CN-121994758-A - Method for determining Tibetan generation of deep concave area of land-phase fracture and subsidence lake basin

CN121994758ACN 121994758 ACN121994758 ACN 121994758ACN-121994758-A

Abstract

The invention belongs to the field of petroleum geological exploration, in particular relates to a method for determining the age of a land phase fracture and subsidence lake basin deep concave region, and aims to solve the problems that the land phase fracture and subsidence lake basin deep concave region can only be obtained semi-quantitatively to form the age of the Tibetan, and misjudgment is easily caused to the age of the land phase fracture and subsidence lake basin deep concave region. The method comprises the steps of determining an oil well section, selecting sandstone of a developing calcite cementing agent as a sample, preparing a sheet, determining the type of a fluid inclusion, further determining the type of an oil inclusion, obtaining the similarity of rare earth element distribution modes of the sheet, determining the cementing period of the sheet, selecting a sheet which contains primary inclusion and is the same cementing period and is prepared into a circular target sample, carrying out U, pb element scanning on the circular target sample, and carrying out U-Pb age calculation through a graphical method to obtain the age of the formation of the deep concave region of the land-phase fracture lake basin. The invention realizes quantitative analysis of the age of the adult in the deep concave area of the land-phase fracture and subsidence lake basin, and improves the accuracy of judgment of the age of the adult.

Inventors

CHEN JIAXU
WANG GUAN
CHEN CHANGWEI
ZOU LEILUO
LIU GUOQUAN
CUI YU
ZHU HUAHUI
ZHOU FENGCHUN
DONG WENTAO
XU WENJING

Assignees

中国石油天然气股份有限公司

Dates

Publication Date: 20260508
Application Date: 20241101

Claims (10)

1. A method for determining the age of a Tibetan for a deep depression of a land subsidence lake basin, the method comprising the steps of: s10, determining an oil-containing well section of a deep concave area of a land phase fracture and subsidence lake basin, selecting sandstone of a developing calcite cementing agent in the oil-containing well section as a sample, cleaning the sample and preparing a sheet; S20, observing fluid inclusion of the sheet to determine the type of the fluid inclusion, selecting oil inclusion and determining the type of the oil inclusion according to the type of the fluid inclusion, wherein the oil inclusion type comprises primary inclusion and secondary inclusion; S30, selecting a set number of points from a sheet containing primary inclusion to perform micro-area rare earth element test, obtaining the similarity of rare earth element distribution modes of the sheet, and further confirming the cementing period of the sheet; and S40, carrying out U, pb element scanning on the circular target sample, and carrying out U-Pb age calculation through a graphic method after scanning, so as to obtain the age of the deep concave area of the land fracture lake basin.
2. The method for determining the age of a Tibetan for a deep concave area of a land fracture lake basin according to claim 1, wherein the method comprises the steps of observing fluid inclusion of the sheet, determining the type of the fluid inclusion, selecting oil inclusion according to the type of the fluid inclusion and determining the type of the oil inclusion, and comprises the following steps: determining the type of the fluid inclusion by observing whether the fluid inclusion of the sheet has fluorescent display, thereby selecting an oil inclusion; And observing the distribution characteristics of the oil inclusion under the transmitted light, and judging whether the oil inclusion is a primary inclusion or a secondary inclusion.
3. The method for determining the age of a Tibetan for a deep concave area of a land phase disruption basin according to claim 2, wherein micro-area rare earth element testing is performed at a selected set number of points on a sheet containing primary inclusion to obtain the rare earth element distribution pattern similarity of the sheet, and the method comprises the following steps: Micro-area rare earth element testing is carried out on a set number of points selected from the sheet containing the primary inclusion to obtain the content of rare earth elements, wherein the rare earth elements comprise Ce element and Eu element; Normalizing the rare earth element content, and calculating the normalized rare earth element ratio; If the rare earth element ratio corresponding to the point of the first percentage is set to be in the second percentage range of the average value of the rare earth element ratios, the rare earth element distribution modes of the thin slices are considered to be similar, otherwise, the rare earth element distribution modes of the thin slices have larger difference.
4. The method for determining the Tibetan generation of the deep concave area of the land fracture lake basin according to claim 3, wherein the normalized rare earth element ratio is calculated by the method of rare earth element ratio=rare earth element content/rare earth element content, wherein the rare earth element content represents the normalized rare earth element content of the australian shale of the back-to-the-ancient universe.
5. A method of determining the age of a Tibetan for a deep depression of a land fracture lake basin according to claim 3 wherein the sheet is identified for a period of cementing comprising: if the cathode luminescence color of the flake is more uniform and the rare earth element distribution mode is more similar, the flake is calcite formed in the same cementing period; If the cathodoluminescence color of the flake shows a large difference in multiple or rare earth element partitioning modes, the flake is calcite formed by multi-stage cementation.
6. The method for determining the Tibetan generation of the deep concave area of the land phase fracture lake basin according to claim 5, wherein the method is characterized in that U, pb element scanning is carried out on the circular target sample, and U-Pb age calculation is carried out through a graphic method after scanning, and comprises the following steps: Carrying out U, pb element scanning on the circular target sample, obtaining 207 Pb/ 206 Pb and 238 U/ 206 Pb values of a plurality of measuring points of the circular target sample, and carrying out U-Pb age calculation through a graphic method.
7. The method for determining the age of a Tibetan for a deep concave area of a continental facies fracture lake basin according to claim 6, wherein the calculation of the age of U-Pb is performed by a graphical method comprising: The accumulation process of radioactive elements 206 Pb + and 207 Pb + in the circular target-like calcite is as follows: 206 Pb + ＝ 238 U×(e λ1t -1) 207 Pb + ＝ 235 U×(e λ2t -1) Wherein 206 Pb + is 206 Pb value of radioactive origin, 207 Pb + is 207 Pb value of radioactive origin, λ1= 1.55125e -10 ,λ2＝9.8485e -10 , t is age of calcite; In the Terra-Wasserburg harmonic plot of calcite, AB is the isochrone fitted to the real points of the circular target samples 207 Pb/ 206 Pb and 238 U/ 206 Pb, the lower intersection point a of the isochrone AB and the harmonic line represents the 207 Pb + / 206 Pb + and 238 U/ 206 Pb + values of the radioactive cause, the intersection point B in the isochrone AB and the ordinate represents the normal lead composition of the circular target sample ( 207 Pb/ 206 Pb) Ordinary use , the abscissa of E represents the real points 238 U/ 206 Pb and 207 Pb/ 206 Pb of the circular target sample, C is the straight line intersection point of E and the longitudinal axis, F is the straight line intersection point of E and the transverse axis, E represents the real/measured sample point, D is the straight line intersection point of a and the longitudinal axis, according to the principle of similar triangles: Wherein, the Substituting AD, AF, BD, EF values into The method can obtain: Wherein, the And Are all of known quantity, thus can obtain Will be Substituting the cumulative process equation for the radioactive element 206 Pb + , the age of U-Pb of the sample can be calculated.
8. A system for determining the age of a Tibetan for a deep depression of a land subsidence lake basin, the system comprising: the sample acquisition module is configured to determine an oil-containing well section of a deep concave area of a land phase fracture sink lake basin, and select sandstone of a developing calcite cementing agent in the oil-containing well section as a sample, wash the sample and make a sheet; The type determining module is configured to observe the fluid inclusion of the sheet and determine the type of the fluid inclusion, and select an oil inclusion and determine the type of the oil inclusion according to the type of the fluid inclusion, wherein the oil inclusion type comprises a primary inclusion and a secondary inclusion; the testing module is configured to select a set number of points on a sheet containing primary inclusion to carry out micro-area rare earth element testing, obtain the similarity of rare earth element distribution modes of the sheet, and further confirm the cementing period of the sheet; and the Tibetan generation acquisition module is configured to scan the circular target sample by U, pb elements, and perform U-Pb age calculation through a graphic method after scanning so as to obtain the Tibetan generation of the deep concave area of the land-phase fracture lake basin.
9. An electronic device, comprising: and a memory communicatively coupled to at least one of the processors, wherein the memory stores instructions executable by the processor for execution by the processor to implement a method of determining land phase fracture, lake basin, and age of the collection as claimed in any one of claims 1-7.
10. A computer readable storage medium having stored thereon computer instructions for execution by the computer to implement a method of determining a land phase fracture, lake basin deep sink, tibetan generation as claimed in any one of claims 1 to 7.

Description

Method for determining Tibetan generation of deep concave area of land-phase fracture and subsidence lake basin Technical Field The invention belongs to the field of petroleum geological exploration, and particularly relates to a method, a system, electronic equipment and a computer readable storage medium for determining the Tibetan generation of a deep concave area of a land phase fracture and subsidence lake basin. Background The deep concave area of the land phase fracture sinking lake basin refers to a negative construction unit which surrounds the sedimentation center of the lake basin, has a burial depth greater than the mature hydrocarbon generation threshold depth of the land phase hydrocarbon source rock and is formed by a central concave part and a peripheral part low slope, is generally overlapped with the hydrocarbon generation center of the lake basin, and has the characteristics of non-development of fracture, stable construction, compact reservoir, preferential near accumulation of oil gas and centrifugal hydrocarbon supply to the periphery. The deep concave area of the land phase fracture and subsidence lake basin is not developed due to structural trap, physical property deviation of a reservoir is large, the depth of burial is large, the exploration cost is high, and the deep concave area is not the first choice for initial oil and gas exploration of the basin. However, after the main body of the lake basin construction zone and the slope zone reach the high-maturity exploration stage, with the innovation of exploration technologies, especially after the cost of reservoir reconstruction technologies is continuously reduced, the deep concave zone becomes an important target zone for searching strategic resources for succession and for searching sustainable development strategic resources. The source and storage integration is a typical characteristic of oil reservoirs in deep concave areas of the land-phase fracture and subsidence lake basin, and the precedence relationship between the oil and gas reservoir age and the deep burying time of the reservoir is one of key factors for the formation of petroleum scale enrichment in the deep concave areas of the land-phase fracture and subsidence lake basin, so that fine resolution of the deep concave areas of the land-phase fracture and subsidence lake basin is particularly important for the formation of the reservoir age. The fluid inclusion method is a classical method for judging the age of the reservoir, and the age of the reservoir is obtained by utilizing uniform temperature projection of a saline inclusion associated with an oil inclusion to the buried history, but the method has the following three problems in determining the age of the reservoir of a deep concave region of a land-phase fracture lake basin, namely ① is the development trend of oil and gas reservoir system research, and the fluid inclusion method can only semi-quantitatively determine the age of the reservoir and cannot meet the requirements of fine exploration nowadays. ② The saline inclusion in the deep concave area of the land phase fracture lake basin is relatively developed, the difficulty of judging whether the saline inclusion is associated with the oil inclusion is great, and the measured uniform temperature of the saline inclusion does not need to represent the filling temperature of crude oil. ③ The deep concave area of the land phase fracture sink lake basin is usually more than 3500m, the reservoir temperature is high, for the saline water inclusion associated with the oil inclusion in the same period, the uniform temperature change is usually more than 15 ℃, and different temperature points are selected as the temperature when the crude oil is filled, so that different storage time can be obtained. At present, a method for precisely determining the age of the deep concave area of the land-phase fracture sink lake basin is lacked. Disclosure of Invention In order to solve the above problems in the prior art, that is, in order to solve the problem that the prior art only can semi-quantitatively obtain the hidden generation of the land phase fracture and subsidence lake basin deep concave area, and the difficulty of judging whether the brine inclusion is associated with the oil inclusion is large, and the uniform temperature variation range of the brine inclusion is wide, the problem that the hidden generation of the land phase fracture and subsidence lake basin deep concave area is easy to be misjudged is solved, the first aspect of the invention provides a method for determining the hidden generation of the land phase fracture and subsidence lake basin deep concave area, which comprises the following steps: s10, determining an oil-containing well section of a deep concave area of a land phase fracture and subsidence lake basin, selecting sandstone of a developing calcite cementing agent in the oil-containing well section as a sample, cleaning the sample and pre