Modeling and designing the features of inflow to a horizontal gas borehole fitted with coiled tubing within the filtering interval

Abstract

Relevance. The need to study the parameters of inflow (permeability rates, production inflow profile, flow rate along the horizontal wellbore) into the horizontal gas and gas condensate wellbores, when  tubing is at the downhole zone. This allows scheduling well production rates, managing removal of water and mechanical impurities from the bottom-hole, carrying out well stimulation and completion activities, etc. Aim. To substantiate a mathematical model of the perforated horizontal gas borehole when the tubing shoe is within the perforation interval, as well as to calculate gas inflow parameters, flow rate along the wellbore and fluid permeability rates at the bottomhole zone of the wellbore. Object. Horizontal gas and gas condensate boreholes in anisotropic formations, methods for calculating gas inflow into perforated strings of horizontal boreholes, gas inflow rates and flow rates along the wellbore when tubing shoe is within the perforation interval. Methods. Modeling gas inflows into horizontal wellbores using a point source function, as well as the Leibenzon function; the use of local and hydraulic resistances theory in simulation of developing gas flow along the wellbore; determining gas inflow rates into the horizontal wellbore using the Reynolds number value. Results. The authors have carried out design calculation for the Bovanenkovskoe oil and gas condensate field using the model of gas inflow into a perforated horizontal (sloping) wellbore and analyzed the inflow parameters (flow velocity and permeability rates at the bottomhole zone, developing flow velocity along the wellbore) at various tubing shoe positions within the wellbore perforation interval. It was observed that when the tubing moves along the perforation interval the gas inflow to the wellbore can change from linear to non-linear. The authors made a conclusion that whenever extended periods of tubing positioning within the perforation interval is required, it is essential to select a low-pressure area which ensures a linear rate of gas inflow into the wellbore of a horizontal gas well.