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The Study of Fractured Rock Permeability in Huangdao Water Sealed Underground Oil Tank

Author: MaFeng
Tutor: ChenGang
School: China University of Geosciences
Course: Groundwater Science and Engineering
Keywords: Permeability tensor Network Simulation Discrete fracture Fracture seepage
CLC: P641
Type: Master's thesis
Year: 2010
Downloads: 193
Quote: 3
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Abstract

In Huangdao the groundwater closure petroleum storage caverns located in Huangdao District, Qingdao City, Shandong Province, China in the construction of the first large-scale national strategic oil reserve pool, hole database design capacity of 300 × 104m3. Huangdao water sealed oil storage caverns engineering project relies on the fracture distribution and causes permeability analysis, discrete fracture network simulation analysis and discrete fracture connectivity, four aspects more in-depth studies. Low permeability fractured media is the ideal location for the area of ??oil storage caverns. Fractured media as a Petroleum Occurrence body, its spatial structure and basic hydraulic parameters for subsequent fracture water seepage simulation and water seal Evaluation the key hydrogeological data. The lithology of the study area for the Proterozoic granite gneiss dark lamprophyre dykes. The rock mass is subjected to long geological history of the evolution of the long-term effect of the tectonic stress field of different sizes and in different directions. This led to the randomness of the distribution of the rock mass structure, morphological diversity and complexity of the combination of space, so that the study of the rock mass structure becomes very complex. Statistical significance in terms of the large number of fractures, it was found that the cracks in the rock with a certain regularity, and control by regional tectonic movement. Therefore, the identification of tectonic movements in the study area, the fracture surface network simulation, and establish the basis of fracture seepage model. Network simulation of the surface structure according to the measurements obtained at the scene and a variety of geometric parameters of the probability distribution to generate obey these distribution structure of the regular surface network geometry, that is based on the geometric parameters of the limited natural outcrop or artificial the excavation surface structure surface Deriving rock the structural parameters of the body within the distribution, realize that this process is usually used in the Monte-Carlo method. Seepage research as an important scientific and engineering applications, more and more apparent with the development of many application disciplines and significant practical engineering problems need to be resolved, the majority of the attention of scholars. The study involved many fields, such as geotechnical engineering, water conservancy and hydropower engineering, petroleum engineering, and rock mass underground structures construction projects. Of this thesis is to analyze the percolation characteristics of the study area, both from the fissure permeability tensor, and the fracture network connectivity. Permeability tensor is characterized by the fracture permeability basic parameters, which is a direction of both size amount, expressed mathematically by the matrix. In this study, according to the the field surface fissures statistics and the statistical results of the drilling fissures, combined with three-dimensional permeability tensor theory to strike a study area, the permeability tensor permeability tensor correction according to water pressure test results, and finally obtained the study area on the plane and the vertical variation of penetration tensor. Fractured connectivity analysis based on the fracture network simulation. Consider fractured Connectivity is bound to be cognizant of the regional fracture gap width, trace length and hydraulic conductivity. These parameters can be derived through the surface structure surface survey and drilling fractured statistical analysis. Connectivity area is actually determined according to the results of the fracture network simulation an effective impermeable boundary, all connectivity within the fractured hydraulic connection exists, a different area of ??connectivity, the fissures not directly conducting. Connectivity analysis of algorithms is based on the logical relationship of mutual cutting fissure. Huangdao water sealed oil storage caverns on the basis of the above theories and research methods, mainly for the following three areas of research: 1. Fissure Causes and Developmental Laws of this paper, the fault causes and tectonic movement theory analysis that the regional distribution of the joints characterized by the Yanshanian Pacific plate subduction to the NW or W, and experienced a complex tectonic movement of the the Yanshan early, middle and late. According to the study observed, the distribution of the rock mass and fault mutual cutting relationships, the studies suggest that the formation of the whole of the study area and its periphery fault is the result of the violent activities in the Yanshanian Pacific plate, the complex nature of the fault activity, has experienced more than term nature of the conversion, the Yanshan early, area by NNW direction compressive stress, the study area is mainly fracture formation (including F3, F4), while secondary NE joints extend to NW; Yanshan mid-pulled gravitational environment , upwelling of magma, dyke formation; late Yanshanian - today, the overall study area by the compression of the Pacific Plate to the W, F3 presents a twist of the nature of the right line pressure, F4 is presented to left-twisted nature study area, West The side part fissures extension under tensile stress, gap width becomes larger. The variation of the permeability tensor (1) through the the hydrogeological study area test and Geophysical results, preliminary analysis of the study area, the plane and the vertical permeability variation, to evaluate the permeability of different scales. (2) the importance of the fractured rock mass permeability coefficient and difficult uncertainty, the paper uses new technology can be drawn not only on the level of penetration of the main values ??of the variation, and obtained the penetration of the vertical direction of the main value and penetration changes in the law. For practical engineering data and more calculated tedious this feature in Excel prepared calculated penetration principal value and tendency, inclination VB program, you can easily get a large number of different depths permeability tensor. Analyzes, the permeability tensor changes in the plane of the hole reservoir area and fissure occurrence changes consistent; vertical permeability of the size of the gap width changes are basically the same. (3) by drilling imaging statistics derived permeability tensor, by the software to recognize the effect of microfractures gap width read a certain amount of human error, so the derived permeation main value has a certain deviation, but can be reflect the penetration of the variation of the principal value. Relatively accurate estimate for this deficiency by software to identify the minimum image pixel. The same time, at different depths through the water pressure test of the permeability tensor correction method. Correction factor of 0.07 to 0.89 obtained in this study correspond to different depths correction, the magnitude of the penetration of the main values ??and water pressure test consistent with the direction of the main infiltration unchanged. Fracture network simulation and seepage study (1) In this paper, given various parameters of the fractured probability of the statistical distribution of the type and distribution parameters based on the hole reservoir area of ??the smaller range of the two-dimensional structure of the surface network simulation from the different profiles the development of cracks, the the profile density map of the joints and RQD Figure. The results show that the storage caverns I major distribution has a fractured group, vertical-30m occurrence at larger fracture density is less than 1 / m the RQD distributed between 70 to 90%; storage caverns the region Ⅱ mainly developed two sets of nearly orthogonal cracks, fracture density is less than 0.5 / m RQD of 90%, compared to the region Ⅰ less fractured and weak, the overall permeability. (2) to do a three-dimensional network simulation of the entire study area in the case of considering the development of faults and fracture network maps of the study area, the gap width distribution, storage coefficient maps, fractured connectivity zone map and drilling connectivity Area Plans. Discrete fracture seepage characteristics, connectivity analysis of the entire study area, the South Orient to the direction that the entire analog connectivity area. ZK13 and ZK15 drilling connectivity analysis to simulate the impact of water levels in boreholes fissures range.

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CLC: > Astronomy,Earth Sciences > Geology > Hydrogeology and Engineering Geology > Hydrogeology (groundwater hydrology )
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