大地电磁法分辨力的模拟分析

Simulation Analysis on Resolution of Magnetotelluric Sounding

对大地电磁测深方法探测油气藏的能力进行了研究,建立了同深度同规模条件下低阻背斜油气藏与高低阻互层背斜油气藏2种不同的储层模型,利用数值模拟的方法,计算这2种模型的大地电磁测深响应,获得理论计算的视电阻率资料并分析2种模型之间的异常差异。数值模拟结果表明,2种模型的理论响应之间存在6%的相对偏差,异常偏差大于实际观测的噪声水平,能被大地电磁观测仪器有效观测到,表明该方法具有比较高的分辨能力,能用于识别不同类型储层的油气藏。

The ability of reservoir exploration using magnetotelluric sounding was studied.The models were established for both high and low resistivity anticlinal reservoirs under conditions of the same depth and same scale.The magnetotelluric sounding response for the models was calculated using by numerical simulation.And apparent resistivity data were obtained and the abnormal difference between both models was analyzed.The result of numerical simulation shows that the two models have a relative difference of 6% in their theoretical response,its abnormal difference is higher than that of observation for noise level,it can be detected by the Magnetotelluric sounder,it is indicated that it has the ability of resolution for distinguishing different oil-gas reservoirs.