局部地应力对地层速度及构造解释的影响  

Influence of local in-situ stress on interpretation of interval velocity and tectonic

作　　者：刘振 李黎 戴建文 沈水荣 LIU Zhen;LI Li;DAI Jianwen;SHEN Shuirong(Shenzhen Branch of China National Offshore Oil Corporation,Shenzhen,Guangdong 518041,China)

机构地区：[1]中海石油(中国)有限公司深圳分公司,广东深圳518041

出　　处：《石油地球物理勘探》2022年第5期1164-1173,1191,I0008,共12页Oil Geophysical Prospecting

摘　　要：地应力是地层压实作用的主控因素之一,应力变化必然引起压实作用的变化,进而影响地层速度及基于地震资料的构造解释。迄今未见地应力横向变化对地层速度及构造解释影响的定量分析文献。为此,基于测井数据,参考了土木工程、固体矿产、钻井工程等领域的研究成果,采用有限差分法模拟应力场,分析局部地应力对地层速度的影响机理。得到以下认识:(1)局部范围内的速度变化主要受局部应力场变化的影响,且对勘探初期的油气田储量评估影响较大;(2)披覆背斜构造高点至翼部垂向地应力减小,且埋深越大变化越快;(3)滚动背斜垂向地应力向断层方向增大,而且距断层越近、埋深越大变化越快;(4)在地应力影响下,上述两类构造高部位的层速度及平均速度较翼部高,且埋深越大变化越快。油田钻探实例证实了上述认识,可见,地应力场是地层速度变化的重要影响因素之一,在地震勘探中有必要予以关注。In-situ stress is one of the main controlling factors affecting formation compaction.Changes in this stress inevitably lead to changes in compaction,which further affect interval velocity and tectonic interpretation based on seismic data.However,no relevant literature has been found that quantitatively analyzes the influence of lateral changes in in-situ stress on interval velocity and tectonic interpretation.For this reason,drawing on logging data and research results in civil engineering,solid minerals,drilling engineering,and other fields,this study simulated the stress field by the finite difference method and analyzed the influence mechanism of local in-situ stress on interval velocity.The following understandings were gained from the analysis:(1)Velocity variation on a local scale is mainly affected by the variation of the local stress field,and it has a great influence on the reserve evaluation of oil and gas fields at the initial stage of exploration.(2)As for the drape anticline,the vertical in-situ stress decreases in the direction from the structural high to the wing,and the change quickens with the increase in burial depth.(3)Regarding the rollover anticline,the vertical insitu stress increases in the direction to the fault,and the change speeds up as the fault draws near and burial depth increases.(4)Under the influence of in-situ stress,interval velocity and average velocity at the structural high are higher than those at the wing in these two types of structures,and the changes quicken with the increase in burial depth.Examples of drilled oil fields confirmed the above understandings.Therefore,the insitu stress field is one of the important geological factors affecting the variation of interval velocity,and it should be taken into account in seismic exploration.

关 键 词：局部地应力 地应力模拟 披覆背斜 滚动背斜 层速度 平均速度 

分 类 号：P631[天文地球—地质矿产勘探]