Since the early twentieth century rotary drilling has revolutionized the procedure of extraction of crude oil replacing conventional methods like cable tool drilling. However with the advent of new technology it is time to look at future alternative, more efficient drilling methods. This paper acts as an eye opener to the feasibility of using laser drilling over modern currently used drilling techniques. The design and operation of a new laser-mechanical bit is put forth by the medium of this paper. This innovative bit shows probability of reducing rig time and increasing efficiency in drilling. The possible changes to be implemented in the present day drill string due to incorporation of this new bit is accounted for and an analysis of the possible advantages and disadvantages of this bit if implemented is also highlighted. Introduction Rotary drilling has been widely used for extraction, in most of the oil fields in various parts of the world for more than a century. During this period many alternatives drilling techniques have been suggested, worked upon and tried so as to reduce the time and increase the efficiency of drilling. These techniques include the use of niche technology with tools commonly known as novel devices. This category of devices includes Water jets, Electron Beams, Cavitating Jets, Electric arcs, Plasmas and Lasers to name a few. In comparison with all the above devices, laser drilling if developed has shown the potential to be a futuristic advanced tool that will revamp the conventional rotary drilling system. LASER basically is an acronym for Light Amplification by Stimulated Emission of Radiation. It is basically a device which converts energy in one form to electromagnetic radiation beams (photons). These photons are basically produced due to the returning of atoms to their lower energy state after their excitation to higher energy states. When this happens a photon is released. This high energy coherent light radiation can be focused to form intense high powered beams which can be used to fragment, melt or vaporize rocks depending on the input power, type of laser, adjusted focal length and interaction characteristics of the laser with the particular rock type. The other major laser parameters include discharge method (pulsed or continuous), wavelength, exposed time, pulse width, repetition rate, average power and peak power. These parameters determine the effective energy transfer to the rock. Lasers are currently being used as a potent tool with effective results, in various fields such as medical, metallurgical and for military applications. Currently lasers are widely used for precision cutting and welding of metals, ceramics and various other materials. Laser Drilling Majority of research in the field of laser drilling is focused on solely using a laser to vaporize the rock. These methods are proposed to have various advantages over currently used rotary drilling techniques which include:Increasing Rate of Penetration (ROP)-Laser drilling shows the potential of having ROPs that is more than 100 times the presently ROPsProvision of temporary casingReducing trip time and an increased bit life.Lesser dependence on parameters such as weight on bit, mud circulation rate, rotary speed and bit designAccurate and precise drilling since lasers travel in a straight line problems like dog legging are completely eliminated.Providing enhanced well control, perforating and side-tracking capabilitiesSingle diameter bore holeAchieving these breakthroughs with environmentally attractive, safe and cost effective technology1

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Sand Jet Perforation (SJP) is a process which uses a high velocity jet of abrasive sand laden fluid to cut through the casing, cement and into the formation jetting pressure and cutting time can be varied to achieve maximum penetration. The process begins by using Coiled Tubing to convey, accurately position and operate the sand jet perforating tool with integral casing collar locator (CCL). The sand jetting assembly perforates the zone; the CT is moved uphole to allow an optimum fracture treatment to be pumped down the casing/CT annulus. Based on the difference in depth of the perforation interval between the zones to be fractured, the underflush volume for fracturing treatment is calculated to place a sand plug in order to isolate the zone at the end of the treatment. If this is not sufficient, the sand used for perforating the next zone is allowed to settle to form additional plug height. An added advantage of using this technique includes washing off the extra sand (if any) using Coiled Tubing in the same run, which leads to saving significant amount of time and eliminates the need of setting up expensive packers to achieve zonal isolation in multi-zone wells. With conventional wireline perforations, about 12 to 15 zones were usually fractured in a month in the Raniganj Coal Bed Methane (CBM) Block, India. The application of the above technology, made it possible to fracture more than 38 zones in a month. The process ensured that each zone received a positive zonal isolation and optimized fracturing treatment leading to cost effective and quality fracturing treatments. This paper highlights the sand jetting perforation process for achieving maximum penetration, advantages of the technique for fracturing in CBM wells and the planning involved placing sand plugs for achieving optimized and economic stimulation treatment.

In stimulation application, currently available degradable fiber-laden viscoelastic self-diverting acids (FLVSDA) are limited to moderate reservoir temperatures due to the lack of fiber integrity and stability. The upper bound temperature for current fiber is limited by the rate of polymer hydrolysis, which results in inadequate stability and fast degradation in an aqueous environment. As reservoirs are being encountered with higher temperatures, there is an industry need to expand the technology application to higher temperature environment (up to 350°F) for enhanced diversion and leakoff control. A novel high-temperature degradable fiber (HTF) was developed with two distinct features. First, the modified polymer is used with a highly ordered structure, resulting in higher melting point and enhanced thermal and hydrolytic stability compared to contemporary mid-temperature fiber (MTF). Second, the morphology is crimped, which enables better material dispersion and plugging efficiency when designed with higher concentration. Comprehensive laboratory tests were conducted for degradation and stability comparison in neutral and acidic media to replicate real acid treatment conditions. Also, bridging tests in slot geometry were conducted to characterize the diversion efficiency of the fiber-laden slurries. Finally, the material was tested in fields with temperatures ranging from 290 to 330°F. Fiber integrity and stability differentiated the performance of HTF and MTF at temperatures higher than 275°F. The critical point of HTF performance was achieved after 6 hours of exposure at 290°F in 100% spent 15% HCl with a concentration of 175 lbm/1000 gal US, whereas MTF is stable for less than 2 hours under the same testing conditions. The HTF demonstrated similar enhanced diversion efficacy when tested in more antagonistic media such as 50% spent acid. Fiber mass loss is considered as a characteristic of fiber stability, and premature fiber degradation compromises diversion effectiveness. To confirm the correct fiber shape at the degradation point, scanning electron microscopy (SEM) was used, and HTF showed no change in original shape and diameter. Pressure response at bridging was used as an additional characteristic for relative comparison of bridging ability for different fibers in laboratory conditions. A total of eighteen-stage acid stimulation treatments were conducted in six HT horizontal and vertical wells in fracturing and matrix acidizing modes using 51 fiber-laden diverter pills where significantly boosted diversion was observed with novel morphology fiber. Consequently, up to 30% to 40% production enhancement was observed in the wells treated with HTF due to effective stimulation fluids diversion and stimulation across the entire net pay. The broad-spectrum of fit-for-purpose diverters plays a critical role in optimal treatment fluid distribution during acid stimulation treatments. Innovation in the material and morphology of the existing fiber portfolio adds essential value by allowing the wells to deliver higher production rates through improved diversion and optimum reservoir stimulation.

Proppant fracturing treatments in sandstone formations are routinely executed in Kuwait, however when carbonate formations are the target, acid fracturing is the preferred treatment method. It has been observed that acid fracturing delivers a high initial production however maintaining a sustainable production rate is a challenge in the tight cretaceous carbonate formations in Kuwait. A production enhancement technique needed to be identified in order to deliver more sustainable production and maximize recovery from these carbonate formations. Based on global experience it was proposed that proppant fracturing can deliver more sustainable production rate as compared to acid fracturing. Proppant fracturing had been previously attempted on two occasions in Kuwait, however both the attempts were evaluated as not being operationally successful. Hence prior to executing the first successful proppant fracturing treatment in carbonates in Kuwait a thorough study was undertaken to identify and mitigate the possible risks. The cretaceous carbonate formations in North Kuwait are relatively shallow and are known to be tight and highly ductile. Due to the ductility of these formations, proppant placement and reduction of the fracture conductivity due proppant embedment were thought to be significant risks. During the course of the project, detailed core analysis and testing was conducted using formation core samples to ascertain the severity of this risk. Successful execution of this hydraulic fracturing treatment was pivotal in order to plan the future production strategies from these formations. A cautious approach needed to be followed as proppant placement was of paramount importance. Different strategies were incorporated in the fracturing workflow to ensure the success of the treatment and to maximize data collection in order to optimize future treatments and well placement. Multiple mini-fracs, temperature logs and pumping of novel non-radioactive tracer proppant were some of the techniques utilized. During execution various decisions were taken real-time to ensure success of the treatment. It was observed that all parameters were consistent with the results of the core and laboratory testing conducted during the initial phase of the project which lead to optimizing the proppant placement. The success of this treatment has been a game changer resulting in more wells being identified as candidates for proppant fracturing in this field. Now that proppant placement has been established the objective of future treatments is to optimize fracture designs, fluids and treatment schedules which will help the future production enhancement strategy for this field. Lessons learnt from this first successful well will be applied to future wells planned in carbonate reservoirs in Kuwait, in order to maximize recovery.