The economical completion of the Bakken Shale often dictates the drilling of a horizontal wellbore. A horizontal wellbore placed through a naturally fractured shale formation introduces drilling problems of wellbore collapse, the opening of existing natural fractures, or creation of fractures. Knowledge of magnitude and direction of the in-situ stresses is important in determining the optimum direction to drill a horizontal wellbore. The stress direction is important because a horizontal wellbore has its maximum stability when it is in the direction of minimum principal in-sttu stress. Combining the in-sttu stress magnitude data from microfracture stress tests, the in-sttu stress direction from anelastic strain recovery and differential strain analysis, and mechanical properties from laboratory tests, one can determine the minimum and maximum allowable drilling mud weights and optimize wellbore direction if necessary.1 The microfracture stress test was used to determine stress magnitude. Successfully performing the microfracture tests has meant overcoming problems inherent in performing these tests at high temperatures and high injection pressures associated with deeper wells in addition to concerns with the naturally fractured shale's stability. Some special equipment was required for the tests. Special surface injection equipment, developed in recent years was used to perform the tests. Standard downhole drillstem testing tools were deemed to be the most appropriate and were used in a special configuration to isolate the zones of interest and to overcome some of the problems associated with temperature and pressure (increasing depth), the natural fractures, and problems with borehole sloughing. Problems peculiar to naturally fractured shale affected the anelastic strain recovery (ASR) and differential strain analysis (DSA) testing. This paper presents a systematic approach for determining in-sttu stress field direction and magnitude and applying these measurements to determining the minimum and maximum limits of mud weight and wellbore direction for optimum drilling design in the Bakken Shale.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractSince its introduction, over 700 alternate path sand control completions have been implemented around the world ranging from single zone cased hole gravel-packs to multi-zone fracpacks and fibre optic (DTS) enabled open hole horizontal completions. Over the last six years, the alternate path system has been field proven to provide high reliability in achieving complete packs as well as additional features allowing simultaneous cake cleanup, shale bypass and other contingencies that enable "doing it right the first time" in deep-water/subsea completions where interventions tend to be economically and logistically prohibitive.This paper provides a critical review of those completions, capturing both successes and failures, along with the lessons learned in their design, execution and evaluation in relation to completion efficiency in sanding reservoirs. Furthermore, it details future development work and enablers that will allow the use of alternate path technology as the mainstay of intelligent well solutions, geometrical design improvements to provide optimal aspect ratios in the wellbore and its applicability in conjunction with water packing.

This paper was selected for preaantafion by an SPE ProgramCommittee following reviaw of informationcontained in an abstract submiffad by the .. . ,. aumor@). -ms UI me I.WIJUI,~r=.=,, .. . . ... . ---------. . .. . ------. . . -..s..+~h..-@ he~n revi@w@by the~efy of Patrijaum Engineers and are subject to @JrrSCtiOn by the author(a).The materiel, as presented, does not necessarily reflect any poeifiin of the S6ciefy of Petroleum Engineers, ita offiiara, or members. %pera presented at SPE meetings are subject to publicatlcmreview by Editorial Commineea of the Sodety of Petroleum Enginwra. Permieaion to coPy is reetricfedto an abstract of not more than 200 words. Illustratkmsmay net be copied. The abstract ahoufdcontain conspicuousacknowledgmentof where and by whom the paper is presented. Write Publicmiona Manager, SPE, P.O. Sox SS2SS6, Richardson, TX 7S083-SS36. Telex, 7S0989 SPEDAL.

Summary Brine displacements were one of several areas of focus in a continuous process to optimize completion methodology in Amerada Hess's Ceiba project wells, located in deepwater offshore Equatorial Guinea. The time between making up the cleaning string and laying it down, after displacement and filtration operations are completed, can exceed two days and cost U.S.$500,000. It is imperative that wellbore-cleaning operations are performed efficiently and correctly the first time. Amerada Hess and its brine suppliers, working together in a joint task force, have taken specific steps to minimize the time required for displacement and filtration operations. Introduction The Ceiba field in deepwater Equatorial Guinea was discovered in mid-1999 by Triton Energy Ltd., now Amerada Hess. To date, 20 wells have been completed, and three wells have been recompleted. Ongoing development of the field still continues at this time. Five of the wells were completed as openhole gravel-packed producers. The others were cased-hole producers or injectors. The initial average pore pressure in the field was 8.7lbm/gal, and the majority of wells in the field were completed in a 9.0 to9.2-lbm/gal CaCl2 brine. This fluid was selected because of its minimal damage effect during core tests and its ready availability at stock points in the west Africa operating area. All wells were drilled through the pay interval by use of mineral-oil-based mud. The Ceiba field lies in approximately 800 m of water. The wells flow through individual subsea flowlines for 8 to 11 km to a floating-production, storage, and offloading unit that was positioned to receive first oil in the late fall of 2000.1 The semisubmersible Sedco 700 has been on location in the field since the spring of 2000 and has drilled the majority, and completed all, of the Ceiba development wells. As part of a continuing improvement program used throughout the development of Ceiba, a critical review of brine-displacement practices was performed to optimize this process. A review of cased-hole completions by the taskforce indicated room for improvement in our displacement process and chemical usage. At the time the task force was formed, the average displacement took 25or more hours, with up to 4,000 bbl of completion brine discarded because of poor quality and filtration problems. This paper examines the stages of mud-to-brine displacement used in the cased-hole completions of the Ceiba deepwater development and demonstrates how these stages were adjusted in their relationship to one another to make a more efficient displacement. Data are presented to show simplification of procedures, improved mud-solids removal, shorter filtration time, reduced loss of brine, and shorter rig timeover the course of the development. These modifications and changes had a major impact on time and cleaning efficiency. Please note, Ceiba openhole-completion displacements are not addressed in this paper.

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