低渗透油藏含水与可采储量采出程度关系

RELATION BETWEEN WATER CUT AND RECOVERY PERCENT OF RECOVERABLE RESERVES IN LOW-PERMEABILITY RESERVOIRS

以大庆外围35个低渗透油藏的开发数据为基础，利用丁型水驱曲线分析得到了不同区块水驱曲线的截距a、斜率b和可采储量NR，并由此推导建立了外围低渗透油田含水率与可采储量采出程度关系公式，绘制了低渗透开发的含水变化的理论曲线。绘制的理论曲线形态为一条凹S型曲线，说明低渗透油田含水上升具有初期含水上升慢，后期加快的特点。另外，通过关系公式测算，近50％的可采储量在含水率达到20％之前采出，证明低含水阶段是低渗透油田开发的主要阶段。

Based on the development data from35 low-permeability reservoirs in Daqing peripheral oilfields, the intercept a, slope b and recoverable reserves Ns of water flooding curves for different blocks are obtained by using the T-shaped water flooding curve, therefore the relational expression between water cut and recovery percent of recoverable reserves of low-permeability reservoirs in Daqing peripheral oilfields is derived and established, and the theoretical curve for water cut variation in low-permeability reservoir development is drawn. The shape of the theoretical curve is a concave S-shaped curve, which indicates that the water cut increases slowly in the early period of oilfield development, and rapidly in the later period. Additionally, after measured and calculated by the relational expres- sion, nearly 50% of the recoverable reserves could be recovered before the water cut reaches 20%, so it is proved that the low water cut stage is the major stage of the low-permeability reservoir development.