|
Abstract To deeply research the stress sensitivity of low permeability reservoir，the strong stress sensibility of low permeability reservoir is theoretically proved based on the capillary bundle model with varying diameters. The effects of effective stress，pore structure，stress loading mode on permeability are studied by laboratory experiments with varying fluid pressures，while keeping confining pressure steady. The effects of stress sensitivity on oilfield development under different formation conditions are studied by numerical simulation. The results show that：The effect of stress variation on porosity is very small，but its influence on permeability is very large. Comparing with high permeability reservoir，stress sensitivity of low permeability reservoir is stronger. Stress sensitivity is closely relative to effective stress，pore structure and stress loading mode. The stress sensitivity increases as the permeability decreases，the effective stress and the stress loading velocity increase. There exists permanent damage on permeability while the effective stress reduces，and the permeability cannot recover to the initial value. The producing pressure drop of the production well has a good exponential relationship with stress sensitive coefficient. The stronger the reservoir′s heterogeneity is and the lower the average permeability is，the larger the stress sensitivity is，and thus its effect on oil production is larger. However，the effect of rhythmicity on stress sensitivity is small. These results have guidance to develop low permeability reservoir reasonably.
|
|
Received: 10 May 2010
|
|
|
|
2011, Vol. 30 
