Operations/Maintenance

1. How do you control the velocity of the tool traveling up the well bore?

There are two ways to control the upward velocity of the tool:
    a) Restrict the well flow rate at the surface by choking the well back;
    b) Longer flow time4s between cycles that will build a higher hydrostatic column. The tool will lift more fluid in the         process.

2. How fast will the tool travel up the we llbore and still be efficient?

The maximum effective velocity for the tool travelling up the well bore ranges between 300-450 feet per minute, subject to the individual well conditions. Exceeding the optimal rate may cause some resonating and become counter productive.

3. How does the tool stop at the bottom of the well?

Incorporated into the design of the tool is a 3" polyurethane ball that serves a number of purposes. It acts as a valve creating a seal as the ball closes against the lower mandrel of the tool at the time that it makes contact with the surface of the casing stop. It also has the ability to absorb shock. The poly ball between the seating surfaces of the tool and the casing stop provides for an extremely good shock absorber. This is a key component as casing stop bumper springs are inherently problematic. The presence of fluids in the well bore between cycles also adds to the cushioning effect slowing the tool as it drops through the fluid approaching the stop.

4. How often do I have to service the tool?

Of course the first answer is "every well is different". However, preventative maintenance is easily monitored through gas flow chart readings, fluid rates, and travel times. If gas flow rates decrease or travel times increase, the tool can be checked in the surface lubricator between cycles.

5. What is the maintenance or replacement frequency of the seals?

In an oily gas well, seals will last up to 3000 cycles in a typical 500 ft (150 m) well. At 2 cycles per day, the seals can last up to 50 months.

In a dry gas well that produces water and formation grit, seals will wear more rapidly and last up to 1200 cycles in a shallow 2500 ft (800 m) well.

6. Can I service the well during break up?

Yes. Since the tool rests on the surface lubricator during cycles, easy access via a half ton truck is all that is required.

7. Can the tool get stuck or lodged in the casing? What procedures are used to correct or prevent the tool from getting stuck or lodged?

There are three reasons the tool might get stuck or lodged in the hole and all three reasons are ultimately caused by a failure to form a complete positive seal against the casing wall.

1. The first reason is sealing element failure due to wear and tear. This failure is usually gradual and can be prevented by monitoring the charts and tankage for a drop in production rates and/or increase in cycle time. A quick inspection of the sealing elements will confirm wear and tear. An element change can be performed at the next optimal recovery.

2. The second reason is sealing element failure due to blockage of the internal valve in the open position thereby jamming it preventing seal. This can be caused by frac sand, formation sediment, wax, asphaltines or a combination of these substances being allowed to collect unchecked over time. Again, the failure is usually gradual and diligent monitoring of the performance charts can identify the problem and prevent failure with tool maintenance. This can be corrected by manually "stop cocking", that is shutting in the well for a short period of time to build pressure then "stop cock". Often, allowing the well to flow will dislodge solids, close the internal valve and raise the tool to surface. If left unchecked, particularly with frac sands or loose formation sediment, the tool can become buried in sediment at the bottom of the hole, In this case, the tool can be fished from the bottom with a wire line or the sand can be blown out with ETU. Remember, this can only occur when the down hole stop is set below the upper set of perfs delivering the sediment.

It is important to remember that sealing element failure is preventable with monitoring practices. The reasons this tool is deployed are to optimize the production performance. Problems of fluid or sediment production and frac sand recovery are not eliminated; they are optimized along with gas and oil production.

3. The third reason is failure to cycle the pump due to inadequate gas inflow and reservoir pressure. This can be caused by unknown reservoir parameters prior to installing the tool. It is important to maximize the reservoir data input to the candidacy of a well in order to increase the probability of success.