CN116108572A - Shale gas condensate well volume fracturing outer zone productivity contribution analysis method - Google Patents
Shale gas condensate well volume fracturing outer zone productivity contribution analysis method Download PDFInfo
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Abstract
The invention relates to a shale gas condensate well volumetric fracturing outer zone productivity contribution analysis method, which comprises the following steps: based on complex fracture network characteristics and oil-gas two-phase flow characteristics in the shale gas condensate well fracturing development process, establishing a mathematical physical model based on a tri-linear flow theory, wherein the model is used for equivalently treating the complex fracture network of the shale gas condensate well into a fracturing modification body, and the fracturing modification body comprises an artificial main fracture, a fracturing modification inner area and a fracturing modification outer area; performing history fitting on the produced shale gas condensate well dynamics based on a mathematical physical model of a tri-linear flow theory to obtain typical shale and fracturing fracture parameters; based on typical shale and fracturing fracture parameters, different fracturing transformation outer zone boundary lengths are analyzed, and under different fracturing transformation outer zone permeability conditions, the contribution degree of the fracturing transformation outer zone to productivity is given out, so that reasonable well spacing considering the fracturing transformation outer zone contribution degree is provided.
Description
Technical Field
The invention relates to a shale gas condensate well volumetric fracturing outer zone productivity contribution analysis method, and belongs to the technical field of oil and gas mineral exploration and development.
Background
Shale oil and gas fields are important mineral resources for oil and gas development, but because shale is extremely dense, the matrix permeability is tens to hundreds of nanodarcies, so that the matrix outside the fracturing modification zone is generally considered to contribute little to the yield and can be ignored. Therefore, when the reasonable well spacing of the shale oil gas well is determined, theoretical calculation and micro-seismic monitoring of the fracturing cracks are often used as the main factors, and the cracks are simulated according to the physical properties, brittleness, ground stress and the like of the shale and the construction designs such as displacement and the like, so that the achievable half length of the fracturing cracks is determined; the oil reservoir engineering profession analyzes the influences of parameters such as fracture half-length, flow conductivity, matrix permeability and the like on yield and economy according to an oil reservoir engineering method or a numerical simulation method, so that a theoretical optimal well distance is optimized; the theoretical optimization design is also combined with on-site crack monitoring, and according to the fracture morphology and distribution range of microseism monitoring, the half-length of the fracture is taken as a reasonable well distance, but in practice, the well distance of the shale gas horizontal well in North America is always in continuous optimization process according to factors such as geology, fluid, process and the like.
According to actual production data of the North American hawk beach condensate gas well, under the condition that the fracturing parameters are basically consistent in the same area, the yield is decreased progressively with the increase of the well spacing, as shown in figure 1, the fact that the area outside the fracturing modification area (SRV) can supply gas to the modification area is shown, so that the yield of the gas well is increased, and the oil gas decreasing rate is reduced. How to evaluate the impact of areas outside the fracture reformation zone (SRV) on hydrocarbon production is an urgent issue to be addressed.
Disclosure of Invention
Aiming at the technical problems, the invention provides a volumetric fracturing external zone productivity contribution analysis method of a shale gas condensate well, which establishes a mathematical physical model based on a tri-linear flow theory aiming at complex fracture network characteristics and oil-gas two-phase flow characteristics in the shale gas condensate well fracturing development process, obtains typical shale and fracturing fracture parameters on the basis of history fitting of produced shale gas condensate well dynamics, and develops fracturing transformation external zone productivity contribution analysis on the basis of the typical shale and fracturing fracture parameters.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
a shale gas condensate well volumetric fracturing outer zone productivity contribution analysis method comprises the following steps:
based on complex fracture network characteristics and oil-gas two-phase flow characteristics in the shale gas condensate well fracturing development process, establishing a mathematical physical model based on a tri-linear flow theory, wherein the model is used for equivalently treating the complex fracture network of the shale gas condensate well into a fracturing modification body, and the fracturing modification body comprises an artificial main fracture, a fracturing modification inner area and a fracturing modification outer area;
performing history fitting on the produced shale gas condensate well dynamics based on a mathematical physical model of a tri-linear flow theory to obtain typical shale and fracturing fracture parameters;
based on typical shale and fracturing fracture parameters, different fracturing transformation outer zone boundary lengths are analyzed, and under different fracturing transformation outer zone permeability conditions, the contribution degree of the fracturing transformation outer zone to productivity is given out, so that reasonable well spacing considering the fracturing transformation outer zone contribution degree is provided.
In the shale gas condensate well volumetric fracturing outer zone capacity contribution analysis method, preferably, the establishment of the mathematical physical model of the three-linear flow theory is based on the following assumption:
the shale reservoir is of horizontal equal thickness, the horizontal well is positioned in the center of the reservoir, and the crack penetrates through the whole reservoir;
considering the compressibility of oil and gas, neglecting the compressibility of rock;
the adsorption and desorption of the gas are subject to a Langmuir single-layer adsorption model, and the adsorption mechanism of the condensate is not clear and is not considered independently;
the fluid consists of two components, namely oil and gas, the gas component only exists in the gas phase, and the oil component can exist in the oil phase and the gas phase at the same time.
According to the shale gas condensate well volumetric fracturing outer zone capacity contribution analysis method, preferably, the equation of the fracturing reconstruction outer zone is as follows:
the fracturing transformation outer region is a matrix region, and adsorption and desorption of gas are described by using Langmuir theory.
Wherein V is L Is Langerhans' volume; p (P) L Is Langerhans pressure; p is the pressure; v is the gas adsorption amount in the rock per unit volume;
the differential equation of the seepage of the oil and gas in the fracturing reforming outer zone is as follows:
gas composition:
oil component:
wherein k is Arg Is the relative permeability of the gas phase in the outer zone; k (k) Ar o is the relative permeability of the oil phase in the outer zone; k (k) A Permeability for the outer zone matrix; phi (phi) A Porosity for the outer region matrix; s is S Ag Saturation of the outer zone with gas; s is S Ao Oil saturation for the outer zone; mu (mu) g Is the viscosity of the gas; mu (mu) o Is the viscosity of crude oil; b (B) g Is the gas volume coefficient; b (B) o Is the volume coefficient of crude oil; p is p A Is the outer zone pressure; t is the production time; r is R v The content of the dissolved condensate oil in the gas phase; v (V) L Is Langerhans' volume;p L is Langerhans pressure; y is the coordinate direction.
In the analysis method for the capacity contribution of the volumetric fracturing outer zone of the shale gas condensate well, preferably, the fracturing reconstruction inner zone is a dual medium, the medium is regarded as a flat plate by using an unsteady mass transfer model, and the influence on the adsorption gas content refers to the fracturing reconstruction outer zone, so that the flow equation in the matrix is as follows:
gas composition:
oil component:
wherein k is mrg Is the relative permeability of the gas phase in the inner zone matrix; k (k) mro Relative permeability of oil phase in the inner zone matrix; k (k) m Permeability for the inner zone matrix; phi (phi) m Porosity for the inner zone matrix; s is S mg Saturation of the gas in the inner zone matrix; s is S mo Saturation of oil in the inner zone matrix; p is p m Is the internal zone matrix pressure; z is the coordinate direction.
In the analysis method for volumetric fracturing outer zone capacity contribution of shale gas condensate well, preferably, because of the existence of matrix in fracturing transformation inner zone cracks and the supply of the fracturing transformation outer zone, a flow equation in the matrix is as follows:
gas composition:
oil component:
wherein k is frg The relative permeability in the secondary fracture of the inner zone; k (k) fro The relative permeability of the oil phase in the secondary cracks of the inner zone; k (k) f Is insideZone secondary fracture permeability; phi (phi) f Secondary fracture porosity for the inner zone; s is S fg The saturation of gas in the secondary cracks of the inner zone; s is S fo The saturation of oil in the secondary crack of the inner zone; p is p f The secondary fracture pressure in the inner zone; q gmf The mass of gas flowing into the unit volume of the secondary fracture from the inner zone matrix system in unit time; q gAf The mass of the gas flowing into the unit volume of the secondary crack for the matrix system in the inner area and the outer area in unit time; x is the coordinate direction.
In the analysis method for volumetric fracturing outer zone capacity contribution of shale gas condensate well, preferably, considering fluid exchange from fracturing transformation inner zone cracks to artificial cracks, a seepage equation in the artificial cracks is as follows:
gas composition:
oil component:
wherein k is Frg Relative permeability in the artificial fracture; k (k) Fr o is the relative permeability of the oil phase in the artificial fracture; k (k) F Is the permeability of the artificial crack; phi (phi) F Is the porosity of the artificial crack; s is S Fg The gas saturation in the artificial crack; s is S Fo The saturation degree of oil in the artificial crack; p is p F Is the pressure of the artificial crack; q gfF The mass of gas flowing into the artificial crack in unit volume from the secondary crack in unit time; q ofF The mass of crude oil flowing into the artificial fracture in unit volume from the secondary fracture in unit time; x is the coordinate direction.
The volumetric fracturing outer zone capacity contribution analysis method of the shale gas condensate well preferably comprises the following steps of: the crack is half-long, the secondary crack permeability, the inner/outer region matrix permeability, the artificial joint flow conductivity and the matrix block width of the fracturing transformation inner region.
Due to the adoption of the technical scheme, the invention has the following advantages:
1. aiming at complex fracture network characteristics and oil-gas two-phase flow characteristics in the shale gas condensate well fracturing development process, a mathematical physical model based on a tri-linear flow theory is established, typical shale and fracturing fracture parameters are obtained on the basis of history fitting on the produced shale gas condensate well dynamics, and on the basis, fracturing transformation out-zone productivity contribution analysis is carried out.
2. The research result of the analysis method shows that the fracturing transformation outer zone has a certain contribution to the capacity of the shale gas condensate well, and the capacity contribution is increased along with the increase of the matrix permeability. In the first 5 years of production, the outer region range within 40m has a certain contribution to the productivity, and the main contribution is within 20 m; for 30 years of production, the contribution of the fracturing reconstruction outer region to the productivity is concentrated within 60 meters. Based on the analysis of the contribution of the yield of the outer zone in the previous 5 years and the previous 30 years, the range of the outer zone can be considered properly in the optimization of the well spacing in the eagle beach shale condensate gas zone, but the yield is not excessively large and is controlled to be within 20m as much as possible. The analysis method can provide reference for the development of domestic shale gas condensate.
Drawings
FIG. 1 is a graph showing the comparison of oil production from condensate wells with well spacing of 500 m and 150 m, respectively, according to the present invention;
FIG. 2 is a graph of a three-linear flow mathematical physical model of a shale fracking horizontal well, wherein Xe is the outer boundary range, y, provided in this embodiment of the invention e For the outer boundary range, y F The artificial crack is half-long;
FIG. 3 is a bottom hole flow chart of the shale S1 well provided by the embodiment of the invention;
FIG. 4 is a graph showing the initial gas-oil ratio of the shale S1 well provided by this embodiment of the invention;
FIG. 5 is a graph of a fit and prediction of shale S1 well oil production provided by this embodiment of the invention;
FIG. 6 is a graph of a fit and prediction of shale S1 well gas production provided by this embodiment of the invention;
FIG. 7 is a graph showing the gas production/cumulative gas production over time for different outer zone lengths provided by this embodiment of the present invention;
FIG. 8 is a graph showing the oil production/cumulative oil production over time for different outer zone lengths provided by this embodiment of the present invention;
FIG. 9 is a graph showing the relationship between the gas production contribution rate and the length of the outer zone for the first 5 years at different permeability of the outer zone according to the embodiment of the present invention;
FIG. 10 is a graph showing the relationship between the oil production contribution rate and the length of the outer zone at different permeability levels for the outer zone according to the embodiment of the present invention;
FIG. 11 is a graph showing the relationship between the gas production contribution rate and the length of the outer zone for the first 30 years at different permeability of the outer zone according to the embodiment of the present invention;
FIG. 12 is a graph showing the relationship between the contribution rate of oil production and the length of the outer zone for the first 30 years at different permeability of the outer zone according to the embodiment of the present invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the present invention will be clearly and completely described below, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are intended to be within the scope of the present disclosure.
Aiming at the problem that matrixes outside a fracturing transformation area contribute to yield in the existing shale oil and gas field development process, the invention provides a method for analyzing volumetric fracturing external capacity contribution of a shale gas condensate well.
The shale oil-gas field is located in a bay basin in the south of Texas in the United states, the shale oil-gas main force production layer is an eagle beach group, and the longitudinal eagle beach group is divided into an upper section and a lower section. In the shale oil gasIn the early stage of field development, the dominant force producing layer is the lower section of the hawk-beach group, and in recent years, along with the progress of development technologies such as fracturing, local areas are also trying to develop the upper section of the hawk-beach group, and a certain effect is achieved. The eagle beach group deposition environment was controlled by a multi-stage construction event, developed in a mid-late chalky paleo-marine land frame deposition environment of about 85Ma from now, directly overlying the late tria and dwarf sedimentary carbonate formations. The lower section of the hawk beach group has good sealing conditions, and the overlying stratum is mudstone at the upper section of the hawk beach group, and the part is the Ostine chalk limestone; the underlying formation is brada and locally deli about mar. The buried depth of the hawk beach group on land is about 1500-4900 m, and the average thickness is 76m. Black shale/mudstone is developed at the lower section of the hawk beach group, the average content of carbonate minerals is 58 percent, the average content of clay minerals is 16.5 percent, the average value is 4.23 percent, and the main development II is that 1 Kerogen type. The lower Ro value of the hawk beach group gradually increases from North west to south east. According to the collected 2-thousand-mouth in-production-well production data, the eagle beach shale area is divided into 5 oil-gas producing areas of black oil, volatile oil, condensate gas, moisture and dry gas according to an initial gas-oil ratio. The oil gas produced in the area is mainly controlled by the maturity of the organic matters. The invention takes condensate gas zone as a research object.
The invention relates to a shale gas condensate well volumetric fracturing outer zone capacity contribution analysis method, which comprises the following specific analysis processes:
1. mathematical physical model based on tri-linear flow theory
According to microseism data in the process of hydraulic fracturing of a great number of hawk beaches, a shale condensate gas well forms a very complex fracture network in a shale layer after hydraulic fracturing transformation. According to the studies of the former Wu Yonghui, etc., a complex fracture network can be equivalently processed into a fracture modifier (SRV) consisting of an artificial main fracture, a fracture modifier inner zone, and a fracture modifier outer zone, as shown in fig. 2. The fracturing transformation inner area mainly considers the fracturing transformation to form a complex fracture network system, and is processed into a dual medium, and the existing Kazemi and other unsteady state channeling models can be adopted due to the low inherent permeability of the matrix; the fracturing reconstruction outer region is not subjected to fracturing reconstruction, so that the fracturing reconstruction outer region is processed into a single-hole medium. In each zone, the flow of fluid is treated as a linear flow, i.e., the outer zone fluid flows linearly into the inner zone fracture matrix, the fluid in the inner zone matrix flows linearly into the inner zone fracture medium, and then flows linearly from the inner zone fracture into the artificial fracture (as shown in fig. 2).
Based on complex fracture network characteristics and oil-gas two-phase flow characteristics in the shale gas condensate well fracturing development process, a mathematical physical model based on a tri-linear flow theory is established, and the establishment of the model is based on the following assumption:
(1) The shale reservoir is of horizontal equal thickness, the horizontal well is positioned in the center of the reservoir, and the crack penetrates through the whole reservoir;
(2) Considering the compressibility of oil gas, neglecting the compressibility of rock;
(3) The adsorption and desorption of the gas are subject to a Langmuir single-layer adsorption model, and the adsorption mechanism of the condensate is not clear and is not considered independently;
(4) The fluid consists of two components of oil and gas, the gas component exists in the gas phase only, and the oil component can exist in the two phases of oil and gas simultaneously.
1.1 fracturing modification the equation for the outer zone is:
the fracturing transformation outer region is a matrix region, and adsorption and desorption of gas are described by using Langmuir theory.
Wherein V is L Is Langerhans' volume; p (P) L Is Langerhans pressure; p is the pressure; v is the gas adsorption amount in the rock per unit volume;
the differential equation of the seepage of the oil and gas in the fracturing reforming outer zone is as follows:
gas composition:
oil component:
initial conditions:
p A | t＝0 ＝p i (4)
outer boundary conditions:
inner boundary conditions:
wherein p is i Is the original formation pressure.
1.2 fracturing modification of the inner zone to be a dual medium, using an unsteady mass transfer model (Kazemi model), regarding the medium as a flat plate, referring to the fracturing modification outer zone for the influence of the adsorbed gas content, therefore, the flow equation in the matrix is:
gas composition:
oil component:
initial conditions:
p m | t＝0 ＝p i (9)
outer boundary conditions:
inner boundary conditions:
in the method, in the process of the invention,h m is the matrix block width.
1.3 because of the presence of matrix in the fracture modification inner zone and the provision of the fracture modification outer zone, the flow equation in the matrix is:
gas composition:
oil component:
initial conditions:
p f | t＝0 ＝p i (14)
outer boundary conditions:
inner boundary conditions:
1.4 considering the fluid exchange of a fracture in the fracture modification zone to an artificial fracture (indicated by the subscript F), the percolation equation in the artificial fracture is:
gas composition:
oil component:
initial conditions:
p F | t＝0 ＝p i (19)
outer boundary conditions:
inner boundary conditions:
p F | y＝0 ＝p wf (21)
wherein p is wf Is the bottom hole flow pressure.
2. Inversion of typical shale gas condensate well fracture and reservoir parameters
And (3) taking the shale S1 well of the condensate gas well as a research object, and fitting the yield of the condensate gas well by using a dynamic history fitting method of production data. The pressure is unstable in the whole production stage and is influenced by a switching well, the pressure change is large, and the overall trend is that the bottom hole pressure is gradually reduced as seen from a change chart (figure 3) of the bottom hole pressure. Fig. 4 shows the initial gas-oil ratio of the well, which can be seen to be relatively stable over the last two years. Fig. 5 and 6 show the oil and gas production fitting effect, and overall the fitting effect is better, but the oil production fitting is worse before and after well shut-in. The fitting crack parameters are shown in table 1, the fitting parameter values are within the error allowable range, and the fitting effect is good. Table 1 is the inverted reservoir and fracture parameters.
Table 1 reservoir and fracture parameter inversion
3. Fracturing transformation outer zone capacity contribution and reasonable well spacing analysis
Based on typical shale and fracturing fracture parameters given in Table 2, the contribution degree of the outer zone to the productivity under different outer zone boundary lengths and different outer zone permeability conditions is analyzed, so that reasonable well spacing suggestions considering the contribution degree of the outer zone can be given.
Table 2 formation parameters table for condensate gas well
| Parameters (parameters) | Value taking | Parameters (parameters) | Value taking |
| Original formation pressure, MPa | 38 | Formation thickness, |
20 |
| Original formation temperature, K | 387 | Horizontal segment length, m | 2000 |
| Bottom hole pressure, |
6 | Inner/outer zone matrix porosity | 0.10 |
| Number of fracturing |
20 | Porosity of secondary cracks | 1.0 |
| Half length of split seam, |
100 | Porosity of artificial cracks | 0.5 |
| Flow conductivity of artificial joint, D.cm | 5 | Inner zone matrix permeability, |
5e-4 |
| Secondary fracture permeability, |
2 | Original saturation of gas | 1.0 |
3.1 law of influence of the size of the outer region on productivity
The fracturing greatly increases the productivity of shale oil and gas wells, and meanwhile, the outer zone also has a certain contribution to the productivity, so that the contribution condition of the outer zone to the productivity under the conditions of different outer zone sizes and outer zone permeability is required to be clarified. Therefore, the permeability of the inner region and the outer region is set to be 5e-4mD, the length of the manual seam is 100m, the sizes of the outer regions are respectively 0m, 20m, 40m, 60m, 80m and 100m, and the contribution condition of the sizes of the different outer regions to the productivity is analyzed. FIG. 7 shows the gas production/cumulative gas production over time for different outer zone lengths, showing that the outer zone length has less effect on instantaneous gas production during the initial stage of production and the greater the outer zone length, the greater the cumulative gas production during the late stage of production. FIG. 8 shows the oil production/cumulative oil production versus time for different outer zone lengths, showing that the outer zone length has less effect on instantaneous oil production during the initial stage of production and the greater the outer zone length, the greater the cumulative oil production during the post-production period. Combining FIGS. 7 and 8, it is believed that the capacity forecast results will be lower without considering the contribution of the outer zone to capacity; the outer zone has smaller contribution to the energy production of the previous 5 years, has a certain contribution to the later-stage yield, and increases the yield, but gradually decreases the increase.
3.2 contribution of the outer region to yield plate
To more intuitively understand the contribution of the outer zone to the capacity in the early stage of production (the first 5 years), a plate is made of typical outer zone matrix permeability, outer zone size contribution to capacity. Thus, the matrix permeability of the inner zone is set to be 5e-4mD, and the outer zone permeability is respectively: 5e-4mD, 2.5e-4mD, 1e-4mD, 5e-5mD, and the outer areas are 0m, 20m, 40m, 60m, 80m, and 100m respectively.
FIG. 9 is a graph showing the relationship between the gas production contribution rate and the length of the outer zone for the first 5 years at different permeability of the outer zone. When the length of the outer zone is less than 40m, the gas production contribution rate rapidly rises along with the increase of the length of the outer zone; when the length of the outer zone is greater than 40m, the gas production contribution rate does not substantially rise as the length of the outer zone increases. The greater the permeability of the outer zone, the more rapidly the gas production contribution rises, and the higher the gas production contribution at the same length of the outer zone. FIG. 10 is a graph showing the oil production contribution rate versus the length of the outer zone at different permeability rates of the outer zone. When the length of the outer zone is less than 40m, the oil production contribution rate rapidly rises along with the increase of the length of the outer zone; when the length of the outer zone is greater than 40m, the oil production contribution rate does not rise any more as the length of the outer zone increases. The greater the outer zone permeability, the more rapidly the oil production contribution rises, and the higher the oil production contribution at the same outer zone length. By combining fig. 9 and 10, in the first 5 years of production, the outer region size is within 40m, which contributes to the productivity to a certain extent, and mainly within 20m, while the part larger than 40m contributes little to the productivity; the greater the outer zone permeability, the greater the contribution to capacity.
To more intuitively understand the contribution of the outer zone to the 30-year yield, a plate with different outer zone matrix permeabilities and outer zone sizes contributing to the productivity was made. Thus, the following is set: the permeability of the matrix in the inner area is 5e-4, and the permeability of the matrix in the outer area is respectively: 5e-4mD, 2.5e-4mD, 1e-4mD, 5e-5mD, and the outer areas are 0m, 20m, 40m, 60m, 80m, and 100m respectively.
FIG. 11 is a graph showing the relationship between the gas production contribution rate and the length of the outer zone for the first 30 years at different permeability of the outer zone. When the outer zone length is less than 20m, the gas production contribution rate of different outer zone permeabilities increases with the outer zone length at the same rate; when the length of the outer zone is more than 20m, the higher the permeability of the outer zone is, the higher the gas production contribution rate is; the greater the outer zone length, the more gentle the gas production contribution rate curve increases with the outer zone length. FIG. 12 is a graph showing the relationship between the contribution rate of oil production and the length of the outer zone for the first 30 years at different permeability of the outer zone. When the outer zone length is less than 20m, the oil production contribution rate of different outer zone permeabilities increases with the increase of the outer zone length at the same rate; when the length of the outer zone is more than 20m, the higher the permeability of the outer zone is, the higher the oil production contribution rate is; the greater the outer zone length, the more gradual the oil production contribution rate curve increases with the outer zone length. By combining fig. 11 and fig. 12, under the condition of 30 years of production, the larger the outer area range is, the larger the contribution to productivity is, and the main concentration is still within the first 60 meters; the greater the outer zone/inner zone permeability ratio, the greater the contribution to capacity.
Aiming at the shale condensate gas well of the hawk beach group, the influence rule of the outer zone on the productivity is as follows:
(1) The outer region has a certain contribution to the productivity, but the contribution value is not large;
(2) The larger the outer zone permeability value, the greater the contribution to capacity;
(3) The larger the outer zone, the greater the contribution to capacity;
(4) In the early production period (5 years), the outer region within 40m has a certain contribution to the productivity and mainly has a contribution within 20 m; the larger the outer zone, the greater the contribution to capacity, but mainly concentrated within the first 40-60 meters, for 30 years of production.
Advice for optimization of the pit spacing in mining sites:
(1) When the well spacing is optimized, the range of the outer region can be properly considered, but the range is not excessively large and is controlled within 20m as much as possible;
(2) Reasonable well spacing is less than or equal to 2 x (y) F +20m)。
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (7)
1. The method for analyzing the volumetric fracturing outer zone productivity contribution of the shale gas condensate well is characterized by comprising the following steps of:
based on complex fracture network characteristics and oil-gas two-phase flow characteristics in the shale gas condensate well fracturing development process, establishing a mathematical physical model based on a tri-linear flow theory, wherein the model is used for equivalently treating the complex fracture network of the shale gas condensate well into a fracturing modification body, and the fracturing modification body comprises an artificial main fracture, a fracturing modification inner area and a fracturing modification outer area;
performing history fitting on the produced shale gas condensate well dynamics based on a mathematical physical model of a tri-linear flow theory to obtain typical shale and fracturing fracture parameters;
based on typical shale and fracturing fracture parameters, different fracturing transformation outer zone boundary lengths are analyzed, and under different fracturing transformation outer zone permeability conditions, the contribution degree of the fracturing transformation outer zone to productivity is given out, so that reasonable well spacing considering the fracturing transformation outer zone contribution degree is provided.
2. The method for analysis of volumetric frac out-of-zone capacity contribution of a shale gas condensate well of claim 1, wherein the mathematical physical model of the tri-linear flow theory is established based on the following assumptions:
the shale reservoir is of horizontal equal thickness, the horizontal well is positioned in the center of the reservoir, and the crack penetrates through the whole reservoir;
considering the compressibility of oil and gas, neglecting the compressibility of rock;
the adsorption and desorption of the gas are subject to a Langmuir single-layer adsorption model, and the adsorption mechanism of the condensate is not clear and is not considered independently;
the fluid consists of two components, namely oil and gas, the gas component only exists in the gas phase, and the oil component can exist in the oil phase and the gas phase at the same time.
3. The method for analysis of volumetric frac out-of-zone capacity contribution of a shale gas condensate well of claim 1, wherein the equation for the frac remodelling out-of-zone is:
the fracturing transformation outer region is a matrix region, and adsorption and desorption of gas are described by using Langmuir theory.
Wherein V is L Is Langerhans' volume; p (P) L Is Langerhans pressure; p is the pressure; v is the gas adsorption amount in the rock per unit volume;
the differential equation of the seepage of the oil and gas in the fracturing reforming outer zone is as follows:
gas composition:
oil component:
wherein k is Arg Is the relative permeability of the gas phase in the outer zone; k (k) Aro Relative permeability of the oil phase in the outer region; k (k) A Permeability for the outer zone matrix; phi (phi) A Porosity for the outer region matrix; s is S Ag Saturation of the outer zone with gas; s is S Ao Oil saturation for the outer zone; mu (mu) g Is the viscosity of the gas; mu (mu) o Is the viscosity of crude oil; b (B) g Is the gas volume coefficient; b (B) o Is the volume coefficient of crude oil; p is p A Is the outer zone pressure; t is the production time; r is R v The content of the dissolved condensate oil in the gas phase; v (V) L Is Langerhans' volume; p is p L Is Langerhans pressure; y is the coordinate direction.
4. The method of analyzing volumetric fracturing outer zone capacity contribution of a shale gas condensate well according to claim 3, wherein the fracturing reconstruction inner zone is a dual medium, the medium is regarded as a flat plate by using an unsteady mass transfer model, and the influence on the adsorbed gas content refers to the fracturing reconstruction outer zone, so that a flow equation in a matrix is as follows:
gas composition:
oil component:
wherein k is mrg Is the relative permeability of the gas phase in the inner zone matrix; k (k) mro Relative permeability of oil phase in the inner zone matrix; k (k) m Permeability for the inner zone matrix; phi (phi) m Porosity for the inner zone matrix; s is S mg Saturation of the gas in the inner zone matrix; s is S mo Saturation of oil in the inner zone matrix; p is p m Is the internal zone matrix pressure; z is the coordinate direction.
5. The method for analysis of volumetric frac out-of-zone capacity contribution of a shale gas condensate well of claim 4, wherein the flow equation in the matrix is:
gas composition:
oil component:
wherein k is frg The relative permeability in the secondary fracture of the inner zone; k (k) fro The relative permeability of the oil phase in the secondary cracks of the inner zone; k (k) f The permeability of secondary cracks in the inner zone; phi (phi) f Secondary fracture porosity for the inner zone; s is S fg The saturation of gas in the secondary cracks of the inner zone; s is S fo The saturation of oil in the secondary crack of the inner zone; p is p f The secondary fracture pressure in the inner zone; q gmf Flow of the inner zone matrix system into the unit volume of the secondary fracture per unit timeGas mass; q gAf The mass of the gas flowing into the unit volume of the secondary crack for the matrix system in the inner area and the outer area in unit time; x is the coordinate direction.
6. The method for analysis of volumetric frac out-of-zone capacity contribution of a shale gas condensate well of claim 5, wherein considering fluid exchange from a frac-remodelled inner zone fracture to an artificial fracture, the percolation equation in the artificial fracture is:
gas composition:
oil component:
wherein k is Frg Relative permeability in the artificial fracture; k (k) Fro The relative permeability of the oil phase in the artificial fracture; k (k) F Is the permeability of the artificial crack; phi (phi) F Is the porosity of the artificial crack; s is S Fg The gas saturation in the artificial crack; s is S Fo The saturation degree of oil in the artificial crack; p is p F Is the pressure of the artificial crack; q gfF The mass of gas flowing into the artificial crack in unit volume from the secondary crack in unit time; q ofF The mass of crude oil flowing into the artificial fracture in unit volume from the secondary fracture in unit time; x is the coordinate direction.
7. The shale gas condensate well volumetric frac out-of-zone capacity contribution analysis method of claim 5, wherein typical shale and frac fracture parameters comprise: the crack is half-long, the secondary crack permeability, the inner/outer region matrix permeability, the artificial joint flow conductivity and the matrix block width of the fracturing transformation inner region.
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| CN116579263A (en) * | 2023-05-17 | 2023-08-11 | 中国石油大学(北京) | Comprehensive analysis method based on oil and gas well drainage dynamic data |
| CN116629165A (en) * | 2023-07-24 | 2023-08-22 | 中国石油大学(华东) | Reservoir fracturing reconstruction area and non-reconstruction area parameter inversion method, system and equipment |
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| CN116579263A (en) * | 2023-05-17 | 2023-08-11 | 中国石油大学(北京) | Comprehensive analysis method based on oil and gas well drainage dynamic data |
| CN116579263B (en) * | 2023-05-17 | 2024-01-30 | 中国石油大学(北京) | Comprehensive analysis method based on oil and gas well drainage dynamic data |
| CN116629165A (en) * | 2023-07-24 | 2023-08-22 | 中国石油大学(华东) | Reservoir fracturing reconstruction area and non-reconstruction area parameter inversion method, system and equipment |
| CN116629165B (en) * | 2023-07-24 | 2023-09-22 | 中国石油大学(华东) | Reservoir fracturing reconstruction area and non-reconstruction area parameter inversion method, system and equipment |
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