钻井过程储层无机垢损害的时空尺度数值模拟及应用

Numerical Simulation and Application of Time-space Scale of Reservoir Inorganic Scale Damage during Drilling

钻井过程结无机垢现象普遍存在,由于缺乏对问题井的结无机垢损害程度、损害半径的有效判断,难以进行有效的储层保护,造成储层堵塞,完井后无法达到配产。针对于钻井过程中常见的碳酸钙、硫酸钙、硫酸钡、硫酸锶等类型无机垢损害,建立力学化学耦合的微分方程组数学模型,实现无机垢损害的时空尺度模拟,模型的准确性在渤海某油田得到验证和应用。基于此模型探索钻井压差、储层温度、储层压力等模型参数对结无机垢损害程度的影响,钻井过程中的储层无机垢损害应以预防为主,合理控制钻井压差是关键。

Inorganic scaling is a common phenomenon during drilling.Due to the lack of effective judgment on the damage degree and damage radius of inorganic scaling in problem wells,it is difficult to conduct effective reservoir protection,resulting in reservoir plugging and failure to achieve production allocation after well completion.Aiming at the common types of inorganic scale damage such as calcium carbonate,calcium sulfate,barium sulfate,strontium sulfate,etc.in the drilling process,a mathematical model of differential equations coupled with mechanics and chemistry was established to realize the time-space scale simulation of inorganic scale damage.The accuracy of the model has been verified and applied in an oilfield in Bohai Sea.Based on this model,the influence of model parameters such as drilling pressure difference,reservoir temperature,and reservoir pressure on the degree of inorganic scale damage was discussed.The prevention of inorganic scale damage in the reservoir during drilling should be given priority,and the reasonable control of drilling pressure difference is the key.