应用同位素示踪技术研究油藏剩余油分布规律——以玉门老君庙油田M油藏为例

Application of Isotopic Tracer to Study of Residual Oil Distribution——An example of M pool in Yumen Laojunmiao oilfield

我国最早采用现代技术开采和最早注水开发的玉门老君庙油田,在67年的开发历史中先后采用测井、油藏工程、岩心、数值模拟、水矿化度分析等方法,研究不同开发时期的剩余油分布规律。这些方法各有特点,同时又存在各自的局限性。而同位素示踪技术对注水开发过程中的油水分布关系和剩余油研究针对性更强,其原理为:对注水井注入两种同位素示踪剂,根据对应油井产出示踪剂质量浓度曲线形态的变化,以及两种示踪剂峰值质量浓度产出的时间差,以色谱分离理论与对流扩散理论为基础,应用示踪剂解释软件,进行注采对应关系分析、储集层非均质性参数确定和剩余油饱和度研究。同位素示踪技术在老君庙油田M油藏4252井组的应用,为老油田后期注水开发剩余油研究提供了一种简捷直观的有效方法。

Laojunmiao oilfield in Yumen is the oldest field in China developed with modern technologies and by waterflooding process. Since 1967, several methods such as well logging, reservoir engineering, core analysis, numerical simulation and water salinity analysis have been adopted for study the residual oil distribution in reservoirs in different periods or stages of development. However, the studies have shown that each of these methods has both peculiarity and limitation of its own. It is indicated that isotopic tracer injection is more suitable for revealing in-situ oil-water distribution and residual oil status. The principle of this technique includes that two isotopic tracers are injected into injection wells. The peak concentration change and the time-difference of the tracers produced from opposite oil wells will be shown on their curves. Then, the injection-production relations analysis, the reservoir heterogeneous parameters determination and the residual oil saturation evaluation are conducted using the tracer interpretation software in terms of chromatographic fractionation theory and convection-diffusion theory. Such an isotopic tracer technique has been used to Wellgroup-4252 of M pool in Laojunmiao oilfield. It is indicated that it is a simple, visual and effective method for study of the residual oil distribution in this old oilfield by waterflooding process.