不同成因类型页岩气藏特征分析

The Characteristic Analysis of the Different Types of Shale Gas Reservoir

页岩气具有储层致密低渗,自生自储式成藏的特点,美国页岩气的成功开发是油气领域的新突破。2011年,美国页岩气产量超过1700×108m3,天然气基本实现自给,在一定程度上改变了世界天然气的供应格局。按照天然气的成因类型,页岩气可划分为热成因和生物成因两类。重点分析Barnett热成因页岩气藏和Antrim生物成因页岩气藏的地质特征和开发特征。我国已完钻页岩气井51口,其中直井37口,水平井14口;直井压裂试气15口,水平井压裂试气4口,14口见气;南方海相页岩气、四川盆地和鄂尔多斯盆地陆相页岩气勘探取得突破。通过我国南方海相热成因页岩气地质特征的对比分析,认为我国页岩气藏具有特殊性,储层条件更为复杂,美国页岩气开发技术不能完全适应我国页岩气的开发需求。另外,我国松辽和鄂尔多斯等盆地广泛发育富有机质页岩,但成熟度普遍偏低,热成因页岩气前景有限,但生物成因页岩气具有良好的成藏条件,是页岩气勘探的重点方向。

Shale gas reservoir is very tight with very low permeability and the gas generated from shale and stored in shale.The successful development of shale gas in the USA is a new breakthrough in the conventional oil and gas field.In 2011,the shale gas output has been more than 1700 ×108m3 in the USA.The natural gas has been realized self-supporting basically,and it changed supply framework of the international natural gas on certain degree.Shale gas can be divided into the thermogenic shale gas and biogenic shale gas.The geological and development characteristics of the thermogenic Barnett shale gas reservoir and the biogenic Antrim shale gas reservoir are analyzed.In China,51 shale gas wells are finished for drilling,among them,there are 37 vertical wells and 14 horizontal wells.Fifteen vertical wells and four horizontal wells are tested by fracturing with gas through in 14 wells.Exploration of marine shale gas in South China and continental shale gas in Sichuan Basin and Ordos Basin has breakthrough.Compared with the shale gas reservoir in the USA,the geological characteristics of the marine thermogenic shale gas in the South China are particularly different.The reservoir conditions are more complex,so the shale gas development technology in the USA can not totally adapt the conditions for the China shale gas.In addition,organic-rich shale spreads widely in the Songliao and Ordos and other basins with generally low maturity.So the thermogenic shale gas prospect is limited,but the conditions for biogenic shale gas accumulation are perfect and promising.