秦南凹陷陡坡带源—汇输砂体系定量研究

QUANTITATIVE STUDY ON THE SOURCE-SINKING SAND TRANSPORTING SYSTEM IN THE STEEP SLOPE OF QINNAN SAG

为搞清秦南凹陷陡坡带输砂能力的控制因素,利用钻井及三维地震资料,结合勘探实践,应用源—汇理论,对秦南凹陷北部陡坡带源区输砂体系的类型、成因及输砂能力进行了探讨。研究表明:研究区发育断槽型(单断、双断)、侵蚀沟谷型(溯源侵蚀型、河流下切型)、山间洼地型和盆内转换带型4种输砂体系类型;东侧发育河流下切型和断槽型输砂体系,西侧古近纪早期发育溯源侵蚀沟谷型输砂体系,后期遭受充填,为沉积体系提供可容空间;输砂体系中河流下切型输砂能力最强。受输砂体系的影响,汇区的古近系沉积体系规模东侧大于西侧,东侧汇水充足,储层物性好,是下部勘探有利区。

In order to make clear of the controlling factor of the sand transporting capacity in the steep slope of Qinnan Sag, with the help of the drilling, 3D seismic data and source-sinking theory, and moreover integrating with the exploratory practice, the types, causes and the sand transporting capacity in the source area of North Steep Slope of Qinnan Sag were analyzed. The research results show that four types of the transporting system are devel- oped in the study area： faulted trough type （single and double faults） , erosion valley type （ source-traceable erosion type and river downcut type ）, intermountain low type and inner-basin transforming belt type ; the river downcut type and faulted gene of the west system ; the sand porting systems, trough type exist in the east area, while the source-traceable erosion type existed in Early Paleoarea, and filled in Late Paleogene, thus the accumulating space was provided for the depositional transporting power is the strongest for the river downcut type system. Influenced by the sand trans- Paleogene sedimentary system in the east part of the collecting area is larger than that in the west side, and abundant in the collected water and furthermore the reservoir physical properties are much better, so the region has become the favorable block of the future exploration.