Retractable Bits Development and Application

Gelfgat, Mikhail; Alikin, Rudolf

doi:10.1115/1.2795022

Cited by 4 publications

(2 citation statements)

References 3 publications

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“…This work was stimulated by a desire to reduce the time spent tripping to replace bits that had relatively short runs. 2,3 In the late 1960s, the first broad effort to develop all the surface and downhole components needed to drill with casing and retrievable bits was done by the Brown Oil Tools Company. 4 This "casing-drilling system" included components for rotating the casing with an electric top drive, gripping the casing without utilizing its threads, locking a wireline retrievable drilling assembly to the bottom of the casing, and using an underreamer to enlarge the borehole.…”

Section: Casing While Drillingmentioning

confidence: 99%

Applying Risk Analysis to Casing While Drilling

Houtchens¹,

Warren²,

Tessari³

et al. 2007

Proceedings of SPE/IADC Drilling Conference

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TX 75083-3836 U.S.A., fax 1.972.952.9435. AbstractEngineers and managers make decisions related to drilling operations every day that must balance the risk of various alternatives. These decisions may be based on a mental, experienced based risk model that has been developed over years of decision making. However, many companies are moving to explicit risk models where risk and its economic impact are quantified. Risk is composed of two components: the probability of an event occurring and the economic consequences if it occurs. This modeling uses a logical progression to predict economic impact of trouble events such as well control, loss of circulation and sticking of the drill string or casing string. Applying a risk model to new technology is difficult because there is no experience base for quantifying either the probability of an event occurring or the consequences of the event. This is particularly true when the technology has operational components that go against normal practices. Such is true with Casing while Drilling. Casing is used as the drill string to solve problems that one would normally expect to be made worse by drilling with a smaller wellbore clearance, higher annular velocity, and little ability to make conditioning trips. This paper will show the results of more than 280 wells and over two million feet of hole drilled with casing over the last eight years. Comparisons will be made to conventional drilling methods in several of the areas where the technology has been applied. Elements of study include casing fatigue, casing wear, tool reliability, underreamer durability and reliability, differential sticking, lost circulation induced by increased ECD, acceptable penetration rates, etc. Results of these wells in difficult drilling areas show positively that drilling with casing is more efficient and encounters less trouble time than conventional drilling, saving operators both time and money. These savings can be seen in daily operating costs, personnel safety and in insurance premiums for the operators and drilling contractors.

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Section: Casing While Drillingmentioning

confidence: 99%

Applying Risk Analysis to Casing While Drilling

Houtchens¹,

Warren²,

Tessari³

et al. 2007

Proceedings of SPE/IADC Drilling Conference

View full text Add to dashboard Cite

show abstract

“…This work was stimulated by the desire to reduce the time spent tripping to replace bits that had relatively short runs. 11,12 Work done by Brown Oil Tools 13 in the late 1960's was the first broad effort to develop all the surface and downhole components needed to drill with casing and retrievable bits. This "casing-drilling system" included components for 1) rotating the casing with an electric top drive, 2) gripping the casing without utilizing its threads, 3) locking a wireline retrievable drilling assembly to the bottom of the casing, and 4) using an underreamer to enlarge the borehole.…”

Section: Introductionmentioning

confidence: 99%

Drilling with Casing Reduces Cost and Risk

Warren¹,

Houtchens²,

Tessari³

2006

Proceedings of SPE Russian Oil and Gas Technical Conference and Exhibition

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Drilling with Casing Reduces Cost and Risk

Warren¹,

Houtchens²,

Tessari³

2006

All Days

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More than 1.2 million ft of hole has been drilled in over 260 wells with retrievable casing-while-drilling tools. These wells have been drilled with seven casing sizes ranging from 4–1/2″ to 13–3/8″. The drilling system is composed of downhole and surface components that provide the ability to use normal oil field casing as the drillstring so that the well is simultaneously drilled and cased. The casing is rotated from the surface for most operations. The experience gained while drilling these wells has led to a better understanding of the advantages of the process. It's most effective applications have been to reduce the cost and risks associated with wells which routinely experience lost circulation when drilled conventionally; wells in which well control is difficult for tripping drillpipe; wells where excessive fluid loss into low pressure reservoirs impairs the production and ultimate recovery; and wells where it is difficult to get the casing shoe as deep as needed. Introduction Simultaneously drilling and casing a well by using conventional oilfield casing as the drillstring has been a dream of a few drillers since the rotary drilling process was introduced in the late 1800's. One patent1 dating back to 1890 describes a rotary drilling process for simultaneously drilling with the casing (including a sand control screen) and then retrieving the hydraulically expandable bit. Another patent issued in 1926 list the advantages (Table 1) of drilling with casing with a retrievable bit.2 Inventors kept up a steady stream of ideas aimed at fielding a practical system for drilling with casing and a retrievable bit.3–10 Considerable work was done in Russia beginning in the late 1930's to develop a system for replacing the drill bit without having to trip the drillstring. This work was stimulated by the desire to reduce the time spent tripping to replace bits that had relatively short runs.11, 12 Work done by Brown Oil Tools13 in the late 1960's was the first broad effort to develop all the surface and downhole components needed to drill with casing and retrievable bits. This "casing-drilling system" included components forrotating the casing with an electric top drive,gripping the casing without utilizing its threads,locking a wireline retrievable drilling assembly to the bottom of the casing, andusing an underreamer to enlarge the borehole. Ultimately, this work failed because of the inertia in the drilling industry, but it did stimulate the development and commercialization of the top drive. Tesco started development of a casing-while-drilling (CwD) system in 1997 that included the complete system needed to drill with casing. While others had failed to accomplish this earlier, improvements in materials (e.g. PDC cutters for underreamers), increased market applications (particularly related to problems encountered in drilling marginal fields), and the brute determination and financial commitment of Tesco management successfully produced a CwD system that has gained commercial acceptance. This system has proven to be a practical method of solving drilling problems and of reducing drilling costs.14–18 It is currently being used in both onshore applications where entire wells are drilled with casing and offshore applications where specific hole sections are drilled with casing.

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Retractable Bits Development and Application

Cited by 4 publications

References 3 publications

Applying Risk Analysis to Casing While Drilling

Applying Risk Analysis to Casing While Drilling

Drilling with Casing Reduces Cost and Risk

Drilling with Casing Reduces Cost and Risk

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