X-ray Fluorescence Debris Recognition Technology Research

During drilling operations it is essential to acquire lithologic informatioin which is needed to establish formation top, evaluate reservoir, predict formations to be penetrated, and guarantee normal performance of drilling operations. However, due to use of PDC bits and air drilling technique, accurate lithologic identification is difficult to obtain through conventional mudlogging. Geosteering technique also requires even more accurate lithologic identification and formation description.X-ray fluorescence can be utilized to analyze elements of rock samples both qualitatively and quantitatively. On the basis of analysis about upper Paleozoic deposition in north of Eldos Basin, the combination of elements was determined by the X-ray fluorescence technique, which includes Mg, Al, Si, Ca, Fe, Mn, Cl, S, Ti, P, and Ba. The above elements take up 99.48% of total earth crust element contents, and thus can be regard of being representative. The elements can basically reflect the indicating elements existed in petroleum formations. In this paper, about 2000 rock samples from 26 wells located in Tabamiao block of Eldos Basin were analyzed with X-ray fluorescence, and insight investigation was conducted to the analysis result. It is found that a strong correlation exists between element content variation and lithology, and X-ray fluorescence analysis technique can be used as a new means for lithologic identification and formation description, and the qualitative element data can provide technical support for quantitative interpretation and evaluation about lithology, physical property, and formation.The calibration of X-ray fluorescence mudlogging instrument was performed with a great deal of lab tests and LWD, and X-ray fluorescence mudlogging process was established. Lithological identification and interpretation method was proposed through detailed study, which had been extensively applied in south of Eldos Basin, Tarim Basin, Erlian Basin, and Bohai Bay Basin. Gradual improvement was made throught application. It has been developed into a mature LWD technique which can be used to determine lithology, describe formation and provide guidance for drilling operations.It is proven that X-ray fluorescence technique is quite feasible to be used in LWD. The element content data obtained from such a technique can provide technical support for accurate lithologic identification and formation determination. The long-term mudlogging problems encountered while using PDC bits and air drilling technique can be solved. Moreover, it may be found through future further research that X-ray fluorescence technique can be used for reservoir evaluation, reservoir fluid identification, and sedimentary facies study. X-ray fluorescence technique is a solid step forward towards "qualitative" mudlogging technology.