Observer By-Pass Sub

Observer By-Pass Sub is designed to be run in a clean-up string where it is desirable to open up communication between the ID of the drill pipe and the annulus when POOH.

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Description

Observer By-Pass Sub is designed to be run in a clean-up string where it is desirable to open up communication between the ID of the drill pipe and the annulus when POOH.
It is normally run above the Well Observer to provide an additional means of equalising pressure and fluid flow around the tool should it become full of debris when POOH. When run with the Well Observer it is run as a contingency device and is only opened if required. Unlike conventional single ball drop subs, the Observer By-Pass Sub allows fluid in the drill pipe above the tool to drain past the ball when the ports are open.
Other applications for the tool include being run as a drill pipe drain sub and being run in conjunction with a Single Action By-Pass Sub (SABS) to provide an additional circulation path down hole after the Single Action By-Pass Sub has been closed.

Two Ball Circulating Tool

1 Single Action by-Pass Sub4 1/2 "

2 Single Action by-Pass Sub 7"

3 Single Action by-Pass Sub 9 5/8"

4 Single Action by-Pass Sub>13 5/8"
Dual Action By-Pass Sub (DABS) is designed to be run in a drill string where it is desirable to jet the riser and wellhead/BOP area when running in the hole and/or when pulling out. The tool consists of a one-piece body with two sets of ports and two internal Ball Seats that can be moved to close and open the ports.

Other applications for the tool include; being run as a by-pass tool above a drilling motor and being run above small diameter pipe to allow it to self-fill or drain efficiently.

The tool is also available in a choice of two large ODs for applications where it is desirable to have the jetting ports close to the ID of the item being jetted.

Operation

The tool is run in the open position to jet and clean going through the Riser and wellhead/BOP area.   In this position, the tool will also self-fill whilst running in the hole.   The lower ports on the tool are then closed by dropping a ball and applying pressure to    shear the Seat. All fluid flow is then directed down through the tool and the other well clean-up operations can be carried out.

When pulling out of the hole, the upper ports can be opened by dropping a second ball and applying pressure. The Riser and wellhead/BOP area can then be re-jetted and cleaned. In this position the fluid in the string above the DABS can also drain down through the tool.
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Boost annular velocity for more complete cleaning
The SINGLE-ACTION BYPASS SUB circulating valve is used to remove drill cuttings, mudcake, and other debris that drilling deposits on the riser, blowout preventer (BOP), and wellhead walls. The valve completely removes these contaminants to ensure clean and effective cementing and completions operations.

Features
One-piece, full-strength mandrel
Balls retained on seats in tool
Design to boost annular velocity
Availability with 11- or 16-in- [279- or 406-mm-] OD sleeve
Sixteen 0.437-in [11-mm] jet nozzles at 22° phasing
Advantages
The large 11- or 16-in-OD sleeves enable the jets to clean closer to the profile
Where it is necessary to reopen and close ports after the initial cycle, two units can be run in tandem

If the DABS is run in conjunction with, and above,any pieces of debris that are dislodged but not circulated out during the cleaning of the wellhead/BOP   area will be collected in the FLASH Well Patroller as it is pulled out of the hole.

To protect the tool Body or Inner sleeve from erosion or washing, it is necessary to carry out   a pressure test at surface prior to re-running a DABS, please refer to Table 1. This is   especially important in drilling applications.