Microfluidic chips for oil recovery from carbonate reservoirs at elevated temperatures

Literature reviews on the low salinity effect in core flooding and the emergence of microfluidics in IOR underline the importance of the development of microfluidic micromodels to better mimic core flooding experiments. Even though many microfluidic microchannels on improved oil recovery have been developed in the past, a micromodel to better represent the 3D features of pore structures, geochemistry of carbonate and waterflooding conditions similar to real carbonate reservoirs is still missing. One of the main reasons is that fabrication of 3D micromodels with arbitrary and high-resolution porous structure is still challenging. Another challenge is to represent all relevant aspects of the complexity of the real system such as geometry and aging protocols at reservoir relevant conditions while still being able to quantify the efficiency of the IOR process and to identify important microscopic processes. In addition, incorporation of calcite material into a micromodel is also difficult due to the complex properties of carbonate material and its stability during the coating process. The overall goal is to incorporate all these properties to closely mimic the condition of carbonate reservoirs. In this thesis, micromodels mimicking 3D features of porous media are developed via a 3D packed bed of calcite particles, a 2.5D glass micromodel and a 2.5D calcite coated micromodel with dual depth. The effects of fluid aging, calcite coating, brine composition and reservoir temperature on the physicochemical properties of the 2.5D micromodels and crude oil fraction in the pore space are studied. Furthermore, image analysis tools to quantify the oil recovery and obtain insight into the oil extraction process are also developed. These findings contribute to the ongoing development of microfluidic micromodels to study the waterflooding oil recovery in carbonate reservoirs.