The Study Of Image Analysis Method Based On Digital Optiacal Borehole Imaging

Digital borehole camera is the new method in optical borehole imaging. The digitalpanoramic borehole camera system (DPBCS), describes the fine structure in borehole wall,achieves the international levels both on image & depth resolution and measurementprecision. The present paper gives a brief review of development history of imagingtechnology in well-logging, presents the imaging principle, system design, processingtechnology and images effect of DPBCS. Since the technique of whole-wall imaging wastackled, it becomes necessary that creating a new method of single- and multi-holesanalysis and wall integrity appraisement and combined explanation with other geophysicalmethod. The main progress of test- interpret-analys is divides to four stages: imageacquirement, image processing, images interpretation to borehole-wall image analysis inthispaper.Refinement,summarizationandgeneralizationwiththesub-questionsinthefourstages are carried on, interval analysis, whole wall analysis and multi-holes analysis aremade subsequent, a criterion of assessment from hole to site with wall integrity propertyand combined application method is established at last. The main research work containingsomeaspectsasfollowing:(1) Image acquirement is the core aspect of digital borehole camera. The papersummarizes the image acquirement method with axial panoramic borehole TV (ATV)device. Besides, this paper puts on researchment on depth correction, magnetic declinationand color cast adjustment,and introduces the technology of seamless stitching method andscanline algorithm which adopted to extract lines of pixels from original video tapes,compass azimuth and depth numeric character identification, attitude (orientation, strike,aperture)calculationinDPBCS.(2) The paper introduces the enhancement method in the field of digital imageprocessing and finds that is an effective tool for borehole images enhancement.The methodused in the paper is list as follows: 1. intensity adjustment, 2.equalize based on imagehistogram 3. filters : lowpass, highpass, sharpen, median 4. edge filters: Roberts, Sober,Laplace, Variance. Some tests with borehole-wall images are carried on to determine theeffective imageenhancementmethodforbestquality.(3) Considering the subjectivity on image interpretation, this paper establishes adescriptive and analyzing system for wall image's interpretation based on boreholeaccidents and typical image library from finished projects. This paper puts forwards to anew combined image interpretation method, which uses the complementarity of geologicalsense images and no-geological sense images between the ATV and DPBCS, solves theproblem of interpretation deviation for lack of experience. The generation reason ofborehole accidents like wall collapse, washout, fluid seepage and casing are introducedwith the relation with image interpretation. Also, the boring data and core samples contrastareconsiderdinthemethod.(4) As the most important innovation in this paper, the brand-new concept system ofwall integrity designation (WID) is emerged, which adopt the image area percent in placeof length percent on RQD system. The application of WID on sandstone and limestoneborehole with the comparison among the TCR (Total Core Recovery), RQD and WID leadthe author to the conclusion that WID is not only suitable to quantitative description of...