注汽速度对蒸汽驱全系统热损失的影响

为探讨高速蒸汽驱开采效果优于低速蒸汽驱的原因，将地面、井筒和地层当作一个系统来考虑，首先计算了不同注汽速度下的地面热损失，并以得到的井口参数为基础计算了不同注汽速度下采用光油管或隔热油管注汽时的井筒热损失；然后计算了不同注汽速度下不同厚度油层的地层热损失，从而得到了蒸汽驱全系统热损失与注汽速度关系曲线。结果表明，注汽速度是影响蒸汽驱全系统热损失大小的主要原因：注汽速度小于４８ｍ＾３／ｄ，蒸汽驱全系

Effects of Steam Injection Rate on the Whole System Heat Losses in Steamflooding

o investigate the causes of production performance of high rate steamflooding superior to that of low rate steam flooding,surface line,wellbore and formation are treated as the whole system.The heat losses of surface line at different steam injection rates are calculated first, then wellbore heat losses with tubing only and with insulated tubing at different steam injection rates are calculated on the basis of wellhead parameters obtained above. Formation heat losses for various thicknesses at different steam injection rates are calculated.The curves of total heat losses of the whole steamflooding system versus steam injection rates are obtained.Results of this study show that steam injection rates effect significantly on the total heat losses of whole steamflooding system.The whole system heat loss of low rate steamdrive (48 m3/d) may be over 70% (73.8%), while the heat loss of high rate steamdrive (360 m3/d) is only about 35% (35.6%). Moreover,well bottom steam quality of low rate steamdrive is very low. It also shows that oil pay thickness is not a main factor of effecting heat loss, thin heavy oil resvevior can be developed by high rate steamdrive.