Studying shallow low-velocity zone using electric data
Zheng Li1, Xu Jianhua1, Kang Suwei2, Wang Caifu1, Xu Shichao1, Hao Shujuan1
1. Non Seismic Exploration Department,BGP Inc.,CNPC,Zhuozhou,Hebei 072751,China;
2. The Third Geological Engineering Investigation in Shanxi,Jin Zhong,Shanxi 030620,China
Abstract：Geology condition of the earth surface is extremely complicated in Y ingxiongling area in Qaidam Basin. Velocity and thickness of low-velocity zones are quite different from one place to the others,which cause statics problems for seismic exploration. Using magnetotelluric sounding (MT) data acquired in Youshashan and high frequency electromagnetic sounding (AMT) data acquired in Gan-chaigou, we study shallow low-velocity zones in order to find out its thickness and velocity variation trend. Low-velocity zone thickness and its disti bution are determined by the relationship between shallow high-resistivity layers and shallow low-ve-locity layers. Velocity variation of low-velocity zones is determined using our improved Faust experience formula and litting parameters. Our electric data results are consistent with uphole data and LVL data, which can be used for static corrections and velocity model building.
