摘要
致密砂岩电阻率与孔隙度关系存在"非阿尔奇"特征.为明确致密砂岩电阻率与孔隙度的关系及规律,并建立适用于致密砂岩的地层因素计算方法,基于多个致密砂岩油气区实验数据对电阻率随孔隙度变化的规律及地层因素计算方法进行了研究.通过对来自3个盆地8个油气田的岩石物理实验数据分析,证实了致密砂岩地层因素与孔隙度在双对数坐标下呈现分段线性关系,孔隙度约等于10%处出现明显拐点;拟合了孔隙度小于10%时具有通用性的阿尔奇公式参数.红河油田致密砂岩压汞实验数据表明,孔隙度小于10%的岩样与孔隙度大于10%的岩样孔喉半径分布有显著差异,由此将孔隙分为大孔径孔隙和小孔径孔隙,假设其分别具有不同比例的"宏导电孔隙",并定义了"伪宏导电孔隙度"变量,岩电-压汞联测实验数据表明,伪宏导电孔隙度与地层因素在双对数坐标下表现为良好的单一线性关系,由此建立了阿尔奇公式改进式,改进式在不同孔隙度条件下形式和参数均保持统一,计算地层因素效果更好.利用红河油田及塔里木盆地志留系致密砂岩岩样岩电实验数据检验改进式计算效果,证实了改进式的可靠性.
There is a ＂non-Archie ＂ phenomenon present in the relationship between porosity and resistivity in tight sandstone,which leads to the water saturation of tight sandstone reservoir calculated by traditional Archie formula in low value. To establish water saturation evaluation method suitable for tight sands, the primary task is to determine the relationship between resistivity and porosity of the tight sandstone,then to establish a reliable formation factor calculation method. All these researches in this paper are based on the core experimental data of tight sands in multiple oilfields.Through petrophysical experiments analysis of core rock data from eight oilfields of three basin, it has been confirmed that formation factor and porosity of tight sandstone show a piecewise linear relationship in double logarithmic coordinates. The significant inflection point appears when porosity is approximately equal to10%, according to that, the Archie parameters with versatility could be fitted when porosity is less than 10%. Mercury injection experimental data in Honghe oilfield shows that core pore throat distributions present significant differences when the core porosity is less than 10% and when it is more than 10%. Therefore,the pore is divided into large-diameter pore part and small-diameter pore part,each part of which is supposed to have a different proportion of＂macro conductive pore ＂ and is defined as ＂pseudo macro conductive porosity＂variables. The combined measurements data of core electricity and mercury injection experiments indicate that the pseudo macro conductive porosity and formation factor display a good single linear relationship in double logarithmic coordinates.Thus we establish the improved Archie formula,the expression and parameters of which keep unified under different porosity conditions.This formula behaves better application effect in formation factor calculation.The calculation effect is examined and improved by core electricity experiments data of tight sandstone samples in the
出处
《地球物理学进展》
CSCD
北大核心
2016年第2期695-700,共6页
Progress in Geophysics
基金
中国石化科技攻关项目(P13111)
中国石化青年科技创新基金(P14136)联合资助
关键词
致密砂岩
孔电关系
地层因素
宏导电孔隙
阿尔奇公式
tight sandstone
pore-electricity relationship
formation factor
macro conductive pore
Archie formula
