新型MEG钻井液体系的研究

A New MEG Drilling Fluid System

MEG钻井液是一种具有半透膜作用的水基钻井液,对页岩具有较好抑制作用。同时该体系又具有生物降解,保护环境的特点。阐述了MEG钻井液抑制页岩水化膨胀和分散的机理,研究并评价了MEG钻井液的性能及成膜效应。研究表明,MEG钻井液主要是通过成膜作用、渗透及去水化作用稳定页岩;具有较好的抑制性、润滑性和储层保护特性,钻井液性能稳定;在钻井液中浓度达到一定范围时,能在页岩表面形成半透膜,诱使页岩内的吸附水渗出。

MEG drilling fluid is a semi-membranceous water-base fluid and has good inhibition in shale,and it has the characteristics of biological degradation and environmental protection.The inhibiting hydration expansion and dispersion mechanism of MEG in shale is described.MEG performance and its membrane creation mechanism are studied and evaluated.The study indicates that shale is stabilized through membrance-making effect,pressure osmosizing and shale dehydrating effect,it has the characteristics of inhibition,lubrication and reservoir protection with stable performance in drilling fluid.When its concentration increases in a certain range,semi-membrance is formed on shale surface,inducing the water absorbed in shale to go into the drilling fluid.