南襄盆地泌阳凹陷陆相页岩油地质特征与评价

Geological characteristics and evaluation of continental shale oil in Biyang sag of Nanxiang Basin

南襄盆地泌阳凹陷中部深凹区发育有淡水环境及咸水环境沉积的深湖—半深湖相页岩。该套页岩岩相复杂、类型多、变化快,可分为泥质粉砂岩、粉砂质页岩、隐晶灰质页岩、重结晶灰质页岩及白云质页岩,总体富含有机质,这为陆相页岩油的形成提供了充分的物质基础。研究区页岩具有纵向厚度大、横向分布广、有机质丰度高及类型好、热演化程度适中、脆性矿物含量高及含油气性好等特征,具备良好的陆相页岩油形成条件。在明确泌阳凹陷具备良好的陆相页岩油形成条件基础上,进一步开展了陆相页岩油地质评价方法的研究,提出了一套包含岩石学分析、地质多参数综合评价、有利区带评价等8项关键技术的地质评价方法,并明确了泌阳凹陷陆相页岩油富集的主控因素及有利目标区,进而优化部署页岩油水平井,取得了中国陆相页岩油勘探的重大突破,展示了中国陆相页岩油良好的勘探开发前景。

In the central deeply-depressed area of Biyang sag in Nanxiang Basin, the organic shale was developed in semideep-deep lacustrine facies which were deposited in freshwater-saltwater environ- ments. The lacustrine shale had various kinds of complex lithofacies, and changed quickly. Totally, it could be divided into argillaceous siltstone, silty shale, aphanitic calcareous shale, recrystallization cal- careous shale and dolomitic shale. They were rich in organic matter, and offered a favorable material basis for continental shale oil. Biyang sag shale extended widely in large thickness, high content of organic mat- ters and better organic matter types, appropriate thermal evolution degree, high brittleness mineral content and petroliferous properties. Recent studies made it clear that Biyang sag had favorable formation condi- tions for shale oil. On this basis, the shale oil exploration and development technology were developed, including petrology analysis technology, geological multi-parameter comprehensive evaluation technology and the favorable zone evaluation technology. Moreover, the main controlling factors on the shale oil accu- mulation were determined and target area was predicted. The above research indicated that China＇s continental shale oil exploration had made significant breakthrough and demonstrated good exploration and de- velopment prospects of continental shale oil in China.