试油工程中防止油气层污染的压井技术探讨

WELL KILLING TECItNIQUE IN OIL PRODUCTION TEST TO PREVENT THE POLLUTION OF HYDROCARBON RESERVOIRS

压井是试油中经常采用的一项工艺技术。多年来对于压井暂闭通常是采用重泥浆压井,有时还在井内加注一个水泥塞。对于压井酸化,通常是在井底压降较大的情况下进行。过去的这种压井方法不仅对地层造成了较严重的污染,而且有些井还造成了严重的工程事故,耗费了大量的人力和财力。为了防止这些问题的发生,着重针对四川碳酸盐地层高压高产气井的压井暂闭、常规压井酸化增产措施中防止地层污染、防止工程事故的问题进行了研究。从实际应用出发,总结出一套现场实用施工方法和施工工艺参数的近似计算公式。通过现场实践证明,采用高回压法压井能够达到暂闭和减少污染,防止工程事故。

For many years ,heavy mud and cement plug are used in well killing for temporary well shut-in, well killing acidize is often done when the bottom hole pressure drop is great. This way of well killing will not only pollute the reservoir;but also cause serious accidents, based on the research and practice of well king in high pressure,high-yield gas wells of carbonate formations formation pollution control in conventional well killing acidize;and the prevention of engineering accidents,a field practical operating method and the approximate calculation formula for the operating parameters are obtained. Applying in field practice proves the problems can be solved by the using of high back pressure in well killing.