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南海白云凹陷深水区渐新世-中新世沉积特征对深水油气勘探具有非常重要的意义,中新世发育的陆架边缘三角洲与南海陆坡深水沉积体系有特殊的三级“源-汇”响应关系.研究基于近期新钻井、精细三维地震资料解释,进一步揭示了陆架边缘三角洲的形成、演化,及其对陆坡深水重力流沉积形成的“源”控作用.渐新世该陆架边缘三角洲主要形成于层序低位期晚期,以三角洲前缘沉积为主,在陆架断阶坡折控制下呈“S”型向陆坡生长.中新世自外陆架到上陆坡的延伸空间内,沉积机理发生改变,由牵引流向重力流发生变化,在白云凹陷内形成陆坡复合水道、重力流沉积,并有东沙隆起的碳酸盐岩短轴物源耦合,形成双(多)物源控制的混合沉积.这种沉积演化特征受控于陆架边缘三角洲发育和陆架断阶坡折带的演化,形成陆架边缘三角洲和深水储集体特殊分布.因此,白云凹陷深水区油气勘探要注重陆架边缘三角洲形成、演化、分布及其与深水沉积体三级“源-汇”响应.
The Pliocene-Miocene sedimentary features in the deep-water area of the Baiyun Sag in the South China Sea are of great significance to deepwater oil and gas exploration. There are three special stages of “source-sink” in the deep-water sedimentary system of continental shelf continental margin and South China Sea continental shelf developed in the Miocene. Response.Researching the formation and evolution of marginal deltas and their “source ” control effect on the formation of deep-water gravity flow deposits on the continental slope based on the recent new drilling and fine three-dimensional seismic data interpretation, further revealed that the Oligocene shelf margin The delta was mainly formed in the late low-stage sequence and was mainly deposited in the delta front, and was “S” -shaped to the slope slope under the control of continental shelf slope collapse. From the Outer shelf to the extension of the upper slope , The depositional mechanism changed from traction flow to gravity flow, and the slope complex channel and gravity flow sedimentation were formed in Baiyun sag. Coupling with the short-axis carbonates in the Eastern Shahekou uplift, a dual (multi-source) source control This sedimentary evolution is controlled by the evolution of continental shelf margin deltas and continental slope fault break-offs, resulting in the special distribution of delta margin and deep-water reservoir on shelf margin. Therefore, the Baiyun sag Oil and gas exploration in deepwater areas should pay attention to the formation, evolution and distribution of the marginal deltas of the shelf and its response to the “source-sink” response of the deep-water sediments.