CN112528106B

CN112528106B - Volcanic lithology recognition method

Info

Publication number: CN112528106B
Application number: CN201911330967.5A
Authority: CN
Inventors: 仇鹏; 李道清; 王彬; 苏航; 闫利恒; 陈超; 戴灿星; 王泉
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2019-12-20
Filing date: 2019-12-20
Publication date: 2024-06-25
Anticipated expiration: 2039-12-20
Also published as: CN112528106A

Abstract

The invention provides a volcanic lithology recognition method. The volcanic lithology recognition method comprises the following steps: step S10: collecting conventional logging information of volcanic rocks in a target area, and establishing a standardized database based on the conventional logging information; step S20: selecting a plurality of logging curves sensitive to volcanic lithology from a standardized database; step S30: based on a plurality of logging curves, logging curve intersection plates capable of identifying different volcanic lithologies are drawn, the volcanic lithologies are divided, and the distribution range of volcanic clastic rock and/or volcanic lava is determined. The technical scheme of the invention provides a method for efficiently and accurately identifying the lithology of volcanic rock by utilizing the ideas of conventional logging data and classification, and has higher popularization adaptability.

Description

Volcanic lithology recognition method

Technical Field

The invention relates to the technical field of oil and gas exploration and development, in particular to a volcanic lithology recognition method.

Background

The correct identification of volcanic lithology is an important means for reasonably knowing reservoirs and comprehensively evaluating geological features, and has important significance for scientifically developing volcanic facies, volcanic reservoir prediction research and guiding oil and gas exploration, evaluation and development deployment. The problem of great difficulty in identifying volcanic lithology based on conventional logging scales has been a worldwide problem for the past years. The former people also do a great deal of exploration innovation in the aspect of volcanic lithology recognition, such as:

1) A method and a device for identifying lithology of a changed volcanic rock (patent number: CN102053268 a) proposes a method and apparatus for carrying out volcanic lithology recognition using drilling, logging and chemical analysis data correlation. The method has the advantages of clear flow, strong operability, high experience requirements and difficult popularization, and the difficulty of extracting drilling, recording and logging characteristic parameters and fusing information.

2) Method and device for determining effective reservoir of altered volcanic rock in oil and gas exploration (patent number: CN103616731 a) proposes a method and principle for determining the effective reservoir of the altered volcanic rock established by rock alteration factors and reservoir quality factors, which has the difficulty of calculating the alteration factors of the rock (i.e. identifying whether the volcanic rock is altered). The method is simple in process and easy to operate, is limited to identification of the changed volcanic rock, and requires full-diameter rock core calibration to determine whether the rock core is an effective reservoir or not, so that the cost is relatively high.

3) A three-dimensional volcanic lithology recognition method (patent number is CN 102071928A) provides a method for realizing three-dimensional volcanic lithology recognition by using a support vector machine based on element capture logging, imaging logging data and structural information of rock. The effect is good, but the cost is expensive and the popularization is poor.

4) A lithology recognition method of a carboloy volcanic oil reservoir (patent number is CN 104929626A) provides a lithology recognition method based on rock debris, a logging intersection map, lithology division and sheet naming. The method has strong operability and reliable results, but has complicated flow, time consumption and large workload.

5) A volcanic lithology recognition method based on electric imaging logging fractal dimension (patent number is CN 108830140A) provides a lithology recognition method based on coring and non-coring well section imaging logging data and calculating the fractal dimension. The precision is relatively reliable, but the method has the advantages of large limitation, high cost, high technical requirements on operators and low popularization.

The mature and effective underground volcanic lithology recognition method mainly depends on the means of element capture energy spectrum, chemical measurement (silicon-alkali method), imaging logging, drilling coring and the like, but for deep, large well spacing and quick phase change areas, the underground volcanic lithology recognition method based on the means has the problems of high cost and great popularization difficulty, and a set of intersection plate and recognition method which are reasonable in structure, economical, efficient, clear in level and accurate in recognition are not formed based on conventional logging data so far. Therefore, on the basis of the knowledge before absorption, the calibration of the core outcrop sample, the induction of imaging logging features and the summary of conventional logging features, a method for identifying the lithology of the volcanic rock is required to be provided with low cost, high efficiency and high popularization applicability.

Disclosure of Invention

The invention mainly aims to provide the volcanic lithology recognition method, which can efficiently and accurately recognize the volcanic lithology by utilizing conventional logging data and has higher popularization adaptability.

In order to achieve the above object, the present invention provides a volcanic lithology recognition method, which includes: step S10: collecting conventional logging information of volcanic rocks in a target area, and establishing a standardized database based on the conventional logging information; step S20: selecting a plurality of logging curves sensitive to volcanic lithology from a standardized database; step S30: based on a plurality of logging curves, logging curve intersection plates capable of identifying different volcanic lithologies are drawn, the volcanic lithologies are divided, and the distribution range of volcanic clastic rock and/or volcanic lava is determined.

Further, when the volcanic lithology is volcanic clastic rock, after step S30, the volcanic lithology recognition method further includes: step S40: selecting a plurality of well logs sensitive to lithology of the pyroclastic rock from a standardized database; step S50: and drawing a logging curve intersection plate capable of identifying different volcaniclastic lithologies, and dividing the volcaniclastic lithologies to obtain a volcaniclastic rock class.

Further, after step S50, the volcanic lithology recognition method further includes: step S60: selecting a plurality of log curves sensitive to lithology of a large class of volcaniclastic rock from a standardized database; step S70: and drawing a logging curve intersection plate capable of identifying lithology of different volcaniclastic rock major categories, and classifying each lithology of the volcaniclastic rock major categories.

Further, a log intersection panel capable of identifying different volcaniclastic lithologies is a natural gamma-density (GR-DEN) intersection panel.

Further, when the volcanic lithology is volcanic lava, after step S30, the volcanic lithology recognition method further includes: step S45: selecting a plurality of logging curves sensitive to volcanic lava lithology from a standardized database; step S55: and drawing a logging curve intersection plate capable of identifying different volcanic lava lithologies, and dividing the volcanic lava lithologies to obtain volcanic lava major categories.

Further, after step S55, the volcanic lithology recognition method further includes: step S65: selecting a plurality of logging curves sensitive to lithology of a volcanic lava major class from a standardized database; step S75: and drawing a logging curve intersection plate capable of identifying lithology of different volcanic lava major categories, and classifying each lithology of the volcanic lava major categories.

Further, the log intersection panels capable of identifying different volcanic lava lithologies are intersection panels of natural gamma and undisturbed formation resistivity (GR-RT).

Further, the volcanic lithology recognition method further comprises the following steps: step S05: the lithology of the volcanic rock is named based on data obtained by one or more of open-end exploration, core observation, experimental analysis and sheet identification modes, so that a lithology naming database of the volcanic rock is obtained; and/or, step S15: and establishing a lithology data database of the volcanic rock based on the lithology data of the volcanic rock obtained by the imaging logging and/or the element capturing logging mode.

Further, the volcanic lithology recognition method further comprises the following steps: step S80: and (3) comparing the lithology naming database of the volcanic rock obtained in the step (S05) and/or the lithology data database of the volcanic rock established in the step (S15) with the partitioned lithology of the volcanic rock to judge the accuracy of the volcanic rock lithology recognition method on the lithology recognition of the volcanic rock.

Further, the log intersection panels capable of identifying different volcanic lithology are intersection panels of natural gamma and undisturbed formation resistivity/sonic moveout (GR-RT/AC).

By applying the technical scheme of the invention, the volcanic lithology is identified by drawing the intersection plate of the well-logging curve which is sensitive to the volcanic lithology response based on the conventional well-logging data; the method can be used for quickly identifying the volcanic lithology by establishing the volcanic lithology identification plate at the well section without coring, without special logging and with conventional logging curves, has the advantages of simple operation steps and low cost, eliminates the interference of reservoir structure factors on the volcanic lithology identification, improves the lithology identification accuracy of an effective reservoir, provides a method for quickly, efficiently, accurately identifying complex volcanic lithology with low cost by using conventional logging data, and has higher popularization adaptability.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:

FIG. 1 shows a flow chart of an embodiment of a volcanic lithology recognition method according to the present invention;

FIG. 2 shows a schematic composition of a base database of an embodiment of a volcanic lithology recognition method according to the present invention;

FIG. 3 illustrates a hierarchical classification diagram of volcanic lithology that needs to be identified in a target region according to an embodiment of the volcanic lithology identification method of the present invention;

FIG. 4 illustrates a natural gamma-to-undisturbed formation resistivity/sonic moveout (GR-RT/AC) intersection of volcanic clastic-volcanic lava lithology recognition according to an embodiment of the volcanic lithology recognition method of the present invention;

FIG. 5 illustrates a natural gamma-to-density (GR-DEN) intersection plate of volcanic lithology recognition according to an embodiment of the volcanic lithology recognition method of the present invention;

FIG. 6 illustrates a cross-plot of natural gamma-rays identified by a volcanic lava major class and undisturbed formation resistivity (GR-RT) in accordance with an embodiment of a volcanic lithology identification method of the present invention;

FIG. 7 illustrates a cross-plot of acoustic moveout versus compensated neutron (AC-CNL) for basic volcanic lithology recognition in accordance with an embodiment of the volcanic lithology recognition method of the present invention;

FIG. 8 illustrates a natural gamma-to-density (GR-DEN) intersection plate for neutral volcanic lithology recognition in accordance with an embodiment of the volcanic lithology recognition method of the present invention;

FIG. 9 illustrates a density versus sonic time difference (DEN-AC) intersection plot of acid volcanic lithology recognition in accordance with an embodiment of the volcanic lithology recognition method of the present invention; and

FIG. 10 illustrates a density versus compensation neutron (DEN-CNL) intersection plot of secondary volcanic lithology recognition in accordance with an embodiment of the volcanic lithology recognition method of the present invention.

Detailed Description

It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The application will be described in detail below with reference to the drawings in connection with embodiments.

It is noted that all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs unless otherwise indicated.

In the present invention, unless otherwise indicated, terms of orientation such as "upper, lower, top, bottom" are used generally with respect to the orientation shown in the drawings or with respect to the component itself in the vertical, upright or gravitational direction; also, for ease of understanding and description, "inner and outer" refers to inner and outer relative to the profile of each component itself, but the above-mentioned orientation terms are not intended to limit the present invention.

The volcanic lithology recognition method is a volcanic lithology recognition method based on conventional logging data.

It should be noted that, according to different target areas, the lithology of volcanic rock is different; the embodiment of the invention selects a region of the Xinjiang Pascal basin as a target region, and applies the volcanic lithology recognition method of the invention to the target region, wherein the result is shown in fig. 4 to 10.

As shown in fig. 1 to 4, in an embodiment of the present invention, a volcanic lithology recognition method includes:

Step S10: collecting conventional logging information of volcanic rocks in a target area, and establishing a standardized database based on the conventional logging information;

step S20: selecting a plurality of logging curves sensitive to volcanic lithology from the standardized database;

Step S30: based on the plurality of logging curves, a logging curve intersection plate capable of identifying different volcanic lithologies is drawn, the volcanic lithologies are divided, and the distribution range of volcanic clastic rock and/or volcanic lava is determined.

Specifically, step S10 is to collect, sort and normalize conventional log data collected by different log series, establish a normalized log data database, that is, collect and sort conventional log data collected by different log series in a target area, normalize the conventional log data, and then establish a normalized log data database based on the normalized conventional log data; by carrying out standardized processing on conventional logging data, correction on conventional logging data acquired by different logging series can be realized, thereby being beneficial to eliminating systematic errors and improving accuracy of lithology identification; step S20, selecting a plurality of logging curves with better identification effect, which can identify the lithology of volcanic rock, from the standardized logging data database on the basis of step S10; step S20 utilizes standardized conventional logging data in the standardized logging data database established in step S10 to determine a plurality of logging curves which can identify volcanic lithology and have relatively good identification effect on the volcanic lithology, and lays a foundation for ensuring accurate identification of the volcanic lithology through the logging curves in the subsequent steps; step S30 is to draw a cross plot based on the plurality of logging curves on the basis of step S20, to identify volcanic lithology, to analyze the drawn logging curve cross plot, to divide distribution areas of different volcanic lithology, so as to determine upper and lower limit values of the distribution areas of different volcanic lithology and/or to establish a linear relation of different volcanic lithology.

Further, in step S10, the conventional logging data is logging data obtained by a conventional logging method, where the conventional logging method mainly refers to 9 conventional logging curves applied in the oil and gas exploration field, including natural Gamma (GR), acoustic time difference (AC), density (DEN), compensated Neutron (CNL), natural potential (SP), undisturbed formation Resistivity (RT), invaded zone Resistivity (RI), formation water resistivity (Ro), and borehole diameter (CAL).

It should be noted that, the standardized processing procedure of the conventional logging data is a conventional technical means in the art, and will not be described herein.

It should be noted that, in the embodiment of the present invention, the selection of the logging curve sensitive to the volcanic lithology response is determined by the sensitive parameter sensitive to the volcanic lithology response, and the selection of the sensitive parameter is based on a large number of logging curves and the combination of the logging curves, that is, the intersection of the logging curves is continuously tried to be made, which curve can be accurately distinguished from the volcanic lithology, and the one that can accurately distinguish and determine the volcanic lithology is determined as the logging curve sensitive to the volcanic lithology response.

Specifically, as shown in fig. 4, in the embodiment of the present invention, in step S20, the selected multiple logs sensitive to the lithology response of the volcanic rock are natural Gamma (GR), undisturbed formation Resistivity (RT) and acoustic wave time difference (AC) curves, and on the basis of step S20, the intersection of the logs capable of identifying different lithology of the volcanic rock, which is drawn in step S30, is the intersection of natural gamma and undisturbed formation resistivity/acoustic wave time difference (GR-RT/AC).

As shown in fig. 4, a cross plot of natural gamma and undisturbed formation resistivity/sonic moveout (GR-RT/AC) is created, wherein the abscissa is the natural gamma value in API, the ordinate is the ratio of undisturbed formation resistivity to sonic moveout in (Ω -m)/(μs/ft); analyzing and dividing volcaniclastic rock and volcaniclastic rock lithology distribution areas; respectively determining upper and lower limit values of respective distribution areas, and/or establishing a linear relation according to the need; through the steps, volcanic lithology is divided into volcanic clastic rock and volcanic lava, and the volcanic clastic rock and volcanic lava distribution areas are divided by utilizing the natural gamma and undisturbed stratum resistivity/sonic time difference (GR-RT/AC) intersection plate; upper and lower limits of the respective distribution areas of the volcaniclastic rock and the volcaniclastic rock are determined, and/or respective linear relations of the volcaniclastic rock and the volcaniclastic rock are established according to requirements.

The technical scheme provides a method for identifying volcanic lithology based on conventional logging information, specifically, the volcanic lithology is identified by drawing a cross-plot of a logging curve sensitive to volcanic lithology response based on the conventional logging information; the method can be used for quickly and accurately identifying the complex volcanic lithology by establishing a volcanic lithology identification plate at the well section without coring, without special logging and with a conventional logging curve, has the advantages of simple operation steps and low cost, eliminates the interference of reservoir structure factors on the volcanic lithology identification, improves the lithology identification accuracy of an effective reservoir, and provides a method for quickly, efficiently, accurately identifying the complex volcanic lithology by using conventional logging data, and has higher popularization adaptability.

When the volcanic lithology is determined to be volcanic clastic rock and volcanic lava, there is no sequence in identifying the volcanic clastic rock lithology and the volcanic lava lithology, and the volcanic clastic rock lithology or the volcanic lava lithology can be selected to be identified according to actual conditions and actual requirements.

Preferably, as shown in fig. 1 and 2, in an embodiment of the present invention, when the volcanic lithology is volcaniclastic rock, after step S30, the volcanic lithology recognition method further includes:

step S40: selecting a plurality of well logs sensitive to lithology of the pyroclastic rock from a standardized database;

step S50: and drawing a logging curve intersection plate capable of identifying different volcaniclastic lithologies, and dividing the volcaniclastic lithologies to obtain a volcaniclastic rock class.

Specifically, through step S30, the lithology of the volcanic rock is divided, and the distribution areas of different lithology of the volcanic rock and the upper and lower limit values of the respective distribution areas are determined; when volcanic lithology contains volcanic clastic, determining upper and lower limit values of a distribution area of the volcanic clastic through a step S30, establishing a log intersection plate on the basis of the step S30, and dividing the volcanic clastic lithology to obtain a volcanic clastic class; more specifically, based on step S30, step S40 is to select a plurality of logging curves with better identification effect, which can identify the pyroclastic rock major class, from the standardized logging data database; step S40, determining a plurality of logging curves which can identify the large class of volcaniclastic rock and have relatively good identification effect on the large class of volcaniclastic rock by using standardized conventional logging data in a standardized logging data database, and laying a foundation for ensuring accurate identification of the large class of volcaniclastic rock through the logging curves in the subsequent steps; step S50 is to draw a cross-plot based on the above-mentioned plurality of log curves in combination with the distribution areas of the volcaniclastic rock determined in step S30 on the basis of step S40, to identify the lithology of the volcaniclastic rock, to divide the distribution areas of different lithologies of the volcaniclastic rock, i.e. to divide the distribution areas of the volcaniclastic rock, and to further determine the upper and lower limit values of the respective distribution areas and/or to establish respective linear relations.

In the technical scheme, based on conventional logging data, the lithology of each major class of volcanic is identified by drawing a cross-plot of a logging curve sensitive to lithology response of each major class of volcanic in combination with the distribution area of each major class of volcanic determined in the step S30, and the method is simple in operation steps and low in cost; the invention further provides a thought for classifying and identifying volcanic lithology on the basis of the steps S10 to S30, wherein the volcanic lithology is firstly classified into major categories by drawing a logging curve intersection chart, the distribution range of each major category of volcanic is determined according to the distribution area of each major category of the classified volcanic, on the basis, the logging curve intersection chart of each major category of the volcanic is respectively drawn for each major category of the determined volcanic, and the distribution area of each major category of lithology is classified to determine the distribution range of each major category of lithology so as to realize rapid identification of the lithology of each major category of the volcanic; the thought is reasonable in structure and clear in hierarchy, can quickly, efficiently and accurately identify lithology of various large types of volcanic rocks through the steps, and has higher popularization adaptability.

Specifically, as shown in fig. 5, in the embodiment of the present invention, in step S40, the plurality of log curves sensitive to the lithology response of the pyroclastic rock are selected as natural Gamma (GR) and Density (DEN) curves, and on the basis of step S40, the log curve intersection plate capable of identifying different lithologies of the pyroclastic rock, which is drawn in step S50, is an intersection plate of natural gamma and density (GR-DEN).

As shown in fig. 5, according to the distribution value range (i.e., the distribution area and the distribution range) of the volcaniclastic rock divided in the step S30, an intersection chart of natural gamma and density (GR-DEN) is established, wherein the abscissa is a natural gamma value, the unit is API, and the ordinate is a density value, the unit is g/cm ³; analyzing and dividing areas of volcaniclastic rock large-class distribution; respectively determining upper and lower limit values of a distribution area of a volcaniclastic rock major class, and/or establishing a linear relation according to the requirement; through the steps, the lithology of the volcaniclastic rock is divided into tuff clay rock and tuff sandstone by utilizing the intersection plate of the natural gamma and the density (GR-DEN), and the distribution areas of the tuff clay rock and the tuff sandstone are divided; and determining the upper limit value and the lower limit value of the distribution area of each of the tuff mudstone and the tuff sandstone, and/or establishing a linear relation of each of the tuff mudstone and the tuff sandstone according to the requirement.

According to the technical scheme, based on conventional logging data, the volcaniclastic rock lithology is identified by drawing the intersection chart of the logging curve sensitive to the volcaniclastic rock lithology response in combination with the volcaniclastic rock distribution area determined in the step S30, and the method is simple in operation steps, low in cost and capable of quickly, efficiently and accurately identifying the volcaniclastic rock lithology.

When the pyroclastic rock is classified in step S50, whether a new intersection chart needs to be established or not may be determined according to the distribution value range of the classified pyroclastic rock to further classify the volcanic rock of the next stage of the pyroclastic rock.

Preferably, as shown in fig. 1 to 5, in an embodiment of the present invention, after step S50, the volcanic lithology recognition method further includes:

Step S60: selecting a plurality of log curves sensitive to lithology of a large class of volcaniclastic rock from a standardized database;

Step S70: and drawing a logging curve intersection plate capable of identifying lithology of different volcaniclastic rock major categories, and classifying each lithology of the volcaniclastic rock major categories.

Specifically, through step S50, the lithology of the volcaniclastic rock is divided to obtain the volcaniclastic rock major categories, and the distribution areas of the volcaniclastic rock major categories and the upper and lower limit values of the distribution areas of the volcaniclastic rock major categories are determined; based on the step S50, step S60 is to select a plurality of logging curves with better identification effect, which can identify lithology of each major class of volcaniclastic rock from the standardized logging data database; step S60, determining a plurality of logging curves which can identify lithology of various major categories of volcaniclastic rock and have relatively good identification effect on the lithology of the various major categories of volcaniclastic rock by utilizing conventional logging data in a standardized logging data database, and laying a foundation for ensuring accurate identification of the lithology of the volcaniclastic rock major categories through the logging curves in the subsequent steps; step S70 is to draw intersection plates based on the above-mentioned multiple log curves in combination with the distribution areas of the various major types of volcaniclastic rock determined in step S50 on the basis of step S60, to identify lithology of the various major types of volcaniclastic rock, to divide the distribution areas of lithology of the various major types of volcaniclastic rock by analyzing the drawn intersection plates of the log curves, and to further determine upper and lower limit values of the distribution areas and/or to establish a linear relation.

In the technical scheme, based on conventional logging data, the lithology of each major class of the volcaniclastic rock is identified by drawing a cross plot of a logging curve sensitive to lithology response of each major class of the volcaniclastic rock in combination with the distribution areas of the volcaniclastic rock major classes determined in the step S50, and the method has the advantages of simple operation steps and low cost; based on the step S40 and the step S50, the invention utilizes the thought of classifying and identifying the lithology of the volcanic rock in a grading manner, and the distribution areas of the lithology of each major class of the volcanic rock are rapidly divided by drawing a logging curve intersection plate so as to determine the distribution range of the lithology of each major class of the volcanic rock, thereby realizing rapid identification of the lithology of each major class of the volcanic rock. Through the steps, lithology of various large types of volcaniclastic rock can be rapidly, efficiently and accurately identified, and the method has high popularization adaptability.

The lithology of each major class of volcaniclastic rock is identified in no sequence.

Preferably, as shown in fig. 1 to 4 and 6, in the embodiment of the present invention, when the volcanic lithology is volcanic lava, after step S30, the volcanic lithology recognition method further includes:

Step S45: selecting a plurality of logging curves sensitive to volcanic lava lithology from a standardized database;

Step S55: and drawing a logging curve intersection plate capable of identifying different volcanic lava lithologies, and dividing the volcanic lava lithologies to obtain volcanic lava major categories.

Specifically, through step S30, volcanic lithology is classified into a large class, and distribution areas of different volcanic lithology and upper and lower limit values of the distribution areas are determined; when volcanic lava is contained in the lithology of the volcanic lava, determining upper and lower limit values of a distribution area of the volcanic lava through a step S30, establishing a logging curve intersection chart on the basis of the step S30, and classifying the lithology of the volcanic lava into a large class to obtain the large class of the volcanic lava; more specifically, based on step S30, step S45 is to select a plurality of logging curves with better identification effect, which can identify the volcanic lava major class, from the standardized logging data database; step S45 utilizes standardized conventional logging data in a standardized logging data database to determine a plurality of logging curves which can identify the volcanic lava major class and have relatively good identification effect on the volcanic lava major class, and lays a foundation for ensuring accurate identification of the volcanic lava major class through the logging curves in the subsequent steps; step S55 is to draw intersection panels based on the above-mentioned multiple logging curves in combination with the distribution areas of the lava determined in step S30 on the basis of step S45, to identify lithology of the lava, to analyze the drawn intersection panels of the logging curves, to divide the distribution areas of different lithology of the lava, i.e. to divide the distribution areas of the lava, and upper and lower limits of the distribution areas, and/or to establish respective linear relations.

In the technical scheme, based on conventional logging data, the lithology of each major class of volcanic rock is identified by drawing a cross-plot of a logging curve sensitive to lithology response of each major class of volcanic rock in combination with the distribution areas of each major class of volcanic rock determined in the step S30, and the method has the advantages of simple operation steps and low cost; the invention further provides a thought for classifying and identifying volcanic lithology on the basis of the steps S10 to S30, wherein the volcanic lithology is firstly classified into major categories by drawing a logging curve intersection chart, the distribution range of each major category of volcanic is determined according to the distribution area of each major category of the classified volcanic, on the basis, the logging curve intersection chart of each major category of the volcanic is respectively drawn for each major category of the determined volcanic, and the distribution area of each major category of lithology is classified to determine the distribution range of each major category of lithology so as to realize rapid identification of the lithology of each major category of the volcanic; the thought is reasonable in structure and clear in hierarchy, can quickly, efficiently and accurately identify lithology of various large types of volcanic rocks through the steps, and has higher popularization adaptability.

Specifically, as shown in fig. 6, in the embodiment of the present invention, in step S45, the selected multiple logs sensitive to the volcanic lava lithology response are natural Gamma (GR) and undisturbed formation Resistivity (RT), and on the basis of step S45, the intersection of the logs capable of identifying different volcanic lava lithology, which is drawn in step S55, is the intersection of natural gamma and undisturbed formation resistivity (GR-RT).

As shown in fig. 6, according to the distribution value range of volcanic lava divided in step S30, an intersection chart of natural gamma and undisturbed formation resistivity (GR-RT) is established, wherein the abscissa is a natural gamma value, the unit is API, and the ordinate is an undisturbed formation resistivity value, the unit is Ω·m; analyzing and dividing areas of volcanic lava large-scale distribution (overlapping locally due to the transition zone of the matrix); respectively determining upper and lower limit values of a distribution area of the volcanic lava major class, and/or establishing a linear relation according to the requirement; through the steps, volcanic lava lithology is divided into basic volcanic rock, neutral volcanic rock, acidic volcanic rock and secondary volcanic rock by utilizing the intersection plate of the natural gamma and the undisturbed formation resistivity (GR-RT), and the distribution areas of the basic volcanic rock, the neutral volcanic rock, the acidic volcanic rock and the secondary volcanic rock are divided; the upper and lower limit values of the respective distribution areas of the basic volcanic rock, the neutral volcanic rock, the acidic volcanic rock and the secondary volcanic rock are determined, and/or the respective linear relations of the basic volcanic rock, the neutral volcanic rock, the acidic volcanic rock and the secondary volcanic rock are established according to the requirements.

According to the technical scheme, the volcanic lava lithology is identified by drawing the intersection chart of the well logging curve sensitive to the volcanic lava lithology response based on conventional well logging data and combining the volcanic lava distribution area determined in the step S30, the operation steps are simple, the cost is low, and the volcanic lava lithology can be identified rapidly, efficiently and accurately.

When the volcanic lava major class (i.e., basic volcanic rock, neutral volcanic rock, acidic volcanic rock, and secondary volcanic rock) is classified in step S55, it may be determined whether a new intersection chart needs to be established to further classify the volcanic lithology of the basic volcanic rock, neutral volcanic rock, acidic volcanic rock, secondary volcanic rock, and the like of the next stage according to the distribution value range of the classified volcanic lava major class.

Preferably, as shown in fig. 1 to 4 and fig. 6 to 10, in the embodiment of the present invention, after step S55, the volcanic lithology recognition method further includes:

Step S65: selecting a plurality of logging curves sensitive to lithology of a volcanic lava major class from a standardized database;

step S75: and drawing a logging curve intersection plate capable of identifying lithology of different volcanic lava major categories, and classifying each lithology of the volcanic lava major categories.

Specifically, through step S55, the lithology of the volcanic lava is divided to obtain the major types of volcanic lava (i.e. basic volcanic rock, neutral volcanic rock, acidic volcanic rock and secondary volcanic rock), and the distribution areas of each major type of volcanic lava and the upper and lower limit values of the distribution areas of each major type of volcanic lava are determined; based on the step S55, step S65 is to select a plurality of logging curves with better identification effect, which can identify the lithology of each major class of volcanic lava from the standardized logging data database; step S65 utilizes standardized conventional logging data in a standardized logging data database to determine a plurality of logging curves which can identify lithology of the volcanic lava major class and have relatively good identification effect on the lithology of the volcanic lava major class, and lays a foundation for ensuring accurate identification of the lithology of the volcanic lava major class through the logging curves in the subsequent steps; step S75 is to draw intersection panels based on the above-mentioned multiple log curves in combination with the distribution areas of the volcanic lava major categories determined in step S55 on the basis of step S65, to identify lithology of the volcanic lava major categories, to divide the distribution areas of lithology of the volcanic lava major categories by the separately drawn intersection panels of the log curves, and to further determine upper and lower limit values of the distribution areas and/or to establish a linear relation.

In the technical scheme, based on conventional logging data, the lithology of each major class of volcanic lava is identified by drawing a cross plot of a logging curve sensitive to lithology response of each major class of volcanic lava in combination with the distribution area of the volcanic lava major class determined in the step S55, and the method has the advantages of simple operation steps and low cost; based on the step S45 and the step S55, the invention utilizes the thought of classifying and identifying the lithology of the volcanic rock in a grading manner, and the distribution area of the lithology of each major class of volcanic lava is rapidly divided by drawing a logging curve intersection plate so as to determine the distribution range of the lithology of each major class of volcanic lava, thereby realizing rapid identification of the lithology of each major class of volcanic lava. Through the steps, the lithology of each large class of volcanic lava can be rapidly, efficiently and accurately identified, and the method has higher popularization adaptability.

The identification of lithology of each major class of volcanic lava is not in sequence.

Specifically, when determining the lithology of the volcanic lava (i.e. determining that the volcanic lava is mainly basic volcanic rock, neutral volcanic rock, acidic volcanic rock and secondary volcanic rock), there is no sequence in further identifying the lithology of each of the volcanic lava, and the lithology of the basic volcanic rock, the neutral volcanic rock, the acidic volcanic rock or the secondary volcanic rock can be selected to be identified first according to actual conditions and actual needs.

Specifically, as shown in fig. 7, in the embodiment of the present invention, in step S65, the selected multiple logs sensitive to the lithology response of the basic volcanic are acoustic time difference (AC) and Compensation Neutron (CNL), and on the basis of step S65, the intersection of the logs capable of identifying lithology of different basic volcanic, which is drawn in step S75, is an intersection of acoustic time difference and compensation neutron (AC-CNL).

Judging to further identify the basic volcanic rock according to the divided distribution value range of the basic volcanic rock, and establishing a sound wave time difference and compensation neutron (AC-CNL) intersection plate, wherein the abscissa is the sound wave time difference value, the unit is mu s/ft, the ordinate is the compensation neutron value, and the compensation neutron value is a percentage; analyzing and dividing the region of lithology distribution of the basic volcanic rock; respectively determining upper and lower limit values of the distribution areas of each basic volcanic rock and/or establishing a linear relation according to the needs; by the steps, the basic volcanic lithology is classified into basalt, almond basalt and Xuanwu volcanic breccia by utilizing the intersection plate of the acoustic time difference and the compensation neutron (AC-CNL), the distribution areas of the basalt, the almond basalt and the Xuanwu volcanic breccia are divided, the upper limit value and the lower limit value of the respective distribution areas are determined, and/or the respective linear relation formula is established according to the requirement.

According to the technical scheme, based on conventional logging data, the distribution area of the basic volcanic rock determined in the step S55 is combined, and the basic volcanic rock property is identified by drawing the intersection chart of the logging curve sensitive to the response of the basic volcanic rock property.

Specifically, as shown in fig. 8, in the embodiment of the present invention, in step S65, the selected plurality of log curves sensitive to the lithology response of the neutral volcanic are natural Gamma (GR) and Density (DEN), and on the basis of step S65, the log curve intersection plate capable of identifying the lithology of different neutral volcanic drawn in step S75 is a natural gamma and density (GR-DEN) intersection plate.

Judging to further identify the neutral volcanic rock according to the distributed value range of the neutral volcanic rock, and establishing a natural gamma and density (GR-DEN) intersection plate, wherein the abscissa is a natural gamma value, the unit is an API, the ordinate is a density value, and the unit is g/cm ³; analyzing and dividing areas of lithology distribution of the neutral volcanic rock; respectively determining upper and lower limit values of respective distribution areas of various neutral volcanic rocks, and/or establishing a linear relation according to the needs; through the steps, the lithology of the neutral volcanic rock is divided into andesite, fusion tuff and andesite volcanic breccia by utilizing the natural gamma and density (GR-DEN) intersection plate, the distribution areas of the andesite, fusion tuff and andesite volcanic breccia are divided, the upper limit value and the lower limit value of the respective distribution areas are determined, and/or the respective linear relation is established according to the requirement.

According to the technical scheme, based on conventional logging data, the neutral volcanic lithology is identified by drawing the intersection chart of the logging curve sensitive to the response of the neutral volcanic lithology in combination with the distribution area of the neutral volcanic rock determined in the step S55, and the method is simple in operation steps, low in cost and capable of quickly, efficiently and accurately identifying the neutral volcanic lithology.

Specifically, as shown in fig. 9, in the embodiment of the present invention, in step S65, the selected multiple logs sensitive to the lithology response of the acid volcanic are Density (DEN) and acoustic time difference (AC), and on the basis of step S65, the log intersection graph capable of identifying lithology of different acid volcanic drawn in step S75 is a density and acoustic time difference (DEN-AC) intersection graph.

Judging to further identify the acid volcanic according to the distributed value range of the divided acid volcanic, and establishing a density and acoustic wave time difference (DEN-AC) intersection plate, wherein the abscissa is a density value, the unit is g/cm ³, and the ordinate is an acoustic wave time difference value, the unit is mu s/ft; analyzing and dividing the lithology distribution area of the acid volcanic rock; respectively determining upper and lower limit values of respective distribution areas of various acid volcanic rocks, and/or establishing a linear relation according to the needs; by the steps, the acidic volcanic lithology is classified into the England rock, the flow rock, the broken flow rock, the acidic tuff and the flow volcanic breccia by utilizing the density and acoustic time difference (DEN-AC) intersection plate, the distribution areas of the England rock, the flow rock, the broken flow rock, the acidic tuff and the flow volcanic breccia are divided, the upper limit value and the lower limit value of the respective distribution areas are determined, and/or the respective linear relation is established according to the requirement.

According to the technical scheme, the acidic volcanic lithology is identified by drawing the intersection graph of the logging curve sensitive to the response of the acidic volcanic lithology based on the conventional logging data and combined with the distribution area of the acidic volcanic rock determined in the step S55, and the method has the advantages of simple operation steps and low cost, and can be used for quickly, efficiently and accurately identifying the acidic volcanic lithology.

Specifically, as shown in fig. 10, in the embodiment of the present invention, in step S65, the selected multiple logs sensitive to the secondary volcanic lithology response are the Compensated Neutrons (CNL) and the Density (DEN), and on the basis of step S65, the log intersection pattern capable of identifying the different secondary volcanic lithologies drawn in step S75 is the compensated neutrons and the density (CNL-DEN) intersection pattern.

Judging and further identifying the secondary volcanic according to the divided distribution value range of the secondary volcanic, and establishing a compensation neutron and density (CNL-DEN) intersection plate, wherein the abscissa is a compensation neutron value, the compensation neutron value is a percentage, the ordinate is a density, and the unit is g/cm ³; analyzing and dividing a distribution area of the lithology of the secondary volcanic rock; respectively determining upper and lower limit values of respective distribution areas of various secondary volcanic rocks, and/or establishing a linear relation according to the needs; by the steps, sub volcanic lithology is classified into a normal porphyry, a two-long porphyry, a amphiphane and a disintegrated normal porphyry by utilizing the intersection chart of the density and the compensation neutrons (DEN-CNL), the distribution areas of the normal porphyry, the two-long porphyry, the amphiphane and the disintegrated normal porphyry are classified, the upper limit value and the lower limit value of the respective distribution areas are determined, and/or the respective linear relation is established according to the requirement.

According to the technical scheme, the secondary volcanic lithology is identified by drawing the intersection chart of the logging curve sensitive to the secondary volcanic lithology response by combining the distribution area of the secondary volcanic rock determined in the step S55 on the basis of conventional logging data, and the method is simple in operation steps, low in cost and capable of quickly, efficiently and accurately identifying the secondary volcanic lithology.

As shown in fig. 3, fig. 4, and fig. 7 to fig. 9, the volcanic lithology recognition method based on conventional logging data provided by the embodiment of the invention has a good recognition effect on the complete sequence lithology categories of basic volcanic rocks, neutral volcanic rocks and acidic volcanic rocks, can effectively distinguish volcanic corner conglomerates containing basic and neutral acidic matrixes, eliminates the influence of complex nomination of the volcanic rocks caused by the different matrixes, and improves the lithology recognition accuracy of an effective reservoir.

The invention relates to a volcanic lithology recognition method based on conventional logging scales, which utilizes conventional logging data to establish a set of rapid, low-cost and high-efficiency volcanic lithology recognition method, and has good recognition effect on volcanic breccia containing basic, medium and acidic matrixes.

Preferably, as shown in fig. 1 and 2, in an embodiment of the present invention, the volcanic lithology recognition method further includes the steps of:

Step S05: the lithology of the volcanic rock is named based on data obtained by one or more of open-end exploration, core observation, experimental analysis and sheet identification modes, so that a lithology naming database of the volcanic rock is obtained; and

Step S15: and establishing a lithology data base of the volcanic rock based on the lithology data of the volcanic rock obtained by the special logging methods such as imaging logging and/or element capturing.

Specifically, step S05 is to collect and sort out the data after open-head investigation, core observation, experimental analysis and sheet identification, and build a regional (secondary structure or basin category) standard volcanic lithology nomination database based on the basic research information (or data).

That is, step S05 is to collect and sort data (or basic research information) obtained by one or more of open-end survey, core observation, experimental analysis and sheet identification of the target area, and then name the lithology of the volcanic rock of the target area based on the data, and establish a standardized lithology-naming database of the volcanic rock.

Further, in step S05, the designation of the volcanic lithology or the classification of the volcanic lithology is to meet the national standard and industry standard issued by the national authorities (such as the institute of land mining, the institute of middle petroleum industry, etc.). Thus, according to the national standard and industry standard issued by the national authority, the lithology of the volcanic rock in the target area can be uniformly named, the influence of complex named after the volcanic rock contains different matrixes and different internal structural characteristics is eliminated, and the lithology recognition accuracy is improved.

Further, in the embodiment of the present invention, through step S05, a lithology naming database of volcanic rock standardized based on the regional (secondary structure or basin category) of the above-mentioned basic research information is established. That is, in the national standard and industry standard issued by the national authority, the standard designation of the volcanic lithology in a partial area (such as a secondary structure or basin category) is selected as the standard of the volcanic lithology designation of the target area, so that the standard designation range for designating the lithology of the volcanic in the target area can be reduced, the workload is reduced, the working efficiency is improved, and the unnormalization of the volcanic lithology designation of the target area is avoided.

Specifically, in step S15, volcanic lithology data picked up and identified by a special logging (mainly imaging logging) is collected and organized, a volcanic information base based on the special logging identification is established, that is, volcanic lithology data picked up and identified by a special logging method (mainly imaging logging) in a target area is collected and organized, and a volcanic lithology data base (that is, volcanic information base) based on the special logging method identification is established.

By establishing the lithology naming database of the volcanic rock and the lithology data database of the volcanic rock, the lithology category of the target area can be determined aiming at the geological characteristics of the research work area (namely the target area), namely, the lithology category of the target area can be determined according to the lithology data of the volcanic rock, which is obtained by the target area through the special logging methods such as open-end stepping investigation, core observation, experimental analysis, sheet identification modes, imaging logging, element capturing and the like, and the lithology category of the volcanic rock, which is required to be identified in the target area, is further determined; and the volcanic lithology category to be identified in the target area can be uniformly named according to the national standard and the industry standard issued by the national authority, so that the influence of complex naming generated by volcanic containing different matrixes and different internal structural characteristics is eliminated, and the lithology identification accuracy is improved.

Further, as shown in fig. 2, in the embodiment of the present invention, a standardized logging database, a lithology naming database of volcanic rock and a lithology database of volcanic rock are established through step S10, step S05 and step S15, and a unified database (i.e., the basic database in fig. 2) formed by the above three databases is established.

Further, in embodiments of the present invention, by comparison of the three databases described above, a logging item (i.e., log) sensitive to volcanic lithology response is preferred; specifically, for the lithology of volcanic rock in the same well depth in the target area, the lithology of volcanic rock can be respectively identified through a lithology naming database of volcanic rock and a lithology data database of volcanic rock, and meanwhile, the lithology of volcanic rock respectively identified through the three databases is identified by utilizing a standardized logging data database, and when the lithology of volcanic rock identified by utilizing the logging data database is consistent or similar to the lithology of volcanic rock identified through the lithology naming database of volcanic rock and the lithology data database of volcanic rock, the logging curve in the standardized logging data database is the logging curve which is sensitive to the lithology response of volcanic rock.

In the arrangement, the lithology classification of the volcanic rock to be identified in the target area can be determined through the lithology classification database of the volcanic rock and the lithology data database of the volcanic rock, and the lithology classification of the volcanic rock to be identified is uniformly classified according with the national standard and the industry standard issued by the national authority, so that the influence of complex classification of the volcanic rock due to the fact that the volcanic rock contains different matrixes and different internal structural characteristics can be eliminated; through a standardized logging data database, the thought of classifying and identifying volcanic lithology in a grading manner is utilized, a volcanic lithology intersection plate is established, the volcanic lithology is rapidly identified, the interference of reservoir structure factors on the volcanic lithology identification is eliminated, and the lithology identification accuracy of an effective reservoir is improved.

Of course, in an alternative embodiment not shown in the drawings, the volcanic lithology recognition method of the present invention may further include the following steps according to actual situations and actual needs:

Step S05: the lithology of the volcanic rock is named based on data obtained by one or more of open-end exploration, core observation, experimental analysis and sheet identification modes, so that a lithology naming database of the volcanic rock is obtained; or alternatively, the first and second heat exchangers may be,

Preferably, as shown in fig. 1 and fig. 2, in an embodiment of the present invention, the volcanic lithology recognition method further includes:

Step S80: and (3) comparing the lithology naming database of the volcanic rock obtained in the step (S05) with the lithology data database of the volcanic rock established in the step (S15) with the partitioned lithology of the volcanic rock, and judging the accuracy of the volcanic rock lithology recognition method on the lithology recognition of the volcanic rock.

Specifically, as shown in fig. 2 to 10, in the embodiment of the present invention, fig. 3 is a volcanic lithology category of a target area determined according to the lithology nomadic database in the base database and the data in the lithology data database in fig. 2, that is, the volcanic lithology category of the target area to be identified; fig. 4 to 10 are volcanic lithology categories of a target region identified by the volcanic lithology identification method of the present invention based on data in the logging data database in the base database of fig. 2.

In the above technical solution, the accuracy of the volcanic lithology recognition method of the present invention for volcanic lithology recognition may be obtained by comparing the volcanic lithology category of the target area identified in fig. 4 to 10 with the volcanic lithology category of the target area to be recognized, which is already determined in fig. 3. According to the embodiment of the invention, the volcanic lithology identification method has higher accuracy in identifying volcanic lithology. The identification method can be applied to other areas needing lithology identification.

Further, it can be inferred that the establishment of the standardized logging database, the lithology naming database of volcanic and the lithology database of volcanic and the establishment of the basic database are one of the necessary conditions for improving the adaptability of the identification accuracy of the lithology identification method of the present invention, and the lithology identification method of the present invention is still applicable to the new exploration areas without the lithology naming database of volcanic and/or the lithology database of volcanic, and has high popularization adaptability.

Of course, in an alternative embodiment not shown in the drawings, according to the actual situation and the actual needs, the volcanic lithology recognition method of the present invention further includes:

Step S80: and (3) comparing the lithology naming database of the volcanic rock obtained in the step (S05) or the lithology data database of the volcanic rock established in the step (S15) with the partitioned lithology of the volcanic rock to judge the accuracy of the volcanic rock lithology recognition method on the lithology recognition of the volcanic rock.

The operation of the present invention will be described in detail with reference to fig. 1 to 10.

The volcanic lithology recognition method has the following design ideas:

1. determining lithology categories to be identified according to geological features of a research work area;

2. based on conventional logging data, establishing each major lithology intersection plate in a grading classification manner;

3. and on the basis of the identification of the lithology of the major categories, establishing a second-level lithology intersection plate of each lithology of the major categories.

Further, the data of 9 conventional logging curves may be acquired from a plurality of logging series and interfered by different environments, and before the method is applied, systematic error correction needs to be performed on the data, and the systematic error correction is one of the necessary conditions for ensuring the standardization of the method; it should be noted that, the technical points and the processing procedure of the system error correction are conventional technical means in the art, and are not repeated here.

Wherein, the main lithology division mainly includes: the basic properties of volcaniclastic rock, tuff and volcanic lava, neutral, acidic, secondary volcanic (invading lithology) and the like. The division of the lithology major class is shown in fig. 3.

Further, the secondary lithology intersection panels include volcanic clastic rock, basic volcanic rock, neutral volcanic rock, acidic volcanic rock, secondary volcanic rock (invading lithology) type intersection panels, as shown in fig. 4 to 10. The dividing limit value of lithology determined by each primary lithology intersection plate is different according to regions and the time, period, scale, duration and intensity of volcanic eruption, and various volcanic properties are different.

The volcanic lithology recognition method has the following beneficial effects:

1. The method firstly carries out large-class division on various lithology, simplifies lithology categories and solves the problem of complex lithology categories;

2. According to the invention, by utilizing the thought of progressive hierarchical classification (namely hierarchical classification), lithology is firstly classified into major categories for intersection plate recognition, and then minor category intersection plate recognition is carried out step by step, so that volcanic lava such as basic, neutral, acidic and secondary volcanic rocks and minor lithology thereof can be recognized, and the method comprises the step of distinguishing complex lithology such as volcanic breccia containing basic, medium and acidic matrixes;

3. The lithology recognition plate established by the invention can rapidly and efficiently recognize volcanic lithology with low cost, and solves the problems of complex lithology, poor recognition precision of a single plate and the like.

According to the design thought, the specific operation mode of the embodiment of the invention is as follows:

Step S05: the lithology of the volcanic rock is named based on data obtained by one or more of open-end exploration, core observation, experimental analysis and sheet identification modes, so that a lithology naming database of the volcanic rock is obtained;

step S15: based on volcanic lithology data obtained by special logging methods such as imaging logging and/or element capturing, establishing a lithology data database of volcanic;

As shown in fig. 3, the lithology classification database of the volcanic rock and the lithology data database of the volcanic rock are established, so that the lithology classification of the volcanic rock in the target area can be determined, the classification of the lithology classification of the volcanic rock is required to meet the national standard and the industry standard issued by the national authority, and the lithology classification of the volcanic rock in the target area is uniformly classified according to the national standard and the industry standard.

Step S10: collecting conventional logging information of volcanic rock in a target area, and establishing a standardized logging information database based on the conventional logging information;

Establishing a lithology naming database of volcanic rock, a lithology data database of volcanic rock and a standardized logging data database through the steps S05, S15 and S10, and establishing a unified database (namely a basic database in FIG. 2) formed by the three databases;

By comparing the lithology naming database of the volcanic rock, the lithology data database of the volcanic rock and the standardized logging data database, the logging curve sensitive to the lithology response of the volcanic rock is preferred.

Step S20: selecting a plurality of logging curves sensitive to volcanic lithology from the standardized logging data database;

Step S30: based on the plurality of logging curves, drawing logging curve intersection plates capable of identifying different volcanic lithologies, dividing the volcanic lithologies, and determining the distribution range of volcanic clastic rock and/or volcanic lava;

As shown in fig. 4, a cross plot of natural gamma and undisturbed formation resistivity/acoustic time difference (GR-RT/AC) is established, volcanic lithology is divided into volcanic clastic rock and volcanic lava, distribution areas of the volcanic clastic rock and the volcanic lava are divided, upper and lower limit values of the respective distribution areas are determined, and the respective distribution value areas are determined.

(The following is not a sequence for identifying lithology of volcaniclastic rock and volcaniclastic rock)

Step S50: drawing a logging curve intersection plate capable of identifying different volcaniclastic lithologies, and dividing the volcaniclastic lithologies to obtain a volcaniclastic rock class;

As shown in fig. 5, a natural gamma-density (GR-DEN) intersection plate is established, volcaniclastic lithology is divided, the volcaniclastic lithology is divided into tuff mudstone and tuff sandstone, distribution areas of the tuff mudstone and the tuff sandstone are divided, upper and lower limit values of the respective distribution areas are determined, and the respective distribution value areas are determined.

As shown in fig. 6, a cross plot of natural gamma and undisturbed formation resistivity (GR-RT) is established, the volcanic lava lithology is divided into basic volcanic rock, neutral volcanic rock, acidic volcanic rock and secondary volcanic rock, the distribution areas of the basic volcanic rock, neutral volcanic rock, acidic volcanic rock and secondary volcanic rock are divided, the upper limit value and the lower limit value of each distribution area are determined, and each distribution value area is determined.

(The following is a description of the identification of lithology of each major class of lava without a sequence)

step S75: drawing a logging curve intersection plate capable of identifying lithology of different volcanic lava major categories, and classifying each lithology of the volcanic lava major categories;

As shown in fig. 7, a sound wave time difference and compensated neutron (AC-CNL) intersection plate is established, basic volcanic lithology is classified into basalt, almond basalt and basaltic volcanic breccia, and the distribution areas of basalt, almond basalt and basaltic volcanic breccia are classified, the upper and lower limit values of the respective distribution areas are determined, and the respective distribution value areas are determined.

As shown in fig. 8, a natural gamma and density (GR-DEN) intersection plate is established, the lithology of the neutral volcanic is classified into a subclass, the lithology of the neutral volcanic is classified into andesite, fusion tuff and andesite, the distribution areas of the andesite, fusion tuff and andesite are classified, the upper and lower limit values of the respective distribution areas are determined, and the respective distribution value areas are determined.

As shown in fig. 9, a density and acoustic time difference (DEN-AC) intersection chart is established, acidic volcanic lithology is classified into an intrinsic rock, a flow rock, a broken flow rock, an acidic tuff and a flow volcanic breccia, distribution areas of the intrinsic rock, the flow rock, the broken flow rock, the acidic tuff and the flow volcanic breccia are classified, upper and lower limit values of the respective distribution areas are determined, and the respective distribution value areas are determined.

As shown in fig. 10, a density and compensation neutron (DEN-CNL) intersection chart is established, sub-volcanic lithology is classified into a major porphyry, a two major porphyry, a amphiphany and a disintegrated major porphyry, distribution areas of the major porphyry, the two major porphyry, the amphiphany and the disintegrated major porphyry are divided, upper and lower limit values of the respective distribution areas are determined, and the respective distribution value areas are determined.

As shown in fig. 1 to 10, the volcanic lithology classification of the target area identified by the volcanic lithology identification method of the present invention in fig. 4 to 10 is compared with the volcanic lithology classification of the target area to be identified according to the basic database in fig. 2 in fig. 3, so that the volcanic lithology identification method based on conventional logging data for identifying volcanic lithology of the present invention has high accuracy in identifying volcanic lithology, and further, it can be inferred that the volcanic lithology identification method of the present invention is still applicable to the new exploration area without the volcanic lithology naming database and/or the volcanic lithology data database of volcanic rock.

From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: according to the conventional logging measurement principle, through analyzing and comparing the determined logging response characteristics of standard volcanic lava and volcanic clastic rock and differences thereof, a cross-plot is manufactured by means of the lithology scales of the well core and the special logging, which are well-logging curves sensitive to the volcanic lithology response, preferably, the volcanic clastic rock and the volcanic lava are distinguished firstly through the cross-plot, the volcanic clastic rock is subdivided secondly, the volcanic clastic rock is divided thirdly (basic, medium, acid and secondary volcanic rock) and finally, various minor categories in the major categories are divided step by step according to the volcanic lava major categories (basic, medium, acid and secondary volcanic rock), in particular, the volcanic clastic rock containing basic, medium and acid matrixes is distinguished. The invention is based on conventional logging information, can solve the problems that in the well section without coring and special logging and with conventional logging curves, a volcanic lithology recognition plate is built by utilizing the thought of classification, main subclasses in the volcanic main subclasses are rapidly recognized, the influence of complex nomination of the volcanic caused by different matrixes and different internal structural characteristics is eliminated, the large class recognition and the distinction of acid and alkali are taken as the leading factors, and the interference of reservoir structural factors is eliminated, and provides a volcanic lithology recognition method capable of rapidly, efficiently and accurately recognizing the volcanic lithology, meanwhile, volcanic breccia containing matrixes, medium and acidic matrixes can be effectively distinguished, the lithology recognition accuracy of an effective reservoir is improved, the operation is simplified, the cost is reduced, the popularization adaptability is increased, and the world-level problem of great difficulty in carrying out the volcanic lithology recognition based on conventional logging is solved. The lithology recognition accuracy is high, the operation is simple and convenient, the method is suitable for being used in any logging, measuring, drilling site and scientific research work with logging curves, can be used for assisting in rapidly recognizing lithology, improves the effective reservoir lithology recognition accuracy, and increases the oil and gas exploration and development benefits.

It will be apparent that the embodiments described above are merely some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present application. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

It should be noted that the terms "first," "second," and the like in the description and the claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that embodiments of the application described herein may be implemented in sequences other than those illustrated or otherwise described herein.

The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The volcanic lithology recognition method is characterized by comprising the following steps of:

Step S30: based on the plurality of logging curves, drawing logging curve intersection plates capable of identifying different volcanic lithologies, dividing the volcanic lithologies, and determining the distribution range of volcanic clastic rock and/or volcanic lava; the logging curve intersection plate capable of identifying different volcanic lithology is an intersection plate of natural gamma and undisturbed stratum resistivity/acoustic time difference (GR-RT/AC);

step S45: selecting a plurality of logging curves sensitive to volcanic lava lithology from the standardized database;

step S55: drawing a logging curve intersection plate capable of identifying different volcanic lava lithologies, and dividing the volcanic lava lithologies to obtain volcanic lava major categories; establishing a natural gamma and undisturbed stratum resistivity (GR-RT) intersection plate, dividing volcanic lava lithology, and dividing the volcanic lava lithology into basic volcanic rock, neutral volcanic rock, acidic volcanic rock and secondary volcanic rock;

step S65: selecting from the standardized database a plurality of well logs sensitive to lithology of the volcanic lava major class;

Step S75: drawing a logging curve intersection graph capable of identifying different lithologies of the volcanic lava major categories, classifying each lithology of the volcanic lava major categories, establishing a sound wave time difference and compensation neutron (AC-CNL) intersection graph, classifying basic volcanic lithology into basalt, almond basalt and Xuanwu volcanic corner conglomerate; establishing a natural gamma and density (GR-DEN) intersection plate, classifying the lithology of the neutral volcanic rock into an andesite, a fusion tuff and an andesite volcanic breccia; establishing a density and sound wave time difference (DEN-AC) intersection plate, classifying acidic volcanic lithology into subclasses, and classifying the acidic volcanic lithology into England rock, rock flow, broken rock flow, acidic tuff and volcanic breccia; and (3) establishing a density and compensation neutron (DEN-CNL) intersection plate, classifying the lithology of the secondary volcanic rock into a major porphyry, a two-major porphyry, a amphiphanite and a cracked major porphyry.

2. The method according to claim 1, wherein when the volcanic lithology is the volcaniclastic rock, after the step S30, the method further comprises:

Step S40: selecting a plurality of logs from the standardized database that are sensitive to volcaniclastic rock lithology;

Step S50: and drawing a logging curve intersection plate capable of identifying different volcaniclastic lithologies, and dividing the volcaniclastic lithologies to obtain volcaniclastic rock major categories.

3. The volcanic lithology recognition method according to claim 2, wherein after the step S50, the volcanic lithology recognition method further comprises:

Step S60: selecting from the standardized database a plurality of logs sensitive to lithology of the pyroclastic rock broad class;

Step S70: and drawing a logging curve intersection plate capable of identifying lithology of different pyroclastic rock major categories, and classifying each lithology of the pyroclastic rock major categories.

4. The method of claim 2, wherein the log intersection capable of identifying different volcaniclastic lithologies is a natural gamma-density (GR-DEN) intersection.

5. The volcanic lithology recognition method according to any one of claims 1 to 4, wherein the volcanic lithology recognition method further comprises the steps of:

Step S05: the lithology of the volcanic rock is named based on data obtained by one or more of open-end exploration, core observation, experimental analysis and sheet identification modes, so that a lithology naming database of the volcanic rock is obtained; and/or the number of the groups of groups,

Step S15: and establishing a lithology data database of the volcanic rock based on the lithology data of the volcanic rock obtained by the imaging logging and/or the element capturing logging mode.

6. The volcanic lithology recognition method of claim 5, further comprising:

Step S80: and (3) comparing the lithology naming database of the volcanic rock obtained in the step (S05) and/or the lithology data database of the volcanic rock established in the step (S15) with the partitioned lithology of the volcanic rock, and judging the accuracy of the lithology recognition method of the volcanic rock.