate oil according to an embodiment of the present invention. Determining the dynamic saturation of the condensate oil based on the stable gas production of the gas well and the physical parameters during the reverse condensation process includes the following steps S125-S127.

[0079] S125. Based on the stable gas production of the gas well, the equivalent production time of the gas well, the formation pressure drop and the reduction in condensate concentration during the reverse condensation process, determine the increased condensate volume, the decreased condensate volume, and the net outflow volume of condensate under the condensation action.

[0080] Specifically, the stable production rate of gas wells is still taken as q. g Taking production time dt as an example, the anti-condensation effect caused by formation pressure drop dP offsets the net outflow of condensate oil, resulting in an increase in condensate oil saturation dS within the unit pore volume. o Therefore, the increased volume of condensate oil is V. o1 :

[0081] V o1 =2πrhφdrdS o …………………………………………(10)

[0082] On the other hand, due to the anti-condensation effect caused by the formation pressure drop dP in the formation, the concentration of condensate oil in the gas phase per unit gas decreases by dC. Considering the net outflow of condensate oil, therefore, with a stable gas flow rate q... g During the production time dt, the volume of condensate oil reduced is V. o2 :

[0083] V o2 =q g dtdC-V o3 ………………………………………………(11)

[0084] Among them, the net outflow volume V of condensate oil o3 for:

[0085]

[0086] S126. Based on the increase and decrease in condensate oil volume under the condensation action and the net outflow volume of condensate oil, determine the dynamic saturation formation rate of condensate oil in the anti-condensation process.

[0087] Furthermore, based on the increase and decrease in condensate oil volume under the condensation action and the net outflow volume of condensate oil, the dynamic saturation formation rate of the condensate oil during the anti-condensation process is determined as follows:

[0088] According to the following formula:

[0089] V o1 =2πrhφdrdS o ',

[0090] V o2 =q g dtdC-V o3 ,

[0091]

[0092] V o1 =V o2 ,

[0093] Determine the dynamic saturation formation rate of the condensate oil during the anti-condensation process.

[0094] Among them, V o1 V represents the increase in condensate oil volume during the anti-condensation process; o2 V represents the reduction in condensate oil volume during the anti-condensation process; o3 The net outflow volume of condensate oil during the reverse condensation process is represented by r; the well control radius of the gas well is represented by h; the effective thickness of the condensate gas reservoir is represented by Φ; and the porosity of the condensate gas reservoir is represented by S. o ' represents the dynamic saturation of condensate oil; C represents the concentration of condensate oil present in the gas phase; μ g P represents the viscosity of the gas phase. sc Z represents the standard surface pressure; T represents the gas deviation coefficient; y represents the temperature of the condensate reservoir; μ represents the anti-condensation factor; o K represents the viscosity of the condensate oil; K represents the effective permeability of the condensate gas reservoir; K rg P represents the relative permeability of the gas. r T represents the formation pressure at the well control radius; sc Indicates the standard ground temperature; K ro This indicates the relative permeability of the oil phase.

[0095] Specifically, substituting formula (12) in step S125 into formula (11) yields the reduced condensate oil volume V. o2 :

[0096]

[0097] Since the decrease in the volume of condensate oil in the gas should be equal to the increase in the volume of condensate oil per unit volume, we can conclude that:

[0098]

[0099] Solving equation (14) yields the rate of dynamic saturation formation of condensate oil during the anti-condensation process. The expression is:

[0100]

[0101] This invention, through the aforementioned method, determines the dynamic saturation formation rate of condensate oil, enabling engineers and geologists to more accurately predict the behavior of condensate gas reservoirs at different development stages. This facilitates the development of more rational strategies, such as determining optimal extraction rates and gas injection volumes, thereby improving condensate oil recovery. The dynamic saturation formation rate can also be used to predict reservoir productivity changes under different pressure and temperature conditions, providing crucial information for production scheduling and capacity planning. In summary, these advantages not only contribute to improving condensate oil recovery and economic efficiency but also help reduce development risks and ensure the safe and stable development of gas reservoirs.

[0102] S127. Determine the dynamic saturation of the condensate oil based on the dynamic saturation formation rate of the condensate oil during the anti-condensation process.

[0103] Furthermore, the dynamic saturation S of the condensate oil is determined based on the dynamic saturation formation rate of the condensate oil during the anti-condensation process and the following formula. o ':

[0104]

[0105] B g This represents the volume coefficient of the condensate gas.

[0106] Specifically, by substituting equations (6) and (7) into equation (15), separating the variables, integrating, and solving, the dynamic saturation S of the condensate oil during the anti-condensation process can be obtained. o The expression for ' is:

[0107]

[0108] The dynamic saturation of condensate oil is an important parameter reflecting its flow capacity in the formation. By monitoring and analyzing the changes in dynamic saturation, the flow capacity of condensate oil at different development stages can be accurately predicted, thereby enabling the formulation of reasonable extraction strategies.

[0109] S13. Based on the dynamic saturation of the condensate oil and the equivalent production time, determine the radius of the flow equilibrium point when the condensate oil in the condensate gas reservoir is released.

[0110] Further, based on the dynamic saturation of the condensate oil and the equivalent production time, determining the flow equilibrium point radius at the time of condensate oil precipitation in the condensate gas reservoir includes: determining the flow equilibrium point radius r(t) at the time of condensate oil precipitation in the condensate gas reservoir based on the dynamic saturation of the condensate oil, the equivalent production time, and the following formula:

[0111]

[0112] K ro ′ represents the relative permeability of the oil phase.

[0113] Specifically, by differentiating the time in equation (16), and through differential calculation and simplification, we can obtain the expression r(t) for the flow equilibrium point radius during the condensate oil precipitation process in the anti-condensation process. In this formula, r(t) indicates that the flow equilibrium point radius changes with the mining time.

[0114] The embodiments provided by this invention quantify the formation time of critical dynamic saturation of condensate oil during the reverse condensation process based on the static saturation formation rate and static saturation of condensate oil; then quantify the formation rate of dynamic saturation of condensate oil during the reverse condensation process, calculate the dynamic saturation of condensate oil and its changes during the reverse condensation process, and finally determine the radius of the flow equilibrium point when condensate oil is separated during the reverse condensation process. This solves the technical problem in the field of being unable to determine the radius of the flow equilibrium point when condensate oil is separated in condensate gas reservoirs, and realizes a quantitative description of the radius of the flow equilibrium point when condensate oil is separated at different development stages of condensate gas reservoirs. This has important practical significance for understanding the seepage law of condensate gas reservoirs and provides an important basis for efficient and targeted control strategies.

[0115] To provide a more intuitive understanding of the technique and method for determining the distribution radius of condensate oil in a condensate gas reservoir provided in Example 1, the specific implementation and application of this invention will be illustrated using a phased characteristic method diagnostic evaluation scheme for a condensate gas reservoir in an actual oilfield in my country that employs the above method.

[0116] This condensate gas reservoir has a simple structure, mainly composed of anticlines, generally trending NNE, and is divided by a series of early NNE-trending reverse faults and later near-EW-trending normal faults. Horizontally, the gas reservoir is enriched in structural highs, while vertically it consists of multiple gas reservoirs with several independent gas-water systems, at depths of 2300–3500 m. It is a medium-low porosity, medium-low permeability reservoir, with reservoir properties deteriorating with increasing depth. Condensate oil content is 50–150 g / m³. 3 It is a low- to medium-content condensate oil and condensate gas reservoir. The normal temperature and pressure system has an original formation pressure of 25–34 MPa and a dew point pressure of 23–38 MPa. The formation pressure in the middle of the gas reservoir is mostly lower than the reservoir dew point pressure, and the formation is generally in a saturated state.

[0117] Well No. 1 has medium to high productivity, is located in a structurally high position, has an average porosity of 13%, an average permeability of 31 mD, a reservoir thickness of 50 m, and a condensate oil content of 81 g / m³. 3 The well began production in November 2011, and its production dynamics curve is as follows: Figure 4 As shown in the figure. The horizontal axis represents a specific moment t from the start of production to the present (or a future) day.

[0118] The method described in this invention was used to obtain the variation law of the flow equilibrium point radius over time during the precipitation of typical No. 1 condensate oil. See the specific reference below. Figure 5 The horizontal axis represents a moment t from the start of production to a certain point in time (or in the future), and the vertical axis represents the radius r(t) of the flow equilibrium point when condensate oil is separated.

[0119] Well No. 2 is a typical high-yield well. Located in the high part of the structure, it has an average porosity of 14%, an average permeability of 25 mD, a reservoir thickness of 23 m, and a condensate oil content of 68 g / m³. 3 The well began production in January 2011, and its production dynamics curve is as follows: Figure 6 As shown.

[0120] The method described in this invention was used to obtain the variation law of condensate oil distribution radius over time in a typical well No. 2, as follows: Figure 7 As shown.

[0121] Well No. 3 exhibits high initial productivity, but low productivity after three years. Located in a high-lying part of the geological structure, it has an average porosity of 15%, an average permeability of 54 mD, a reservoir thickness of 31 m, and a condensate oil content of 215 g / m³. 3 The well began production in February 2012, and its production dynamics curve is as follows: Figure 8 As shown.

[0122] The method described in this invention was used to obtain the variation law of condensate oil distribution radius over time in a typical well No. 3, as follows: Figure 9 As shown.

[0123] On the other hand, such asFigure 10 This is a structural diagram of a system for determining the radius of the flow equilibrium point when condensate oil is separated, provided in an embodiment of the present invention. This invention also provides a system for determining the radius of the flow equilibrium point when condensate oil separates. The system 10 includes: a first determining module 101, used to determine the equivalent production time of a gas well based on its production parameters, wherein the production parameters include a well control radius, an equivalent gas production rate corresponding to the wellbore radius, and a stable gas production rate, and the equivalent production time of the gas well is related to the well control radius; a second determining module 102, used to determine the static saturation and dynamic saturation of the condensate oil based on the stable gas production rate of the gas well, the equivalent production time of the gas well, and physical parameters during the reverse condensation process, wherein the static saturation and dynamic saturation of the condensate oil are related to the equivalent production time; and a third determining module 103, used to determine the radius of the flow equilibrium point when condensate oil separates from the condensate gas reservoir based on the dynamic saturation of the condensate oil and the equivalent production time.

[0124] The method and effects of the system for determining the radius of the flow equilibrium point when condensate oil separates in the embodiments of the present invention are the same as those in the above-described method embodiments, and will not be repeated here.

[0125] Further, the first determining module 101 is used to determine the equivalent production time of the gas well based on the gas well's production parameters, including: determining the equivalent production time t of the gas well based on the well control radius, the equivalent gas production and stable gas production corresponding to the wellbore radius, and the following formula:

[0126]

[0127] Among them, Q p P represents the elastic gas production of a gas well within the well control area. i Indicates the original formation pressure; The value of Q represents the average formation pressure within the well control area; r represents the well control radius of the gas well; e This indicates the displacement gas supply from gas wells outside the well control area; r e Q represents the distance from the well point to the boundary of the condensate gas reservoir; r (r) represents the equivalent gas production of the gas well; q g This indicates the stable gas production of a gas well.

[0128] In another aspect, embodiments of the present invention also provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the method for determining the radius of the flow equilibrium point during condensate oil precipitation as described above.

[0129] In another aspect, embodiments of the present invention also provide a computer program product, which, when executed by a processor, implements the method for determining the radius of the flow equilibrium point when condensate oil is separated, as described above.

[0130] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can 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, etc.) containing computer-usable program code.

[0131] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can 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, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0132] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0133] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0134] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0135] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0136] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0137] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0138] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for determining the radius of the flow equilibrium point during condensate oil precipitation, characterized in that, The method includes: Based on the production parameters of the gas well, the equivalent production time of the gas well is determined, wherein the production parameters of the gas well include the well control radius, the equivalent gas production corresponding to the well radius, and the stable gas production, and the equivalent production time of the gas well is related to the well control radius; Based on the stable gas production of the gas well, the equivalent production time of the gas well, and the physical parameters during the reverse condensation process, the static saturation and dynamic saturation of the condensate oil are determined, wherein the static saturation and dynamic saturation of the condensate oil are related to the equivalent production time; and Based on the dynamic saturation of the condensate oil and the equivalent production time, the radius of the flow equilibrium point when the condensate oil in the condensate gas reservoir is precipitated is determined.

2. The method according to claim 1, characterized in that, The determination of the equivalent production time of the gas well based on its production parameters includes: Based on the well control radius, the equivalent gas production rate and stable gas production rate corresponding to the wellbore radius, and the following formula, the equivalent production time t of the gas well is determined: Among them, Q p P represents the elastic gas production of a gas well within the well control area. i The original formation pressure is represented by P; the average formation pressure within the well control area is represented by r; and the well control radius of the gas well is represented by Q. e This indicates the displacement gas supply from gas wells outside the well control area; r e Q represents the distance from the well point to the boundary of the condensate gas reservoir; r (r) represents the equivalent gas production of the gas well; q g This indicates the stable gas production of a gas well.

3. The method according to claim 1, characterized in that, The physical parameters include formation pressure drop, the increase in condensate oil saturation per unit pore volume during reverse condensation, and the decrease in the concentration of condensate oil in the gas phase per unit gas. Based on the stable gas production of the gas well, the equivalent production time of the gas well, and the physical parameters in the reverse condensation process, the static saturation of the condensate oil is determined by: Based on the stable gas production of the gas well, the equivalent production time of the gas well, the formation pressure drop during the reverse condensation process, the increase in condensate oil saturation per unit pore volume during the reverse condensation process and the decrease in the concentration of condensate oil in the gas phase per unit gas, the static saturation formation rate of the condensate oil is determined. The static saturation of the condensate oil is determined based on the static saturation formation rate of the condensate oil, the stable gas production of the gas well, and the volume coefficient of the condensate gas.

4. The method according to claim 3, characterized in that, Based on the stable gas production of the gas well and the physical parameters during the reverse condensation process, the dynamic saturation of the condensate oil is determined by: Based on the stable gas production of the gas well, the equivalent production time of the gas well, the formation pressure drop and the reduction in condensate concentration during the reverse condensation process, the increase and decrease in condensate volume under the condensation action and the net outflow volume of condensate are determined. The dynamic saturation formation rate of condensate oil during the anti-condensation process is determined based on the increase and decrease in condensate oil volume under the condensation action and the net outflow volume of condensate oil. The dynamic saturation of the condensate oil is determined based on the rate of formation of dynamic saturation of the condensate oil during the anti-condensation process.

5. The method according to claim 4, characterized in that, The dynamic saturation formation rate of the condensate oil during the anti-condensation process is determined based on the increase and decrease in condensate oil volume under the condensation action and the net outflow volume of the condensate oil, including: According to the following formula: V o1 =2πrhφdrdS o ', V o2 =q g dtdC-V o3 , V o1 =V o2 , Determine the dynamic saturation formation rate of the condensate oil during the anti-condensation process. Among them, V o1 V represents the increase in condensate oil volume during the anti-condensation process; o2 V represents the reduction in condensate oil volume during the anti-condensation process; o3 The net outflow volume of condensate oil during the reverse condensation process is represented by r; the well control radius of the gas well is represented by h; the effective thickness of the condensate gas reservoir is represented by Φ; and the porosity of the condensate gas reservoir is represented by S. o ' represents the dynamic saturation of condensate oil; C represents the concentration of condensate oil present in the gas phase; μ g P represents the viscosity of the gas phase. sc Z represents the standard surface pressure; T represents the gas deviation coefficient; y represents the temperature of the condensate reservoir; μ represents the anti-condensation factor; o K represents the viscosity of the condensate oil; K represents the effective permeability of the condensate gas reservoir; K rg P represents the relative permeability of the gas. r T represents the formation pressure at the well control radius; sc Indicates the standard ground temperature; K ro This indicates the relative permeability of the oil phase.

6. The method according to claim 5, characterized in that, The determination of the dynamic saturation of the condensate oil based on the formation rate of dynamic saturation of the condensate oil during the anti-condensation process includes: The dynamic saturation S of the condensate oil is determined based on the dynamic saturation formation rate of the condensate oil during the anti-condensation process and the following formula. o ': B g This represents the volume coefficient of the condensate gas.

7. The method according to claim 6, characterized in that, Based on the dynamic saturation of the condensate oil and the equivalent production time, the radius of the flow equilibrium point at which the condensate oil precipitates from the condensate gas reservoir is determined, including: Based on the dynamic saturation of the condensate oil, the equivalent production time, and the following formula, the radius r(t) of the flow equilibrium point when the condensate oil in the condensate gas reservoir is released is determined: K ro ′ represents the relative permeability of the oil phase.

8. The method according to claim 1, characterized in that, The method further includes: determining the critical dynamic saturation formation time of the condensate oil in the anti-condensation process based on the static saturation of the condensate oil and the critical saturation of the condensate oil in the anti-condensation process.

9. A system for determining the radius of the flow equilibrium point during condensate oil precipitation, characterized in that, The system includes: The first determining module is used to determine the equivalent production time of the gas well based on the production parameters of the gas well, wherein the production parameters of the gas well include the well control radius, the equivalent gas production corresponding to the well radius, and the stable gas production, and the equivalent production time of the gas well is related to the well control radius; The second determining module is used to determine the static saturation and dynamic saturation of the condensate oil based on the stable gas production of the gas well, the equivalent production time of the gas well, and the physical parameters during the reverse condensation process, wherein the static saturation and dynamic saturation of the condensate oil are related to the equivalent production time; and The third determining module is used to determine the radius of the flow equilibrium point when condensate oil is separated from the condensate gas reservoir, based on the dynamic saturation of the condensate oil and the equivalent production time.

10. The system according to claim 9, characterized in that, The first determining module is used to determine the equivalent production time of the gas well based on its production parameters, including: Based on the well control radius, the equivalent gas production rate and stable gas production rate corresponding to the wellbore radius, and the following formula, the equivalent production time t of the gas well is determined: Among them, Q p P represents the elastic gas production of a gas well within the well control area. i The original formation pressure is represented by P; the average formation pressure within the well control area is represented by r; and the well control radius of the gas well is represented by Q. e This indicates the displacement gas supply from gas wells outside the well control area; r e Q represents the distance from the well point to the boundary of the condensate gas reservoir; r (r) represents the equivalent gas production of the gas well; q g This indicates the stable gas production of a gas well.

11. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method for determining the radius of the flow equilibrium point during condensate oil precipitation as described in any one of claims 1-8.

12. A computer program product, characterized in that, When executed by a processor, the computer program implements the method for determining the radius of the flow equilibrium point during condensate oil precipitation as described in any one of claims 1-8.

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