A productivity evaluation method based on movable water for offshore low permeability and high water content gas reservoirs
High primary water saturation of low permeability gas reservoirs in the Ledong area of the western South China Sea,exploration wells testing have a high water gas ratio and significant interlayer differences,the occurrence status and movable conditions of pore water are unclear,and the production capacity of water producing gas wells is not accurately understood.Through gas-water displacement and nuclear magnetic resonance experiments,the occurrence characteristics and variation patterns of movable water in cores with different permeability have been clarified,and a movable water saturation prediction model has been established.A productivity evaluation method based on movable water production has been proposed.The study shows that the pore throat radius of low permeability gas reservoirs is small,and movable water mainly exists in larger micron and submicron pore throat.There is an exponential positive correlation between movable water saturation and displacement pressure gradient,the main controlling factors for movable water saturation in type Ⅰ core is permeability,while the main controlling factor for type Ⅱ core are permeability and displacement pressure difference.The porosity of movable water is linearly positively correlated with the porosity of the core,and logarithmically positively correlated with the permeability of the core,the porosity of movable water in type Ⅰ core under the extreme displacement pressure difference is about 8％,while that in type Ⅱ core is significantly lower,ranging from 4.2％to 6.2％,and is greatly affected by the permeability.The production capacity evaluation method based on movable aquatic products has been applied effectively in exploration wells in Ledong area,which can reasonably guide the production capacity research of development wells in Ledong area.
low permeability gas reservoirhigh water saturationmovable waterdisplacement pressure differencegas water two-phase steady-state productivity
万方数据
维普
