河套盆地临河坳陷临河组岩性、岩相及生储盖特征
发布时间：2018-12-11 20:57
【摘要】：河套盆地临河坳陷是油气勘探的重要地区,一直以来备受人们的关注。该区共钻井11 口,有6 口井见油显示,但未获得工业油流。由于前期钻井主要集中在临河坳陷的东南部,对该区目的层岩性、沉积相、烃源岩以及储盖特征的研究主要基于这些资料,精度和准确度受到一定限制。本文以2014年所钻位于研究区中部的探井L1井为重点研究对象,结合其它井资料和地震资料,采用岩心观察、分析测试、ECS资料岩性识别、古构造恢复、综合研究等方法对临河坳陷临河组的岩性、岩相及生储盖特征开展了进一步研究。取得的主要认识如下:1、本文采用两种岩性划分方法来研究L1井临河组的岩性特征。其一,采用ECS资料和新的岩性解释方法(该方法可以有效地识别出碳酸盐岩),依据矿物成分含量进行岩性划分,结果表明:L1井临河组岩性主要有石英碎屑岩和杂岩,另发育长石碎屑岩、碳酸盐岩、含膏沉积岩;其二,按传统岩性划分(依据粒度对碎屑岩岩性进行划分,依据矿物成分含量对碳酸盐岩进行划分),结果表明:L1井临河组岩性有泥岩、粉砂质泥岩、白云质泥岩、含膏质泥岩、粉砂岩、细砂岩、中粗砂岩和含细砾粗砂岩。2、依据孢粉、微量元素及岩性特征提出,L1井临河组为干旱半咸水-咸水的沉积环境,还原性较强。临河坳陷临河组沉积亚相类型主要有半深湖、浅湖、滨浅湖-三角洲平原亚相。其中,深灰色细粒碳酸盐岩的存在表明半深湖亚相在平面上具有较大的分布范围。在区域上由L1井往西北方向泥岩变厚,地震反射层连续性变好,反映出由L1井往西北方向沉积相带(水体)变深。3、L1井临河组烃源岩岩性主要为深灰色、灰色泥岩,按矿物成分分类,岩性主要为杂岩、粘土岩、碳酸盐岩与细粒石英碎屑岩。临河组烃源岩累计厚度235m,占地层厚度的25.74%,单层厚度平均2.43m,最大12m。依据L1井56个样品地球化学分析资料,临河组烃源岩类型以Ⅰ型和Ⅱ型为主,有机质丰度大(有机碳含量达4.09%),R0在0.76%-1.06%之间。依据烃源岩的区域沉积相及埋藏幅度特征,L1井西北部烃源岩有机质丰度会更大、类型更好、成熟度更高,生油岩累积厚度更厚。4、根据岩石力学性质将临河坳陷新生界沉积岩沉积后变化分为三个阶段即塑性压实段、弹塑性压缩段和破裂段。目前,渐新统临河组沉积岩主体处于破裂段,发育中-高渗孔隙性砂岩类、裂缝性泥质岩类的储集层以及泥质岩类缝改盖层;中新统沉积岩主体处于弹塑性压缩段,发育孔隙性泥岩盖层和孔隙性砂岩储层,泥质岩盖层厚度和分布范围较大;上新统沉积岩主体处于塑性压实段,发育孔隙性砂岩类储层及少量的泥质岩类盖层。5、综合临河坳陷生储盖及构造、埋藏的特点,建议临河坳陷下一步的油气勘探围绕L1井西北部杭后断裂开展,该区更接近有利生油区,可发育下生上储式(临河组生,中、上新统储)和自生自储式(临河组生,临河组储)的生储盖组合。
[Abstract]:Linhe depression in Hetao Basin is an important area for oil and gas exploration. There are 11 drilling wells in this area, 6 wells show oil, but no industrial oil flow. Because the early drilling is mainly concentrated in the southeast of Linhe depression, the study of lithology, sedimentary facies, source rock and reservoir cap characteristics of the target layer in this area is mainly based on these data, and the accuracy and accuracy are limited to a certain extent. This paper takes L1 well drilling in the middle of the research area in 2014 as the research object, combining with other well data and seismic data, using core observation, analysis and test, lithology identification of ECS data, paleotectonic recovery. The lithology, lithofacies and reservoir-caprock characteristics of Linhe formation in Linhe depression were further studied by means of comprehensive study. The main results are as follows: 1. Two lithologic classification methods are used to study the lithologic characteristics of Linhe formation in well L1. First, ECS data and a new lithologic interpretation method (which can effectively identify carbonate rocks) are used to divide lithology according to mineral composition content. The results show that the lithology of Linhe formation in well L1 mainly consists of quartz clastic rocks and complex rocks. In addition, feldspar clastic rocks, carbonate rocks and gypsum sedimentary rocks are developed. Secondly, according to the traditional lithology (the clastic lithology is divided according to the granularity, the carbonate rock is divided according to the mineral composition content), the result shows that the lithology of Linhe formation of well L1 has mudstone, silty mudstone, dolomite mudstone, 2. According to the characteristics of sporopollen, trace elements and lithology, Linhe formation of well L1 is a depositional environment of arid brackish water and brackish water. The sedimentary subfacies of Linhe formation in Linhe depression are mainly semi-deep lake, shallow lake, littoral shallow lacustrine delta plain subfacies. The existence of dark gray fine-grained carbonate rocks indicates that the semi-deep lacustrine subfacies have a large distribution range on the plane. In the region, mudstone is thickened from well L1 to northwest and the continuity of seismic reflection layer is improved, which reflects that the sedimentary facies zone (water body) from well L1 to northwest becomes deeper. The source rocks of Linhe formation in well 3Gui L1 are mainly dark gray and grey mudstone. According to the mineral composition, the lithology is mainly composed of complex rock, clay rock, carbonate rock and fine quartz clastic rock. The accumulative thickness of source rock in Linhe formation is 235 m, the thickness of the cover layer is 25.74%, the average thickness of single layer is 2.43 m, and the maximum is 12 m. According to the geochemical analysis data of 56 samples from well L1, the source rocks of Linhe formation are mainly of type 鈪，
本文编号：2373210
[Abstract]:Linhe depression in Hetao Basin is an important area for oil and gas exploration. There are 11 drilling wells in this area, 6 wells show oil, but no industrial oil flow. Because the early drilling is mainly concentrated in the southeast of Linhe depression, the study of lithology, sedimentary facies, source rock and reservoir cap characteristics of the target layer in this area is mainly based on these data, and the accuracy and accuracy are limited to a certain extent. This paper takes L1 well drilling in the middle of the research area in 2014 as the research object, combining with other well data and seismic data, using core observation, analysis and test, lithology identification of ECS data, paleotectonic recovery. The lithology, lithofacies and reservoir-caprock characteristics of Linhe formation in Linhe depression were further studied by means of comprehensive study. The main results are as follows: 1. Two lithologic classification methods are used to study the lithologic characteristics of Linhe formation in well L1. First, ECS data and a new lithologic interpretation method (which can effectively identify carbonate rocks) are used to divide lithology according to mineral composition content. The results show that the lithology of Linhe formation in well L1 mainly consists of quartz clastic rocks and complex rocks. In addition, feldspar clastic rocks, carbonate rocks and gypsum sedimentary rocks are developed. Secondly, according to the traditional lithology (the clastic lithology is divided according to the granularity, the carbonate rock is divided according to the mineral composition content), the result shows that the lithology of Linhe formation of well L1 has mudstone, silty mudstone, dolomite mudstone, 2. According to the characteristics of sporopollen, trace elements and lithology, Linhe formation of well L1 is a depositional environment of arid brackish water and brackish water. The sedimentary subfacies of Linhe formation in Linhe depression are mainly semi-deep lake, shallow lake, littoral shallow lacustrine delta plain subfacies. The existence of dark gray fine-grained carbonate rocks indicates that the semi-deep lacustrine subfacies have a large distribution range on the plane. In the region, mudstone is thickened from well L1 to northwest and the continuity of seismic reflection layer is improved, which reflects that the sedimentary facies zone (water body) from well L1 to northwest becomes deeper. The source rocks of Linhe formation in well 3Gui L1 are mainly dark gray and grey mudstone. According to the mineral composition, the lithology is mainly composed of complex rock, clay rock, carbonate rock and fine quartz clastic rock. The accumulative thickness of source rock in Linhe formation is 235 m, the thickness of the cover layer is 25.74%, the average thickness of single layer is 2.43 m, and the maximum is 12 m. According to the geochemical analysis data of 56 samples from well L1, the source rocks of Linhe formation are mainly of type 鈪，
本文编号：2373210
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