Device for guiding a drilling string during underwater drilling
First Claim
1. Device for guiding drilling strings for floating installations of the type comprising a platform and a well in said platform for the passage of tubular material, said device comprising a guide tube which consists of a flexible ring the internal diameter of which is constant over most of its length at a value from 1.1 to 1.4 times the external diameter of the joints of the drilling string, the external diameter of said flexible ring diminishing progressively from its median zone toward its two ends which constitute the flexible parts of the guide tube, the minimum thickness of said flexible ring being at least 4 mm, and the ratio of the thickness of the median zone of the guide tube to said minimum thickness lying between 4 and 25, while the ratio of the thickness in the median zone to the total length L of the tube varies from 0.002 to 0.010, a swivel joint connecting the median zone of said guide tube through lateral connecting means to the wall of said well, said swivel joint having an internal part contacting the outside of the ring and defining a spherical surface engaged in an external part, said external part being connected to the platform by means of longitudinal connecting means.
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Abstract
Device for guiding a drilling string from a floating drilling rig comprises a flexible guide tube having an inner diameter which is constant and an outer diameter which decreases progressively from its median zone toward each end, the median zone being connected by swivel means to lateral and longitudinal members connected to the floating drilling rig.
This device is especially adapted for floating drilling rigs having a well through which the string descends.
24 Citations
13 Claims
- 1. Device for guiding drilling strings for floating installations of the type comprising a platform and a well in said platform for the passage of tubular material, said device comprising a guide tube which consists of a flexible ring the internal diameter of which is constant over most of its length at a value from 1.1 to 1.4 times the external diameter of the joints of the drilling string, the external diameter of said flexible ring diminishing progressively from its median zone toward its two ends which constitute the flexible parts of the guide tube, the minimum thickness of said flexible ring being at least 4 mm, and the ratio of the thickness of the median zone of the guide tube to said minimum thickness lying between 4 and 25, while the ratio of the thickness in the median zone to the total length L of the tube varies from 0.002 to 0.010, a swivel joint connecting the median zone of said guide tube through lateral connecting means to the wall of said well, said swivel joint having an internal part contacting the outside of the ring and defining a spherical surface engaged in an external part, said external part being connected to the platform by means of longitudinal connecting means.
Specification