Quantitative characterization method and system for oil and gas transport efficiency of sandstone lateral migration channel

Abstract

The invention provides a quantitative characterization method and a quantitative characterization system for oil and gas transport efficiency of a sandstone lateral migration channel, and the method comprises the steps: obtaining a contour line included angle and a target stratum inclination angle of each well position at two sides of a construction ridge or valley according to a target stratum top surface construction contour map, and constructing a construction ridge or valley transport index according to the contour line included angle; buoyancy borne by the target stratum of each well position is obtained according to the target stratum dip angle; obtaining the residual pressure difference gradient of each well position according to the target layer pressure plane distribution diagram; superposing the contour map of the top surface structure of the target stratum and the pressure plane distribution map to obtain an included angle between an inclined reverse extension line and a residual pressure difference gradient direction in the target stratum of each well position; obtaining the weighted average permeability and the porosity of the target layer of each well location, the ridge or valley construction conduction index of each well location, the buoyancy borne by the target layer, the residual pressure difference gradient and the included angle to construct comprehensive evaluation indexes of each well location; and quantitatively characterizing the oil and gas transport efficiency of the sandstone lateral migration channel by using the comprehensive evaluation indexes of each well location. According to the invention, the lateral conduction channel conduction efficiency can be evaluated visually, simply and conveniently.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas geological exploration, and particularly relates to a method and system for quantitatively characterizing the oil and gas conduction efficiency of a sandstone lateral migration channel (including a conduction layer and an unconformity). Background Art

[0002] The migration and accumulation of oil and gas are a key link in the hydrocarbon accumulation process. The conduction capacity of the conduction system controls whether oil and gas can accumulate in the trap, the range and quantity of the accumulated oil and gas, and has a significant impact on improving the exploration success rate. The sand body-unconformity lateral conduction channel is very important in the research of the conduction system, especially in the conduction system mainly dominated by lateral migration.

[0003] Both the sandstone conduction layer and the overlying unconformity use connected pores and locally developed fractures as the microscopic channels for oil and gas migration, and the conduction channel can essentially be regarded as a sandstone conduction layer modified by weathering, and the two can be studied together.

[0004] At present, the quantitative evaluation methods for the physical properties and geometric connectivity of sand bodies are relatively mature, and there are also qualitative evaluation methods such as tracers and well test measurements for hydrodynamic connectivity. The two-dimensional and three-dimensional characterization technologies for the distribution of sand bodies are also becoming increasingly mature. However, the secondary migration of oil and gas through the sandstone conduction layer is often jointly controlled by various factors, especially by the connectivity and physical properties of the sand body. In the study of the conduction capacity of the sandstone conduction layer, the influence of various factors should be comprehensively considered. The existing quantitative evaluation methods for the conduction efficiency of the lateral conduction channel have the following deficiencies:

[0005] Most of the evaluation methods for conduction efficiency lack the consideration of hydrodynamic connectivity and the effective migration path of oil and gas, resulting in difficulty in guiding exploration and development in the underground where the geological conditions and dynamic conditions are very complex.

[0006] Most of the existing methods for comprehensively evaluating the conduction efficiency by combining various conduction elements are not easy to operate, require high geological data, have a narrow applicability, or the evaluation results highly depend on the professional level of the evaluator, and are difficult to apply. Summary of the Invention

[0007] In order to solve the problems existing in the prior art, the present invention provides a method and system for quantitatively characterizing the oil and gas conduction efficiency of a sandstone lateral migration channel. Starting from the oil and gas display location, the dynamic factors and geological factors of conduction are combined, solving the problems of insufficient consideration of the oil and gas migration channel and the multi-solution of the evaluation results in the previous evaluation methods, and having important significance in intuitively and simply evaluating the conduction efficiency of the lateral conduction channel and optimizing favorable exploration areas.

[0008] To achieve the above object, the present invention provides the following technical solution: A method for quantitatively characterizing the oil and gas conduction efficiency of a sandstone lateral migration channel, the specific steps are as follows:

[0009] S1 Obtain the included angle θ of the isopach lines on both sides of the structural ridge or valley and the dip angle β of the target layer at each well location according to the structural isopach map of the top surface of the target layer, and construct the transport index λ of the structural ridge or valley according to the included angle θ of the isopach lines on both sides of the structural ridge or valley s , and obtain the buoyancy F1 received by the target layer at each well location according to the dip angle β of the target layer at each well location;

[0010] S2 Obtain the remaining pressure difference gradient F2 at each well location according to the pressure plane distribution map of the target layer;

[0011] S3 Superimpose the structural isopach map of the top surface of the target layer and the pressure plane distribution map to obtain the included angle a between the reverse extension line of the dip direction and the direction pointed by the remaining pressure difference gradient in the target layer at each well location;

[0012] S4 Obtain the weighted average permeability and weighted average porosity of the oil and gas showing intervals of the target layer at each well location, and combine the transport index λ of the structural ridge or valley at each well location s , the buoyancy F1 received by the target layer at each well location, the remaining pressure difference gradient F2 and the included angle a to construct the comprehensive evaluation index λ at each well location;

[0013] S5 Use the comprehensive evaluation index λ at each well location to quantitatively characterize the oil and gas transport efficiency of the sandstone lateral migration channel. The higher the value of the comprehensive evaluation index λ, the higher the transport efficiency.

[0014] Further, in S1, the structural isopach map of the top surface of the target layer is obtained by correcting the elevation of the seismic reflection layer on the top surface of the target layer with the elevation of the top surface of the target layer of a single well;

[0015] In S2, the pressure plane distribution map is obtained by interpolating the formation pressure data of the drill pipe test of the target layer of a single well between wells;

[0016] In S4, the porosity is obtained by the theoretical formula of logging porosity or by fitting the logging curve and the measured porosity;

[0017] The permeability is obtained by fitting the porosity, the shale content obtained from the natural gamma logging curve and the measured permeability value of the core.

[0018] Further, in S1, the transport index λ of the structural ridge or valley s is obtained according to the following formula:

[0019]

[0020] In the formula, θ is the included angle of the isopach lines on both sides of the structural ridge or valley, and the unit is °; m is a dimensionless number, m = -1 for the structural ridge or monoclinic plane, and m = 1 for the structural valley.

[0021] Further, in S1, if the well point is on the structural ridge, take the dip angle of the structural ridge as the dip angle value of this point; if the well point is inside the anticlinal trap, take the dip angle of the slope in the source direction of the trap as the dip angle value of this point.

[0022] Further, in S1, the buoyancy force is obtained according to the following formula:

[0023] F1 = (ρ w - ρ o ) * g * sinβ

[0024] In the formula: ρ w is the density of water, with the unit of kg / m 3 ;

[0025] ρ o is the density of oil and gas, with the unit of kg / m 3 ;

[0026] g is the acceleration of gravity, with the unit of m / s 2 ;

[0027] β is the dip angle of the target layer, with the unit of °.

[0028] Further, in S2, the remaining pressure difference gradient F2 is obtained according to the following formula:

[0029]

[0030] In the formula: ΔP is the difference in remaining pressure between two isopachs, with the unit of Pa; ΔL is the distance between two isopachs, with the unit of m.

[0031] Further, in S4, the calculation formula of the comprehensive evaluation index λ is as follows:

[0032]

[0033] F1 = (ρ w - ρ o ) * g * sinβ

[0034]

[0035] In the formula: θ is the included angle between the isopachs on both sides of the structural ridge or valley, with the unit of °; m is a dimensionless number, m = -1 for the structural ridge or monoclinic plane, and m = 1 for the structural valley; K i is the weighted average permeability of the i-th layer of the oil and gas showing interval in a single well, with the unit of md; φ i is the weighted average porosity of the i-th layer of the oil and gas showing interval in a single well, dimensionless; h i$h_i$ is the thickness of the $i$-th layer of hydrocarbon display section in a single well, with the unit of m; $h$ is the total thickness of the hydrocarbon display section in a single well, with the unit of m; $\mu$ is the dynamic viscosity of the hydrocarbon, with the unit of mPa·s; $\alpha$ is the angle between the direction of hydrocarbon buoyancy and the direction of hydrodynamic force, with the unit of °; $\rho$ w is the density of water, with the unit of kg / m 3 ; $\rho$ o is the density of the hydrocarbon, with the unit of kg / m 3 ; $g$ is the acceleration due to gravity, with the unit of m / s 2 ; $\beta$ is the dip angle of the target layer, with the unit of °; $\Delta P$ is the difference in residual pressure between two isobars in the pressure plan of the target layer, taking positive values, with the unit of Pa; $\Delta L$ is the distance between two isobars in the pressure plan of the target layer, with the unit of m.

[0036] Further, in S4, an automatic viscosity and density analyzer is used to test the physical properties of the hydrocarbon to obtain the density and dynamic viscosity of the hydrocarbon.

[0037] Further, the comprehensive evaluation index $\lambda$ of each well location is marked on the structural isobar map of the top surface of the target layer or the base map of the study area work area with the marks of hydrocarbon accumulation / failure wells in the target layer to obtain the $\lambda$ plane isobar map. The high-value area of the comprehensive evaluation index $\lambda$ in the $\lambda$ plane isobar map is the high-value area of the hydrocarbon transport efficiency in the migration channel.

[0038] The present invention also provides a method for determining a favorable hydrocarbon accumulation area zone. The high-value area of the hydrocarbon transport efficiency in the migration channel is determined by using the above-mentioned quantitative characterization method for the hydrocarbon transport efficiency of the lateral migration channel in sandstone, and the favorable hydrocarbon accumulation area zone is obtained by combining the structural isobar map of the top surface of the target layer in the study area and the trap distribution.

[0039] The present invention also provides a system for running the above-mentioned quantitative characterization of the hydrocarbon transport efficiency of the lateral migration channel in sandstone, including:

[0040] A ridge or valley transport index and buoyancy data acquisition module, which is used to obtain the included angle $\theta$ between the isobars on both sides of the structural ridge or valley and the dip angle $\beta$ of the target layer of each well location according to the structural isobar map of the top surface of the target layer, and construct the structural ridge or valley transport index $\lambda$ according to the included angle $\theta$ between the isobars on both sides of the structural ridge or valley s , and obtain the buoyancy $F_1$ received by the target layer of each well location according to the dip angle $\beta$ of the target layer of each well location;

[0041] A remaining pressure difference gradient data acquisition module for each well location, which is used to obtain the remaining pressure difference gradient $F_2$ of each well location according to the pressure plane distribution map of the target layer;

[0042] An included angle data acquisition module, which is used to overlay the structural isobar map of the top surface of the target layer and the pressure plane distribution map to obtain the included angle $\alpha$ between the reverse extension line of the dip direction and the direction of the remaining pressure difference gradient in the target layer of each well location;

[0043] The comprehensive evaluation index construction module is used to obtain the weighted average permeability and weighted average porosity of the oil and gas display intervals of the target layers at each well location, and combine the ridge or valley transport index λ at each well location s 、the buoyancy F1, the remaining pressure difference gradient F2 and the included angle a received by the target layer at each well location to construct the comprehensive evaluation index λ for each well location;

[0044] The oil and gas transport efficiency characterization module is used to quantitatively characterize the oil and gas transport efficiency of the sandstone lateral migration channels by using the comprehensive evaluation index λ of each well location. The higher the value of the comprehensive evaluation index λ, the higher the transport efficiency.

[0045] Compared with the prior art, the present invention has at least the following beneficial effects:

[0046] The present invention provides a method for quantitatively characterizing the oil and gas transport efficiency of sandstone lateral migration channels. Starting from the actual migration channels of oil and gas in the transport layer, using the equivalent porosity of the oil and gas display intervals to represent the cross-sectional area of the transport layer, instead of the current most evaluation methods that start from the transport layer itself regardless of whether oil and gas migration has occurred, and taking into account both the geological factors and dynamic factors affecting the lateral migration of oil and gas in the transport layer. According to the trend that oil and gas preferentially migrate along the structural ridge and are difficult to migrate along the structural valley, a ridge or valley evaluation index is established. Using the resultant force of the remaining pressure gradient and buoyancy as the transport driving force, based on Darcy's law, a comprehensive evaluation index λ of the transport efficiency of the sandstone transport layer at each well location is obtained. The evaluation result is consistent with the actual flow rate of the transport layer, rather than the usual evaluation methods which are just simple combinations of evaluation parameters, having practical geological significance, and the application results are more indicative, and can be reasonably extrapolated to other similar oil and gas bearing basins, specifically solving the problems of incomplete consideration of influencing factors and limited application scope in the current evaluation methods; at the same time, the formula is simple and easy to understand, and the required parameters are all obtained from conventional exploration data, without parameters that require artificial assignment, and are all objective and unique data, effectively solving the problems of cumbersome steps, high cost and strong subjectivity of the current evaluation methods. Description of the Drawings

[0047] Figure 1 It is a flow chart of the method for quantitatively characterizing the oil and gas transport efficiency of the sandstone lateral migration channels of the present invention.

[0048] Figure 2 It is a plane distribution map of the comprehensive evaluation index λ and the effective transport area of a specific embodiment of the present invention.

[0049] Figure 3 It is the evaluation result of the transport efficiency of the favorable convergence well area in a specific embodiment of the present invention. Detailed Embodiments

[0050] The present invention will be further described below in conjunction with the drawings and specific embodiments.

[0051] Darcy's law is mainly used to indicate the ability of a porous medium to pass a fluid. The greater the flow rate, the stronger the passing ability. Therefore, it can also be used to characterize the efficiency of underground sandstone in transporting oil and gas. Darcy's law states that when a fluid passes through a sand column, its flow rate is proportional to the cross-sectional area of the sand column and the pressure difference between the inlet and outlet ends, and inversely proportional to the length of the sand column and the viscosity of the fluid itself. It is expressed in the form of an equation as follows:

[0052]

[0053] In the formula: Q is the flow rate through the sand column, with the unit of cm 3 / s;

[0054] A is the cross-sectional area of the sand column, with the unit of cm 2 ;

[0055] L is the length of the sand column, with the unit of cm;

[0056] μ is the viscosity of the fluid passing through the sand column, with the unit of mPa·s;

[0057] Δ P is the pressure difference before and after the fluid passes through the sand column, with the unit of pa;

[0058] K is the permeability, with the unit of md.

[0059] The permeability of the conducting layer is expressed by the equivalent permeability of the oil and gas showing interval (the weighted average permeability of the oil and gas bearing intervals); because the migration of oil and gas underground does not occur in a piston-like manner filling the entire conducting layer like groundwater, but only migrates preferentially in the 1% - 10% advantageous space of the conducting layer, the macroscopic cross-sectional area of the conducting layer does not affect the conduction efficiency. The equivalent porosity of the oil and gas showing interval (the weighted average porosity of the oil and gas bearing intervals), which can better indicate the relative range of oil and gas migration, is used to represent the cross-sectional area of the conducting layer;

[0060] In Darcy's law Δ P / L is the fluid pressure gradient, indicating the magnitude of the fluid migration driving force. Considering that the main driving forces for oil and gas migration are buoyancy, residual pressure gradient, and capillary force, and the capillary force acting on the migration of oil and gas in the sandstone layer can be ignored compared to the other two forces, the resultant force of the residual pressure gradient and buoyancy is used as the conduction driving force.

[0061] Finally, considering the tendency that oil and gas prefer to migrate along the structural ridge and are difficult to migrate along the structural valley, a structural ridge or valley evaluation index is innovatively introduced, and finally a comprehensive evaluation formula for the conduction efficiency of the sandstone conducting layer is obtained, which can judge the advantageous migration channels of oil and gas and thus predict the favorable oil and gas accumulation areas.

[0062] The present invention comprehensively considers the physical properties of the oil and gas showing intervals, the physical properties of the crude oil, the occurrence of the conducting layer, and the external dynamic action, takes a single well as the basic evaluation unit, and takes the oil and gas showing intervals as the effective conducting layer;

[0063] As Figure 1 shown, the present invention provides a method for quantitatively characterizing the oil and gas conduction efficiency of the lateral migration channels in sandstone. The Darcy's law of percolation is modified according to the influencing factors of oil and gas migration to obtain a comprehensive evaluation index λ. The specific steps are as follows:

[0064] Step 1: Determine the horizons and distribution ranges of the main conduction layers in the study area, and select typical wells drilled to these horizons for data collection.

[0065] The selected wells are first required to have a wide enough distribution range to cover the study area as much as possible; secondly, wells that completely penetrate the target layer are preferably selected. If the well data is not sufficient to cover the work area, wells that do not penetrate the target layer but have oil and gas shows are considered. Wells that do not penetrate the target layer and have no oil and gas shows cannot be selected as the research objects.

[0066] Step 2: Statistically analyze the single-layer thickness and total thickness of the oil and gas show intervals in each well.

[0067] The oil and gas show horizons can be comprehensively judged from gas logging, cuttings, fluorescence logging data, core data, and logging data and obtained after depth correction.

[0068] Step 3: Calculate the weighted average porosity and permeability of the oil and gas show intervals in each well.

[0069] The porosity is obtained through the theoretical formula of logging porosity. If the core physical property data of the target layer is sufficient, it can also be calculated by the formula obtained from the fitting of the logging curve and the measured porosity.

[0070] The permeability is calculated by the formula obtained from the fitting of the porosity, the shale content obtained from the natural gamma logging curve, and the core measured permeability value. The higher the porosity and permeability values, the stronger the oil and gas conduction ability of the conduction layer.

[0071] Step 4: Test the physical properties of oil and gas through an automatic viscosity and density measuring instrument to obtain the density and dynamic viscosity of the oil and gas.

[0072] For wells without physical property test data, the values of adjacent wells are taken.

[0073] If the test data is distorted due to the mixing of oil and gas in the conduction layer, the data of the in-source oil and gas reservoir is used as the unified value for each well. The driving force of oil and gas migration decreases with the increase of density and viscosity.

[0074] Step 5: If the well point is located on a structural ridge or a structural valley, obtain the structural contour map of the top surface of the target layer, and calculate the included angle θ between the contour lines on both sides of the structural ridge or valley for each well position located on the structural ridge or valley;

[0075] Preferably, the structural contour map of the top surface is obtained by correcting the elevation of the seismic reflection layer on the top surface of the target layer with the elevation of the top surface of the target layer of a single well.

[0076] The conduction index λ of the structural ridge or valleys Obtained according to the following formula:

[0077]

[0078] Where θ is the included angle between the isopleths on both sides of the structural ridge or valley, with the unit of ° (for a monoclinic plane, there is no included angle, i.e., the value is 180°); m is a dimensionless number, m = -1 for a structural ridge or monoclinic plane, and m = 1 for a structural valley.

[0079] Among them, the smaller the included angle of the isopleths of the structural ridge, the stronger the ability to converge oil and gas, and the larger the included angle of the isopleths of the structural valley, the stronger the ability to diverge oil and gas.

[0080] Step Six: Obtain the dip angle β of the target layer at each well location through the structural isopleth map of the top surface of the target layer. The larger the dip angle, the greater the buoyancy force received, and the greater the buoyancy force, the stronger the migration driving force. Calculate the buoyancy force received by the target layer at each well location according to the dip angle β of the target layer. The buoyancy force is obtained according to the following formula:

[0081] F1 = (ρ w - ρ o ) * g * sinβ

[0082] Where: ρ w is the density of water, with the unit of kg / m 3 ;

[0083] ρ o is the density of oil and gas, with the unit of kg / m 3 ;

[0084] g is the acceleration due to gravity, with the unit of m / s 2 ;

[0085] β is the dip angle of the target layer, with the unit of °.

[0086] Among them, if the well point is on the structural ridge, take the dip angle of the structural ridge as the dip angle value β at this point; if the well point is inside the anticlinal trap, take the slope dip angle in the source direction of the trap as the dip angle value β at this point.

[0087] Step Seven: If the target layer is located in the overpressure zone, obtain the remaining pressure difference gradient at each well location through the plane distribution map of the target layer pressure or pressure coefficient, pointing to the direction of decreasing remaining pressure, that is, the direction of weakening hydrodynamic force, representing the direction of hydrodynamic force. The remaining pressure difference gradient F2 is obtained according to the following formula:

[0088]

[0089] Where ΔP is the difference in remaining pressure between two isopleths, with the unit of Pa;

[0090] ΔL is the distance between two isopleths, with the unit of m.

[0091] Preferably, the pressure plane distribution map is obtained by interpolating the formation pressure data of the drill pipe test of the target layer of a single well between wells.

[0092] Specifically, the greater the gradient of the remaining pressure difference along the oil and gas migration direction, the stronger the tectonic or hydrodynamic action.

[0093] Step Eight: Under the conditions of Step Seven, overlay the structural contour map of the top surface of the target layer and the pressure coefficient plan of the target layer, and calculate the included angle between the reverse extension line of the target layer dip at each well position and the direction of the remaining pressure difference gradient, that is, the included angle a between the direction of increasing buoyancy force on the oil and gas and the hydrodynamic direction. The smaller the included angle value, the stronger the oil and gas migration force.

[0094] Step Nine: According to the tectonic ridge or valley conduction index λ s and the buoyancy force F1, the remaining pressure difference gradient F2, the equivalent porosity, and the equivalent permeability of the target layer at each well position, the comprehensive evaluation index λ of the structure:

[0095] The comprehensive evaluation index λ is intended to comprehensively evaluate the conduction efficiency of the channel by using various indexes that affect the conduction efficiency of the migration channel. The larger the λ value, the higher the conduction efficiency of the channel. The relationship between the actual oil and gas accumulation situation and the λ value can be combined to judge that when λ exceeds a certain value, it is the dominant oil and gas migration channel. The calculation formula of the comprehensive evaluation index λ is as follows:

[0096]

[0097]

[0098] In the formula, θ is the included angle between the contour lines on both sides of the tectonic ridge or valley, and the unit is ° (the monoclinic plane has no included angle, that is, the value is 180°);

[0099] m is a dimensionless number, m = -1 for the tectonic ridge or monoclinic plane, and m = 1 for the tectonic valley;

[0100] K i is the weighted average permeability of the i-th layer of the oil and gas display section in a single well, and the unit is md;

[0101] φ i is the weighted average porosity of the i-th layer of the oil and gas display section in a single well, dimensionless;

[0102] h i is the thickness of the i-th layer of the oil and gas display section in a single well, and the unit is m;

[0103] h is the total thickness of the oil and gas display section in a single well, and the unit is m;

[0104] μ is the dynamic viscosity of the oil and gas, and the unit is mPa·s;

[0105] a is the included angle between the buoyancy force direction of the oil and gas and the hydrodynamic direction, and the unit is °;

[0106] ρ w is the density of water in kg / m 3 ;

[0107] ρ o is the density of oil and gas, in kg / m 3 ;

[0108] g is the acceleration due to gravity, in m / s 2 ;

[0109] β is the inclination of the target layer, in degrees;

[0110] ΔP is the difference between the residual pressures of the two contour lines in the target layer pressure plane diagram, which is a positive value and the unit is Pa;

[0111] ΔL is the distance between two contour lines in the target layer pressure plane diagram, in meters.

[0112] This evaluation index is obtained based on Darcy's law, where To construct the ridge conductivity index, which characterizes the conductivity of the conductive ridge; It is the ratio of the product of equivalent permeability and equivalent porosity of the transport layer to fluid viscosity, representing the influence of geological factors and the properties of oil and gas on transport efficiency; is the combined force of the residual pressure gradient and buoyancy, which characterizes the influence of dynamic factors on the transport efficiency. The comprehensive evaluation index λ is the product of the three, which is equivalent to the improvement of Darcy's law and the introduction of the structural ridge or valley transport index. The transport efficiency of the migration channel is positively correlated with the evaluation results of both. Therefore, the larger the λ value, the higher the transport efficiency of the migration channel.

[0113] According to the comprehensive evaluation index λ (projecting the comprehensive evaluation index λ on the base map of the study area with the target layer accumulation / failed well mark or the target layer structural plane contour map and drawing the λ plane contour line), the oil and gas transport efficiency of the sandstone lateral migration channel is quantitatively characterized. The larger the λ value, the higher the transport efficiency; the λ high value area is found through the λ plane contour map, which is the dominant transport area of ​​the transport layer, that is, the favorable oil and gas migration area. Combined with the structural contour map of the top surface of the target layer in the study area and the distribution of traps, the favorable oil and gas convergence zone can be found. The migration of oil and gas on the plane is not a sheet-like diffusion migration, but a finger-like migration of the dominant channel. Therefore, the high value area of ​​the transport efficiency of the migration channel is often also the dominant oil and gas migration channel, which determines the main migration area of ​​oil and gas, that is, the favorable oil and gas accumulation zone, and the possibility of accumulation is much higher than that of the non-dominant migration channel. Finding the high value area of ​​the transport efficiency in the study area through the λ value of each single well and judging the favorable oil and gas accumulation and accumulation zone can be used as an important auxiliary and effective evaluation method for oil and gas exploration.

[0114] The present invention also provides a system for quantitatively characterizing the oil and gas conduction efficiency of the above-mentioned lateral migration channel of sandstone, including:

[0115] A ridge or valley conduction index and buoyancy data acquisition module, which is used to obtain the included angle θ between the contour lines on both sides of the structural ridge or valley and the dip angle β of the target layer at each well position according to the structural contour map of the top surface of the target layer, and construct the ridge or valley conduction index λ according to the included angle θ between the contour lines on both sides of the structural ridge or valley s , and obtain the buoyancy F1 received by the target layer at each well position according to the dip angle β of the target layer at each well position;

[0116] A remaining pressure difference gradient data acquisition module for each well position, which is used to obtain the remaining pressure difference gradient F2 at each well position according to the pressure plane distribution map of the target layer;

[0117] An included angle data acquisition module, which is used to overlay the structural contour map of the top surface of the target layer and the pressure plane distribution map to obtain the included angle a between the reverse extension line of the dip direction in the target layer at each well position and the direction of the remaining pressure difference gradient;

[0118] A comprehensive evaluation index construction module, which is used to obtain the weighted average permeability and weighted average porosity of the oil and gas display section of the target layer at each well position, and construct the comprehensive evaluation index λ at each well position in combination with the ridge or valley conduction index λ s at each well position, the buoyancy F1 received by the target layer at each well position, the remaining pressure difference gradient F2, and the included angle a;

[0119] An oil and gas conduction efficiency characterization module, which is used to quantitatively characterize the oil and gas conduction efficiency of the lateral migration channel of sandstone by using the comprehensive evaluation index λ at each well position. The higher the value of the comprehensive evaluation index λ, the higher the conduction efficiency.

[0120] Embodiment

[0121] Taking the Cretaceous Bashijiqike Formation sandstone conduction layer and the top unconformity in the southern slope zone of the Kuqa Depression in the Tarim Basin as an example for quantitative evaluation.

[0122] The southern slope zone of the Kuqa Depression is located on the Tabei Uplift in the Tarim Basin. It is N-E trending in a long strip shape with "narrow in the north-south direction and long in the east-west direction" in plan view. It is a typical distal oil and gas-bearing basin. The oil and gas come from the Triassic and Jurassic source rocks in the northern Baicheng Sag and Yangxia Sag. The oil and gas reservoirs in the western section of this area are mainly located in the Paleogene and Cretaceous. The thick Cretaceous Bashijiqike Formation sandstone layer distributed in large areas in the southern slope together with the bottom unconformity of the Paleogene at its top constitute the main conduction channels for lateral migration of oil and gas.

[0123] Figure 2It is a planar distribution map of the comprehensive evaluation index λ of the lateral conduction efficiency of the unconformity at the top of the Cretaceous Bashijiqik Formation and the underlying sandstone conduction layer in the study area, drawn based on the single-well evaluation results of 64 wells in the western section of the southern slope of Kuqa. Considering the actual hydrocarbon accumulation situation, it is considered that the area where λ > 0.3 is the effective hydrocarbon conduction area, and the effective conduction area is represented by the shaded part in the figure. Almost no hydrocarbon reservoirs have formed in the Cretaceous Bashijiqik Formation outside the effective hydrocarbon conduction area. In the effective migration area, except in the area near Well YM46 and Well YT12 where no effective traps were confirmed in the target layer during drilling, so the hydrocarbons passed through but did not form reservoirs, all the other drilled wells obtained industrial hydrocarbon reservoirs, and the hydrocarbon accumulation rate was close to 100% under the condition of effective traps. The oil source in the study area comes from the northern Baicheng Sag. According to the scope of the effective conduction area, it can be concluded that the injection point of the hydrocarbons entering the southern slope of Kuqa from the sandstone conduction layer of the Cretaceous Bashijiqik Formation should be located in the northern part of Well QL1 area, which is also consistent with the previous understanding results.

[0124] Based on the isoline map of the planar distribution of λ, combined with seismic prediction and the distribution of structural traps confirmed by drilling, the favorable hydrocarbon accumulation areas in the study area are determined, which are Well QL1 area in the northwest of the study area, Yudong (YD) 4 Well area in the central and southern part, Yangta (YT) 1 Well area in the middle, and Yangta 2-3 Well area in the northeast. Among them, Well YT1 area, Well YD4 area and their peripheries are the most favorable exploration zones. Figure 3 It is the quantitative evaluation result of the conduction efficiency of the favorable hydrocarbon accumulation well area (the evaluation result is the average value of the evaluation results of all single wells adjacent to the well area). The present invention provides a method for quantitatively characterizing the hydrocarbon conduction efficiency of the lateral migration channel of sandstone. According to the structural isoline map of the top surface of the target layer, the included angle between the isolines on both sides of the structural ridge or valley and the dip angle of the target layer at each well position are obtained. The conduction index of the structural ridge or valley is constructed according to the included angle of the isolines. The buoyancy received by the target layer at each well position is obtained according to the dip angle of the target layer. The residual pressure difference gradient at each well position is obtained according to the planar distribution map of the target layer pressure. The structural isoline map of the top surface of the target layer and the planar distribution map of the pressure are superimposed to obtain the included angle between the reverse extension line in the dip direction and the direction of the residual pressure difference gradient in the target layer at each well position. The weighted average permeability and porosity of the target layer at each well position, the conduction index of the structural ridge or valley at each well position, the buoyancy received by the target layer, the residual pressure difference gradient and the included angle are used to construct the comprehensive evaluation index of each well position. The hydrocarbon conduction efficiency of the lateral migration channel of sandstone is quantitatively characterized by using the comprehensive evaluation index of each well position. The present invention can intuitively and simply evaluate the conduction efficiency of the lateral conduction channel.

Claims

1. A quantitative characterization method for the oil and gas conduction efficiency of the lateral migration channels in sandstone, characterized in that, The specific steps are as follows: S1 According to the structural contour map of the top surface of the target layer, obtain the included angle θ between the contour lines on both sides of the structural ridge or valley at each well location and the dip angle β of the target layer at each well location. Construct the transport index λ of the structural ridge or valley according to the included angle θ between the contour lines on both sides of the structural ridge or valley. s , and obtain the buoyancy force F1 on the target layer at each well location according to the dip angle β of the target layer at each well location; S2 Obtain the remaining pressure difference gradient F2 at each well location according to the pressure plane distribution map of the target layer; S3 Superimpose the structure isopach map of the top surface of the target layer and the pressure plane distribution map to obtain the included angle a between the reverse extension line of the dip in the target layer and the direction of the remaining pressure difference gradient at each well location; S4 Obtain the weighted average permeability and weighted average porosity of the oil and gas display intervals of the target layers at each well location, and combine the ridge or valley transport index λ of each well location s 、 the buoyancy F1, the remaining pressure difference gradient F2, and the included angle a received by the target layer at each well location to construct the comprehensive evaluation index λ of each well location; S5 Use the comprehensive evaluation index λ at each well location to quantitatively characterize the oil and gas conduction efficiency of the sandstone lateral migration channel. The higher the value of the comprehensive evaluation index λ, the higher the conduction efficiency.

2. The quantitative characterization method for the oil and gas conduction efficiency of the lateral migration channel of sandstone according to claim 1, wherein In S1, the structure isopach map of the top surface of the target layer is obtained by correcting the elevation of the seismic reflection layer on the top surface of the target layer with the elevation of the top surface of the target layer of a single well; In S2, the pressure plane distribution map is obtained by interpolating the formation pressure data of the drill pipe test of the target layer of a single well between wells; In S4, the porosity is obtained by the theoretical formula of logging porosity or by fitting the logging curve and the measured porosity; The permeability is obtained by fitting the porosity, the shale content obtained from the natural gamma logging curve, and the measured permeability value of the core.

3. A quantitative characterization method for the oil and gas conduction efficiency of the lateral migration channels of sandstone, according to claim 1, characterized in that In S1, construct the ridge or valley conduction index λ s Obtained according to the following formula: In the formula, θ is the included angle between the isopachs on both sides of the structural ridge or valley, with the unit of °; m is a dimensionless number, m = -1 for the structural ridge or monoclinic plane, and m = 1 for the structural valley; In S1, if the well point is on the structural ridge, take the dip angle of the structural ridge as the dip angle value of this point; if the well point is inside the anticlinal trap, take the dip angle of the slope in the source direction of the trap as the dip angle value of this point.

4. A quantitative characterization method for the oil and gas transport efficiency of the lateral migration channels of sandstone, according to claim 1, wherein In S1, the buoyancy is obtained according to the following formula: F1 = (ρ w - ρ o ) * g * sinβ where: ρ w is the density of water, with the unit of kg / m 3 ; ρ o is the oil and gas density, with the unit of kg / m 3 ; g is the acceleration due to gravity, with the unit of m / s 2 ; β is the dip angle of the target layer, with the unit of °.

5. The quantitative characterization method for the oil and gas conduction efficiency of the sandstone lateral migration channel according to claim 1, wherein In S2, the remaining pressure difference gradient F2 is obtained according to the following formula: In the formula: ΔP is the remaining pressure difference between the two isopachs, with the unit of Pa; ΔL is the distance between the two isopachs, with the unit of m.

6. The quantitative characterization method for the oil and gas conduction efficiency of the sandstone lateral migration channel according to claim 1, wherein In S4, the calculation formula of the comprehensive evaluation index λ is as follows: F1 = (ρ w - ρ o ) * g * sinβ Where: θ is the included angle between the isoclines on both sides of the structural ridge or valley, with the unit of °; m is a dimensionless number, m = -1 for the structural ridge or monoclinic plane, and m = 1 for the structural valley; K i is the weighted average permeability of the i-th layer of the oil and gas showing interval in a single well, with the unit of md; φ i is the weighted average porosity of the i-th layer of the oil and gas showing interval in a single well, dimensionless; h i is the thickness of the i-th layer of the oil and gas showing interval in a single well, with the unit of m; h is the total thickness of the oil and gas showing interval in a single well, with the unit of m; μ is the dynamic viscosity of the oil-gas, with the unit of mPa·s; a is the angle between the direction of the oil-gas buoyancy and the direction of the hydrodynamic force, with the unit of °; ρ w is the density of water, with the unit of kg / m 3 ; ρ o is the oil and gas density, with the unit of kg / m 3 ; g is the acceleration of gravity, with the unit of m / s 2 ; β is the dip angle of the target layer, with the unit of °; ΔP is the difference in residual pressure between two isobars in the pressure plan of the target layer, taking a positive value, with the unit of Pa; ΔL is the distance between two isobars in the pressure plan of the target layer, with the unit of m.

7. A quantitative characterization method for the oil and gas transport efficiency of the lateral migration channels in sandstone, according to claim 6, wherein In S4, an automatic viscosity and density analyzer is used to test the physical properties of oil and gas to obtain the density and dynamic viscosity of oil and gas.

8. A quantitative characterization method for the oil and gas transport efficiency of the lateral migration channels of sandstone, according to claim 1, wherein Mark the comprehensive evaluation index λ at each well location on the structure isopach map of the top surface of the target layer or the base map of the study area work area with the marks of the successful / unsuccessful wells in the target layer to obtain the λ plane isopach map. The high-value area of the comprehensive evaluation index λ in the λ plane isopach map is the high-value area of the oil and gas conduction efficiency of the migration channel.

9. A method for determining favorable hydrocarbon accumulation zones, characterized in that, Use the quantitative characterization method for the oil and gas conduction efficiency of the sandstone lateral migration channel described in claim 8 to determine the high-value area of the oil and gas conduction efficiency of the migration channel, and combine the structure isopach map of the top surface of the target layer and the trap distribution in the study area to obtain the favorable oil and gas accumulation zones.

10. Operating a system for quantitatively characterizing the oil and gas transport efficiency of a lateral migration channel of sandstone according to any one of claims 1 to 8, characterized in that, Including: The ridge or valley conduction index and buoyancy data acquisition module is used to obtain the included angle θ between the contour lines on both sides of the ridge or valley of each well position and the dip angle β of the target layer of each well position according to the structural contour map of the top surface of the target layer, and construct the ridge or valley conduction index λ according to the included angle θ between the contour lines on both sides of the ridge or valley s , and obtain the buoyancy F1 received by the target layer of each well position according to the dip angle β of the target layer of each well position; A module for obtaining the remaining pressure difference gradient data at each well location, which is used to obtain the remaining pressure difference gradient F2 at each well location according to the pressure plane distribution map of the target layer; An included angle data acquisition module, which is used to superimpose the structure isopach map of the top surface of the target layer and the pressure plane distribution map to obtain the included angle a between the reverse extension line of the dip in the target layer and the direction of the remaining pressure difference gradient at each well location; The comprehensive evaluation index construction module is used to obtain the weighted average permeability and weighted average porosity of the oil and gas display intervals of the target layers at each well location, and combine the ridge or valley transportation index λ at each well location s 、the buoyancy F1, the residual pressure difference gradient F2, and the included angle a received by the target layer at each well location to construct the comprehensive evaluation index λ at each well location; An oil and gas conduction efficiency characterization module, which is used to use the comprehensive evaluation index λ at each well location to quantitatively characterize the oil and gas conduction efficiency of the sandstone lateral migration channel. The higher the value of the comprehensive evaluation index λ, the higher the conduction efficiency.

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