泥页岩水化对岩石力学强度的影响

The Experimental Study of Effect of Shale Hydration on Rock Mechanics Strength

泥页岩经过水溶液浸泡,会因水化作用而膨胀,造成抗压强度、黏聚力、岩石强度及井壁稳定性下降,进而引起井壁失稳问题。进行单轴抗压试验和单轴抗拉试验,在不同离子类型及浓度的水溶液条件下,研究泥页岩的弹性模量、泊松比、破裂时的最大载荷值以及部分岩心的抗拉强度的变化趋势。实验结果表明在相同的试验条件下,泥页岩水化程度与钻井液类型有关,氯化钾钻井液对泥页岩的抑制作用最好。

When the Shale being soaked by aqueous solution,rock expands because of the effect of hydration.As a result,the compressive strength reduces and cohesion decline,so rock strength decreases,and the wellbore stability decreases,which would cause borehole instability problem.In this paper,uniaxial compression test and uniaxial tensile test would be operated when the rock is socked with the aqueous solution under various concentrations of different ion types.The variation trend would be studied including shale elastic modulus,poisson＇s ratio,maximum load value when the rock collapses,and the tensile strength of the part of the core.In the same experimental conditions,the shale hydration degree related to the type of drilling fluid,potassium chloride drilling fluid have the best ability of inhibition.In drilling engineering,different ion typesof drilling fluid systems provide a reference to the controlling shale hydration.