CN111553504A - Method and system for calculating volume of fracturing modified oil and gas reservoir - Google Patents
Method and system for calculating volume of fracturing modified oil and gas reservoir Download PDFInfo
- Publication number
- CN111553504A CN111553504A CN201910062347.1A CN201910062347A CN111553504A CN 111553504 A CN111553504 A CN 111553504A CN 201910062347 A CN201910062347 A CN 201910062347A CN 111553504 A CN111553504 A CN 111553504A
- Authority
- CN
- China
- Prior art keywords
- event
- microseism
- subdivision
- tetrahedron
- volume
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
- G06Q10/00—Administration; Management
- G06Q10/04—Forecasting or optimisation specially adapted for administrative or management purposes, e.g. linear programming or "cutting stock problem"
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
- G06Q50/00—Systems or methods specially adapted for specific business sectors, e.g. utilities or tourism
- G06Q50/02—Agriculture; Fishing; Mining
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T17/00—Three dimensional [3D] modelling, e.g. data description of 3D objects
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T7/00—Image analysis
- G06T7/60—Analysis of geometric attributes
- G06T7/62—Analysis of geometric attributes of area, perimeter, diameter or volume
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T2207/00—Indexing scheme for image analysis or image enhancement
- G06T2207/10—Image acquisition modality
- G06T2207/10028—Range image; Depth image; 3D point clouds
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Business, Economics & Management (AREA)
- Theoretical Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Strategic Management (AREA)
- Economics (AREA)
- Human Resources & Organizations (AREA)
- Geometry (AREA)
- General Business, Economics & Management (AREA)
- Tourism & Hospitality (AREA)
- Marketing (AREA)
- Health & Medical Sciences (AREA)
- Entrepreneurship & Innovation (AREA)
- General Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Marine Sciences & Fisheries (AREA)
- Animal Husbandry (AREA)
- Development Economics (AREA)
- Game Theory and Decision Science (AREA)
- Primary Health Care (AREA)
- Operations Research (AREA)
- Quality & Reliability (AREA)
- Computer Graphics (AREA)
- Agronomy & Crop Science (AREA)
- Software Systems (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Management, Administration, Business Operations System, And Electronic Commerce (AREA)
Abstract
The invention discloses a method for calculating the volume of a fracturing modified oil-gas reservoir, which comprises the following steps: acquiring the occurrence time of each defined microseism event point in the microseism monitoring data, determining the time position of each occurrence time in the fracturing modification process, and excluding the corresponding microseism event point under the conditions of natural cracks and unknown disturbance on the basis of the time position to form a primary microseism event cloud representing the effective fracturing modification volume; carrying out tetrahedral subdivision on the primary microseism event cloud to obtain a microseism optimization event subdivision model; and calculating the volume of each tetrahedron formed by the microseism event points in the microseism optimization event subdivision model, and further obtaining an estimation result of the volume of the fractured and reformed oil and gas reservoir according to the volume of each tetrahedron. The method effectively reduces the proportion of invalid volume in the reconstructed oil and gas reservoir volume, and improves the effectiveness and accuracy of volume fracturing operation evaluation.
Description
Technical Field
The invention relates to the field of petroleum development and exploration, in particular to a method and a system for calculating the volume of a fracturing modified oil-gas reservoir.
Background
Shale gas has become an important unconventional natural gas resource which is concerned by various countries, so that the shale gas exploration and development are enhanced, the resource structure of China can be directly optimized, and the energy supply is ensured. However, because the shale has the ultra-low permeability characteristic, the shale gas yield needs to be improved by means of large-range staged volume fracturing, and commercial exploitation is realized, so that the estimation of the productivity by means of the volume fracturing effect is a crucial step in the development process of oil and gas reservoirs. For traditional oil reservoirs, the target of fracturing effect evaluation is usually realized by adopting main fracture half-length data, but for unconventional oil and gas reservoirs represented by shale gas, a plurality of domestic and foreign research results fully indicate that volume fracturing operation causes a large fracture network instead of a complex fracture form of a single main fracture, so the traditional data of fracture half-length is not suitable for post-evaluation work of the shale gas reservoir volume fracturing effect. Aiming at the problem, the industry provides a concept of transforming the Volume of the oil and gas Reservoir (SRV), the parameter can directly quantify the effective oil drainage Volume of the Reservoir, and a great deal of practice proves that the method has strong applicability in the aspects of fracturing evaluation and capacity estimation of the shale gas Reservoir Volume.
Estimation of SRV relies primarily on microseismic survey data. The microseism technology is an indispensable technology for the current unconventional oil and gas development, and mainly utilizes the tiny seismic waves generated by underground stress fields changed by volume fracturing to describe hydraulic fracturing fractures or detect reservoir fluid movement by positioning microseism events. We generally consider that the volume included by a microseismic event cloud (event cloud) can be approximately equal to the volume modified by a fracture network, so computing the three-dimensional volume formed by the microseismic event cloud is almost the only way to quantify SRV at present. However, there is a few domestic patents discussing how to efficiently calculate the SRV.
In the prior art, all microseism events are generally wrapped simply by means of rectangles or spheres, the proportion of ineffective volumes in the SRV is often overlarge by the simple wrapping method, so that the volume fracturing reconstruction effect is overestimated excessively, the difference between the evaluation result of the reconstructed fracturing volume and the actual situation is large, and the accuracy of volume estimation result calculation is reduced.
Disclosure of Invention
In order to solve the technical problem, the invention provides a method for calculating the volume of a fracture-modified hydrocarbon reservoir, which comprises the following steps: acquiring the occurrence time of each defined microseism event point in microseism monitoring data, determining the time position of the occurrence time of each microseism event point in the fracturing modification process, and excluding the corresponding microseism event point under the conditions of natural cracks and unknown disturbance on the basis of the time position to form a primary microseism event cloud representing an effective fracturing modification volume; step two, performing tetrahedral subdivision on the primary microseism event cloud to obtain a microseism optimization event subdivision model; and step three, calculating the volume of each tetrahedron formed by the microseism event points in the microseism optimization event subdivision model, and further obtaining an estimation result of the volume of the fractured and reformed oil and gas reservoir according to the volume of each tetrahedron.
Preferably, in the first step, each micro-seismic event point is sequenced according to occurrence time, and a time window type corresponding to the occurrence time of each micro-seismic event point is determined according to a fracturing modification process flow; and reserving all the micro-seismic event points which are determined to be closed time windows to form the current primary micro-seismic event cloud.
Preferably, in the third step, the position of each microseism event point in the microseism optimization event subdivision model is obtained, and based on the position, the vertex coordinates of each subdivision tetrahedron contained in the microseism optimization event subdivision model are obtained; and calculating the ridge length of each subdivision tetrahedron according to the vertex coordinates of each subdivision tetrahedron, and calculating the volume of each subdivision tetrahedron based on the ridge length.
Preferably, in the second step, a Delaunay tetrahedron subdivision algorithm based on a point-by-point insertion method is adopted to perform tetrahedron subdivision processing on the primary microseismic event cloud; and carrying out local optimization on the tetrahedron subdivision processing result by utilizing a Delaunay tetrahedron subdivision criterion to obtain the microseism optimization event subdivision model.
Preferably, in the tetrahedron splitting processing step of the primary micro-seismic event cloud by using a Delaunay tetrahedron splitting algorithm based on a point-by-point interpolation method, the processing step includes: defining an initial tetrahedral network capable of containing all microseismic event points in the initial microseismic event cloud; inserting the microseism event points in the initial microseism event cloud into the initial tetrahedral network one by one, positioning the position of each microseism event point in the initial tetrahedral network, and further obtaining a first result aiming at the initial tetrahedral network; and connecting each newly inserted micro-seismic event point in the first result with four micro-seismic event end points of the tetrahedron to generate a tetrahedron subdivision processing result.
In another aspect, the present invention further provides a system for calculating a volume of a fracture modified reservoir, the system comprising: the primary optimization processing module is used for acquiring the occurrence time of each defined microseism event point in the microseism monitoring data, determining the time position of the occurrence time of each microseism event point in the fracturing modification process, and eliminating the corresponding microseism event point under the conditions of natural fracture and unknown disturbance based on the time position to form a primary microseism event cloud representing the effective fracturing modification volume; the secondary optimization processing module is used for carrying out tetrahedral subdivision on the primary microseism event cloud to obtain a microseism optimization event subdivision model; and the modified volume calculation module is used for calculating the volume of each tetrahedron formed by the microseism event points in the microseism optimization event subdivision model and further obtaining the estimation result of the volume of the fractured modified oil and gas reservoir according to the volume of each tetrahedron.
Preferably, the primary optimization processing module comprises: the time window type generating unit is used for sequencing each micro-seismic event point according to occurrence time and determining a time window type corresponding to the occurrence time of each micro-seismic event point according to a fracturing transformation process flow; and the primary optimization result generation unit is used for reserving all the micro-seismic event points which are determined to be closed time windows to form the current primary micro-seismic event cloud.
Preferably, the remodeling volume calculating module includes: the computation preprocessing unit is used for acquiring the position of each microseism event point in the microseism optimization event subdivision model and obtaining the vertex coordinates of each subdivision tetrahedron contained in the microseism optimization event subdivision model based on the position of each microseism event point; and a tetrahedron calculation unit which calculates each ridge length of the corresponding subdivision tetrahedron according to the vertex coordinates of each subdivision tetrahedron, and calculates the volume of each subdivision tetrahedron based on the ridge length.
Preferably, the quadratic optimization processing module includes: the tetrahedron subdivision processing unit is used for carrying out tetrahedron subdivision processing on the primary microseism event cloud by adopting a Delaunay tetrahedron subdivision algorithm based on a point-by-point insertion method; and the local optimization processing unit is used for carrying out local optimization on the tetrahedron subdivision processing result by utilizing a Delaunay tetrahedron subdivision criterion to obtain the microseism optimization event subdivision model.
Preferably, the tetrahedron subdivision processing unit includes: an initial tetrahedral generation subunit defining an initial tetrahedral network capable of containing all the microseismic event points in the initial microseismic event cloud; a first result generation subunit, which inserts each micro-seismic event point belonging to the initial micro-seismic event cloud into the initial tetrahedral network one by one, locates the position of each micro-seismic event point in the initial tetrahedral network, and further obtains a first result for the initial tetrahedral network; and a tetrahedron subdivision processing result generation subunit, configured to join, for each newly inserted microseismic event point in the first result, the newly inserted microseismic event point with four microseismic event endpoints of the tetrahedron, so as to generate a tetrahedron subdivision processing result.
Compared with the prior art, one or more embodiments in the above scheme can have the following advantages or beneficial effects:
the invention provides a method and a system for calculating the volume of a fracturing modified oil-gas reservoir. The method and the system utilize the time and position information of the microseism event point of the microseism fracturing detection data to realize the accurate calculation of the fracturing modification volume, effectively reduce the proportion of invalid volume in the SRV, improve the effectiveness and accuracy of volume fracturing evaluation by utilizing the SRV, help an oil reservoir engineer to evaluate the effect after fracturing modification and estimate the capacity after fracturing modification.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from 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 is a step diagram of a method of calculating a fracture-reformed reservoir volume according to an embodiment of the present application.
Fig. 2 is a specific flowchart of a method for calculating a fracture-modified reservoir volume according to an embodiment of the present application.
Fig. 3 is a schematic diagram of the original micro-seismic event clouds for two intervals in a method of computing a fracture reformed reservoir volume according to an embodiment of the application.
Fig. 4 is a schematic diagram of a microseismic optimization event subdivision model of two intervals in the method for calculating a fracture-modified reservoir volume according to the embodiment of the present application.
Fig. 5 is a block diagram of a system for calculating a fracture modification reservoir volume according to an embodiment of the present application.
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.
Shale gas has become an important unconventional natural gas resource which is concerned by various countries, so that the shale gas exploration and development are enhanced, the resource structure of China can be directly optimized, and the energy supply is ensured. However, because the shale has the ultra-low permeability characteristic, the shale gas yield needs to be improved by means of large-range staged volume fracturing, and commercial exploitation is realized, so that the estimation of the productivity by means of the volume fracturing effect is a crucial step in the development process of oil and gas reservoirs. For traditional oil reservoirs, the target of fracturing effect evaluation is usually realized by adopting main fracture half-length data, but for unconventional oil and gas reservoirs represented by shale gas, a plurality of domestic and foreign research results fully indicate that volume fracturing operation causes a large fracture network instead of a complex fracture form of a single main fracture, so the traditional data of fracture half-length is not suitable for post-evaluation work of the shale gas reservoir volume fracturing effect. Aiming at the problem, the industry provides a concept of transforming the Volume of the oil and gas Reservoir (SRV), the parameter can directly quantify the effective oil drainage Volume of the Reservoir, and a great deal of practice proves that the method has strong applicability in the aspects of fracturing evaluation and capacity estimation of the shale gas Reservoir Volume.
Estimation of SRV relies primarily on microseismic survey data. The microseism technology is an indispensable technology for the current unconventional oil and gas development, and mainly utilizes the tiny seismic waves generated by underground stress fields changed by volume fracturing to describe hydraulic fracturing fractures or detect reservoir fluid movement by positioning microseism events. We generally consider that the volume included by a microseismic event cloud (event cloud) can be approximately equal to the volume modified by a fracture network, so computing the three-dimensional volume formed by the microseismic event cloud is almost the only way to quantify SRV at present. However, there is a few domestic patents discussing how to efficiently calculate the SRV.
In the prior art, all microseism events are generally wrapped simply by means of rectangles or spheres, the proportion of ineffective volumes in the SRV is often overlarge by the simple wrapping method, so that the volume fracturing reconstruction effect is overestimated excessively, the difference between the evaluation result of the reconstructed fracturing volume and the actual situation is large, and the accuracy of volume estimation result calculation is reduced.
In order to solve the problems in the prior art, the invention provides a method and a system for calculating the volume of a fracturing modified oil-gas reservoir. The method and the system determine the time window type of each micro-seismic event point according to well section distribution conditions and a fracturing modification process by using the time and position information of each defined micro-seismic event point in original micro-seismic monitoring data, then sequentially perform tetrahedral subdivision processing (namely three-dimensional triangulation processing) and local optimization processing on a primary micro-seismic event cloud, and further obtain a micro-seismic optimized event subdivision model representing the actual effective fracturing volume, so that the volume of the optimized event subdivision model is obtained by using the position coordinates of each micro-seismic event point in the optimized event subdivision model, and the volume of a fracturing modification oil-gas reservoir for the current well to be measured or a certain well section is represented. The method mainly depends on a Delaunay tetrahedron subdivision method (namely, a Delaunay three-dimensional triangulation method) of the microseism event cloud to effectively reduce the proportion of invalid volume in the process of calculating and reforming the volume of the oil and gas reservoir and improve the effectiveness and accuracy of evaluating the volume fracturing operation effect by using the SRV.
Example one
Fig. 1 is a step diagram of a method of calculating a fracture-reformed reservoir volume according to an embodiment of the present application. As shown in fig. 1, first, step S110 obtains the occurrence time of each defined micro-seismic event point in the micro-seismic monitoring data, determines the time position of the occurrence time of each micro-seismic event point in the fracture reformation process, excludes the corresponding micro-seismic event point under the conditions of natural fracture and unknown disturbance, and forms a primary micro-seismic event cloud representing the effective fracture reformation volume. And then, in step S120, carrying out tetrahedral subdivision on the obtained primary microseism event cloud to obtain a microseism optimization event subdivision model. Next, in step S130, the volume of each tetrahedron formed by the microseismic event points in the microseismic optimized event subdivision model is calculated, and further an estimation result of the volume of the fracture modified hydrocarbon reservoir is obtained according to the volume of each tetrahedron. According to the technical scheme, firstly, the problem of representing the volume fracturing effect is equivalent to calculating the volume of the minimum convex polygon enclosed by all micro-seismic event points; and secondly, acquiring the convex polygon by adopting a tetrahedron subdivision mode, effectively reducing the proportion of invalid volume in the SRV through event point elimination and local optimization processing processes under the conditions of natural cracks and unknown disturbance, and improving the effectiveness and accuracy of volume fracturing evaluation by utilizing the SRV. Furthermore, the method helps a reservoir engineer to evaluate the effect after fracturing modification so as to estimate the capacity after fracturing modification.
Fig. 2 is a specific flowchart of a method for calculating a fracture-modified reservoir volume according to an embodiment of the present application. The specific process in steps S110 to S130 will be described in detail with reference to fig. 1 and 2.
In the actual fracturing operation effect evaluation process, micro-seismic monitoring equipment is usually adopted for a target well to be evaluated to obtain micro energy signals generated at fracture positions in the hydraulic fracturing process, and a plurality of micro-seismic event points, namely a time set and a corresponding position set of rock fracture, representing the fracture positions are obtained after processing, so that a micro-seismic event cloud is formed. Therefore, the micro-seismic monitoring equipment can describe the hydraulic fracturing fracture formed after the fracturing modification operation or detect the movement condition of the reservoir fluid after modification.
In the practical application process, each micro-seismic event point defined by the micro-seismic monitoring equipment has micro-seismic event points defined due to natural crack formation or some unknown disturbance and the like, and the micro-seismic event points cannot reflect the rock breaking condition in the fracturing modification process, so that the isolated points need to be eliminated in the process of evaluating the volume of the practical and effective fracturing modification oil and gas reservoir, and an effective micro-seismic event point set without the isolated points, namely a primary micro-seismic event cloud, which can reflect the fracturing modification volume is obtained. In the embodiment of the invention, an event cloud formed by each defined micro-seismic event point (including isolated points) in the micro-seismic monitoring data acquired by the micro-seismic monitoring equipment is called as an original micro-seismic event cloud.
Specifically, step S111 acquires time information of all the defined microseismic event points in the microseismic monitoring data. The microseism monitoring data can reflect the fracturing modification condition of a corresponding fracturing well section after a target modification reservoir carries out fracturing modification operation on a certain fracturing section, and corresponding microseism wave feedback data representing a plurality of corresponding microseism event points in the modification range of the current well section are defined in the current fracturing well section. Further, time information and position information of all micro-seismic event points in the original micro-seismic event cloud can be obtained according to micro-seismic feedback data (namely micro-seismic monitoring data) obtained by micro-seismic monitoring equipment and aiming at each defined micro-seismic event point in the modified well section, and all the time information and the position information are used as data processing objects for estimating the volume of the fractured modified hydrocarbon reservoir in the embodiment of the invention.
Fig. 3 is a schematic diagram of the original micro-seismic event clouds for two intervals in a method of computing a fracture reformed reservoir volume according to an embodiment of the application. As shown in fig. 3, the set of black points represents the microseismic event points defined by one of the fractured intervals in the original cloud of microseismic events in the target reservoir; the set of gray points represents the microseismic event points defined by another fractured well segment in the original cloud of microseismic events in the target reservoir.
And then, in step S112, sequencing each micro-seismic event point in a certain fracturing section according to occurrence time, and determining a time window type corresponding to the occurrence time of each micro-seismic event point according to the fracturing modification process flow. In the actual implementation process of the micro-seismic technology, corresponding micro-seismic emission operation needs to be carried out at a certain fracturing well section in the target reconstruction reservoir so as to monitor the fracturing reconstruction effect. Further, the time window type represents a type summarized by process characteristics corresponding to the time position of the current micro-seismic event point occurrence time in the fracturing reformation process.
Specifically, after each microseism event point is subjected to time sequencing, the whole fracturing transformation process is divided into three stages according to a fracturing transformation process, and each stage corresponds to a corresponding time window type, so that each stage (time window) comprises a plurality of corresponding microseism event points. Wherein, the time window type is divided into three types: a front window, a proppant window, and a closure window. It should be noted that the micro-seismic event points in the pre-time window represent micro-seismic event points occurring during the pumping of the pre-fluid; the microseismic event points within the proppant time window represent microseismic events that occurred during the pumping of the proppant carrier fluid; the microseismic event points within the closed time window represent microseismic events after the sand-carrying fluid (before back-discharge) was pumped in.
Next, in step S113, all the micro-seismic event points that have been determined to be closed time windows are retained, and the current primary micro-seismic event cloud is formed. Specifically, the micro-seismic events in the closed time window do not contain micro-seismic event points defined under the conditions of natural fracture formation, some unknown disturbances and the like, so that the micro-seismic event points in the time window can better reflect the geometric distribution condition of the effective fracture network of hydraulic fracturing, the calculation of the fracturing volume is optimized, and the accuracy of prediction of the effective fracturing reconstruction volume is improved. Further, according to the determination result of the time window type of each micro-seismic event point in the step S112, only the micro-seismic event points in the closed time window are reserved, and a micro-seismic event cloud which can effectively reflect the fracture transformation volume is formed.
And then, in step S121, performing tetrahedral subdivision on the current primary microseismic event cloud by using a Delaunay tetrahedral subdivision algorithm based on a point-by-point insertion method.
Specifically, in step S121, first, an initial tetrahedral network is defined which can include all the microseismic event points in the initial microseismic event cloud corresponding to the current fracture zone. And then, inserting each micro-seismic event point belonging to the current initial micro-seismic event cloud into the initial tetrahedral network one by one, positioning the position of each micro-seismic event point in the initial tetrahedral network, and obtaining a tetrahedral positioning result, namely a first result, for the initial tetrahedral network after completing the positioning operation for each micro-seismic event point. Wherein the positioning operation for each microseism event point is executed according to the following flow: and selecting any tetrahedron from the tetrahedron set in the current initial tetrahedron network, judging the position relationship between the currently selected tetrahedron and the currently inserted microseism event point, and determining the position of the current microseism event point in the initial tetrahedron according to the position relationship so as to finish the positioning operation. Further, if the currently inserted microseism event point is in the currently selected tetrahedron, the calculation is finished; otherwise, calculating the distance between the gravity center of each adjacent tetrahedron of the currently selected tetrahedron and the insertion event point, comparing and selecting the adjacent tetrahedron corresponding to the shortest distance, taking the adjacent tetrahedron as the optimal adjacent tetrahedron, and taking the position relation between the current insertion event point and the optimal adjacent tetrahedron as the calculation result of the positioning operation. Therefore, by using the method, the tetrahedron to be found can be gradually approached, and the target tetrahedron positioning is finally realized to obtain the corresponding first result.
And then, aiming at each newly inserted micro-seismic event point in the first result, connecting the newly inserted micro-seismic event point with four micro-seismic event end points of the tetrahedron to generate a new tetrahedron, so that a new tetrahedron formed by the subdivision tetrahedron taking each newly inserted micro-seismic event point as an end point is generated, and the new tetrahedron is the tetrahedron subdivision processing result.
And finally, in the step S122, local optimization is carried out on the tetrahedron subdivision processing result by utilizing a Delaunay tetrahedron subdivision criterion, so that a microseism optimization event subdivision model is obtained. Specifically, it is determined whether each of the subdivision tetrahedrons in the tetrahedron subdivision processing result of step S121 satisfies a Delaunay tetrahedron subdivision criterion, and according to the determination result, the tetrahedron subdivision processing result is locally optimized to obtain a Delaunay tetrahedron subdivision result, that is, a microseism optimization event subdivision model. If the current subdivision tetrahedron does not accord with the Delaunay tetrahedron subdivision criterion, optimizing the current subdivision tetrahedron by adopting a three-dimensional flip optimization method, and further, if an auxiliary point is added in the optimization process, deleting the auxiliary point. Finally, after each subdivision tetrahedron is judged, a Delaunay tetrahedron subdivision result (a microseismic optimized event subdivision model) formed by connecting all microseismic event points can be obtained. According to the technical scheme, the subdivision model comprises a plurality of subdivision tetrahedrons inside, and the end point of each subdivision tetrahedron is the microseism event point belonging to the closed time window.
Fig. 4 is a schematic diagram of a microseismic optimization event subdivision model of two intervals in the method for calculating a fracture-modified reservoir volume according to the embodiment of the present application. Fig. 4a shows the three-dimensional microseism optimization event subdivision model of the two fractured well sections, fig. 4b, fig. 4c and fig. 4d respectively show the three-view effect graphs of the three-dimensional microseism optimization event subdivision model of the two fractured well sections, wherein the black part represents the microseism optimization event subdivision model of one of the fractured well sections and the corresponding three views; the set of gray points represents the microseismic optimization event segmentation model and corresponding three views for another fractured interval.
Therefore, the problem of effectively reflecting the solving of the fracturing reconstruction volume is directly converted into the problem of calculating the volume of the minimum convex polygon enclosed by all microseism event points through the tetrahedron subdivision treatment and the local optimization treatment, and the calculation process of the reconstruction volume is simplified.
After the micro-seismic event points in the original micro-seismic event cloud are reserved in the closed time window, the tetrahedral subdivision conversion and the local optimization processing are carried out, the optimal micro-seismic optimized event subdivision model equivalent to the estimated volume of the fractured and reformed oil and gas reservoir is obtained, and then the step S130 is carried out, and the volume of a convex polygon formed by all the micro-seismic event points in the optimized event subdivision model is obtained.
Specifically, in step S131, the position of each microseismic event point in the microseismic optimized event subdivision model currently obtained in step S122 is obtained, and based on this, the vertex coordinates of each subdivision tetrahedron included in the microseismic optimized event subdivision model are obtained. After the tetrahedron subdivision and optimization processing of the step S122 is completed, the microseism optimized event subdivision model is already divided into a plurality of tetrahedrons formed by each microseism event point, and the vertex of each tetrahedron in the model is the microseism event point in the closed time window, and the vertex coordinates of each subdivision tetrahedron in the microseism optimized event subdivision model are determined according to the position information of the microseism event points.
Then, step S132 is carried out, the edge length of each subdivision tetrahedron is calculated according to the vertex coordinates of each subdivision tetrahedron in the micro-seismic optimization event subdivision model, and the volume of each tetrahedron is obtained by further utilizing an edge length-volume calculation formula. Wherein, the flute length-volume calculation formula is expressed by the following expression:
in the formula (1), a, b, c, d, e, and f respectively represent the ridge length of the current tetrahedron, and V represents the volume of the current tetrahedron, and then the process proceeds to step S133.
Step S133, according to the volume result of each subdivision tetrahedron included in the microseism optimization event subdivision model in the step S132, summing the volumes of each subdivision tetrahedron to obtain a final volume of the microseism optimization event subdivision model, so as to represent the effect of volume fracturing operation of a certain fracturing section.
In the practical application process, the SRV of the fracture-modified oil and gas reservoir volume calculated by the method of the embodiment of the invention at a certain fracture section is 20268m3And the SRV obtained by adopting a basic cuboid wrapping method and a box separation method is 29370m respectively3And 23454m3. Compared with the most basic cuboid wrapping method algorithm, the SRV of the calculation result obtained by the method is reduced by 31%, and compared with a box separation method, the SRV is reduced by 15%. The main reason is that the algorithm effectively avoids the interference of invalid volumes in the original microseismic event cloud to the SRV calculation.
Example two
On the other hand, the invention also provides a system for calculating the volume of the fracturing modified oil-gas reservoir. Fig. 5 is a block diagram of a system for calculating a fracture modification reservoir volume according to an embodiment of the present application. As shown in fig. 5, the system includes a primary optimization processing module 51, a secondary optimization processing module 52, and a reconstruction volume calculation module 53 as follows. The primary optimization processing module 51 is implemented according to the method in step S110, and is configured to obtain the occurrence time of each defined micro-seismic event point in the micro-seismic monitoring data, determine the time position of the occurrence time of each micro-seismic event point in the fracture reformation process, exclude the corresponding micro-seismic event point under the conditions of natural fracture and unknown disturbance, and form a primary micro-seismic event cloud representing an effective fracture reformation volume. And a secondary optimization processing module, which is implemented according to the method in the step S120 and configured to perform tetrahedral subdivision on the primary microseismic event cloud to obtain a microseismic optimized event subdivision model. And a modified volume calculation module, which is implemented according to the method in the step S130, configured to calculate a volume of each tetrahedron formed by the microseismic event points in the microseismic optimized event subdivision model, and further obtain an estimation result of the volume of the fracture modified hydrocarbon reservoir according to the volume of each tetrahedron.
Specifically, the composition and function of each module in the system described above will be described below with reference to fig. 5.
The primary optimization processing module 51 further includes: a time acquisition unit 511, a time window type generation unit 512 and a primary optimization result generation unit 513. The time obtaining unit 511, implemented according to the method in step S111, is configured to obtain time information of all defined microseismic event points in the microseismic monitoring data. The time window type generating unit 512, which is implemented according to the method described in step S112, is configured to sort each micro-seismic event point in a certain fracture section according to occurrence time, and determine a time window type corresponding to the occurrence time of each micro-seismic event point according to the fracture transformation process flow. The primary optimization result generating unit 513, implemented according to the method described in step S113 above, is configured to retain all the micro-seismic event points that have been determined to be closed time windows, constituting a current primary micro-seismic event cloud.
The second optimization processing module 52 further includes: a tetrahedron subdivision processing unit 521 and a local optimization processing unit 522. The tetrahedron subdivision processing unit 521, which is implemented according to the method in step S121, is configured to perform tetrahedron subdivision processing on the primary microseismic event cloud obtained by the primary optimization result generating unit 515 by using a Delaunay tetrahedron subdivision algorithm based on a point-by-point interpolation method. The local optimization processing unit 522, which is implemented according to the method described in step S122 above, is configured to perform local optimization on the tetrahedron subdivision processing result by using the Delaunay tetrahedron subdivision criterion, so as to obtain the microseism optimization event subdivision model.
Further, the tetrahedron subdivision processing unit 521 further includes: an initial tetrahedron generation subunit 5211, a first result generation subunit 5212, and a tetrahedron subdivision processing result generation subunit 5213. Wherein the initial tetrahedron generation subunit 5211 is configured to define an initial tetrahedral network capable of containing all the microseismic event points in the initial microseismic event cloud described above. A first result generation subunit 5212, configured to insert each micro-seismic event point belonging to the initial micro-seismic event cloud into the current initial tetrahedral network one by one, locate the position of each micro-seismic event point in the initial tetrahedral network, and further obtain a tetrahedral location result (first result) for the initial tetrahedral network. A tetrahedron subdivision processing result generation subunit 5213, configured to join, for each newly inserted micro-seismic event point in the first result, the newly inserted micro-seismic event point with the four micro-seismic event end points of the tetrahedron in which it is located, and generate a tetrahedron subdivision processing result composed of a subdivision tetrahedron in which each newly inserted micro-seismic event point is an end point.
In addition, the modification volume calculation module 53 further includes: a calculation preprocessing unit 531, a tetrahedron calculation unit 532 and a modified reservoir volume generation unit 533. The calculation preprocessing unit 531, which is implemented according to the method in step S131, is configured to obtain the position of each microseism event point in the microseism optimized event subdivision model, and based on the position, obtain the vertex coordinates of each subdivision tetrahedron included in the microseism optimized event subdivision model. A tetrahedron calculation unit 532, which is implemented according to the method in step S132 above, configured to calculate each edge length of each subdivision tetrahedron according to the vertex coordinates of each subdivision tetrahedron in the microseism optimization event subdivision model, and calculate the volume of each subdivision tetrahedron by using the edge length-volume calculation formula represented by formula (1) above. The modified hydrocarbon reservoir volume generating unit 533, implemented according to the method in step S133, is configured to sum the volumes of each subdivision tetrahedron included in the microseism optimization event subdivision model to obtain a final volume of the microseism optimization event subdivision model, so as to represent the effect of volume fracturing operation of a certain fracturing segment.
The invention relates to a method and a system for calculating the volume of a fracturing modified oil-gas reservoir. According to the method and the system, an effective microseism event cloud capable of reflecting the fracturing reconstruction volume is obtained through a preliminary processing process of reserving microseism event points in a closed time window, the reconstruction volume evaluation problem is further converted into a volume solving problem of a minimum convex polygon enclosed by all microseism event points in the microseism event cloud through a Delaunay tetrahedron subdivision algorithm, the solved convex polygon is further locally optimized through a Delaunay tetrahedron subdivision criterion, and the optimized convex polygon volume is used for representing the evaluation effect of the SRV. The method effectively reduces the proportion of invalid volume in the SRV, and improves the effectiveness and accuracy of evaluating the volume fracturing by utilizing the SRV. By utilizing the time and position information of the microseism event point of the microseism fracturing detection data, the accurate calculation of the fracturing modification volume is realized, an oil reservoir engineer is helped to evaluate the fracturing modification effect, and the capacity estimation after fracturing modification is carried out.
The above description is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A method of calculating a fracture-reformed reservoir volume, the method comprising:
acquiring the occurrence time of each defined microseism event point in microseism monitoring data, determining the time position of the occurrence time of each microseism event point in the fracturing modification process, and excluding the corresponding microseism event point under the conditions of natural cracks and unknown disturbance on the basis of the time position to form a primary microseism event cloud representing an effective fracturing modification volume;
step two, performing tetrahedral subdivision on the primary microseism event cloud to obtain a microseism optimization event subdivision model;
and step three, calculating the volume of each tetrahedron formed by the microseism event points in the microseism optimization event subdivision model, and further obtaining an estimation result of the volume of the fractured and reformed oil and gas reservoir according to the volume of each tetrahedron.
2. The method of claim 1, wherein, in step one,
sequencing each micro-seismic event point according to occurrence time, and determining a time window type corresponding to the occurrence time of each micro-seismic event point according to a fracturing transformation process flow;
and reserving all the micro-seismic event points which are determined to be closed time windows to form the current primary micro-seismic event cloud.
3. The method according to claim 1 or 2, characterized in that, in step three,
acquiring the position of each microseism event point in the microseism optimization event subdivision model, and acquiring the vertex coordinates of each subdivision tetrahedron contained in the microseism optimization event subdivision model based on the position of each microseism event point;
and calculating the ridge length of each subdivision tetrahedron according to the vertex coordinates of each subdivision tetrahedron, and calculating the volume of each subdivision tetrahedron based on the ridge length.
4. A method according to any one of claims 1 to 3, wherein, in the second step,
performing tetrahedral subdivision processing on the primary microseism event cloud by adopting a Delaunay tetrahedral subdivision algorithm based on a point-by-point insertion method;
and carrying out local optimization on the tetrahedron subdivision processing result by utilizing a Delaunay tetrahedron subdivision criterion to obtain the microseism optimization event subdivision model.
5. The method according to claim 4, wherein in the step of tetrahedrally subdividing the cloud of primary microseismic events using a Delaunay tetrahedron subdivision algorithm based on a point-by-point interpolation method, the method comprises:
defining an initial tetrahedral network capable of containing all microseismic event points in the initial microseismic event cloud;
inserting the microseism event points in the initial microseism event cloud into the initial tetrahedral network one by one, positioning the position of each microseism event point in the initial tetrahedral network, and further obtaining a first result aiming at the initial tetrahedral network;
and connecting each newly inserted micro-seismic event point in the first result with four micro-seismic event end points of the tetrahedron to generate a tetrahedron subdivision processing result.
6. A system for calculating a fracture modification reservoir volume, the system comprising:
the primary optimization processing module is used for acquiring the occurrence time of each defined microseism event point in the microseism monitoring data, determining the time position of the occurrence time of each microseism event point in the fracturing modification process, and eliminating the corresponding microseism event point under the conditions of natural fracture and unknown disturbance based on the time position to form a primary microseism event cloud representing the effective fracturing modification volume;
the secondary optimization processing module is used for carrying out tetrahedral subdivision on the primary microseism event cloud to obtain a microseism optimization event subdivision model;
and the modified volume calculation module is used for calculating the volume of each tetrahedron formed by the microseism event points in the microseism optimization event subdivision model and further obtaining the estimation result of the volume of the fractured modified oil and gas reservoir according to the volume of each tetrahedron.
7. The system of claim 6, wherein the primary optimization processing module comprises:
the time window type generating unit is used for sequencing each micro-seismic event point according to occurrence time and determining a time window type corresponding to the occurrence time of each micro-seismic event point according to a fracturing transformation process flow;
and the primary optimization result generation unit is used for reserving all the micro-seismic event points which are determined to be closed time windows to form the current primary micro-seismic event cloud.
8. The system of claim 6 or 7, wherein the reform volume calculation module comprises:
the computation preprocessing unit is used for acquiring the position of each microseism event point in the microseism optimization event subdivision model and obtaining the vertex coordinates of each subdivision tetrahedron contained in the microseism optimization event subdivision model based on the position of each microseism event point;
and a tetrahedron calculation unit which calculates each ridge length of the corresponding subdivision tetrahedron according to the vertex coordinates of each subdivision tetrahedron, and calculates the volume of each subdivision tetrahedron based on the ridge length.
9. The system according to any one of claims 6 to 8, wherein the quadratic optimization processing module comprises:
the tetrahedron subdivision processing unit is used for carrying out tetrahedron subdivision processing on the primary microseism event cloud by adopting a Delaunay tetrahedron subdivision algorithm based on a point-by-point insertion method;
and the local optimization processing unit is used for carrying out local optimization on the tetrahedron subdivision processing result by utilizing a Delaunay tetrahedron subdivision criterion to obtain the microseism optimization event subdivision model.
10. The system of claim 9, wherein the tetrahedral subdivision processing unit comprises:
an initial tetrahedral generation subunit defining an initial tetrahedral network capable of containing all the microseismic event points in the initial microseismic event cloud;
a first result generation subunit, which inserts each micro-seismic event point belonging to the initial micro-seismic event cloud into the initial tetrahedral network one by one, locates the position of each micro-seismic event point in the initial tetrahedral network, and further obtains a first result for the initial tetrahedral network;
and a tetrahedron subdivision processing result generation subunit, configured to join, for each newly inserted microseismic event point in the first result, the newly inserted microseismic event point with four microseismic event endpoints of the tetrahedron, so as to generate a tetrahedron subdivision processing result.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910062347.1A CN111553504B (en) | 2019-01-23 | 2019-01-23 | Method and system for calculating volume of fracturing modified oil and gas reservoir |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910062347.1A CN111553504B (en) | 2019-01-23 | 2019-01-23 | Method and system for calculating volume of fracturing modified oil and gas reservoir |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111553504A true CN111553504A (en) | 2020-08-18 |
| CN111553504B CN111553504B (en) | 2022-06-03 |
Family
ID=72005428
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910062347.1A Active CN111553504B (en) | 2019-01-23 | 2019-01-23 | Method and system for calculating volume of fracturing modified oil and gas reservoir |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111553504B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105223611A (en) * | 2014-07-04 | 2016-01-06 | 中国石油化工股份有限公司 | Based on the pressure break reservoir leading edge of the three-dimensional point set of micro-seismic monitoring, area and calculation method of physical volume |
| US20170299742A1 (en) * | 2014-10-13 | 2017-10-19 | Halliburton Energy Services, Inc. | Improved data-driven estimation of stimulated reservoir volume |
| CN107832524A (en) * | 2017-11-07 | 2018-03-23 | 中国石油天然气股份有限公司 | A kind of method, apparatus and system for determining reservoir reconstruction volume |
-
2019
- 2019-01-23 CN CN201910062347.1A patent/CN111553504B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105223611A (en) * | 2014-07-04 | 2016-01-06 | 中国石油化工股份有限公司 | Based on the pressure break reservoir leading edge of the three-dimensional point set of micro-seismic monitoring, area and calculation method of physical volume |
| US20170299742A1 (en) * | 2014-10-13 | 2017-10-19 | Halliburton Energy Services, Inc. | Improved data-driven estimation of stimulated reservoir volume |
| CN107832524A (en) * | 2017-11-07 | 2018-03-23 | 中国石油天然气股份有限公司 | A kind of method, apparatus and system for determining reservoir reconstruction volume |
Non-Patent Citations (1)
| Title |
|---|
| 邵媛媛等: ""基于微地震事件点的SRV拟合方法比较研究"", 《西南石油大学学报(自然科学版)》 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111553504B (en) | 2022-06-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2945467C (en) | Enhancing reservoir characterization using real-time srv and fracture evolution parameters | |
| AU2013399602A1 (en) | Creating virtual production logging tool profiles for improved history matching | |
| EP2973429A1 (en) | Basin-to-reservoir modeling | |
| CN112901158A (en) | Hydraulic fracture length prediction method and fracture network modeling method and device | |
| CN111986321B (en) | Three-dimensional geological modeling method, device, equipment and storage medium | |
| CN111553504B (en) | Method and system for calculating volume of fracturing modified oil and gas reservoir | |
| CN111175817A (en) | Micro-seismic data-assisted compact oil and gas reservoir fracture distribution inversion method | |
| Ping et al. | Data assimilation method for fractured reservoirs using mimetic finite differences and ensemble Kalman filter | |
| CN110058298B (en) | Three-dimensional geologic body spatial interpolation method and system | |
| WO2018125133A1 (en) | Global surface paleo-temperature modeling tool | |
| US10241231B2 (en) | Method for exploiting a fractured medium on the basis of a matched reservoir model for wells chosen by means of an equivalent transmissivity model | |
| CA2994529A1 (en) | Time-to-finish simulation forecaster | |
| CN116862432A (en) | Dynamic adjustment method and system for tunnel shallow buried section construction scheme | |
| EP3186665B1 (en) | Method of characterising a subsurface volume | |
| CA2879063A1 (en) | Systems and methods for estimating opportunity in a reservoir system | |
| US20180306939A1 (en) | Correcting Biases In Microseismic-Event Data | |
| WO2015167507A2 (en) | Identifying correlations between stimulated reservoir volume parameters and fracture network parameters | |
| CN113495294B (en) | Quantitative characterization and evaluation method and device for sliding fracture | |
| Wang et al. | Prediction of sedimentary microfacies distribution by coupling stochastic modeling method in oil and gas energy resource exploitation | |
| US20240110472A1 (en) | Optimal drilling and fracturing sequences for placing numerous horizontal wells in tight reservoirs | |
| US11821301B2 (en) | Preventing cement casing failures based on casing acoustic impedance | |
| US20230127237A1 (en) | Integrating wells into adaptive multi-scale geological modeling | |
| Li et al. | Application of facies-controlled geostatistical inversion in research of Paleogene shale interbed: A case study in Bohai Bay | |
| CN110568492B (en) | Method for predicting residual oil distribution by using time-lapse seismic data | |
| CN108537470B (en) | Fitting method of ionic rare earth ore body |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |