利用测井资料识别重力流沉积及意义

Recognition of gravity flow deposits with log data and its implications

突发性重力流沉积以厚度小、类型多、致密坚硬并夹杂于正常沉积之中为特点,致使利用常规测井资料识别地层岩性和流体性质难度较大。W油田流一段是重要含油层系,通过岩心观察,发现重力流沉积非常发育,且类型多样。在对其沉积特征进行分析的基础上,基于高精度地面岩心扫描的自然伽马和密度测井曲线,提出了利用交会图法和测井曲线形态法有效区分重力流沉积与正常砂泥岩沉积的方法。最后在对重力流沉积的含油性和物性进行评价后,认为远端浊积岩是有利的勘探开发目标,指出了2个可能的含油深水浊积砂体,为该油田进一步评价挖潜提供了依据。

The deposits of sudden event gravity flow which are not only rigid and compact but also have characteristics of thin thickness and complex sedimentation type are generally mingled with normal deposits,which makes the recognition of lithology and fluid property very difficult with conventional log data.According to core observation,it is considered that the first member of Liushagang Formation in W oilfield which is the important oil-bearing series developed large amount of various types of gravity flow deposits.Based on the analysis of depositional characteristics,the methods of crossplot and logging curve shape are proposed to distinguish effectively the the event gravity flow deposits from the normal deposits by using the high precision gamma ray and density curve of subaerial core scanning.Finally the oil possibility and physical property of the gravity flow deposits are evaluated,and the result shows that distal turbidite is the favorable exploration and development target and two possible oil-bearing turbidite sand bodies are pointed out,which provides basis and supports for further evaluation and tapping the potential of the oilfield.