准噶尔盆地西北缘中拐凸起石炭系火山岩储层裂缝发育特征及主控因素

中拐凸起石炭系火山岩裂缝是该区火山岩储层的主要储集空间和渗流通道。该区火山岩储层发育有原生缝、次生缝及人工诱导缝等，其中以未充填或半充填的高角度剪切缝最为发育，为研究区的主要裂缝类型。该区裂缝方位主要为近NE向和近EW向，与现今最大主应力方向基本一致或呈锐夹角，有效性好。海西运动期是裂缝的主要形成时期。裂缝发育的影响因素主要包括构造部位、岩性及层厚等。岩性类型不同，裂缝发育程度也不同；裂缝的发育程度与构造位置密切相关，裂缝发育带主要沿断裂带呈条带状分布；由于火山岩普遍成层性差，层厚对裂缝发育的影响不明显。研究认为研究区裂缝发育的主控因素主要为岩性和构造位置。

Controlling Factors and Characteristic of Carboniferous Volcanic Reservoir Fractures of Zhongguai Uplift in Northwestern Margin of Junggar Basin

Carboniferous volcanic reservoir fractures are the main flowing channel and effective storage space for the reservoir in Zhongguai uplift.There are original fractures,secondary fractures and artificial induced fractures.High-angle unfilled or half-filled shear fractures develop best among them,which are the key types of factures.The main orientations of fractures are near N-E and E-W,which have good validity because of the consistent or sharp angle with the current maximum principal stress direction.The tectonic fractures are mainly formed in stage of Hercynian tectonic movement.The influence factors of the fractures development mainly include the tectonic position,rock types,rock stratum,and etc.The fractures in different lithology show different development degrees;there is a linear relationship between the develop degree of fractures and the tectonic position.Fracture-developed zone presents banded distribution along fault belt.Layer thickness plays less apparent effect on the fracture development because of poor stratification of volcanic reservoir.The tectonic position and rock type are the key controlling factors of fracture development.