志丹油田洛河区块长6^1低阻油层测井识别方法研究

Study on Logging Identification Method of Chang 6^1 Low Resistivity Reservoir in Luohe Block,Zhidan Oilfield

陕北志丹油田洛河区块长6^1油层作为该区块的主力油层,区域内低阻油藏较为发育,但由于低阻成因机理较为复杂、表现形式多样,常规识别方法符合率较低。通过对岩心化验分析资料及测井资料的对比分析,认为束缚水饱和度高、地层水矿化度高是形成低电阻率油层的主要油藏背景条件。根据淡水钻井液侵入对油层、水层深浅电阻率影响的差异,运用侵入因子识别法和横向对比识别法可有效提高对低阻油藏的识别符合率。

Chang 6^1 reservoir in Luohe block of Zhidan oilfield in northern Shaanxi is the main reservoir in this block,and the low resistivity reservoir is well developed in the area,but because of the complex genetic mechanism and various forms of low resistivity,the coincidence rate of conventional identification methods is low.Through the comparative analysis of core laboratory analysis data and logging data,it is considered that high irreducible water saturation and high salinity of formation water are the main reservoir background conditions for the formation of low resistivity reservoirs.According to the difference of the influence of fresh water drilling fluid invasion on the deep and shallow resistivity of oil layer and water layer,the identification coincidence rate of low resistivity reservoir can be effectively improved by using invasion factor identification method and lateral contrast identification method.