白驹凹陷位于苏北盆地东台坳陷的东北部,可以划分为2段,自下而上分别为泰二段和泰一段,泰一段又分为泰一1小层、泰一2小层和泰一3小层。研究表明,在白驹凹陷泰一段时期,发育辫状河三角洲、曲流河三角洲、湖泊、共3种沉积相类型,其中以湖泊相、辫状河三角洲相、曲流河三角洲相为主。泰一段3小层主要发育辫状河三角洲、东南发育范围较小的滨浅湖相,泰一段2小层表现为西南西北方向为三角洲前缘相,整个东方向湖侵,发育湖相,泰一段1小层,湖退,发育曲流河三角洲前缘,西南发育的湖相。 Baiju sag is located in the northeast of Dongtai depression in Subei basin. It can be divided into two sections, the second and the first member of Tai from bottom to top, and the first member of Tai is further divided into small layer of tai-1, small layer of tai-2 and small layer of layer Tai-3. The study shows that during the first member of Tai formation in Baiju sag, braided river delta, meandering river delta and lake were developed, among which lacustrine facies, braided river delta facies and meandering river delta facies were the main sedimentary facies. Braided river delta and shore shallow lacustrine facies in the southeast are mainly developed in sublayer 3 of member 1 of Tai 1. The 2 small layers in the first section of Tai show the leading delta facies in the southwest and northwest direction, and lacustrine facies in the whole east direction, while the 1 small layer in the first section of Tai shows the lacustrine facies in the front of mean-river delta and in the southwest.
白驹凹陷位于苏北盆地东台坳陷的东北部,可以划分为2段,自下而上分别为泰二段和泰一段,泰一段又分为泰一1小层、泰一2小层和泰一3小层。研究表明,在白驹凹陷泰一段时期,发育辫状河三角洲、曲流河三角洲、湖泊、共3种沉积相类型,其中以湖泊相、辫状河三角洲相、曲流河三角洲相为主。泰一段3小层主要发育辫状河三角洲、东南发育范围较小的滨浅湖相,泰一段2小层表现为西南西北方向为三角洲前缘相,整个东方向湖侵,发育湖相,泰一段1小层,湖退,发育曲流河三角洲前缘,西南发育的湖相。
白驹凹陷,泰州组一段,沉积相
Yanqi Wu
School of Earth Sciences, Yangtze University, Wuhan Hubei
Received: Oct. 8th, 2020; accepted: Oct. 22nd, 2020; published: Oct. 29th, 2020
Baiju sag is located in the northeast of Dongtai depression in Subei basin. It can be divided into two sections, the second and the first member of Tai from bottom to top, and the first member of Tai is further divided into small layer of tai-1, small layer of tai-2 and small layer of layer Tai-3. The study shows that during the first member of Tai formation in Baiju sag, braided river delta, meandering river delta and lake were developed, among which lacustrine facies, braided river delta facies and meandering river delta facies were the main sedimentary facies. Braided river delta and shore shallow lacustrine facies in the southeast are mainly developed in sublayer 3 of member 1 of Tai 1. The 2 small layers in the first section of Tai show the leading delta facies in the southwest and northwest direction, and lacustrine facies in the whole east direction, while the 1 small layer in the first section of Tai shows the lacustrine facies in the front of mean-river delta and in the southwest.
Keywords:Baiju Sag, The First Member of Taizhou Formation, Sedimentary Facies
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随着我国国民经济快速发展,对天然气需求越来越大,并且存在夏季和冬季需求不平衡的矛盾,因此加大和加快储气库建设以解决冬季天然气调峰问题显得尤为重要。华东地区是我国经济发达地区,该区储气库建设相对滞后,加快该区储气库选址和建设尤为迫切。因此,急需将白驹构造纳入储气库之中,扩大建库面积。该项目对减缓华东地区冬季天然气调峰具备重要意义。所以作者在根据前人对相邻工区的研究经验上,应用沉积学和层序地层学的研究原理和方法,对泰一段的沉积相类型、沉积相平面展布进行研究,期望为预测有利砂体的平面分布的后续工作提供依据。
白驹凹陷位于苏北盆地东台坳陷的东北部,东临裕华、小海凸起,南接吴堡低凸起和梁垛低凸起相接,西靠柘垛低凸起,北依建湖隆起,面积约2180 km2 [
在地震方面,泰一段顶部低Gr,高阻,粉砂岩底部低Gr,高阻整体发育砂泥互层,整体为低Gr,高阻,为三角洲–湖相沉积(图1)。
通过对白驹凹陷11口井岩心观察描述及室内镜下鉴定、粒度分析和古生物分析等资料的研究,并依据测井、地震响应特征和沉积层序、砂体分布特征 [
图1. 研究区泰一段单井沉积相综合柱状图
沉积相 | 沉积亚相 | 沉积微相 | 岩性特征 | 发育层位 |
---|---|---|---|---|
辫状河三角洲 | 辫状河三角洲前缘 | 水下分流河道 | 细砾岩,细砂岩沉积为主,砾石混杂堆积,多为棱角状,砂质沉积增多,砂地比高,块状层理 | 泰一3小层 |
支流间湾 | 暗色泥岩沉积为主,夹薄层砂砾岩沉积 | |||
曲流河三角洲 | 曲流河三角洲前缘 | 水下分流河道 | 以含砾细砂岩或细砂岩沉积为主,砾石磨圆为次圆状圆,厚度规模相对较小,块状层理 | 泰一1小层 |
支流间湾 | 暗色泥岩沉积为主,夹少量粉细砂岩沉积 | |||
湖泊 | 滨浅湖 | 滨浅湖泥 | 泥岩沉积为主,煤层相对发育,常见炭化泥岩 | 泰一1小层、2小层、3小层 |
砂坝 | 以砂岩沉积为主,见反旋回沉积 | |||
半深湖 | 半深湖泥 | 暗色泥岩沉积为主 |
表1. 研究区沉积相类型及特征
由研究区的均方根属性图与砂地比图、砂岩厚度图对比可以发现均方根属性与砂体之间存在某种关系:厚砂体对应了高均方根振幅,且砂体展布形态和高均方根振幅的展布形态类似。通过上述分析发现均方根振幅属性和砂体展布这两者的相关性较好 [
由白驹地区泰一段3小层均方根振幅属性图可知:丰503井西北侧,丰探3井东北侧,丰探1井西南侧,丰探9井东南侧均为红蓝色分布区域,代表着曲流河三角洲的沉积体系的边界 [
图2. 泰一段3小层均方根振幅属性
图3. 泰一段3小层沉积相平面分布图
由白驹地区泰一段2小层均方根振幅属性图可知:在西南部以及西北部边缘位置出现中高值绿色,其他方向为蓝色的的低值中间夹杂一些中高值绿色。沉积相表现为西南西北方向为三角洲前缘相,整个东方向湖侵,发育湖相(图4、图5)。
图4. 泰一段2小层均方根振幅属性
图5. 泰一段2小层沉积相平面分布图
由白驹地区泰一段1小层均方根振幅属性图可知:在西侧和东北侧出现三个绿色和红黄色的区域,在西侧北侧中部和东南侧出现一些蓝色的的区域,代表着曲流河三角洲的沉积体系的边界。所以泰一段1小层,湖退,发育曲流河三角洲前缘,西南发育的湖相(图6、图7)。
图6. 泰一段1小层均方根振幅属性
图7. 泰一段1小层沉积相平面分布图
1) 确立了白驹含水层5种沉积微相类型,编制了白驹含水层沉积微相平面分布图,揭示了该区沉积微相演化特征,总体为湖侵–湖退–湖侵沉积过程。白驹凹线泰州组一段共发育3类沉积相,以湖泊相、辫状河三角洲相、曲流河三角洲相为主。进一步细分为4种沉积亚相和7种沉积微相。
2) 泰一段3小层主要发育辫状河三角洲、东南发育规模较小的滨浅湖相,泰一段2小层表现为西南西北方向为三角洲前缘相,东部发育湖相,泰一段1小层,发育曲流河三角洲前缘,西南发育湖相。
吴炎圻. 白驹凹陷泰州组一段沉积相展布特征Distribution Characteristics of Sedimentary Facies in the First Member of Taizhou Formation in Baiju Sag[J]. 地球科学前沿, 2020, 10(10): 992-998. https://doi.org/10.12677/AG.2020.1010098