塔里木盆地麦盖提斜坡东段油气勘探前景

HYDROCARBON EXPLORATION PROSPECTS IN THE EAST SECTION OF THE MAIGAITI SLOPE IN THE TARIM BASIN

塔里木盆地麦盖提斜坡东段具有油气成藏的有利条件,本区发育的寒武—奥陶系的烃源岩和一套高丰度的石炭系油源岩,为该区形成大油气田提供了物质基础。发育以奥陶系潜山风化壳为储层、志留系泥岩以及石炭系下泥岩段为盖层和以石炭系砂砾岩段、生屑灰岩段作储层、下泥岩段及中泥岩段为盖层的多套储盖组合。储层分布稳定,储集条件良好,盖层保存完好,良好的储盖条件为油气富集创造了条件。麦盖提斜坡经历了寒武—奥陶纪北倾斜坡和自石炭纪以来南倾斜坡的发展过程,处在构造活动的枢纽部位,既有利于油气聚集更有利于油气的后期保存,是有利的油气聚集成藏区。麦盖提斜坡东段具有良好的油气远景,奥陶系碳酸盐岩岩溶圈闭、石炭系构造及地层岩性圈闭应为进一步勘探的主要对象。

It was considered that the east section of Maigaiti Slope in the Tarim Basin had the favorable conditions for hydrocarbon accumulation. Cambro-Ordovician hydrocarbon source rocks and a set of carboniferous oil source rocks with high abundance which develop in this area provide material foundations for the formation of large oil/gas fields in this area. There are several reservoir-seal assemblages in the Maigaiti Slope. One is the assemblage of Ordovician weathered crust of the buried hill as reservoir bed, and Silurian mudstone and Carboniferous lower mudstone member as seals. The other is the assemblage of the Carboniferous glutenite member and bioclast limestone member as reservoir bed, and low mudstone member and medium mudstone member as seals. Reservoir beds with favorable reservoir condition are distributed stably, and seals are in perfect condition. Favorable reservoir-seal asseinblages provide favorable foundation for hydrocarbon enrichment. Maigaiti Slope experienced development processes of north dipping slope during Cambro-Ordovician and south dipping slope since Carboniferous period, and is located at pivot part of the tectonic movement, which is favorable for the hydrocarbon accumulation and the later storage. It is a favorable area for the hydrocarbon accumulation and reservoir with favorable hydrocarbon prospects. It is predicted that Ordovician buried hill and Carboniferous anticline reservoir in the east section of Maigaiti Slope should be the main objects for the further exploration.