摘要
补偿中子测井通过测量含氢指数来表征地层孔隙度,由于岩石含氢量不完全分布于孔隙流体中且流体类型多样,在一定程度上限制了其反映地层孔隙度的准确性。为了明确含氢指数测量结果与地层孔隙度间存在差异的主要原因、深化地层认识,本文通过蒙特卡罗数值模拟,针对含氢指数测量涉及的多重因素开展分析工作。首先根据补偿中子测井仪含水灰岩的刻度响应,获取含氢指数与近远热中子计数比间的关系,然后开展分析工作并得到造成含氢指数与地层孔隙度存在差别的多种因素。研究结果表明:岩性、矿物组成、黏土、流体相态、地层水矿化度等因素均会对含氢指数测量产生影响,使其不同程度偏离地层孔隙度,尤其高密度、重泥质、含气量及高矿化度是影响含氢指数测量的主要因素。本研究为今后利用中子数据确定地层孔隙度及识别油气提供了一定参考。
The compensated neutron log(CNL)characterizes porosity by measuring hydrogen index(HI).However,its accuracy is not high due to the rock hydrogen content is not completely distributed in the pore fluid and fluid's types are complex.This study aims to determine the main reason for the difference between the measured HI and the formation porosity,thereby deepening the understanding of formation.Using Monte Carlo numerical simulation,multiple factors involved in the HI measurement are analyzed.First,the relationship between the HI and the near-to-far ratio of thermal neutron counting is obtained according to the calibration response of the compensated neutron tool in water-bearing limestone.Second,various factors that cause the difference between HI and formation porosity are obtained on the basis of a comprehensive analysis.The results show that lithology,mineral composition,clay,fluid state,formation water salinity will affect the measurement of HI and make it different from formation porosity.Particularly,high density,high shale content,gas content,and high salinity are the main factors affecting the HI measurement.Overall,this study provides a reference for determining formation porosity and identifying oil and gas through neutron data in the future.
作者
周悦
王猛
刘海波
吴晓龙
张传举
ZHOU Yue;WANG Meng;LIU Hai-Bo;WU Xiao-Long;ZHANG Chuan-Ju(Well-Tech Department,China Oilfield Services Limited,Langfang 065201,China)
出处
《物探与化探》
2026年第1期99-104,共6页
Geophysical and Geochemical Exploration
基金
中国海洋石油集团科技项目(CNOOC-KJ GJHXJSGGYF 2022-01)。
关键词
补偿中子测井
热中子减速
含氢指数
地层孔隙度
compensated neutron log(CNL)
thermal neutrondeceleration
hydrogen index(HI)
formation porosity
