Method and a device for cleaning an area located inside a restriction

A method and a device for cleaning an area (48) located inside a restriction (46) by means of a mechanical cleaning tool (1). The restriction (46) having a smaller cross-sectional dimension than the area (48) to be cleaned. The method includes the steps of moving the cleaning tool (1) into or through the restriction (46); moving a mechanical cleaning body (18) radially out into abutment against the area (48) to be cleaned; rotating the cleaning body (18) relative to the area (48) to be cleaned; moving the mechanical cleaning body (18) radially in from the area (48) which has been cleaned; and moving the cleaning tool (1) out from the restriction (46).

CROSS-REFERENCE TO RELATED APPLICATIONS

This United States National Phase of PCT Application No. PCT/NO2011/000298 filed 21 Oct. 2011, claims priority to Norwegian Patent Application No. 20101542 filed 3 Nov. 2010, each of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

This invention relates to a cleaning tool. More particularly, it relates to a method of cleaning an area located inside a restriction by means of a mechanical cleaning tool, the restriction having a smaller cross-sectional dimension than the area to be cleaned. The invention also includes a device for practising the method.

When, for example, components in a petroleum well are being cleaned, it happens relatively often that the area to be cleaned is inside a restriction which has a smaller diameter than the cleaning area.

An example is a downhole safety valve which needs to be cleaned of deposits, and wherein it is necessary to pass through a smaller opening to get in to the sealing area of the valve. It may also be relevant to clean portions of a pipe where the portion is inside a restriction, and where a plug is to be set, for example.

According to the prior art, brushes with relatively long, soft brushing elements are often used, which may result in uncertain effect of the cleaning operation.

The invention has for its object to remedy or reduce at least one of the drawbacks of the prior art.

The object is achieved in accordance with the invention through the features which are specified in the description below and in the claims that follow.

A method of cleaning an area located inside a restriction by means of a mechanical cleaning tool is provided, the restriction having a smaller cross-sectional dimension than the area to be cleaned, the method comprising:moving the cleaning tool into or through the restriction;moving a mechanical cleaning body radially out into abutment against the area to be cleaned;rotating the cleaning body relative to the area to be cleaned;moving the mechanical cleaning body radially in from the area which has been cleaned; andmoving the cleaning tool out from the restriction.

The method thereby makes it possible also for areas located inside a restriction to be cleaned mechanically in a satisfactory manner.

The method may further include activation of the cleaning tool by means of a rotary adapter which includes an actuator for the axial displacement of a pushrod, the rotary adapter being connected to a wireline tractor.

The cleaning tool is thus adapted to known equipment available at many points of application.

The method may be practised by means of a cleaning tool which includes a tool housing and a mechanical cleaning body arranged to clean the area in question by means of mechanical contact and relative movement between the cleaning body and an area to be cleaned, and which is characterized by the cleaning body being arranged on an attachment in which at least the part of the attachment holding the cleaning body is radially movable between a retracted, idle position and an extended, active position.

The distance between the centre axis of the cleaning tool and the cleaning body, when the cleaning body is in its extended, active position, is larger than half the cross-sectional dimension of a restriction located upstream of the area to be cleaned.

A pushrod may be connected to a cone which abuts against a corresponding first inclined plane internally on the attachment, an axial displacement of the cone in the direction of the free end portion of the housing bringing the attachment with the cleaning body to be moved radially outwards.

A compression spring which may be connected between the cone and the tool housing may be arranged to move the cone to its initial position.

The attachment may be formed with an external second inclined plane which is arranged to abut against an internal third inclined plane in the tool housing, an axial displacement of the attachment in the direction of the leading end portion of the tool housing bringing about an inward radial displacement of the cleaning body.

A guide ring which may be mounted on the rear portion of the tool housing may have been given a cross-sectional dimension that is larger than, for example, the cross-sectional dimension of the restriction.

Thereby the guide ring may be landed on, for example, a particular shoulder to positively position the cleaning tool in a particular position relative to the shoulder.

The tool housing may be connected to a rotary adapter which is provided with an actuator, and the actuator may be connected to the pushrod.

The rotary adapter may be connected to a wireline tractor.

The method and the device according to the invention make it possible for areas that are inside a restriction to be cleaned relatively easily by means of a mechanical cleaning tool.

In the drawings, the reference numeral1indicates a cleaning tool which is connected to a rotary adapter2and inserted into a pipe4in the ground.

The cleaning tool1includes a tool housing6which is connected to the rotary axle8of the rotary adapter2and which has been given a rounded conical shape at its opposite leading end portion10.

The tool housing6is formed with four longitudinal cut-outs12, there being, arranged in each of the cut-outs12, an attachment16for a respective cleaning body18, here in the form of relatively stiff-bristled brushes.

A pushrod20, stopping against an actuator22in the rotary adapter2, extends in part within a bore24in the tool housing6, seeFIG. 2. The pushrod20is connected to a cone26which abuts against a first inclined plane28on the inside of the attachments16. A compression spring30is arranged between the cone26on the opposite side relative to the pushrod20and the tool housing6near the leading end portion10.

Each of the attachments16is formed with an elongated resilient portion32which is attached to the tool housing6by means of a rupture body34. In its opposite end portion, the attachment16is provided with an external second inclined plane36which is arranged to cooperate with an internal third inclined plane38in the tool housing6.

The cleaning bodies18are attached to the attachment16by means of a clamp40and clamping bolt42.

A guide ring44has been slipped over the tool housing6and the resilient portion32at the rupture bodies34.

The cleaning tool1with the rotary adapter2is moved into a pipe4in which there is a restriction46, here in the form of a narrowing of the pipe4.

InFIG. 2, the cleaning tool1has partly been moved through the restriction46, the cleaning bodies18being at an area48which is to be cleaned.

When energy is supplied to the rotary adapter2, the rotary axle8and the cleaning tool1are rotated about their longitudinal axis50while, at the same time, the actuator22moves the pushrod20and cone26in the direction of the leading end portion10.

The displacement of the cone26has the effect of tightening the compression spring30while, at the same time, the cone26is being moved along the first inclined planes28, whereby, the attachments16with their respective cleaning bodies18are moved radially from an idle position into an active position, seeFIG. 3.

The bearing force and rotation against the area48to be cleaned has the effect of a reliable cleaning operation being performed.

When the cleaning operation has been carried out, the rotary adapter2is stopped. The compression spring30moves the cone26towards its initial position, whereby the resilient portion32turns the respective cleaning bodies18into their passive positions.

If one or more of the attachments16with cleaning bodies18should have got stuck in its/their active position(s), the rupture body34may be ruptured by moving the tool housing6in the direction of the rotary adapter2. The second inclined planes36of the attachments16are thereby moved against the third inclined planes38in the tool housing6. This has the effect of enabling the attachments16and the cleaning bodies18to be pushed radially inwards at relatively great force. The guide ring44prevents the attachments16from falling out of the tool housing6, seeFIG. 4.