长庆苏里格气田欠平衡钻井井壁稳定性预测研究

WELL-BORE STABILITY PREDICTION OF UNDER-BALANCED DRILLING FOR SULIGE GAS FIELD IN CHANGQING OIL FIELD

为了减少气层污染和加快苏里格气田的勘探速度 ,长庆油田综合应用欠平衡钻井技术和水平井技术进行钻探 ,随之带来了水平段的井壁稳定问题。文章利用摩尔 -库仑准则、Drucker -Prager准则和LADE准则对长庆油田苏里格气田苏平 1井的井壁稳定性进行了预测。结果表明 ,Lade准则具有更好的临界钻井液密度预测效果。同时 ,垂直主应力的不确定性是影响苏里格气田苏平 1井井壁稳定预测效果的最主要因素 ,6 0～ 6 5MPa是预测段垂直主应力的合适范围。

For the purpose of reducing pollution to gas reservoir and speeding exploration of Sulige Gas Field, both under-balanced and horizontal drilling techniques were used in Changqing Oil Field. So, the problem of well-bore stability happened for the horizontal section. The More―Coulomb criterion, Drucker―Prager criterion and Lade criterion were used to predict the well-bore stability of well Suping 1 in Sulige gas field. The results show that Lade criterion obtains the best prediction for the critical density of drilling fluids, and the uncertainty of the vertical stress is the most important factor that effects the prediction accuracy of the well-bore stability of well Suping 1. The proper range to predict the vertical stress is between 60 MPa and 65 Mpa.