砂岩油田合理注水压力的确定

Establishment of reasonable water injection pressure of sandstone reservoir

为防止砂岩油田超压注水时引起套管损坏 ,通过实验 ,分析了岩石破裂的影响因素 ,得出了油层破裂的压力计算公式 ,并根据射孔顶界油层特征和注水压力损失状况 ,确定了合理注水压力公式 .研究结果表明 :油层破裂压力与油层本身物性条件及围压大小有关 ;注水井合理的注水压力受其射孔顶界油层埋深、物性及构造特征的影响 ;注水过程中水嘴的压力损失及油管的沿程压力损失与单位时间内的注入量、水嘴直径大小和射孔顶深有关 .

To avoid casing damage caused by super pressure water injection of sandstone reservoir, the formation fracture pressure calculating formula is presented in the paper based on the analysis of the influencing factors for the rock fracture; and the reasonable water injection pressure is established from the perforating head oil formation characteristics and the losses condition of water injection pressure. The study shows the fracture pressure of oil formation is related to its own physical features and confined pressure conditions; the reasonable injection pressure is influenced by formation depth, physical features and structural features; the pressure loss of water nozzle and oil pipes are related to the injection rate unit time, the diameter of water nozzle and the perforated head depth.