玛湖凹陷二叠系上乌尔禾组继三叠系百口泉组之后又发现了一个大型连续型砂砾岩油气藏群.针对该区域成藏特征与成藏模式认识不清的问题.综合利用地质、地球物理以及分析化验等资料,结合区域构造背景与沉积环境,从烃源供给、储盖组合、运移通道及保存条件等4个方面对MH1井区上乌尔禾组油气成藏条件及控制因素进行综合分析.研究表明MH1井区上乌尔禾组砂砾岩油藏连续成藏具有4个有利条件:①二叠系风城组烃源岩具有有机质丰度高、生烃潜量大、双峰式生油特征,为MH1井区上乌尔禾组油藏提供了优质高效的烃源条件;②上乌尔禾组退积型扇体下砂上泥式沉积模式在纵向上形成规模有效的储盖组合;③断层、不整合面和渗透性砂体的三元复合体系共同形成了良好的立体输导网络;④扇三角洲平原亚相致密带、湖相与扇间泥岩以及断裂相互配置,形成复合式多面遮挡,为扇三角洲前缘大面积成藏提供了匹配良好的保存条件.在此基础上构建了 MH1井区扇控大面积成藏模式,并在MH1井区开展了勘探开发一体化部署,获得了规模储量.该研究对下步油气勘探具有一定的指导意义.
准噶尔盆地西北缘中拐凸起东斜坡风城组发育一套遭受风化剥蚀而残留的薄层火山岩地层,该地层内部出现"油水倒置"现象,由于成藏规律认识不清,制约了对该地层的进一步评价.针对该地层岩相、岩性单一,并发育风化壳的地质特征,综合运用岩心、薄片及典型电性识别等方法对风化壳结构进行了识别,识别并划分出土壤层+水解带、淋蚀带、崩解带、母岩4种风化壳结构,根据划分结构建立了风化壳结构组合模式,分析风化壳结构对储、盖组合的控制作用,剖析已发现的油藏.结合岩体发育特征,建立了斜坡薄层火山岩风化壳油藏成藏模式,得到中拐凸起东斜坡薄层火山岩油藏主要发育于构造中低部、风化体结构完整的岩体,有利成藏区环凹陷呈条带状分布的结论.运用该结论指导油藏勘探评价并取得突破,证实了该类地层油气分布规律.研究结果对类似地层的油藏评价具有启示意义.
The finite-difference compensation was applied to the wide angel correction of the elastic screen propagator,and the vector imaging condition was employed through projecting components in the direction of polarization.The information from the elastic wave field could be used efficiently,and the problem of inconsistent polarization of P-SV in imaging was solved.Partial images from different sources could be stacked to generate a final image.The elastic screen propagator with wide angel correction and the vector imaging condition were tested with the model data,which proved the reliability of this method.
In VSP forward modeling with the wave field extrapolation method,we can just simulate upward wave or simulate upward wave and downward wave simultaneously according to the situation,and the multiple wave can be controlled efficiently.In general,under the condition of being only concerned with the primary reflection,we needn't simulate the multiple wave.This method has high efficiency compared with other wave equation modeling methods.In this paper,the split-step Fourier method was used to extrapolate the wave field,which can guarantee the stability of wave extrapolation and the modeling accuracy for the complex model.Model test shows that this method can simulate VSP efficiently and the modeling result is correct and reliable.
