石油钻探技术
石油鑽探技術
석유찬탐기술
PETROLEUM DRILLING TECHNIQUES
2015年
4期
113-117
,共5页
倪小明%胡海洋%曹运兴%庞东林%郭志企
倪小明%鬍海洋%曹運興%龐東林%郭誌企
예소명%호해양%조운흥%방동림%곽지기
煤层气%憋压阶段%排采%工作制度%放气套压
煤層氣%憋壓階段%排採%工作製度%放氣套壓
매층기%별압계단%배채%공작제도%방기투압
coalbed methane%pressure build up stage%drainage%production system%casing releasing pressure
煤层气井提产阶段和稳产阶段需要确定合理放气套压，才能够获得稳定的气流补给。根据煤储层启动压力梯度、渗流理论和煤层气开发地质理论，构建了煤层气井憋压阶段套压变化的数学模型；利用沁水盆地大宁区块的煤层气勘探开发资料验证了该模型的准确性，并分析了放气套压差值对平均日产气量的影响规律。模型计算结果与现场数据吻合较好时，煤层气井的产气量较高；当计算出的放气套压与实际放气套压的差值小于等于0.15 M Pa时，煤层气井稳产期的产气量能达到1000 m3／d以上；大于0.15 M Pa时，需要降低产气量来维持其稳定性。研究结果表明，日产气量随实际放气套压与计算值之间差值的增大呈幂函数减小，建立的煤层气井憋压阶段合理放气套压数学模型可为现场排采控制提供理论依据。
煤層氣井提產階段和穩產階段需要確定閤理放氣套壓，纔能夠穫得穩定的氣流補給。根據煤儲層啟動壓力梯度、滲流理論和煤層氣開髮地質理論，構建瞭煤層氣井憋壓階段套壓變化的數學模型；利用沁水盆地大寧區塊的煤層氣勘探開髮資料驗證瞭該模型的準確性，併分析瞭放氣套壓差值對平均日產氣量的影響規律。模型計算結果與現場數據吻閤較好時，煤層氣井的產氣量較高；噹計算齣的放氣套壓與實際放氣套壓的差值小于等于0.15 M Pa時，煤層氣井穩產期的產氣量能達到1000 m3／d以上；大于0.15 M Pa時，需要降低產氣量來維持其穩定性。研究結果錶明，日產氣量隨實際放氣套壓與計算值之間差值的增大呈冪函數減小，建立的煤層氣井憋壓階段閤理放氣套壓數學模型可為現場排採控製提供理論依據。
매층기정제산계단화은산계단수요학정합리방기투압，재능구획득은정적기류보급。근거매저층계동압력제도、삼류이론화매층기개발지질이론，구건료매층기정별압계단투압변화적수학모형；이용심수분지대저구괴적매층기감탐개발자료험증료해모형적준학성，병분석료방기투압차치대평균일산기량적영향규률。모형계산결과여현장수거문합교호시，매층기정적산기량교고；당계산출적방기투압여실제방기투압적차치소우등우0.15 M Pa시，매층기정은산기적산기량능체도1000 m3／d이상；대우0.15 M Pa시，수요강저산기량래유지기은정성。연구결과표명，일산기량수실제방기투압여계산치지간차치적증대정멱함수감소，건립적매층기정별압계단합리방기투압수학모형가위현장배채공제제공이론의거。
In the stage of stable production and production increase of coalbed methane wells ,it is nec-essary to determine the reasonable casing releasing pressure to obtain stable air supply . Based on the threshold pressure of coal reservoir ,seepage theory ,CBM development geology theory etc .,a mathematic model of releasing pressure for CBM wells was established .From CBM exploration and development data of Daning Block ,Qinshui Basin ,the accuracy of the mathematic model was verified .The relations between casing pressure drop and average daily gas production were analyzed .When predicted pressure from this model was in good agreement with that applied in field data ,gas production of CBM Wells would be high-er .When the pressure difference was within 0.15 MPa ,the average daily gas production of CBM wells could be more than 1 000 m3/d in stable production stage .When the pressure difference was more than 0.15 MPa ,daily gas production would be stabilized at lower gas production rate .The results showed that daily gas production is reduced in power function with casing pressure drop and the mathematical model of casing releasing pressure in coal bed methane well can provide theoretical basis for CBM wells production .
