Improving sweep efficiency of edge-water drive reservoirs using induced formation damage

Comprehensive evaluation of waterflooding front in low‐permeability reservoir

“…Fenglan et al 5 pointed out that carbon dioxide flooding is an effective method to improve the oil recovery from low-permeability reservoirs. Zeinijahromi A et al 6 proposed a modeling method using a commercial reservoir simulator and used this modeling method to prove the relationship between low brine injection and enhanced oil recovery. A large number of experimental studies have been carried out on the mechanism of the waterflooding in low-permeability reservoirs mainly focusing on the study on the mechanism and the dynamic characteristics of oil-water percolation employing intuitive observation methods provided by advanced equipment of the nuclear magnetic resonance (NMR) technology in macroscopic experiments.…”

“…Constant-pressure parallel waterflooding experiment under different ranges Considering the influence of the heterogeneity, different ranges(2,4,6,8) were designed for the constant-pressure parallel flooding experiment. The viscosity of the crude oil used in this experiment was 5.6 mPa•s.…”

Reservoir formation damage during hydrate dissociation in sand-clay sediment from Qilian Mountain permafrost, China

“…Gas and water production at longer time scales may be hindered by formation damage caused by the low permeability of the hydrate reservoir and the fresh water release from hydrate decomposition. The fresh water release may cause clay swelling and clay detachment as well-known from enhanced oil recovery by low-salinity water flooding [24][25][26]. At a longer time-scale of production from a hydrate-bearing reservoir formation damage may become an important issue.…”

Fines Stabilization by Ca Ions and Its Effect on LSW Injection

“…5,43−46 In contrast with this enhancement of microscopic sweep efficiency, some simulation studies have demonstrated that by progressively damaging the fastest swept layers, fines migration can increase the reservoir scale sweep efficiency, thus unlocking additional reserves. 45 Due to the demonstrated effectiveness of fines migration in increasing both the microscopic and macroscopic sweep efficiencies, many low-salinity waterflooding projects aim to maximize particle detachment. Typically, this is achieved through minimization of the injected fluid salinity or by combining the low-salinity flood with alkaline solutions.…”

“…When low-salinity brine is injected into porous media, this equilibrium is disturbed and, as a result, clay particles are detached and mobilized by the drag forces caused by the displacing phase. ,,− Migration of fines leads to the aforementioned fines straining in the rock. As a result, water-permeable channels are plugged and the flow is directed toward unswept zones where residual oil is trapped. ,,− This microscale flux diversion causes a decline in water relative permeability and an increase in pressure drop, which improves microscopic sweep efficiency by mobility control, resulting in enhanced oil recovery. ,− …”