“下吐上漏”复杂井的堵漏压井实践

LOSS CIRCULATION CONTROL AND WELL KILLING IN A TROUBLOUS HOLE WITH“BLOWOUT BELLOW AND LOST CIRCULATION ABOVE

在多压力系统的长段裸眼内，钻遇高压油气水层时，往往出现“下吐上漏”等复杂情况，甚至出现卡钻事故。其处理难点在于，若先堵漏，堵漏液易被高压地层流体冲走；若先压井，又会发生井漏。一些井由于处理方法不当，虽投入大量人力、物力、财力仍出现井眼报废，造成巨大损失。满西２井在处理卡钻事故的套铣作业中，遇到“下吐上漏”的复杂难题。经对井下情况分析后，提出处理复杂情况的合理的堵漏液配方和浓度；堵漏液走前，压井液走后；施工中合理控制回压；允许少量漏，不允许有增量。采取堵漏压井同时进行的方法，成功地解除了该井的复杂问题，为处理类似复杂情况的井提供了实例。

While the high pressure oil , gas and water bearing formations are drilled within a large section of bare hole with multiple pressure systems, some troubles as 'Blowout below and Lost circulation above' always appear and even drill pipe sticking accident happens. Some difficulties in disposing such circumstances are: if the loss circulation control operation is made first, the sealing fluid will be easy to be washed away by the high pressure formation fluid; if,however, the well killing operation is made first; the lost circulation will happen. Owing to the unsuited disposal methods, some wellshad to be scrapped although a lot of manpower, material and financial resources were put into thus causing a tremendous loss. The complex circumstances of 'Blowout below and Lost circulation above' were met in the casing milling operation for disposing the drill pipe sticking accident in well Manxi 2. Through analyzing the downhole conditions, the following works were finished, i.e. choosing the reasonable formulation and concentration of sealing fluid for disposing such complicated circumstances; pumping the sealing fluid into the borehole first, then the well killing fluid; reasonably controlling back pressure in operation; and promising a few fluid to be lost without any increment. By means of such a method which the loss circulation control and well killing were simultaneously carried out, the complex problem occuring to the well was successfully solved, which provided an example for disposing the wells with the same complicated circumstanced.