PREDICTION OF BOTTOMHOLE FORMATION ZONE UNDER ACTION OF DRILLING MUD Russian patent published in 2014 - IPC E21B47/00 E21B49/00 G01N15/08 

FIELD: oil-and-gas industry.

SUBSTANCE: proposed method comprises determination of drilling mud rheological properties, drilling mud filtrate and formation fluid, measurement of outer filtration crust, porosity and permeability of core specimen. Note here that mathematical model of said outer filtration crust if constructed. Drilling mud is forced through core specimen to register pressure drop dynamics at specimen and flow rate of effusing fluid. Micro tomography is used to define the profile of drilling mud solid particles penetrated into said specimen. Mathematical model of inner filtration crust is constructed to describe the dynamics of drilling mud particle concentration in threshold space of core specimen and associated changes in core specimen permeability. Enchained mathematical model of inner and outer filtration crusts is constructed. The latter allows the determination of parameters of inner filtration crust mathematical model whereat reproduced are experimental; data on pumping said drilling mud through core specimen and profile of drilling mud solid particles penetrated into said specimen.

EFFECT: higher accuracy and lower labour input.

1 cl, 8 dwg