塔河油田奥陶系灰岩漏层钻井技术

Drilling Technology of Ordovician Limestone Leakage Zone in Tahe Oil Field

塔河油气田目的层是古生界奥陶系地层，其油藏类型比较特殊，一般埋藏在5500米以下，是一种以灰岩岩溶为起因，以缝洞系统储集体掩藏的复杂油藏。在钻井施工中，由于地层溶洞裂缝比较发育，地层孔隙连通性好．地层对钻井液密度很敏感，安全窗口小，地层的平衡点难以掌握和控制，常常井漏与溢流并存。根据该油田的地层特点，有针对性地制定相应的钻井技术，减少处理井漏、溢流情况的时间，达到了缩短钻井周期，提高生产经济效益的目的。本文详细介绍了塔河油田奥陶系灰岩各种漏层对钻井的危害及相应的钻进技术，通过现场4口井的施工表明，该技术成功地实现了奥陶系灰岩漏层的钻进，解决了钻进过程中井漏与溢流并存，即开泵井漏并置换出油气、停泵外溢的技术难题。

The target layer of Tahe oil ＆ gas field is Palaeozoic Ordovician layer and oil reservoir of which is very special with burying depth usually under 5500m. Originated from limestone karst, the reservoir is complicated with fractured cave reservior bodies hidden inside. In the drilling operation, because of the relatively developed formation cave fractures, well connected formation pores and high formation sensitivity to drilling fluild, it is difficult to control formation balance and lost circulation and well kicks often exists simutaneouly. Refering to the formation features of the oil field, relative drilling measures shall be taken to reduce the time to tackle with lost circulation and well kicks and furthermore reduce the drilling circle and increase the economic benefits. This article introduces the various drilling risks caused by Ordovician limestone thief zones In Tahe Oil Fileld and relative drilling technologies in detail. Proved by on-field drilling operation of 4 wells, the technologies make the drilling in Ordovician limestone leakage zones possible and solve the problems of coexistence of lost circulation and kicks in drilling.