济阳坳陷陆相油藏束缚油的计算方法

The Calculation Method and Cause of Irreducible Oil of Continental Reservoir in Jiyang Depression

砂岩油藏储层中不仅含有束缚水而且含有束缚油,有时束缚油的数值还较大,尤其在低孔隙度、低渗透率、高压油藏中;核磁共振、压汞实验等方法仅能得到储层的微孔隙体积百分含量,这些数值与束缚水饱和度有本质的差异;束缚油可分为原生束缚油和后生束缚油,油气的成藏动力与储层的成藏阻力的差异越大,越可能形成原生束缚油;沉积压实作用可形成后生束缚油。束缚油饱和度由微孔隙体积百分含量减去束缚水饱和度而得到,微孔隙百分含量可由核磁共振实验或压汞实验数据得到,束缚水含量由油基泥浆、密闭取心或测井解释得到。

There are both irreducible water and irreducible oil in sandstone reservoir, and some- times the amount of irreducible oil is great especially in such low porosity, low permeability and high pressure reservoirs. Volume percentage of micropore can be obtained from nuclear magnetic resonance and pressured-mercury testing, but these numbers have essential differences with irre ducible water saturation. Irreducible oil can be classified as original irreducible oil and epigenetic irreducible oil. Original irreducible oil is more likely to be formed in case of big difference be- tween reservoir-forming dynamic and reservoir-forming resistance. Epigenetic irreducible oil can be formed by sedimentary compaction. Irreducible oil saturation can be obtained from subtracting irreducible water saturation from volume percentage of micropore which can be got by nuclear magnetic resonance and pressured-mercury testing, and irreducible water content can be got by oil-based mud, sealed coring or log interpretation.