| 摘要 |
Sealing of an erupting shaft comprises injecting a dense, stable treatment fluid via a lateral shaft to form a temporary floating plug, and sealing the shaft by cementing the zone between the bottom of the shaft and the top of the treatment fluid. The treatment fluid is a suspension of three particle sizes in a liquid, in proportions chosen to maximize compaction, with a density of at least 4.5g/cm<3>. A suspension is injected via the lateral shaft or a second lateral shaft below the first, to fill the zone between the bottom of the shaft and the treatment fluid. Sporadic injections of fluid during stifling maintain the equilibrium of the shaft. The cementation uses a cement slurry suitable for repairs, or containing a micro-cement. The liquid:solid ratio of the treatment fluid is between 28:72 and 40:60. The fluid 28 to 40% (by volume) of an aqueous or oil base containing an agent dispersed in the base and other additives in solution; 72 to 60% heavy solid particles, in particular metal oxides with a density of at least 4 and preferably at least 4.5, divided into 66% particles of size 700 micro m, 25% particles of size 40-50 micro m and 9% particles of size 5 micro m. The solid particle are obtained by the crushing of hematite, magnetite Fe3 O4, hausmannite, pyrolusite, manganosie or ilmenite.
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