【作者】 敖丽英；

【导师】 徐国强；

【作者基本信息】 成都理工大学 ， 矿产普查与勘探， 2011， 硕士

【摘要】 准噶尔盆地是我国第二大盆地,油气资源丰富,车排子地区位于准噶尔盆地西北缘。目前该地区已进入高成熟勘探阶段,由于研究区处于一宽缓的鼻隆构造带,呈单斜构造,构造圈闭不发育,因此,以寻找岩性圈闭为主。近年来车排子地区浅层新近系沙湾组发现了数量可观的工业油气流,推测尚有很大的潜力,然而,该地区浅层一直以来缺乏系统的层序地层和沉积体系研究,阻碍了岩性圈闭寻找。针对上述问题,论文以地震地层学、层序地层学及沉积学理论为指导,综合运用钻井、测井、地震等资料,结合区域地质背景,对车排子地区春光区块沙湾组地层进行了层序地层划分与对比,建立了沙湾组的层序地层格架,在层序地层格架内对沉积体系进行了系统的研究,主要取得了一下几点认识:1)以O. Catuneanu（2009）等教授提出的层序地层标准化理论为指导,综合运用钻井、测井、地震等资料,将沙湾组划分为3个三级层序,即SQ1、SQ2、SQ3,大致对应于沙湾组的N₁s¹、N₁s²、N₁s³段,并且每个三级层序都分为4个体系域,分别是低位体系域、湖侵体系域、高位体系域及强制湖退体系域。2)选取了一条贯穿全区、大致沿物源方向的典型剖面,对其线描,进行沉积盆地原形恢复,建立了SQ2层序（沙二段）的层序地层格架模式,明确了地层内部结构、沉积趋势、堆砌方式、接触关系、研究砂层组沿物源方向的展布及发育的沉积相类型。3)大量的纯砂泥岩速度提取与分析表明:研究区发育三种类型的砂岩:Ⅰ型砂:砂岩速度小于泥岩速度的砂岩;Ⅱ型砂:砂岩速度与泥岩速度相当的砂岩;Ⅲ型砂:砂岩速度大于泥岩速度的砂岩,沙二段以Ⅰ型砂为主。井-震对比分析表明地震波谷为砂层顶面地震响应。4)在上述分析研究基础之上,应用砂体地震扫描解释方法对砂层组进行扫描解释,得到了骨架砂体的平面展布,通过单井相、地震相分析,认为研究区发育浅水辫状河三角洲平原、浅水辫状河三角洲前缘、斜坡扇及湖底扇,其中三角洲平原主要发育分流河道及河道间湾微相;三角洲前缘主要沉积分流河道砂体和滩坝砂体;斜坡扇发育大量连片的斜坡扇砂体;湖底扇主要发育叠覆扇砂体,此外,斜坡扇和湖底扇均发育有少量的水下分流河道砂体。5)在沉积相研究基础之上,综合物源分析、沉积构造背景等资料,沙二段第三砂层组沉积体系发育情况如下:研究区西部和中部发育浅水辫状河三角洲平原—浅水辫状河三角洲前缘—斜坡扇—湖底扇沉积体系,东部仅发育浅水辫状河三角洲平原沉积体系6)综上,建立了沙二段第三砂层组的沉积相模式,指出了岩性圈闭发育的有利相带。更多还原

【Abstract】 Junggar Basin is the second largest basin in China, which is rich in oil or gas. And the Chepaizi area is located at the northwest margin of the Junggar Basin. At present, the oil or gas exploration of this area has stepped into a deep study phase. Because the study area belongs to a nose structure belt, it is lack in structural trap and the lithologic trap is the main goal. The considerable industry oil production has been found in the low level Shawan formation whose age is neogene. So we suppose that this area has oil exploration potential. And it has not carried out the sequence stratigraphy and sedimentary system research which is assisted to find the lithologic trap.For solving the problem above, we take advantage of the seismic, log and drilling data integrated the geologic background as well as instructed by seismic stratigraphy, sequence stratigraphy and sedimentology theory to divide the sequence stratigraphy and compare them. And then we build the sequence stratigraphy framework of the Shawan formation. At last, we study the sedimentary system systematically and have some new knowledge as followed:1)Instructed by the sequence stratigraphy calibrating theory raised by O. Catuneanu（2009）, we divide the Shawan formation into three Third-order sequences: SQ1,SQ2,SQ3, which correspond the three sections of the Shawan formation: N₁s¹、N₁s²、N₁s³ approximately. And each section can be subdivided into four tracts including: Lowstand System Tract （LST）, Trangressive System Tract （TST）, High System Tract （HST） and Force Regressive System Tract （FRST）.2)We select one typical profile which goes through the whole study area and is Source Direction strike. And then we carry on curve tracing with it as well as original basins restored. At the same time, we determine internal structure, deposition trend, accumulation mode, contacting relationship and the distribution of the source direction of the SQ2.3)By extracting the values of the velocity from large number of sandy mudstone sections and interpreting them, we find three types of sand in our study area, which include:Ⅰtype, the velocity of sand is slower than the mud stone;Ⅱtype, the velocity of sand is about the same as mud stone;Ⅲtype, the velocity of sand is faster than the mud stone. And the second section of the Shawan formation has theⅠtype sand. By comparison and analysis of the well and seismic profile, the trough indicates the top of the sand.4) Based on the study above, we scan the sand body by application of the seismic scanning and interpreting method and get the distribution of the sand framework in the plane. Using the individual well and seismic face analysis, we think it develops shallow water braided river delta plain, delta front, slop and floor fan facies. Besides, the plain includes distributary channel and interdistributary estuary sand mainly; the delta front develops subaqueous distributary channel and mouth bar sand; the slop and floor fans develop a few of subaqueous distributary channel sand and the latter has much of sand body overlaying.5) Integrated the source direction and tectonic background, we think that the third sand bed in the second section of the Shawan formation develops shallow water braided river delta plain- shallow water braided river delta front-slop fan-floor fan in the west and central part of the study area, in the east area there is only shallow water braided river delta plain.6) Overall, we build the sedimentary facies model of the third sand set in the second section of the Shawan formation, point out the location where the lithologic traps develop.更多还原