逆冲断层发育区火山岩裂缝分布模式

准噶尔盆地车排子地区石炭系内发育有多条逆冲断层和多样的火山岩，且火山岩储层中构造裂缝发育。为了研究逆冲断层发育区火山岩裂缝分布模式，以车排子地区石炭系火山岩为例，分析了裂缝在纵向上和平面上的分布特征，并引入裂缝分布范围的“质心”概念，定量研究了裂缝分布范围在三维空间中的变化特征，提出了逆冲断层发育区火山岩裂缝分布模式。研究认为：裂缝空间分布范围变化特征有4种类型：质心正向偏移+密度值变大型（Ⅰ型）、质心负向偏移+密度值变大型（Ⅱ型）、质心正向偏移+密度值减小型（Ⅲ型）、质心负向偏移+密度值减小型（Ⅳ型）。逆冲断层发育区火山岩裂缝具有条带状楔形质心偏移模式，该模式特点为：平面上，裂缝分布形态呈现条带状；纵向上，裂缝分布形态呈现楔形，同时受到火山岩岩性的影响，局部裂缝的分布范围变大；裂缝分布范围的“质心”会在断层和火山岩岩性的控制作用下发生偏移。裂缝分布范围的“质心”概念的引入，可为裂缝分布规律的研究提供一种新的思路和方法。

Study on the fracture distribution pattern of volcanic rock in thrust fault developed zone

Thrust faults and volcanic rock are well developed in the Carboniferous Formation in Chepaizi area of Junggar Basin，and tectonic fractures are also well developed in volcanic rock reservoir.For studying fracture distribution pattern of volcanic rock in thrust fault developed zone，taking the Carboniferous volcanic rock in Chepaizi area for an example，the paper analyzes the distribution characteristics of fracture on the plane and longitudinal and quantitatively analyzes the changing characteristic of fracture distribution range in the three dimensional space by introducing the concept of center of fracture distribution.Then a distribution pattern is proposed.Results show that there are four changing characteristics of fracture special distribution range：center forward shift+greater density (typeⅠ)，center backward shift+greater density (type Ⅱ)，center forward shift+lower density (type Ⅲ)，center forward shift+lower density (type Ⅳ).And results show that a distribution pattern，named stripe wedge center-mobile，is proposed.There are three characteristics of pattern，including stripped distribution of fracture on the plane，wedged-shape and local expansion for lithology-lithofacies of fracture distribution on the longitudinal，and the center of fracture distribution comes to shift under the controlling of faults and volcanic rock.The introduction of concept of center of fracture distribution provides a new thought and method for the research on fracture distribution.