The Color Description For Cuttings Under PDC Bit Conditions

The Color Description for Cuttings under PDC Bit ConditionsIn the traditional cutting logging process, the cutting description was made by the variety of the color and the lithology distinguishing with human eyes. The color of terranes at different age is not similar, and its color keeps same even the cutting is extremely small. And the main colors of different terranes are not same. Therefore, the lithology could be identified by watching the changes of color as the color of stratum is distinct. In the same way, the ratio of the sand to mud would be decided too. So the color is a very important parameter in cutting logging process.As the PDC ( Polycrystallin Diamond Compact ) bit is used widely, the cuttings produced in drilling process are tiny and even distorted due to the mechanism of rock-crushing, hence difficult to be sampled, analyzed, judged and identified. It is also difficult to identify the cuttings and their color through the human's eyes. How to describe the cuttings color under PDC Bit condition has become a problem needed to be solved urgently. The work presented in this thesis is on the purpose of establishing a color description method for cuttings used in logging process.The thesis altogether has six chapters. In chapter one, the methods of color description are introduced. The color histogram is found to be a potential way to describe the cuttings color. In chapter two the correlative knowledge and principle is introduced in detailed. And a brief description of the image acquisition system is given in chapter three. Chapter four and chapter five are author's major work. In chapter four the basic character of cuttings color is studied. Four different kinds of cutting samples are chosen to be analyzed. With a digital camera, the sample images have been taken. The basic character analysis is carried out with programming arithmetic in Matlab. The results have suggested that it is not enough to identify the cuttings color through only getting the distributing of every pixel of cutting picture. HSI color space is more suitable for the cuttings color description, in comparison with RGB color space. It is still in some difficulties to distinguish the cuttings color with the only parameter of hue mean value in HIS color space. It can be seen from the obtained results that the histograms in HSI space can be considered as a potential color description method for cuttings.In chapter five, it is verified if the clustered hue histogram can describe the cuttings color. 13 types of standard cutting samples from Shengli Geological Drilling Company are chosen to be analyzed using the method of clustered hue histogram. The results with average identifying accuracy of 79.2% are obtained, over all the samples analyzed. Among those 13 types of cuttings, 8 types has the identifying accuracy above 80%, and 4 types achieves even 100% identifying accuracy. It is show that the clustered hue histogram tends to be a feasible method to identify the cutting color under the PDC Bit condition.Chapter 6 is the summary of the thesis work. Some suggestions for the future development have also been given in this chapter.