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.
