Volume 57

Laboratory Cost-effective Methods to Evaluate CO2-Foam Behavior at Reservoir Conditions Zuhair AlYousef, Lei Ding, Amin Alabdulwahab, Lujain Alsiary

Abstract

Reducing CO2 emissions can be achieved through utilization of the less emitting energy resources as well as by increased consumption of the emitted CO2 through different applications including sequestering CO2 into subsurface formations. Deep subsurface formations such as depleted oil/gas reservoirs, basaltic formations, coal seam beds, and saline aquifers provide various opportunities for CO2 sequestration. One of the major challenges facing the CO2 injection is its poor volumetric sweep efficiency which is attributed to the low density and viscosity of injected CO2 compared to the reservoir fluids.
One promising method to improve CO2 sweep efficiency and, eventually, storage efficiency is the use of foam. Surfactants are mostly used to lower CO2-brine interfacial tension and generate foams. Usually high-pressure and temperature (HPHT) methods like core flooding are used to understand behavior of foams and foam producing chemicals at close to reservoir conditions, but unfortunately these methods are time-consuming and expensive to operate. The objective of this work is to evaluate foam behavior using HPHT robust surfactant screening equipment. These equipment include: foam rheometer (to study foam rheological properties), foam analyzer (to study certain foam characteristics such as bubble size and count, foam structure, and foam half-life), and microfluidics device (to understand the mechanisms and impact of added surfactants during CO2 and brine two phase flows in porous media in pore-scale level). They are capable of screening CO2 foam surfactant under reservoir conditions (HPHT) quickly and cost-efficiently. Several surfactants formulations are tested using those equipment. The selected chemicals are suitable for applications in high salinity and high temperature reservoirs.
Presented methods and laboratory equipment offer a significant advancement in the initial screening of foaming agents, especially when a large number of formulations need to be evaluated.

Keywords CCUS, CO2 Foam, Cost-Effective, Gas Mobility, Micromodel