Perspectives and Composition of Oil and Gas Content of Mesozoic-Neozoic Complex in Condition of Usturt Region(Republic of Uzbekistan)

Constant increase of energy consumption leads to depletion of main energy resources,at first place oil and gas.This leads to the necessity of new research for mineral and raw material sources of energy,which is by itself very problematic.It requires involvement in development of new fields for oil and gas.On the other hand,the present stage of study of oil and gas in some territories shows that the possibility of exposure of hydrocarbon deposits in already known oil and

Velocity-porosity relationships in hydrate-bearing sediments measured from pressure cores,Shenhu Area,South China Sea

Evaluating velocity-porosity relationships of hydrate-bearing marine sediments is essential for characterizing natural gas hydrates below seafloor as either a potential energy resource or geohazards risks.Four sites had cored using pressure and non-pressure methods during the gas hydrates drilling project(GMGS4)expedition at Shenhu Area,north slope of the South China Sea.Sediments were cored above,below,and through the gas-hydrate-bearing zone guided with logging-while-drilling analysis results.Gamma density and P-wave velocity were measured in each pressure core before subsampling.Methane hydrates volumes in total 62 samples were calculated from the moles of excess methane collected during depressurization experiments.The concentration of methane hydrates ranged from 0.3%to 32.3%.The concentrations of pore fluid(25.44%to 68.82%)and sediments(23.63%to 54.28%)were calculated from the gamma density.The regression models of P-wave velocity were derived and compared with a global empirical equation derived from shallow,unconsolidated sediments data.The results were close to the global trend when the fluid concentration is larger than the critical porosity.It is concluded that the dominant factor of P-wave velocity in hydrate-bearing marine sediments is the presence of the hydrate.Methane hydrates can reduce the fluid concentration by discharging the pore fluid and occupying the original pore space of sediments after its formation.

Evaluation of gas condensate reservoir behavior using velocity dependent relative permeability during the numerical well test analysis

Gas condensate is one of the most different fluids in reservoir simulation due to retrograde condensation in case of pressure reduction.In this kind of fluids,two phenomena named negative inertia and positive coupling,become significant in the high velocity zone around the wellbore.In this study,a modified black oil simulator is developed that take into account the velocity dependent relative permeability.Against the industrial simulator that assumes linear variation of transmissibilities by pressure,modified black oil nonlinear equations are solved directly without linearization.The developed code is validated by ECLIPSE simulator.The behavior of two real gas condensate fluids,a lean and a rich one,are compared with each other.For each fluid,simulations of PVT experiments are carried out to calculate black oil property applying Coats approach for gas condensate fluids.For both fluids,the proposed models for gas condensate velocity dependent relative permeability show different influence of velocity on relative permeability in the same conditions.Moreover,it is observed that higher flow rate of gas production leads to more condensate production during constant rate well testing.

一种新的油气上窜速度计算方法——分段判定累计泵冲法

油气上窜速度是现场录井的重要参数之一,随着深井和超深井的开发,传统的迟到时间法和容积法已经不能满足现实的需要。因此提出了一种计算油气上窜速度的方法——分段判定累计泵冲法。分段判定累计泵冲法可以有效解决深井在起下钻过程中分段循环时油气上窜速度的准确计算问题。经过在实际中的应用论证,该方法可以在青海油田区块进行推广使用。