油气地质与采收率2025，Vol.32Issue(3)：68-77,10.DOI:10.13673/j.pgre.202406048
陡坡型台缘生物礁沉积特征及影响因素
Sedimentary characteristics and influencing factors of steep slope platform-margin reefs:A case study of Changxing Formation in Kaijiang-Liangping Trough in northeastern Sichuan Basin
摘要
Abstract
Gentle and steep slope platform-margin reefs are well-developed in the Changxing Formation in the Kaijiang-Liangping Trough in the northeast Sichuan Basin.At present,there is less research on the sedimentary structure and evolution model of steep slope platform-margin reefs.The exploration and development of oil and gas reservoirs in the area are restricted.Based on seismic,logging,and drilling data,the internal structure,external profile,and planar distribution characteristics of the steep slope platform-margin reefs of the Changxing Formation were systematically compared.The evolution models and influencing factors of these steep slope platform-margin reefs were discussed.The results show that the steep slope platform-margin reefs of the Kaijiang-Liangping Trough can be divided into fault-controlled steep slope type and sedimentary steep slope type.The external contour of the fault-controlled steep slope platform-margin reef shows a significant symmetry.The deposition thickness is approximately 100-200 m,and there is no lateral migration phenomenon.Moreover,it is mainly distributed in discontinuous and strip-like patterns on the plane.The width of the slope zone at the platform-margin is approximately 1.3-1.9 km.The external contour of the sedimentary steep slope platform-margin reef is asymmetrical.The deposition thickness is approximately 40-120 m,and lateral migration can be observed.It is distributed discontinuously and star-like on the plane.The width of the slope zone at the platform margin is approximately 2.0-2.5 km.The fault-controlled steep slope platform margin reefs have significant differences from the sedimentary steep slope platform-margin reefs in terms of sea level change,paleogeomorphic features,and paleoenvironmental conditions due to the occurrence of synsedimentary fault activities.It leads to obvious differences between the two in terms of external contours,structure,and distribution.Through comprehensive analysis of stratigraphy,paleogeomorphology,and sedimentary facies of the steep slope platform-margin reefs of the Changxing Formation in the Kaijiang-Liangping Trough,the differential evolution models of the three stages of the reef have been established.The adjustment period of Longtan Formation:with the rise of sea level,the environmental conditions are changed,which paves the way for the growth and development of the reef;stable growth period of Changxing Formation:at this time,there are the best environmental conditions for the survival of reef-building organisms,and the reefs develop rapidly;decline period of Changxing Formation:The reef continues to grow and begin to expose the water surface,leading to dolomitization and decline.关键词
生物礁/陡坡型台缘/长兴组/演化模式/四川盆地Key words
reef/steep slope platform-margin/Changxing Formation/evolution model/Sichuan Basin分类
石油、天然气工程引用本文复制引用
黄宇炫,陈旭,武赛军,魏军红,王敬原..陡坡型台缘生物礁沉积特征及影响因素[J].油气地质与采收率,2025,32(3):68-77,10.基金项目
南方复杂页岩油气地质与开发湖北省重点实验室开放基金项目"陆相断陷湖盆页岩油断缝体定量化表征及成因机制"(SSOG202401),地质过程与矿产资源国家重点实验室开放基金项目"挤压环境脉冲式构造波动幕及油气差异富集"(GPMR202207),大陆动力学国家重点实验室开放基金项目"挤压坳陷湖盆脉冲式构造波动幕及沉积协同演化"(22LCD20). （SSOG202401）
