No abstract

Copwght 19S8, lADC/SPE Asia Pacific Drilling TefinologyThis paper was~psred fw presentaticm at the 1998 lADC/SPE Asia Pacific Driffing ConferenM held in Jakarta, Indowsia, 7-9 Septembr 1998. This paper was selasted fw presentation by an lADC/SPE Program Committee following review of infoimatim untained in m abstract submittad by the author(s). Contents of the paper, as presented, have not been reviewed by the International Association of Drilling Ccfdfactws or the Society of Petroleum Engineers and are subject to Wedicm by ths author(s). The material, as presented, does not necessarily reflect any position of the IADC or SPE, their ofti~rs, w members. Papers psented at the lADC/SPE meetings are subjest to publication review by Editorial Committees of the IADC and SPE. Electronic reprodudfon, disbibution, or slorage of any part of this papar for commercial purposes without the written cnnsent of the Society of Petroleum Engineers is prohibited, Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not bs copied. The abstrad must cQntain Cnnsplcuous acknowledgment of wbre and by whom the paper was presentd write Librarian, SPE, PO. Box 833836, Richardson, TX 75083-3836, U. S.A., fsx 01-972-9S3-9435. AbstractRecent increase in application of coiled tubing for horizontal wells and in particular underbalanced drilling triggered the necessity of a powefil downhole motor. More often downhole motor stalling and motor replacement is a problem when using with coiled tubing drilling system. To enhance the technology and make the system effective, optimization of drilling parameters is essentially required. The frequent motor replacement during the operation incrementally increases the operating cost despite deriving potential benefits from coiled tubing drilling. The key to improved coiled tubing drilling system is a unified system approach that encompasses motor and bit. This paper presents an analytical study on the optimization of motor performance and drilling parameters. A new simple test called wear-o~f test is defined to establish an operating window. The practical usefulness of the theory, backed by the fundamental and optimal analysis for roller cone and diamond bits, is demonstrated with numerical examples.