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U.S. Department of Energy
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Coiled tubing workover saves horizontal well in Lake Maracaibo

Conference ·
OSTI ID:434038

A slotted liner horizontal completion became stuck while being run. Inflatable packers were to be used to isolate the productive interval from a water-bearing, unconsolidated sand in the curved section of this well. While personnel were deciding how to cement the well, the liner was left in the hole with the inflatable packers unset, and the production tubing was run. Coiled tubing was used to log the well, isolate the productive interval, and remove damage to restore well productivity. Personnel considered all possible options, and a thorough decision-making process guided the workover. Because of severe lost-circulation problems, extensive ``what if`` scenarios were made and updated daily for the engineers on location. Service company and oil company personnel worked together to guarantee the job designs were practical and did not exceed the limits of the equipment on location. Computer simulations of all operations were run to allow corrective action to be taken if unusual circumstances arose. All fluids were thoroughly laboratory tested and witnessed by oil company personnel to ensure job success. Problems on the job included lost circulation, locating the exact positions of the packers and water zone, ensuring correct cement placement, removing mud and workover fluids without damaging the squeeze, and bad weather on Lake Maracaibo. Advantages and disadvantages of all the solutions that were considered are included to assist anyone in a similar situation. Post-job oil production has stabilized at 900 BOPD with no water or sand production. Careful job planning and the versatility of coiled tubing saved this well and proved economical with an estimated payout of 33 days, assuming a price of $12 per barrel of oil.

OSTI ID:
434038
Report Number(s):
CONF-960525--
Country of Publication:
United States
Language:
English

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