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Rock heat-loss shape factors for Subterrene penetrators

Description: Results of calculations to predict heat losses to surrounding rock for Subterrene rock-melting penetrators of various shapes are presented in nondimensional form that can be applied to a range of axisymmetric penetrator geometries. Theoretical upper and lower limits are placed on a dimensionless time parameter, which includes penetrator dimensions, rock properties, and penetration rate. At these limits, heat losses either approach zero or are unaffected by penetrator geometry and velocity. The estimated heat losses from the nondimensional parameters agree well with experimental data and numerically calculated results. (auth)
Date: October 1, 1973
Creator: Cort, G.E.
Partner: UNT Libraries Government Documents Department

Optimization of Operating Parameters for Minimum Mechanical Specific Energy in Drilling

Description: Efficiency in drilling is measured by Mechanical Specific Energy (MSE). MSE is the measure of the amount of energy input required to remove a unit volume of rock, expressed in units of energy input divided by volume removed. It can be expressed mathematically in terms of controllable parameters; Weight on Bit, Torque, Rate of Penetration, and RPM. It is well documented that minimizing MSE by optimizing controllable factors results in maximum Rate of Penetration. Current methods for computing MSE make it possible to minimize MSE in the field only through a trial-and-error process. This work makes it possible to compute the optimum drilling parameters that result in minimum MSE. The parameters that have been traditionally used to compute MSE are interdependent. Mathematical relationships between the parameters were established, and the conventional MSE equation was rewritten in terms of a single parameter, Weight on Bit, establishing a form that can be minimized mathematically. Once the optimum Weight on Bit was determined, the interdependent relationship that Weight on Bit has with Torque and Penetration per Revolution was used to determine optimum values for those parameters for a given drilling situation. The improved method was validated through laboratory experimentation and analysis of published data. Two rock types were subjected to four treatments each, and drilled in a controlled laboratory environment. The method was applied in each case, and the optimum parameters for minimum MSE were computed. The method demonstrated an accurate means to determine optimum drilling parameters of Weight on Bit, Torque, and Penetration per Revolution. A unique application of micro-cracking is also presented, which demonstrates that rock failure ahead of the bit is related to axial force more than to rotation speed.
Date: May 25, 2011
Creator: Hamrick, Todd
Partner: UNT Libraries Government Documents Department

An Industry/DOE Program to Develop and Benchmark Advanced Diamond Product Drill Bits and HP/HT Drilling Fluids to Significantly Improve Rates of Penetration

Description: A deep drilling research program titled 'An Industry/DOE Program to Develop and Benchmark Advanced Diamond Product Drill Bits and HP/HT Drilling Fluids to Significantly Improve Rates of Penetration' was conducted at TerraTek's Drilling and Completions Laboratory. Drilling tests were run to simulate deep drilling by using high bore pressures and high confining and overburden stresses. The purpose of this testing was to gain insight into practices that would improve rates of penetration and mechanical specific energy while drilling under high pressure conditions. Thirty-seven test series were run utilizing a variety of drilling parameters which allowed analysis of the performance of drill bits and drilling fluids. Five different drill bit types or styles were tested: four-bladed polycrystalline diamond compact (PDC), 7-bladed PDC in regular and long profile, roller-cone, and impregnated. There were three different rock types used to simulate deep formations: Mancos shale, Carthage marble, and Crab Orchard sandstone. The testing also analyzed various drilling fluids and the extent to which they improved drilling. The PDC drill bits provided the best performance overall. The impregnated and tungsten carbide insert roller-cone drill bits performed poorly under the conditions chosen. The cesium formate drilling fluid outperformed all other drilling muds when drilling in the Carthage marble and Mancos shale with PDC drill bits. The oil base drilling fluid with manganese tetroxide weighting material provided the best performance when drilling the Crab Orchard sandstone.
Date: June 30, 2007
Creator: TerraTek
Partner: UNT Libraries Government Documents Department

Advanced Ultra-High Speed Motor for Drilling

Description: Three (3) designs have been made for two sizes, 6.91 cm (2.72 inch) and 4.29 cm (1.69 inch) outer diameters, of a patented inverted configured Permanent Magnet Synchronous Machines (PMSM) electric motor specifically for drilling at ultra-high rotational speeds (10,000 rpm) and that can utilize advanced drilling methods. Benefits of these motors are stackable power sections, full control (speed and direction) of downhole motors, flow hydraulics independent of motor operation, application of advanced drilling methods (water jetting and abrasive slurry jetting), and the ability of signal/power electric wires through motor(s). Key features of the final designed motors are: fixed non-rotating shaft with stator coils attached; rotating housing with permanent magnet (PM) rotor attached; bit attached to rotating housing; internal channel(s) in a nonrotating shaft; electric components that are hydrostatically isolated from high internal pressure circulating fluids ('muds') by static metal to metal seals; liquid filled motor with smoothed features for minimized turbulence in the motor during operation; and new inverted coated metal-metal hydrodynamic bearings and seals. PMSM, Induction and Switched Reluctance Machines (SRM), all pulse modulated, were considered, but PMSM were determined to provide the highest power density for the shortest motors. Both radial and axial electric PMSM driven motors were designed with axial designs deemed more rugged for ultra-high speed, drilling applications. The 6.91 cm (2.72 inch) OD axial inverted motor can generate 4.18KW (5.61 Hp) power at 10,000 rpm with a 4 Nm (2.95 ft-lbs) of torque for every 30.48 cm (12 inches) of power section. The 6.91 cm (2.72 inch) OD radial inverted motor can generate 5.03 KW (6.74 Hp) with 4.8 Nm (3.54 ft-lb) torque at 10,000 rpm for every 30.48 cm (12 inches) of power section. The 4.29 cm (1.69 inch) OD radial inverted motor can generate 2.56 KW (3.43 Hp) power with 2.44 Nm ...
Date: March 31, 2007
Creator: LLC, Impact Technologies & Arlington, University of Texas at
Partner: UNT Libraries Government Documents Department

Optimization of Deep Drilling Performance - Development and Benchmark Testing of Advanced Diamond Product Drill Bits & HP/HT Fluids to Significantly Improve Rates of Penetration

Description: This document details the progress to date on the OPTIMIZATION OF DEEP DRILLING PERFORMANCE--DEVELOPMENT AND BENCHMARK TESTING OF ADVANCED DIAMOND PRODUCT DRILL BITS AND HP/HT FLUIDS TO SIGNIFICANTLY IMPROVE RATES OF PENETRATION contract for the year starting October 2004 through September 2005. 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 Phase 1 testing and is planning Phase 2 development.
Date: September 30, 2005
Creator: Black, Alan & Judzis, Arnis
Partner: UNT Libraries Government Documents Department

Conceptual design of a coring Subterrene Geoprospector

Description: A rock-melting Subterrene system is described that can obtain a continuous core along the projected route of a tunnel. System specifications, individual component functions, preliminary design concepts, and design alternatives are included; and subcomponents that can be assembled from commercially available hardware are indicated. The device requires 150 kW of electric power to melt an accurate 300-mm (1-ft)-dia glass-lined hole and removes a 200-mm (8-in.)-dia glass-cased core at an advance rate of 0.4 mm/s (5 ft/h). The accurate hole diameter and stable hole lining allow the use of a packer- thruster located at the heated holemelting and hole-forming penetrator assembly. An orientation sensor and a guidance unit can also be located in this assembly. A hollow, flexible stem trailing behind the assembly contains the electric-power, coolant, and instrumentation lines, and provides a passage for debris removal. Core sections are removed through the flexible stem intermittently with wire-line core-retrieval hardware. This Subterrene system, named Geoprospector, is essentially a self-propelled and surface-guided minitunneler. It is a logical major development step in the Subterrene prograrm, directed toward a larger- diameter tunneling machine. Other practical Geoprospector applications are the forming of holes under obstacles such as rivers, highways, buildings, or other structures to accommodate utility lines or cables; the implantation of urban utilities; and the installation of underground pipelines or power-transmission lines without ditching. (auth)
Date: February 1, 1974
Creator: Neudecker, J.W.
Partner: UNT Libraries Government Documents Department

Versatile rock-melting system for the formation of small-diameter horizontal glass-lined holes

Description: Rock-melting penetrators with diameters ranging from 50 mm (2 in.) to 76 mm (3 in.) have reached a stage of development at the Los Alamos Scientific Laboratory (LASL) which suggests that these devices are ready for practical application. Prototype refractory metal penetrators have formed glass-cased vertical holes of 26 m (82 ft) in a single run, and horizontal holes with diameters up to 127 mm (5 in.) are expected in the near future. These small horizontal holes can be used for underground utility conduits; for high-explo sive shot emplacement; and as drainage holes to stabilize road cuts or embankments. Design concepts and preliminary specifications are described for a Subterrene system that forms small-diameter horizontal holes in rock by melting and simultaneously lines the hole with glassy rock melt. Most components of the system are commercially available. Deviation sensors and alignment-control units can be added to ensure that the holes are straight. The design and operation of this Subterrene system are described and proposed development approaches for the hole-forming assembly are discussed. (auth)
Date: October 1, 1973
Creator: Sims, D.L.
Partner: UNT Libraries Government Documents Department

Superhard nanophase cutter materials for rock drilling applications

Description: The Low Pressure-High Temperature (LPHT) System has been developed for sintering of nanophase cutter and anvil materials. Microstructured and nanostructured cutters were sintered and studied for rock drilling applications. The WC/Co anvils were sintered and used for development of High Pressure-High Temperature (HPHT) Systems. Binderless diamond and superhard nanophase cutter materials were manufactured with help of HPHT Systems. The diamond materials were studied for rock machining and drilling applications. Binderless Polycrystalline Diamonds (BPCD) have high thermal stability and can be used in geothermal drilling of hard rock formations. Nanophase Polycrystalline Diamonds (NPCD) are under study in precision machining of optical lenses. Triphasic Diamond/Carbide/Metal Composites (TDCC) will be commercialized in drilling and machining applications.
Date: June 23, 2000
Creator: Voronov, O.; Tompa, G.; Sadangi, R.; Kear, B.; Wilson, C. & Yan, P.
Partner: UNT Libraries Government Documents Department

Measurement and analysis of chatter in a compliant model of a drillstring equipped with a PDC bit

Description: Typical laboratory testing of Polycrystalline Diamond Compact (PDC) bits is performed on relatively rigid setups. Even in hard rock, PDC bits exhibit reasonable life using such testing schemes. Unfortunately, field experience indicates otherwise. In this paper, the authors show that introducing compliance in testing setups provides better simulation of actual field conditions. Using such a scheme, they show that chatter can be severe even in softer rock, such as sandstone, and very destructive to the cutters in hard rock, such as sierra white granite.
Date: November 9, 1999
Creator: Elsayed, M.A. & Raymond, D.W.
Partner: UNT Libraries Government Documents Department

OPTIMIZATION OF MUD HAMMER DRILLING PERFORMANCE - A PROGRAM TO BENCHMARK THE VIABILITY OF ADVANCED MUD HAMMER DRILLING

Description: This document details the progress to date on the ''OPTIMIZATION OF MUD HAMMER DRILLING PERFORMANCE--A PROGRAM TO BENCHMARK THE VIABILITY OF ADVANCED MUD HAMMER DRILLING'' contract for the quarter starting April 2003 through June 2003. The DOE and TerraTek continue to wait for Novatek on the optimization portion of the testing program (they are completely rebuilding their fluid hammer). Accomplishments included the following: (1) Hughes Christensen has recently expressed interest in the possibility of a program to examine cutter impact testing, which would be useful in a better understanding of the physics of rock impact. Their interest however is not necessarily fluid hammers, but to use the information for drilling bit development. (2) Novatek (cost sharing supplier of tools) has informed the DOE project manager that their tool may not be ready for ''optimization'' testing late summer 2003 (August-September timeframe) as originally anticipated. During 3Q Novatek plans to meet with TerraTek to discuss progress with their tool for 4Q 2003 testing. (3) A task for an addendum to the hammer project related to cutter impact studies was written during 2Q 2003. (4) Smith International internally is upgrading their hammer for the optimization testing phase. One currently known area of improvement is their development program to significantly increase the hammer blow energy.
Date: July 1, 2003
Creator: Judzis, Arnis
Partner: UNT Libraries Government Documents Department

DOWNHOLE VIBRATION MONITORING & CONTROL SYSTEM

Description: The deep hard rock drilling environment induces severe vibrations into the drillstring, which can cause reduced rates of penetration (ROP) and premature failure of the equipment. The only current means of controlling vibration under varying conditions is to change either the rotary speed or the weight-on-bit (WOB). These changes often reduce drilling efficiency. Conventional shock subs are useful in some situations, but often exacerbate the problems. The objective of this project is development of a unique system to monitor and control drilling vibrations in a ''smart'' drilling system. This system has two primary elements: (1) The first is an active vibration damper (AVD) to minimize harmful axial, lateral and torsional vibrations. The hardness of this damper will be continuously adjusted using a robust, fast-acting and reliable unique technology. (2) The second is a real-time system to monitor drillstring vibration, and related parameters. This monitor adjusts the damper according to local conditions. In some configurations, it may also send diagnostic information to the surface via real-time telemetry. The AVD is implemented in a configuration using magnetorheological (MR) fluid. By applying a current to the magnetic coils in the damper, the viscosity of the fluid can be changed rapidly, thereby altering the damping coefficient in response to the measured motion of the tool. Phase I of this program entailed modeling and design of the necessary subsystems and design, manufacture and test of a full laboratory prototype. Phase I of the project was completed by the revised end date of May 31, 2004. The objectives of this phase were met, and all prerequisites for Phase II have been completed. The month of June, 2004 was primarily occupied with the writing of the Phase I Final Report, the sole deliverable of Phase I, which will be submitted in the next quarter. Redesign of the ...
Date: October 13, 2004
Creator: Cobern, Martin E.
Partner: UNT Libraries Government Documents Department

DOWNHOLE VIBRATION MONITORING & CONTROL SYSTEM

Description: The deep hard rock drilling environment induces severe vibrations into the drillstring, which can cause reduced rates of penetration (ROP) and premature failure of the equipment. The only current means of controlling vibration under varying conditions is to change either the rotary speed or the weight-on-bit (WOB). These changes often reduce drilling efficiency. Conventional shock subs are useful in some situations, but often exacerbate the problems. The objective of this project is development of a unique system to monitor and control drilling vibrations in a ''smart'' drilling system. This system has two primary elements: (1) The first is an active vibration damper (AVD) to minimize harmful axial, lateral and torsional vibrations. The hardness of this damper will be continuously adjusted using a robust, fast-acting and reliable unique technology. (2) The second is a real-time system to monitor drillstring vibration, and related parameters. This monitor adjusts the damper according to local conditions. In some configurations, it may also send diagnostic information to the surface via real-time telemetry. The AVD is implemented in a configuration using magnetorheological (MR) fluid. By applying a current to the magnetic coils in the damper, the viscosity of the fluid can be changed rapidly, thereby altering the damping coefficient in response to the measured motion of the tool. Phase I of this program entailed modeling and design of the necessary subsystems and design, manufacture and test of a full laboratory prototype. Phase I of the project was completed by the revised end date of May 31, 2004. The objectives of this phase were met, and all prerequisites for Phase II have been completed.
Date: August 31, 2004
Creator: Cobern, Martin E.
Partner: UNT Libraries Government Documents Department

Rapid excavation by rock melting. LASL subterrene program, December 31, 1972--September 1, 1973

Description: Research is continuing on establishing the technical and economic feasibility of excavation systems based upon the rockmelting (Subterrene) concept. A series of electrically powered, small-diameter prototype melting penetrators have been developed and tested. Research activities include optimizing penetrator configurations, designing high-performance heater systems, and improving refractory-metals technology. The properties of the glass linings that are automatically formed on the melted holes are being investigated for a wide variety of rocks and soils. Thermal and fluid-mechanics analyses of the melt flows are being conducted with the objective of optimizing penetraton designs. Initial economic models of the rock-melting concept extended to large tunnelers are being developed. Field tests and demonstrations of the prototype devices continue to be performed in a wide range of rock and soil types. The conceptual design of the electrically powered, self-propelled, remotely guided, horizontal tunnel-alignment prospecting system (Geoprospector) has been initiated. Such a device will also find applications in energy transmission, i.e., utility and pipeline installations. The long-term goal of the research is to develop the technology and prototype hardware that will ultimately lead to large tunneling devices, with improved advance rates and reduced tunnel project costs. The rockmelting concept includes elements that will result in innovative solutions to the three major functional areas of tunneling: rock disintegration, materials handling, and hole-support linings. The proposed excavation method, which is relatively insensitive to variations in rock formation, produces a liquid melt that can be chilled to a glass and formed into a dense, strong, firmly attached hole lining. Unique applications to large automated tunneling systems, ultradeep coring for geoscience research, and hot-rock penetration for geothermal energy development are being investigated, (auth)
Date: November 1, 1973
Creator: Hanold, R. J.
Partner: UNT Libraries Government Documents Department

Protected Polycrystalline Diamond Compact Bits For Hard Rock Drilling

Description: Two bits were designed. One bit was fabricated and tested at Terra-Tek's Drilling Research Laboratory. Fabrication of the second bit was not completed due to complications in fabrication and meeting scheduled test dates at the test facility. A conical bit was tested in a Carthage Marble (compressive strength 14,500 psi) and Sierra White Granite (compressive strength 28,200 psi). During the testing, Hydraulic Horsepower, Bit Weight, Rotation Rate, were varied for the Conical Bit, a Varel Tricone Bit and Varel PDC bit. The Conical Bi did cut rock at a reasonable rate in both rocks. Beneficial effects from the near and through cutter water nozzles were not evident in the marble due to test conditions and were not conclusive in the granite due to test conditions. At atmospheric drilling, the Conical Bit's penetration rate was as good as the standard PDC bit and better than the Tricone Bit. Torque requirements for the Conical Bit were higher than that required for the Standard Bits. Spudding the conical bit into the rock required some care to avoid overloading the nose cutters. The nose design should be evaluated to improve the bit's spudding characteristics.
Date: October 31, 2000
Creator: Cardenas, Robert Lee
Partner: UNT Libraries Government Documents Department

Optimization of Mud Hammer Drilling Performance--A Program to Benchmark the Viability of Advanced Mud Hammer Drilling

Description: Operators continue to look for ways to improve hard rock drilling performance through emerging technologies. A consortium of Department of Energy, operator and industry participants put together an effort to test and optimize mud driven fluid hammers as one emerging technology that has shown promise to increase penetration rates in hard rock. The thrust of this program has been to test and record the performance of fluid hammers in full scale test conditions including, hard formations at simulated depth, high density/high solids drilling muds, and realistic fluid power levels. This paper details the testing and results of testing two 7 3/4 inch diameter mud hammers with 8 1/2 inch hammer bits. A Novatek MHN5 and an SDS Digger FH185 mud hammer were tested with several bit types, with performance being compared to a conventional (IADC Code 537) tricone bit. These tools functionally operated in all of the simulated downhole environments. The performance was in the range of the baseline ticone or better at lower borehole pressures, but at higher borehole pressures the performance was in the lower range or below that of the baseline tricone bit. A new drilling mode was observed, while operating the MHN5 mud hammer. This mode was noticed as the weight on bit (WOB) was in transition from low to high applied load. During this new ''transition drilling mode'', performance was substantially improved and in some cases outperformed the tricone bit. Improvements were noted for the SDS tool while drilling with a more aggressive bit design. Future work includes the optimization of these or the next generation tools for operating in higher density and higher borehole pressure conditions and improving bit design and technology based on the knowledge gained from this test program.
Date: March 1, 2006
Creator: Judzis, Arnis
Partner: UNT Libraries Government Documents Department

Development and testing of a Mudjet-augmented PDC bit.

Description: This report describes a project to develop technology to integrate passively pulsating, cavitating nozzles within Polycrystalline Diamond Compact (PDC) bits for use with conventional rig pressures to improve the rock-cutting process in geothermal formations. The hydraulic horsepower on a conventional drill rig is significantly greater than that delivered to the rock through bit rotation. This project seeks to leverage this hydraulic resource to extend PDC bits to geothermal drilling.
Date: January 1, 2006
Creator: Black, Alan (TerraTek, Inc.); Chahine, Georges (DynaFlow, Inc.); Raymond, David Wayne; Matthews, Oliver (Security DBS); Grossman, James W.; Bertagnolli, Ken (US Synthetic) et al.
Partner: UNT Libraries Government Documents Department

Subterrene electrical heater design and morphology

Description: The design, construction, and testing of a variety of electrical heaters for small-diameter Subterrene penetrators has been pursued. The incompatibility of refractory materials at the required operating temperatures of ~2000 deg K and the large heat-flux requirements posed the most difflcult design problems. Heat fluxes of up to 2.0 MW/m/sup 2/ were obtained from pyrolytic-graphite radiant heattransfer elements and were as high as 2.5 MW/m/sup 2/ when this type of heater was combined with a lithium heat-pipe assembly. Penetrators using radiant heaters produced both vertical and horizontal holes of 50 mm dia up to lengths of 25 m, whereas holes of up to 64 mm dia and 0.5 m long were produced in basalt and other rock samples in the laboratory. (auth)
Date: February 1, 1974
Creator: Armstrong, P.E.
Partner: UNT Libraries Government Documents Department

Heat transfer and thermal treatment processes in subterrene-produced glass hole linings

Description: Glass-forming and thermal treatment processes for the glass liners of bore holes produced by Subterrene rock-melting penetrators are considered. Analytical and numerical calculations of the radial temperature distributions and glass cooling rates are reported for the glass-like liners created by laboratory penetrators operating in local Los Alamos tuff and basalot. The temperature calculations are compared with experimenotal data. The cooling rate at the inside surface of othe glass liner is strongly influenced by the penetrator afterbody and stem design. To minimize residual stresses in the cooled glass, a qualitative correlaotion is found between this cooling rate and othe thermal properties of the parent rock. The magnitude of residual strains and stresses in glass produced by laboratory penetrators is estimated. (auth)
Date: February 1, 1974
Creator: Stanton, A.E.
Partner: UNT Libraries Government Documents Department

Laser Drilling - Drilling with the Power of Light

Description: Gas Technology Institute (GTI) has been the leading investigator in the field of high power laser applications research for well construction and completion applications. Since 1997, GTI (then as Gas Research Institute) has investigated several military and industrial laser systems and their ability to cut and drill into reservoir type rocks. In this report, GTI continues its investigation with a recently acquired 5.34 kW ytterbium-doped multi-clad high power fiber laser (HPFL). The HPFL represents a potentially disruptive technology that, when compared to its competitors, is more cost effective to operate, capable of remote operations, and requires considerably less maintenance and repair. To determine how this promising laser compares with other lasers used in past experimental work, GTI performed a number of experiments with results directly comparable to previous data. Experiments were designed to investigate the effect of laser input parameters on representative reservoir rock types of sandstone and limestone. The focus of the experiments was on completion and perforation applications, although the results and techniques apply to well construction and other rock cutting applications. Variables investigated include laser power, beam intensity, external purging of cut materials, sample orientation, beam duration, beam shape, and beam frequency. The investigation also studied the thermal effects on the two sample rock types and their methods of destruction: spallation for sandstone, and thermal dissociation for limestone. Optimal operating conditions were identified for each rock type and condition. As a result of this experimental work, the HPFL has demonstrated a better capability of cutting and drilling limestone and sandstone when compared with other military and industrial lasers previously tested. Consideration should be given to the HPFL as the leading candidate for near term remote high power laser applications for well construction and completion.
Date: September 28, 2004
Creator: Gahan, Brian C. & Batarseh, Samih
Partner: UNT Libraries Government Documents Department