莺琼盆地重点区带深层储层岩石力学参数求取及意义

Calculation and Significance of Rock Mechanical Parameters of Deeply-buried Miocene Reservoir Rocks in the Key Offshore Exploration Blocks of the Yingqiong Basin,China

莺琼盆地中新统是油气勘探开发的重点层系,但海上区块深层储层取心极少,岩石力学参数研究较为薄弱。针对这种现状,文章基于声波全波列测井曲线,计算岩石动态力学参数;利用全岩矿物、物性分析以及压汞实验资料,分析岩石力学参数的影响因素。结果表明:研究区中新统储层杨氏模量介于20~50 GPa之间,泊松比介于0.1~0.35之间,内摩擦角介于20°~35°之间,抗张强度介于5~30 MPa之间。横向上,同一层位各岩石力学参数之间具有非均一性;垂向上,岩石力学参数与埋深呈弱正相关性。影响因素分析表明,岩石孔隙度、粘土矿物含量、脆性矿物含量以及孔隙半径影响岩石力学参数大小。研究成果一方面为该区地应力场模拟、储层裂缝评价以及目的层压裂优化设计提供了可靠的基础数据;另一方面,为衔接深部储层地质参数与地质力学参数评价提供了理论依据。

As the key target for oil and gas exploration and development in the Yingqiong Basin,the Miocene reservoir rocks are deeply buried in offshore blocks and have rarely been cored.Consequently,insufficient research has been implemented on their mechanical parameters.In this study,full-waveform acoustic logging curves are used to calculate the rock mechanical parameters of Miocene reservoir rocks.Specifically,whole-rock mineral analysis,physical property analysis,and mercury intrusion experiments are conducted to identify the key factors that influence the rock mechanical parameters.The Miocene reservoir rocks feature a Young’s modulus range of 20-50 GPa,a Poisson’s ratio range of 0.1-0.35,an internal friction angle range of 20°-35°,and a tensile strength range of 5-30 MPa.Laterally,heterogeneity of mechanical parameters is seen in the same layer.Vertically,these mechanical parameters present a weak positive correlation with the burial depth.Four factors are demonstrated to be crucial for rock mechanical parameters,namely rock porosity,clay mineral content,brittle mineral content,and pore radius.The results of this study provide reliable basic data for the simulation of insitu stress field,evaluation of reservoir fractures,and optimization of the target fracturing scheme.Moreover,the results of this study provide a theoretical basis for evaluation of geological and rock mechanical parameters of deeply buried reservoirs.