New Innovative Wireline Jar Adds Significant Value by Reducing Fishing Cost

Abstract

This paper discusses a new, innovative tool, namely a hydraulic jar with a mechanical lock developed to run on wireline cable. The discussion addresses (1) the role and value of wireline jars in electric line operations, (2) technical features of the new wireline jar system with comments on its operation, and (3) a brief review of several of the many successful field applications. Getting stuck during a logging operation can add significant cost to a well. The new wireline jar has proven to be remarkably effective in freeing stuck wireline tools and preventing costly fishing operations. Freeing the tools also provides the opportunity to complete the required data acquisition as the instruments have historically not been damaged by jarring. In addition, the use of the wireline jarring method described in this paper allows operators to run relatively inexpensive free-fall wireline tools in areas that previously ? due to sticking problems ? have gone straight to drill-pipe-conveyed operations or logging while drilling (LWD) methods. A multi-conductor jar, called the LockJar®, has been in use for more than four years. The jarring system utilizes a proprietary-design LockJar and Enhancer, both of which remain passive until such time as they are needed. The LockJar can be pulled, without triggering, as hard as desired for durations shorter than the tool's time delay. Slacking off the string resets the LockJar so that it can be pulled again. Experience with this new technology has also led to discovery of valuable best practices for handling stuck tools, which has increased the number of freed tool strings. Among these best practices is the use of properly placed standoffs, particularly in inclined sections of wellbores. Experience with this new technology began in the GOM but the technology has quickly spread around the world to locations that experience problems with sticking during logging. In the GOM, several examples can be cited including a job where the LockJar was activated over 20 times in six different intervals; and still the well was successfully logged. This well was the very first in the field that was logged without a fishing job. Successes described in this paper include an example from the US Rockies and in Brazil and other international locations, such as West Africa, where the LockJar also freed tools on their very first run. Introduction Within wireline logging operations, it had generally been accepted that key seating was the primary reason for getting stuck. It was not known whether tension pulled on surface was actually reaching the top of the tool string because stress at the top of the string was not measured. Without this information, it was not possible to easily confirm whether the location of the sticking point was or was not up hole. The calculations required for determining the maximum pull available at the point in the well where the tool string was most likely stuck is time-consuming and tedious, adding to the overall time before activating a maximum pull. Thus, in many cases, by the time the location of the sticking point was determined, plenty of time to become more fully key seated had passed. With the introduction of the technology described in this paper, experience has shown that in most cases in wireline logging, the tools become stuck, not the wireline cable. This experience has led to the understanding that - similar to the case in drilling - the sooner one applies maximum overpull to the jars and toolstring after the toolstring becomes stuck, the better the chances of successfully freeing the tools. Fishing is costly at any time during well drilling and completion, including during logging operations. The costs in delays and in the value of lost or damaged equipment can easily run into the hundreds of thousands of dollars. Therefore, anything that contributes to freeing a stuck tool quickly and efficiently has the potential to save not only time, but money.

Using Wireline Standoffs (WLSOs) To Mitigate Cable Sticking

“…However, 11% of the jobs still required fishing operations. It should be noted that 50% of those 11% of jobs required fishing because of stuck cable (Evans, Brame, & Rose, 2007).…”

“…There have been a number of advances in wireline conveyance modeling, technologies, and techniques in recent years (Sarian, Varkey, Protasov, & Turner, 2013;Prasad, Castillo, & Elshahawi, 2012;Castillo & Wills, 2007;Evans, Brame, & Rose, 2007). However, it could be argued that diagnosing and mitigating cable sticking has not generally received the focus it has deserved.…”