通江铁厂河地区长兴组生物礁—滩组合发育与地裂运动的关系

发布时间：2019-06-07 18:48

【摘要】：四川盆地东北部广泛发育有上二叠统长兴组的生物礁滩组合相,而生物礁-滩组合相为重要的油气储集岩发育地区,故对该生物礁滩组合相带的分布及其发育特征的研究具有重要意义。众所周知,沉积相带的分布又受控于构造运动,因而通过对生物礁滩的发育分布与峨眉地裂运动的关系研究能更好的指导油气勘探。 通江铁厂河上二叠统长兴组生物礁是川东北地区地表发现的生物礁的又一代表,通过野外4条剖面的测制及详细的室内研究,认为该区长兴组发育有生物礁及生物碎屑浅滩组合相,圆丘状点礁与浅滩叠置构成纵向上三个旋回的礁、滩复合体。生物礁的造礁生物主要为海绵,含量20%～50%,附礁生物主要有藻类、有孔虫、蜓类等,主要造礁方式为障积作用。单个礁体的发育规模虽然较小,但其组合相带特征明显,下部礁基为灰色中-厚层生物屑泥粒岩,含生物碎屑较多;礁核部发育有形态完整的串管海绵,长5～8cm,宽约3～6cm,海绵直立生长,也有横卧生长;礁盖及礁顶发育薄-中层生物屑泥粒岩及细晶白云岩;礁翼见有燧石结核;礁间为厚度较大的生物碎屑浅滩沉积。 储层岩性主要以礁灰岩及生物屑亮晶灰岩为主,岩石白云化程度较低。孔洞较丰富,但多被方解石晶体充填。储层经过多种成岩作用的改造,主要包括压实压溶作用、泥晶化、胶结、重结晶、白云石化、溶蚀和破裂作用。对储集岩起建设作用的主要是溶蚀、白云石化和破裂作用。 通过与同位于开江-梁平坳拉槽东段台地边缘浅滩相带上的普光、黄龙及盘龙洞地区的生物礁滩发育特征的对比,认识到峨眉地裂运动对于川东北地区生物礁滩组合相带的分布确实有控制作用,并具体分析了各地区生物礁、滩发育的特征,指出开江-梁平坳拉槽东段碳酸盐台地总体向北西倾斜,北部、西部地势低,南部、东部地势高。
[Abstract]:The reef beach assemblage of Changxing formation of Upper Permian is widely developed in the northeast of Sichuan Basin, and the reef beach assemblage is an important area of oil and gas reservoir rock development. Therefore, it is of great significance to study the distribution and development characteristics of the reef beach assemblage zone. As we all know, the distribution of sedimentary facies belt is controlled by tectonic movement, so the study of the relationship between the development and distribution of reef beach and Emei ground fissures movement can better guide oil and gas exploration. The reef of Changxing formation of Upper Permian in Tiechang River, Tongjiang River, is another representative of the reef found on the surface of Northeast Sichuan. Through the survey and detailed laboratory study of four profiles in the field, It is considered that there are reef and bioclastic shoal assemblage in Changxing formation in this area, and the round dune reef and shoal overlap to form the reef and beach complex with three cycles longitudinally. The reef-building organisms are mainly sponges, the content of which is 20% 鈮，

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