TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractA dynamic model for underbalanced drilling has been developed in a joint industry project. The model is of use for planning an operation, and especially evaluations of dynamic pressure and flow effects. Use of the model can help prevent excessive pressure transients during operations, which will have negative effects on well productivity.Experiments have been performed in a vertical, extensively instrumented, test well. The experiments focused on dynamic operations; such as kick-off or unloading, changes in liquid and/or gas injection rates and pipe connections as well as "steady state" periods. The tests were performed with either "parasite string" gas injection, or drillstring gas injection.Simulations with the dynamic model has been performed, using experimental quantities as input (geometries, liquids, rates etc.) Results show that the model performs very well for "parasite string" gas injection. For drilling gas injection system, the model performs well for low and medium gas rates. For very high gas rates, there is still room for improvements.

Copyright 1~, lA~SPE Drilling tifa This paper was prepared for prewnt8tion q t the 1~lAOC/SPE Drilling Wferenm held in Dallas, Texas M March 1S98, This papsr wc -Iected for pre=ntation by an lA~SPE Progr8m -mittes follting review of information contitned in an abtict submittsd by h author(s), Contents of the paper, as presented, have not~n rsviawsd by the International Association d Drilling Contractor or the We& d P*leum Engineer8 and are subject to corr-"on by the author(s), The material, as presentsd, dms not nsces-rily reflect any position of the IAOC or SPEf their officers, or members. Papar$ presented at the IAWSPE meetings are subject to publication revisw by Editorial Mmitteas of the IADC and SPE, Electronic reproduction, distribution, or storage of any part& this~~r for commercial purposes without the wi~en consent of the Scciety of Petroleum Engineers is prohibited, Permission to reprcduce in print is restricted to an abstract of not more than~words, illustrations may not be copied. The abstraot must contain conspicuous ackdedgment of Mere and by whom the papsr was presented. Write Librarian, SPE, PO, h @32S3e, Richardson, TX 75C333SW, US.A, tix 01-972-952.9435, AbstractA part of the planning of underbalanced operations is to estimate drilling and production related parameters. Wellbore pressure and fluid phase velocity profiles, hydrocarbon production management mechanisms and injection gas requirements are necessary for designing underbalanced drilled wells. A steady state underbalanced drilling sofiware tool has been developed by Shell to assist their well engineers in planning and executing underbalanced operations. The simulator has been validated and its accuracy proven with field data comparisons. The accuracy was within the range of the intended area of application and has indicated less than 10% difference in measured wellbore pressures. The objective of the software development is to release the simulator to the industry. Concurrently the model will be developed further and its accuracy improved. A concern at the moment, is the limited number of wells drilled underbalanced with stilcient data gathered to allow extensive simulator comparison, To obtain an overview of capabilities and applicability of presently on the market available simulators, a thorough comparison between models is recommended.

This paper describes the development and use of the International Coiled Tubing Association (ICoTA) guidelines for training and competence for CT drilling operations. The lack of training standards within the coiled tubing industry is well recognised. In order to redress this and develop standard training requirements for CT operations ICoTA set up a workgroup in 1997. The aim of this workgroup was to identify the minimum required skills and knowledge for safe and efficient CT operations, to aid the training of personnel and enhance operational safety and efficiency. Initially CT Drilling operations are addressed as this is the area where the lack of a structured approach to training and competence is most apparent. The paper discusses the results from this workgroup, and presents the suggested outcome. The approach to wellsite competence is based on competence presence, and is not related to people or job functions. Three levels of competence are recognised; ability to execute, ability to supervise execution and ability to assist. The guidelines take into account; applicability worldwide for all CT drilling operations, on all types of CT units, and different organisational structures. Several examples of training requirements will be given for various CT drilling operations in order to illustrate how this document may best be used in practice. Definition: This paper is about training, competency and experience. To achieve a common understanding of the definition of competency it is taken as meaning: Competency – " Ability to perform the activity in the workplace consistently to the required standard ". In this context, competency consists of proven knowledge, skills and experience.

This paper examines the technologies required to develop a Reeled Monodiameter Well, a well using expandable coiled casing that maintains a single diameter of well bore throughout. However, a Reeled Monodiameter well will not be available to the industry tomorrow. Slotted expandable tubulars were introduced to the industry in the recent past and are now finding commercial applications. The concept of solid expandable tubulars for oil well applications is the next logical step of this technology. Joint Venture companies have recently been established to develop the concept of solid expandable tubulars and bring them to the market place. Consideration of the whole package reveals that there are various ways of achieving the end objective as described in this paper. There are still key technological challenges, notably in the areas of expandable casings, annular isolation techniques, over gauge hole drilling and novel hanger systems that will have to be addressed before this process becomes everyday reality. Possible solutions to these challenges are presented.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThis paper describes the development and use of the International Coiled Tubing Association (ICoTA) guidelines for training and competence for CT drilling operations. The lack of training standards within the coiled tubing industry is well recognised. In order to redress this and develop standard training requirements for CT operations ICoTA set up a workgroup in 1997. The aim of this workgroup was to identify the minimum required skills and knowledge for safe and efficient CT operations, to aid the training of personnel and enhance operational safety and efficiency. Initially CT Drilling operations are addressed as this is the area where the lack of a structured approach to training and competence is most apparent.The paper discusses the results from this workgroup, and presents the suggested outcome. The approach to wellsite competence is based on competence presence, and is not related to people or job functions. Three levels of competence are recognised; ability to execute, ability to supervise execution and ability to assist. The guidelines take into account; applicability worldwide for all CT drilling operations, on all types of CT units, and different organisational structures. Several examples of training requirements will be given for various CT drilling operations in order to illustrate how this document may best be used in practice. Definition:This paper is about training, competency and experience. To achieve a common understanding of the definition of competency it is taken as meaning:Competency -" Ability to perform the activity in the workplace consistently to the required standard ". In this context, competency consists of proven knowledge, skills and experience.