A Study On The Capacity Measurement Techniques For The Large Oil Storage Caves

Ground vertical metal tanks are widely used as a common way for oilreserves in China. Ground tanks are easily attacked in war time, and suffer from fire,lightning strike. Therefore, underground storage method receives highlyconsiderations in the national strategic oil reserve projects. Due to its advantages ofeasy management, good safety, and reliability, this method will be the main approachfor future oil reserves. In this work, capacity measurement techniques for an oilstorage cave are studied with a purpose to provide technical support for large cavernstorage engineering.In the thesis, capacity measurement techniques for an oil storage cavern aredescribed, including sonar, photogrammetry and electro-optical distance-rangemethods. The measurement principle, accuracy and features are elaboratedrespectively. Furthermore, a new method suitable for underground water seal oilcavern capacity measurement, i.e. three-dimensional laser scanning method, is putforward. The working principle and applications of the3-D laser scanner method aredescribesd. Experiments are carried out on the scanner accuracy calibration, andfound that the distance, angle and point precision are within±2.5mm、0.0044°and3mm respectively. Data acquisition and processing theory and method for the3-Dlaser scanner measurement are investigated. In the process of data acquisition, thecavern wall is scanned with a3-D laser scanner to obtain the point cloud data. Beforedata acquisition, one should emplace consisting of sites and target plates, and setparameters of the scanner. Data processing can be divided into two parts, point clouddata preprocessing and volume calculation. The integrated3-D point cloud data isgot by means of registrating and denoising the original data. In the calculation,integral thought is applied. The point cloud is divided into several prisms. The totalvolume and volume table can be calculated based on Dthe integration of triangle area and Dthe superposition of prismoid volume. The measuring method for large space volume with a3-D laser scanner isverified by experiments. Experiments were carried out on the vertical metal tanks,rooms and cave tunnel. The room and the tunnel were also measured manually with aruler and a laser range finder. Comparing the results received by3-D laser scannerand national standard method, the relative deviation of volume table is within0.26‰.The relative deviation between the new laser method and manual measurement iswithin2‰and1.5‰, which means that the3-D laser scanner method is feasible inthe cave volume measurement. The measurement uncertainty of three dimensionallaser scanning measurement system in the cave volume measurement is less than0.63‰, which is obtained by evaluating the measurement uncertainty of scanner andcalculation method.