阅读说明：本技术 一种基于深度学习的碳酸盐岩断缝洞结构地震表征方法 (Carbonate rock fracture-cave structure seismic characterization method based on deep learning ) 是由 张国印 林承焰 任丽华 孔凡静 李辉 于 2021-09-03 设计创作，主要内容包括：本发明涉及油气勘探与开发技术领域,公开了一种基于深度学习的碳酸盐岩断缝洞结构地震表征方法,所述方法包括：采用实际资料与模拟数据相结合的方法,分类构建断、缝、洞训练数据集；将断裂与溶洞地震识别作为三维图像分割问题,将裂缝地震识别作为回归问题,分类建立并训练断、缝、洞地震识别深度学习模型；将已训练的深度学习模型分别应用于研究区实际三维地震数据,得到断、缝、洞分类预测三维数据体；最终通过断、缝、洞分类预测结果的融合来表征断缝洞结构。本发明方法基于深度学习充分挖掘地震数据有效信息,实现真三维地震资料解释,可有效提高碳酸盐岩断缝洞结构地震表征的精度和可靠性。(The invention relates to the technical field of oil-gas exploration and development, and discloses a carbonate rock fracture-cave structure seismic characterization method based on deep learning, which comprises the following steps: constructing a training data set of fracture, seam and hole in a classified manner by adopting a method of combining actual data and simulation data; identifying fracture and karst cave earthquakes as three-dimensional image segmentation problems, identifying fracture earthquakes as regression problems, and establishing and training fracture, fracture and cave earthquake identification depth learning models in a classified manner; respectively applying the trained deep learning model to actual three-dimensional seismic data of a research area to obtain a three-dimensional data volume for classification prediction of fracture, seam and hole; and finally, representing the structure of the broken joint and the hole by fusing the classification and prediction results of the broken joint, the broken joint and the hole. The method fully excavates effective information of the seismic data based on deep learning, realizes true three-dimensional seismic data interpretation, and can effectively improve the accuracy and reliability of seismic representation of the carbonate fracture-cavity structure.)

1. An intelligent carbonate rock fracture-cave structure earthquake characterization method based on deep learning is characterized by comprising the following steps:

step 1, considering the geological and seismic data characteristics of a research area, and adopting a method of combining actual data and simulation data to construct a fracture, seam and hole training data set in a classified manner:

step 1.1, constructing a three-dimensional simulated fracture and forward modeling seismic data set;

step 1.2, constructing a three-dimensional simulated karst cave and forward seismic data set;

step 1.3, constructing a logging interpretation crack and a three-dimensional seismic data set beside a well;

step 2, establishing and training a fracture, seam and hole recognition deep learning model in a classified manner:

step 2.1, fracture identification is used as a three-dimensional image segmentation problem, three-dimensional forward seismic data is used as input, three-dimensional simulated fracture data is used as a label, a three-dimensional convolutional codec deep learning framework is built, a fracture data set is divided into a training set, a verification set and a test set, training and testing are repeatedly carried out on the three-dimensional convolutional codec, and model parameters are continuously optimized;

2.2, taking karst cave identification as a three-dimensional image segmentation problem, taking three-dimensional forward seismic data as input, taking three-dimensional simulated karst cave data as a label, building a three-dimensional convolutional codec deep learning framework, dividing a karst cave data set into a training set, a verification set and a test set, repeatedly training and testing the three-dimensional convolutional codec, and continuously optimizing model parameters;

step 2.3, using the crack identification as a regression fitting problem, using three-dimensional well-side seismic data as input, using logging identification crack data corresponding to the seismic data as a label, building a three-dimensional convolution network deep learning framework, dividing a crack data set into a training set, a verification set and a test set, repeatedly training and testing the model, and continuously optimizing model parameters;

and step 3: respectively applying the trained fault, seam and hole deep learning models to the three-dimensional seismic data of the actual research area to realize the classification prediction of the fault, seam and hole;

and 4, step 4: and fusing the earthquake classification prediction results of the fracture, the seam and the hole, and representing the fracture and hole structure in a plane, a section and a three-dimensional space.

2. The method for seismic characterization of a carbonate rock fracture-cavity structure based on deep learning as claimed in claim 1, wherein in step 1.1, the three-dimensional simulated fracture data includes fractures with different dip angles, tendencies, fracture distances and combinations, and on the basis, the fracture forward modeling three-dimensional seismic data is generated by stacking random noise through three-dimensional convolution.

3. The carbonate rock fracture-cave structure seismic characterization method based on deep learning of claim 1, wherein in step 1.2, the three-dimensional simulated karst cave data comprises ellipsoidal karst caves with different cave lengths, cave heights and aspect ratios, the physical properties of the karst caves and surrounding rock rocks are randomly simulated by a sequential Gaussian method, on the basis, the actual seismic data extraction wavelets are adopted to perform three-dimensional convolution operation, and random noise is superimposed to generate karst cave forward-evolution simulated three-dimensional seismic data.

4. The carbonate rock fracture-cave structure seismic characterization method based on deep learning of claim 1, wherein in the step 1.3, the well logging interpretation fracture data mainly refers to fracture development line density, porosity and the like of imaging well logging interpretation as tag data; the actual three-dimensional seismic data beside the well is extracted as input data, and meanwhile, various crack sensitive seismic attributes can be extracted as multi-channel input data.

5. The carbonate rock fracture-cave structure seismic characterization method based on deep learning of claim 1, wherein in the steps 2.1 and 2.2, the three-dimensional convolution coder and Decoder (Decoder) are formed, the coder is formed by a plurality of three-dimensional convolution layers, and the dimension of the output feature body is continuously reduced by controlling the convolution step length; the decoder is composed of a plurality of three-dimensional deconvolution layers and convolution layers, and the dimensionality of the output feature body is continuously increased by controlling the deconvolution step length; the generalization performance of the model was improved using a linear rectification function (ReLU) as the activation function, using a Dropout layer, using binary cross-entropy (binary cross-entropy) as the loss function, and Adam as the optimization function.

6. The carbonate rock fracture-cave structure seismic characterization method based on deep learning of claim 1, wherein in the step 2.3, the three-dimensional convolution network is composed of a plurality of three-dimensional convolution layers, a Dropout layer and a full-connection layer, the input is a three-dimensional seismic unit, the output is one-dimensional fracture density data, and mean squared error (mean squared error) is used as a loss function.

7. The carbonate rock fracture-cavity structure seismic characterization method based on deep learning as claimed in claim 1, wherein in the step 3, the prediction of the whole three-dimensional seismic data is gradually completed by applying the actual three-dimensional seismic data by adopting a multi-direction three-dimensional body window sliding method, so as to obtain a fracture, fracture and cavity classification prediction three-dimensional data body.

8. The carbonate rock fracture-gap-hole structure seismic characterization method based on deep learning as claimed in claim 1, wherein in the step 4, the fracture, gap and hole seismic classification prediction results are fused, and the fracture-gap-hole structure characterization results are obtained by adopting methods such as data merging operation, hollow superposition and transparent display.

Technical Field

The invention relates to the technical field of oil-gas exploration and development, in particular to a method for carrying out fracture-cavity structural seismic characterization on a carbonate fracture-control karst fracture-cavity type oil-gas reservoir.

Background

The karst fracture-cave type oil-gas reservoir with fracture control is an important oil-gas reservoir type discovered recently, particularly in Ordovician carbonate rocks in the north and middle deep layers of a Tarim basin, the fracture-cave type oil-gas reservoir controlled by large-scale sliding fracture develops widely, and has great oil-gas exploration and development potential. The fracture control karst fissure cavern takes fracture as a core, a fracture broken zone is formed under the action of structural stress, and a complex karst fissure cavern reservoir is formed after multi-stage atmospheric fresh water karst and deep hydrothermal solution corrosion modification, wherein the fracture control karst fissure cavern is extremely complex in structure.

The three-dimensional earthquake is an important means for characterizing the deep fracture-cavity structure, but the deep earthquake data has low resolution, the fracture-cavity reservoir types are various, the size difference is large, and the fracture-cavity structure earthquake characterization difficulty is large and the precision is low. "fracture, crack, cavity" refers to fracture, crack, karst cavity, respectively. The vertical fault distance of the sliding fracture is small, the seismic fracture response characteristic is weak, the difficulty of conventional manual interpretation is high, the seismic fracture response characteristic extracted by the existing seismic fracture identification method such as coherent body and variance body attributes is weak, the seismic fracture response characteristic is easy to be confused with seismic noise, and the sliding fracture identification effect is poor. The karst cave has large scale difference, various structures and combinations and complex seismic response characteristics, and the prior art mainly identifies by methods such as seismic amplitude attributes, such as root-mean-square amplitude, maximum amplitude, amplitude change rate and the like, but has larger identification errors on the structure, the form and the boundary of the karst cave. Due to the fact that the cracks are small in size, response of post-stack seismic data is weak, and the existing post-stack seismic methods such as ant tracking are low in crack identification well drilling verification accuracy.

In the prior art, the fracture, the seam and the hole are mainly identified by different seismic attribute methods, the identification precision is low, the fracture and hole structure is difficult to be represented finely, and the requirement for fine representation of the fracture-control karst fracture-hole type oil and gas reservoir exploration and development reservoir structure cannot be met. The invention provides a deep learning-based method for solving the problem of fine characterization of a fracture-fracture hole structure.

Disclosure of Invention

The invention provides a carbonate rock fracture-cave structure earthquake characterization method based on deep learning aiming at the limitation of the existing fracture-cave structure characterization technology, which can effectively improve the precision and reliability of the fracture-cave structure earthquake characterization, and the implementation steps comprise:

step 1, considering the geological and seismic data characteristics of a research area, and adopting a method of combining actual data and simulation data to construct a fracture, seam and hole training data set in a classified manner:

step 1.1, constructing a three-dimensional simulated fracture and forward modeling seismic data set;

step 1.2, constructing a three-dimensional simulated karst cave and forward seismic data set;

step 1.3, constructing a logging interpretation crack and a three-dimensional seismic data set beside a well;

step 2, establishing and training a fracture, seam and hole recognition deep learning model in a classified manner:

step 2.1, fracture identification is used as a three-dimensional image segmentation problem, three-dimensional forward seismic data is used as input, three-dimensional simulated fracture data is used as a label, a three-dimensional convolutional codec deep learning framework is built, a fracture data set is divided into a training set, a verification set and a test set, training and testing are repeatedly carried out on the three-dimensional convolutional codec, and model parameters are continuously optimized;

2.2, taking karst cave identification as a three-dimensional image segmentation problem, taking three-dimensional forward seismic data as input, taking three-dimensional simulated karst cave data as a label, building a three-dimensional convolutional codec deep learning framework, dividing a karst cave data set into a training set, a verification set and a test set, repeatedly training and testing the three-dimensional convolutional codec, and continuously optimizing model parameters;

step 2.3, using the crack identification as a regression fitting problem, using three-dimensional well-side seismic data as input, using logging identification crack data corresponding to the seismic data as a label, building a three-dimensional convolution network deep learning framework, dividing a crack data set into a training set, a verification set and a test set, repeatedly training and testing the model, and continuously optimizing model parameters;

and step 3: respectively applying the trained fault, seam and hole deep learning models to the three-dimensional seismic data of the actual research area to realize the classification prediction of the fault, seam and hole;

and 4, step 4: and fusing the earthquake classification prediction results of the fracture, the joint and the hole, and representing the fracture and hole structure in a plane, a section and a three-dimensional space.

In the above technical solution, in the step 1.1, the three-dimensional simulated fracture data includes fractures of different inclinations, tendencies, fracture distances and combinations, and on this basis, fracture forward-simulated three-dimensional seismic data is generated by stacking random noise through three-dimensional convolution.

In the above technical scheme, in the step 1.2, the three-dimensional simulated karst cave data includes ellipsoidal karst caves with different cave lengths, cave heights and aspect ratios, the physical attributes of the karst caves and surrounding rock are randomly simulated by a sequential gaussian method, on the basis, wavelets are extracted by using actual seismic data to perform three-dimensional convolution operation, and random noise is superimposed to generate karst cave forward simulated three-dimensional seismic data.

In the above technical solution, in the step 1.3, the well logging interpretation fracture data mainly refers to fracture development linear density, porosity, and the like of imaging well logging interpretation, and is used as tag data; the actual three-dimensional seismic data beside the well is extracted as input data, and meanwhile, various crack sensitive seismic attributes can be extracted as multi-channel input data.

In the above technical solutions, in the steps 2.1 and 2.2, the three-dimensional convolutional coder/Decoder is composed of an Encoder (Encoder) and a Decoder (Decoder), the Encoder is composed of a plurality of three-dimensional convolutional layers, and the dimension of the output feature is continuously reduced by controlling the convolutional step length; the decoder is composed of a plurality of three-dimensional deconvolution layers and convolution layers, the dimensionality of an output characteristic body is continuously increased by controlling the deconvolution step length, and the dimensionality of output data is the same as that of input data; the generalization performance of the model was improved using a linear rectification function (ReLU) as the activation function, using a Dropout layer, using binary cross-entropy (binary cross-entropy) as the loss function, and Adam as the optimization function.

In the above technical solution, in step 2.3, the three-dimensional convolution network is composed of a plurality of three-dimensional convolution layers, a Dropout layer, and a full connection layer, the input is a three-dimensional seismic unit, the output is one-dimensional fracture density data, and a mean squared error (mean squared error) is used as a loss function.

In the above technical scheme, in the step 3, in the application of the actual three-dimensional seismic data, the prediction of the whole three-dimensional seismic data is gradually completed by adopting a multi-direction three-dimensional body window sliding method, so as to obtain the classified prediction three-dimensional data body of the fracture, seam and hole.

In the above technical scheme, in the step 4, the fracture, seam and hole earthquake classification prediction results are fused, and the fracture and hole structure characterization results are obtained by adopting methods such as data merging operation, hollow superposition, transparent display and the like.

The invention provides a carbonate rock fracture-cave structure seismic characterization method based on deep learning, which overcomes the limitations of manual interpretation and conventional attribute methods, fully extracts effective information in three-dimensional seismic data, really realizes three-dimensional air break, seam and cave identification, and can effectively improve the accuracy, reliability and working efficiency of fracture-control karst fracture-cave structure seismic characterization.

Drawings

In order to more clearly illustrate the embodiments or effects of the invention, the description of the drawings required is provided in the present specification, and the description below is made with reference to the drawings used:

FIG. 1 is a schematic flow chart of a carbonate rock fracture-cave structure seismic characterization method based on deep learning according to the description;

FIG. 2 is a schematic diagram of the internal structure visualization of a three-dimensional codec deep learning framework for fracture seismic recognition in one embodiment provided by the present specification;

FIG. 3 is a block diagram of a fracture hole characterized using a conventional identification method in one embodiment provided in the present specification;

FIG. 4 is a schematic diagram of a fracture-cavity structure characterized by the method of the present invention in one embodiment provided in the present specification;

FIG. 5 is a schematic cross-sectional view of a fracture-fractured-cavity structure characterized by the method of the invention verified by actual drilling in one embodiment provided in the specification.

Detailed Description

The method comprises the steps of analyzing the characteristics of the fracture-control karst fracture and cave body and the characteristics of seismic data, identifying the fracture, the seam and the cave in types, improving the identification precision of the fracture, the seam and the cave by utilizing a deep learning method, and finally realizing the seismic characterization of the fracture and cave structure by a fusion display method. In order to better illustrate the technical solution of the present invention, the following embodiment of the present invention for characterizing the structure of the fractured fissured cave of the aodoite series carbonate rock in a certain block of the Tarim basin is utilized in conjunction with the accompanying drawings to explain the specific implementation mode of the present invention in detail, and the embodiment does not limit the present invention.

Fig. 1 is a schematic flow chart of a deep learning-based carbonate rock fracture-cave structure seismic characterization method described in the present specification, and a detailed description of specific implementation steps is given below.

Step 1, training data set construction. And (3) taking the geological and seismic data characteristics of the actual research area of the Ordovician carbonate rock in the Tarim basin into consideration, and classifying and constructing a fracture, seam and hole training data set by adopting a method of combining actual data and simulation data. The geological feature analysis of the research area mainly analyzes and summarizes the characteristics of the structure, filling property, physical property, elastic parameter and the like of main storage spaces such as fracture, crack, karst cave and the like of the research area. The seismic data analysis mainly analyzes the characteristics of the seismic data, such as main frequency, frequency band, signal-to-noise ratio and the like. Aiming at the difference characteristics of the fracture, the seam and the hole, a training data set is constructed by respectively adopting actual data or numerical simulation data.

Step 1.1, a three-dimensional simulated fracture and forward modeling seismic data set is constructed. Large-scale fractures appear as a dislocation of the in-phase axis in three-dimensional seismic data and can be manually explained, but the difficulty of explanation is large in a two-dimensional section or a horizontal slice. The three-dimensional simulated fracture is to simulate fractures with different dip angles, tendencies, fracture distances and combinations in a three-dimensional space, simultaneously superpose stratums with different structural fluctuation characteristics, and on the basis, three-dimensional convolution is adopted to superpose random noise to generate fracture forward simulation three-dimensional seismic data, wherein the superposed noise needs to consider the noise characteristics of actual seismic data so as to obtain a better actual seismic recognition effect.

And 1.2, constructing a three-dimensional simulated karst cave and forward seismic data set. The karst cave appears as a beaded reflection in the three-dimensional seismic data, which is especially typical of deep Ordovician in the Tarim basin. The three-dimensional simulated karst cave comprises ellipsoidal karst caves with different cave lengths, cave heights and aspect ratios, the distribution of the karst caves is generated by a random simulation method based on a target, stratums with different structural fluctuation change characteristics are overlapped, the physical attributes of the karst cave and surrounding rock are randomly simulated by a sequential Gaussian method, the karst cave and the surrounding rock with different filling characteristics are simulated, on the basis, the actual seismic data are adopted to extract wavelets to perform three-dimensional convolution operation, and random noise is overlapped to generate the karst cave forward simulation three-dimensional seismic data. For fracture and karst cave simulation data, the resolution of actual seismic data of a research area is considered, the grid of the three-dimensional data in the x, y and z directions is set to be 25m 10m, the computational capability limit of a computer is considered, the shape sampling of the three-dimensional data sample is 64 m 64, and more than 100 groups of training samples are generated to be used as a training data set of a subsequent deep learning model.

And 1.3, constructing a logging interpretation crack and a three-dimensional seismic data set beside a well. Due to the fact that the crack size is small, the seismic response characteristics are unclear, and effective data are difficult to generate through a numerical simulation method. The well logging interpretation cracks mainly refer to crack line density, crack porosity and the like of imaging well logging interpretation, the data of a vertical well or a horizontal well is used as tag data as much as possible, and when the imaging well logging data are less, the conventional well logging can be used in a matched mode to identify the crack data; practical three-dimensional seismic data corresponding to the well sides are extracted and used as input data, the number of seismic channels and the length of a vertical time window at the well sides can be optimized through experiments, and meanwhile, seismic attributes related to various cracks can be extracted and used as multi-channel input data.

And 2, establishing and training the earthquake recognition deep learning models of the fracture, the seam and the hole in a classified manner.

And 2.1, establishing and training a fracture recognition model. And (3) fracture identification is used as a three-dimensional image segmentation problem, three-dimensional forward seismic data is used as input, three-dimensional simulation fracture data is used as a label, and a fracture identification three-dimensional convolution codec deep learning framework is built. FIG. 2 shows the internal structure of a three-dimensional codec deep learning framework for seismic recognition of a fracture in a research area, the three-dimensional convolutional codec being composed of an Encoder (Encoder) and a Decoder (Decode), the Encoder being composed of a plurality of three-dimensional convolutional layers, the dimensionality of an output feature volume being continuously reduced by controlling the convolutional step length; the decoder is composed of a plurality of three-dimensional deconvolution layers and convolution layers, the dimensionality of an output characteristic body is continuously increased by controlling the deconvolution step length, and the dimensionality of output data is the same as that of input data. The model output obtains both fracture and non-fracture probability volumes using a linear rectification function (ReLU) as the activation function for the inner convolution layer and a softmax function as the output layer function. A Dropout layer is added after the convolution layer to improve the generalization performance of the model, binary cross entropy (binary cross-entropy) is used as a loss function, Adam is used as an optimization function, and the initial learning rate is set to be 0.001. And respectively taking 70%, 20% and 10% of the fracture data set as a training set, a verification set and a test set, wherein the training set is used for updating model parameters, the verification set is used for supervising the training process, the test set is used for final test of the trained model, the three-dimensional convolutional coder-decoder is repeatedly trained and tested, and the model parameters are continuously adjusted and optimized.

And 2.2, establishing and training a karst cave identification model. And (3) taking the karst cave identification as a three-dimensional image segmentation problem, taking three-dimensional forward seismic data as input, taking three-dimensional simulated karst cave data as a label, and constructing a deep learning framework of the karst cave identification three-dimensional convolutional coder-decoder. The three-dimensional codec model for karst cave identification and the training process are similar to fracture identification, and are not described herein again.

And 2.3, establishing and training a crack identification model. And (3) taking crack identification as a regression fitting problem, taking well-side seismic data as input, taking well logging identification crack data corresponding to the seismic data as a label, and constructing a crack identification three-dimensional convolution network deep learning framework. Compared with a fracture and karst cave identification model, the fracture identification model is relatively simple, the three-dimensional convolution network is composed of a plurality of layers of three-dimensional convolution layers and full-connection layers, input data are small three-dimensional seismic units, and output data are one-dimensional fracture density data. Again, a linear rectification function (ReLU) is used as the activation function, a Dropout layer is added after the convolutional layer, a mean squared error (mean squared error) is used as the loss function, and Adam is used as the optimization function.

And step 3: and (5) classifying and predicting the fracture, seam and hole models. And applying the trained fracture, joint and hole deep learning model to the three-dimensional seismic data of the actual research area to obtain a fracture, joint and hole classification prediction three-dimensional data volume. The shape of an input data sample of the fracture-cavity model is often far smaller than that of actual seismic data, and the prediction of the whole three-dimensional seismic data is gradually completed by adopting a method of respectively sliding in the x direction, the y direction and the z direction.

And 4, step 4: and (5) carrying out structural fusion characterization on the fracture and cavity. The earthquake classification prediction results of the fracture, the seam and the hole are fused by adopting methods such as data merging operation, hollow superposition, transparent display and the like, and the fracture, seam and hole prediction results can be represented in a plane, a section and a three-dimensional space. Through the hollow superposition of prediction results, FIG. 3 is a structural diagram of a fracture-cavity represented by a conventional identification method, and FIG. 4 is a structural diagram of a fracture-cavity represented by the method of the invention. FIG. 5 is a schematic sectional view of a fracture-cavity structure characterized by the method of the invention verified by a real well drilling W1 well, and the well drilling coincidence rate is greatly improved by verifying the seismic characterization result of the fracture-cavity structure in a research area through a plurality of real well drilling.