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FP5

HOT DRY ROCK ENERGY Sintesi della relazione

Project ID: ENK5-CT-2000-00301
Finanziato nell'ambito di: FP5-EESD
Paese: France

Development and demonstration of inflatable metal packer technology

The developments already undertaken by MeSy and Socomine on the completion of the well GPK2 in 1999 were pursued and led to the development of packers with a larger diameter with cupper-nickel shell which is inflated and expanded through high-pressure cement injection. The existing model already tested in 1999, operational in an 81/2" diameter wells, was modified to be able to seal 9 5/8" diameter casings in wells drilled with a diameter of 12 1/4¿.

The main problem of this development was to balance the larger hydraulic forces associated with the increase of hole size and packer diameter and still maintain the packer OD at the level of the OD of the casing couplings. Eight prototypes were successfully tested in the workshops of the MeSy company, co-owner of the patent for this equipment. The tests showed that the shells start to expand below 10 MPa and that the internal overpressure while setting the element should not exceed 16 MPa. Two packers of this type were installed without any obvious problem at the bottom of the 9 5/8" casing in the well GPK3.

Two further packers were used with the same for the completion of well GPK4. Unfortunately, in this case the situation was more complicated as it was not possible to fully complete the cementation programme as the injection pressure started to rise before the full cement volume could be pumped into the annulus. Some 10 m3 (of 40 m3 total) were left inside the casing, string. It appears that the casing elongated while lifting the cement in the annulus and the casing shoe sat down on the 8 1/2¿ hole reduction thus preventing the circulation of the final 8.79 m3 of cement. At this point, the pressure increased to above 200 bars immediately and the packers were set. With the premature setting of the packers, approximately 10 m3 of cement were left inside the casing,, some 8 m3 more than planned.

The original plan was to bring the top of the cement in the annulus up to 3960 meters. Approximately 31 m3 of cement were circulated around the casing before the packers were set, this placed the top of the cement around 4130 meters according to the Schlumberger logging measurements.

This cement top was later verified through logging operations. There were no indications that the packers had not been set.

Informazioni correlate

Reported by

GEIE Exploitation Minière de la chaleur
Route de Soultz - BP 38 -
67250 KUTZENHAUSEN
France