蒸气吞吐井产能预测方法

PREDICTION OF DELIVERABILITY OF HUFF AND PUFF WELL

目前研究蒸气吞吐的解析模型主要有前缘驱替模型和重力超覆模型两类。文章根据蒸气吞吐井的生产特征,建立了两区复合油藏拟稳态数学模型;根据注入地层的热量为热损失与地层吸收的热量之和,计算出加热半径;注蒸气导致原油粘度下降是热力开采的重要机理之一。很多非牛顿流体的流变行为可以由幂律关系表征,文章用负幂指数形式来处理粘度在热区径向的变化,推导出一个新的考虑表皮系数产能公式。利用Marx-Langehei m计算加热区半径,对公式中的参数取值作了说明,并进行了实例研究。

There are mainly two types of huff and puff analytical models at present, one is frontal displacement model and another is gravity overriding model. Based on production performance of huff and puff well, a pseudosteady state mathematical model of two-block composite oil reservoir is built. Heating radius is calculated assuming that the amount of heat injected into formation equals to the sum of heat loss and heat absorbed. Lowering crude oil viscosity by injecting steam is one of the main mechanisms of thermal recovery. Rheological behavior of many non-Newtonian fluids can be described by using power-law equation, thus radial change of oil viscosity in hot-zone is treated in negative power exponential form to establish a new deliverability formula with skin effect being considered. Marx-Langeheim is used to calculate radius of hot-zone and selection of parameter values in the formula is explained. Case study shows that it can guide field prediction of deliverability of heavy oil well and provide a good basis for numerical simulation.