| 摘要 |
The invention relates to a method for preventing the sticking due to a pressure difference in the well of the drill string to the wall of a well during the rotary drilling of hydrocarbon wells. The flow point of the drilling fluid is measured and, if required, increased in a manner known per se to a minimum value calculated from the weight of the drilling fluid such that solid, essentially spherical glass particles with a relative density of between 2.4 and 2.65, a diameter of between 0.25 and 4.75 mm and a hardness of 5.5 Mohs in the fluid do not settle, 1200 to 6000 g per litre of glass balls being added to a specified quantity of drilling fluid. A slurry consisting of the mixture of glass balls and drilling fluid is then injected into the well in a predetermined region of possible sticking, with the result that a considerable number of the glass balls is deposited in the filter cake lining the well in the said region of possible sticking. The presence of the glass balls prevents the formation of a seal between a drill string, the drilling tool or housing and the filter cake. Such a seal gives rise to differential sticking to the wall. In an alternative procedure, the mixture of glass balls and drilling fluid is pumped into the well without regions of possible sticking ... Original abstract incomplete.
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