低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。

Study on Starting Pressure Gradient for Low Permeability Heterogeneous Sandstone Reservoir

By combining theoretical derivation with experimental study, the method of determining starting pressure gradient for low permeability heterogeneous sandstone oil reservoir was established. Firstly, based on the similar principles of reservoir flow field and electric field, equation applied to calculating starting pressure gradient for heterogeneous sandstone reservoir was derived. Secondly, based on steady flow test technique, testing method applied to acquiring starting pressure gradient for heterogeneous sandstone reservoir was established. The results show that determining starting pressure gradient of low permeability heterogeneous sandstone reservoir follows the two equivalent principle. The starting pressure gradient for horizontal heterogeneous reservoir is equal to the weighted average of the starting pressure gradient on length. The starting pressure gradient for vertical heterogeneous reservoir is equal to the weighted average of the starting pressure gradient on the product of permeability and flowing area. The results can effectively guide the determination of reasonable well space and promote the efficient development for low permeability heterogeneous sandstone reservoir.