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鄂尔多斯盆地沿河湾探区主力油层上三叠统延长组长61油层组属于特低渗透储层,其裂缝发育和分布状况成为制约油气勘探和有效开发的瓶颈。根据露头地层、钻井岩心及岩石薄片等实物资料,利用古地磁岩心定向方法,对沿河湾探区上三叠统延长组长61储层构造裂缝的基本特征、裂缝力学性质和裂缝有效性进行了定性—定量化观测统计。结果表明,沿河湾探区长61储层主要发育有区域性NEE向和近SN向高角度的共轭构造裂缝系统;储层段岩心构造裂缝密度为0.12~3.56条/m,以偏张性裂缝为主,充填较为严重,多为无效裂缝。依据长61岩心构造裂缝观测值,以有限元数值模拟方法为基础,岩石破裂法和能量法相结合,建立了长61储层构造裂缝分布定量预测数学模型。利用该模型预测了目的层裂缝相对发育区、次发育区和不发育区,并预测了张剪裂缝走向,为建立沿河湾探区长61储层裂缝分布网络模型和今后油气勘探、开发提供了地质依据。
The Chang-61 reservoir of the Upper Triassic Yanchang Formation in the Yanhewan exploration area, Ordos Basin, belongs to the ultra-low permeability reservoir. The development and distribution of fractures are the bottlenecks restricting oil and gas exploration and effective exploration. Based on the physical data of outcrops, drilling cores and thin rock slices, the authors used the geomagnetic core orientation method to study the basic features, fracture mechanics properties and fracture effectiveness of structural fractures of Chang 61 reservoir in Upper Triassic Yanchang Formation along Yanhewan exploration area Qualitative - quantitative observation statistics. The results show that the Chang 61 reservoirs in the Yanhewan exploration area mainly develop the conjugate structural fracture system with regional NEE and near SN high angle. The core structural fracture density in the reservoir section is 0.12 ~ 3.56 / m, Sexual cracks, filling more serious, mostly invalid cracks. Based on the observation data of Chang 61 core fracture and the combination of rock fracture method and energy method, a quantitative prediction mathematical model of structural fracture distribution in Chang 61 reservoir is established based on the finite element numerical simulation method. This model is used to predict the relative development zone, secondary development zone and undeveloped zone of the fracture in the target formation and predict the trend of the Zhang shear fracture. In order to establish the network model of fracture distribution in the Chang 61 reservoir along the Yanhewan exploration area and provide the future exploration and development of oil and gas Geological basis.