Research And Application Of High Accurate Reservoir Inversion Technique And Gas Detection Method

The main task of seismic and oil-gas detection is to develop seismic wave impedance inversion with much data and many restricted conditions, improve data utilization and inversion accuracy and recognize slight layer precisely, what's more, to detect the gas which may be stored underground using seismic frequency spectrum property, realize the prediction and characteristic of reservoir and provide the proof for blocking out the range of profitability.In order to improve the inversion accuracy, this paper will process the poststacked data with mathematical analysis method of wavelet separate frequency dividing the seismic data to a series of seismic sections which have narrow band with central frequency(wavelet separate frequency section) and then use"separate frequency processing along the layer"and ination gamma ray neutron laterolog etc to acoustic travel time curve."Modulation"is a restricted condition of acoustic curve, which could improve inversion resolution and offer the inversion result geology meaning. To improve the resolution and stability of non-linear inversion, we will increase the higher order of Tailor Series based on non-linear optimization in inversion theory and find the solution to positive definite matrix to improve inversion resolution and use forced positive matrix to improve inversion stability. During the practical inversion of isolated field Nanqudong and Xinliyouquansiduan, we have predicted the distribution of fluvial faces with pure sand body and provide the scientific references for the arrangement of well position of reservoir rolling seismic prospecting.In the gas detection of reservoir, we propose the seismic frequency spectrum should be calculated through the intended zone of overlying and underlying strata which would probably have gas. This breaks the tradition including the frequency spectrum calculation method of sliding time window of intended zone, so the intended zone could be restricted in a very tiny time window more accurately to make the result of gas detection and intended zone better correlated. This method could be used as gas detection in Xinduqitiansuiningzu and Chuanbeiyanan. The coincidence rate with given well and detected well is more than 80% and the detection result could give instructions to the seismic exploitation of oil-gas field.