Wide field electromagnetic method calculation in arbitrary orientation and its effectiveness analysis

The wide field electromagnetic method E_Ex observation requires the horizontal electrical source (AB) to be parallel measure station (MN), but complex terrain conditions make it difficult meet AB MN in construction, and there is always an azimuthal difference id="m2">α between them, which will bring a large calculation error cause distortion of interpretation parameters if id="m3">E_Ex continues used. In order tackle this problem, we analyse study id="m4">E_Ex derive new id="m5">E_EMN for along ( id="m6">E_EMN ). based on intrinsic relationship electric components id="m7">Ex , id="m8">Ey id="m9">α derives expression id="m10">E_EMN direction, then uses id="m11">E_EMN calculate apparent resistivity. paper, design three-layer geoelectric model angle id="m12">α = 0° id="m13">α 15°wide resistivity parameters, respectively. results show that relative calculated theoretical value less than 1%, verifies correctness validity method. To further verify accuracy method, experimental work id="m14">α was carried out next known well Sichuan. that: firstly, when id="m15">α 1°, 3°, 5°, 10°, 15°, respectively, each frequency point increases with id="m16">α increasing. Secondly, id="m17">α 10% id="m18">EMN used value; thirdly, taking id="m19">α 15° as example, single-station inversions are performed id="m20">Ex id="m21">EMN id="m22">Ex inversion more different from trend logging curve, while id="m23">EMN relatively consistent curve. arbitrary orientation id="m24">EMN proposed paper can effectively reduce influence id="m25">α improve interpretation, also greatly expand applicability flexibility id="m26">Ex areas, has important research practical production significance.