Evans Engineering, Inc.
LockJar FAQs

• What can the Evans LockJar do for me?

• What does the Enhancer do?

• What benefit does the hydraulic time delay provide?

• What is the standard duration of the hydraulic time delay?

• What makes the Evans Jar and Enhancer product more reliable?

• What kind of maintenance do the tools require?

• What are the initial costs of switching to LockJar products?

What can the Evans LockJar do for me?

The Evans wireline jar is the cutting edge of logging technology. Evans offers a variety of jars that can be used to save rig time and fishing costs in both open and cased hole operations. The cost of the jar activation is inconsequential when measured against the costs of rig time and fishing costs.

• As of February 2004 the Multi Conductor LockJar, in it’s first 14 months, (only using the Gulf Of Mexico) was run 41 times and was activated on 14 runs. At an average cost of $300,000 for a fishing job, the savings to customers could be estimated at over 4.2 million. On all of these jobs, the reliability of the multi conductor tool has been close to 100%, and there has been zero lost time during these jobs because of the jars.

• On one job in the Gulf of Mexico, the jar was activated over 20 times at six different intervals; and the well was successfully logged. This well was the first well in the field that was successfully logged without a fishing job.

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What does the Enhancer Do?

The basic job of the enhancer is to enhance the effectiveness of the Jar. The enhancer allows the customer to get more power behind the stroke of the jar while simultaneously taking stress off of the wireline. The enhancer stores the tension created when the line is pulled tight so that the potential energy is stored in the enhancer instead of the stretch of the wireline. The enhancer makes for a sustained and much greater impact when the jar is released. It also acts as a shock absorber for the wireline by absorbing the snap of the wireline after the jar has been activated and the tool string has been freed.

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What benefit does the hydraulic time delay provide?

The hydraulic time delay gives the operator more versatility while trying to free a stuck tool string. With a mechanical jar, the release values are preset and once the tension reaches that setting the jars are activated. With the hydraulic time delay on the Evans Jars, the operator can pull as hard as they deem necessary within the time delay. The harder the operator pulls the greater the impact when the jar releases. This allows the operator to pull harder if the original activation did not free the tool string, or to pull at his maximum on the first activation, if the hole conditions require.

The hydraulic time delay also allows customers the freedom to try to free their tool string by pulling through a tight space. With a mechanical jar, the jars are activated once the tension reaches their release value, even if activation is not necessary to free the tool string. With the time delay, a customer can pull on the tool string using the logging truck for short periods without causing the jars to activate. This is a benefit that our competitors do not allow.  Hydraulic time delay saves customers money on unnecessary activations and saves stress on the tools in the tool string.

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What is the standard duration of the hydraulic time delay?

The time delay varies depending on how high the lock setting is set and how much over pull the operator employs when trying to free the tool string. The time delay will be between 30 seconds and 1 minute and thirty seconds depending on how much the operator pulls over the lock setting. If the lock setting is set at 2000 lbs and the operator pulls at 6000 lbs the jar will release after 30 seconds. If the lock setting is at 2000 and the operator pulls at 2500 lbs the jar will release after 1 minute 30 seconds. This allows customers to vary the force used to jar on the tool string depending on the situation.

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What makes the Evans Jars more reliable?

The design of the Evans Jars makes them both more reliable and more user friendly. Unlike mechanical jars, the Evans Jars are pressure balanced and sealed off from the well bore. This keeps the working parts of the jar and the conductive path protected from the hole environment and makes it possible to run the Evans Jars on several jobs without the need for rebuilds after every run like the mechanical jars. This saves time at the rig because the jars don’t have to be serviced after each run and because the conductive path has a much lower chance of failure because it is not exposed to the hole environment.

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What kind of maintenance do the tools require?

Evans Jars do not need to be serviced after every run the way that mechanical jars do. They can be used on several runs and through several activations without the need for redress. Because the tools are hydraulic, their working parts are not exposed to the well bore which significantly lengthens the life of the parts.

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What are the initial costs of switching to LockJar products?

The initial costs of switching to Evans Jars are very low. The filling system required to fill the jars is very basic and already available in most shops. Also, Evans offers Service Technicians that will come to your shop and train your staff to ensure they have all the tools and equipment necessary to maintain the jars.

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