Experimental investigation for the dynamic adsorption behaviors of gel system with long slim sandpack: Implications for enhancing oil recovery

Abstract

The retention of gel system in porous media results in the reduction of porosity and permeability. However, the length of the current experiment models (sandpack or core sample) are in the range of centimeter scale, which is too short to track the full movement path of gel particles. In this work, a series of gel flooding experiments were conducted on 2.5-m long slim sandpack models. Seven fluid collection/pressure monitoring points were equally distributed along the length of the slim sandpack to track the movement of gel particles during the flooding process. We quantified the adsorption capacity, adsorption velocity, and mechanical shear effect of polymer/cross-linking agent along the flowing direction. In addition, we also employed scanning electron microscope (SEM) equipment to observe the morphology of the gel and the pore structure along the flooding direction, which provides good evidences of the adsorption retention and mechanical shear effects. Results show that most of the polymers and cross-linking agent were adsorbed on the region near the inlet. We emphasized the advantages of using long sandpack/core to track the full movement path of the gel system. In addition, the morphology of the original gel system showed a network characteristic of hexagonal structure, which was dragged to an elongated structure or even totally broke when it was transported through the porous medium. This work provides the fundamental understandings of the dynamic adsorption behaviors of gel system, which could be useful for optimizing the components of gel system, selection of target oil reservoirs and their operational parameters during gel flooding in enhancing oil recovery.

Keywords

• Enhancing oil recovery
• Gel system
• Adsorption
• Experiments
• Long slim sandpack