Verfahren zum Zurueckholen mindestens eines Teils einer Unterwasser-Produktionsbohrlochkopfbaugruppe zur Wasseroberflaeche

• Main Author: HENRY PETERSEN,WILLIAM
• Format: Patent
• Language: German
• Published: 04.12.1969
• Subjects: EARTH DRILLING; EARTH DRILLING, e.g. DEEP DRILLING; FIXED CONSTRUCTIONS; MINING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR ASLURRY OF MINERALS FROM WELLS

1,256,314. Wells &c. SHELL INTERNATIONAL RESEARCH MAATSCHAPPIJ N.V. 22 May, 1969 [24 May, 1968], No. 26208/69. Heading E1F. A production wellhead assembly 25 forming part of a subaqueous wellhead structure 18 is retrieved by lowering retrieval means 34 and means 35 carrying guidelines 42, 43 into engagement with the wellhead structure and withdrawing the assembly 25 together with the retrieval means along the guidelines. The guidelines are held taut while the retrieval means is lowered on a drill pipe 33, by constant tension hoists 44, 45. A sonar device 46 and/or TV camera (47) Fig. 2 (not shown) facilitate final positioning of the retrieval means over the wellhead. Angular orientation of guideline housings 36, 37 with guideposts 20, 21 may be achieved by a pin on the retrieval means co-operating with a slot on the structure 18. When the retrieval means has been locked in position on the assembly 25 the guidelines are anchored by releasing the tension in the hoists so that latches in the flared ends 40, 41 of connector elements 38, 39 engage the guideposts. The well is then remotely closed down and the assembly 25 disconnected from the remainder of the wellhead structure prior to retrieval.