CN-115658824-B - Method for recovering palaeodynamic conditions of sedimentary basin

Abstract

The invention belongs to the technical field of sedimentary basin uranium ore exploration, and particularly relates to a method for recovering palaeodynamic conditions of a sedimentary basin. The method comprises the following steps of determining a research area structure evolution process and uranium ore formation period, extracting drilling data, drawing a drawing, and recovering an archaic hydrodynamic condition. According to the invention, based on the research of the structural evolution and the uranium ore formation age relationship, an ancient topography map, an ancient geogram, a lithology distribution map and the like of the uranium ore formation action period of the last period are compiled through a drilling database.

Inventors

• LIN XIAOBIN
• ZHANG YUNLONG
• JIA LICHENG
• XING ZUOCHANG
• TIAN MINGMING
• SHI QINGPING
• LI ZHENZHEN

Assignees

• 核工业北京地质研究院

Dates

Publication Date

20260512

Application Date

20221011

Claims (1)

1. 1. The method for restoring the paleo-hydrodynamic condition of the sedimentary basin is characterized by comprising the following steps of: The method comprises the steps of (1) determining a research area structure evolution process and uranium ore formation period, wherein the step (1) specifically comprises the following steps: The method comprises the steps of (1.1) determining the structural evolution process of a research area, collecting the data of the existing rock apatite fission track year, and obtaining the main structural evolution stage of the research area by combining the data of the structural evolution history of the area when the data are less and the rock sample is required to be collected in a supplementary mode for the apatite fission track year; Aiming at uranium ore beds in a research area, collecting uranium lead isotope data of existing uranium ores, and when the data are less, supplementing and collecting uranium ore samples to carry out uranium lead isotope analysis, and uniformly carrying out isochrone age calculation fitting of the uranium ore beds by utilizing the data to obtain main ore forming periods of the uranium ore beds; Comparing the structural evolution stage obtained by statistics in the step (1.1) with the uranium ore formation stage calculated in the step (1.2), analyzing the relation between the structural evolution of the research area and the uranium ore formation stage, wherein each large-scale structural lifting activity can cause the deposition interruption of the regional stratum, and if the large-scale structural activity of the last time is consistent with the large-scale uranium ore formation stage, considering that the large-scale structural activity of the last time causes the uranium ore formation effect of the research area t period, and determining the deposition interruption period and the overlying stratum of the uranium ore formation stage t according to the regional stratum year representation; Step (2), extracting drilling data; collecting geological logging data of various boreholes in a finishing research area, and totally eliminating the overburden stratum data determined in the step (1.3) by taking the deposition interruption period where the last uranium ore formation working period t determined in the step (1.3) is located as a boundary point; drawing a drawing piece; Respectively drawing a stratum distribution map, a lithology distribution map and a topography map of the geological period t according to the underburden stratum, the underburden lithology and the elevation data of the top surface of the underburden stratum of each drilling hole in the geological period t extracted in the step (2); step (4), restoring the paleo-hydrodynamic condition; According to the t-time stratum distribution map, lithology distribution map and topography map drawn in the step (3), the stratum, lithology spreading and surface relief conditions are synthesized, the map piece containing stratum, structure and topography elements is used as a base map to draw an ancient hydrodynamic environment map, the runoff direction and the watershed of surface water and underground water are approximately drawn, ancient rivers and ancient lakes are presumably drawn, a secondary hydrodynamic unit is defined, the supply area and the drainage area of a prospecting target stratum are defined, and the current ancient hydrodynamic environment is recovered.

Description

Method for recovering palaeodynamic conditions of sedimentary basin Technical Field The invention belongs to the technical field of sedimentary basin uranium ore exploration, and particularly relates to a method for recovering palaeodynamic conditions of a sedimentary basin. Background The research of the palaeodynamic conditions of the sedimentary basin has important significance for the exploration of sandstone uranium ores, because sandstone uranium deposits are water-formed uranium deposits, groundwater is used as a carrier for uranium element migration, and the hydrodynamic conditions control elements such as the migration direction, the migration speed, the migration distance and the like of fluids such as oxygen-containing uranium-containing water, oil-gas-water and the like. Therefore, the distribution and evolution characteristics of the groundwater ancient hydrodynamic field play an important role in controlling the formation and distribution of sandstone uranium deposits. The method has the advantage that the method can play a guiding role in sandstone-type uranium ore exploration through restoring the palaeotechnical geological conditions of the basin. The method for recovering the paleo-hydrodynamic conditions is more, the paleo-hydrodynamic conditions in the deposition period can be recovered approximately according to the layer type, the granularity and fineness of the sediment, the thickness of the stratum and the like in the deposition period, and the paleo-hydrodynamic conditions after the deposition period are recovered mainly according to the change of the fluid potential. The concept of fluid potential was first proposed by Hubbert (1954), and later Toth (1962) proposed the concept of "hydrodynamic field" and established a new theory of gravity through-the-layer flow and hydrocarbon transport and accumulation relationship, combining the distribution, evolution and fluid transport and accumulation of basin hydrodynamic field, and basin hydrodynamic numerical simulation became the main means of hydrodynamic condition research with recent basin analysis quantification research and development of basin simulation technology (Wang Zhenliang, 2007). The palaeodynamic conditions recovered by the method have certain guiding significance for the exploration of sandstone-type uranium deposit, but the palaeodynamic conditions for recovering the main ore-forming period of the uranium deposit still have defects, and the comprehensive complement-diameter-row conditions of regional strata cannot be indicated. Sandstone-type uranium deposit has the characteristic of staged 'curtain' -type ore formation, the main influencing factor of ore formation is the construction activity, the uranium ore formation period is often within millions of years after the strong construction lifting activity, each lifting of stratum enables the hydrodynamic condition of groundwater to be changed or activated again, and the uranium ore formation effect is developed. According to the relation between the age of uranium ores and the construction activities of the existing sedimentary basin in China, the large-scale construction activities of most basins are not cultivated after the uranium ores are formed in the last period of uranium ores, the paleo-topography and paleo-hydrodynamic conditions of the uranium ores in the last period of uranium ores can be considered to be inherited by modern times with a large probability, so that the characteristics of paleo-topography, stratum distribution, lithology distribution and the like of the uranium ores in the last period of uranium ores are ascertained, the runoff direction of surface water and groundwater at the moment, the groundwater supply and drainage area and the groundwater watershed of the mineral bearing destination layer can be directly recovered, and the distribution situation of paleo-rivers and catchment areas is approximately presumed. Disclosure of Invention According to the underground hydrodynamic law, the invention provides a method for recovering the paleo-hydrodynamic conditions of a sedimentary basin, and the paleo-topography map, paleo-geomap, lithology distribution map and the like of the last uranium ore formation period are compiled through a drilling database based on the research of the structural evolution and the uranium ore formation age relationship. The invention adopts the technical scheme that: a method for restoring paleo-hydrodynamic conditions of a sedimentary basin, comprising the steps of: the method comprises the steps of determining a research area structure evolution process and uranium ore formation period, extracting drilling data, drawing a drawing, and recovering an archaic hydrodynamic condition. The step 1 specifically comprises The method comprises the steps of 1.1 of determining a construction evolution process of a research area, 1.2 of determining the ore formation period of uranium, and 1.3 of determining the formation year t o