Integrated sedimentary and high-resolution mineralogical characterisation of Ordovician shale from Canning Basin, Western Australia: Implications for facies heterogeneity evaluation
Integrated sedimentary and high-resolution mineralogical characterisation of Ordovician shale from Canning Basin, Western Australia: Implications for facies heterogeneity evaluation
复制标题
DOI：
10.1016/j.petrol.2021.109347
复制
发表时间：
2021-08-11
影响因子：
--
通讯作者：
Smith, Gregory
中科院分区：
文献类型：
--
作者：
Iqbal, Muhammad Atif;Rezaee, Reza;Smith, Gregory
认识页岩储层的相非均质性是页岩油气藏成功勘探和开发的关键。然而，页岩是一种非常细粒度的沉积岩，通过常规技术了解其非均质性具有挑战性。本文通过将岩心数据与高分辨率成像测井（SCMI）、岩相学信息、傅里叶变换红外（FTIR）和使用HyLogger 3采集的高光谱岩心反射光谱相结合的独特方法，解决了奥陶系Goldwyer地层（Goldwyer III页岩）面临的这一挑战。岩相学和FTIR数据验证了HyLogger 3作为检查页岩矿物学高分辨率垂直变化的工具的使用。结果表明，Goldwyer-III页岩在沉积特征、有机质丰度和矿物组成方面具有高度不均匀性。根据颜色、沉积特征、矿物成分和岩性，将所研究的页岩分为四个相。其相类型包括薄层状硅质页岩（TLSh）、结核状条带状钙质页岩（CSH）、块状黑色页岩（MBSh）和杂岩页岩（HSh）。总有机碳的变化从0.35至4.5重量%，由于相的变化，作为在缺氧-缺氧条件的波动的结果。TLSh、MBSh和HSh相具有相对较高的TOC值（高达4.5wt%）、T-max（高达450 ℃）、氢指数（高达250 mgHC/g）和脆性指数（>0.4）。而Csh相的TOC、Tmax、含氢指数和脆性指数最小。连续高分辨率高光谱岩心测井数据，结合岩相学和常规岩心测井，提供了一个更好的了解在Goldwyer-III页岩的非均质性。该研究为快速、连续、准确地识别水力压裂最佳相提供了一种新的工作流程。这种方法可以改善开发页岩气储层时的经济决策。基于TOC和矿物学衍生的脆性指数截止值，高品质的脆性区被识别在TLSh和HSh相沉积在中间（近端到远端）沉积环境。
An understanding of the nature of the facies heterogeneity is crucial for successful exploration and development of shale reservoirs. However, shale is a very fine-grained sedimentary rock and it is challenging to understand its heterogeneity through conventional techniques. This paper addresses this challenge for Ordovician Goldwyer Formation (Goldwyer-III shale) through a unique approach by integrating core data with high-resolution image logs (SCMI); petrographic information; Fourier transform infrared (FTIR); and hyperspectral drill core reflectance spectra acquired using a HyLogger3. The petrographic and FTIR data validates the usage of HyLogger3 as a tool to examine high-resolution vertical variations in the shale mineralogy. The results indicate that the Goldwyer-III shale is highly heterogeneous in terms of sedimentary features, organic richness and mineral composition. The studied shale is divided into four facies based on colour, sedimentary features, mineral composition and lithology. The facies include thinly laminated siliceous shale (TLSh), concretionary-banded calcareous shale (CSh), massive black shale (MBSh) and heterolithic shale (HSh). The total organic carbon varies from 0.35 to 4.5 wt% due to variation in facies as a result of fluctuation in oxic-anoxic conditions. The TLSh, MBSh and HSh facies have a higher TOC value (up to 4.5 wt %), T-max (up to 450 degrees C), hydrogen index (up to 250 mgHC/g) and brittleness index (>0.4) comparatively. Whereas, the CSh facies has least TOC, Tmax, hydrogen index and brittleness index. Continuous high-resolution hyperspectral core log data, combined with petrography and conventional core logging, provides a much better understanding of heterogeneity in Goldwyer-III shale. This study offers a new workflow for rapid, continuous and accurate recognition of optimum facies for hydraulic fracturing. This approach can improve economic decisions when developing shale gas reservoirs. Based on TOC and mineralogical derived brittleness index cut-offs values, the high-quality brittle zones are recognised in TLSh and HSh facies deposited in medial (proximal to distal) depositional setting.