Automatic Drillers have been used for decades. Most of these systems did a poor job of controlling weight on bit, which resulted in equally poor performance. Thus prompting two questions: "What is required to achieve a much better level of control of drilling parameters like weight on bit?" and "What field performance results do we see from improved control?" This paper will address these questions by examining the development and field performance of an advanced automatic drilling system. It will show how the entire system, not just the mechanics or the software, needs to be designed from a control system point of view. It will present the results of field usage of the system, and demonstrating the performance benefits resulting from improved control. Finally, it will suggest future developments for this type of advanced product. Introduction Attempts to develop Automatic Drilling controls for earth boring rigs started before the turn of the century. They were generally described as Drilling Feed Controls. Over the years many different designs were tried with limited success and the driller-operated "brake handle" feed system continued to be the preferred method. The efficiency of an automatic feed control was never denied. However, implementation proved to be illusive. With the recent advent of microprocessors and the development of proportional brake controls, the limitations experienced in the past no longer seemed insurmountable. In 1997 Helmerich and Payne approached Varco International with the challenge of developing an "electronic" feed control system. The first effort, installed on six H&P land rigs, referred to as the "six pac rigs" proved very successful. Significant improvements in drilling efficiency were recorded. Although the initial results exceeded expectations, further development of the control algorithms have greatly reduced the original design's dependency on operator's expertise. At the same time, development of improved control components resulted in another step improvement to drilling efficiency. Today's systems are highly automatic, adapting themselves to different methods of control including weight on bit (WOB), fixed rates of penetration (ROP), constant pressure (?P), and constant torque. This paper describes the evolution of this modern day design, referred to as an "Electronic Driller" and the field performance of various design irritations. History Of Feed Control Brantly in his book on History of Oil Well Drilling1, devoted a whole chapter to Drilling Feed Controls. A French mining engineer, Rololphe Leschot, developed the first "automatic" means employed for controlling bit feed-off into the formation in the early 1860's. The application was a diamond core drill used to drill blast holes for a tunneling project. Leschot used a simple hydraulic cylinder feed with a constant pressure to produce constant force on the bit. Over the subsequent years, numerous methods were tried, many of them quite novel in approach. Examples include so-called torque-based machines built by National Supply Company and Oil Well Supply Company. In the 1930's hydraulic feed rotary tables of various designs were applied. These hydraulic feed machines used cylinders that operated similar to Leschot's original design. By the 1940's most feed control machines became band brake control machines as brake performance improved. Most of these devices were pneumatically actuated and used inputs from the rig's standard weight indicating instruments. They were connected to the manual brake handle and controlled the feed by keeping the string weight constant.

This paper presents the technical advances made in the use of power swivels in replacing the rotary table. The equipment, drilling techniques and accelerated drilling time are reported. Specifically, special features of the use of a power swivel are also presented, i.e., drill up, remote pipe stabs, safety, presented, i.e., drill up, remote pipe stabs, safety, operating cost reduction, drilling down 90 ft. stands. The object of this report is to acquaint people with the recent advances in the use of the power swivel. Introduction A new electric power swivel drilling system has been developed and successfully placed in operation on two SEDCO jackup drilling rigscurrently drilling for Abu Dhabi Marine Operating Company (ADMA-OPCO). The swivel, called a Top Drive Drilling System, consists of a 1000 HP electric DC traction motor and an innovativepipe-handling system developed by Varco Oil Tools. The concept of rotating pipe directly with a motor connected to the top of the drill string, in contrast to a kelly sliding through a rotary table, is not a new one; it is commonly used on workover rigs that do not have rotary tables. A However, power swivels, as they are often called, have not been used extensively for drilling due to pipe handling compromises and the poor performance of previous designs. The Top Drive System described in this paper represents a significant step forward in the practical application of the basic concept. Its development and subsequent field use has been highly successful. Two significant improvements attributable to the new system are excellent reliability and very efficient pipe handling. Both factors are enhancing the operation of the rigs on which they are installed to a degree that both rigs have reduced overall drilling time 20%on the average well. Figure 1 illustrates the power swivel and pipe handling systems. HISTORY OF POWER SWIVELS The offshore use of power swivels and power subsstarted in the early 1950's. A Baash Rosshydraulic drive power sub unit was utilized offshore on the drill ship NOLA I. This was followed by a power swivel used on the dynamically stationed coring vessel EUREKA in the early 1960's. Several other hydraulic drive power subs and swivels were used for special applications, i.e. the GLOMAR CHALLENGER deep sea coring project. One of the first fully electric driven power swivels was a unit built and tested by ARCO for high RPM drilling tests. Brown Oil Tool and Bowen developed and marketed the first electric drive power swivels in the early 1970's.The VARCO power swivel system went into use in 1982. History has proven that a power swivel is a tool which provides good economical returns. It drills hole faster and eliminates several drill problems. The power swivel, when used in conjunction with a handling system, gives even more advantages. III SYSTEM DESCRIPTION A. Design Philosophies The factor overriding all others in the design of any power swivel is reliability. Rotary tables, kellys and kelly drive bushings have an inherent reliability as a result of many years of experience. Almost all drilling personnel are well-schooled in their use, care and maintenance. Hence, their perceived reliability is very high. On the other hand, power swivels have had only limited use. Consequently, they will not have aperceived reliability unless they can function continuously without failure and experience only minor repairs. Anything less will be interpreted by most operators as poor reliability regardless of overall performance, and most would not risk power swivel use. The power swivel's reliability can be broken down between two areas for analysis and discussion. P. 359

Summary Rig automation projects can benefit from the experiences developed during the successful automation of rig pipe-handling equipment. The data provided were derived from the operation and development of iron roughnecks and pipe-handling systems in the field. This paper includes a study of failure mechanisms and how they affect reliability, presents maintenance experiences to show the impact of automation on crew capability and training, and describes many operational and design pitfalls. Introduction Four years ago, Varco Intl. Inc. installed fully integrated, automated pipe-handling machines (PHM's) on two jackup rigs and one semisubmersible rig. The PHM unit on the semisubmersible was removed in 1989 primarily because the operator was not satisfied with its reliability. The PHM's on the jackups operate in the North Sea and have undergone extensive modifications as a result of the information learned during their operation. These modifications include major changes to the control hardware, hydraulic systems, and many of the control components. Many of the changes resulted from activities and operations not anticipated during the original design of the system. Today, these two PHM's are considered successful state-of-the-art automated pipe-handling systems, and seven additional units have been ordered. One of these new units is operational and two more have been installed. The PHM's trip drillpipe and drill collars up to 9% in. [248 mm] in diameter without floor hands or a derrickman. PHM Description The PHM trips drillpipe and drill collar stands in and out of the well by remote control. This machine has spinning, torquing, lifting, and rack stand positioning. Each stand has fingerboard locking. Many operations, such as stand makeup and breakout, are performed automatically. The PHM (Fig. 1) consists of a column assembly that runs from the drill floor to the racking board, upon which two extending arms and an iron roughneck assembly are mounted. The columns move between well center and setback and can rotate 90° to the left or right. The arms are pivot-mounted and mechanically interconnected to operate in parallel. Hydraulic clamping jaws at the ends of the arms hold drillpipe and drill collars from 3½ to 9 ¾ in. [88.9 to 248 mm] in diameter.

This paper was presented althe 9th Annual OTC in Housfon, Tex., May 2-5.1977. Tfiematerial is subjeclto correction by the ilutllor. Permission to copy is restricted to an'abstract of not more than 300 words. ABSTRACTIn offshore construction work related, to platforms, one of the difficult operations has been the connection of add-on sections to pin piles as they are driven into the sea floor. The reason for this difficulty has been the relative motion of the derrick barge and the fixed platform. This paper describes the design of and the application of a pile aligning system that makes this operation much easier to accomplish. It emphasizes the design of the system and its field operation conducted in the Gulf of Mexico. It descri bes the des i gn con,cepts, the actual hardware used to implement xhese concepts, and the successful operation of this hardware on the actual job site.

Top-drive drilling has become one of the new technologies of the 1980's. Application of this seemingly old concept is now widespread in most offshore areas of the world. Top-drive drilling may be one of the biggest changes made to the rotary-drilling method since the development of the rotary table.This paper analyzes why the concept of drilling with top drive, similar to the very old concept of a power swivel, has suddenly become so successful. Applications and locations are presented to show the system's worldwide use. Results of more than 50 systems currently in operation are analyzed to present benefits and trends.The results show surprising benefits for almost any type of well, and overall time savings generally exceed 20%. Benefits from the extended-reach potential associated with top drives are enormous. These results explain the primary motivation for most applications of the system. Recent Top-Drive DevelopmentsDrilling with a rotary table requires a host of auxiliary equipment not normally identified with the drilling process, as well as those items obvious to the method. Those components normally associated with rotary-table drilling are the kelly, the kelly bushing, the swivel, and the rotary table. Components that are not frequently thought to be significant make the difference between operational efficiency and difficult, if not impossible, alternatives.