CN-122018020-A - Underground cream salt rock layer identification method, system, equipment and storage medium

CN122018020ACN 122018020 ACN122018020 ACN 122018020ACN-122018020-A

Abstract

The invention provides a method, a system, electronic equipment and a storage medium for identifying an underground cream salt rock layer, wherein the method comprises the steps of obtaining magnetotelluric frequency data of an underground rock layer and generating a magnetotelluric frequency CYT curve; obtaining a first difference parameter CG1 according to the difference between the maximum extreme value envelope line LOG_MAX and the minimum extreme value envelope line LOG_MIN of the magnetotelluric frequency CYT curve, performing trend fitting based on the magnetotelluric frequency CYT curve to obtain a fitting straight line CNN, obtaining the difference between the magnetotelluric frequency CYT curve and the fitting straight line CNN to obtain a second difference parameter CG2, and judging and identifying the cream salt rock of the underground target stratum based on the obtained first difference parameter CG1 and the second difference parameter CG 2. The invention can effectively realize the accurate identification of the clastic rock stratum cream salt rock, can predict the development condition of the cream salt rock at the un-drilled section in drilling, and plays an important role in avoiding drilling accidents.

Inventors

LI CHANG
Wang Mengxiu
CHANG SHAOYING
QIAO ZHANFENG
WU JIN

Assignees

中国石油天然气集团有限公司

Dates

Publication Date: 20260512
Application Date: 20241112

Claims (11)

1. An underground cream salt layer identification method is characterized by comprising the following steps: Acquiring magnetotelluric frequency data of an underground stratum, and generating a magnetotelluric frequency CYT curve; Obtaining a first difference parameter CG1 according to the difference between the maximum extreme value envelope line LOG_MAX and the minimum extreme value envelope line LOG_MIN of the magnetotelluric frequency CYT curve; trend fitting is carried out based on a magnetotelluric frequency CYT curve, so that a fitting straight line CNN is obtained; obtaining a difference value between a magnetotelluric frequency CYT curve and a fitting straight line CNN to obtain a second difference parameter CG2; And judging and identifying the cream rock of the underground target stratum based on the obtained first difference parameter CG1 and the second difference parameter CG 2.
2. The method for identifying an underground gypsum salt rock layer according to claim 1, wherein the magnetotelluric frequency CYT curve has the following expression: CYT(i)=1000*(1/F(i)-depth(i)*5)/0.2 i=1,2,...,M wherein F is the measured magnetotelluric frequency data, depth is the stratum depth corresponding to the magnetotelluric frequency data, and M is the sampling point number of the magnetotelluric frequency data.
3. The method for identifying an underground gypsum salt bed as set forth in claim 2, wherein: The extraction method of the maximum extremum envelope line LOG_MAX comprises the following steps: LOG_MAX(j)=CYT(i) CYT(i)>CYT(i-1)&&CYT(i)>CYT(i+1) wherein, M is the number of sampling points of the magnetotelluric frequency data, and N represents the number of extreme points of a magnetotelluric frequency CYT curve; the extraction method of the minimum extremum envelope line LOG_MIN comprises the following steps: LOG_MIN(j)=CYT(i) CYT(i)<CYT(i-1)&&CYT(i)<CYT(i+1) wherein, i=2, 3, & gt, M-1;j =1, 2, & gt, N, M is the number of sampling points of the magnetotelluric frequency data, and N is the number of extreme points of the magnetotelluric frequency CYT curve.
4. A method of identifying an underground cream salt bed as defined in claim 3, wherein: the first difference parameter CG1 is calculated in a manner of CG1 (j) = |log_max (j) -log_min (j) |, where j=1, 2. The first difference parameter CG1 is the width between the maximum extreme value envelope line and the minimum extreme value envelope line, and the first difference parameter CG1 is proportional to the amplitude of the magnetotelluric frequency CYT curve when the curve fluctuates.
5. The method for identifying an underground gypsum salt rock layer according to claim 2, wherein trend fitting is performed based on a magnetotelluric frequency CYT curve, so as to obtain a fitting straight line CNN, and the expression of the fitting straight line CNN is as follows: CNN(i)=a*depth+b wherein i=1, 2,..m, where M is the number of sampling points of magnetotelluric frequency data, a and b represent fitting coefficients obtained by linear regression analysis of magnetotelluric frequency CYT curves, depth represents the depth of the subsurface target formation, CNN (i) represents the value after fitting of the sampling points, CNN represents the straight line after fitting, and is drawn from all the values of CNN (i).
6. The method for identifying an underground gypsum salt bed according to claim 5, wherein: The expression of the second difference parameter CG2 is CG2 (i) =cnn (i) -CYT (i), where i=1, 2.
7. The method for identifying an underground gypsum salt bed as set forth in claim 6, wherein: The second difference parameter CG2 represents the difference between the magnetotelluric frequency CYT curve and the CNN fitting trend line, specifically, the value of CG2 expresses the offset amplitude of the fitting straight line CNN in the magnetotelluric frequency CYT curve, and the larger the value of CG2, the larger the explanatory amplitude and the higher the stratum resistivity; If the parameter CG2 is greater than 0, the fitting straight line CNN is shown to be on the right side of the magnetotelluric frequency CYT curve, and the magnetotelluric frequency CYT curve is shown to be biased leftwards, and the resistivity is high; if the parameter CG2 is smaller than 0, it indicates that the fitting straight line CNN is on the left side of the magnetotelluric frequency CYT curve, which indicates that the magnetotelluric frequency CYT curve is biased to the right, and the resistivity is low.
8. A method of identifying an underground cream-rock layer as claimed in any one of claims 1 to 7, wherein: the specific judgment standard is that when the first difference parameter CG1 is smaller than a first judgment threshold value and the second difference parameter CG2 is larger than a second judgment threshold value, the current stratum is the cream rock.
9. An underground cream-rock layer identification system, comprising: the CYT curve acquisition module is used for acquiring magnetotelluric frequency data of the underground stratum and generating a magnetotelluric frequency CYT curve; The first calculation module is used for obtaining a first difference parameter CG1 according to the difference between the maximum extremum envelope line LOG_MAX and the minimum extremum envelope line LOG_MIN of the magnetotelluric frequency CYT curve; The second calculation module is used for performing trend fitting on the magnetotelluric frequency CYT curve to obtain a fitting straight line CNN, and then solving the difference between the magnetotelluric frequency CYT curve and the fitting straight line CNN to obtain a second difference parameter CG2; and the judging and identifying module is used for judging and identifying the cream-rock of the underground target stratum by using the obtained first difference parameter CG1 and the second difference parameter CG 2.
10. An electronic device comprising a memory and a processor, the memory having stored therein a computer program, wherein execution of the computer program by the processor causes the processor to perform a method of identifying an underground gypsum-salt layer as claimed in any one of claims 1 to 8.
11. A computer storage medium having stored thereon a computer program, which when executed by a processor implements a method of identifying an underground gypsum-salt layer according to any one of claims 1 to 8.

Description

Underground cream salt rock layer identification method, system, equipment and storage medium Technical Field The invention belongs to the technical field of petroleum geological exploration, and particularly relates to a method, a system, equipment and a storage medium for identifying an underground cream salt rock layer. Background The identification of underground paste salt rock stratum is an important task in the fields of geological exploration and resource development, and has profound effects on oil and gas exploration, mineral resource evaluation, geological environment research and the like. Because of the unique physical and chemical properties of the salt-gypsum rock stratum, the salt-gypsum rock stratum is closely related to the formation and distribution of oil and gas reservoirs, and therefore, the accurate identification of the underground salt-gypsum rock stratum has important significance for guiding the exploration and development of resources. However, the identification of subterranean paste formations is not easy. First, the layers of cream salt rock are typically buried deep in the subsurface, covered and compacted by overlying strata, often with significant changes in their physical and geochemical characteristics, which presents a significant challenge for identification work. Secondly, the underground geological structure is complex and changeable, and the cream salt rock layer can be distributed with other rock layers in a staggered way, so that the identification work is more difficult. In addition, conventional geological exploration methods, such as drilling and logging, while capable of providing direct formation information, are costly and destructive to the formation, and are difficult to meet the needs of large scale exploration. To overcome these difficulties, researchers are continually exploring new methods of identifying underground gypsum and salt formations. Geophysical prospecting techniques, such as seismic prospecting, are increasingly becoming a research hotspot. Seismic exploration can indirectly infer the structure and properties of formations by measuring the propagation and reflection characteristics of subsurface formations for seismic waves. However, when the seismic exploration is used for processing deep and complex stratum, the resolution and accuracy are often limited, the resolution of the seismic exploration depends on well logging and seismic interpretation, but the resolution of seismic data is limited (about 20-30m deep), the identification accuracy of the thin-layer gypsum rock is low, the well logging accuracy is high, the well logging is limited by well drilling positions, and if well logging data cannot be provided in places without well drilling, the comprehensive production technology requirements cannot be met. Thus, identification of subterranean gypsum formations presents a number of challenges. How to combine various exploration technologies, improve identification precision and efficiency, and how to process exploration data under complex geological conditions, reduce explanation uncertainty, and predict the development condition of the unground section of the cream salt rock is a problem to be solved at present. Therefore, the development of an efficient, accurate and economic underground cream-salt rock layer identification method has important significance for promoting the development of the geological exploration and resource development field. Disclosure of Invention Aiming at the defects existing in the prior art, the invention provides a method, a system, equipment and a storage medium for identifying an underground cream-rock layer. When electromagnetic waves penetrate through the paste rock stratum, the vibration frequency is reduced to form asymmetric vibration due to the fact that the sand body absorbs battery wave energy, so that data points in a small layer are increased (namely the number of periods is increased), and the characteristics that mud rock is opposite to the sand body are utilized, the relation between the electromagnetic wave frequency and the porosity of the stratum is reflected through a geodetic electromagnetic frequency curve (CYT curve), the sand body and the mud rock can be clearly distinguished, and the recognition precision and efficiency of the underground paste salt rock stratum are improved. The invention is realized by the following technical scheme: in one aspect of the embodiment of the invention, an underground paste salt layer identification method is provided, and the method comprises the following steps: Step 1, acquiring magnetotelluric frequency data of an underground stratum, and generating a magnetotelluric frequency CYT curve; step 2, obtaining a first difference parameter CG1 according to the difference between the maximum extremum envelope line LOG_MAX and the minimum extremum envelope line LOG_MIN of the magnetotelluric frequency CYT curve; Step 3, trend fitting is carried out based on