A Novel Video Logging Method based on the Self-Focus Lens Array

Abstract

At present, down-hole video logging method is used to observe the bottom and lateral well wall image, which places video camera on the bottom of logging instrument. This method can acquire the bottom image clearly. It’s difficult to obtain lateral image because optic axis of lenses is placed along with the well axis, and it’s impossible to place an existing camera along the radial direction because of restriction of borehole diameter or pipe diameter and object distance of camera, etc. A method and instrument for acquiring lateral image is presented on this paper, multiple self-focus lenses are placed along radial direction, used special relay lens transmitting the multiple imaging to an image sensor, and formed one image, then transmitted the image to ground. In order to use optic spectral properties, light cone circling the self-focus lenses is used to transfer the image, the minimum overlap radius for measurement boreholethe is analyzed,the seal problem for the optical system is designed.The lateral well wall image is acquired through researching the method of lateral multiple lens, then the phase correction method is used to fuse the image from different angles of lateral well wall. The video well logging instrument is developed using the above method, which can real-timely display the crack opening , filling substance, porosity and rock component of down-hole casing and borehole.So this method can provide an interpretation tools for the pipe internal or downhole phenomena. Key words : Lateral video logging; Image acquisition; Self-focus lens array; Circular light source; Phase correction method; Image fusion