哈拉阿拉特山石炭系裂缝发育特征及成藏意义

Characteristics of the Carboniferous Volcanic Fractures and Its Hydrocarbon Accumulation Significance in Hala′alate Mountains

哈拉阿拉特山地区位于准噶尔盆地西北缘前陆褶皱冲断带,紧邻玛湖生烃凹陷,是油气运移和聚集的有利区域。针对该区石炭系油气藏主要赋存于火山岩构造裂缝中且富集规律不清楚的问题,开展了构造裂缝的发育特征、控制因素及其与油气成藏的关系研究。利用钻井岩芯、成像测井、岩石力学实验及流体包裹体分析等手段,研究了石炭系火山岩构造裂缝的产状、密度、发育次序、主控因素及其与油气成藏关系。结果表明,石炭系火山岩裂缝主要为高角度裂缝,裂缝发育的优势倾向为北西—南东向,影响裂缝发育的主控因素为岩石力学性质及所处的构造位置。同时,由于高角度缝充填程度低、形成时间晚、发育程度高,且与油气主要的运移成藏期匹配较好,因而成为研究区石炭系油气主要勘探目标。该研究结果对于哈拉阿拉特山地区石炭系火山岩油气藏的勘探与开发具有重要的指导意义。

Hala′alate Mountains Area,situated in the foreland fold thrust belts of the northwestern margin of Junggar Basin, adjacent to hydrocarbon generation depression of Mahu,is a favorable area of hydrocarbon migration and accumulation. Car-boniferous hydrocarbon reservoir in this area was mainly hosted in the volcanic tectonic fractures and its enrichment regulation was unknown. Aiming at this problem,we study the development characteristics,controlling factors of tectonic fractures and its relationship with hydrocarbon accumulation. By using drilling core,imaging logging,rock mechanics tests and fluid in-clusion analysis technics,the paper studied the attitude,density,developing order,main controlling factors of Carboniferous volcanic tectonic fractures and their relationship with hydrocarbon accumulation. The results show that the cracks in carbonif-erous volcanic rocks are mainly high angle cracks,and the advantage fracture development tendency is northeast-southwest;the main controlling factors are rock mechanics properties and structural position. Besides,due to the low filling rate,late forming time and well matching with the major hydrocarbon migration and accumulation,the high angle fractures became the main hydrocarbon exploration area. The results have very important guiding significance for the exploration and development of Carboniferous volcanic hydrocarbon reservoir in Hala′alate Mountains Area.