Identification and Evaluation of Low Resistivity Pay Zones by Well Logs and the Petrophysical Research in China

This paper presents an overview of petrophysical research and exploration achievements of low resistivity pay （LRP） zone by well logs in China. It includes geological characteristics and characteristics of well log response of the low resistivity pay zones discovered and evaluated in recent years, as well as the problems in recognizing and evaluating low resistivity pay zones by well logs. The research areas mainly include the Neogene formations in the Bohai Bay Basin, the Triassic formations in the northern Tarim Basin and the Cretaceous formations in the Junggar Basin, The petrophysical research concerning recognition and evaluation of the low resistivity pays, based on their genetic types, is introduced in this paper.

低电阻率油层研究现状

在详细分析低电阻率油层形成机制的基础上,总结了中外对低电阻率油层研究的现状。低电阻率油层主要分为内因、外因和复合成因3类,内因包括油层中含有高矿化度地层水、油层中含有较多的束缚水、粘土附加导电性、油层微孔隙发育、岩石骨架导电及岩石强亲水等;外因包含钻井液的侵入,油、水层对比条件发生变化,深侵入与测井探测范围有矛盾等;既有内因作用也有外因作用的则为复合成因。其评价和识别方法主要分为定性和定量2个方面。评价时应采取定性和定量方法相结合,并且与成因机制相匹配,由浅入深、从简单到复杂,逐步识别低电阻率油层。