非饱和油田白垩渗透特性的试验研究

利用改进的常水头压力渗透仪对非饱和油田白垩进行了试验研究,试验中采用轴平移技术来控制基质吸力,据以研究非饱和油田白垩的渗透特性及其影响因素.结果表明,油田白垩的渗透性与其所承受的应力、渗压梯度和基质吸力都有着密切的联系.随着围压的增大,白垩孔隙比和油渗透性都随之下降,表现出明显的压敏效应;渗压梯度的增大,在一定程度上降低了油渗透系数;注水作用使白垩内部含水量提高、基质吸力降低,并使油渗透性降低.上述研究成果为在石油开采工业中探索提高原油采收率的新技术提供依据.

An Experimental Study on Permeability of Unsaturated Petroleum Chalk

The oil permeability and its influence factors in unsaturated petroleum chalk were studied by carrying out some experiments with a specially improved constant head permeameter where the matrix suction was controlled with axis translation technique.The results show that the permeability is closely related with the confined stress, hydraulic pressure and matrix suction. With the developing of confined stress,the chalk presents an evident pressure sensitive effect that both the void ratio and oil permeability decreas. The oil permeability drops down with the increasing of hydraulic pressure, so that the water flooding in oil reservoir raises the water content in chalk, which will make the matrix suction and oil permeability decrease consequently. The results provide a reference for increasing the oil recovery in petroleum production.