泥岩压实研究中有机质导致声波时差异常的定量校正方法

发布时间：2018-03-26 22:01

本文选题：声波时差　切入点：压实曲线　出处：《中国石油大学学报(自然科学版)》2016年03期

【摘要】：高丰度有机质导致的声波时差异常高值不能客观反映地层孔隙度的变化,定量研究有机质对压实曲线的影响才能减小压实研究结果的不确定性。从泥岩压实研究的原理出发,构建考虑干酪根的岩石等效体积模型,提出有机质引起声波时差增量的校正公式;以鄂尔多斯盆地南部镇泾地区为例,讨论压实曲线有机质校正方法的实用性及可靠性。结果表明:烃源岩层段高丰度有机质往往造成压实规律的较大误差,压实研究中应当消除有机质对声波时差的影响;镇泾地区泥岩压实曲线经过校正后,正常压实趋势线斜率减小约30%~55%;长7段底部页岩欠压实幅度显著降低,最大埋深时期的剩余压力约为3~5 MPa,相比于校正前降低5~8 MPa,反映出以往研究可能过高地估计了长7段古超压的幅度;利用校正后声波时差计算的泥岩孔隙度与实测孔隙度吻合性较好,且计算的流体压力与数值模拟结果一致,证实提出的定量校正方法能够有效地消除研究区有机质造成的声波时差异常,可作为鄂尔多斯盆地及其他地区压实研究的借鉴。
[Abstract]:The high value of sonic time difference caused by high abundance organic matter can not objectively reflect the change of formation porosity. Only by studying quantitatively the influence of organic matter on compaction curve can the uncertainty of compaction research result be reduced. Based on the principle of mudstone compaction study, The equivalent volume model of rock considering kerogen is constructed, and the correction formula of acoustic time difference increment caused by organic matter is put forward, taking Zhenjing area in the south of Ordos Basin as an example, The practicability and reliability of organic matter correction method for compaction curves are discussed. The results show that the high abundance organic matter in source rock formation often leads to large errors in compaction law and the influence of organic matter on acoustic moveout should be eliminated in compaction research. After correcting the compaction curve of mudstone in Zhenjing area, the slope of the normal compaction trend line decreases by about 300.55, and the undercompaction amplitude of shale at the bottom of Chang7 section decreases significantly. The residual pressure in the period of maximum buried depth is about 3 ~ 5 MPA, which is 5 ~ 8 MPA lower than that before correction, which indicates that the amplitude of paleo overpressure in Chang 7 segment may be overestimated by previous studies. The porosity of mudstone calculated by corrected acoustic moveout is in good agreement with the measured porosity, and the calculated fluid pressure is in agreement with the numerical simulation results. It is proved that the proposed quantitative correction method can effectively eliminate the sonic time difference anomaly caused by organic matter in the study area and can be used as a reference for the compaction study in Ordos Basin and other areas.
【作者单位】：中国科学院地质与地球物理研究所油气资源研究重点实验室;中国科学院大学;中国石油大学地球科学与技术学院;中国石化石油勘探开发研究院;
【基金】：国家自然科学基金项目(41372151) 国家科技重大专项(2011ZX05008-004) 中国博士后科学基金项目(2015M570148)
【分类号】：TE311

【相似文献】