简介:Inthispaper,wetheoreticallyandnumericallystudyacombinedmonopole–dipolemeasurementmodetoshowitscapabilitytoovercometheissuesencounteredinconventionalsingle-wellimaging,i.e.,thelowsignal-to-noiseratioofthereflectionsandazimuthambiguity.First,theazimuthambiguity,whichexistsextensivelyinconventionalsingle-wellimaging,issolvedwithanimprovedimagingprocedureusingcombinedmonopole–dipoleloggingdatainadditiontoconventionalloggingdata.Furthermore,wedemonstratethatthedirectwavespropagatingalongtheboreholeswithstrongenergy,canbeeffectivelyeliminatedwiththeproposedcombinedmonopole–dipolemeasurementmode.Thereflectionsarethereforepredominantinthecombinedmonopole–dipoledataevenbeforethesignalsarefiltered;thus,thereflections’arrivaltimesineachreceiverareidentified,whichmayhelpminimizethedifficultiesinfilteringconventionalloggingdata.Theoptimizedprocessingflowofthecombinedmeasurementmodeloggingimageisgiveninthispaper.Theproposedcombinedmonopole–dipolemeasurementmodemayimprovetheaccuracyofsingle-wellimaging.
简介:初至拾取是起伏地表地震资料处理的关键环节,直接影响近地表建模的精度及静校正效果,但起伏地表资料极低的信噪比使传统的自动初至拾取算法几乎失效,而手动拾取要耗费巨大的人工和时间成本。本文研究了改进超虚干涉法,结合多道多域初至质量监控技术,实现起伏地表资料初至波自动拾取。改进超虚干涉法首次将近地表散射波纳入干涉法提高信噪比的范围,并通过折射波和散射波的线性组合使干涉法适用于起伏地表条件下任意复杂射线路径的初至波类型;提出反向干涉和多域干涉的概念,显著增强了所估计的虚源信号;使用波形反褶积滤波器较好地抑制了干涉导致的"假事件"的形成;采用多道多域初至质量监控技术,实现错误"假事件"初至的自动归位,提高了拾取初至的稳定性。本文研究的初至波自动拾取理论与技术具有突出的鲁棒性和稳定批量处理大量实际三维地震数据的能力,在中国西部山区三维地震勘探数据处理的应用效果显著,质量优于某常用商业软件。
简介:Anewmulti-moderesistivityimagingsonde,withtoroidalcoilsassource,canconductthreeresistivitymeasurements:azimuthalresistivity,lateralresistivity,andbitresistivitymeasurements.Thus,theloggingtimeandcostaregreatlysaved.Thetoroidalcoilsaresimplifiedasanextendedvoltagedipoleandtheresponseequationsarederivedforahomogenousformation.Basedon3DFEM,thedepthofinvestigation(DOI),verticalresolution,circumferentialazimuthalcapacity,boreholediameter,mudresistivity,thicknessoftargetformation,andtheresistivityofthesurroundingformationandmudinvasionaresimulated.TheresultssuggestthatthethreemeasurementmodesofthenewsondearedifferentinverticalresolutionsandDOIs.Thecircumferentialdetectionabilityoftheazimuthbuttondependsonthecontrastbetweentheanomalyandformationresistivityandtheopenangleoftheanomaly.Whethertheboreholeistruncatedatthebitornothasagreatinfluenceonthesimulationresults.Theboreholeandmudinvasionaffecttheapparentresistivityinallmodes,buttheeffectsofresistivityofsurroundingformationandthicknessofthetargetformationareonlycorrectedforlateralresistivitymeasurement.