基于H-B强度准则的出砂风险预测方法研究与应用

Research and Application of Sand Production Risk Prediction Method Based on H-B Strength Criterion

随着海上弱胶结砂岩油藏的开发,储层压力衰竭以及含水等因素使得油井出砂风险随开采年限的增加而增大,因此出砂预测的精确性在油井完井方式的选择中显得尤为重要。文章引用了三维Hoek-Brown准则,考虑了储层压力衰竭对地应力的影响,通过室内清水浸泡实验得出岩石泡水后岩石强度的变化规律,总结出了一套适用于海上油田弱胶结砂岩储层的全生命周期出砂风险预测方法,并结合油田实例,绘制了弱胶结砂岩储层在整个油井生产周期中受地层压力衰竭和含水率上升影响的出砂临界生产压差版图。该出砂预测方法应用于南海文昌油田疏松砂岩储层时,预测结果与现场出砂情况吻合程度较高,根据该方法所绘制临界生产压差图版能够为油田确定合适的防砂时机、合理的防砂方式、适时调整生产压差提供理论依据。

With the development of offshore weakly consolidated sandstone reservoirs,pressure depletion,water cut,etc.,can increase the risk of sand production as the years go by,so the accuracy of sand production prediction is particularly important during the selection of well completion methods.In this paper,three-dimensional Hoek-Brown criterion is introduced,the influence of reservoir pressure depletion on in-situ stress is considered,and the change rule of rock strength after rock immersion is obtained through indoor water immersion experiment.A set of sand production risk prediction method suitable for weakly consolidated sandstone reservoirs in offshore oil fields is summarized.Combined with oilfield examples,the critical production pressure difference map of weakly consolidated sandstone reservoir due to pressure depletion and increasement of water cut during the whole production cycle of oil well is mapped.When the sand production prediction method is applied to the unconsolidated sandstone reservoir in Wenchang oilfield of South China Sea,the prediction results are in good agreement with the field sand production.The critical production pressure difference chart drawn by this method can provide a theoretical basis for determining the appropriate sand control time and reasonable sand control method and timely adjusting the production pressure difference.