四川盆地威远地区龙马溪组泥页岩储层非均质性

Shale reservoir heterogeneity of Longmaxi Formation, Weiyuan Area, Sichuan Basin

 潘涛¹ 姜歌² 孙王辉³

中国地质大学（北京）能源学院，北京 100083 中国石油新疆油田分公司风城油田作业区，新疆 克拉玛依 834000 中国石油新疆油田分公司准东采油厂，新疆 阜康 831500）

School of Energy Resources, China University of Geosciences, Beijing 100083, China Fengcheng Oilfield Operation Area, Xinjiang Oilfield Company, PetroChina, Karamay 834000, China Zhundong Oil Production Plant, Xinjiang Oilfield Company, PetroChina, Fukang 831500, China)

 在详细调研前人研究成果的基础上，结合四川盆地威远地区的实际地质情况，将泥页岩储层的非均质性分为宏观非均质性、微观非均质性和岩石力学非均质性3个方面。泥页岩储层的宏观非均质性主要体现在储层的横向展布、垂向上的岩性变化以及裂缝的分布特征。下志留统龙马溪组海相优质页岩的有效厚度普遍大于30 m，横向上厚度变化较小，均质性相对较好；垂向上泥页岩中普遍含砂质和灰质，部分层段几乎为粉砂岩，垂向非均质性非常明显；储层中裂缝主要发育在龙马溪组底部层段，具有极强的非均质性。微观非均质性主要受矿物组分和成岩作用的控制，其矿物组分、微孔隙和微裂缝的发育特征具有非常明显的非均质性。岩石力学非均质性主要包括泊松比、弹性模量、脆性和应力各向异性，是决定后期水力压裂措施和页岩气产量的关键。综合研究认为，四川盆地及其周缘龙马溪组页岩横向均质性较好，垂向非均质性、储层裂缝发育特征、微观非均质性以及岩石力学非均质性明显，对后期页岩气井的压裂和采收率的提高有重要影响。

 Based on the detailed investigation of predecessors′ research and the practical geological conditions of Sichuan Basin and its peripheral, shale reservoir heterogeneity is divided into three kinds: macroscopic heterogeneity, microscopic heterogeneity, and lithomechanics heterogeneity. The macroscopic heterogeneity is mainly instantiated in the horizontal distribution of reservoir, vertical change of lithology and fracture distribution characteristics. The effective thickness of marine high quality shale of Lower Silurian Longmaxi Formation is generally greater than 30 m and lateral thickness changes very slowly with good reservoir homogeneity. The shale Formation generally contains silty and grey matter, and part of the interval is almost siltstone with strong vertical heterogeneity. Fractures are mainly developed in the bottom of Longmaxi Formation with strong heterogeneity. Microscopic heterogeneity is mainly controlled by mineral components and diagenesis with obviously developed components, micro-porosity and micro-fractures. Lithomechanics heterogeneity, poisson′s ratio, young′s modulus, brittleness and stress anisotropy, determines hydraulic fracturing measures and shale gas production. Comprehensive analysis of Lower Silurian Longmaxi Formation shows that the good lateral uniformity, obviously developed vertical heterogeneity, fracture characteristics, microscopic heterogeneity and lithomechanics heterogeneity, have great effect on shale gas well fracturing and the recovery ratio of shale gas.

10.6056/dkyqt201604004