异常高压超深凝析气井生产动态异常分析及对策

我国有丰富的深层天然气资源,深层气藏普遍存在高温和异常高压的特点,在试井、生产及井下作业方面都存在很大难度,且国内可借鉴的经验很少。柯深101井从开始试井投产起出现了一系列异常生产状况。以其为例,对异常高压超深气井的生产状况进行综合分析,认为应力敏感造成的近井地带应力损伤、凝析液造成的渗透率损害以及井筒积液、井内落物是造成生产异常的主要原因。针对以上原因提出了相应对策在进行产能试井及制定生产工作制度时,应综合考虑应力敏感及反凝析因素,压差不能过大;采用重复酸化或酸压措施改善近井地带的地层渗透率;当井筒积液严重后可采用气举方式排液,应用电磁加热技术减轻近井积液对产能的影响;井内掉入落物后应及时打捞,以免造成重大经济损失。

A Case Study: Reason Analysis and Measures of Abnormal Production of Ultra- deep Gas Well KS101 in Tarim Basin

Deep gas reservoirs generally have the characteristics of high temperature and abnormal high pressure, and there are many difficulties in well testing, gas production and downhole operation. However, the practical experience that can be referenced is very little in China. Gas well KS101 is an important ex ploration well located Kecaya condensate gas field in Tarim basin, during the producing of condensate gas and oil, series abnormal conditions occurred, which leaded to great fluctuation of production, and finally well KS101 could not produce normally. The main reason for abnormal production of well KS101 is permeability damage that is caused by stress sensitivity and condensate fluid. Another important reason is borehole junk, and a simple model is built up to explain the effect of borehole junk on production. For deep gas well with HTHP, it is suggested: the factors of stress sensitivity and retrograde condensation should be taken into account before well performance is determined, and the pressure differential should not be too large; near wellbore permeability can be improved by reacidizing or reacidizing fracturing; when liquid accumulation in wellbore is serious, gas lift and electromagnetic induction heating technology can be used to discharge down-hole liquid and improve near wellbore permeability. Moreover, borehole junk should be removed in time to avoid serious accident and loss.