【摘要】 川中须家河组及雷口坡组气藏分别属于致密砂岩油气藏及碳酸盐岩气藏。致密砂岩储层因低孔隙性和含油气饱和度变化所产生的地球物理特征相对变化微弱,储层和气层预测是地震预测难点;碳酸盐岩成岩作用比较复杂,速度、密度和孔隙度相关较差,储层物性定量预测难度较大。通过四川盆地大川中地区简阳—大足区块叠前地震资料处理和储层预测,本次攻关取得了如下主要成果:①分析了影响地震资料保幅处理的主要因素,提出了地震叠前保幅处理的关键技术,形成了有效的保幅处理流程;②典型井致密砂岩的岩石物理分析表明:弹性阻抗和纵横速度比有效区分岩性,纵波速度、横波速度和孔隙度相关较好,有效预测物性,储层预测思路是先区分岩性,后区分物性;③提出了弹性阻抗系数技术预测致密砂岩气层,基于储层特征参数约束下地震技术定量预测碳酸盐岩储层新方法。更多还原

【Abstract】 The natural gas reservoir of Xujiahe Formation and Leikoupo Formation in Jianyang-Dazu field of middle Sichuan Basin belong to tight sandstone gas reservoir and carbonate gas reservoir respectively. The variation of geophysical characteristics of tight sandstone gas reservoir is relatively small, due to low porosity and change of hydrocarbon saturation. So the main challenge for seismic prediction is to predict reservoir and gas strata. Diagenesis of carbonate rocks is so complex that the connection among velocity, density, and porosity is bad, thus it is difficult to predict physical properties of the target reservoir quantitatively. Through prestack seismic data processing and reservoir prediction in Jianyang-Dazu field, following results have been obtained. Firstly, primary factors affecting amplitude-preserved processing of seismic data are analyzed, key techniques for prestack processing are developed, and an effective flow is finally formed. Secondly, petrophysical analysis of typical tight sandstone indicates that elastic impedance (EI) and P-wave-to-S-wave velocity ratio could differentiate lithology effectively; the correlation between P-wave and S-wave as well as porosity is so good that it could be used to predict physical properties. Therefore physical properties are differentiated later than lithology. Thirdly, elastic-impedance coefficient (EC) is developed to predict gas strata in tight sandstone, and new technique to quantitatively predict carbonate reservoir based on seismic techniques constrained by typical reservoir characterization parameters is also presented.更多还原