Multi cycle Circulating bypass valve
I. Description.
The Multi-Cycle Circulating Bypass Valve has been designed to offer large circulating thru bores, along with large circulating ports The tool operates by utilizing an Indexing' mechanism. This provides a positive, Open or Close' position, each and every time the tool is functioned. The 'Drop 8all' cannot be 'ACCIOENTAUL' pumped thru the tool during the 'Cycle open' function.
II. Advantages.
1. The MCCBV is the perfect tool for use in 'High Angie' and 'Horizontal' wells as the tool functions as the ball passes thru the tool and does not relay on the ball reaching the catcher seat to function tool open.
2. All tools have two large circulating ports as standard which greatly reduces the risk of plugging.
3. The MCCBV is the only tool of its type that permits 'FULL TFA REVERSE CIRCULATION'.
4. Due to the unique design of the multi-cycle tools, the flow ports are open before the activating ball reaches the catcher seat. Thus preventing the ball inadvertently being sheared thru to the catcher basket.
5. The multi-cycle tool can be run into the well bore in the locked open' position
6. All tools permit a minimum of six open and close Unctions as standard. This number can be doubled on request.
III. Demensions.
Sub OD | 4.3/4’’ | 61/2’’ | 7.00’’ | 8.00’’ |
Connection | NC38 | NC50 | NC50 | 6-5/8 Reg |
Washpipe ID | 1.75’’ | 2.50’’ | 2.50’’ | 3.00’’ |
Circulating Port ID | 2x 1.125’’ | 2x 1.50’’ | 2x 1.50’’ | 2x1.50’’ |
Ball OD | 1.75’’ | 2.375’’ | 2.375’’ | 2.875’’ |
Number of cycles available | 6 Open/6 Close | 6 Open/6 Close | 6 Open/6 Close | 6 Open/6 Close |
Ball Shear Pressure | 1500-1800psi | 600-800psi | 600-800psi | 600-800psi |
Make-up Toque | 11,000ft/Ibs | 20,000ft/Ibs | 25,000ft/Ibs | 34,000ft/Ibs |
Shoulder to shoulder Length | 105’’ | 132’’ | 132’’ | 137’’ |
IV. Operating Procedures
OPENING SEQUENCE
1. Record circulating pressure at normal GPM rate.
2. Record circulating pressure at reduced rate i.e. 30SPM.
3. Release activating ball into drill string and pump to within 1000ft. of circulating sub, reduce pump rate to 30SPM
4..Continue pumping at reduced rate until a pressure increase of approx.600-800psi is observed. Continue pumping until a rapid drop in circulating pressure is observed.
indicating Flow ports are now in the locked open position Pumps can now be stopped if required.
5. Normal or reverse circulation can now take place with the activating ball isolating the drill string below the multi-cycle sub.
Example:
Circulating pressures to open too! thru bit (Reduced Circulating Rate +Ball Shear
Pressure)
30SPM ^ 600PSI + 800PSI - 1400PSI
New circulating pressure thru by-pass ports = 250PSI
Note: Above is an example only. Actual circulating pressures must be observed and recorded during opening sequence.
CLOSING SEQUENCE
1. Record circulating pressure at normal GPM thru by-pass ports.
2. Record circulating pressure at reduced rate i.e.30SPM
3. Release activating ball into drill string and pump to within 1000ft of circulating sub. reduce pump rate to 30SPM.
4. Continue pumping at reduced rate until a pressure increase of approx. 600-d00psi is observed. Continue pumping until normal circulating pressure thru drill string a( reduced rate is observed, indicating flow ports are now In the locked closed position and both bails have sheared thru to the basket catcher sub. Pumps can now be stopped if required. Or normal circulating thru the total drill string continued.
Example:
Circulating pressures to close tool (Reduced Circulating Rate Bail Shear Pressure)
30SPM * 250PSI + 800PSI * 1050PSI
New circulating pressure thru total string * 600PSI
Note: Above is an example only. Actual circulating pressures must be observed and recorded during dosing sequence.
V. Ball Retrieval
To recover activating balls:
1. 8reak tools joint between circulating sub and catcher sub.
2. Pull catcher basket from ball catcher sub.
3. Remove ball seat snap ring from hanger
A.Knock out ball seat and recover balls.
5. Clean out ball seat recess.
6. Re-install ball seat and snap ring.
7. Re-install catcher basket in catcher sub.
8. Remake tool joint to correct torque.
VI. Maintenance
1. The MCCBV must be maintained after working every time.
2. The seals and thread pins must be changed in each maintained process.
3. The cam grooves of sliding sleeve must be checked when maintenance required. If it has a large abrasion to influence the cam working, you should change a new sliding sleeve.
4. In maintenance, the sliding position of sleeve and cam groove should be smeared
lubricating grease.
5. Do not re-use balls.