Experimental Study of the Feasibility of Air Flooding in an Ultra-Low Permeability Reservoir

Abstract

Abstract:The development effect of water flooding in an ultra-low permeability reservoir is poor due to its poor physical properties and high shale content, so an experimental study of air flooding which helps to complement energy production was carried out. Based on the Accelerating Rate Calorimeter experimental results, the crude oil of N block in L oilfield can undergo low-temperature oxidation reactions, which are the basic condition for air flooding. Three groups of experimental natural cylinder cores designed for oil displacement, water flooding and air flooding were used respectively, and the relationship between differential pressure, oil recovery, injection capacity with injection volume was investigated. It is observed that the recovery efficiency increased 2.58%, the injection-production pressure difference dropped 60% and the injection capability increased 60% in the experiment of shifting air flooding after water flooding to 75% moisture content, compared with water flooding alone. It has been shown in the results that the recovery efficiency improved sharply more than water flooding, the effect of depressurization and augmented injection was obvious, and the air displacement was thus validated. We suggest that other science and technology workers should perform further tests and verify this result through numerical simulation.

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“…The ultra-low permeability reservoirs are important parts of unconventional oil and gas resources; there are great challenges in exploitation and utilization. Compared with conventional reservoirs, ultra-low permeability reservoirs have the characteristics of low porosity, low permeability, and poor connectivity (Zhao et al 2014;Qu et al 2016;Qiao et al 2017;Peng et al 2018;Zhang et al 2019;Wang et al 2019). It has become a decisive problem restricting the development of ultra-low permeability oil and gas resources.…”