Drill pipe capable of transmitting high-bandwidth data from downhole sensors and surface control signals back to those sensors has been developed and successfully tested. The system incorporates a high-speed data cable that runs the length of each joint and downhole tool. The cable terminates at induction coils that are installed in protecting grooves machined in the secondary torque shoulders of doubleshoulder tool joints at each end of the pipe. The coils are recessed in ferrite troughs that focus the magnetic field. The system is virtually transparent to standard rig procedures and offers robust, reliable operation.The paper provides background data on prior work relating to telemetry drill pipe and contrasts the results of these efforts with the new system. The new system has successfully demonstrated data transmission rates of up to 2,000,000 bits/sec. Current mud pulse telemetry is limited to 8 to 10 bits/sec. Electromagnetic technology provides data rates of up to 100 bits/sec, but suffers from hole depth and formation related electric impedance limitations. Full realization of system benefits requires further development of additional drill stem components with highspeed telemetry capabilities including HWDP, collars, jars and top drive subs. A top drive sub that incorporates the telemetry design has been successfully manufactured and tested and is described in the paper. Development efforts relating to other drill stem components are also detailed. The system has been tested in a laboratory environment and in test wells. Results of these tests along with plans for field-testing in actual drilling environments are presented.Telemetry drill pipe can improve well and field productivity by providing more complete, real-time logging information and reduce drilling time and costs and enhance well control by providing real-time downhole drilling data and early kick detection.

Summary Conventional casing design is based solely on the achievement of adequate design factors in burst, collapse, and tension from the loads generated by the hanging weight of the pipe, internal and external surface pressures, and fluid densities. The effects of cementing, temperature pressures, and fluid densities. The effects of cementing, temperature changes, ballooning, changes in cross-sectional area, bending, and helical buckling are virtually never considered. This paper describes a service-life model for the design analysis of casing strings that include the significant factors that affect the performance of the string. Introduction The service-life model and analysis method is applicable to the design of any casing string but is especially useful for deep, high-pressure wells. Conventional casing design is often inaccurate-too conservative for shallow strings, too liberal for deep strings. Moreover, some of the design factors used currently in the industry can lead to dangerously undersized strings. Because the calculations in the service-life model and in the subsequent triaxial stress analyses are complex, a computer program helps determine a feasible string design. Computer analysis also liberates the designer from the drudgery of repetitious calculations so that he or she can concentrate on achieving a more accurate estimate of service-life conditions. An accurate service-life model that considers the significant variables and a precise analysis method is essential in obtaining an optimum casing-string design. Conventional Design and Analysis Methods The evaluation of a conventional design depends on a comparison between the applied load and the load rating of the pipe. Because most load ratings are based on API equations, I conventional design factors can be referred to as "API load-capacity design factors." Principal and equivalent stress intensities are almost never involved in the evaluation of the design. The applied loads-i.e., the service loads-are calculated from simplistic assumptions based on the hanging weight of the pipe for the tension design, internal and external surface pressures, and fluid densities for the burst and collapse design (Figs. I and 2). In design of a casing string for tension, it is usually assumed that the pipe is suspended in a uniform fluid i.e., buoyancy is considered. Sometimes it is even assumed that the string is hanging free in air-a valid assumption for tubing strings but only in very limited cases. Usually a tension design factor (TDF) of 1.50 to 1.80 is maintained on the joint or pipe-body yield strength. Experience has shown that a minimum TDF of 1.5 is required to avoid string problems with API threaded and coupled (T and C) connections. Thus a 1.60 TDF is often used. On the other hand, flush-joint casing-especially larger sizes (8% in. [21.9 cm] or greater)-requires a higher TDF to avoid joint problems. The effects of temperature changes, Poisson's effect (lateral expansion or contraction of the casing), and changes in the cross-sectional area of the pipe are not normally considered. Nevertheless, these effects can significantly influence the axial load on the casing string. A minimum design factor of 1.00 to 1.33 is usually maintained on the maximum differential burst pressure to which the casing may be subjected in a conventional design. Note that a burst design factor of 1.0 results in an automatic 10% underdesign. Even if the pipe were hydrostatically tested to the API maximum alternative test pressure, at a 1.0 burst design factor the pipe could be pressure, at a 1.0 burst design factor the pipe could be subjected to an in-service pressure greater than the test pressure. It is a principle of pressure-piping systems never pressure. It is a principle of pressure-piping systems never to work the pipe to a pressure higher than the test pressure. Because minimum internal-yield pressure is based pressure. Because minimum internal-yield pressure is based on 87.5 % of nominal wall thickness and the hydrostatic test pressure is equivalent to 80 % of nominal pipe, a 1.094 internal-pressure design factor must be used to avoid working the pipe to a pressure higher than the test pressure. The recent adoption by the API of modified couplings with teflon seal rings has further complicated the selection of an adequate burst design factor. For some sizes, weights, and grades where the coupling partially controls performance properties, the maximum alternative API performance properties, the maximum alternative API hydrostatic test pressure is 80% of the internal-pressure resistance rating. Consequently, as a practical minimum, a burst design factor of 1.25 is required, unless the exact pressure ratings of the casing and connection are known. pressure ratings of the casing and connection are known. Moreover, 1.30 would be preferable and is used by many operators. The effect of axial load on the internal-pressure resistance of the casing is generally not considered. However, it can be very significant. SPEDE P. 141

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractWith water depths increasing to over 10,000 feet, offshore well depths exceeding 34,000 feet and extended reach targets pushing out over 35,000 feet; operators are deepening the setting depths of larger diameter and heavier casing strings. These offshore designs require landing strings with hoisting capacity approaching 2-million pounds. These requirements have exceeded the limits of previous tubular manufacturing and handling capabilities. This paper documents the design, development, manufacture and deployment of a 2-million pound landing string system to meet these requirements. The system incorporates three components: pipe, elevators and slips. The 6 5/8-inch, heavy wall, 150-ksi yield strength pipe incorporates an innovative thick-walled section in the slip contact area for resistance to slip crushing loads and a uniquely designed dual-diameter tool joint to increase elevator capacity. Slips were specially engineered to equalize radial and axial loads, increase the slip-to-pipe contact area, and optimize the contact angle to minimize the crushing loads on the pipe body. Combined with 1,000-ton elevators, the system utilizes conventional rig-up and operating procedures. The design criteria developed for landing string applications and the solutions to the unique manufacturing challenges associated with the heavy wall, high strength pipe are presented. In addition, laboratory and case studies are presented for landing operations, some with axial tension loads approaching 1.75-million pounds.SI to Metric Conversion feet ('): ft. = 3.048 E -01 m inches ("): in. = 2.54 E 00 cm 1,000-pounds per square inch: ksi = 6.894757 E 03 kPa pounds: lb. = 4.448222 E 00 N pounds per foot: ppf = 1.4594 E 01 N/m pounds per square inch: psi = 6.894757 E 00 kPa

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