CAJ | 학술논문

盆地火山岩及其储层的地震解释需要量化的岩相模型提供地质约束.三维揭露的盆缘剖面是实现岩相量化表征的最佳区.在松辽盆地东南隆起营城组建组剖面区开展了爆发相、喷溢相和侵出相的三维量化研究.爆发相出现在火山旋回早期,延伸千米量级、厚度百米量级,外形呈楔形尖灭状,坡度上陡下缓、呈平均15°左右的上凹形轮廓;始于热基浪亚相、向上为热基浪与空落亚相互层,终于热碎屑流亚相.喷溢相多出现在火山旋回中后期,覆于爆发相之上,延伸千米量级、厚度百米量级,外形呈凸透镜向外尖灭状,坡度上缓下陡、呈平均20°左右的上凸形轮廓;自下而上依次为下部、中部和上部亚相.侵出相出现在火山旋回后期,可见对其它相带呈切割一披覆关系的内、中、外三个亚相,侧向延伸和垂向厚度多为百米量级、通常最大不超过1km,呈顶缓缘陡的蘑菇状.用火山岩相模型约束井旁地震解释、建立岩相.地震相响应关系,可为无井区的火山岩地震识别提供模板.火山机构的后期改造只改变相序的完整性、不改变原始喷发相带间的相邻与相依性,不影响用岩相模式预测相变关系.非同源喷出物之间的叠置会干扰盆地火山岩相的解译,且使岩相模型的约束作用失效.
분지화산암급기저층적지진해석수요양화적암상모형제공지질약속.삼유게로적분연부면시실현암상양화표정적최가구.재송료분지동남륭기영성조건조부면구개전료폭발상、분일상화침출상적삼유양화연구.폭발상출현재화산선회조기,연신천미량급、후도백미량급,외형정설형첨멸상,파도상두하완、정평균15°좌우적상요형륜곽;시우열기랑아상、향상위열기랑여공락아상호층,종우열쇄설류아상.분일상다출현재화산선회중후기,복우폭발상지상,연신천미량급、후도백미량급,외형정철투경향외첨멸상,파도상완하두、정평균20°좌우적상철형륜곽;자하이상의차위하부、중부화상부아상.침출상출현재화산선회후기,가견대기타상대정절할일피복관계적내、중、외삼개아상,측향연신화수향후도다위백미량급、통상최대불초과1km,정정완연두적마고상.용화산암상모형약속정방지진해석、건립암상.지진상향응관계,가위무정구적화산암지진식별제공모판.화산궤구적후기개조지개변상서적완정성、불개변원시분발상대간적상린여상의성,불영향용암상모식예측상변관계.비동원분출물지간적첩치회간우분지화산암상적해역,차사암상모형적약속작용실효.
Seismic interpretation of volcanic rocks and corresponding reservoirs in petroliferous basins need to be disciplined by quantitative geological models. Three-dimensional sections outcroped on basin margin provide us with the best natural lab for us to construct quantitative models of volcanic facies. 3-D quantitative modelling of the major volcanic facies including explosive, effusive and extrusive has been carried out in the stratotype succession of Yingcheng Formation (K_1y) of southeast uplift of the Sengliao Basin. Explosive facies were developed in the early volcanic eruption cycles. Lateral-extension and vertical-thickness of the explosive facies is some thousand and several hundred meters respectively. They are wedge-shaped with a steeper upper slope and gentler lower slope showing an average slope angle of 15°. Successions of the explosive subfacies, from bottom to top, include base surge deposits, interbedding base surge and air-fall, and pyroclastic flow deposits. Effusive facies generally occured in the middle of an eruption cycle and covered on top of the explosive facies. They can extend up to some thousand meters and get a thickness up to several hundred meters. They are lenticular-shaped and pinch out laterally, with a gentler upper slope and steeper lower slope showing an average slope angle of 20°. Successions of the effusive subfacies from bottom to top include lower, middle and upper units. Extrusive facies generally occured at the end of an eruption cycle and are composed of inner, middle and outer units. They often cut through and cover other iithofacies. Their stretches and thickness are usually no more than 1 km. They are mushroom-shaped with a large flat roof and sharp border. Applying the above volcanic facies models to borehole-pass-by seismic interpretation, we established the respondence between volcanic facies and seismic information, with the help of which we may understand the meanings of seismic profiles of non-well areas. Erosion of a volcanic edifice will destroy parts of its facies but can not change the facies sequence, so that, it will not disturb the application of the facies models mentioned. On the other hand, if a volcanic body is composed of materials derived from different sources, called superimposed volcanic ediffice, application of these facies models may become problematic.