預防卡鑽及提高排阻成功率之研究

鑽鑿深井時，常會發生卡鑽問題，發生卡鑽後，須要進行排阻或打撈工作。如果被卡鑽串於井內靜置太久，會造成其他原因之阻卡，使排阻之成功率降低，甚至於須放棄打撈。打撈工作會造成工程進度之落後及鑽井成本之重大損失。鑽井卡鑽發生之因素頗為複雜，故需預為探討分析並採取防制措施。本研究探討卡鑽三大機制、卡鑽發生之原因、徵兆及其預防、差壓粘卡分析、U形管降低差壓排阻法、浸泡Pipe-lax排阻法、並針對現場卡鑽及排阻事故分析及檢討。在鑽井過程中，鑽井工程人員若能瞭解卡鑽發生之可能原因，並加以防範，可避免很多卡鑽及打撈之發生。卡鑽發生原因可分為1.井內有固體導致卡鑽；2.機械及井況導致卡鑽；3.差壓黏卡導致卡鑽等三大機制。定向鑽井增角鑽進中為能鑽出平順之井程及避免發生卡鑽，若井程偏距與計劃偏距差異不大時，應避免修正井程，或俟鑽至適當地層再修正。鑽進中應參考泥漿測錄預估之地層壓力及實際井況，適時調整泥漿比重，以減少及避免差壓黏卡或崩井等問題。本研究成果將可應用在國內外油氣鑽探之鑽井工程，可避免意外事故發生、改善鑽井工程及降低鑽井成本。

關鍵字

卡鑽；匙孔；差壓黏卡

並列摘要

Drill pipe may get stuck in the borehole for several reasons: part of the borehole collapsing on to the drill pipe; high angle dogleg; or high borehole/formation pressure differential. The most common reason for the borehole collapsing on to the pipe is that the formation interstitial salt water forming a bond with the water in the drilling mud. This can cause the shale to expand and slough off into the borehole causing stuck pipe. The drill pipe can also get stuck in the borehole when borehole pressure is much higher than the formation pressure. The high pressure differential can build up thick mud cake that may cause stuck collars during tripping out. If the drill pipe gets stuck at a dogleg, it is probably because the drilling angle deviated slightly in the drilling process. When the drill stem is pulled from the hole, the drill pipe or the slightly larger drill collars get stuck at the dogleg. Since the borehole is seldom straight, the opportunity for dogleg stuck pipe is always present. This paper interpreted and applied stuck pipe prevention and free pipe technology. Results can be applied to drilling engineering to minimize stuck pipes and thereby the drilling costs.

並列關鍵字

Stuck pipe ； Key seat ； Differential sticking

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