Comprehensive Experimental Study on Fluid Phase Behavior and Reservoir Microstructure of Ultra-Deep Condensate Gas Reservoirs in Block A
DOI: https://doi.org/10.62517/jsse.202608204
Author(s)
Xiao Ge, Jufang Ge, Hongmei Wang
Affiliation(s)
Karamay Dayue Huashuo Petroleum Technology Co., Ltd., Karamay, Xinjiang, China
Abstract
The efficient development of ultra-deep condensate gas reservoirs in the Block A Block is hindered by two major factors: the complex fluid phase behavior under high-temperature and high-pressure (HTHP) conditions and strong reservoir heterogeneity, hence the necessity for a systematic experimental study. Therefore, the authors integrated three well-suited laboratory techniques: high-pressure PVT phase analysis, constant-rate mercury injection(CRMI),and oil-water relative permeability measurements, and applied them to fluid samples and corresponding core plugs from three representative wells(Block A 83,Block A 21,and Block A 6).The PVT results conclusively established that all three fluids are typical condensate gases with clearly distinguishable critical parameters, most notably critical condensate pressure ranging from 41.60MPa to 55MPa.The study examined the fluid phase behavior and phase envelopes, thereby clearly identifying the varying risks of retrograde condensation. CRMI analysis was used to systematically quantify the microscopic pore-throat structures, from which the dominant throat radius range controlling fluid flow was determined. Oil-water relative permeability curves were then employed to obtain reliable endpoints: irreducible water saturation and residual oil saturation, both crucial for assessing water displacement efficiency. Most importantly, the paper rigorously links fluid phase behavior and microscopic reservoir architecture to macroscopic flow capacity, thus providing solid experimental basis and direct practical guidance for optimizing development strategies in the Block A Block, especially regarding pressure maintenance and well placement.
Keywords
Block A Block; Condensate Gas Reservoir; Phase Behavior Analysis; Constant-Rate Mercury Injection; Relative Permeability; High-Temperature and High-Pressure (HTHP)
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