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1. (WO2010083180) ATTENUATION OF UNWANTED ACOUSTIC SIGNALS BY SEMBLANCE CRITERION MODIFICATION
Latest bibliographic data on file with the International Bureau

Pub. No.: WO/2010/083180 International Application No.: PCT/US2010/020835
Publication Date: 22.07.2010 International Filing Date: 13.01.2010
IPC:
E21B 47/14 (2006.01) ,E21B 47/16 (2006.01) ,G01V 1/40 (2006.01)
E FIXED CONSTRUCTIONS
21
EARTH OR ROCK DRILLING; MINING
B
EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
47
Survey of boreholes or wells
12
Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling
14
using acoustic waves
E FIXED CONSTRUCTIONS
21
EARTH OR ROCK DRILLING; MINING
B
EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
47
Survey of boreholes or wells
12
Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling
14
using acoustic waves
16
through the drill string or casing
G PHYSICS
01
MEASURING; TESTING
V
GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
1
Seismology; Seismic or acoustic prospecting or detecting
40
specially adapted for well-logging
Applicants:
SERVICES PETROLIERS SCHLUMBERGER [FR/FR]; 42 Rue Saint Dominique 75007 Paris, FR (FR)
SCHLUMBERGER CANADA LIMITED [CA/CA]; 525 - 3rd Avenue S.W. Calgary , Alberta T2P 0G4, CA (CA)
SCHLUMBERGER HOLDINGS LIMITED; P.O. Box 71 Craigmuir Chambers Road Town Tortola Virgin Islands, British, VG (GB, JP, NL)
SCHLUMBERGER TECHNOLOGY B.V. [NL/NL]; Parkstraat 83-89 2514JG The Hague Netherlands, NL (AL, AM, AU, AZ, BG, BY, CO, CZ, DE, DK, GR, HU, ID, IE, IL, IT, KG, KP, KR, KZ, LT, MD, MX, MY, NO, NZ, OM, PL, RO, RU, SI, SK, TJ, TM, TN, TR, TT, UA, UZ, ZA)
PRAD RESEARCH AND DEVELOPMENT LTD; P.O. Box 71 Craigmuir Chambers Road Town Tortola Virgin Islands, British, VG (AE, AG, AO, AT, BA, BB, BE, BF, BH, BJ, BR, BW, BZ, CF, CG, CH, CI, CM, CN, CR, CU, CY, DM, DO, DZ, EC, EE, EG, ES, FI, GA, GD, GE, GH, GM, GN, GQ, GT, GW, HN, HR, IN, IS, KE, KM, KN, LA, LC, LK, LR, LS, LU, LV, LY, MA, MC, ME, MG, MK, ML, MN, MR, MT, MW, MZ, NA, NE, NG, NI, PE, PG, PH, PT, RS, SC, SD, SE, SG, SL, SM, SN, ST, SV, SY, SZ, TD, TG, TZ, UG, VC, VN, ZM, ZW)
BOSE, Sandip [IN/US]; US (UsOnly)
DUMONT, Alain [FR/JP]; JP (UsOnly)
VALERO, Henri-Pierre [FR/US]; US (UsOnly)
Inventors:
BOSE, Sandip; US
DUMONT, Alain; JP
VALERO, Henri-Pierre; US
Agent:
RAYBAUD, Helene; Schlumberger Doll Research Intellectual Property Law Department One Hampshire Street Cambridge, Massachusetts 02139, US
Priority Data:
12/352,84813.01.2009US
Title (EN) ATTENUATION OF UNWANTED ACOUSTIC SIGNALS BY SEMBLANCE CRITERION MODIFICATION
(FR) ATTÉNUATION DES SIGNAUX ACOUSTIQUES NON VOULUS PAR MODIFICATION DES CRITÈRES DE SEMBLANCE
Abstract:
(EN) Methods and related systems are described for modified semblance criterions based on the approach of thresholding the signal energy. A first criterion is derived by posing the problem as that of detecting a signal with energy (or amplitude) greater than the specified threshold and deriving the generalized likelihood ratio test statistic. A second criterion is derived using the same method by posing the problem as that of rejecting any signal with energy (or amplitude) below a specified threshold and detecting it if its energy is above another threshold greater than or equal to the first. These appropriately modify the original semblance criterion which is shown to be equivalent to the GLRT test statistic in the absence of any threshold on the signal amplitude. In addition simpler modifications are also described. Tests on synthetic data illustrate the effectiveness of all these modifications which perform comparably well at suppressing unwanted arrivals while accurately processing the desired signals.
(FR) La présente invention a pour objet des procédés et des systèmes associés pour des critères de semblance modifiés sur la base de l'approche des seuils de l'énergie de signal. Un premier critère est obtenu en définissant le problème comme celui de la détection d'un signal dont l'énergie (ou l'amplitude) est supérieure au seuil spécifié et en en déduisant la statistique de test de rapport de ressemblance généralisée. Un second critère est défini au moyen du même procédé en définissant le problème comme celui de rejeter tout signal dont l'énergie (ou l'amplitude) est au-dessous d'un seuil spécifié et de le détecter si son énergie est supérieure à un autre seuil supérieur ou égal au premier. Ces critères modifient de manière appropriée le critère de semblance d'origine dont on montre qu'il est équivalent à la statistique de test GLRT en l'absence de tout seuil sur l'amplitude du signal. De plus des modifications plus simples sont aussi décrites. Des tests sur des données synthétiques illustrent l'efficacité de toutes ces modifications qui sont aussi performantes pour la suppression des arrivées non voulues tout en traitant de manière précise les signaux souhaités.
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Designated States: AE, AG, AL, AM, AO, AT, AU, AZ, BA, BB, BG, BH, BR, BW, BY, BZ, CA, CH, CL, CN, CO, CR, CU, CZ, DE, DK, DM, DO, DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT, HN, HR, HU, ID, IL, IN, IS, JP, KE, KG, KM, KN, KP, KR, KZ, LA, LC, LK, LR, LS, LT, LU, LY, MA, MD, ME, MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI, NO, NZ, OM, PE, PG, PH, PL, PT, RO, RS, RU, SC, SD, SE, SG, SK, SL, SM, ST, SV, SY, TH, TJ, TM, TN, TR, TT, TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, ZW
African Regional Intellectual Property Organization (ARIPO) (BW, GH, GM, KE, LS, MW, MZ, NA, SD, SL, SZ, TZ, UG, ZM, ZW)
Eurasian Patent Organization (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM)
European Patent Office (AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT, LU, LV, MC, MK, MT, NL, NO, PL, PT, RO, SE, SI, SK, SM, TR)
African Intellectual Property Organization (BF, BJ, CF, CG, CI, CM, GA, GN, GQ, GW, ML, MR, NE, SN, TD, TG)
Publication Language: English (EN)
Filing Language: English (EN)
Also published as:
NO20110886CA2750415