FrequentlyAsked Questions
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The tensile strength averages 120,000-125,000P.S.I. and the yield strengthaverages 90,000-100,000 P.S.I. The working pressure averages 8,400 P.S.I., burstpressure averages 25,000 P.S.I. and the calculated collapse pressure averages23,500 P.S.I. The 1/4" O.D. x .035" wall tubing weighs 81.2 pounds per1000 feet and holds 5.29 quarts of liquid per 1000 feet. The 3/8" O.D. x.049" wall tubing weights 172.2 pounds per 1,000 feet and holds 12.52quarts of liquid per 1,000 feet.
| What preparations or modifications need to be done to a well to assure a successful installation? |
Typically, there are no modifications made to the wellhead other than the placement of a swage, flow tee and pack-off assembly used to control well pressure as we inject the tubing into the well.
Preparations should include testing of well bore fluids and chemicals for compatibility and temperature stability. A gauge ring should be run to the intended set point of the capillary tubing to assure at least a one-inch opening to the set point.
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The typical bottom hole assembly consists of a " inline check value, " NPT pipe coupling, and a perforated " pipe nipple, usually six inches long with the bottom end closed to prevent plugging as the system is run into the well. The maximum O.D. of the assembly is .75" O.D. and it is made from stainless steel. The assembly can be modified for special well conditions such as deviated holes, small diameters, etc.
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DIS does not supply any chemicals. However DIS has experienced successful applications with many chemical companies. We will be pleased to discuss these successes with you.
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DIS does not supply the chemical pump. We have had reliable service from several models and
types of chemical pumps, including solar powered pumps. We will be happy to tell you about these successes.
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No, we have not had the tubing part while hanging in a well. On a few occasions, the master valve has been closed and the tubing was cut and dropped.
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The DIS Chemical Injection System installation includes a suction line filter in the system to assure a clean, sediment free solution going downhole via the capillary string. Any fluids being injected through the capillary string must go through this filter to minimize the chances of plugging by foreign objects or materials. This filter should be checked and cleaned every 7 to 10 days to insure efficient operation.
On a few occasions the tubing has been plugged. The common problem has been chemical incompatibility and/or temperature instability.
| How is the tubing suspended/landed in the well head pack-off assembly? |
For the majority of wells, we use a hydraulically energized pack-off assembly that has a working pressure of 5000 P.S.I. The pack-off assembly has several safety features incorporated into it. When the pack-off assembly is set in a closed position there is a needle valve that is closed to maintain pressure on the pack-off and provide a positive seal on the tubing.
Once the tubing is in place, slips are installed on the tubing and set in the slip bowl of the packoff.
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cheap hotel in NurnbergThe tubing can be run to a depth calculated to be 23,500. This allows a 25% safety factor for the yield strength of the tubing.
| How many wells have you ran the tubing in, and how deep have you ran them? |
We have installed over 1500 systems. The deepest system we have installed is at about 22,000 feet.
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We have seen no indications that tubing movement in higher velocity gas wells has caused additional stress on the coiled tubing. The hole configuration will keep the tubing lying to the low side of the hole and helps prevent any movement of the tubing.
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Yes, we will gladly provide references upon request.
