In-situ measurement and analysis of pores are helpful to understand the properties of rocks. However, continuous quantitative analysis of pores in whole borehole is still difficult. Borehole camera technology can capture the borehole wall image of the whole well section by going deep into the borehole, which provides technical conditions for the measurement and analysis of pores. In this paper, a continuous measurement method of rock pores based on borehole camera technology is introduced. According to the characteristics of the optical image of borehole wall, a method of pore recognition and analysis is proposed. Specifically, the influence of redundant information on pore recognition is eliminated, and then the pores are accurately recognized by binarization and morphological operation. Based on the results of pore recognition and the coordinate information provided by borehole wall image, the calculation methods of surface porosity and line porosity are proposed, and the statistical analysis of pore distribution is realized according to the calculation results. In addition, the morphological characteristics of pores are also discussed. This method realizes the accurate recognition and quantitative calculation of pore structure based on borehole wall image, and provides a new method for continuous analysis of pore structure in the whole well.
Han, Z.; Wang, C.; Hu, S., and Wang, Y., 2018. Application of borehole camera technology in fractured rock mass investigation of a submarine tunnel. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 609–614. Coconut Creek (Florida), ISSN 0749-0208.Borehole camera technology can penetrate into the inner part of the rock mass, observe the characteristics of the fracture, measure the data of the fracture geometric parameters, and a reasonable statistical method is the key to analysis of structural characteristics of fractured rock mass. Based on the observation results of digital borehole camera technology, the principle and method of calculating the fracture parameters from borehole images are described. Taking the Qingdao Jiaozhou Bay Subsea Tunnel Drilling ZK3 as an example, the structure information revealed by borehole is obtained by borehole camera. The statistical analysis of geometry parameters is studied and the distribution of fracture is analyzed, including the dominant occurrence of calculation, aperture distribution and depth distribution etc.. The integrity index RWID of the borehole wall rock mass is established, and the integrity of the wall rock mass is evaluated according to this index. The main conclusions are as follows: (1) digital borehole camera technology provides an effective technical means for geological survey of fractured rock mass; (2) the evaluation index of RWID based on borehole wall integrity core length can reflect the integrity of rock mass, providing a good verification method for RQD method.
The pore network in reef limestone provides an important resource for fluid storage and flow. Three-dimensional (3D) reconstruction and characterization of the spatial structure of reef limestone pores offers a valuable way of identifying its physical and mechanical properties. This paper reports on a study where optical and acoustic microscope images were used to combine the advantages of the high resolution of optical testing with the high penetration capabilities of acoustic testing. This overcomes existing problems with multi-scale structural imaging of the pores in reef limestone caused by the small penetration depth of traditional optical imaging and the low resolution of ultrasonic imaging. First of all, a correlation function between the shallow and deep pore structure of reef limestone is established. This draws on high-resolution data from shallow optical microscopic images and deep acoustic microscopic images with a multi-layered cross-section. The contours of the shallow and deep pore structure are then digitized. After this, horizontal section control points and vertical transition contours are constructed that enable a deep integration of information about the multi-dimensional geometric morphology of the pore structure to be realized, providing in turn for a fine-grained 3D reconstruction of the pore structure at different scales. Finally, factors governing the characterization of contour similarity and center deviation are proposed that make it possible to generate spatial representations of the pore structure across multiple dimensions. A real-world case analysis is then used to verify the feasibility and reliability of the proposed method. The results show that the method can provide abundant data for the establishment of a reef limestone pore network and physical model, making it possible to improve the quality of 3D reconstructions of the pore structure and improve the 3D imaging of reef limestone pore networks. The proposed method can underpin new approaches to analysis of the pore structure of reef limestone and support a wide range of potential applications in the field of pore visualization and characterization.
Given the single and one-sided problems of traditional rock mass structure integrity evaluation methods, this paper will use borehole test data that were obtained by conventional logging methods to extract the key geological data that will be used for integrity evaluation from digital images and digital signals. Based on a comprehensive method of multivariate data analysis, an evaluation method for rock mass structure integrity will be established, which reflects the differences in rock mass structure, rock mass fragmentation, and rock acoustic response. The rock mass combination function [C(h)], rock mass fragmentation function [F(h)], and sound velocity function of a rock mass [U(h)] will be constructed, which could realize the quantitative description of rock mass integrity multiple parameters. Then, the rock mass combination degree, rock mass fragmentation, and rock mass propagation sound velocity parameters will be classified using fuzzy mathematics, and the rock mass structure integrity evaluation index [Mc(h)] based on multivariate data will be constructed. Finally, the method will be combined with practical engineering for verification and analysis. Compared with the traditional evaluation method, the method in this paper considers more factors that affect the stability of rock mass, which combine the degree of rock mass combination, rock mass fragmentation, and rock mass sound velocity. The method in this paper will realize the integrity evaluation of a borehole rock mass structure from different dimensions. Compared with the traditional method, the integrity evaluation results will consider more comprehensive factors.
The automatic recognition of layer paths in the ionogram can get the key parameters of ionogram which are very important and necessary to the research of space exploration. This paper describes a new automatic recognition method and its application to automatically recognize layer paths from ionogram based on morphological operator and inversion technology. This method is verified through the comparison of actual detecting data with statistical analysis. Results show more than 90% automatic recognition results accord with the people analysis. This automatic recognition method has high acceptable rate and is suitable for recognition ionogram with different high angle wave states. It can accurately recognize the parameters in the ionogram with a fast and precise approach. This method meets the real-time requirements of ionosphere sounding detection in practice.
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