CN112282741A - Target reservoir well testing analysis method, computer storage medium and computer equipment - Google Patents
Target reservoir well testing analysis method, computer storage medium and computer equipment Download PDFInfo
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Abstract
The invention discloses a target reservoir well testing analysis method, a computer storage medium and computer equipment, wherein the method comprises the following steps: establishing a well testing analysis model according to geological characteristics of karst caves, cracks and bedrocks in a target reservoir; calculating a bottom hole pressure solution in a real space according to the well testing analysis model; wherein the bottom hole pressure is resolved as a bottom hole pressure versus time; drawing a model curve according to the bottom hole pressure solution, wherein the model curve comprises a pressure curve and a pressure derivative curve; and judging the liquid supply characteristics of the target reservoir according to the model curve. The method reflects the vertical fluid flow and deep stratum vertical liquid supply characteristics in the karst cave, provides a basis for determining accurate and reliable karst cave volume, high permeability zone flow capacity and geological reserve for the fracture-cavity type carbonate reservoir, provides basic information for dynamic evaluation of the reservoir, and plays an important role in guaranteeing high-efficiency development of the fracture-cavity type carbonate reservoir and improving economic benefit.
Description
Technical Field
The invention belongs to the technical field of oil exploration, and particularly relates to a fracture-cavity carbonate reservoir target reservoir well testing analysis method, a corresponding computer storage medium and corresponding computer equipment.
Background
Carbonate rock oil is hidden in the discovered oil reservoir in the world and occupies an important position, the discovery of the Tahe oil field in China is a new important breakthrough of the carbonate rock oil reservoir, and a new stage of the carbonate rock oil reservoir exploration and development in China is uncovered. The main body of the Tahe oil field is an Ordovician carbonate fracture-cave type oil reservoir, the main reservoir type is a fracture-cave type reservoir which is the result of multi-stage karst transformation, the reservoir space mainly comprises karst caves, holes, cracks and the like, the karst caves, the crack-hole type, the crack type and the cave type reservoir are formed by combining the reservoir spaces with obviously different characteristics, and the boundary forms of the reservoir in three-dimensional space distribution are extremely irregular; the storage space distribution is discontinuous, the porosity change is huge, the regularity is poor, and the heterogeneity is very serious. The storage space of the cave-type reservoir is large-scale cave and crack, the storage space of the cave (including big hole and big hole) is huge, and the crack plays a role in communicating the cave and improving seepage performance, so that a favorable reservoir type with huge storage space and excellent seepage storage capacity is formed. The well testing analysis can obtain key information such as karst cave volume, connectivity, reserves and the like of the fracture-cave reservoir, and has important significance for determining the reserves of the carbonate fracture-cave type oil reservoir and guiding the carbonate oil reservoir.
At present, fracture-cavity oil reservoirs mainly have two types of well testing analysis models: the first type is a continuous medium model, which mainly comprises a double medium model, a triple medium model or an equivalent triple medium model and a double composite model, such as the article 'triple medium oil reservoir well testing interpretation method research of variable shaft storage', 'carbonate karst cave type reservoir well testing interpretation new model', 'fracture cave type oil reservoir well testing model with a well drilled in a large-scale karst cave', and the like. The second type is a discrete medium model well testing model, such as the article "new technology application of Tahe carbonate reservoir well testing interpretation", "numerical well testing model of fracture-cave type reservoir with well drilled outside karst cave", and "well testing interpretation method for calculating karst cave volume" (application No. CN 201611139785.6).
However, the existing model and method are only suitable for carbonate reservoirs with karst caves and cracks radially distributed on the same plane, many carbonate reservoirs are bead-type karst caves, the karst caves are communicated by vertical cracks, and the flow is mainly in the vertical direction. Therefore, the existing well testing analysis method is poor in applicability to vertically flowing fracture-cavity reservoirs (such as bead string type karst caves).
Disclosure of Invention
The invention aims to solve the technical problem that the existing carbonate reservoir well testing model and method cannot be suitable for a carbonate reservoir with karst caves and cracks distributed vertically.
In order to solve the technical problem, the invention provides a target reservoir well testing analysis method, which comprises the following steps:
step 1, establishing a well testing analysis model according to geological characteristics of karst caves, cracks and bedrocks in a target reservoir;
and 4, judging the liquid supply characteristics of the target reservoir according to the model curve.
Preferably, in step 1, the well testing analysis model includes a cylindrical karst cave sub model, a first fracture zone sub model, a second fracture zone sub model and a shaft sub model, wherein:
the first fracture zone submodel is arranged above the upper boundary of the cylindrical karst cave submodel, is distributed vertically and is used for connecting the cylindrical karst cave submodel and the shaft submodel;
the second fracture region sub-model is arranged below the lower boundary of the cylindrical karst cave sub-model, is distributed vertically and is used for connecting the cylindrical karst cave sub-model with a target reservoir;
wherein the feed liquid of the well testing analysis model flows only in the first fracture zone sub model and the second fracture zone sub model.
Preferably, the flow of the feed liquid of the well test analysis model in only the first fracture zone sub model and the second fracture zone sub model is a one-dimensional vertical flow.
Preferably, the following steps are also included in step 2:
step 2.1, setting physical conditions of the well testing analysis model, and constructing a mathematical model of the well testing analysis according to the set physical conditions;
step 2.2, setting dimensionless parameters and dimensionless transforming the mathematical model;
step 2.3, performing Laplace transformation on the dimensionless mathematical model to obtain the pressure in the dimensionless karst cave in the Laplace space;
and 2.4, obtaining the dimensionless bottom hole pressure according to the relation between the bottom hole pressure and the dimensionless karst cave internal pressure, and calculating a bottom hole pressure solution in a real space according to the relation between the dimensionless bottom hole pressure and time.
Preferably, the dimensionless parameters in step 2.2 include: dimensionless pressure, dimensionless time, dimensionless distance, dimensionless wellbore coefficient, dimensionless karst cave storage coefficient, and dimensionless gravity coefficient.
Preferably, in step 2.4, a bottom hole pressure solution in real space is calculated by the Stehfest numerical inversion algorithm.
Preferably, in step 3, the model curve comprises curves of at least six flow regime segments, wherein the curve characteristics of any flow regime segment can be used for judging the liquid supply characteristics of the target reservoir.
Preferably, the six flow regime sections are specifically: the device comprises a shaft storage section, a skin effect section, a linear flow section, a transition flow section, a karst cave storage section and a boundary flow section.
Preferably, the liquid supply characteristic includes a liquid supply depth, the liquid supply depth being determined in accordance with a curvilinear characteristic of the boundary flow segment.
The present invention also provides a computer storage medium storing a computer program for implementing the target reservoir well testing analysis method as described above.
The invention also provides a computer device comprising a processor and a storage medium, wherein the processor is used for executing a computer program stored in the storage medium, and the computer program is used for realizing the target reservoir well testing analysis method.
Compared with the prior art, one or more embodiments in the above scheme can have the following advantages or beneficial effects:
by using the target reservoir well testing analysis method, a well testing analysis model for coupling vertical flow of the karst cave and the cracks is established from the geological characteristics of the karst cave, the cracks and the bedrock in the carbonate rock fracture-cave reservoir, the required dimensionless parameters are defined, and the solution of the model is obtained through Laplace transformation and Stehfest numerical inversion. The method can judge whether the karst cave exists or not through the transition flow section and the karst cave storage section, and provides a technical means for qualitatively judging the existence of the karst cave; the gravity influence in the vertical flow is considered by introducing the gravity coefficient in a dimensionless manner, so that the liquid supply characteristics of the reservoir stratum at the bottom depth can be more accurately reflected; namely, the method can reflect 6 complete flow states presented by the carbonate rock oil well which supplies liquid to the karst cave from the closed reservoir at a certain depth at the lower part of the karst cave, effectively reflects the whole flowing processes of shaft storage, liquid supply from the karst cave to the shaft, flowing in the karst cave, liquid supply from the bottom stratum to the karst cave and the like, has good adaptability to the carbonate rock oil well which supplies liquid to the karst cave from the closed reservoir at a certain depth at the bottom of the karst cave, and can be used for quantitatively determining key parameters such as the volume of the karst cave of the reservoir. Therefore, the method reflects the vertical fluid flow and the vertical liquid supply characteristics of the deep stratum in the karst cave, performs dynamic flow analysis on the fracture-cave carbonate reservoir with fractures and karst caves distributed vertically, provides a basis for determining the accurate and reliable karst cave volume, the high-permeability zone flow capacity and the geological reserve of the fracture-cave carbonate reservoir, provides basic information for dynamic evaluation of the reservoir, and has important effects on guaranteeing the high-efficiency development of the fracture-cave carbonate reservoir and improving the economic benefit.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 illustrates a flow chart of a target reservoir well testing analysis method of the present invention;
FIG. 2 illustrates a schematic diagram of a target reservoir structural model of the present invention;
FIG. 3 illustrates a reservoir feed status analysis diagram for an example well of the present invention;
Detailed Description
The following detailed description of the embodiments of the present invention will be provided with reference to the drawings and examples, so that how to apply the technical means to solve the technical problems and achieve the technical effects can be fully understood and implemented. It should be noted that, as long as there is no conflict, the embodiments and the features of the embodiments of the present invention may be combined with each other, and the technical solutions formed are within the scope of the present invention.
The well testing analysis can obtain key information such as karst cave volume, connectivity, reserves and the like of the fracture-cave reservoir, and has important significance for determining the reserves of the carbonate fracture-cave type oil reservoir and guiding the carbonate oil reservoir.
However, the existing model and analysis method have the following problems: the method is only suitable for the carbonate reservoir in which the karst caves and the fractures are radially distributed on the same plane; and many carbonate reservoirs are bead-string type karst caves which are communicated by vertical cracks, the flow is mainly vertical flow, and the existing well testing analysis method has poor applicability to the vertically flowing karst cave reservoirs.
Example one
In order to solve the technical problems in the prior art, the invention provides a target reservoir well testing analysis method, and fig. 1 shows a flow chart of the target reservoir well testing analysis method.
Referring to fig. 1, the target reservoir well testing analysis method of the embodiment includes the following steps:
step 1, establishing a well testing analysis model according to geological characteristics of karst caves, cracks and bedrocks in a target reservoir;
the well testing analysis model comprises a cylindrical karst cave sub-model, a first fracture region sub-model, a second fracture region sub-model and a shaft sub-model;
the first fracture zone submodel is arranged above the upper boundary of the cylindrical karst cave submodel, is distributed vertically and is used for connecting the cylindrical karst cave submodel and the shaft submodel;
the second fracture region sub-model is arranged below the lower boundary of the cylindrical karst cave sub-model, is distributed vertically and is used for connecting the cylindrical karst cave sub-model with a target reservoir;
wherein the feed liquid of the well testing analysis model flows only in the first fracture zone sub model and the second fracture zone sub model.
step 2.1, setting physical conditions of the well testing analysis model, and constructing a mathematical model of the well testing analysis according to the set physical conditions;
step 2.2, setting dimensionless parameters and dimensionless transforming the mathematical model;
step 2.3, performing Laplace transformation on the dimensionless mathematical model to obtain the pressure in the dimensionless karst cave in the Laplace space;
and 2.4, obtaining the dimensionless bottom hole pressure according to the relation between the bottom hole pressure and the dimensionless karst cave internal pressure, and calculating a bottom hole pressure solution in a real space through a Stehfest numerical inversion algorithm according to the relation between the dimensionless bottom hole pressure and time.
And 4, judging the liquid supply characteristics of the target reservoir according to the model curve. For example, the liquid supply characteristic includes a liquid supply depth.
Example two
In order to better explain the technical scheme of the present invention, this embodiment further explains the target reservoir well testing analysis method of the present invention:
the target reservoir well testing analysis method comprises the following steps:
step 1, establishing a well testing analysis model according to geological characteristics of karst caves, cracks and bedrocks in a target reservoir.
Referring to fig. 2, the well testing analysis model in the step 1 comprises a cylindrical karst cave sub model, a first fracture region sub model, a second fracture region sub model and a shaft sub model; wherein:
the first fracture zone submodel is arranged above the upper boundary of the cylindrical karst cave submodel, is distributed vertically and is used for connecting the cylindrical karst cave submodel and the shaft submodel;
the second fracture region sub-model is arranged below the lower boundary of the cylindrical karst cave sub-model, is distributed vertically and is used for connecting the cylindrical karst cave sub-model with a target reservoir;
and the liquid supply of the well testing analysis model flows vertically in one dimension only in the first fracture region sub model and the second fracture region sub model.
It is to be noted that, if there is a cavern in the reservoir, the cavern supplies liquid to the wellbore through a vertical fracture or a high permeability zone at the upper part of the cavern, and a closed reservoir at a certain depth at the bottom of the cavern also supplies liquid to the cavern through a vertical fracture or a high permeability zone. Starting from the geological characteristics of karst caves, cracks and bedrocks in a carbonate fracture-cave reservoir, a well testing analysis model for coupling vertical flow of the karst caves and the cracks is established, and the model considers the gravity influence, the flow of a high-permeability zone, the flow in the karst caves and the like.
The method comprises the specific steps of carrying out physical condition assumption on the well testing analysis model, constructing a mathematical model, defining required dimensionless parameters, carrying out dimensionless operation on the mathematical model, and obtaining a bottom hole pressure solution in a real space through Laplace transformation and a Stehfest numerical inversion algorithm. Further comprises the following steps:
step 2.1, setting physical conditions of the well testing analysis model, and constructing a mathematical model of the well testing analysis according to the set physical conditions;
specifically, firstly, a physical assumption is made on a well testing analysis model of a single karst cave vertical liquid supply type fracture-cavity carbonate reservoir from a bottom closed reservoir, and the physical assumption is as follows:
1. 1 karst cave is formed in the stratum, the karst caves are connected through cracks, and the properties of the karst caves are kept unchanged;
2. the solution cavity is a cylinder with radius rfThe upper boundary of the karst cave is h1The lower boundary is h2；
3. The pressure at the karst cave is equal everywhere;
4. the high permeability zone is represented by a crack, the crack is a crack with limited conductivity, the matrix permeability can be neglected compared with the crack permeability, namely the crack is the only flow channel between the karst cave and the shaft and between the stratum and the karst cave;
5. simplifying a fracture system between the karst caves into a cylindrical area, wherein the permeability in the area is equivalent to the permeability of the fracture in the area;
6. the oil reservoir temperature is unchanged, and the original formation pressure is equal everywhere;
7. the properties within each region remain unchanged;
8. the fluid in the formation is a single phase fluid;
9. the fluid and the rock are both micro-compressible, and the compression coefficients are both constants;
10. the lower boundary of the model is a vertical upper closed boundary;
11. well reserves, skin and gravitational effects are considered.
Based on the above assumptions, the flow in the model can be reduced to a one-dimensional vertical flow.
And then, constructing a well testing mathematical model of the bottom closed reservoir to a single karst cave vertical liquid supply type fracture-cave carbonate reservoir.
Under a one-dimensional rectangular coordinate system, considering the influence of gravity, and according to the mass conservation law, obtaining seepage control equations in a crack region 1 and a crack region 2 as follows:
in the formula:
p is pressure, Pa;
p1 is the pressure in fracture zone 1, Pa;
p2 is the pressure in fracture zone 1, Pa;
z is a vertical coordinate position, and the z axis is a one-dimensional coordinate axis which is established downwards by taking the center of a circle of the shaft as an origin;
rho is the fluid density, kg/m3；
g is gravity acceleration, m/s 2;
cfis the fluid compression coefficient, 1/Pa;
phi is porosity and is dimensionless;
u is the fluid viscosity, Pa · s;
Ctis the comprehensive compression coefficient, 1/Pa;
k is the permeability, md;
t is time, s.
The initial conditions were:
p(z，t＝0)＝pi (3)
in the formula: pi is the original formation pressure, Pa;
outer boundary conditions: a closed boundary is arranged at a certain depth of the bottom of the karst cave
In the formula: ze is the distance of the boundary, m.
Assuming that the pressure at the cavern is equal everywhere, there are:
p1(z＝h1，t)＝p2(z＝h2，t)＝pv (5)
in the formula:
h1 is the position of the upper boundary of the karst cave from the origin, m;
h2 is the position of the lower boundary of the karst cave from the origin;
pvis the pressure in the cavern, Pa;
let the storage coefficient of the cavern be CvAnd obtaining the flow relation at the upper and lower boundaries of the karst cave according to the mass conservation law:
in the formula:
rfis the radius of the karst cave, m;
Cvis the reservoir coefficient of the cavern, m3/Pa；
According to the conservation of mass and Darcy's law, the flow relation at the intersection of the fracture region 1 and the wellbore is obtained as follows:
in the formula:
q is daily yield, m3/s；
And B is the volume coefficient of the fluid.
Step 2.2, setting dimensionless parameters, and dimensionless transforming the mathematical model, specifically:
first, dimensionless parameter definition is performed as follows:
dimensionless pressure:
dimensionless time:
dimensionless distance:
dimensionless wellbore coefficient:
dimensionless cavern storage coefficient:
in the formula: c is a wellbore storage constant, m3/Pa。
Dimensionless gravity coefficient:
GD＝2ρgcf·rf
then, through the above-mentioned dimensionless variables that are defined, the mathematical model of the well test analysis is dimensionless, and the dimensionless seepage control equations in the first fracture area and the second fracture area are obtained in a one-dimensional rectangular coordinate system as follows:
in the formula
ω12＝(φct)1/(φct)2。
Dimensionless initial conditions:
pD(zD，0)＝0 (10)
dimensionless closed outer boundary condition
The dimensionless pressure relation at the karst cave is as follows:
p1D(zD＝zD1)＝p2D(zD＝zD2)＝pvD (12)
the dimensionless flow relation at the karst cave is as follows:
the dimensionless flow relation of the intersection of the first fracture zone and the shaft is as follows:
and 2.3, performing Laplace transformation on the dimensionless mathematical model to obtain the pressure in the dimensionless karst cave in the Laplace space.
Because the spatial term and the time term exist in the equations (8) - (9), the seepage control equation on the Laplace space is obtained by adopting Laplace transformation as follows:
closed outer boundary condition in Laplace
And (5) solving the formula (15), wherein the pressure in the dimensionless cavern in the Laplace space is obtained as follows:
in the formula:
obtaining dimensionless bottom hole pressure on a pull-type space by utilizing the relation between the bottom hole pressure and the karst cave pressure as follows:
and 2.4, obtaining the dimensionless bottom hole pressure according to the relation between the bottom hole pressure and the dimensionless karst cave internal pressure, and calculating a bottom hole pressure solution in a real space through a Stehfest numerical inversion algorithm according to the relation between the dimensionless bottom hole pressure and time.
Equation (18) is a solution of the established model in Laplace space, and a bottom hole pressure solution in real space, namely a relation between bottom hole pressure and time, can be obtained by a Stehfest numerical inversion algorithm.
And 3, drawing a model curve according to the bottom hole pressure solution, wherein the model curve comprises a pressure curve and a pressure derivative curve.
It should be noted that the bottom hole pressure solution drawing model curve includes a curve of six flow regime segments, where the six flow regime segments specifically are: the system comprises a shaft storage section, a skin effect section, a linear flow section, a transition flow section, a karst cave storage section and a boundary flow section, wherein the curve characteristic of any flow state section can be used for judging the liquid supply characteristic of a target reservoir.
And 4, judging the liquid supply characteristics of the target reservoir according to the model curve.
It should be noted that the model curve effectively reflects the flow characteristics of shaft storage, solution cavity liquid supply to the shaft, solution cavity flow, bottom stratum liquid supply to the solution cavity and the like, so that the characteristic parameters of the solution cavity size, the high permeability zone flow guiding capacity and the like are obtained through the flow dynamic analysis of the bottom liquid supply solution cavity type carbonate rock, the pressure recovery test actual measurement data and the model data fitting, the reserve scale is further judged, and the model curve can also be used for the prediction analysis of the yield characteristics and the pressure characteristics of the carbonate oil-gas well in the production process.
The embodiment reflects the vertical fluid flow and the vertical liquid supply characteristics of the deep stratum in the karst cave, performs dynamic flow analysis on the fracture-cave carbonate reservoir with the fractures and the karst cave distributed vertically, provides a basis for determining the accurate and reliable karst cave volume, the high-permeability zone flow capacity and the geological reserve of the fracture-cave carbonate reservoir, provides basic information for dynamic evaluation of the reservoir, and plays an important role in guaranteeing the high-efficiency development of the fracture-cave carbonate reservoir and improving the economic benefit.
EXAMPLE III
Step 4 in example two will now be described in further detail by way of example.
Referring to fig. 3, taking a well in a carbonate reservoir as an example, a cavern is located 50 meters from the bottom of the well, and supplies liquid to the wellbore through a hypertonic strip, while a reservoir 500 meters below the bottom of the cavern also supplies liquid to the cavern through a hypertonic strip, and the permeability of the hypertonic strip is 1000 md. The well pressure recovery is simulated to obtain a double logarithmic curve of the differential pressure and the differential pressure derivative in the pressure recovery process, namely, figure 3. As can be seen from figure 3, the carbonate rock oil well with the bottom reservoir supplying liquid to the karst cave presents 6 flow states which are respectively a shaft storage section, a skin section, a linear flow section, a transition flow section, a karst cave storage section and a boundary flow section.
It should be noted that:
the flow state 1 is a shaft storage section and is characterized in that the slopes of a differential pressure curve and a differential pressure derivative curve are both 1;
the flow state 2 is a skin section and is characterized in that a derivative curve has a peak, and the larger the skin is, the larger the peak value is;
flow regime 3 is a linear flow, representing flow in a hypertonic strip, characterized by a differential pressure derivative curve slope of 1/2;
flow regime 4 is a transition flow, representing a transition from a hypertonic strip to a cavern flow, with a sudden change in flow path resulting in a dip in the derivative curve;
the flow state 5 is a karst cave storage section and represents the flow in the karst cave 1, and the slope of a differential pressure derivative curve is 1;
the flow state 6 is a boundary flow section, the slope of a differential pressure curve and the slope of a differential pressure derivative curve both tend to 1, and the characteristic that the bottom closed reservoir continuously supplies liquid to the karst cave through a high permeability strip is reflected.
In which, the flow states 4 and 5 are present due to the existence of the karst cave, so we can judge whether the karst cave exists by the presence of the flow states 4 and 5.
The above embodiment achieves the following effects: (1) whether the karst cave exists or not can be judged through the transition flow section and the karst cave storage section, and a technical means is provided for qualitatively judging the existence of the karst cave; (2) by introducing the gravity coefficient in a dimensionless manner, the gravity influence in the vertical flow is considered, and the liquid supply characteristics of a closed reservoir at a certain depth at the bottom can be more accurately reflected; (3) the depth of the bottom liquid supply can be calculated through the boundary characteristics; (4) the method can reflect 6 complete flow states presented by the carbonate oil well supplying liquid to the karst cave from a reservoir stratum in the deep bottom, effectively reflect the whole flowing processes of shaft storage, karst cave liquid supply to the shaft, flow in the karst cave, bottom stratum liquid supply to the karst cave and the like, obtain characteristic parameters such as the size of the karst cave, the high permeability zone flow conductivity and the like by fitting pressure recovery test measured data and model data, further judge the reserve scale, and can also be used for predicting and analyzing the yield characteristics and the pressure characteristics of the carbonate oil gas well in the production process.
Through the embodiments, the method provided by the invention can be fully demonstrated to provide a basis for determining accurate and reliable karst cave volume, high permeability zone flow capacity and geological reserve for the fracture-cavity type carbonate reservoir, provide basic information for dynamic evaluation of the reservoir, well solve the problem that the existing well testing analysis method is poor in applicability to the fracture-cavity reservoir with vertical flow, and play an important role in guaranteeing efficient development of the fracture-cavity type carbonate reservoir and improving economic benefit.
Although the embodiments of the present invention have been described above, the above description is only for the convenience of understanding the present invention, and is not intended to limit the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A target reservoir well testing analysis method is characterized by comprising the following steps: the method comprises the following steps:
step 1, establishing a well testing analysis model according to geological characteristics of karst caves, cracks and bedrocks in a target reservoir;
step 2, calculating a bottom hole pressure solution in a real space according to the well testing analysis model; wherein the bottom hole pressure is resolved as a bottom hole pressure versus time;
step 3, drawing a model curve according to the bottom hole pressure solution, wherein the model curve comprises a pressure curve and a pressure derivative curve;
and 4, judging the liquid supply characteristics of the target reservoir according to the model curve.
2. The method of claim 1, wherein: in the step 1, the well testing analysis model comprises a cylindrical karst cave sub-model, a first fracture region sub-model, a second fracture region sub-model and a shaft sub-model; wherein:
the first fracture zone submodel is arranged above the upper boundary of the cylindrical karst cave submodel, is distributed vertically and is used for connecting the cylindrical karst cave submodel and the shaft submodel;
the second fracture region sub-model is arranged below the lower boundary of the cylindrical karst cave sub-model, is distributed vertically and is used for connecting the cylindrical karst cave sub-model with a target reservoir;
wherein the feed liquid of the well testing analysis model flows only in the first fracture zone sub model and the second fracture zone sub model.
3. The method of claim 2, wherein: and the liquid supply of the well testing analysis model flows in the first fracture region sub model and the second fracture region sub model only in a one-dimensional vertical direction.
4. The method of claim 1, wherein: the step 2 comprises the following steps:
step 2.1, setting physical conditions of the well testing analysis model, and constructing a mathematical model of the well testing analysis according to the set physical conditions;
step 2.2, setting dimensionless parameters and dimensionless transforming the mathematical model;
step 2.3, performing Laplace transformation on the dimensionless mathematical model to obtain the pressure in the dimensionless karst cave in the Laplace space;
and 2.4, obtaining the dimensionless bottom hole pressure according to the relation between the bottom hole pressure and the dimensionless karst cave internal pressure, and calculating a bottom hole pressure solution in a real space through a Stehfest numerical inversion algorithm according to the relation between the dimensionless bottom hole pressure and time.
5. The method of claim 4, wherein: the dimensionless parameters in step 2.2 include: dimensionless pressure, dimensionless time, dimensionless distance, dimensionless wellbore coefficient, dimensionless karst cave storage coefficient, and dimensionless gravity coefficient.
6. The method of claim 1, wherein: in step 3, the model curve comprises curves of at least six flow regime sections, wherein the curve characteristics of any flow regime section can be used for judging the liquid supply characteristics of the target reservoir.
7. The method of claim 6, wherein: the six flow state sections are specifically: the device comprises a shaft storage section, a skin effect section, a linear flow section, a transition flow section, a karst cave storage section and a boundary flow section.
8. The method of claim 7, wherein: the liquid supply characteristic includes a liquid supply depth determined from a curvilinear characteristic of the boundary flow segment.
9. A computer storage medium, characterized in that: which stores a computer program for implementing the target reservoir well testing analysis method according to any of claims 1-9.
10. A computer device, characterized by: comprising a processor and a storage medium, the processor being adapted to execute a computer program stored in the storage medium, the computer program being adapted to implement the target reservoir well testing analysis method according to any of claims 1-9.
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