简介：本文计算了地面磁电阻率法在监测地下水体中垃圾渗漏液运移的动态磁电阻率异常。基于对垃圾场地概念模型的水文地质仿真,建立了数值地电模型,并采用改进的有限差分软件MMR2DFD,分别计算了点源,MMR-TE方式,MMR-TM方式下半空间模型以及断层模型的磁电阻率异常响应。半空间模型的正演结果表明,垂直于主要电流方向的磁场分量包含更多地下异常信息,MMR-TE模式能有效进行地下水污染监测。断层模型的计算结果更进一步验证了MMR在地下水污染物运移监测中的有效性。

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：Anewmulti-moderesistivityimagingsonde,withtoroidalcoilsassource,canconductthreeresistivitymeasurements:azimuthalresistivity,lateralresistivity,andbitresistivitymeasurements.Thus,theloggingtimeandcostaregreatlysaved.Thetoroidalcoilsaresimplifiedasanextendedvoltagedipoleandtheresponseequationsarederivedforahomogenousformation.Basedon3DFEM,thedepthofinvestigation(DOI),verticalresolution,circumferentialazimuthalcapacity,boreholediameter,mudresistivity,thicknessoftargetformation,andtheresistivityofthesurroundingformationandmudinvasionaresimulated.TheresultssuggestthatthethreemeasurementmodesofthenewsondearedifferentinverticalresolutionsandDOIs.Thecircumferentialdetectionabilityoftheazimuthbuttondependsonthecontrastbetweentheanomalyandformationresistivityandtheopenangleoftheanomaly.Whethertheboreholeistruncatedatthebitornothasagreatinfluenceonthesimulationresults.Theboreholeandmudinvasionaffecttheapparentresistivityinallmodes,buttheeffectsofresistivityofsurroundingformationandthicknessofthetargetformationareonlycorrectedforlateralresistivitymeasurement.