Logging While Tripping-A New Alternative in Formation Evaluation
Notice bibliographique
Résumé
Abstract Logging While Tripping (LWT) is a recent development in formation evaluation technology that provides a means by which open hole logs are obtained more quickly and with less risk than is currently possible using conventional wireline or measurement-while-drilling techniques. LWT Services Inc., a Calgary based company, has developed this new approach to the logging process which involves using specially modified drill collars and memory-based logging tools positioned within the drillstring to record log data as drillpipe is tripped out of the well. LWT tools are deployed and retrieved from the drillstring only when log data is required. After the data is acquired and the tools retrieved from the well, casing can be run without an additional hole-conditioning trip, saving considerable rig time. Risk is minimized because logging tools are not exposed to the open wellbore, but stay protected inside the drillstring. Service quality is reviewed by showing examples dealing with data quality and depth control. While LWT's compensated neutron provides an open hole quality measurement, some correction is needed to provide absolute porosity values in varying borehole sizes. Depth control examples compare favourably to wireline conveyed logs with an accuracy approaching +/- 1 m per 3,000 m of total depth. A few applications for this new technology are anticipated to be:Horizontal wells which are currently not evaluated due to the prohibitive cost and risk associated with pipe conveyed and MWD/LWD systemsReconnaissance logging, done at any time throughout the drilling of the well, will enable geologists to identify zones and monitor well trajectoryUnderbalanced, air-drilled wells can be logged as they are drilled, thereby eliminating the need to run open hole logs under pressure. Presently, LWT Services Inc. is working on a prototype 1 11/16 in. induction tool. In order to make induction measurements from inside the drillstring, a nonconductive composite drill collar has been constructed, tested, and successfully drilled 850 ft. in a test well in Oklahoma. Another development includes a compensated photoelectric density tool. Background Logging While Tripping (LWT) represents a new approach in the process of open hole data acquisition. LWT makes use of memory-based logging tools positioned in the drillstring to record data as drill pipe is tripped out of the well. Unlike measurement-while-drilling tools, LWT tools are not a permanent part of the drillstring but instead are deployed and retrieved from the drillstring only when log data is required. Currently, LWT provides FIGURE 1: LWT operation. (Available in full paper) compensated neutron and gamma ray services while the dual induction and photoelectric density are under development. While in its early stages of development, LWT's technology is aimed at providing drillers with significant cost savings in the area of open hole data acquisition. These cost savings will be realized in two principal areas:Decrease in rig time for the logging process and,Decrease in risk of tool loss or damage downhole. This paper presents an overview of LWT's operation, service quality, and applications supported by several examples. In closing, a brief review of future prospects is presented.
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Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,003 | 0,005 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,004 | 0,004 |
| Études des sciences et des technologies | 0,001 | 0,001 |
| Communication savante | 0,004 | 0,003 |
| Science ouverte | 0,001 | 0,002 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,006 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».