含裂缝低渗透油藏井网调整平面波及效率研究

合理部署注水开发井网以及研究低渗透油藏的水驱油渗流规律是经济有效地开发低渗透油藏的前提条件。通过对物理模拟结果的灰度处理,对比正方形反九点井网和菱形反九点井网的平面波及效率,优选出适用于含裂缝低渗透油藏开发的基础井网。通过对比正方形反九点井网与菱形反九点井网,发现:含裂缝低渗透砂岩油藏中,菱形反九点面积井网能有效扩大平行于裂缝方向的注采井距,缩小垂直于裂缝方向的注采井距,可有效改善平面上各油井的均匀受效程度,延缓角井水淹时间。开发后期,角井含水较高,基础井网不能满足开发需要时须适时进行加密转注调整。通过对比三种加密调整方式的面积波及系数,优选出适合含裂缝低渗透油藏的加密调整方案,有效指导含裂缝低渗透油藏的开发。

Study on the Areal Sweep Effectiveness of Well Pattern Adjustment in Low-permeability Reservoirs with Fractures

Reasonable arrangement of well patterns and the seepage law of water-oil displacement are the prerequisites for developing low-permeability reservoir effectively. The areal sweep effectiveness of square inverted nine-spot pattern and rhombus inverted nine-spot pattern were studied by plane visualization models and gray-scale processing in this paper. Based on the analysis and comparison of these well patterns, the best basic well pattern applied to fractured low-permeability reservoir was selected. By comparing square inverted nine-spot pattern and rhombus inverted nine-spot pattern, we found out that the effect of oil well was even and the water-out time was postponed when well spacing which paralleled to the direction of fracture was increased and when the well spacing which was perpendicular to the direction of fracture was shortened. In the later stage of production, the high water cut corner wells of basic well pattern were forced to be converted in order to keep the production of oil field and enhance the efficiency of oil wells. With the comparison of areal sweep effectiveness of three different well patterns, the best well pattern fitting for low-permeability reservoirs was given. This could help to effectively guide the development of low permeability reservoirs with fractures.