松辽盆地北部古中央隆起带基底岩石弹性参数测试及特征分析  

Testing and characteristic analysis of elastic parameters of basement rock in the paleo-central uplift belt in the northern Songliao Basin

作　　者：戴世立[1] 王力娟 辛朝坤 DAI Shili;WANG Lijuan;XIN Zhaokun(Research Institute of Exploration and Development,Daqing Oilfield Company,PetroChina,Daqing,Heilongjiang 163712,China;PetroChina Daqing Geophysical Research Institute of GRI,BGP,Daqing,Heilongjiang 163453,China)

机构地区：[1]中国石油大庆油田有限责任公司勘探开发研究院,黑龙江大庆163712 [2]东方地球物理公司研究院大庆物探研究院,黑龙江大庆163453

出　　处：《石油地球物理勘探》2023年第2期443-453,共11页Oil Geophysical Prospecting

摘　　要：古中央隆起带基底上覆地层缺失断陷期沉积地层,基岩暴露地表时间长,风化壳普遍发育。基底岩性复杂,主要发育花岗岩、浅变质沉积岩及浅变质火山岩3大类岩石;基底主要发育花岗岩、变质岩储层,不同类型储层的裂缝发育程度不同。钻井揭示:花岗岩的脆性大,易形成裂缝,花岗岩储层物性最好,属于孔隙—裂缝型储层;基底花岗岩风化壳储层非均质性强,储层物性较差,以裂缝为主。目前有关基底花岗岩和变质岩的岩石物理弹性参数特征的实验室研究较少。为此,采用超声频段和地震频段弹性参数测试方法,系统分析了围压及孔隙压力对岩石纵、横波速度的影响,研究了不同孔隙度和饱和状态下岩石弹性参数与微裂缝密度及孔隙纵横比的关系;应用弹性参数交会分析,明确了基底风化壳储层及裂缝敏感参数,建立了符合基底孔隙—裂缝型储层特征的岩石物理模型,获得以下成果和认识:(1)对松辽盆地北部古中央隆起带基底33块岩性样品,采用超声频段和地震频段实验测试,测得的标准铝块的超声频段纵波速度(6430 m/s)与参考值(6400 m/s)基本相同,相对误差为0.5%,精度较高。(2)随着围压增加,在水饱和和气饱和状态下纵、横波速度均增大,且横波速度变化不大。随着孔压增加,在水饱和和气饱和状态下纵、横波速度均呈降低趋势,且在气饱和状态下纵波速度的变化量大于水饱和状态,在水饱和和气饱和状态下横波速度的下降趋势相似。(3)不同压力的超声频段和地震频段速度差异表明微裂隙是影响频散绝对变化量的主要因素,随着压力增加,微裂隙逐渐闭合,孔隙间的流体流动效应减弱,喷射效应降低。(4)地震频段和超声频段储层敏感参数优选结果相同,即v_(P)/v_(S)(纵横波速度比)、ν(泊松比)、λ(拉梅系数)、λ/μ(拉梅系数/剪切模量)、λ_(ρ)(拉梅系数×密度)等参数对流体最The overlying strata of the basement in the paleo-central uplift belt lack sedimentary strata in the fault depression period,and the bedrock has been exposed to the surface for a long time,with the crust of weathering developing widespread.The basement lithology is complex,and three major types of rocks,namely,granites,shallow metamorphic sedimentary rocks,and shallow metamorphic volcanic rocks,are developed.The basement mainly develops granite and metamorphic rock reservoirs,and the fracture development degree of different reservoirs varies.Well drilling reveals that granite is brittle and easy to form fractures.The Granite reservoir has the best physical property and belongs to the pore-fracture reservoir.The reservoir of the crust of weathering of granites in the basement has strong heterogeneity and poor physical property and is dominated by fractures.At present,there are few laboratory studies on the characteristics of petrophysical elastic parameters of granites in the basement and metamorphic rocks.Therefore,the elastic parameter testing methods of ultrasonic and seismic frequency bands are used to systematically analyze the effects of confining pressure and pore pressure on rock's P-wave and S-wave velocities and study the relationship between elastic parameters of the rock and micro-fracture density,as well as pore's aspect ratio under different porosity and saturation conditions.According to the cross-analysis of elastic parameters,the sensitive parameters of the reservoir and fractures of the crust of weathering in the basement are defined,and a petrophysical model conforming to the characteristics of the pore-fracture reservoir in the basement is established.The following understandings are obtained:①The ultrasonic and seismic frequency bands are used to test the 33 lithologic samples from the basement in the paleo-centric uplift belt in the northern Songliao Basin.The measured P-wave velocity(6430 m/s)of the standard aluminum block by ultraso-nic frequency band is basically the same as the referenc

关 键 词：古中央隆起带 基底 超声频段 地震频段 岩石物理测试 物性参数 弹性参数 

分 类 号：P631[天文地球—地质矿产勘探]