Drilling problems

This term describes a situation whereby the drill string cannot be moved up or down or rotated anymore. The pipe can become stuck as a result of mechanical problems during 

Bottom hole assemblies and certain types of downhole equipment (e.g. logging tools, MWD tools) cost several US 100,000. Some logging tools will have radioactive sources which may need to be recovered or isolated for safety and legal reasons. However, prior to commencing fishing operations, a cost - benefit assessment will have to be made to establish that the time and equipment attributable to the fishing job is justified by the value of the fish or the cost of sidetracking the hole. 

Due to the different nature of junk a wide variety of fishing tools are employed. 

During drilling operations sometimes large volumes of drilling mud are lost into a formation. In this case normal mud circulation is no longer possible and the fluid level inside the borehole will drop, creating a potentially dangerous situation as described below. The formations in which lost circulation can be a problem are  

In the event of a sudden loss of mud In an Interval containing overpressures the mud column in the annulus will drop, thereby reducing the hydrostatic head acting on the formation to the point where formation pressure exceeds mud pressure. Formation fluids (oil, gas or water) can now enter the borehole and travel upwards. In the process the gas will expand considerably but will maintain its initial pressure. The last line of defence leff is the blowout preventer. However, although the BOP will prevent fluid or gas escape to the surface, closing in the well may lead to two potentially disastrous situations  

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An important safety feature on every modern rig is the blowout preventer (BOP). As discussed earlier on, one of the purposes of the drilling mud is to provide a hydrostatic head of fluid to counterbalance the pore pressure of fluids in permeable formations. However, for a variety of reasons (see section 3.6 Drilling Problems ) the well may kick , i.e. formation fluids may enter the wellbore, upsetting the balance of the system, pushing mud out of the hole, and exposing the upper part of the hole and equipment to the higher pressures of the deep subsurface. If left uncontrolled, this can lead to a blowout, a situation where formation fluids flow to the surface in an uncontrolled manner. 

C. Durand, A. Onaisi, A. Audibert, T. Forsans, and C. Ruffet. Influence of clays on borehole stability A literature survey Pt 1 Occurrence of drilling problems physico-chemical description of clays and of their interaction with fluids. Rev Inst Franc Petrol, 50(2) 187-218, March-April 1995. 

The problems in the text fall into two categories drill and complex. Drill problems, which appear throughout the text and at the end of each chapter, test your knowledge of one fact or technique at a time. You may need to rely on memorization to solve these problems, which you should work on first. More complicated problems require you to recall facts from several parts of the text and then use one or more of the problem-solving techniques mentioned above. As each major type of problem—synthesis, nomenclature, or structure determination—is introduced in the text, a solution is extensively worked out in this Solutions Manual. 

Over 250 new problems are included in the second edition. The majority of these problems are written at an intermediate level—more advanced than the easier drill problems, but not as complex as the challenge problems. Beginning with Chapter 11, there are additional multi-step synthesis problems that rely on reactions learned in earlier chapters. 

As litis book is a solutions manual, a cummeni on that a.specl of it is al.sn appropriate. The problems in the textbook range from "drill problems, which require you to apply only a single new idea in a repetitive way to several simple cases, to "think" problems, where several ideas, new and old, have to be applied, often to cases which at first glance may look very different from the examples presented in the textbook chapter. This cross-section of problems is intended to illustrate the thought processes involved in analyzing this kind of subject matter, and to resemble the kinds of problems you might encounter in exams. 

Siddeswarappa, B. (2007) Methodology of Taguchi optimization for multi-objective drilling problem to minimize burr size. International Journal of Advanced Manufacturing Technology, 34 1-8. 

WORKED PROBLEM 19.5 Write a mechanism for the equilibration of acetaldehyde and its enol form in acid. This problem may seem mindless, and it certainly has little intellectual content at this point, but it is an important drill problem. Doing this problem is part of reading organic chemistry with a pencil. ... 

PROBLEM 19.47 Write mechanisms for the following acid-and base-catalyzed equilibrations. There is repetition in this drill problem, but being able to do these protot)q al reactions quickly and easily is an essential skill. Be certain you can solve this problem easily before going on to more challenging ones. 

Work aU the problems within each chapter. These are drill problems that you wRl find at the aid of each section that allow you to check whether you have mastered the skills and concepts the particular section is teaching before you go on to the next section. Some of these problems are solved for you in the text. Short answers to some of the othas— those marked with a diamond—are provided at the end of the book. Do not overlook the Problem-Solving Strategies that are also sprinkled throughout the text they provide practical suggestions on the best way to approach important types of problems. 

Figure 4.27 Typical composite drilling problem peelup delamination at entrance. (Kohkonen, K.E., and Potdar, N., in S.T. Peters, ed.. Handbook of Composites, 2nd ed.. Chapman Hall, p. 598, London, 1998)...

Figure 4.28 Typical composite drilling problem pushout delamination at exit. (Abrate, S., in P.K. Mallick, ed Composites Engineering Handbook, Marcel Dekker, New York, 1997, p. 783)...

Formulas and Calculations for Drilling Engineers, by Robello Samuel, ISBN 9780470625996. The most comprehensive coverage of solutions for daily drilling problems ever published. NOW AVAILABLE ... 

Charles J. Conrad and N. Harris McClamroch, The drilling problems A stochastic modeling and control example in Mfg IEEE Trans, on Auto. Control, Vol.AC-32,11(1987), 947-958. 

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