Conventional Drilling Systems Research Articles

Field test of a Combined Thermo-Mechanical Drilling technology. Mode II: Flame-assisted rotary drilling

To enhance the drilling performance in deep hard rocks and reduce overall drilling efforts, this work proposes a Combined Thermo-Mechanical Drilling (CTMD) technology. This technology employs a heat source (e.g., a flame jet) and includes two main drilling modes: (I) thermal spallation drilling, investigated in the companion paper and (II) flame-assisted rotary drilling, investigated here as a field test. The CTMD technology is expected to reduce drilling efforts, especially in hard rocks, enhancing the rock penetration rate and increasing the bit lifetime, all of which reduces the drilling costs. The present work investigates Mode II (flame-assisted rotary drilling) of the CTMD technology by implementing the concept in an existing drilling rig and testing the technology under relevant process conditions. This contribution studies the underlying rock removal mechanism of CTMD and demonstrates its drilling performance, compared to conventional rotary drilling methods. Acoustic emission monitoring, and analysis of the collected drill cuttings provide multiple evidences for thermal-cracking-enhanced rock removal during the flame-assisted rotary drilling. This removal mechanism appears to represent an optimal compromise to minimize rock fragmentation and cutting transport efforts during drilling, compared to a less efficient mechanical scraping of the hard granite rock, observed during the standalone-mechanical drill test. The drilling performance, in terms of removal and wear rates, are evaluated for the flame-assisted rotary drilling. This shows that the proposed drilling approach is capable of enhancing the removal process in hard granite rock, by a factor of 2.5, compared to standalone-mechanical drilling. The implementation of this drilling approach into a conventional drilling system shows that integration of thermal assistance to conventional rotary drilling requires marginal technical efforts. Additionally, this technology can profit from established knowledge in conventional mechanical drilling, facilitating its implementation to improve drilling performance in hard rocks. Hence, this study demonstrates that the Combined Thermo-Mechanical Drilling method is feasible and concludes that this technology constitutes a promising approach to improve the drilling process, thereby increasing the viability of accessing deep geo-resources in hard rocks.

Improved Real–Time Estimation of Return Flow Rate of Drilling Fluids by Model Adaptation for Friction Parameter

Early kick and loss detection is a major concern in any drilling operation. A real-time return flow rate measurement would be an added advantage for the early kick and loss detection for conventional drilling systems. In this paper, the real-time estimation of the return flow rate during drilling is studied, using a Venturi channel. A reduced order, 1D, mathematical equation for the shallow water flow/open flow in the Venturi channel is investigated with various non-Newtonian friction models. The volumetric fluid flow rate is estimated online using an unscented Kalman filter. In order to improve the fluid flow rate estimation, the model is adapted to some of the rheological parameters in real time. A simple and effective fit–for–purpose friction model is developed and compared with the other friction models from literature. The fit–for–purpose model has the least estimation error (RMSE 1.465%) and requires less information as inputs. The proposed method exhibits promising potential to be used as an online return flow rate measurement for early kick and loss detection in conventional drilling.

Evaluation of primary stability for mandibular implant overdenture after osseodensification using Densah bur

Objectives: To evaluate the effect of osseodensification using Densah bur on the primary stability of mandibular implant overdenture. Materials and Methods: Ten completely edentulous patients were selected and two implants were inserted in the interforaminal region for each patient in a split mouth design; one implant with the conventional drilling system and one implant with the Densah bur drilling system. Implant primary stability was measured using Resonance Frequency Analysis by Osstell immediately after torqueing the implants and every two weeks for 2 months. Results: No significant difference was found regarding Osstell values at all follow up appointments for both groups. Conclusions: comparable results for primary stability with and without osseodensification which still requires further investigation with longer follow up period.

Optimising deepwater drilling safety and efficiency in Australia with closed-loop circulation drilling systems

Closed-loop circulation drilling (CLCD) systems provide an increasingly viable alternative to open-to-the-atmosphere conventional drilling systems by emphasising the use of closed and pressurisable systems to allow a scalable approach that produces a range of benefits. These range from increased personnel and environmental safety to better data resolution and even greater control over the drilling process. This paper states how CLCD addresses a need in a post-Macondo world, where deepwater drilling is under intense and increased regulatory control, by providing flexible systems that supplement the safety and efficiency of deepwater drilling operations. Furthermore, it describes the details of how CLCD systems can be installed and used on moored and dynamically positioned drilling vessels, and points out how it may be deployed for deepwater conditions in Australia. Recent successes and issues encountered in the application of this technology in the Asia Pacific region are also shared.

Temperature change in pig rib bone during implant site preparation by low-speed drilling

ObjectivesThe purpose of this study was to evaluate the temperature change during lowspeed drilling using infrared thermography.Material and MethodsPig ribs were used to provide cortical bone of a similar quality to human mandible. Heat production by three implant drill systems (two conventional drilling systems and one low-speed drilling system) was evaluated by measuring the bone temperature using infrared thermography. Each system had two different bur sizes. The drill systems used were twist drill (2.0 mm/2.5 mm), which establishes the direction of the implant, and finally a 3.0 mm-pilot drill. Thermal images were recorded using the IRI1001 system (Infrared Integrated Systems Ltd.). Baseline temperature was 31±1ºC. Measurements were repeated 10 times, and a static load of 10 kg was applied while drilling. Data were analyzed using descriptive statistics. Statistical analysis was conducted with two-way ANOVA.Results and ConclusionsMean values (n=10 drill sequences) for maximum recorded temperature (Max TºC), change in temperature (∆TºC) from baseline were as follows. The changes in temperature (∆TºC) were 1.57ºC and 2.46ºC for the lowest and the highest values, respectively. Drilling at 50 rpm without irrigation did not produce overheating. There was no significant difference in heat production between the 3 implant drill systems (p>0.05). No implant drill system produced heat exceeding 47ºC, which is the critical temperature for bone necrosis during low-speed drilling. Low-speed drilling without irrigation could be used during implant site preparation.

Laboratory experiments and thermal calculations for the development of a next-generation glacier-ice exploration system: Development of an electro-thermal drilling device

A next-generation drilling system, equipped with a thermal drilling device, is proposed for glacier ice. The system is designed to penetrate glacier ice via melting of the ice and continuously analyze melt-water in a contamination-free sonde. This new type of drilling system is expected to provide analysis data in less time and at less cost than existing systems. Because of the limited number of parameters that can be measured, the proposed system will not take the place of conventional drilling systems that are used to obtain ice cores; however, it will provide a useful method for quickly and simply investigating glacier ice. An electro-thermal drilling device is one of the most important elements needed to develop the proposed system. To estimate the thermal supply required to reach a target depth in a reasonable time, laboratory experiments were conducted using ice blocks and a small sonde equipped solely with heaters. Thermal calculations were then performed under a limited range of conditions. The experiments were undertaken to investigate the effects of the shape and material of the drill head and heater temperature on the rate of penetration into the ice. Additional thermal calculations were then performed based on the experimental results. According to the simple thermal calculations, if the thermal loss that occurs while heat is transferred from the heater to ice (in melting the ice) is assumed to be 50%, the total thermal supply required for heaters in the sonde and cable is as follows: (i) 4.8 kW (sonde) plus 0 W (cable) to penetrate to 300 m depth over 10 days into temperate glacier ice for which the temperature is 0 °C at all depths and to maintain a water layer along 300 m of cable; (ii) 10 kW (sonde) plus 19–32 kW (cable) to penetrate to 1000 m depth over 1 month into cold glacier ice for which the temperature is −25 °C at the surface and 0 °C at 1000 m depth and to maintain a water layer along 1000 m of cable; and (iii) 19 kW (sonde) plus 140–235 kW (cable) to penetrate to 3000 m depth over 2 months into an ice sheet for which the temperature is −55 °C at the surface and 0 °C at 3000 m depth and to maintain a water layer along 3000 m of cable. The thermal supply required for the cable is strongly affected by the thickness of the water layer, cable diameter, and the horizontal distance from the ice wall at which the ice temperature was maintained at its initial temperature. A large thermal supply is required to heat 3000 m of cable in an ice sheet (scenario (iii) above), but penetration into glacier ice (scenarios (i) and (ii) above) could be realistic with the use of a currently employed generator.

Accessing the Martian deep subsurface to search for life

To date there has been no data indicating that the surface of Mars is inhabited. Research conducted on Earth has revealed that life can exist deep beneath the surface of a planet. Current data from Mars missions suggesting the presence of liquid water early in Mars’ history and mathematical modeling of the fate of water on Mars imply that liquid water may exist deep beneath the surface of Mars. The existence of liquid water beneath the Martian surface, combined with life's ability to live chemolithoautotrophically, leads to the hypothesis that life may exist deep beneath the Martian surface. Acquisition and analyses of Martian subsurface samples will shed light on the possibility of extant or extinct life, in permafrost and liquid water, on Mars, the processes leading to the origin of life, and the size of the Solar System's habitable zone. The results of a workshop convened by NASA in 1998 suggest that no fewer than two missions could be considered for accessing the deep subsurface of Mars. This two mission scenario includes a mission penetrating to a depth of ∼300 m and a mission penetrating to a depth of ∼3 km . As in all space missions the power, mass and volume of the penetration system and all associated equipment to be used to gain access to the Martian subsurface must be kept to a minimum. One technique that may be applicable, but in need of further development, is an electrically heated probe (bit) that penetrates and cores by melting through rock. The probe is attached to an umbilical cable to provide power and to allow periodic retrieval of the probe. This approach appears to address planetary protection concerns and may decrease the mass, power and volume requirements of conventional drilling systems by eliminating the need for casing material, drilling fluids, and handling potentially contaminated debris from the bore hole. Deep drilling on Mars presents several planetary protection forward and back contamination issues. These issues include sample handling at the surface as well as upon return to Earth.

Canadian Coiled Tubing Horizontal Drilling: Technology And Applications

Abstract Canada has played a prominent role in the development of horizontal drilling technology. To date, over 1,400 "grassroots" and "re-entry" wells have been drilled. Although other countries have experienced greater numbers of wells, the number of different types, varieties, and formations tested with this technology in Canada is unparalleled. Due in part to the exponential growth of horizontal well applications since the mid-1980's, coiled tubing CCT) technology in Canada has been adapted and evolved for more traditional uses such as horizontal well stimulation, evaluation, workovers, and clean-outs. The principal nontraditional aspect of CT is its use in drilling operations. This paper will deal with the current state and recent advances in CT horizontal drilling in Canada, A brief historical perspective will be presented that highlights Canada's presence as a pioneer in CT drilling and documents its evolution from vertical re-entries dating back to 1974, grassroots vertical wells in 1976, to the industry's current efforts at vertical and horizontal CTD. The principal Canadian service companies are reviewed in terms of present capabilities in CTO applications and the perceived driving forces that are stimulating the development of this emerging technology. The key factors such as diameter and fatigue life of the coil, length limitations, bottom hole assemblies, surveying methods and the economic and market factors affecting CTO relative to more conventional drilling techniques are reviewed. Finally, the future technological, market and economic developments necessary for the successful implementation of CTO for grassroots vertical and horizontal well re-entry projects are suggested. Introduction The exponential growth in the number of horizontal well applications in Canada and internationally over the past eight years has led to a relatively rapid development of both personnel and equipment to enhance the horizontal drilling method of exploiting existing oil and gas pools. In Canada, there are an estimated 70,000 producing wells: 40,000 gas wells and 30,000 oil wells. Recently, the National Energy Board (NEB) presented a study on horizontal oil wells and their impact on future crude oil supply in Canada. They estimated that there is a potential market of over 12,000 horizontal wells that can be economically drilled within 1,800 oil pools at a market price of $20 US/Bbl. Of these 12,000 wells, 5,000 were believed to be grassroots in nature (1 I 100 have been drilled to date) while 7,000 were horizontal re-entries through existing cased wells (300 have been drilled to date). Of the 6,700 remaining re-entries, the competition for services will be between slim hole (less than or equal to 6–1/4 in. hole size) conventional drilling systems using drilling rigs or modified service rigs and coiled tubing drilling (CTD) technology. Add to this potential market vertical deepenings, horizontal lengthenings and grassroots wells coupled with increasing interest in horizontal exploitation of gas pools, and the development of CTD appears to be poised for exponential growth in Canada over the next five years. Some of the questions that will be addressed during the course of this paper are:

Advances In Remote-controlled Drilling

Abstract For over twenty years, the Institute Francais du Petrole has researched remote-controlled drilling. As wells go deeper and are more slanted, and sometimes horizontal, such facilities are essential. Control is by wireline transmission of bottom-hole data and control of downhole functions. There are three main components:–a directional unit (magnetic-accelerometer type);–a bottom-hole drilling parameters measuring unit (with various sensors to measure the required parameters, fully pressure compensated);–a variable-angle bent sub (rotation of the lower part of a sub around a tilted axis). (Figure in full paper) Operational results for the directional unit, and test data for the other components indicate satisfactory performance. In the future besides marketing existing industrialized tools, the design of tools in diameters other than the 7%-in. selected for the prototypes will be undertaken and sensors for measuring logging parameters and safety parameters will be added. Introduction The earliest application of directional drilling was in boreholes which were in bad shape and required side-tracking because of fish in the hole. Remote-control methods are, therefore, particularly useful. Directional wells are also needed to intersect with and kill wild wells. In 1962, the Institute Francais du Petrole launched a research· program in the area of telemetry and remote control(l). Directional drilling is now used on offshore platforms, to drill in faulted zones, in the presence of salt domes and in inaccessible terrain. The remote-controlled drilling system designed by the Institute Francais du Petrole consists of the following components:A powerful downhole motor, capable of drilling the entire well, including the highly slanted part, with conventional or heavy drill stems.A wireline telemetry system permanently connected during drilling to the downhole sensors for measurement of the directional parameters, including borehole azimuth, drift and bent sub position. Mechanical parameters such as weight on bit, torque, pressures and temperatures inside the drill stem and in(Figure in full paper)the annular space, and motor r.p.m, are recorded. Logging parameters, including mud resistivity inside and outside in the annular space, true resistivity and natural gamma radiation of the formations, are also transmitted.A variable-angle bent sub controlled from the surface by the same conducting wireline used to correct the trajectory.Surface equipment designed to read, record and process the above. Description of the System The remote-controlled drilling system (Fig. 1) adapts to conventional drilling systems with downhole motors. A downhole motor may be of the turbine or of the positive-displacement type. A TELEPILOTE variable-angle bent sub controlled from the surface, a TELEVIGILE drilling parameter measuring sub, an orienting sub and an AZINTAC directional measurement sonde placed inside a nonmagnetic drill collar make up the detecting devices. A single-conductor electrical cable runs through a lateral window sub into the annular space of the vertical or subvertical part of the borehole. A winch and conventional surface equipment are used to wind the cable. An electronic console equipped with a minicomputer performs data processing, display and recording.