鄂尔多斯盆地长7油层组有效储层物性下限的确定

Determine Lower Limits of Physical Properties of Effective Reservoirs in Chang 7 Oil Formation in Ordos Basin

鄂尔多斯盆地长7油层组在湖盆中心大面积连续分布,孔隙度主要分布在4％～ 12％,渗透率一般小于0.3mD,属于典型的致密砂岩储层.而划分致密油含油边界关键技术之一是确定有效储层的物性下限.在测井解释、试油数据、储层物性分析等地质资料的基础上,根据统计学原理和超低渗透油藏流体渗流机理,分别采用经验统计法、物性试油法、孔隙度一渗透率交会法、油气驱替模拟实验法以及最小流动孔喉半径法5种方法,对该区有效储层物性下限展开研究.经过研究和综合对比,确定了长7油层组有效储层物性下限值为孔隙度5.7％、渗透率0.0276mD.

Chang 7 oil formation in Ordos Basin is distributed in the center of lake basin in a large area. The porosity ranges mainly from 4 percent to 12 percent while the permeability is less than 0.3roD. It is a typical tight sandstone reservoir. Determination of the lower limits of effective reservoir is one key technologies to divide the oil-bearing boundary of tight rock. Based on the geological data, such as logging interpretation, oil testing data and analysis of physical properties of reservoirs and in accordance with the statistical principles and super-low permeable oil reservoir fluid filtration mechanism, five methods are adopted to the lower limits of physical properties of the effective reservoirs in this block, such as experience statistical method, physical oil testing method, porosity-permeability intersection method, oil and gas displacement simulation method and minimum flowing pore throat radius method. The lower limit of physical properties of effective reservoir in Chang 7 oil formation is detemfined on the basis of the research and comparison. The porosity and permeability are 5.7 percent and 0.0276mD.