• 作者： 翁豐源
• 作者服務機構： 中國石油股份有限公司臺灣油礦探勘總處
• 中文摘要： 近年來我國工商業突飛猛進，隨著能源需要量劇增，政府為減輕對國外能源的依賴，正積極開發國內各種能源，其中地熱及深部源氣能源是為今後應加強探勘開發的主要目標之一。在地熱及深部油氣鑽探工程上必然遭遇之高溫將帶給工程上許許多多之困擾，尤其是用於下套管封固管外之水泥乳，因受高溫之影饗縮短初凝時間，劇烈降低硬化後之水泥耐壓強度、增加滲透性，惹起地層間之連通等等而造成鑽井工程之失敗或完井後不能獲得預期之熱汽或油氣生產而告廢棄。 鑒於此，本研究宗旨在配合臺灣地熱及深部油氣層探勘開發工程之需要，研討純水泥乳受高溫後之各種性質變化，耐壓強度脆化之原因及防止對策，並利用省產水泥、添加劑等研究配製耐高溫用套管水泥乳以及釐訂區域性套水泥乳之設計範式等，俾供工程設計施工上之依據，以確保工程之安全而達到開發高溫地下能源之目的。 經研究結果發現純水泥乳經250°F以上之高溫期齡結果所形成之矽酸＝鈣α水化物為造成水泥硬化後滲透性增加及耐壓強度脆化之原因。若水泥中添加對水泥重量百分比30～35％之省產矽砂粉或60～70％之省產飛灰，則水泥水化後形成新的Tobermorite水化物，此水化物在高溫下具有高耐壓強度，低滲透性之優點，是適合於地熱井及深部油氣井耐高溫水泥之用，並經實際應用於臺灣北部地熱井及各地區深部油氣井等之套管水泥工程上，收到防止高溫下生產層間之連通效果，且獲得預期之能源生產。本研究成果期能於能源危機聲中，對國家經濟發展有所貢獻。
• 英文摘要： In this paper, the Changes in the propertiesof neat cements upon the addition of nativefine-ground silica or fly ash are discussed. Datawere collected from formulations cured forperiods up to 3 days at high temperaturesvarying from 200° to 350°F. Compressivestrengths, permeabilities, porosities and thickeningtimes are compared. It is demonstrated thataddition of native silica or fly ash in properproportion results in a hydrated cement withsuperior properties above 250°F; i.e., earlycompressive strengths are higher and increasewith additional curing, permeabilities are signi-ficantly lower and thickening times are slightlydecreased. X-ray diffraction analysis of the hydratedcement samples have been used to determinemore fully the complex chemistry of these sy-stems. Dicalcium silicate alpha-hydrate wasfound in all neat cements which cured above250°F. A 10% silica or 20% fly ash additionproduced a maximum amount of this phase.Tobermorite has been identified as hydrationproducts at 280°F in systems containing 30-35%silica or 60-70% fly ash. Formation of thesecomponent appears to be primarily responsiblefor the gain in compressive strength and redu-ction of permeability observed after the additionof silica or fly ash. Based on this laboratory study, it is concluedthat formulation for silica-cement and fly ash-cement mixture are excellent for both high-temperature oil wells and thermal wells. Theseformulation have recently been successfullyemployed in deep oil wells and thermal wellsdrilling operation.
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