This is a study of numerical control, its application, and the design of a numerical control program for a drilling machine. The study sought to obtain information on the function of numerical control; the different types of numerical control used by industry; and, the advantages of using numerical control.

Mud pumps used on offshore installations for drilling operations have been known to experience unpredictable breakdowns, including during critical stages of drilling. The fluid end has been identified as requiring more maintenance work due to component failure, compared to the power end. The most common maintenance strategies in use include breakdown maintenance, time-based maintenance and condition monitoring. Time-based maintenance, based on running hours, is the most commonly preferred method by most, if not all, mud pump operators. However, the nature of drilling operations require pump performance with variable loads (pressures), variable speed characteristics and time-based maintenance would not be able to account for the different operating conditions within any identical time frames. To address this shortcoming, this research looked at the postulation that material wear loss is related to the energy expended and developed a dedicated reciprocating wear test system to identify and investigate the effect of operating variables on the wear loss of piston rubbers, which was considered to be the most problematic of the fluid end components.

Cutting operations are important and commonly used operations in the field of manufacturing. Automated machining is today commonly used in CNC-machines. One common drawback with automated machining is that the tool condition is challenging to predict which leads to a conservative tool replacement times. This leads to a low utilisation of the tool economical lifetime and an unnecessary high number of tool replacements. Methods for indirect continuous monitoring of the tool wear exist but usually require retrofitting of external sensors that can be both costly and also interrupt the machine operation due to the additional wiring. It is therefore of interest to investigate the possibility to use the, often high resolution, sensors already fitted in a CNC-machine to extract valuable data that can indirectly give an estimation of the tool condition. This thesis work has, with attention to the X-, Y- and Z-position sensors, resulted in development of algorithms that show relations between tool wear and data acquired from these sensors. The algorithms operate in the frequency domain to determine changes in the dynamic response over the time of tool degradation.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Hiroshi Iwasaki. / M.S.

No description available.

This thesis presents a detailed analysis of the plane rake faced drill design, its grinding method and grinding wheel geometry. A fundamental geometrical analysis has then been carried out on the major cutting edges of the modified drills according to the national and international standards. It has been shown that this new drill design results in a significant increase in the normal rake angle at lips as well as point relieving at the chisel edge region. Geometrical models for the various drill point features have been established which uniquely define the drill point features of the modified drill design. A comprehensive experimental investigation has been carried out to study the drilling performance of the modified drills, when drilling a high tensile steel, ASSAB 4340, with TiN coated high speed steel drills over a wide range of drilling conditions. Comparing to the drilling performance with conventional twist drills under the corresponding conditions, it has been found that the modified drills can reduce the thrust force by as much as 46.9% with the average of 23.8%; the reduction of drilling torque is also significant at an average of 13.2% and the maximum of 24.9%. Similarly, the new drill design shows great superiorities over the conventional drills in terms of drill-life. In the drill-life tests, a few conventional drills were broken, but all plane rake faced drills performed very well. In order to estimate the cutting performance in process planning on a mathematical and quantitative basis when drilling with the modified drills, predictive cutting force models have been developed based on the unified-generalized mechanics of cutting approach. The models have been assessed qualitatively and quantitatively and showed good agreements with the experimental thrust, torque and power. Empirical-type force equations have also been developed to provide simple alternatives for practical applications.

Thesis (M.S.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1982. / Includes bibliographical references (leaves 151-153).

Thesis (M. Sc.)--University of Hong Kong, 2002.

The system studied in this thesis is called the Low Rise Return system and uses a partly filled marine drilling riser with a variable mud level which is used control the bottom holes pressure.Initially main components of the Low Riser Return System are listed and explained. Then the performance characteristics of the system are explored. Level movements in riser during level increase and decrease at constant mud pump rates are explained along with the effect of mud pump rate on maximum level increase and decrease rates.A simple simulator is then presented that calculates the bottom hole pressure when pump rates are changed. The simulator includes a function that enables it to simulate lost circulation scenarios.The simulator is used to simulate some preferred scenarios. First a pressure increase and decrease at constant mud pump rates are simulated. Then it is shown how a faster pressure decrease can be achieved by temporarily lowering the mud pump rate. Next simulations are shown where changes in mud level are used to compensate for changes in equivalent circulation density as mud pump rates are changed. Finally simulations are run that demonstrate how mud level can be reduced to cure lost circulation scenarios. Results and lessons learned are then discussed.

In 2006 the Petroleum Safety Authority Norway (PSA) performed a well integrity survey. The survey indicated that about 20 % of wells on the Norwegian Continental shelf (NCS) may suffer from well integrity issues. Most of the problems were related to deficiency in annulus safety valve, tubing, cement and casing. Pressure build-up in annulus, i.e. sustained casing pressure, is one of the main indicators of a significant well integrity problem. Increased understanding on the field may help engineers to design wells with better integrity in the future. This thesis describes SCP and its most common causes with emphasis on the relation between casing shoe setting depth and the occurrence of SCP. Primary and secondary barrier is described together with the common practice of choosing casing shoe depth. Formation strength and its impact on setting depth is explained together with a brief introduction of the different formation integrity tests. Generic cases have been studied to determine the relation between unfavorable casing shoe setting depth and the occurrence of SCP. For each case there is a suggestion as how the well may be redesigned so that the risk of SCP is reduced. Information on the theme has been acquired through studying and comparing different papers, booklets, previous reports and reviews concerning the subject. The Norsok standard D-010 and 117 – OLF recommended guidelines for well integrity have also been very informative during the study. To be able to avoid SCP and at the same time improve well design, it is important to properly understand how SCP arises. Changing the casing shoe setting depth to a more suited depth or formation cannot alone eliminate SCP. To eliminate SCP a good conversion between Top of Cement (TOC) and setting depth of the previous casing shoe is required. The best way of avoiding SCP because of casing shoe setting depth is to make a thorough investigation of the underground and carefully choose the setting depth.