Understanding diffusion-controlled bubble growth in porous media using experiments and simulations

Nucleation and subsequent growth of gas bubbles inside liquid reservoirs is believed to be one of the production mechanisms taking place during oil recovery from tight oil reservoirs. Depleting reservoir pressure results in the nucleation of bubbles from the dissolved gas inside the liquid. These bubbles grow as dissolved gas molecules inside the oversaturated liquid diffuse to the gas-liquid interface. At this stage, the principal drive mechanism for production is the expulsion of liquid due to expansion of bubbles inside the pores. We built an experimental setup using microfluidic chips to study the dynamics of bubble growth in porous media. We show that rate of bubble growth and invasion pattern of growing bubbles depend on the saturation of the liquid solution. A nonlinear pore-network model from the literature is implemented to simulate bubble growth. We compare model predictions for bubble growth dynamics to our experimental results and present the need for further theoretical development to capture deviations from invasion-percolation when a large pressure drop is applied.