Gas Injection Optimization under Uncertainty: Impact of Selective Well Completion and Reservoir Parameters on Dynamic Response and Economics in a Giant Gas Condensate Reservoir in Venezuela

2010 ◽  
Author(s):  
Angel Gonzalez ◽  
Guillermo Griborio
Keyword(s):  
Dynamic Response ◽  
Gas Injection ◽  
Gas Condensate ◽  
Optimization Under Uncertainty ◽  
Well Completion ◽  
Condensate Reservoir

Equilibrium Revaporization of Retrograde Condensate By Dry Gas Injection

1968 ◽  
Vol 8 (01) ◽  
pp. 87-94 ◽  
Author(s):  
Lowell R. Smith ◽  
Lyman Yarborough
Keyword(s):  
Gas Flow ◽  
Water Saturation ◽  
Gas Injection ◽  
Gas Condensate ◽  
Dew Point ◽  
Reservoir Pressure ◽  
Sweep Efficiency ◽  
Flowing Fluid ◽  
Condensate Reservoir ◽  
Gas Cycling

Abstract This paper presents results of a laboratory study of retrograde condensate recovery by revaporization into dry injection gas. Flow tests were performed in 10.6-ft long sandpacks at 100F and 1,500 psi. In three runs methane revaporized the liquid from a n-heptane-methane mixture in the presence of immobile water. Two of these tests were water-wet, and the third was totally oil-wet. In the three runs n-heptane recovery was complete after 2.5 hydrocarbon PV of injection. There was no significant performance difference between the two wettability extremes. In a fourth experiment, a methane-hydrogen sulfide mixture revaporized a synthetic light, sour condensate. No water saturation was present. Equilibrium compositions and volumetric data were obtained for the four-component condensate. The heavy component, n-heptane, was removed alter 6 PV production. Comparison of the effluent fluid compositions with known equilibrium data shows that the flowing fluid was equilibrium vapor and that the mixing zone between equilibrium vapor and dry injection gas was short. Data indicated that complete recovery of retrograde liquid occurred after it was contacted by a sufficient quantity of dry gas. Introduction When pressure declines below the fluid dew point in a gas condensate reservoir, a liquid phase forms. In this process, referred to as retrograde condensation, the quantity of liquid formed is frequently small enough that the liquid is not a flowing phase. To prevent loss of valuable retrograde liquids, the process of dry gas cycling has been employed for several years as a more or less standard practice. In this procedure the reservoir pressure is maintained above the fluid dew point so that the liquid components may be produced as vapor and then separated at the surface. Although full pressure maintenance by gas cycling seems ideal in terms of preventing liquids loss, several factors can reduce the attractiveness of such an operation. From a study of a condensate reservoir in Alberta, Canada, Havlena et al. concluded that cycling under conditions of declining pressure leads to economic advantages and to a high recovery of hydrocarbon liquids. This study considered effects of volumetric sweep efficiency, retrograde behavior of the original wet gas and revaporization characteristics of the retrograde liquid when contacted by dry gas. The first major work concerning revaporization of liquid in a gas condensate system is that of Standing et al. Calculations based upon the PVT behavior of a recombined gas condensate fluid indicated that all retrograde liquid can be recovered if it is contacted by a sufficient quantity of dry gas. The paper considered the effect of variable permeability upon the recovery of retrograde liquid. Standing et al. concluded that recovery of heavier components in the retrograde liquid is greatest if reservoir pressure is allowed to decline below the dew point prior to dry gas injection. Since the work of Standing et al., several laboratory studies have been reported which show that recovery of hydrocarbon liquids by vaporization into dry injected gas can contribute to increased recovery above that obtained by ordinary production practices. Vaporization from retrograde condensate, conventional oil and volatile oils reservoirs has been considered. There is little work that deals with revaporization recovery from condensate reservoirs. SPEJ P. 87ˆ

Gas Injection for Enhancement of Condensate Recovery in a Gas Condensate Reservoir

2015 ◽  
Vol 37 (8) ◽  
pp. 799-806 ◽  
Author(s):  
M. Nasiri Ghiri ◽  
H. R. Nasriani ◽  
M. Sinaei ◽  
S. H. Najibi ◽  
E. Nasriani ◽  
...  
Keyword(s):  
Gas Injection ◽  
Gas Condensate ◽  
Condensate Reservoir

scholarly journals An evaluation on phase behaviors of gas condensate reservoir in cyclic gas injection

2020 ◽  
Vol 75 ◽  
pp. 4
Author(s):  
Angang Zhang ◽  
Zifei Fan ◽  
Lun Zhao ◽  
Anzhu Xu
Keyword(s):  
Phase Behavior ◽  
Gas Injection ◽  
Gas Condensate ◽  
Reservoir Pressure ◽  
Retrograde Condensation ◽  
Condensate Reservoir ◽  
Gas Drive ◽  
Phase Behaviors ◽  
Equilibrium Calculations ◽  
Better Than

Maintaining the reservoir pressure by gas injection is frequently adopted in the development of gas condensate reservoir. The aim of this work is to investigate the phase behavior of condensate oil and remaining condensate gas in the formation under gas injection. The DZT gas condensate reservoir in East China is taken as an example. The multiple contact calculation based on cell-to-cell method and phase equilibrium calculations based on PR Equation of State (EOS) were utilized to evaluate the displacement mechanism and phase behavior change. The research results show that different pure gas has different miscible mechanism in the displacement of condensate oil: vaporizing gas drive for N2 and CH4; condensing gas drive for CO2 and C2H6. Meanwhile, there is a vaporing gas drive rather than a condensing gas drive for injecting produced gas. When the condensate oil is mixed with 0.44 mole fraction of produced gas, the phase behavior of the petroleum mixture reverses, and the condensate oil is converted to condensate gas. About the reinjection of produced gas, the enrichment ability of hydrocarbons is better than that of no-hydrocarbons. After injecting produced gas, retrograde condensation is more difficult to occur, and the remaining condensate gas develops toward dry gas.

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