Patent ID: 12246411

It should be understood that the drawings and the associated descriptions below are intended to illustrate one or more embodiments of the present invention, and not to limit the scope or the number of different possible embodiments of the invention.

In the description of the invention which follows, unless specified otherwise, terms ‘upper’, ‘upward’ and ‘upwards’ are used to denote a direction upwards towards top of the well-bore or towards the source of fluid flowing through the tool. Similarly, terms ‘lower’, ‘downward’ and ‘downwards’ are used to denote a direction downwards towards the base of the well-bore or towards the direction of fluid flowing through the tool, which is left to right in all figures.

Some components and/or portions of the embodiments of the invention illustrated in the figures may not be fully discussed in the description which follows, because they are not needed to provide a full and complete description of the embodiments of the invention, which is adequate for comprehension by anyone with relevant experience in the field.

It should be noted that the drawings are not necessarily drawn to scale.

DETAILED DESCRIPTION

Reference will now be made in detail to a first embodiment of a fluid-driven dual-mode abrasive perforation tool of the invention with reference to the accompanying figures. An exploded view of the first embodiment of the fluid-driven dual-mode abrasive perforation tool100is shown inFIG.1. Tool100includes an upper sub102, a lower sub104, a barrel106, a tubular centralizer108, a J-slot piston110, a spring112, a retainer ring114, and a covering sleeve116. Other parts inFIG.1are discussed below.

When an assembled fluid-driven dual-mode abrasive perforation tool100is installed in a well-bore, an internally threaded upper end118of the upper sub102is fixed with the string or coiled tubing (or other equipment assembly in the well-bore) to receive fluid inflow. When the tool is in neutral operation mode, after entering tool100, the fluid exits through lower end120of lower sub104and gets delivered into the Bottom Hole Assembly (BHA), or other equipment assembly, connected to the externally threaded region of lower end120.

As illustrated, an externally threaded region122towards the lower end124of the upper sub102is screwed with an internally threaded upper end126of the barrel106. An externally threaded upper end128of the tubular centralizer108is screwed within the lower end124of the upper sub102. Covering sleeve116is housed within and towards the lower end176of barrel106. The outer surface of the covering sleeve116includes locking keys174which mate within slots182(not shown) on the internal surface of the barrel106, such that the covering sleeve116sits rotationally fixed within the barrel. The internally threaded lower end176of the barrel106is screwed with an externally threaded upper end130of the lower sub104. The covering sleeve116further includes multiple symmetrically distributed cylindrical guiding pins132(explicitly illustrated inFIGS.3A and3B) on its internal surface. The longitudinal axis of each of the guiding pins132is transverse to the axis of the covering sleeve116.

The lower sub104further includes a first pair of opposed flow paths154and a second pair of opposed flow paths156(see cross-sections ofFIGS.2A,2B,5A-5F,6A-6C and7A-7C). Each of the first pair of opposed flow paths154connect the upper end130of the lower sub104with the curved exterior of the lower sub104. Similarly, each of the second pair of opposed flow paths156respectively connect the upper end130of the lower sub104and with a central bore152of the lower sub104. Externally threaded nozzles158are screwed into internally threaded exits160of each of the first pair of opposed flow paths154. The expanded opening at the lower end120of central bore152does not extend through the lower sub104.

Within the lower sub104, each of the first pair of opposed flow paths154lie parallel to each other and are not interconnected. Similarly, each of the second pair of opposed flow paths156lie parallel to each other and are not interconnected. Also opposed flow paths154are not connected to the second pair of opposed flow paths156.

J-slot piston110is housed within barrel106and can slide between limits within it. The J-slot lot piston110further includes ratchet head134and a tubular shaft136. On the ratchet head134, a ratchet path138is formed by etching the outer curved surface of the ratchet head134to form multiple mating peaks162and valleys164. Multiple peak channels172are included between adjacent peaks162, and multiple valley crests178are included between adjacent valleys164. In an assembled tool100(as shown inFIGS.2A,2B,6A-6C, and7A-7C), the ratchet head134is housed within the covering sleeve116in a manner such that the guiding pins132are engaged within the ratchet path138. The tubular shaft136is a hollow tube including a central bore168. Within the ratchet head134, the J-slot piston110further includes a pair of flow channels166which extend axially through the ratchet head134(seeFIGS.1and4). Each of the flow channel166connect the central bore168with a lower end170of the ratchet head134.

The tubular shaft136slidably covers at least a partial length of a lower hollow shaft140of the tubular centralizer108. The ratchet head134is confined to slide between the upper end130of the lower sub104and an annular restriction142on the internal surface of the barrel106. Since the guiding pins132are engaged with the ratchet path138, sliding of the ratchet head134between the upper end130of the lower sub104and the annular restriction142causes its rotation. Irrespective of whether the ratchet head134slides from the upper end130of the lower sub104to the annular restriction142, or whether it slides from the annular restriction142to the upper end130of the lower sub104, the direction of rotation of the ratchet head134(and hence the J-slot piston110) always remains the same. Dimensions and mating of the peaks162, valleys164and peak channels172of the ratchet path138are chosen such that every complete downward slide of the ratchet head134, after its complete upward slide, causes its rotation by a prefixed angle such that, every time the lower end170of the ratchet head134strikes and pushes against the upper end130of the lower sub104, the flow channels166get alternately aligned with the first pair of opposed flow paths154and the second pair of opposed flow paths156. When the lower end170of the ratchet head134strikes and pushes against the upper end130of the lower sub104, and when the flow channels166get aligned with the first pair of opposed flow paths154, the entrances to the second pair of opposed flow paths156remains sealed. Similarly, When the lower end170of the ratchet head134strikes and pushes against the upper end130of the lower sub104, and when the flow channels166get aligned with the second pair of opposed flow paths156, the entrances to the first pair of opposed flow paths154remains sealed.

The tubular shaft136is further surrounded by the spring112and the retainer ring114is screwed on the externally threaded upper end144of the tubular shaft136(or of the J-slot piston110). The span of spring112is confined to be within the separation of annular restriction142and the retainer ring114.

In the assembled tool100, a central bore146of the upper sub102, a central bore148of the tubular centralizer108, the central bore168(shown inFIGS.6A-6C, and7A-7C) of the J-slot piston110and a central bore150of the barrel106are axially aligned (SeeFIGS.2A,2B,6A-6C, and7A-7C).

The operation of the assembled fluid-driven dual-mode abrasive perforation tool100, when deployed in a coiled tubing of a well-bore will now be explained with the help of accompanying figures.

FIGS.2A and6Aillustrate state of tool100in a state of rest with no fluid entering. In this state, the spring112is in expanded state and the ratchet head134lies adjacent to the annular restriction142. The entrances to first pair of opposed flow paths154and the second pair of opposed flow paths156are open.

To make perforations on a target site, tool100is placed into the wellbore in a manner such that the target site lies next to the fluid ejection nozzles158. Then, pressurized fluid is injected into upper sub102(from upper end118). From the upper sub102, pressurized fluid travels through the central bores146,148, and then through the pair of flow channels166(seeFIG.6A) to get delivered into the central bore150of the barrel106. Finally, the pressurized fluid travels through the first pair of opposed flow paths154and the second pair of opposed flow paths156, and gets ejected out of the tool100through nozzles158and through the lower end120of the lower sub104. At this stage, since all flow paths154and156are open, the magnitude of pressure of fluid jet ejecting through nozzles158is insufficient to cause perforations on the target site. However, downflow of pressurized fluid against the restrictions presented by flow channels166exerts a downward force on the J-slot piston110As a result, the J-slot piston110is pushed downwards.

As the J-slot piston110moves downwards under the pressure of the inflowing fluid, the spring112gets compressed, and the peaks162of the ratchet path138push against guiding pins132of sleeve116(SeeFIGS.6B-6C). Since the sleeve116(and pins132) are rotationally fixed within the barrel106, the edges of the peaks162slide against pins132causing the ratchet head134(and the entire J-slot piston110) to rotate until the pins132enter and fall into the peak channels172. Once pins132fall into peak channels172, the ratchet head134is freely pushed downwards such that the lower end170strikes against and pushes on the upper end130of the lower sub104(seeFIG.6B). Longitudinal downward displacement of the J-slot piston110also results in further compression of spring112. At this stage, the flow channels166of the ratchet head134get aligned with the first pair of opposed flow paths154(i.e. the entrances of the first pair of opposed flow paths154get aligned with the exits of the flow channels166), and the entrances of the second pair of opposed flow paths156get sealed by the lower end170of the ratchet head134(seeFIG.6C).

Since the second pair of opposed flow paths156get sealed, the pressurized fluid flowing through the tool100finally travels only through the first pair of opposed flow paths154and gets ejected in the form of high pressure fluid jets from nozzles158, for perforating a target site. At this stage, the tool100works in ‘abrasive’ mode. It is to be noted that injected pressurized fluid could be a stream of concentrated fluid containing suspended solid particles, like sand, directed against the target (for example, a casing wall) to cut through it. By adjusting the suspended particle size and fluid pressure a better control over depth and size of the perforations is achieved.

Next, when it is desired to switch off the ‘abrasive’ mode and to make the tool100operate in a ‘neutral’ mode, flow of pressurized fluid through the tool100is interrupted (or the fluid pressure is reduced below a threshold) in order to reduce downward compression force on the spring112. As the fluid pressure is reduced, the downward pressure on the J-slot piston110is reduced, and spring112expands and pushes the retainer ring114upwards.

As a result of upward force on the retainer ring114, the entire J-slot piston110(including the ratchet head134) is pulled upwards (SeeFIG.7A). This causes the valley crests178of the ratchet path138to hit and push against guiding pins132of sleeve116. Since the sleeve116(and pins132) are rotationally fixed within the barrel106, the edges of the valley crests178slide against pins132causing the ratchet head134(and the entire J-slot piston110) to rotate until the pins132fall into an adjacent valley164. This causes the ratchet head134to be pushed upwards such that its upper end180strikes against and pushes on the annular restriction142on the internal surface of the barrel106(seeFIG.7A). At this stage spring112achieves maximum expansion, and since the lower end170of ratchet head134moves away from the upper end130of the lower sub104, the entrances of the flow paths154and156are unsealed.

At this stage, reinstating the pressurized fluid flow causes the J-slot piston110to slide downwards under the pressure of the inflowing fluid. As the J-slot piston110slides downwards, spring112gets compressed, and the peaks162of the ratchet path138push against guiding pins132of sleeve116(SeeFIGS.7B-7C). Since the sleeve116(and pins132) are rotationally fixed within the barrel106, the edges of the peaks162slide against pins132causing the ratchet head134(and the entire J-slot piston110) to rotate until the pins132enter and fall into the peak channels172. Once pins132fall into peak channels172, the ratchet head134is pushed downwards such that the lower end170strikes against and pushes on the upper end130of the lower sub104. Complete longitudinal downward displacement the J-slot piston110also results in further compression of spring112. At this stage, the flow channels166of the ratchet head134get aligned with the second pair of opposed flow paths156(i.e. the entrances of the second pair of opposed flow paths156get aligned with the exits of the flow channels166), and the entrances of the first pair of opposed flow paths154get sealed by the lower end170of the ratchet head134(seeFIG.7C).

Since the first pair of opposed flow paths154get sealed, the pressurized fluid flowing through the tool100travels only through the second pair of opposed flow paths156, gets delivered into bore152and finally gets ejected out of the tool from lower end120of the lower sub104. The tool100is operating in ‘neutral’ mode.

Thereafter, again interrupting and reinstating the flow of pressurized fluid causes the J-slot piston110to again strike and push against the upper end130of the lower sub and causes the tool100to switch operation to the ‘abrasive’ mode as explained above.

It is noted that during longitudinal displacement of the J-slot piston110, the tubular shaft136(along with its upper end144) also gets displaced longitudinally by sliding over the lower hollow shaft140of the tubular centralizer108. The presence of lower hollow shaft140within the central bore168of the tubular shaft136minimizes longitudinal deviations of the J-slot piston110during its longitudinal displacement. Hence, guided longitudinal displacement of the J-slot piston110due to the lower hollow shaft140of the tubular centralizer108ensures smooth longitudinal displacements (with minimal deviations) of the J-slot piston110. This also results in smoother operation of tool100.

The specifications of the spring112in terms of the fluid pressure required to cause its compression and expansion during operation of the tool are fixed. So, the amount of fluid pressure which would overcome the force of spring112and push the J-slot piston110down, and the amount of fluid pressure which would not withstand the expansive force of compressed spring112are known to the operator of the tool. In other possible embodiments of the present invention, instead of a single pair of flow channels (as described above), the J-slot piston may include an additional pair of flow channels. During operation, every time when the J-slot piston pushes against the upper end of the lower sub, while the first pair of flow channels would always get aligned with either of the first pair or the second pair of flow paths, the second pair of flow channels would always get aligned with the other pair of flow paths. However, the exits of the additional pair of flow channels may be kept blocked by a sealing mechanism. In an embodiment of the invention, such a sealing mechanism could be implemented by screwing externally threaded cylindrical plugs (made of an elastomeric material) into internally threaded exits of each of the additional pair of flow channels. When aligned with either pair of flow paths, a protrusion of such plugs would also block the entrance of the flow path they would push against. Other mechanisms to seal and block the flow path, other than protrusions or plugs, could also be used and are within the scope of the invention.

It is to be understood that the foregoing description and embodiments are intended to merely illustrate and not limit the scope of the invention. Other embodiments, modifications, variations and equivalents of the invention are apparent to those skilled in the art and are also within the scope of the invention, which is only described and limited in the claims which follow, and not elsewhere.