The Research On Date Processing And Interpretation Methods Of Electromagnetic Wave MWD

In recent years, with the development of world economy, the world of oil and gasdemand is increasing year by year, but oil exploration and exploitation industry has beenturned to develop the small-scale, thin reservoir and the reservoir of poor physical properties.At this time because of its function of geosteering, LWD not only can provide real-timeinformation of the formation, but also the date can reflect the real parameters and the dataaccuracy is higher, so become an advanced logging technology developing rapidly in recentyears, which are widely used in high angle wells and horizontal wells of geosteering job,especially in offshore drilling more highlights its advantages. As one of the core part of LWD,drilling electromagnetic wave resistivity logging can simultaneously measure not only theformation resistivity and dielectric constant, also apply to all kinds of conductive andnon-conductive medium. Abroad, the electromagnetic wave LWD applications has been verywidely, and the technology is quite mature. although our country have done a lot of work ontheoretical methods, instrument design, and data processing in the electromagnetic waveLWD resistivity measurement, until now can really use to the scene of the logging instrumentis also very less. Therefore, the electromagnetic wave logging while drilling technology toexpand further research is necessary.Electromagnetic wave resistivity LWD though relative to the conventional wirelinelogging has many advantages, but because of the complexity of the actual loggingenvironment, logging response are influenced by environmental factors, such as theeccentricity of the instrument, the influence of surrounding rock, mud invasion influence,affects of borehole, formation anisotropy and the influence of the relative angle between theinstrument and layer, etc. Traditional environmental impact factor correction is mainly basedon the classical chart interpretation, so workload is big and inefficient. Article on the basis ofthe derivation of the electromagnetic wave resistivity LWD of the dyadic Green’s function,use the forward modeling algorithm for the electromagnetic wave LWD environmental effectfactors in the system analysis. On this basis, according to Schlumberger ARC675instruments,made the corresponding logging interpretation of the classic chart, curve chart for the further data fitting, provide a feasible method to achieve the computer automatic correction oflogging data. Finally, we derived the electromagnetic wave LWD the geometric factor,combination of jacobi matrix and the least squares algorithm for intrusion model wasnumerical iterative inversion calculation, the performances of invasion radius, invasion zoneresistivity and virgin zone resistivity three arguments. The dyadic Green’s function in thispaper, and automatic computer logging data correction method and the three parametersinvasive strata iterative inversion method, have provided theoretical guidance forelectromagnetic wave LWD equipment research and development as well as data processing,at the same time provided a reliable guarantee for logging data processing and interpretationsoftware development.