储层中的天然裂缝对油气产能有重要影响,但由于井下数据有限,仅依靠井下数据一般难以确定裂缝系统分布网络的非均质性,同时也难以获取裂缝数值模拟大量的静态参数,因此对裂缝的定量评价面临着较大挑战。选取库车前陆冲断带露头区典型构造样式,描述不同构造样式下(即逆冲推覆单斜、高角度逆冲挤压背斜、基底遮挡滑脱型背斜)独特的裂缝发育分布特征,探讨不同构造样式下的裂缝发育规律。结果表明:逆冲推覆单斜发育2期裂缝,走向主要为北北西向,以晚期近直立开启缝为主,早期高角度斜交缝被方解石半充填—全充填,裂缝面密度自核部向翼部有降低趋势;高角度逆冲挤压背斜总体发育3期裂缝,以北北西向、北西西向为主,早期裂缝基本被方解石完全充填,中晚期裂缝开启,且切穿单砂体并收敛于层面,具有明显层控性,背斜的陡翼裂缝较缓翼发育强烈,呈现出不对称的分布规律;基底遮挡滑脱型背斜被强挤压一翼发育2期高角度斜交开启缝,裂缝方向呈北北西向和北东东向,被遮挡一翼砂岩遭受变形较弱,基本未见明显裂缝。不同构造样式下的裂缝发育规律对裂缝数值模拟和有利储层分布预测均具有重要意义。
Natural fracture in reservoir has important influence on oil and gas production.It is difficult to de-termine the distribution of fracture network’s heterogeneity only rely on limited downhole data.In addi-tion,it is also difficult to obtain a large number of the static parameters for fracture numerical simulation, so the quantitative evaluation of fracture faces greater challenge.Based on typical tectonic styles of Kuqa foreland thrust belt outcrop area (which include thrust monoclinic,high angle thrust anticline and slip anti-cline),this article described the fracture unique development and distribution characteristics of different tectonic styles,then established the fractures development models of different tectonic style,finally ana-lyzed the controlling factors on fracture growth.The results show that the thrust monocline fold develops two phases fractures,the strike direction are NNW mainly.Late vertical open fractures have absolute priori-ty in this tectonic style,and early high angle oblique fracture is filled by calcite.The density of fracture from core of anticline to wing has decreasing tendency.High angle thrust anticline develops three phases fracture,and the strike direction is NNW and NWW.The early fracture was full filled by calcite,middle-late fracture are opened.The fracture cut off the single sand body and converges to rock bed,which have obvious mechanical stratigraphic characteristics.The steep wing of anticline’s developed more tectonic fractures than that of slower wing,which shows asymmetric distribution.The compression wing of slip anticline de-velops two stage high angle oblique open fracture,and the fracture strike direction is NNW and NEE.The sandstone deformation of barrier wing is weak in which it doesn’t have obvious fracture development.The fracture growth characteristics under different structural styles are of great significance to the numerical simulation of fracture and the prediction of reservoir distribution.