新疆石油地质 ›› 2024, Vol. 45 ›› Issue (5): 595-603.doi: 10.7657/XJPG20240512

• 应用技术 • 上一篇    下一篇

基于改进型随机森林算法的页岩岩性识别——以准噶尔盆地芦草沟组为例

秦志军1,2(), 操应长1, 冯程3   

  1. 1.中国石油大学(华东) 地球科学与技术学院,山东 青岛 266580
    2.中国石油 新疆油田分公司 勘探开发研究院,新疆 克拉玛依 834000
    3.中国石油大学(北京)克拉玛依校区 石油学院,新疆 克拉玛依 834000
  • 收稿日期:2024-07-24 修回日期:2024-08-12 出版日期:2024-10-01 发布日期:2024-10-09
  • 作者简介:秦志军(1973-),男,河南鹿邑人,高级工程师,油气地质,(Tel)13999317701(Email)qinzj@petroleum.com.cn
  • 基金资助:
    国家自然科学基金(42364007);国家自然科学基金(42004089);新疆维吾尔自治区自然科学基金(2021D01E22)

Shale Lithology Identification Based on Improved Random Forest Algorithm:A Case of Lucaogou Formation in Junggar Basin

QIN Zhijun1,2(), CAO Yingchang1, FENG Cheng3   

  1. 1. School of Geosciences, China University of Petroleum (East China), Qingdao, Shandong 266580, China
    2. Research Institute of Exploration and Development, Xinjiang Oilfield Company, PetroChina, Karamay, Xinjiang 834000, China
    3. College of Petroleum, Karamay Campus, China University of Petroleum (Beijing), Xinjiang 834000, China
  • Received:2024-07-24 Revised:2024-08-12 Online:2024-10-01 Published:2024-10-09

摘要:

在储集层岩性识别的应用中,特别是对页岩等非均质性较强的非常规储集层的岩性识别,机器学习算法的高效性、准确性和有效信息整合能力已经得到了充分验证。考虑到岩性识别的特征参数优选问题,优选自然伽马、T2几何平均值、结构指数、骨架密度指数、密度和深侧向电阻率,采用结合递归特征消除的随机森林算法,对准噶尔盆地中二叠统芦草沟组页岩储集层的主要岩性进行识别;利用传统的随机森林算法和支持向量机法,对同一套资料进行岩性预测,并与岩石薄片鉴定结果对比。结合递归特征消除的随机森林算法只需选择一半的测井参数,便能够达到更好的效果,而且通过优选特征参数,缩短了算法的运行时间。因此,结合递归特征消除的随机森林算法能够实现测井特征参数的优选,提高页岩岩性识别的准确率,缩短运行时间,为复杂岩性识别和多参数选择提供了新的思路。

关键词: 随机森林算法, 递归特征消除, 特征选择, 中二叠统, 芦草沟组, 页岩储集层, 岩性识别

Abstract:

In the application of reservoir lithology identification, the efficiency, accuracy and effective information integration ability of machine learning algorithm have been fully verified, especially in unconventional reservoirs with strong heterogeneity such as shale. Based on the optimal selection of parameters such as natural gamma, T2 geometric mean, structural index, skeleton density index, density, and deep lateral resistivity, and using a random forest algorithm combined with recursive feature elimination (RF-RFE), major lithologies of the shale reservoirs in the Middle Permian Lucaogou formation in the Junggar basin were identified. Lithology prediction was conducted on the same dataset using conventional RF and support vector machine (SVM) algorithms, and the results were compared with those obtained from thin-section identifications. It is found that RF-RFE yields better results with only half of the logging parameters, and the parameters defined by optimal selection help reduce the algorithm’s running time. Thus, the use of RF-RFE algorithm can realize optimal selection of characteristic logging parameters, more accurate identification of shale lithology, and reduction of running time. The algorithm provides a new approach for complex lithology identification and multi-parameter selection.

Key words: random forest algorithm, recursive feature elimination, optimal selection, Middle Permian, Lucaogou formation, shale reservoir, lithology identification

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