Kuwait Oil Company(KOC)'s massive expensive efforts, to control extraneous source water invasion, by casing repair in multireservoir ageing wells particularly run by electrical submersible pump(ESP), is not paying expected dividend. To achieve negative casing integrity is a challenge in ageing wells and achievable negative casing integrity is very low (300-900 psi) which does not sustain against ESP's high drawdown (1000-4500 psi) which has been established from workover data accumulated over a prolonged period reveals leakage from previous squeezed zones, corroded/weak casing and liner top. The leakages are refixed with multiple cement squeezes with available recipes. spending a staggering repair cost of $0.5 million USD/well on an average. But after a short span of the potential productive life of the reservoir, significant water production starts from extraneous sources evident from intake pressure and flow rate variation from the reservoir potential, thereby necessitates intervention. This cycle of casing repair and failure of casing integrity goes on involving high magnitude of recurring losses incurs on establishing casing integrity, unsustainable production and excess water handling. Besides, economically unrepairable wells are forced to compromise on production by reducing casing size to avoid abandoning/drilling fresh wells. Such unsustainable production scenario, likely to affect KOC's 2020 target, highlightens the desperate need to have the solution.An innovative completion solution to mitigate this potentially catastrophic issue will be presented and the paper will discuss the details of the tools, equipment adopted to achieve the objective.Apart from expected huge saving of over $ 21 million USD/anum to KOC this innovative completion solution will definitely benefit the industry in dealing with the issues of ageing wells.
This paper highlights the design, planning, challenges, operational complications and successful execution of coil tubing application in active deep well in West Kuwait. The aim of coil tubing job is to clear the pipe from inside to recover the stuck pipe to eliminate the sidetrack in highly pressurized complicated Salt/Anhydrite sequence. In one of the West Kuwait wells, during drilling the well got a kick with high gain rate. During shutting in and at starting of killing the well, it was observed that the pipe & annulus were plugged. Pipe puncture job was carried out & the well was killed off bottom with 19.7 ppg mud. Throughout running in hole with the free point locator tool prior to back off job, the held up was observed at 12,490 ft i.e. 1,300 ft above the bit. It was then selected to clean inside drill pipe to avoid sidetracking. The well conditions presented challenges to the design and operation of coil tubing in this well. Challenging factors included: Use of high weight and yield strength, 15 ksi coil tubing, high mud density of 19.7 ppg, high pumping pressures, deep well, ID restriction 3 ½ in DP with 2 in ID, active well, deviated well of around 57 degrees. The coil tubing job design was critical for success of the operation. It included selection and analysis of coil tubing material, size, wall thickness; managing potential coil tubing burst and collapse pressures, calculation of coil tubing stretch, circulation pressure with high density mud, coil tubing force analysis, and wellbore solids removal with very minimum clearance & minimum pumping rate. Initial simulations with 1.5 in coil tubing showed that circulation pressures would go above the 15 ksi rating. It was then decided to switch to high pressure 1.75 in coil tubing with which simulation showed that pressures at the rotating joint would be at 8,000 psi, using a jetting nozzle. While lowering with jetting nozzle, held up was observed at overshot due to the deviation. After changing jetting nozzle with the 1 11/16 in kick off tool, the coil tubing was able to pass through the gelled mud with circulation. To keep under check, high circulating pressure with aid of hydraulics analysis, related to dynamic circulation rate to 0.2 bpm at 7,500 psi & static rate to 0.35 bpm with 8,500 psi. Resulting in successfully clearing the drill pipe from inside to 12,974 ft, below the observed settling of hard barite. Coil Tubing intervention with the restricted pipe diameter and heavy mud at high inclination well using a kick off tool was done for the first time in Kuwait. It achieved the purpose of cleaning the pipe to definite depth enabling back off operation below the jar & enhanced the chance of pipe recovery.
In modern industries automated machines are considered as one of the most important constituent in improving productivity. Gundrills are special cutting tools used for deep-hole drilling to achieve a depth to diameter ratio ranging up to 300:1. Gundrill production is largely dependent on manual operations owing to the manufacturing complexities. The total throughput time in gundrill manufacturing is significantly affected by the manual grinding process. This paper presents a study on the various grinding operations and identifies bottlenecks during gundrill production. Simulation is done in ARENA by Rockwell Automation Inc. for the manual process as well as for the automation required for the required for reduction in cycle time. Non-parametric tests are conducted for validating the ARENA model. Conclusions are drawn to automate the production aimed at reducing the cycle time while improving quality and EHS (Environment, Health, Safety) practice by eliminating tedious and repetitive operations. The present work serves as a benchmark approach for any manufacturing engineer intended to reduce the throughput time of any components.
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