利用核磁共振和双频电阻率测井评价高矿化度地层水淹层

中原油田原始地层水矿化度很高,注入水矿化度一般低于原始地层水矿化度.根据水驱油岩电实验可知,有的储层水淹后电阻率呈"U"字形变化,其变化规律随注入水和原始地层水的矿化度比值及储层孔隙结构的不同而发生变化,使得电阻率判断储层含油性存在多解性,增加了常规测井资料识别水淹层的难度.核磁共振和双频电阻率测井新技术具有受岩性和矿化度影响小的优势,在水淹层识别上具有独到之处,在一定程度上弥补了常规测井技术的不足.通过实际应用,探讨了核磁共振和双频电阻率测井资料在中原油田高矿化度地层水淹层中的评价方法,取得良好效果,为测井新技术推广应用于水淹层评价起到了借鉴作用.

EVALUATING WATERFLOODED FORMATION WITH HIGH SALINITY WATER BY THE LOGGING TECHNOLOGIES OF NUCLEAR MAGNETIC RESONANCE AND DUAL FREQUENCY RESISTIVITY

The original salinity of formation water is high in Zhongyuan oil field. The salinity of injected water is usually lower than original salinity. Based on the experiment of water displacing oil, the resistivity curve of some reservoirs change in "U" shape after waterflooding. The law of changing is different according to the salinity ratio of injected water to original formation water and pore structure of the reservoir. Thus there are interpretation ambiguity to identify oiliness of the reservoir using resistivity curve, which adding the difficulties of identifying waterflooded formation using conventional logging data. The new logging technologies of Nuclear Magnetic Resonance and Dual Frequency Resistivity have the advantage that they are hardly affected by lithology and salinity. They are unique in identifying waterflooded formation, which somewhat making up the deficiency of conventional logging technology. According to practical application, this paper discusses the methods of evaluating high salinity waterflooded formation in Zhongyuan Oilfield using Nuclear Magnetic Resonance and Dual Frequency Resistivity logging data. The effect is good. The paper can use for reference for the new logging technology application in evaluating waterflooded formation.