考虑动态启动压力梯度的低渗底水油藏油井见水时间预测

Prediction of Water Breakthrough Time of Oil Wells in Low Permeability BottomWater Reservoirs Considering Dynamic Threshold Pressure Gradient

为解决预测油井见水时间因没有考虑变启动压力梯度和应力敏感效应导致结果与实际值相差较大的问题,基于非达西渗流理论,建立了考虑变启动压力梯度和应力敏感效应的油井见水时间预测模型,并分析各影响因素敏感性。结果表明:预测模型计算的见水时间与油藏实际见水时间基本吻合,相对误差仅6.99%。应力敏感效应和避水高度与见水时间呈正相关性;原油黏度、产液强度、启动压力梯度系数、压敏效应及垂向渗透率与水平渗透率的比值与见水时间呈负相关性。该模型对低渗透底水油藏见水时间预测具有很好的指导性。

At present,when predicting the water breakthrough time of oil wells in low permeability bottom water reservoirs,the influence of variable starting pressure gradient and stress sensitivity is not considered,resulting in a large difference between the predicted value and the actual value.Based on the non-Darcy seepage theory,a oil well water breakthrough time prediction model considering variable starting pressure gradient and stress sensitivity is established,and the sensitivity of various influencing factors is analyzed.The results show that the water breakthrough time calculated by the prediction model is basically consistent with the actual reservoir water breakthrough time,and the relative error is only 6.99%.There is a positive correlation between stress sensitivity effect,water avoidance height and water breakthrough time.Oil viscosity,production strength,starting pressure gradient coefficient,pressure sensitivity effect and the ratio of vertical permeability to horizontal permeability are negatively correlated with the water breakthrough time.This model has good guidance for the water breakthrough time prediction of the oil wells in low permeability bottom water reservoirs.