No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Drilling large diameter holes in rocks using multiple laser beams
Abstract
Studies on drilling petroleum reservoir rocks with lasers show that modern infrared lasers have the capability to spall (thermally fragment), melt and vaporize natural earth materials with the thermal spallation being the most efficient rock removal mechanism. Although laser irradiance as low as 1000 W/cm² is sufficient to spall rock, firing the beam on a single spot for too long at that intensity causes rock melting and reduces removal efficiency. Also, it is difficult to visualize an efficient way to create a six or eight inch hole by sending one large beam down hole. Alternatives are either to raster the beam to cover the 20 cm hole area or, using a pattern of many small beams illuminated sequentially or in groups, create a nearly circular work face. This paper will present the testing results of the multiple small beam method. The effect on rock removal efficiency of several parameters, including relaxation time between laser bursts, basic patterns of multiple beams, and beam spot overlapping amounts are determined and presented.
... The latest fundamental research in this regard was introduced at the beginning of the 21st century. 1 Laser perforation is a new method in oil and gas wells, where the aim is to find an alternative fragmentation method to existing methods. ...
... High-powered laser beams have been widely applied in ablating or drilling materials. 1 As such, from 1997 onward, a group of scientists from the Gas Technology Institute (GTI, formerly Gas Research Institute); Colorado School of Mines; Argonne National Laboratory, Parker Geosciences Consulting and LLC studied the feasibility of rock drilling and oil and gas well perforation using high-powered lasers. 1 One of the major obstacles in using laser perforation in practice is beam delivery to deep wells which could be solved by using fiber optics beam delivery. 2 If the laser transmission difficulties to deep wells at long distances are resolved, then use of laser in drilling wells is strongly recommended in limestone res- ervoir rock such as Iranian oil reservoir rock. ...
... 1 As such, from 1997 onward, a group of scientists from the Gas Technology Institute (GTI, formerly Gas Research Institute); Colorado School of Mines; Argonne National Laboratory, Parker Geosciences Consulting and LLC studied the feasibility of rock drilling and oil and gas well perforation using high-powered lasers. 1 One of the major obstacles in using laser perforation in practice is beam delivery to deep wells which could be solved by using fiber optics beam delivery. 2 If the laser transmission difficulties to deep wells at long distances are resolved, then use of laser in drilling wells is strongly recommended in limestone res- ervoir rock such as Iranian oil reservoir rock. ...
Laser perforation of oil and gas wells is a new method for well completion as an alternative to
blasting methods. Under real perforation in oil and gas wells, three main factors have influence
on the laser perforation such as specific energy (i.e., energy required to remove the unit weight
of rock). These three factors are temperature, the hydraulic pressure of fluid flow, and confining
pressure. This paper investigates the role and significance of the coupled T-H-M (thermohydraulic-
mechanical) processes on specific energy (SE) and rate of penetration (RoP). For
physical modeling of T-H-M processes, a new cell and setup is designed and developed. In this
setup, a circular part of the front side of the cylindrical sample is open in order to interact with
the laser beam while the temperature, hydraulic pressure, and confining pressure are applied to
the sample. The rock tested under four temperature steps from 25 to 120 °C (temperature range
of major oil reservoir in fractured rocks), the hydraulic pressure was chosen in five steps from 0
to 35 MPa (fluid pressure range of more than 70% of Iranian oil reservoir rocks), and confining
pressure was selected from 0 to 40MPa (ranges of overburden pressures). Test results show rises
in specific energy with incremental increases in rock temperature, hydraulic pressure, and confining
pressure, while the rate of penetration decreases.
... The specific energy for sandstones increased from 6,369 to 27,081 J/cc when numbers of bursts were increased from 2 to 10, respectively. When relaxation time was increased from 0.5 to 1.5 seconds the specific energy of sandstones for three to five bursts increased from 7,323 to 10,240 J/cc [36]. Impact of relaxation time and spacing between laser spots on sandstone is shown in Figure 3. ...
... In the case of multiple spots for three bursts per shot the specific energy for sandstone increased from 6,450 to 8,638 J/cc when spacing was increased from 1.00 to 1.10 cm [34]. Effect of spot spacing and number of bursts per shot is shown in Figure 4. Generally specific energy for sandstone rock FIGURE 3 Effect of relaxation time and bursts per shot on specific energy of sandstone [36]. ...
... Several studies have addressed this issue earlier and recommended suitable laser focusing strategies [38][39]. FIGURE 4 Effect of spot spacing and bursts per shot on specific energy of sandstone [36]. ...
Natural oil, gas and coal reserves are limited in nature to which human access has become a major hurdle due to concrete reservoir rocks. Lasers have long been viewed as the ultimate holy-grail to drill through the solid rocks where conventional oil and gas bits fail to spall or grind the hard stones. Oil and gas industry has developed two and three cone diamond and turbo bits to spall and shear rocks to drill boreholes for oil, gas, geothermal and underground coal gasification projects but conventional methods often prove uneconomic and failure inflicting monetary and resource losses. This paper reviews the applications of laser technology in welding, drilling and spallation. Laser technology has also potential for igniting combustible fuel mixtures, wherein 60 to 70% developed fuels are wasted due to incomplete combustion. Global reserves can increase by increasing engine efficiency through complete combustion. Lasers have potential to help break solid rocks in borehole, improve fuels ignition and cause nuclear fusion to produce electricity. This paper also reviews several studies undertaken to measure Minimum Ignition Energy (MIE) of combustible fuels to develop suitable laser ignition system to replace conventional electric spark plugs. Laser spark plugs are expected to appear in market within next few years and laser fusion power plants after a few decades. This work reviews some earlier experimental results and reports some new initiatives to describe role of lasers in energy industry.
... High powered laser beams been widely applied in ablating or drilling materials [1]. As such, from 1997 onward, a group of scientists from Gas Technology Institute (GTI, formerly Gas Research Institute); Colorado School of Mines; Argonne National Laboratory, Parker Geosciences Consulting and LLC studied the feasibility of rock drilling and perforating oil and gas wells using high powered lasers [1]. ...
... High powered laser beams been widely applied in ablating or drilling materials [1]. As such, from 1997 onward, a group of scientists from Gas Technology Institute (GTI, formerly Gas Research Institute); Colorado School of Mines; Argonne National Laboratory, Parker Geosciences Consulting and LLC studied the feasibility of rock drilling and perforating oil and gas wells using high powered lasers [1]. They studied the specific energy (SE) of rocks like sandstone, shale and limestone and also studied the effects of pulsed laser irradiation [1]. ...
... As such, from 1997 onward, a group of scientists from Gas Technology Institute (GTI, formerly Gas Research Institute); Colorado School of Mines; Argonne National Laboratory, Parker Geosciences Consulting and LLC studied the feasibility of rock drilling and perforating oil and gas wells using high powered lasers [1]. They studied the specific energy (SE) of rocks like sandstone, shale and limestone and also studied the effects of pulsed laser irradiation [1]. ...
Laser perforating in oil and gas wells is a new scientific approach to the generation of
uniform holes at a selected pitch to increasing the permeability of rocks. The influence of
laser irradiation time and rock saturation by water and heavy oil on the specific energy, the
energy required to remove the unit weight of rock, used during Nd: YAG laser perforating.
The results show that an increase in the laser irradiation time increases the depth of the rock
hole as well as the specific energy used, with a nonlinear relationship. Here, the estimated ...
... High powered laser beams have been widely applied in ablating or drilling materials [1]. As such, from 1997 onward, a group of scientists from the Gas Technology Institute (GTI, formerly Gas Research Institute); Colorado School of Mines; Argonne National Laboratory, Parker Geosciences Consulting and LLC studied the feasibility of rock drilling and perforating oil and gas wells using high powered lasers [1]. ...
... High powered laser beams have been widely applied in ablating or drilling materials [1]. As such, from 1997 onward, a group of scientists from the Gas Technology Institute (GTI, formerly Gas Research Institute); Colorado School of Mines; Argonne National Laboratory, Parker Geosciences Consulting and LLC studied the feasibility of rock drilling and perforating oil and gas wells using high powered lasers [1]. One of the major problems in using laser perforation in practice is beam delivery to deep wells [2]. ...
Laser perforating is a new method in oil and gas wells where researchers look for an alternative to explosive methods. One of the important problems with this method is the generation of uniform and cylindrical holes at a selected pitch for enhancing the permeability of rocks. In non-moving laser perforation, the nozzle of the laser and the rock do not approach each other and due to laser convergence in a point, uniform and cylindrical holes are not created. For this reason, moving laser perforation is suggested in this research. One of the important parameters in moving laser perforation is the power of the laser that can be perforated at a specific rate. In this article we predicted the laser power for a definite rate of perforation (ROP) and then the accuracy of this prediction was evaluated to support the experiments. A pulsed Nd: YAG laser, with a pulse energy around 5.5 J, pulse repetition rate of 30 Hz and pulse duration of 2 ms were used for rock perforation in this study. The results shows that the presented relation for perforation could reliably be used in practice. Furthermore, by knowing the rate of perforation, the required laser power for consistent drilling could be calculated.
... To mitigate these sort of problems and increase the rate of penetration in time engineers invent new method of drilling and that is drilling with underbalanced condition [8]. Underbalanced drilling operation is a drilling condition in which hydrostatic head of mud column is maintained at a pressure less than that of fluid in the porous medium that known as pore pressure [7]. Further, the differences between pore pressure and drilling fluid pressure forces the wall which could release the fluid into the well, this kick is controlled and won't endanger the safety [2,11]. ...
... This being the case, the preservation of the high permeability fractures as the prime importance matter. So, if the benefits of UBD can be missed by the time concept, when pressure turns to overbalance suddenly and/or spontaneous imbibition [7,9].Spontaneous imbibition effect, which happens in low permeable reservoirs, caused by drilling fluid invasion (Graph -1, b). ...
In recent years, growing interest in underbalanced drilling has resulted in the rapid development of its
associated equipment technology, practices, and procedures. Underbalanced drilling is used to avoid
lost circulation, formation damage, Invasion of drilling fluid, which occurs in almost all the permeable
formations during drilling and decreasing weight on bit. However, the risk of wellbore collapse due to
lake of hydrostatic mud pressure is high. Therefore, using good geo-mechanical model may avoid
wellbore instability problem. In order to evaluate the potential for wellbore instability, it is necessary
to use elastoplastic model to compute the stresses and strains around the bore hole. Furthermore it
should be mentioned that the laser drilling process extremely depends on rock's geo-mechanical
properties. This paper describes a numerical investigation of wellbore instability in a fractured
carbonate reservoir and verified with reservoir core samples. Some necessary conditions should be
mentioned to gain the best method of comparison conventional UBD and laser UBD operations. It is
vital to evaluate the sensitivity of the wellbore stability by focusing on the effect of a laser irradiation
absorption. Finally, this paper fills the gap by paying attention to the sensitivity analysis and focuses
on assessing the influence of various drilling methods, rock properties and optical fluid parameters.
... One of the most famous reports of laser drilling and interactions between laser and rock was published by Dr. Moavenzadeh since 1967, that lasers could be effective in the case of excavating rock samples [5]- [7]. Some other research groups which are active in oil and gas industry, work on many projects about laser and rock interactions [2] [8] or using laser set ups to drill the oil and gas wells. Some of the famous professors and groups that work on these fields are, Dr. Graves, Dr. Gahan, Mr. Parker and the Gas Technology Institute [8]- [17]. ...
... Some other research groups which are active in oil and gas industry, work on many projects about laser and rock interactions [2] [8] or using laser set ups to drill the oil and gas wells. Some of the famous professors and groups that work on these fields are, Dr. Graves, Dr. Gahan, Mr. Parker and the Gas Technology Institute [8]- [17]. ...
Laser rock spallation is a rock removal process that utilizes laser induced thermal stress to fracture and cause a break through the rock by creating small fragments before melting of the rock. In this paper we investigated the effects of CO 2 laser irradiation on limestone of Iran Sarvak formation. Since the limestone included heavy and light oil, we studied the amount of laser beam absorption by this oils for determining thermal fractured during the laser drilling laboratory process. In order to characterize this limestone spectrophotometry (from UV to NIR), scanning electron microscopy (SEM) have been used.
... Plasma Pulse Geo Drilling (PPGD) is a novel contactless drilling technology, which uses high-voltage electric pulses to break away the rock, without relying on mechanical abrasion (e.g., [5,[8][9][10][11][12][13][14][15][16][17][18][19]). Thus, PPGD is part of a class of new "contactless" drilling technologies, which also includes thermal spallation (e.g., [6,[20][21][22][23][24][25][26][27][28][29][30][31][32]) and water jet drilling (e.g., [33][34][35][36][37]) and laser drilling (e.g., [38][39][40][41][42][43]) to name only some. PPGD has been given various names in the literature, including Electropulse Drilling, Plasma Channel Drilling, and Electric Impulse Drilling. ...
Plasma Pulse Geo Drilling (PPGD) is a contact-less drilling technique, where an electric discharge across a rock sample causes the rock to fracture. Experimental results have shown PPGD drilling operations are successful if certain electrode spacings, pulse voltages, and pulse rise times are given. However, the underlying physics of the electric breakdown within the rock, which cause damage in the process, are still poorly understood. This study presents a novel methodology to numerically study plasma generation for electric pulses between 200 and 500 kV in rock pores with a width between 10 and 100 μm. We further investigate whether the pressure increase, induced by the plasma generation, is sufficient to cause rock fracturing, which is indicative of the onset of drilling success. We find that rock fracturing occurs in simulations with a 100 μm pore size and an imposed pulse voltage of approximately 400 kV. Furthermore, pulses with voltages lower than 400 kV induce damage near the electrodes, which expands from pulse to pulse, and eventually, rock fracturing occurs. Additionally, we find that the likelihood for fracturing increases with increasing pore voltage drop, which increases with pore size, electric pulse voltage, and rock effective relative permittivity while being inversely proportional to the rock porosity and pulse rise time.
... When the laser encounters the surface of the rock, laser shows the following reactions; beams are reflected, beams are distributed, beams are absorbed [6] . Various tests have shown that reflected, distributed and absorbed beams have low effect on the rock, in addition, the mechanism that results in spallation and eventually drilling rock is absorbing laser beams [7] . In rock, which have high heat transfer coefficient, using laser results in the evaporating crystal water with solution mineral materials at rock, expansion of rock and finally fractures made in the structure of the rock [1] . ...
Well perforation in well completion involves the puncturing of the casing of the wall and cement, then into the rock formation that is in the production zone to permit the formation fluid flow into the well. This paper/study presents results from the use of CO2 laser beam to drill the perforation path through reservoir rocks. The CO2 laser beam has the ability to be used in deep production zones using fiber optic cables. This paper juxtaposes the information gotten from the completion of a well using a conventional perforation gun and a well completed using a laser perforation technique. Laser perforation enhances the rock permeability unlike the typical method of explosive perforation, which reduces the permeability of the rock. The increase in the rock permeability of the rock will lead to the increase in the production rate of oil and gas.
... The spallation temperatures induced by flame jet heating was below 5200°C and no solid phase transitions were reported. Parker et al. (2003b) investigated the rock removal efficiency of the multiple laser beams by drilling large diameter holes in rocks using 1.6 MW Mid-infrared Advanced Chemical Laser (MIRACL). It was found that combination of several small illuminated spots created a larger hole. ...
Application of laser technology for drilling rock samples reduces mining costs because of its higher transmission capabilities providing an alternative to conventional drill bits and blasting techniques. This paper investigates the effect of laser drilling parameters such as laser power, frequency, assist gas pressure and piercing time on drilling characteristics of rock mineral samples such as limestone, shale and sandstone using 12 kW CO2 Laser. For limestone, minimum specific energy of 46.14 kJ/mm³ and maximum rate of penetration 15.14 mm/s was achieved at 1000 W laser power, 1 kHz frequency, 6 bar assist gas pressure and 0.1 s piercing time. For sandstone, minimum specific energy of 14.33 kJ/mm³ and maximum ROP of 57.46 mm/s was achieved at 1000 W, 1 kHz, 2 bar and 0.1 s. For shale, minimum specific energy of 8.13 kJ/mm³ and ROP of 45.05 mm/s was achieved at 300 W, 5 kHz, 2 bar and 0.1 s, based on Response Surface Methodology. Morphological studies were reported on the drilled rock samples.
... Upon contact of laser to surface of stone, laser shows the following reactions: beams are reflected, beams are distributed, beams are absorbed as resulted in experiments. Tests indicate that reflected, distributed and absorbed beams have low effect on stone, in fact mechanism that results in spallation and finally drilling rock, is absorbing laser beams as demonstrated in Parker et al (2003). Using laser in rock having high heat transfer coefficient results in evaporating accumulated crystal water with solution mineral materials at stone, expansion of stone and finally fractures made in structure of stone. ...
No other scientific discovery of the 20th century has been demonstrated with so many exciting applications as laser acronym for (Light Amplification by Stimulated Emission of Radiation). Lasers are employed over a wide range of applications from scientific research, biomedicine, and environmental sciences to industrial materials processing, microelectronics, avionics, and entertainment. Laser drilling tests showed that high power lasers have the ability of drilling good clean holes to a certain depth, at which point melting occurs and a layer of glassy phase forms. Additional laser energy either did little or created fractures due to a combination of the effects of reflecation loss from the glassy surface, heat release from the bottom edge, and poor purging. This paper will present study results on using a pulsed CO2 laser to drill through the given rock samples. Preliminary test shows that CO2 laser can drill the rock as efficiently as the other types of high power lasers and the permeability of the rock lased by pulsed CO2 laser beam increases up to 150% compared to non-lased rocks due to clay dehydration and microfractures induced by the high temperature gradient and phase transformation volume expansion generated in the rock while lasing.
Add to CartView Cart
... The first pattern may be chosen is hexagonal. Orthogonal arrangements either left too much area untouched by the laser or too much overlap, wasting laser energy [7]. Octagonal patterns gave better coverage, but require many more spot locations for the circular pattern (fig-4) [8]. ...
Due to constructive role of technology developments in petroleum industry and their affects in reducing the costs of drilling, it is necessary to use future technologies. One of these new progresses taking very effective role in drilling industry is to get use of laser in drilling processes. The aim of this paper is to categorize and represent the different study results and also to analysis the principle and advantages of laser drilling. Compared to prevalent drilling, laser drilling is capable to augment the efficiency of drilling and solve its problems such as increasing the rate of penetration, monitoring the bottom hole, diminishing equipment and drilling process, but faces some problems such as laser beam transference, cleaning the down hole. As a result, the benefits of laser drilling overcome the problems and it can be replaced or combined in bits in early future. in this paper we showed the result of using laser technology during drilling operation. Also, In this paper we experiments on changing wavelength transmitted during fracturing and drilling.
... Some other research groups which are active in oil and gas industry, works on many projects about laser and rock interactions [ 4,7] or using laser set ups to drill the oil and gas wells. Some of the famous professors and groups that work on these fields are, Dr. Graves, Dr. Gahan, Mr. Parker and the Gas Technology Institute [1, 5, 7, 20, 21, 22, 23, 24, 25, 26, and 27]. ...
Actually, after applying optimization techniques and design new drilling operation can save a considerable amount of time and cost. In this paper we investigated the effects of co 2 laser irradiation on limestone of Iran sarvak formation. Since the limestone included by heavy and light oil we studied the amount of laser beam absorption by this oils for determining Thermal fractured during the laser drilling laboratory process In order to characterize this limestone spectrophotometry (from UV to NIR) and scanning electron microscopy (SEM) have been used.
... The first pattern may be chosen is hexagonal. Orthogonal arrangements either left too much area untouched by the laser or too much overlap, wasting laser energy [7]. Octagonal patterns gave better coverage, but require many more spot locations for the circular pattern (fig-4) [8]. ...
... [5] (Figure 4). Tests indicate that reflected, distributed and absorbed beams have low effect on stone, in fact mechanism that results in spallation and finally drilling rock, is absorbing laser beams [6]. Using laser in rock having high heat transfer coefficient results in evaporating accumulated crystal water with solution mineral materials at stone, expansion of stone and finally fractures made in structure of stone. ...
Employing novel drilling, and tunneling methods are active area of study since 1930s. In the present report, an Experimental study of the thermal impact of laser and plasma torch on carbonated rocks as part of thermal assisted drilling operation is presented. The experimental findings are then evaluated and verified by the Kirch's equations for stresses and strains around a cylindrical borehole. Since it is vital to carefully studying the wellbore stability in this type of drilling method, especially if it is associated with underbalanced drilling (UBD) and or Managed pressure drilling (MPD), further numerical investigations are carried out to highlight the necessary considerations in this regard.
Extremely hard and abrasive rocks pose great challenges to the past and ongoing TBM projects by increasing cutter wear and reducing penetration rates. A considerable amount of research has been conducted to improve the performance of TBMs in those challenging grounds by either improving the capacity of TBMs or developing assisting rock breakage methods. This paper first highlights the challenges of hard and abrasive rocks on TBM tunneling through case studies. It then presents the development of hard rock TBMs and reviews the technologies that can be used individually or as assistance to mechanical excavators to break hard rocks. Emphases are placed on technologies of high pressure waterjet, laser and microwave. The state of the art of field and laboratory research, problems and research directions of those technologies are discussed. The assisting methods are technically feasible; however, the main challenges of using those methods in the field are that the energy consumption can be over 10 times high and that the existing equipments have robustness problems. More research should be conducted to study the overall energy consumption using TBMs and the assisting methods. Pulsed waterjet, laser and microwave technologies should also be developed to make the assistance economically viable.
Lasers have potential for rock destruction applications in mining, petroleum, tunneling, and trenching. The high temperatures induced using high power lasers cause an increase in porosity and permeability, while reducing rock strength making it easier to break-up rocks. These results are part of a more extensive research project studying the application of laser technology in the oil and gas industry. Pre-and post-lasing analysis included mineralogy determination, clay characterization and original fractures, as well as porosity, permeability, elastic moduli and strength. The characteristics of unlased rocks were compared to the characteristics of lased rocks in order to determine the effect the high temperature caused by lasers has on altering the rocks. Over 300 core samples where exposed to laser energy in laboratory settings. Rocks types lased include Berea sandstone, shaley sandstone, limestone, concrete, granite, and salt. Permeability and porosity of the reservoir rocks ranged from 0.02 to 6000 md and 2% to 23%, respectively. It was found that high temperature caused by lasers enhance porosity and permeability because high temperature vaporizes or breaks cementation leading to more pore space. On the other hand, the strength of the rock was reduced as a function of temperature. The changes are related to the thermal properties of the rocks. For example, sandstones that have a comparatively high thermal conductivity have a wide range of temperature distribution and therefore higher permeability distribution.
Because of reducing drilling costs in an environmentally sensitive manner is critical we decide to initiate a three years study discussed in this paper had the goals of determine effect of several type of the fluids under atmospheric conditions by saturated or submerged samples, downhole pressure and temperature, and rock structure on laser-rock interaction. Sample of Sandstone, Limestone, and Shale were prepared for laser beam interaction experiment with a High Power Fiber Laser to determine how the beam’s size, power, exposure time, and downhole conditions can be effect on the amount of energy transferred to the rock for purpose of rock drilling. The current study indicated that the HPFL represent a technology that is more economize effective to operate, capable of remote operations, and require considerably less maintenance and repair. In addition to, team was interested in determining the behavior of water in the pores of the sandstones and other rocks.
The capability level of rotary as well as first generation drilling operation could not be matched for deeply drilling programs. To reach that deep, the increasing in drill string length could also cause an additional constraint on hydraulic performance. The operation of slim hole drilling has significant potential to reduce well costs. This cost might be savings are especially important with increased demand for reduced capital finance under current economic conditions in the Iranian oil and gas industry.
This savings achievement could be caused by use of smaller drilling rigs, work over rigs, reduced casing size, reducing requirement for drilling consumables and other costs associated with hole size. Otherwise, using laser irradiation for drilling operation can save cost little more higher look like do not using casing and perforation in reservoir layer for slim hole which are drilled by high power laser systems.
As the matter of fact, Cost savings achieved from slim hole drilling could be offset by inability to effectively transmit the weight to the bit, increased mechanical failures of drill pipes and tools and reduced the well bore instability effects in particular, in drilling operation at greater depths This paper investigates the effects of borehole parameters during laser drilling operations in the case of slim hole.
Introduction
For last 30 years old experiments and studies had shown laser drilling as benefit technical operation[27]. The earliest studies were resulting enhancing tunneling machines to be used to mining industry improved by lasers tools[21][22]. Lasers start works on industry with very low power but produced large wavelengths and it wasn't safe for industrial use The old methods of Drilling was the Rotary operation and drilling industry was developing[1][6].
Since the rotary drilling superseded cable tools drilling, there was a huge break for the oil industry when cable tool drilling had been replaced to the rotary drilling[18]. Developing started almost a century earlier, the basic method of using them was to reach gas and oil reservoir in our formations[24]. The current drill bits are very widely used tool for rough layer and drilled them in non-metallic goods in general and in step by step based products in regular. It's most widespread use is encountered in the home construction industry, really weak on the case for plumbing and electrical installations[23].
High power lasers can weaken, spall, melt and vaporize natural earth materials with thermal spallation being the most energy efficient rock removal mechanism.The most interesting focus of recent laser rock drilling research is on developing a laser rock spallation technique to drill large and deep holes in rocks, a potential application in gas and oil well drilling having a rock removal rate higher than that of conventional rotary drilling as well as that of flame-jet spallation.Research is also focused on using laser rock spallation to make perforation channels with improved permeability of the perforated rocks.However, laser rock spallation is a very complex phenomenon that depends on many factors.Fundamental understanding of this complex phenomenon is crucial to the success of its application to the petroleum industry.
In this paper, we propose a combined approach to this complex problem, that is establishing models for each of the physical phenomena based on the finite difference method (FDM), then combining them into one numerical procedure using the Combined Unified Procedure (C-CUP) method.With this approach, the transient temperature and stress distributions in dry or water-saturated rocks exposed to a laser beam have been calculated.The spallation boundary and rock removal efficiency have been determined for different laser conditions.The modeling results provide a better understanding of laser rock spallation phenomenon and most importantly, guidelines for selecting processing parameters for fast rock removal.
High power carbon dioxide lasers have successfully been used in drilling or cutting engineering materials such as metals, polymers and ceramics over the years. Can a carbon dioxide laser be used to efficiently drill different rocks in a deep gas well? Research sponsored by US Department of Energy has been carried out to answer this question. This paper will report the study results of using a super-pulsed COâ laser beam to drill rocks. A 6 kW COâ laser operated at superpulse mode was used to carry out the tests. Both linear tracks and deep holes were produced on the rocks. The energy required to remove a unit volume of rock, specific energy, was determined. Test results show that superpulsed COâ laser beam can be efficiently used to drill deep, large diameter holes in petroleum rocks with the assistance of purging gas.
High powered laser rock drilling was studied as a revolutionary method for drilling and completing deep gas and oil wells. The objectives of this 2002 to 2003 fiscal year research were to study the concept that large diameter holes can be created by multiple overlapping small beam spots, to determine the ability of lasers to drill rock submerged to some depth in water, to demonstrate the possibilities of lasers for perforating application, and to determine the wavelength effects on rock removal. Laser technology applied to well drilling and completion operations is attractive because it has the potential to reduce drilling time, create a ceramic lining that may eliminate the need for steel casing, provide additional monitor-on-drilling laser sensors and improve well performance through improved perforation. The results from this research will help engineering design on a laser-based well drilling system.
Samples of sandstone, limestone, and shale were prepared for laser beam interaction with a 1.6 kW pulsed Nd:YAG laser beam to determine how the beam's size, power, repetition rate, pulse width, exposure time and energy can affect the amount of energy transferred to the rock for the purposes of spallation, melting and vaporization. The purpose of the laser rock interaction experiment was to determine the threshold parameters required to remove a maximum rock volume from the samples while minimizing energy input.
Absorption of radiant energy from the laser beam gives rise to the thermal energy transfer required for the destruction and removal of the rock matrix. Results from the tests indicate that each rock type has a set of optimal laser parameters to minimize specific energy values as observed in a set of linear track and spot tests.
In addition, it was observed that the rates of heat diffusion in rocks are easily and quickly overrun by absorbed energy transfer rates from the laser beam to the rock. As absorbed energy outpaces heat diffusion by the rock matrix, local temperatures rise to the minerals’ melting points and quickly increase SE values. The lowest specific energy values are obtained in the spalling zone just prior to the onset of melting.
Samples of sandstone, shale, and limestone were prepared for laser beam interaction with a 1.6 kW pulsed Nd:yttrium-aluminum-garnet (YAG) laser beam to determine how the beam size, power, repetition rate, pulse width, exposure time, and energy can affect the amount of energy transferred to the rock for the purposes of spallation, melting and vaporization. As laser power increased, two rock removal zones, spallation and melting, were identified in the shale sample data with the least required SE of 0.508 kJ/cm3 occurring at the point prior to melting.
This paper describes the experimental results of selective rock removal using different types of high power lasers. US military owned continuous wave laser systems such as MIRACL and COIL with maximum powers of 1.2 MW and 10 kW and wavelengths of 3.8 and 1.3 mm respectively, were first used on a series of rock types to demonstrate their capabilities as a drilling tool for petroleum exploitation purposes. It was found that the power deposited by such lasers was enough to drill at speeds much faster than conventional drilling. In order to sample the response of the rocks to the laser action at shorter wavelengths, another set of rock samples was exposed to the interaction of the more commercially available high power pulsed Nd:YAG laser. To isolate the effects of the laser discharge properties on the rock removal efficiency, a versatile 1.6 kW Nd:YAG laser capable of providing pulses between 0.1 millisec and 10 millisec in width, with a maximum peak power of 32 kW and a variable repetition rate between 25 and 800 pulses/sec was chosen. With this choice of parameters, rock vaporization and melting were emphasized while at the same time minimizing the effects of plasma shielding. Measurements were performed on samples of sandstone, shale, and limestone. It was found that each rock type requires a specific set of laser parameters to minimize the average laser energy required to remove a unit volume of rock. It was also found that the melted material is significantly reduced in water saturated rocks while the drilling speed is still kept higher than conventional drilling.
The optimal use of lasers requires the understanding of the primary parameters pertinent to laser beam-material interactions. Basically, the laser beam is a heat source that can be controlled to deliver a wide range in intensities and power. When interacting with a material, reflection at the surface, and transmission and absorption through the material occur. The material interaction process is governed by the irradiance (power/unit area) of the incident beam and the interaction time resulting in an amount of heat/energy applied to the material per unit area. The laser beam is a flexible heat source where its intensity and interaction with materials can be controlled by varying the power and size of the beam or the interaction time. For any material, a minimum amount of energy has to be absorbed for the material to be ablated by the laser beam, i.e., a solid has to be heated to liquefy and then vaporize. Under certain conditions, the photon energy may be able to break the molecular bonds of the material directly. In general, the energy absorbed is needed to vaporize the material and account for any heat that may be conducted away. Consequently, the interaction is a heat transfer problem. The relevant parameters are the heat flux and total heat input to the material. The corresponding parameters for the laser beam- material interaction are the irradiance of the beam and the interaction time. The product of these two parameters is the energy applied per unit area. A high irradiance beam may be able to ablate a material rapidly without significant heat transfer to surrounding areas. For drilling or cutting materials, a high intensity beam is required for laser ablation with minimal heat lost to the surrounding areas. However, at high beam irradiance (>1 GW cm{sup -2} for Nd:YAG beams), plasma formed from ionization of gases and vapor will partially absorb or diffract the beam. Reduced penetration of the material results. Similarly, in welding using CO2 lasers where the beam irradiance is {approx}1 MW cm{sup -2}, the plasma plume formed decreases penetration. A high velocity jet of inert gas is usually used to blow away the plasma.
Specific Energy For Laser Removal Of Rocks, Laser Inst. of America The 20th International Congress on Applications of Lasers & Electro-Optics
- Z Xu
- G Kornecki
- C B Reed
- B C Gahan
- R A Parker
- S Batarseh
- R M Graves
Lasers and Beam Delivery for Rock Drilling
- K H Leong
- Z Xu
- C B Reed
Laser-Assisted Well Drilling
- Z Xu
- C B Reed
- G Kornecki
Laser Rock Drilling For Oil And Gas Wells, to be presented at AAPG 2003 Mid-Continent Section Meeting
- C B Reed
- Z Xu