Approximate Interpretation of 3-D Data Using 2-D Inversion Program in the DC Resistivity Sounding
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摘要: 直流电阻率测深剖面数据解释最好的方法是二维反演, 这是由于它反演速度快, 而三维反演则需要很多的实测数据、很长的计算时间.而且通过对几种三维模型测深数据的二维反演结果的研究, 发现尽管对无走向的良导矿体, 二维反演方法所圈定的异常中心与真实矿体中心有一定的误差, 但基本上还是能反映矿体的真实形态和中心位置.当矿体具有一定的走向长度时, 则无论对高阻矿体还是良导矿体二维反演的效果都很好.Abstract: The 2-D inversion is the best method in the interpretation of DC resistivity sounding profiles data owing to its high speed, but the 3-D inversion, by contrast, needs more measured data and more computer time. Through the 2-D inversional study of several 3-D models, we know that for the good conductor ore-body without strike, there is some deflection between the center of real ore-body and the center of anomaly enclosed by the 2-D inversion, however, the anomaly can still reflect the true shape and the center position of the ore-body in the main. When the ore-body has certain lengths in strike, the effect of 2-D inversion is good to it, no matter its resistivity is high or low.
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Key words:
- DC resistivity sounding /
- 2-D inversion /
- 3-D model /
- approximate interpretation
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图 2 模型1的平面图(a)及剖面图(b)
Fig. 2. The x-y plane view (a) and the x-z cross section view (b) of the model 1
图 3 模型2和模型3的平面图(a)及剖面图(b)
(a) 围岩电阻率ρ0=50 Ω·m, 矿体电阻率ρ1=100 Ω·m; (b) 围岩电阻率ρ0=100 Ω·m, 矿体电阻率ρ1=50 Ω·m
Fig. 3. Plane views (a) and section views (b) of the model 2 and model 3
图 4 模型1偶极—偶极测深反演断面等值线(等值线单位Ω·m)
Fig. 4. Cross section contours of pole-pole sounding inversion for the model 1
图 5 模型1偶极—偶极测深反演平面等值线(等值线单位Ω·m)
Fig. 5. Horizontal section contours of pole-pole sounding inversion for the model 1
图 6 不同延深的高阻矿体主剖面视电阻率反演断面等值线(等值线单位Ω·m)
a.矿体体积4 m×10 m×4 m; b.矿体体积4 m×8 m×4 m; c.矿体体积4 m×6 m×4 m; d.矿体体积4 m×4 m×4 m
Fig. 6. Contours of apparent resistivity inversion in main profiles of high resistivity ore-bodies with different strike lengths
图 7 不同延深的低阻矿体主剖面视电阻率反演断面等值线(等值线单位Ω·m)
a.矿体体积4 m×4 m×4 m; b.矿体体积4 m×6 m×4 m; c.矿体体积4 m×8 m×4 m; d.矿体体积4 m×10 m×4 m
Fig. 7. Contours of apparent resistivity inversion in main profiles of low resistivity ore-bodies with different strike lengths
表 1 有限单元网格间距
Table 1. Mesh intervals of finite element
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