鄂尔多斯盆地南缘华北探区页岩油储层岩石力学特性实验研究
Experimental study on rock mechanical properties of shale oil reservoir in North China exploration,southern Ordos Basin
王翔 1冯永超1
作者信息
- 1. 中国石化华北油气分公司石油工程技术研究院,郑州 450000
- 折叠
摘要
针对鄂尔多斯盆地南部延长组7段页岩储层钻井过程中发生钻头适应性差和井壁垮塌等井下复杂状况,开展了岩石组构特征分析、力学特征分析和可钻性参数等力学特征分析.结果表明,鄂尔多斯盆地南缘页岩油储层中黏土以伊利石和伊/蒙混层为主,岩石结构及力学特性非均质性强.岩石表面层理结构明显,微裂缝和孔隙发育.页岩抗张强度为6.58～18.27 MPa,单轴抗压强度为76.79～169.29 MPa,高温下的内摩擦角为14.67°～36.71°,泊松比为0.167～0.352,主要集中在0.21附近,弹性模量为4 100～17 344 MPa.最小水平主应力梯度为1.89～2.14 MPa/100 m,最大水平主应力梯度为2.37～3.04 MPa/100 m,其中洛河地区最大、最小地应力梯度差值较大.地层可钻性级值为4.36～6.11,主要分布在5.5以下,属于软-中硬度地层,平均地层倾角小,在钻至水平段时,钻进方向与层理相同,与岩石接触面多互层,钻头磨损加重.基于页岩储层岩石力学特性认识,对于鄂南页岩油安全、高效地钻探具有指导意义.
Abstract
Aiming at the downhole complex conditions,such as poor adaptability of the drill bit and well wall collapse that occurred during the drilling process of shale reservoirs in the 7th Member of Yanchang Formation,southern Ordos Basin,the fabric characterization,mechanical characterization,and drillability parameter were analyzed.The research showed the clay of shale reservoirs is dominated by the ilmenite and ilmenite/monzonite mixed layer in the southern Ordos Basin,resulting in strong non-homogeneity of rock structure and mechanical properties.The rock surface lamina structure is prominent,and microfractures and pores are developed.The tensile strength of shale,the uniaxial compressive strength,and the internal friction angle at high temperatures are 6.58～18.27 MPa,76.79～169.29 MPa,and 14.67°～36.71°,respectively.The Poisson's ratios are 0.167～0.352,mainly concentrated in the vicinity of 0.21,and the elastic modulus is 4 100～17 344 MPa.The minimum horizontal principal stress gradi-ents are distributed in 1.89～2.14 MPa/100 m,the maximum horizontal principal stress gradients are distributed in 2.37～3.04 MPa/100 m,and the difference between the maximum and minimum ground stress gradients in Luohe area is large.The drillability grades of the formation are 4.36～6.11,mainly distributed below 5.5,and belong to soft-medium hardness formation.The average formation dip angle is small,and the drilling direction is the same as the bedding when drilling to the horizontal section,so most contact surfaces with the rock are interbedded,and the bit wear is aggravated.Understanding the rock mechanical properties of shale reservoirs has guiding significance for the"safe and efficient"drilling of shale oil in the southern Ordos Basin.
关键词
页岩油/延长组/页岩/岩石力学Key words
shale oil/Yanchang Formation/shale/rock mechanics引用本文复制引用
基金项目
国家科技重大专项(2017ZX05049)
出版年
2024
NETL
NSTL
维普
万方数据