| 摘要 |
A wellbore obstruction-clearing tool connected to the bottom of a tubing string, such as casing, utilizes a sleeve which is axially and rotationally moveable in response to axial reciprocation of a tubing string to engage and clear obstructions in the wellbore. Fluid is discharged through the casing and the tool to engage the obstructions and to convey debris through the annulus to surface. Thus, the obstructions are cleared from the wellbore, permitting the casing to be advanced, without the need to rotate the casing. |
| 主权项 |
1. A wellbore obstruction-clearing tool, fit to a downhole end of a tubing string for advancing the tubing string through obstructions in a wellbore, the tubing string having an axial bore therethrough for communicating fluids to an annulus between the tubing string and the wellbore for circulation to surface, the tool comprising:
an inner tubular mandrel for connection to the downhole end of the tubing string, the mandrel having a mandrel bore extending axially therethrough, the mandrel bore being fluidly connected to the axial bore; an outer tubular sleeve rotatable about the inner tubular mandrel and extendable therealong having,
a sleeve bore extending axially therethrough and fit concentrically fit about the mandrel, the sleeve bore being fluidly connected with the mandrel bore, anda downhole end for engaging the wellbore obstructions; and a helical drive arrangement acting between the mandrel and the sleeve for permitting reciprocating downhole and uphole axial movement of the inner tubular mandrel within the outer tubular sleeve to drive the outer tubular rotationally in the first direction about the mandrel towards a retracted position and driving the outer tubular sleeve rotationally in an opposite direction about the inner mandrel towards an extended position respectively, the engagement of the downhole end of the sleeve creating debris from the wellbore obstructions, and wherein the fluids from the sleeve bore convey debris along the annulus to surface. |
