| 摘要 |
A downhole apparatus 10, such as a centraliser, stabiliser, cleaning tool, casing reamer shoe or motor sleeve comprises a tubular main body 12, a flow channel 14b extending at least part way along a length of the body and a flow guide 16b located adjacent an end of the channel. At least one dimension of the channel is non-uniform, and preferably the channel narrows towards its ends. The flow guide may be generally triangular with a vertex adjacent a restriction 32 at an end of the flow channel. In another aspect, the apparatus includes elongate ribs 20a, 20b upstanding from its outer surface 24 defining flow channels there between. Alternatively, the apparatus may comprise a tubing shoe, a sleeve or a cleaning tool having a non-uniform flow channel where an axis of the channel is disposed parallel to the length of the main body. |
