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To achieve safety, high quality, and efficiency in deep drilling, it is necessary to get formation drillability around the borehole during drilling-trajectory planning and intelligent drilling control. Since the drilling data have the characteristics of low value density and noise in the process of deep drilling, it is difficult to model formation drillability in deep drilling. In this paper, a new online modeling method for formation drillability based on online sequential nadaboost extreme learning machine (OS-Nadaboost-ELM) algorithm has been proposed. Firstly, the well logging parameters are chosen as the inputs of the model, whose output is formation drillability. Then, several ELM models are established and the outputs of these models are as weak learners. Then the weak learners are combined by Nadaboost algorithm in order to get a strong learner. Finally, the recursive least squares algorithm is used to adjust the model. The numerical test results show that, in both prediction accuracy and training efficiency aspects, the proposed method is better than other prediction methods such as multiple regression, gray method, back-propagation neural networks, Nadaboost extreme learning machine and online sequential extreme learning machine. Thus the prediction model serves as the online geological model to develop intelligent drilling systems.

Round trip activity occurs discretely due to the abrasion of drill bit in the deep drilling project. Round trip has great impact on the drilling performance because it takes more time to change a drill bit as the depth goes deeper. Therefore, a reliable prediction technology of the round trip should be secured for feasibility analysis and effective management of the drilling project. Lee et al. (2013) developed the TOSA (round trip occurrence simulation algorithm) which can analyze the depth and timing of round trip occurrence at each abrasion state of bit. However, TOSA has weakness that it takes long time for simulation because the number of simulation increase exponentially as increasing the number of simulation section. This study developed the TOSA based round trip performance prediction module using genetic algorithm for simulating in a short time and verified simulation results.

The paper presents an optimization by using the robust engineering approach, for the optimization of the deep drilling process by assessing the surface roughness by the Ra parameter. The trials were developed according with the Robust Engineering principles, by applying the Taguchi Method. The parameter for decision is the average profile height (Ra) of the roughness. Finally, there are presented solutions for the setting-up the deep drilling parameters levels in such a way to assure the best quality at the level of the generated surface. The method results to be reliable for being applied for achieving the optimal setup machining parameters used for the deep drilling process.

The demand for superhigh-precision austenitic fuel rods for fast-reactor piles increases every year. Accordingly, means of reducing the product cost without loss of quality—in particular, resistance to radiative swelling—are required. Optimization of the production process calls for the introduction of helical broaching and radial forging instead of deep drilling, with the necessary auxiliary processes.

Worldwide, many research groups have been dealing with several innovative drilling technologies. Their common aim is to significantly decrease the overall price of the drilling process, particularly to keep the high constant speed, energy efficiency and shorter drilling time. The vision of geothermal energy, as the clean energy of the future, is currently one of the most driving challenge for development of new deep-drilling technologies. This paper presents one of such activities — development of novel technology based on electrical plasma for hard rock drilling. During this development, another application was identified as well — milling of steel casing and cement for well plug & abandonment operations.

According to the characteristics of wire-line coring drilling technology and combined the project of ZK3 borehole in salt exploration in Ye-wu sag in Henan province, the data of construction cost and efficiency for wire-line coring and roundtrip coring separately have been analyzed. In a certain evaluation period, the technical and economic evaluation for wire-line coring and simulation roundtrip coring in ZK3 borehole conducted by net present value (NPV) method, the result shows that, in ZK3 borehole, comparing with roundtrip coring, the drilling efficiency of wire-line coring method improved by 85%, the profit is 6.3 times than roundtrip coring, its technical economy is more obvious along with the depth increase. The sensibility analysis shows, the most sensitivity factors effecting on the borehole efficiency are construction price and construction period.

The aluminum alloy drill rod has light weight, high specific strength, more deep drilling depth and so on. The development and application of aluminum alloy drill rod has a great practical significance for improving geological drilling efficiency at where it is hard to enter and promoting scientific drilling technological progress and reducing the energy consumption. In this paper, the current situation and key technology of batch and serialization for aluminum alloy rod were introduced, and its application technology characteristics, trial production key technology, indoor experiment, and application situation had been analyzed. The research about aluminum alloy rod for high temperature was suggested after reviewing the foreign research results.

Over the past years, deep drilling technology developed quickly. New technologies better quality of drilling work and accelerated the drilling process. At present, 20-25% are new techniques while 75-80% drilling methods used worldwide are traditional. Slovakia is quite at the rear of this tendency: our utilization ration shows 95-98% traditional drilling methods, in comparison to only 2-5% new ones. Advancement of new deep well boring technologies causes the evolution of new types of drilling sets for deep drilling (depending on applied techniques). Techniques used have a mechanical and physical impact for drilling of rock. Several tests and analyses of disintegration and drilling methods were performed over the last years. The article focuses on a description of the working principle and utilization possibilities.

Drum-shaped stone tongue that there are 3 ~ 5 m thick wedge silt on the bottom formed in the junction of silt and the stone embankment by reclamation silt with mountain stone during the course of backfill. In the paper, on the basis of drills, superficia drilling holes, deep drilling holes and vibrating stop plank model, boundary stone embankment shape and soft soil layer depth were obtained, cross section of stone embankment and stone embankment boundary were revealed during the course of artificial fill, study the stone tongue shape, soft soil around stone tongue, silt characters on stone tongue bottom and reinforcement treatments were studied to obtain treatment method which can satisfy the engineering requirement and can save the engineering cost and provide mature construction technology and method for the similar subgrade treatment of sea reclamation engineering.

Continuous development of science and technology, the human ability to conquer nature and continuously improve, but also rapid growth in social demands, significantly reduced the amount of available resources. Earth-shallow layer drying up of resources of our human life, forcing people to the underground exploration of the deeper substance to meet human needs. This requires adaptation of deep drilling tool for drilling needs good equipment, deep-hole wireline coring drilling equipment in adapting to constantly update and be perfect with this demand.

Because the hard strata and big angle of bedding, deep wells in Daqing Xujiaweizi area well deviate easily. Low efficiency and long drilling cycle are big problems of drilling engineering since small bit weight is used to avoid well deviation. To improve efficiency, Smooth drill collars with high bit weight WOB technology is used in the deep wells in Daqing Xujiaweizi area. Facts prove that penetration rate can be increased more than 20% , bit life can be extended more than 30% and well deviation can be corrected in Daqing Xujiaweizi deep drilling. This paper through analyzes the mechanism of smooth drill collars BHA ,then build kinematic model and dynamic mode,so bit side force's Solution formula is worked out,Get the principles and applicability of smooth drill collars with high bit weight WOB technology.

Moving into the next decade, wells in the Middle East are becoming more challenging as the deeper and more complex plays are exploited. This environment will be challenging from a torsional and tensile loading standpoint, and will be dynamically very active. This type of environment combined with high levels of H2S calls for a new high grade of sour service pipe. The Middle East is also opening up to the idea of high speed telemetry and wired pipe economics that call for a long lasting pipe product. When using sour service pipe that is traditionally limited to 105 KSI grades, even with an optimized string design, drillers sometimes have no other option than to sacrifice the margin of overpull, risking losing the well if fishing is unsuccessful. Alternatively, they can elect to use drill pipe, which is not suited for use in this corrosive environment, generally using API S135, with a risk of parting the string due to H2S embrittlement. To address these operational limitations, the pipe body, which is the drill pipe limiting member in tension, has to come with higher material strength and at the same time exhibit improved Sulfide Stress Cracking (SSC) resistance compared to API S135 grade. A novel grade of drill pipe was developed over a period of two years that is the strongest sour service drill pipe the industry has to offer to date and gives drillers an extra 19% of tensile capacity with its 125 KSI material yield strength. This new grade has been ordered for use in various regions of the world and for numerous applications. At this time, it is being used for intervention and stimulation operations in the Gulf of Mexico (GOM), and drilling long, extended reach (ER) wells with wired telemetry drill pipe in the Middle East. This paper presents the phases of the grade development and discusses testing requirements for the crossover between strength and SSC resistance. It also includes statistical data on the first full scale manufacturing tests. Finally, it outlines the products expectations for field applications.

Deep hole machining accuracy plays a crucial role in product’s quality. The results of an investigation into the machining accuracy of deep drilling holes which highlights problems of bore diameter enlargement magnitude assessment are presented in this paper. Through the study of BTA deep drilling tool properties and mechanism, as well as the formation rule of deep hole surface, clarified the burnishing mechanism of guide pad in deep hole drilling, and obtained the directly relationship between surface formation rule and the guide pad. After drilling experimentrevealed the effect of guide pad on bore diameter enlargement magnitude.

Rotary drilling rigs, general construction equipment, are widely used for deep drilling of ground for the foundations of public works. A new 250kN.m-type rotary drilling rig, most widely used in this field, is under development, and this study focuses on the operational safety of the mast subassembly on the basis of structure analysis of the mast subassembly using a finite element method with ANSYS. When using a drilling rig, an electric rotary drive supplies power for drilling. Here, the elevation of the rotary drive along the mast needs to be changed according to the geological construction environment. Through the analysis, the allowable torques at various elevations of the rotary drive are evaluated, also the safety of the drilling tool called the kelly bar subassembly is examined. Finally, the suitability of the mast subassembly design is examined from the analysis results.

The blowout accident is a major accident in the petroleum drilling system which may lead to extremely severe consequences. We can avoid a blowout by the use of effective early kick judgment method to detect the kick timely while the kick is a harbinger of the blowout. This paper describes the methods commonly used in the early kick monitoring, and proposes a method based on the Ultrasonic Doppler Effect used in early kick detection. The effectiveness of this method used in the deep drilling liquid is demonstrated.

In high aspect ratio micro deep drilling, to shorten the machining time while maintaining the tool life, the addition of ultrasonic vibrations to increase the step feed was examined. First, machining experiments with L/D=10 were conducted, and an increase in the step feed upon the addition of ultrasonic vibrations was confirmed by evaluation of the cutting force and tool wear. Furthermore, micro deep drilling with a high aspect ratio of L/D=20 was examined. Our results reveal that reducing the cutting speed and adding ultrasonic vibrations shorten the machining time by increasing the step feed while maintaining a long tool life. Moreover, we confirmed that the developed technique is effective for the micro deep drilling of holes with a small diameter of 0.1 mm and L/D=15.

This paper presents an experimental study of the positive effects of vibration-assisted deep drilling of aluminum alloy Al-6061. The four most important evaluation criteria in drilling&mdash, machinability, workpiece temperature, torque, and material removal rate&mdash, were chosen to be investigated. Holes with a depth-to-diameter ratio of 13 were drilled by high speed steel (HSS) twist drill bits of 3 mm diameter, using both methods of conventional drilling (CD) and ultrasonic-assisted drilling (UAD). Three levels of axial force of 6 kgf, 9 kgf, and 12 kgf were kept constant for each pair of comparison experiments. It was found that workpiece temperature and torque not only changed from one drill to the other, but were also dependent on the hole depth being drilled. Comparisons were made in-pair between CD and UAD under the same axial force and at the same order of hole numbers. The result shows that the material removal rate with UAD was up to 3.5 times higher than that with CD and the average workpiece temperature and torque in UAD were reduced by 3.5 and 6 times, respectively. Moreover, tool life in UAD was observed to increase from 2.5 to 5 times, in terms of number of holes drilled, compared to that in CD.

This paper highlights the development of micro long flat drills with nominal diameter and flute length of 20 μm and 200 μm, respectively, by precision grinding. Furthermore, it also covers the evaluation of the developed micro long flat drill in micro deep drilling. Micro long flat drills were made of ultra-fine grained cemented carbide containing WC particles with an average particle diameter of 90 nm. First, the study focused on establishing the optimal web thickness of micro long flat drill showing the best performance in micro deep drilling. In drilling experiment, observation was conducted with the aim of finding the best conditions and method of micro deep drilling into both duralumin and stainless steel workpieces. This observation included the applications of ultrasonic vibration (USV) and step feeding method. The study proved that there was an optimum web thickness resulting in the best drilling performance. Furthermore, the application of USV during drilling could lead to a longer tool life significantly. However, there was no improvement of drilling performance in drilling with step feeding.

Gundrill boring operations are sometimes used to obtain holes with high surface quality and accuracy requirements, impossible to fulfill using core drilling techniques. This article presents a feasibility study concerning the use of vibration drilling technique for gundrill boring operations, in order to ease the chip extraction by periodical breaking. Mathematical models defining a methodology used in order to compute and/or choose system parameters are presented. Rubbing effect is discussed and its influence is proved to be much smaller than for core drilling. Experimental results presented validated mathematical models and give hopes for a possible industrialisation.

The forging process plays an important role in the automotive industry thanks to the good mechanical properties of the forged parts. Nowadays, due to the European policy of increasing efficiency in raw material and energy usage, the metal forming sector is demanding new innovative technologies. In this context, rotary extrusion technology is a very promising metal forming alternative to the drilling techniques after forging processes.The presented work is focused on hollow shafts that are usually manufactured using a combination of forming and metal cutting techniques. Deep drilling is the most common technique to obtain internal holes in the automotive hollow parts, but it is an expensive process in terms of material usage. In this framework, rotary extrusion appears as an alternative technology that leads to the reduction of material usage and process time. The tubular shape is formed with the combination of two forming processes: flow forming and backward extrusion.This paper presents the development of a simulation methodology, the process design for a hollow part, the specifications of the experimental unit, and the manufactured prototypes in order to validate the simulation model. Also the incremental process is improved thanks to a sensitivity study of the rollers geometry. Rotary extrusion experiments are done using a modified flow forming machine and 20% material saving is achieved when obtaining the deep hole in comparison to the current deep drilling technology. The process design and numerical model tasks carried out try to provide the industry manufacturers an alternative technology to drilled parts considering the advantages of rotary extrusion parts.

Axial deviation of holes is a serious problem in deep drilling operation. As the results, the control system for axial deviation of holes in deep drilling was developed. The guide-pad on the new drilling tool head, the control pad, slightly moves up and down by piezo actuator in radial direction with each tool revolution. The axial deviation of the tool head is measured by in-process sensing system with laser and corner cub prism. This paper presents the development of the control method of pad using piezo actuator and the axial deviation mechanism by control pad is clarified. And it is verified various factors for deviation ability.

Investigations on electrical conductivity of biotite gneisses and garnet amphibolites from the KTB borehole (3500–3800 m) were carried out in two laboratories under different physical conditions. Gneisses exhibited higher anisotropy of electrical conductivity than amphibolites. The explanation of the observed anisotropy of electrical conductivity can be found mainly in the structural features (in particular, the foliation fabric) of these rocks. The results indicate the persistence of anisotropy of electrical conductivity to high temperatures (at least 1000°C).

Archaic ideas that women in tunnels lead to misfortune have resulted in the fact that until only recently no women were employed for tunnel construction work. The only woman who was welcomed is Saint Barbara. But in this paper I consider the construction sites of the tunnels not only as a space of miners and engineers working underground, but on life around the tunnel, when and where women come into view. The first tunnel through the Gotthard was built between 1872 and 1882. Today, the Gotthard region is being reconfigured through the tunnel construction sites of the New Rail Link through the Alps (NRLA). During the construction of the historical tunnel, the population of Goschenen in the North and Airolo in the South grew rapidly. Most of those who settled at the tunnel construction sites came from Italy; women were clearly in minority as all required lodgings and food. The division of labor showed gender-specific patterns that were strongly shaped also by family relationship patterns. Because the population of the provisional tunnel construction villages was interconnected both socially and economically, the majority of the men and women followed the construction sites as families or as groups of relatives. In this way, living and working in mutual exchange shaped the complex structure of this micro society. At the same time, the large number of incoming people created fear in the established village. Relations between the local community, now in the minority, and the temporary residents were marked by mistrust. Despite similarities, life at the tunnel construction sites of the Gotthard is very different today. Still only very few women work as engineers and none as miners. Because migrating in family groups has become rare, the tunnel spaces even more separated: the underground world of the men in the tunnel and the world above ground of the women at home.

Ultra-deep drilling, below about 20,000 ft (6,096 m), is extremely expensive and limits the recovery of hydrocarbons at these depths. Unfortunately, rock breakage and cuttings removal under these conditions is not understood. To better understand and thus reduce cost at these conditions an ultra-deep single cutter drilling simulator (UDS) capable of drill cutter and mud tests to sustained pressure and temperature of 30,000 psi (207 MPa) and 482 °F (250 °C), respectively, was designed and manufactured at TerraTek, a Schlumberger company, in cooperation with the Department of Energy’s National Energy Technology Laboratory. UDS testing under ultra-deep drilling conditions offers an economical alternative to high day rates and can prove or disprove the viability of a particular drilling technique or fluid to provide opportunity for future domestic energy needs.

It is well known that the upper ball joint in a marine riser, in deep drilling, can cause fatigue damage in the drill pipe passing through it. A study of fracture mechanics and S–N curve approaches has been undertaken to determine the dynamic fatigue damage in the drill pipe. Miner’s rule is utilized in both methods to determine the total damage. The results of both methods are compared.

Preliminary studies indicate that shallow magma bodies may be successfully tapped and their heat energies converted into electricity. Based on these studies, we develop a model for the potential cost of magma-generated power.

This paper presents and discusses the current state of developments in harnessing geothermal power for medium and large-scale generation of electricity and for space heating worldwide. Potential and current developments and probable and possible developments both in developed and developing countries in near future and long term are reviewed. Topics discussed include enhanced power cycles for enhancing geothermal sustainability, deep drilling projects in Iceland - exploration of deep unconventional geothermal resources, the phases of development of a 400 MWe generation capacity geothermal scheme in NE Iceland, geothermal development in reducing CO2 emissions, and perspectives on the future of geothermal energy in the United States. Technology of harnessing geothermal power now and future is also discussed. The economics, availability, and reliability of geothermal plants are reviewed.

Summary Three drillstring fatigue failures occurred while drilling two deep wells below 16,500 ft true-vertical depth (TVD) in the US midcontinent region. All the failures occurred across 2°/100 ft- to 3°/100 ft-dogleg severity (DLS) intervals from 6,000 to 8,000 ft. The well conditions (i.e., pipe condition and directional plan) were not significantly different from other deep wells in the area, which had not failed. A deep-well drillstring failure study was conducted, which included a review of drillstring-inspection reports, daily drilling reports, digital data, technical literature, and engineering analysis for the two wells. A cumulative fatigue analysis (CFA) modeling technique taking into account specific well conditions [i.e., wellbore geometry, rotary speed, rate of penetration (ROP), hook load, and drillstring configuration] was applied. The model indicated that drillstring failures would occur across shallow doglegs mainly because of high hang-down loads combined with slow ROP. The results of the study led to the development of new deep-well design criteria and implementation of new drilling guidelines. The new guidelines included the use of look-ahead CFA modeling when approaching drillstring endurance limits to minimize drillpipe-fatigue failures. Look-ahead CFA modeling and the new drilling guidelines were used on two subsequent deep wells in the area, leading to successful drilling to total depth (TD) of 18,000 ft TVD without failure. One of the wells had a 1.4°/100-ft DLS (calculated based on 100-ft survey spacing) at 1,500 ft, and drillpipe shuffling was required to prevent drillstring failure in the deep-hole section. The drillstring-fatigue failure prevention guidelines apply to deep wells drilled worldwide. Introduction BP America, Inc. experienced three high-load cyclic fatigue tube failures while drilling in the US midcontinent region's deep Anadarko basin. All of the failures occurred within a four-month period on two wells drilled by different rigs. The three fatigue failures occurred in the highest shallow dogleg interval of the wells, and all three failures were in the inclination-angle dropping section of the well. In Well A, poor mud properties caused the hole to pack off, leading to a heat-related tensile failure of a crossover in the bottomhole assembly (BHA). An unsuccessful fishing job for the remaining BHA led to a sidetrack. The sidetrack around the fish created shallow doglegs and led to the two drillpipe-fatigue failures in Well A. Shallow directional walk problems combined with a small directional target created shallow doglegs in Well B. The well scope was also changed at TD to drill 375 ft deeper. Mud circulation was lost, and the drillstring was rotated without circulation while building mud volume. Well B subsequently experienced a fatigue failure while pulling out of the hole at TD of 16,628 ft. After these failures occurred, a comprehensive study was performed to understand why these two wells experienced drillpipe failures while other area wells with similar conditions did not experience a failure. The study included a review of drillpipe-inspection reports, daily drilling reports, digital drilling recorder data, and engineering analysis.

Drilling ultra-deep (UD) wells places significant requirements on the drill string. Lengthy drill strings lead to high tensile loads which can lead to slip crushing of the drill string, hoisting capacity issues and drill pipe collapse capacity concerns at the blowout preventer (BOP). BOP shear rams may also have difficulty shearing today's high strength, high toughness drill pipe. BHA connection failures pose greater risk and cost at UD well depths. This paper analyzes the many challenges associated with drill string designs specifically for UD drilling. It presents emerging drill string technologies that are solutions expected to increase depth capability for the industry's continued advancement of deep drilling operations.

A critical cost in future deep oil and gas recovery is the cost to drill a well. This cost is dominated by the rate of penetration (ROP) that becomes increasingly important with increasing depth. Improving the technology of drilling and increasing the ROP will lower the cost to drill a well. This improves the economics of deep exploration and development, potentially increasing drilling activity, increasing production and supply, lowering the cost to the consumer and improving the economy. Industry partners and the U.S. Department of Energy (DOE) successfully completed benchmark testing of advanced diamond bits and high pressure/high temperature (HP/HT) drilling fluids at high pressures. The paper describes the results of this testing and identifies factors limiting ROP performance at great depth, and the development of drilling fluid systems and bit design philosophy to significantly improve drilling performance. Benchmark results match very well with data from target field applications. This project is part of the DOE Deep Trek program. Sixteen full-scale tests of 6 inch bits were conducted at wellbore pressures greater than 10,000 psi. Results from high-pressure tests with water and base oil showed very high ROPs are possible before mudding up. When drilling through hard sandstone penetration rates can drop 70 to 80% on switching to a weighted mud. These data emphasize the importance of mud technology in high-pressure applications. Performance of polycrystalline diamond compact (PDC) bits showed in many cases substantial improvements over roller cone insert bits. Cuttings from Carthage marble and Mancos shale appear to be compressed agglomerates of fine particles and Carthage marble cuttings had low compressive strengths. The study has concluded that opportunities for improvements in both bit design and smart HP/HT drilling fluids are possible. While rock properties change continuously with pressure the cutting mechanisms at great depths change much more dramatically. Changes in bit design and mud composition, using next generation technology, will be evaluated in Phase II testing. The significance of improved ROP for deep oil and gas plays include opportunities to reduce well costs and improve the economics of deep exploration and development plays. The net result for operators is cost reduction as well as an improved position on reserves.

KOC has been drilling deep HPHT wells from the mid 1980’s, and during this time the Kuwait deep well prospects have become deeper and more challenging. The rigs utilized to drill these wells have evolved over the years to meet these challenges, with new technologies being used to improve both operational and safety aspects. Five years ago an enhanced rig type upgrade was introduced with the application of Top Drive, additional third 1700 HP mud pump and larger 5 1/2" O.D. drill pipe. This resulted in a step-change improvement in drilling performance. In 2003 KOC began a project to look into the radical re-design of the deep rig specifications. Hamad Al Hamad and Partners was awarded the contract to complete the detailed design, procure and operate the rig, and National Oilwell Varco was assigned as the main rig construction contractor. For the rig design certain new concepts were to be developed in readiness for a future campaign of deep HPHT exploration wells. These included the following; the rig should be safer and more automated, the capacity of the main equipment items and the mud system should be state of the art both in capacity and equipment specifications, the 15M BOP stacks should be re-designed to minimize handling, and the rig should be adapted for operation in the harsh summer conditions in Kuwait. This paper will discuss the evolution of Deep Drilling Rig design in Kuwait, the design and specification of the new HAH-124 rig plus the construction/rig-up of the unit. The case study will also focus on lessons learned during this process and conclude with recommendations for future new rig builds.

The poor removal of chips in deep drilling of small diameter is often the cause of tool breakage and poor quality surface. The vibratory drilling enables the chip to be split thanks to the axial vibrations of the drill self-maintained by the cutting energy. Therefore chips are then evacuated easily. A specific tool holder with a variable axial stiffness was developed by the authors. The amplitude of the vibrations is greater than the feed rate. Vibratory drilling has been modelled to predict the cutting conditions and the adjustment of the stiffness of the tool holder. The models and the performances of the self-excited vibratory drilling process were validated by an experimental study.

The industry cost shared program aims to benchmark drilling rates of penetration in selected simulated deep formations and to significantly improve ROP through a team development of aggressive diamond product drill bit--fluid system technologies. Overall the objectives are as follows: Phase 1--Benchmark ''best in class'' diamond and other product drilling bits and fluids and develop concepts for a next level of deep drilling performance; Phase 2--Develop advanced smart bit-fluid prototypes and test at large scale; and Phase 3--Field trial smart bit-fluid concepts, modify as necessary and commercialize products. As of report date, TerraTek has concluded all major preparations for the high pressure drilling campaign. Baker Hughes encountered difficulties in providing additional pumping capacity before TerraTek's scheduled relocation to another facility, thus the program was delayed further to accommodate the full testing program.

Geothermal power generation technology is limited to those locations where the natural heat of the Earth is relatively near the surface and can therefore be accessed with conventional drilling techniques. The ability to extract the heat of the earth at greater depths and not be restricted to certain locations will revolutionize the geothermal industry. With this new heat mining technology, there will be no release to atmosphere of carbon dioxide, hydrogen sulfide, or hydrocarbons as is typical of current geothermal plants. Heat mining is also the key to truly renewable geothermal power generation. Integral to the concept of geothermal heat mining is the need to develop deep drilling methods and technology. Most geothermal wells are less that 3000 meters deep, and temperatures are usually less than 250/spl deg/C. Successful heat mining plant will need to tap into heat resources six to ten kilometers below the surface, a depth not yet economically attainable with current drilling technology. Improved technology is required to handle temperatures which could exceed 500/spl deg/C at depth. This paper presents the potential economic benefits of reducing the cost of deep drilling methods for heat mining by 50% over the next ten years.

NASA's Mars Exploration Program includes science goals related to life, climate, geology, and preparation for human exploration. Many of the investigations needed to reach these goals are enabled by long-term, continuous surface presence with logistical support. These capabilities can be provided by a progressive series of missions that establish and maintain a long-lived robotic presence, i.e. a Mars Outpost. To investigate the issues associated with robotic outpost design, the JPL Mars Long Range Planning Team developed and studied a heuristic outpost scenario. Major goals of the study included identifying: (1) which science objectives benefit from an outpost setting, (2) technology needs to fulfill mission requirements, and (3) operational/logistical challenges associated with multi-mission planning. This paper describes an outpost designed with the aforementioned goals in mind. The design focuses on subsurface mapping and characterization, accomplished through seismic mapping and deep drilling.

As the search for recoverable oil reserves moves to smaller, deeper, and hotter wells, measurements while drilling (MWD) requirements have grown increasingly challenging. MWD tools must survive temperatures of up to 350°F (175°C), pressures of up to 22,000 psi, and a wide variety of mud conditions. Moreover, deeper wells cause higher attenuation of the MWD signals and therefore require more signal power downhole. This paper presents the development of a new-generation retrievable MWD tool that has been proven to deliver the reliability required by the industry, even in deep, high pressure, hot wells. Four case studies illustrate the tool's reliability and performance under extreme conditions: In the Villafortuna field in Italy, this new generation MWD tool drilled the deepest horizontal well in the world, at depths greater than 20,000 ft with a maximum circulation temperature of 356°F (180°C) and downhole pressures exceeding 20,000 psi. In the Gulf of Mexico, the tool enabled BP to complete a deepwater well at a depth of 26,442 ft with a flow rate as low as 62 gpm, extending the far reaching capabilities of slimhole MWD equipment. In the Austin chalk in Texas, the tool operated reliably in drilling muds containing 30% solids. The tool operating life was increased by a factor of three through design improvements. The final case study documents the benefits of a tool designed for extreme environments, when used in difficult but not extreme conditions. An exemplary run of 315 hours at 287°F (142°C) is discussed. This new generation of slimhole MWD technology finally meets the challenges presented by the deeper and hotter wells at the leading edge of petroleum exploration.

DEEP DRILLING TO EXPLOIT GEOTHERMAL ENERGY INVOLVES RISKS RELATED TO ENGINEERING, FINANCING AND NON-DISCOVERY. FEASIBILITY STUDIES CONDUCTED AT AN EARLY STAGE OF THE PROJECT POINT THE WAY TO SUCCESSFUL EXPLOITATION OF GEOTHERMAL ENERGY. THE KEY TASK OF THESE STUDIES LIES IN THE SYSTEMATIC DISCLOSURE OF THE RISKS AND OPPORTUNITIES INVOLVED IN A PROJECT, EXPLAIN HUBERT SACHER AND RENE SCHIEMANN OF TUV SUD INDUSTRIE SERVICE.

In recent years, many wells have been constructed that are subject to extreme conditions. Two extreme conditions that can pose a particular challenge during the completion of a well are low temperature, for example in deepwater applications, and high-pressure and high-temperature, encountered in HPHT wells. The products and processes that are normally used to cement wells may be insufficient to create zonal isolation for these extreme conditions. This paper presents methods to help design and execute effective cement jobs for HPHT and deepwater, low temperature wells. First of all, recommendations are outlined for the deepwater conditions. Drilling fluid removal, sealant placement, and sealant sheath strength development are all affected by extreme conditions and are therefore designed accordingly. In order to help determine how strong the sealant sheath needs to be, formation properties are taken into account as well as the operations to be performed during the life of the well. These operations include well testing, stimulation, production, and injection. The paper goes on to discuss the advantages of new products and processes for cement wells under extreme conditions. The laboratory testing procedures, pre-job design procedures, job implementation and evaluation procedures that were used to test the new products and processes are described. Finally, guidelines are given for optimized designs for HPHT and low temperature wells using these products and processes.

Modern geoscience relies on fundamentals derived as much as a century ago under the severe constraints on observational knowledge of those early days. Brilliant geophysical and geochemical technology today depends for its application on 19th century geology, the principles of which fail to take into account new observational knowledge. From cold fusion to the red shift, much has been written opining the resistance to new ideas in science. Incongruent new data are ignored when theory fails to support observation. Instead of dealing with the fundamentals, scientists prefer to tinker with existing theory.

This report gives an account of the activities of the OECD Megascience Forum following its creation in June 1992, in particular the reviews of two areas of megascience: Astronomy and deep drilling (both deep sea and continental). It presents the main policy conclusions reached by the Megascience Forum on these areas. It also give an indication of ongoing and future work. With regard to ongoing and future work, the Forum will review at its next meeting, in July 1993, the area of global change research, and for this purpose an expert meeting was held in late March 1993 in Cambridge, Mass. (USA). Areas to be reviewed later in 1993 include oceanography, and neutron sources and synchrotron radiation sources as multipurpose facilities for the study of condensed matter, as well as for other applications such as element transmutation. The Megascience Forum will also undertake to discuss generic science and technology policy issues related to the development and management of megascience, starting with a discussion, at its next meeting, of national decision-making structure and processes.

This report gives an account of the activities of the OECD Megascience Forum following its creation in June 1992, in particular the reviews of two areas of megascience: Astronomy and deep drilling (both deep sea and continental). It presents the main policy conclusions reached by the Megascience Forum on these areas. It also give an indication of ongoing and future work. With regard to ongoing and future work, the Forum will review at its next meeting, in July 1993, the area of global change research, and for this purpose an expert meeting was held in late March 1993 in Cambridge, Mass. (USA). Areas to be reviewed later in 1993 include oceanography, and neutron sources and synchrotron radiation sources as multipurpose facilities for the study of condensed matter, as well as for other applications such as element transmutation. The Megascience Forum will also undertake to discuss generic science and technology policy issues related to the development and management of megascience, starting with a discussion, at its next meeting, of national decision-making structure and processes.

The first section of this Volume will discuss the ''Conventional Drilling System''. Today's complex arrangement of numerous interacting systems has slowly evolved from the very simple cable tool rigs used in the late 1800s. Improvements to the conventional drilling rig have varied in size and impact over the years, but the majority of them have been evolutionary modifications. Each individual change or improvement of this type does not have significant impact on drilling efficiency and economics. However, the change is almost certain to succeed, and over time--as the number of evolutionary changes to the system begin to add up--improvements in efficiency and economics can be seen. Some modifications, defined and described in this Volume as Advanced Modifications, have more than just an evolutionary effect on the conventional drilling system. Although the distinction is subtle, there are several examples of incorporated advancements that have had significantly more impact on drilling procedures than would a truly evolutionary improvement. An example of an advanced modification occurred in the late 1970s with the introduction of Polycrystalline Diamond Compact (PDC) drill bits. PDC bits resulted in a fundamental advancement in drilling procedures that could not have been accomplished by an evolutionary improvement in materials metallurgy, for example. The last drilling techniques discussed in this Volume are the ''Novel Drilling Systems''. The extent to which some of these systems have been developed varies from actually being tested in the field, to being no more than a theoretical concept. However, they all have one thing in common--their methods of rock destruction are fundamentally different from conventional drilling techniques. When a novel drilling system is introduced, it is a revolutionary modification of accepted drilling procedures and will completely replace current techniques. The most prominent example of a revolutionary modification in recent history was the complete displacement of cable tool rigs by rotary drilling rigs in the late 1920s.

Deep research drilling will encounter temperatures exceeding those normally encountered in standard oil and gas exploration and production. The traditional oil-field service companies have capabilities to temperatures of 120–150 ˚C. Consequently, many problems occur with the drilling equipment, muds, and logging tools at higher temperatures. However, there is a wealth of technology in the geothermal drilling programs where well completions at 250 ˚C are common, at 300 ˚C are frequent, and at 350 ˚C exist on a few wells. Also, materials, mechanical designs, and diagnostic techniques are developed for engines, gas turbines, and other systems that run at temperatures close to 1000 ˚C. All of these systems can be tapped for technologies used in high-temperature deep drilling. The major limitation to such development is lack of commercial interest in high-temperature drilling; companies are not willing to provide the needed field hardware.

The international Ocean Drilling Program (ODP) and the Continental Deep Drilling Program of the Federal Republic of Germany (KTB) are large exploration projects in which core-calibrated borehole measurements play an important scientific role. In the organizations that run both projects, separate working groups are responsible for planning the borehole logging program, supervising the downhole operations, stimulating the research and development of interpretation methods, and initiating new tool designs and developments. These groups came together September 13–15, 1989, for a meeting at the KTB drill site laboratory in Windischeschenbach, Oberpfalz, FRG. Conveners were Ralph Hanel (NLfB, Hannover, FRG) and Paul F. Worthington (BP Research Centre, Sunbury-on-Thames, U.K.) About 50 scientists attended. They agreed that integrated working groups be established, through which the two programs could collaborate even more closely in borehole logging.