Method for detecting gain or loss of drilling fluid in a drilling installation associated calculation system and associated drilling installation

A method for detecting gain or loss of drilling fluid in a drilling installation, said drilling installation comprising a drilling pipe, drilling fluid pits, and a hydraulic connection between the pits and the drilling pipe,

• said method comprising:
• providing at a plurality of measuring times (tm) of a first period, a set of measurement values (vai,m;
• vcj,m) representative of a volume of drilling fluid in each of the pits belonging to at least a predetermined group of pits;
• then
• based on volume measurement values, identifying volume variations occurring during the first period for the pits of the predetermined group, each volume variation of a pit being associated with a volume variation period;
• calculating, for each measuring time (tm), a corrected cumulated volume of drilling fluid (V′m) for the pits of the predetermined group, wherein the corrected cumulated value is determined based on the identified volume variation occurring in at least a sub-group of the predetermined group, and
• estimating a first value (Am) for a gain or loss of drilling fluid at a measuring time (tm) by comparing the corrected cumulated volume (V′m) with an expected value (V0), comprising, for each pit, converting the function [measuring time (tm)/measurement value (vai,m, vcj,m, vik,m)] into segments separated by change-points according to a segmentation model, the volume variation periods for each pit being defined by the change-points.

A method for detecting gain or loss of drilling fluid in a drilling installation, said drilling installation comprising a drilling pipe, drilling fluid pits, and a hydraulic connection between the pits and the drilling pipe,

• said method comprising:
• providing at a plurality of measuring times (tm) of a first period, a set of measurement values (vai,m;
• vcj,m) representative of a volume of drilling fluid in each of the pits belonging to at least a predetermined group of pits;
• then
• based on volume measurement values, identifying volume variations occurring during the first period for the pits of the predetermined group, each volume variation of a pit being associated with a volume variation period;
• calculating, for each measuring time (tm), a corrected cumulated volume of drilling fluid (V′m) for the pits of the predetermined group, wherein the corrected cumulated value is determined based on the identified volume variation occurring in at least a sub-group of the predetermined group, and
• estimating a first value (Am) for a gain or loss of drilling fluid at a measuring time (tm) by comparing the corrected cumulated volume (V′m) with an expected value (V0), wherein the corrected mud volume (V′m) is calculated based on, for each volume variation involving in at least a pit of the sub-group:
• a compensation during volume variation, for volume variation having an associated volume variation period including the measuring time tm, and/or
• a compensation after volume variation for volume variation having an associated volume variation period that ends before the measuring time tm.