水平井注采井网合理井距及注入量优化

Flood pattern optimization of horizontal well injection

为解决水平井注采井网中合理井距及注入量优化问题,利用渗流力学理论,考虑低渗、薄层油藏渗流特点,并假设注水井为刚性水驱,推导出考虑和不考虑水平井水平段压力损失两种情况下水平井注采井网的合理井距、合理注入量公式。根据公式分析认为,水平井水平段压力损失受管径、注水量或产油量、水平段长度影响。对于特定水平井,压降损失主要受产油量或注水量影响;对于确定的油藏,影响最大井距的主要因素是水平井长度、生产井产量、水井注水量。利用该研究结果设计的塔里木油田哈得4薄砂层油藏水平井注采井网在开发中起到了降低注入压力、增大注入量、有效保持地层压力的作用,应用效果良好。

To optimize well spacing and injection rate in horizontal well flood pattern, formulae of the reasonable injection rate and well spacing are derived under fraction and no-fraction conditions respectively using filtration theory. The formulae take into account the fluid flow in low-permeability and thin reservoirs, and assume that horizontal well injection is rigid water driving. According to these formulae, the influencing factors of pressure loss on the horizontal section are diameter of casing pipe, production rate, and length of horizontal section. For a well with fixed casing diameter and horizontal section length, the influencing factors of pressure loss on horizontal section is only production or injection rate; for a reservoir, the influencing factors of maximal well space are length of horizontal section, oil production rate and water injection rate. The research results are applied in the Hade 4 thin layer sandstone reservoir of Tarim Oilfield. The designed flood pattern decreases injection pressure, augments injection, and keeps field pressure.