塔里木盆地库车前陆冲断带不同构造样式裂缝发育规律:证据来自野外构造裂缝露头观测

发布时间：2019-06-20 11:42

【摘要】：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。
[Abstract]:Natural fractures in reservoir have an important influence on oil and gas productivity, but because of the limited downhole data, it is generally difficult to determine the heterogeneity of fracture system distribution network by relying only on downhole data, and it is also difficult to obtain a large number of static parameters of fracture numerical simulation, so the quantitative evaluation of fractures is facing great challenges. The typical structural styles in the outcrop area of Kuqa Foreland thrust belt are selected to describe the unique fracture development and distribution characteristics under different structural styles (that is, thrust nappe monoclinic, high angle thrust compression anticlinal, basement occlusion slippage anticlinine), and to explore the law of fracture development under different structural styles. The results show that the thrust nappe monoclinic develops the second stage fracture, the strike is mainly north-west, mainly the late vertical opening joint, the early high angle oblique joint is semi-filled and fully filled by calcite, and the fracture surface density tends to decrease from the core to the wing. There are three stage cracks in the high angle thrust compression anticlinal, mainly in the north west direction and west direction. The early fractures are basically filled with calcite, the cracks are opened in the middle and late stage, and the single sand body is cut through and converges to the plane, which has obvious layer control. The steep wing cracks of anticlinal are stronger than those of slow wing, showing asymmetrical distribution law. The basement occlusive slip anticlinal is strongly squeezed by the first wing to develop two stage high angle oblique open fractures, and the fracture direction is north-west and east-east, and the deformation of blocked one-wing sandstone is weak, and no obvious cracks are found. The law of fracture development under different structural styles is of great significance to the numerical simulation of fractures and the prediction of favorable reservoir distribution.
【作者单位】：中国石油天然气股份有限公司杭州地质研究院;中国石油西南油气田公司重庆气矿;
【基金】：国家“十三五”重大科技专项(编号:2016ZX05003-001)资助
【分类号】：P618.13

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