阅读说明：本技术 一种快速确定辫流带及内部微相组合关系的方法 (Method for rapidly determining braid flow zone and internal microphase combination relationship ) 是由 李晓慧 苏玉亮 王文东 徐纪龙 陈子强 于 2020-06-28 设计创作，主要内容包括：本发明公开一种快速确定辫流带及内部微相组合关系的方法,该方法一是通过野外露头资料对水道及心滩等微相在垂直剖面上的岩性、成分、粒度、韵律性等进行描述,应用Google Earth软件描述不同微相在平面上的形态、规模及组合关系,体现了将今论古的地质思维理念,为精确识别辫流带内微相奠定基础；二是利用可靠的取心井资料,作为神经网络分析的输入数据,对与沉积微相相关的测井参数进行定量分析,提高了定量标准的准确度；三是利用充填颜色及曲线形态的平面分布特征,快速实现了大面积工区辫流带及内部微相的刻画。本发明将现代沉积、野外露头的结果用于指导心滩坝的形态刻画,具有准确、快速、实用等优点,可为同类型致密低渗气田的有效开发提供指导。(The invention discloses a method for rapidly determining a plait drainage strip and an internal microfacies combination relation, which comprises the steps of describing lithology, components, granularity, rhythmicity and the like of microfacies such as a water channel, a cardiac beach and the like on a vertical section through field outcrop data, describing forms, scales and combination relations of different microfacies on a plane by using Google Earth software, reflecting the ancient geological thinking concept of the modern times and laying a foundation for accurately identifying the microfacies in the plait drainage strip; secondly, reliable coring well data are used as input data of neural network analysis to carry out quantitative analysis on logging parameters related to depositional microfacies, so that the accuracy of quantitative standards is improved; thirdly, the drawing of the flow braid zone and the internal micro-phase in a large area work area is quickly realized by utilizing the filling color and the plane distribution characteristics of the curve form. The method uses the results of modern sedimentation and field outcrop to guide the shape portrayal of the cardiac beach dam, has the advantages of accuracy, rapidness, practicability and the like, and can provide guidance for the effective development of the same type of compact low-permeability gas field.)

1. A method for rapidly determining the combination relationship between a braid flow zone and internal micro-phases is characterized by comprising the following steps:

(1) carrying out vertical stage division on the small layer of a single well in a research area, and realizing the closing of a single-stage stratum framework in the area through the stratum division and comparison of points, lines and surfaces;

wherein, the small layer is a stratum unit lower than the section, the lithology, the composition and the biological combination of the small layer have the same characteristics and can be formed by a plurality of deposition cycles; the single-stage stratum refers to the smallest rock stratum unit and is formed by single deposition cycle in the vertical direction;

establishing a 4-level configuration interface with the precision reaching the theoretical research of the Miall reservoir configuration, and then taking single-phase sand bodies with time units and the like as research objects;

(2) establishing a corresponding relation between the logging phase and the core of different sedimentary microfacies, and determining logging parameters most relevant to the sedimentary microfacies, namely the numerical value and the form of a GR curve are most relevant to the sedimentary microfacies;

taking a single-stage stratum as a unit, carrying out manual interpretation of sedimentary microfacies according to the logging curve form of a core well section and core data, and identifying three microfacies types of a flooding plain, a cardiac beach and a water channel filling;

(3) establishing GR quantitative standards for various microphase identifications by observing natural gamma GR characteristics of different microphases of the core well by utilizing a neural network analysis technology;

firstly, establishing a characteristic vector of neural network analysis, wherein a sample is derived from the manual interpretation of a core phase and a logging phase of a core well, the characteristic parameter of a logging curve segment corresponding to each micro-phase segment forms a characteristic vector, and the characteristic vector consists of logging parameters GR, AC and LLD and is input data for training processing of a neural network; then carrying out cluster analysis on the characteristic vectors, establishing a neural network model, obtaining the logging parameter identification range of various microfacies, and identifying 7 GR typical curve forms and quantitative standards of the cardiac beach, the braided water channel and the flooding plain;

color fill GR typical curve with size of GR value, near red for cardiac beach, 30< GR < 50; near yellow indicates braided watercourses, 50< GR < 80; the color of the water channel is near green, which indicates that the water channel is filled with muddy substances or floods plain, and GR is more than 80;

(4) analyzing the control effect of the water channel on the shape of the cardiac beach by using modern sedimentary and field outcrop investigation data;

firstly, determining field outcrop and modern sedimentary data which have good similarity with a sedimentary system, environment and sand type of a research area, then describing lithology, composition, granularity and rhythmicity of water channels and cardiac beach microfacies on a vertical section through the field outcrop and the modern sedimentary data, identifying and extracting geological information of different rivers and different time by applying Google Earth software, researching restraint of braided water channels on the form of the cardiac beach dam, and describing form, scale and combination relation of different microfacies on a plane;

(5) projecting a GR curve with filling colors onto a plane by taking any single-phase stratum as a research object, and identifying the boundaries of the braid flow zones which are communicated in a large area along the ancient flowing water direction by utilizing the sedimentary microphase standards established in the step (2) and the step (3);

if the plane presents a large area of green color, GR is greater than 80, generally represents the flooding plain deposition of thicker mudstone, and is an important mark for determining the boundaries of the braid flow zones;

if a large area of cardiac beach phase is near red, 30< GR <50, and 50< GR <80, the area can be judged as the main body part of the braid flow zone.

2. The method for rapidly determining the association between a shunt strip and an internal micro-phase according to claim 1, further comprising the steps of:

(6) determining the extension path of each water channel by taking the planar distribution of GR curves as constraint in the flow splitting belt, and realizing the planar combination of the water channel and the cardiac beach dam by utilizing the constraint of the water channel on the form of the cardiac beach dam established in the step (4);

firstly, identifying a braided water channel:

in the single-stage braided flow zone, carrying out deterministic braided water channel extension direction identification by utilizing well connecting section and GR curve plane spreading interaction analysis;

if the medium-height section of the river channel zone sand corresponding to the adjacent well is a thick-layer mudstone section, the shuttle of the braided water channel between the two wells can be judged;

if the two wells have obvious grain sequence gyrus difference, the shuttling of the braided water channel between the two wells can be judged;

if the sandstone section is obviously thinner than the adjacent well, the shuttle of the braided water channel between the two wells can be judged;

if the GR curve of the single well is in a single bell shape, the well obviously grows and becomes thin upwards, deposition and turns back, and the well can be judged to be positioned at the filling and deposition part of the river channel and a braided water channel passes through the well;

then judging the combination relationship of the water channel and the cardiac flat dam plane:

if the braided water channel surrounding the cardiac beach is identified to be symmetrical, the cardiac beach dam is subjected to the effects of downstream accumulation and vertical accumulation, and the form of the cardiac beach dam is judged to be a longitudinal sand dam;

if the braided water channel surrounding the heart beach is identified to be asymmetric water flow, the heart beach dam is subjected to lateral accumulation, and the heart beach dam is judged to be an inclined sand dam;

if the recognized braided water channels on the two sides of the middle lower part of the cardiac beach dam are asymmetric water flows, one side of the cardiac beach dam is eroded, the other side of the cardiac beach dam is deposited, and the cardiac beach dam is judged to be in a lateral migration form;

if the range of the nearly red cardiac beach development area is large, sediment is judged to be unloaded at the tail part of the cardiac beach dam to form dam tail sediment, the dam tail is continuously prolonged, and finally, braided water channels between the cardiac beach dams are filled to form the composite cardiac beach dam.

Technical Field

The invention relates to the field of oil reservoir description, in particular to a method for quickly determining a braided flow zone and internal microphase combination relationship.

Background

The braided river flow phase generally has the characteristics of high migration rate, sand body model communication, uneven distribution of gas-containing reservoirs and the like, so that quantitative description is difficult, and finely depicting the form and scale of braided water channels and the heart beach dams becomes a key point of braided river configuration research. Although the thinking of 'hierarchical analysis', 'mode fitting' and 'multidimensional interaction' sand body dissection is formed, the method is still in the qualitative to semi-quantitative mode exploration stage, and a braided water channel and cardiac beach bar scale quantitative determination method with common meaning does not exist.

The braided river has various deposition types, complex reservoir structure and numerous controlled factors, a uniform microfacies identification method which is suitable for different gas reservoir types is not formed, and the test and the development of a mine field cannot be effectively guided. At present, some means are to adopt deposition microphase explanation to a single well, and the work is more complicated.

Disclosure of Invention

Based on the technical problems, the invention provides a method for rapidly determining the combination relationship between the braid flow zone and the internal microfacies, which takes a plane as a research unit, avoids the complex work of sedimentary microfacies explanation on a single well, can rapidly realize sedimentary microfacies portrayal of a large-area work area, and provides a feasible operation method for accurately determining the plane distribution position of the sand body of the cardiac beach dam.

The technical solution adopted by the invention is as follows:

a method for rapidly determining the combination relationship between a braid flow zone and internal micro-phases comprises the following steps:

(1) carrying out vertical stage division on the small layer of a single well in a research area, and realizing the closing of a single-stage stratum framework in the area through the stratum division and comparison of points, lines and surfaces;

wherein, the small layer is a stratum unit lower than the section, the lithology, the composition and the biological combination of the small layer have the same characteristics and can be formed by a plurality of deposition cycles; the single-stage stratum refers to the smallest rock stratum unit and is formed by single deposition cycle in the vertical direction;

establishing a 4-level configuration interface with the precision reaching the theoretical research of the Miall reservoir configuration, and then taking single-phase sand bodies with time units and the like as research objects;

(2) establishing a corresponding relation between the logging phase and the core of different sedimentary microfacies, and determining logging parameters most relevant to the sedimentary microfacies, namely the numerical value and the form of a GR curve are most relevant to the sedimentary microfacies;

taking a single-stage stratum as a unit, carrying out manual interpretation of sedimentary microfacies according to the logging curve form of a core well section and core data, and identifying three microfacies types of a flooding plain, a cardiac beach and a water channel filling;

(3) establishing GR quantitative standards for various microphase identifications by observing natural gamma GR characteristics of different microphases of the core well by utilizing a neural network analysis technology;

firstly, establishing a characteristic vector of neural network analysis, wherein a sample is derived from the manual interpretation of a core phase and a logging phase of a core well, the characteristic parameter of a logging curve segment corresponding to each micro-phase segment forms a characteristic vector, and the characteristic vector consists of logging parameters GR, AC and LLD and is input data for training processing of a neural network; then carrying out cluster analysis on the characteristic vectors, establishing a neural network model, obtaining the logging parameter identification range of various microfacies, and identifying 7 GR typical curve forms and quantitative standards of the cardiac beach, the braided water channel and the flooding plain;

color fill GR typical curve with size of GR value, near red for cardiac beach, 30< GR < 50; near yellow indicates braided watercourses, 50< GR < 80; the color of the water channel is near green, which indicates that the water channel is filled with muddy substances or floods plain, and GR is more than 80;

(4) analyzing the control effect of the water channel on the shape of the cardiac beach by using modern sedimentary and field outcrop investigation data;

firstly, determining field outcrop and modern sedimentary data which have good similarity with a sedimentary system, environment and sand type of a research area, then describing lithology, composition, granularity and rhythmicity of water channels and cardiac beach microfacies on a vertical section through the field outcrop and the modern sedimentary data, identifying and extracting geological information of different rivers and different time by applying Google Earth software, researching restraint of braided water channels on the form of the cardiac beach dam, and describing form, scale and combination relation of different microfacies on a plane;

(5) projecting a GR curve with filling colors onto a plane by taking any single-phase stratum as a research object, and identifying the boundaries of the braid flow zones which are communicated in a large area along the ancient flowing water direction by utilizing the sedimentary microphase standards established in the step (2) and the step (3);

if the plane presents a large area of green color, GR is greater than 80, generally represents the flooding plain deposition of thicker mudstone, and is an important mark for determining the boundaries of the braid flow zones;

if a large area of cardiac beach phase is near red, 30< GR <50, and 50< GR <80, the area can be judged as the main body part of the braid flow zone.

The above method further comprises the steps of:

(6) determining the extension path of each water channel by taking the planar distribution of GR curves as constraint in the flow splitting belt, and realizing the planar combination of the water channel and the cardiac beach dam by utilizing the constraint of the water channel on the form of the cardiac beach dam established in the step (4);

firstly, identifying a braided water channel:

in the single-stage braided flow zone, carrying out deterministic braided water channel extension direction identification by utilizing well connecting section and GR curve plane spreading interaction analysis;

if the medium-height section of the river channel zone sand corresponding to the adjacent well is a thick-layer mudstone section, the shuttle of the braided water channel between the two wells can be judged;

if the two wells have obvious grain sequence gyrus difference, the shuttling of the braided water channel between the two wells can be judged;

if the sandstone section is obviously thinner than the adjacent well, the shuttle of the braided water channel between the two wells can be judged;

if the GR curve of the single well is in a single bell shape, the well obviously grows and becomes thin upwards, deposition and turns back, and the well can be judged to be positioned at the filling and deposition part of the river channel and a braided water channel passes through the well;

then judging the combination relationship of the water channel and the cardiac flat dam plane:

if the braided water channel surrounding the cardiac beach is identified to be symmetrical, the cardiac beach dam is subjected to the effects of downstream accumulation and vertical accumulation, and the form of the cardiac beach dam is judged to be a longitudinal sand dam;

if the braided water channel surrounding the heart beach is identified to be asymmetric water flow, the heart beach dam is subjected to lateral accumulation, and the heart beach dam is judged to be an inclined sand dam;

if the recognized braided water channels on the two sides of the middle lower part of the cardiac beach dam are asymmetric water flows, one side of the cardiac beach dam is eroded, the other side of the cardiac beach dam is deposited, and the cardiac beach dam is judged to be in a lateral migration form;

if the range of the nearly red cardiac beach development area is large, sediment is judged to be unloaded at the tail part of the cardiac beach dam to form dam tail sediment, the dam tail is continuously prolonged, and finally, braided water channels between the cardiac beach dams are filled to form the composite cardiac beach dam.

The beneficial technical effects of the invention are as follows:

the method for rapidly determining the combination relationship of the braid flow zone and the internal microfacies, provided by the invention, has the advantages that lithology, components, granularity, rhythmicity and the like of the microfacies such as a water channel, a cardiac beach and the like on a vertical section are described through field outcrop data, and the shape, the scale and the combination relationship of different microfacies on a plane are described by using Google Earth software, so that the geological thinking concept of ancient theory at present is embodied, and a foundation is laid for accurately identifying the microfacies in the braid flow zone; secondly, reliable coring well data are used as input data of neural network analysis to carry out quantitative analysis on logging parameters related to depositional microfacies, so that the accuracy of quantitative standards is improved; thirdly, the drawing of the flow braid zone and the internal micro-phase in a large area work area is quickly realized by utilizing the filling color and the plane distribution characteristics of the curve form.

The method is practical and reliable, can accurately determine the plane distribution position of the sand body of the dominant cardiac beach, quickly realizes the deposition microphase carving of a large-area work area, definitely facilitates the distribution characteristics of a reservoir stratum, and provides guidance for the effective development of the same type of compact low-permeability gas field at home and abroad.

Drawings

The invention will be further described with reference to the following detailed description and drawings:

FIG. 1 is a diagram showing the relationship between a logging phase and a core of a core;

FIG. 2 is a schematic diagram of controlling and reforming the morphology of a beach dam with a braided waterway.

Detailed Description

The invention provides a method for rapidly determining the combination relation of a braid flow zone and internal microfacies, which takes a plane as a research unit, avoids the complex work of sedimentary microfacies explanation on a single well, can rapidly realize sedimentary microfacies portrayal of a large-area work area, and provides a feasible operation method for accurately determining the plane distribution position of sand bodies of a beach dam. The method comprises the following steps:

(1) carrying out vertical stage division on small layers of a single well in a research area, and realizing the closing of a single-stage stratum framework in the area through the stratum division and comparison of points, lines and surfaces (single well, connected wells and multiple wells); wherein, the small layer refers to a stratum unit lower than the section, the lithology, the composition, the biological combination and the like of the small layer have the same characteristics and can be formed by a plurality of deposition cycles; the single-stage formation refers to the smallest unit of rock formation, consisting of a single depositional cycle in the vertical direction. Establishing a 4-level configuration interface with the precision reaching the Miall reservoir configuration theoretical research, and then taking single-phase sand bodies with time units and the like as research objects.

(2) Establishing a corresponding relation between the logging phase and the core of different sedimentary microfacies, determining logging parameters most relevant to the sedimentary microfacies as shown in figure 1, and obtaining the numerical value and the form of a GR curve most relevant to the sedimentary microfacies; and (3) carrying out manual interpretation of sedimentary microfacies according to the logging curve form and core data of the core well section by taking a single-stage stratum as a unit, and identifying three microfacies types of flooding plain, cardiac beach and water channel filling.

(3) And establishing GR quantitative standards for various microphase identifications by observing natural gamma GR characteristics of different microphases of the core well by utilizing a neural network analysis technology. Firstly, establishing a characteristic vector of neural network analysis, wherein a sample is derived from the manual interpretation of a core phase and a logging phase of a core well, the characteristic parameter of a logging curve segment corresponding to each micro-phase segment forms a characteristic vector, and the characteristic vector consists of logging parameters GR, AC and LLD and is input data for training processing of a neural network; then, carrying out cluster analysis on the characteristic vectors, establishing a neural network model, and obtaining the logging parameter identification ranges of various microfacies; 7 GR typical curve forms and quantitative standards of a cardiac beach, a braided waterway and a flooding plain are identified, the GR typical curve is subjected to color filling by using the GR value, the color is near red (30< GR <50) represents the cardiac beach, the color is near yellow (50< GR <80) represents the braided waterway, and the color is near green (GR >80) represents the muddy filling or flooding plain of the waterway.

(4) Analyzing the control effect of the water channel on the shape of the cardiac beach by using modern sedimentary and field outcrop investigation data; firstly, determining field outcrop and modern sedimentary data which have good similarity with sedimentary systems, environments and sand body types in a research area, then describing lithology, components, granularity, rhythmicity and the like of micro-facies such as a water channel and a heart beach on a vertical section through the field outcrop data, recognizing and extracting geological information of different rivers and different time by applying the advantages of all-around, high-resolution and continuous observation of Google Earth software, researching restraint of a braided water channel on the form of the heart beach dam, and describing form, scale and combination relation of different micro-facies on a plane, as shown in figure 2.

(5) And (3) projecting the GR curve with the filling color onto a plane by taking any single-phase stratum as a research object, and identifying the boundaries of the large-area communicated braid flow zones along the ancient flowing water direction by utilizing the sedimentary microphase standards established in the step (2) and the step (3).

If a large area of near green color is presented on a plane (GR >80), the general representation of the flooded plain deposition of thicker mudstone is an important mark for determining the boundaries of the braid flow zone.

If a large area of cardiac beach phase with red color (30< GR <50) and braided channel phase with yellow color (50< GR <80) are presented on the plane, the area can be judged as the main body part of the braided flow band.

(6) And (4) determining the extension path of each water channel by taking the planar distribution of GR curves as constraint in the flow diversion strips, and realizing the planar combination of the water channel and the cardiac beach dam by utilizing the constraint of the water channel on the form of the cardiac beach dam established in the step (4).

Firstly, identifying a braided water channel:

and in the single-stage braided flow zone, carrying out deterministic braided water channel extension direction identification by utilizing the well connecting section and GR curve plane spreading interaction analysis.

If the medium-height section of the river channel zone sand corresponding to the adjacent well is a thick-layer mudstone section, the shuttle of the braided water channel between the two wells can be judged;

if the two wells have obvious difference of particle order gyre, if one well is an upward uniform prosodic sequence and the adjacent well is a single upward thinning sequence, the shuttle of the braided water channel between the two wells can be judged;

if the sandstone section is obviously thinner than the adjacent well, the shuttle of the braided water channel between the two wells can be judged.

If the GR curve of the single well is in a single bell shape and grows obviously, the well becomes thin upwards and deposition circles, and the well can be judged to be positioned at the filling deposition part of the river channel and be penetrated by a braided water channel.

Then judging the combination relationship of the water channel and the cardiac flat dam plane:

if the braided water channel surrounding the cardiac beach is identified to be symmetrical, the cardiac beach dam is subjected to the effects of downstream accumulation and vertical accumulation, and the form of the cardiac beach dam is judged to be a longitudinal sand dam;

if the braided water channel surrounding the heart beach is identified to be asymmetric water flow, the heart beach dam is subjected to lateral accumulation, and the heart beach dam is judged to be an inclined sand dam;

if the recognized braided water channels on the two sides of the middle lower part of the cardiac beach dam are asymmetric water flows, one side of the cardiac beach dam is eroded, the other side of the cardiac beach dam is deposited, and the cardiac beach dam is judged to be in a lateral migration form;

if the range of the nearly red cardiac beach development area is large, sediment is judged to be unloaded at the tail part of the cardiac beach dam to form dam tail sediment, the dam tail is continuously prolonged, and finally, braided water channels between the cardiac beach dams are filled to form the composite cardiac beach dam.

The method uses the modern sedimentary and field outcrop results to guide the morphological portrayal of the heart beach dam, embodies the geological thinking method of the modern times, can accurately determine the plane distribution position of the dominant heart beach sand body, quickly realizes sedimentary microfacies portrayal of a large-area work area, clearly facilitates the distribution characteristics of a reservoir stratum, and provides guidance for the effective development of the same type of compact hypotonic gas fields at home and abroad.

Parts not described in the above modes can be realized by adopting or referring to the prior art.

It is to be understood that the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art may make modifications, alterations, additions or substitutions within the spirit and scope of the present invention.