负向构造塌陷体的地震正演模拟——以塔河油田为例  

SEISMIC FORWARD MODELING FOR COLLAPSE BODY IN NEGATIVE STRUCTURES

作　　者：何成江[1,2] 张慧涛[2] 

机构地区：[1]西南石油大学 [2]中国石化西北油田分公司勘探开发研究院

出　　处：《天然气勘探与开发》2016年第3期21-24,40,共5页Natural Gas Exploration and Development

摘　　要：位于塔里木盆地沙雅隆起阿克库勒凸起西南部的塔河油田的外扩评价揭示了负向构造区也存在油气富集区,而在地震处理与解释上,负向构造塌陷体的缝洞成像与识别难度大。通过建立垮塌岩溶储层空间分布的地质构造模型,并利用全波场交错网格差分算法开展正演模拟研究。结果表明,负向构造岩溶塌陷在正演地震剖面上的反射具有表层"下凹"、内幕串珠状及同相轴"短小"的特征,与围岩特征存在着明显的差异,与塌陷体实际的地震剖面吻合度较高;利用叠前深度偏移能够更加准确地对溶洞塌陷形成的强反射进行归位,可较为准确地成像地下岩溶系统,通过正演地震成果可指导负向构造塌陷体的识别,对进一步开展岩溶塌陷体识别与刻画具有重要意义。Tahe oilfield is located in southwestern Akekule uplift of Shaya highland, Tarim Basin. Its out-stepping evaluation indicates that there exist some oil and gas accumulation areas in negative structures. However, on the part of seismic processing and interpretation, it's difficult to carry out the fracture-cave imaging and identifying of collapse body in these structures. In this paper, based on a geological structure model established for reservoir-space distribution of collapsed karst, forward modeling is studied by using the full-wave-field staggered grid difference algorithm. Result shows that the reflection of karst collapse on forward seismic profile is featured by depressed surface, beaded inside, and short event, which is quite different from that of surrounding rocks and highly consistent with the actual situation. By prestack depth migration, the strong reflection formed by karst collapse can be regressed accurately, so as to image subsurface karst system. The forward seismic modeling may provide guidance for identifying the collapse body, and will be of great significance in the further identification of karst collapse body.

关 键 词：负向构造 塌陷体 全波场交错网格差分算法 地质模型 正演模拟 地震反射 塔里木盆地 塔河油田 

分 类 号：P618.13[天文地球—矿床学] P631.4[天文地球—地质学]