Abstract: Method intended for automatic control of an underwater pipe for connecting the lower end of the pipe to a wellhead, wherein the following stages are carried out: Stage 1: determining a mathematical model expressing the position of the lower end of the pipe as a function of the position of the upper end of the pipe, Stage 2: determining a reference path leading to the wellhead, Stage 3: from the mathematical model determined in stage 1, determining control laws allowing to control the path of the lower end of the pipe, Stage 4: applying determined motions to the upper end of the pipe so that the position of the lower end is as close as possible to the reference path determined in stage 2.

Abstract: Method intended for automatic control of an underwater pipe for connecting the lower end of the pipe to a wellhead, wherein the following stages are carried out: Stage 1: determining a mathematical model expressing the position of the lower end of the pipe as a function of the position of the upper end of the pipe, Stage 2: determining a reference path leading to the wellhead, Stage 3: from the mathematical model determined in stage 1, determining control laws allowing to control the path of the lower end of the pipe, Stage 4: applying determined motions to the upper end of the pipe so that the position of the lower end is as close as possible to the reference path determined in stage 2.

Abstract: A method for the improvement of performances involves a drilling model wherein the model takes account of the effects of the destruction of a rock (2) by a cutter (1) fastened to a bit body (3) driven in rotation and the effects of the removal of rock cuttings by a fluid, by calculating a material balance from the production of cuttings by the cutter that has penetrated the rock by a depth .delta., a bed of cutting of thickness l, a fluid strip of thickness h between the bed of cuttings and body (3), the fluid strip having a cuttings concentration c.