Multi-Component Thermal Fluid Injection Performance in Recovery of Heavy Oil Reservoirs

Abstract

Field observations discern that the oil production rate decreases substantially and water cut increases rapidly with the increase of steam injection cycles. Compared with steam drive, the advantage of flue gas (also called multi-component thermal gas) co-injection with steam is that flue gas can increase the reservoir pressure and expand the heating chamber. In this paper, the flue gas generated by fuel burning in the field was injected with steam to improve heavy oil recovery. This technique was investigated in the large laboratory 3D model and implemented in the field as well. The huff-n-puff process efficiency by flue gas, steam, and flue gas–steam co-injection was compared in the experiments. The field practice also demonstrated that the addition of non-condensable gas in the steam huff-n-puff process recovered more oil than steam alone. The temperature profile in the wellbore with flue gas injection is higher than that with steam injection since the low thermal conductivity of N2 reduces the heat loss. With the increase of stimulation cycles, the incremental oil recovery by flue gas injection declines significantly.

Mechanism of Pressure Difference Variations on Heavy Oil Start-Up and Percolation Effects

“…As for development technology, microbial system oil recovery primarily reduces crude oil viscosity and oil–water interfacial tension by altering the properties of crude oil through metabolic products that lead to efficient percolation . The hot fluid system for oil recovery mainly improves the flow efficiency by heating crude oil, reducing its viscosity, dissolving and expanding it, and also maintaining formation pressure. , The polymer-based displacement control system enhances sweep efficiency and increases the oil–water contact area by obstructing high permeability channels, leading to efficient oil displacement . However, there are still some challenges that need to be addressed, such as developing high water consumption zones in the later stage of high water content, dealing with severe inefficient water circulation, finding ways to effectively utilize remaining oil in fault block reservoirs, injecting steam into deep and thin layers of ultraheavy oil, managing high heat loss, treating severe scaling in alkaline composite flooding oil systems, addressing stronger dynamic heterogeneity of reservoirs after polymer flooding, and dealing with more dispersed remaining oil …”