| 摘要 |
Process and arrangement for treating recirculated drilling mud during oil or gas drilling, in particular offshore and primarily when using oil-based drilling fluids, possibly water-based drilling fluids. The invention aims at the attainment of cleaned drill cuttings without environmental drawbacks and/or recovery of useful constituents of the drilling fluid. There is included a de-gasser step (3), a vibration screen unit (6) and one or more steps (10, 20, 30, 50) for separating coarse and finer drill cuttings respectively from the drilling mud. The invention in particular comprises the combination of: a) separation in a first step by employing a screw classifier (10) having a closed tube (13) surrounding the screw (12) and a supply (15) of oil, possibly water in counterflow against the conveying direction in the screw classifier as well as an overflow (17) for drilling mud from the screw classifier tank (11), (b) transfer of drilling mud from the overflow (17) to cyclone means (20) having an associated screen device (22) for separating drill cutting particles from the drilling mud, and c) de-watering in at least one vibration de-watering unit (30) to which there is supplied superheated vapour and chemicals preferably in the form of leaching solution and metasilicate, and which receives separated drill cuttings from the screw classifier (10). |
