南堡2-82井深层潜山充气欠平衡钻井试验

Aerated Underbalance Drilling Test in Deep Buried-hills of Well Nanpu2-82

南堡2-82井是冀东油田第一口潜山注氮气精细控压欠平衡井,井深4960m,设计垂深4200m,井底最大水平位移2412m,井底温度170℃左右。该井钻探的主要目的层是奥陶系潜山储层,施工中存在井深、井底位移大,潜山地层温度高,易漏失,钻井液安全密度窗口窄等难点。为解决潜山钻井难题,保护储层,及时发现油气,对井身结构进行了优化设计,使用抗高温钻井液,优选水基充氮气欠平衡钻井方式。在设计过程中利用欠平衡多相流软件对注气参数进行优化,并跟踪分析,实时调整充气参数。应用"欠平衡随钻监测与储层评价系统"对地层压力进行监测和评价,测量分析地层压力系数为1.027,与实测压力系数吻合较好。完钻后对奥陶系裸眼井段4876.21～4960.0m进行测试,折日产油122.4t/d,日产气32×104m3/d。与邻井相比,油气显示良好。

Well Nanpu 2-82 is the first one drilled under managed pressure and underbalance by nitrogen injection in the buried hill of Jidong oilfield,with 4960m of well depth ,4200m of designed vertical depth, 2412m of the maximum horizontal migration and about 170℃ at the bottom.The main intended interval of this well is Ordovieian buried hill reservoir,featured as deep well depth,large migration at the bottom,being easy to blow out and leak and narrow pressure window at high formation temperature when operation.In order to solve the drilling difficulties and prevent formations ,well structure is optimized and gasified liquid UBD is recommended to be used in this region.The gas injection parameters are optimized by the software of under- balanced multiphase flow,analyzed and adjusted in time.The system of monitoring while underbalanced drilling and reservoir evaluation is applied to monitor and evaluate the formation pressure.The measured formation pressure coefficient is 1.027,which matches well with the actual value.When drilling finished,open hole sec- tion from 4876.21 to 4960.0m is tested achieving 122.4t/d of daily oil production and 32×10^4m3/d of daily gas production.It has better show of oil and gas than the neighboring well.