TITLE:
Application of Fluid Phase Recovery Method in the Early Development of BZ26-6 Volatile Oil Field in Bohai Sea
AUTHORS:
Zhennan Gao, Lei Zhang, Haojun Wu, Lei Huang, Xiaolong Gong
KEYWORDS:
Volatile Oil Field, Phase Fitting, Fluid Recovery, Gas-Oil Interface, Productivity Evaluation
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.11 No.9,
September
26,
2023
ABSTRACT: BZ26-6 Oilfield is a kind of deep metamorphic rock buried-hill volatile
oilfield in Bohai
Sea, China. Its early development plan is restricted due to the simultaneous production of oil and gas in large
sections of reservoirs, unclear understanding
of formation fluid properties and uncertainty of gas-oil interface. Through theoretical research on phase recovery and experimental analysis
of crude oil phase characteristics in the
original formation, characteristic parameters
of the equilibrium condensate gas fluid are restored and calculated. Through the superimposed phase
diagram of volatile oil and condensate gas, BZ26-6 Oilfield is determined to be
a volatile oil reservoir with a condensate gas
cap, with formation pressure and saturation pressure of 36.1 MPa, respectively. Based on the research results of oil-gas phase behavior
characteristics, the thermodynamic equations and equation of state are jointly
used to solve the problem, and the content
change curves of each component at different depths are drawn. Combined with the sensitivity analysis of numerical simulation, the gas-oil interface is determined to be -3726 m above sea level.
The fluid phase
analysis software, Fluidmodeler, is used to simulate volatile oil degassing and condensate gas separation experiments. In combination with oil
and gas production data obtained through the production test, the specific oil
recovery index and the specific gas recovery index are determined to be 0.408 m3/(MPa·d·m) and 1195 m3/(MPa·d·m),
respectively. And the reasonable production capacity prediction is conducted on the
early development of BZ26-6 Oilfield.
The research results can provide a theoretical basis for the efficient development of similar complex oil and gas reservoirs.