Experimental and computational evaluation of cyclic solvent injection in fractured tight hydrocarbon reservoirs

Abstract

Multi-fractured horizontal wells have enabled commercial production from low-permeability (‘tight’) hydrocarbon reservoirs but recoveries remain exceedingly small (< 5–10%). As a result, operators have investigated the use of solvent (gas) injection schemes, such as huff-n-puff (HNP), to improve oil recovery. Previous HNP laboratory approaches, classified primary as ‘flow-through-matrix’ and ‘flow-around-matrix’ typically (1) are not fully representative of field conditions at near-fracture regions and (2) require long test times, even when performed on fractured cores. The objectives of this proof-of-concept study are to (1) design and implement a new experimental procedure that better reproduces HNP schemes in near-fracture regions and (2) use the results, simulated with a compositional lab-calibrated model, to explore the controls on enhanced hydrocarbon recovery in depleted tight oil plays. Performing multiple CO2 and (simplified) lean gas HNP cycles, the integrated experimental and simulation approach proposed herein achieves the ultimate recovery factors in a significantly shorter time frame (25–50%) compared to previous studies. The integrated experimental and computational approach proposed herein is valuable for core-based evaluation of cyclic solvent (CO2, CH4) injection in tight hydrocarbon reservoirs for (1) hydrocarbon recovery and (2) subsurface greenhouse (CO2, CH4) gas disposal/storage applications.

Oil Production Mechanism of Water Injection Huff-n-Puff for Enhancing Oil Recovery in Tight Sandstone Reservoir

“…There are significant recoverable oil and gas resources stored in tight reservoirs throughout the world. Horizontal well multistage cluster fracturing technology has achieved commercial production of low permeability (ultralow permeability) oil and gas reservoirs, but recoveries remain exceedingly small (<5–10%). , For tight oil cores, more than 80% of the pores are submicrometer and micro nanopores. More than 77.8% of crude oil exists in submicropores and micropores, and movable fluid mainly exists in micropores with radii greater than 1 μm. , The development of water flooding operations in tight oil reservoirs is not satisfactory. , …”

Experimental Study on Polymer flooding-assisted CO2-based Cyclic Solvent Injection Process for Enhancing Oil Recovery in Heavy Oil Reservoirs

“…The CSI process involves circulating a specific solvent into the reservoir to displace the oil and improve the recovery factor [3]. Compared with the previous mentioned three development methods, CSI process effectively overcomes the above-mentioned shortcomings, and has the following advantages: 1) Many previous studies have proven that the CSI process has excellent ability to improve oil recovery because of foamy oil flow [17][18][19].…”

Experimental Investigation of Factors Influencing PVT Behavior in CO2-Oil-Brine System

“…Due to depletion of conventional petroleum resources, CCUS in unconventional reservoirs, especially tight reservoirs with considerable petroleum reserves was then developed [9], [10], [11]. Multi-scale investigations (from pore to reservoir scale) were designed and conducted through various methods mainly including laboratory experiments and numerical modeling [12], [13], [14], [15], [16]. Such investigations contributed to effective injection strategies, accurate evaluation systems, and reliable predictions [13], [17], [18], [19].…”