【作者】 季丽丹；

【导师】 杨兴科；

【作者基本信息】 长安大学 ， 构造地质学， 2007， 硕士

【摘要】 2003年乌参1井获得高产工业油气流,最近,神木1井白垩系又获重要发现,揭开了勘探开发乌什凹陷热潮的序幕。研究区资料控制十分有限,研究程度尚低,主要靠二维地震资料结合5口井的控制进行研究。对乌什凹陷来说,要尽快掌握储层分布范围及储层发育特征,尽快落实构造圈闭及其构造特征,同时提出下一步钻井优选目标,尽快展开对乌什凹陷的全区勘探开发。通过钻井的vsp标定,从过井剖面出发,协助搭起该区地震解释剖面框架,对工区地震剖面资料进行构造解释;完成中新生界地层分布图、构造纲要图、重点圈闭局部等时图;确定乌什凹陷中生界构造特征。通过完成四口井的岩芯观察和描述,做出单井沉积相分析;做储层评价。继而进行平面沉积相分析及储层预测,结合构造圈闭探讨该区的油气前景。在landmark工作站上进行三维、部分二维地震资料的解释,应用高分辨率地震资料,对该区构造、层序演化有个新的认识,指导沉积相展布研究。乌什凹陷是南天山与塔里木盆地北缘之间的中新生界前陆盆地。中生界主要分布在凹陷中东部,由南部边界古木别孜断裂系统控制中生界沉积,是一套砂岩、砾岩、泥岩及其过渡类型组成的陆相碎屑沉积,主要是扇三角洲-湖泊体系的沉积。在三叠、侏罗、白垩纪有湖盆扩张缩小和冲积扇、河流等沉积体的迁移及叠覆,亦有多次构造运动造成的削蚀。该区储层主要白垩系舒善河组,主要为砂砾岩的粗碎屑岩沉积,磨圆次棱一次圆,分选中等一好,成分成熟度南北变化较大,结构成熟度总体中等。砂岩半—固结,主要是次生溶蚀孔,成岩阶段划分为早成岩B阶段。储层段总体上属于低孔低渗和特低孔特低渗储层,且非均质性强。为超深层油藏,储盖配置优良,物性较差,横向分布较稳定。已有油气显示,综合评价为中等储集层。有利区域为凹陷东北部中生界构造岩性圈闭发育区、南天山山前背斜构造带、西瓜地层圈闭和C₂-P₁礁灰岩。更多还原

【Abstract】 Well Wucan 1 attained high yield flow of hot gas in 2003, and recently Well Shenmu 1 gains big indicating, which reveals the prelude of exploration and developing upsurge in Wushi Sag. Materials are really limited in research region, and research degree is still low, so we do studies generally basing on two dimensional seism data, as well as 5 wells. To Wushi Sag, it’s important to master the distributing bounds of the strata and reservoir features, and to carry out the traps and their structural features, and to submit next optimized target, which help to comprehensively explore and develop Wushi Sag.Through the VSP mark of the wells, and from the profiles through by the wells, we form the framework of seismic explaining profile in this area, and explain structural profiles of seismic profiles here. We finish strata distributing map of Mesozoic and Cenozoic Erathem, structure compendium map and isochronographs of major traps, and definite the structural features of Mesozoic Erathem in Wushi Sag. After observe and describe the cores of 4 wells, we analyze sedimentary facies of single wells and estimate the reservoir, and then complete the sedimentary facies plan and reservoir forecast, as well as discuss petroleum prospect in this region, combined to structural traps. Based on the explanation of three and two dimensional seism data on Landmark workstation, we got new realization on structure and sequence evolution, which direct the study of sedimentary facies distributing.Wushi Sag is Mesozoic and Cenozoic Erathem foreland between South Tianshan and the northern Tarim Basin. Mesozoic Erathem presents mainly in the mid and east of Wushi Sag, whose sediments are controlled by Gumubiezi Fault, the south bound, and is series of sand, conglomerate, mudstone and their transitional rock types. It’s continental debris sediments, generally fan delta-lake system. In Triassic, Jurassic, and Cretaceous period, the lake basin expanded and shrank, and the fan and the river moved and mantled, and also there were several structural erosions.Shushanhe formation Cretaceous system is the main reservoir here, is generally thick sediments of sand- conglomerate degree, whose psephicity varies from subround to subangular, and mid-well sorted, and composition maturity differs quite greatly between north and south, and structure maturity is mid degree generally. The sandstone is solidified-subsolidified, and their voids are mainly secondary voids, and the diagenetic stage is Early B. The reservoir is mainly low void- low permeability and very low void- very low permeability types, and meanwhile with great anisotropism. Oil deposits here are extra-deep, with good reservoir-capping equipment, quite poor physical property, and quite stable extent. It has got oil indicatings, is comprehensively estimated as mid reservoir. The optimized areas are structure- lithologic traps of Mesozoic Erathem in the northeast of the sag, anticline belt in the front of South Tianshan, Xigua lithologic trap, and reef limestone of C₂-P₁.更多还原