Natural Gas and Oil Horizontal Drilling Technology - Thesis Example

Natural Gas and Oil Horizontal Drilling Technology Introduction The utilization of horizontal drilling technology in areas such as oil exploration, development and production experienced substantial growth in the last century. This growth has been particularly notable in the last five years. Horizontal drilling attained commercial viability in the late 1980s. The technology continues to enjoy massive success, especially in the North Dakota Bakken Shale and Texas’ Austin Chalk (Aguilera et al. 112). These projects promoted the testing of horizontal drilling in other domestic geographic areas and geologic situations. There are three notable categories of horizontal drilling, namely short, medium and long radius drilling. However, most oil producing companies appear to prefer the medium radius drilling technology. The increased popularity of horizontal drilling led to substantive growths in the achievable length of horizontal boreholes. Currently, horizontal displacements can extend to more than 8,000 feet. On the other hand, technicians have been unable to demonstrate the commercial feasibility of horizontal drilling and wells used in the production of natural gas, although several horizontal wells have previously been used in the production of coal seam gas. This paper will examine the horizontal drilling technology, which emerged after the vertical drilling technology became obsolete. Horizontal drilling is a significant technological advancement that enables the exploration of reserves’ previously unobtainable resources. Horizontal Drilling and its Technical Objectives An accepted description of what constitutes horizontal drilling has not been written. However, the following is a notable definition that combines the vital components of two noteworthy published definitions: horizontal drilling refers to a process of drilling and implementing, for the purpose of production, a well, which starts as a vertical linear bore, which extends from the earth surface to a sub layer location above the oil or gas reservoir (U. S. Environmental Protection Agency 6). This target is referred to as the kickoff point, and the extension bears off a curve to traverse the reservoir at the well’s entry point. Thereafter, the arch continues at an almost horizontal attitude tangent to the curve to remain in the reservoir partially or wholly till the required bottom hole location is attained. The mechanical purpose of horizontal drilling is to uncover significantly additional reservoir rocks to a well bore surface than attainable through drilling traditional vertical wells. The technical desire to attain this goal emanates from the deliberate attainment of other, more significant technical intentions related to the physical features of the reservoir in question. These physical features are essential in the consideration of a reservoir’s viability since they provide the project’s economic benefits. Notable examples of these technical aims include the desire to intersect numerous fracture systems within a single reservoir, as well as the requisite to deter the incident of unnecessarily premature gas or water intrusion (U. S. Environmental Protection Agency 10). This is because such premature intrusion can interfere with the production of oil. In these instances, the most prominent economic benefit of horizontal drilling is increased in the reservoir’s productivity. In the latter instance, another prominent economic advantage is the prolongation of the reservoir’s commercial life. In addition to reaching previously unobtainable gas and oil resources, horizontal drilling also possesses the following characteristics: cost premium and viable compensating benefits. With regard to the cost premium, the attainment of required technical objects through horizontal drilling comes at a high price. Horizontal drilling wells are between 25 and 300% more expensive to drill and complete than vertical wells aimed at a similar target horizon (Aguilera et al. 41). However, the differences in costs primarily stem from the fact that horizontal wells utilize highly specialized technologies and engineering practices in drilling. With regard to the desired compensating benefits, the fiscal benefits of successful horizontal drilling are partially offset by the increasing well costs prior to the onset of the project. Conventional Vertical Drilling For several decades, the only way oil explorers could extract natural gas or oil was to drill a vertical well into the earth. However, this method proved rather impractical in terms of economic impracticality or overall inefficiency (Charles Machine Works, Inc. 71). However, with the advent of technological advances, oil and gas explorers are able to deviate effectively from a straight line or vertical drilling and position the drilling equipment effectively to reach points that are not directly below the equipment’s point of entry. Vertical drilling entails a number of disadvantages, making the technology ineffective in the current age. Notably, most gas and oil reservoirs are more extremely larger with regard to their areal or horizontal dimensions than their vertical dimensions such as thickness. Therefore, through drilling the areal portion of a well that intersects a reservoir in a manner parallel to its plane of extensive dimension, horizontal drilling attains its initial technical objective. This objective deals with the exposure of extra reservoir rock on the wellbore surface than possible through vertically penetrating a reservoir in a perpendicular fashion. Traditional gas and oil drilling entailed the primary use of vertical drilling technology, which deterred the achievement of the aforementioned objective. Vertical drilling could not avoid the expulsion of water or air during the oil exploration process. Prior to the introduction of horizontal drilling, vertical drilling was the primary gas and oil exploration technology. Notably, vertical drilling has a multitude of inherent weaknesses, but since it was the only technology available, oil and gas explorers had no alternative than to utilize the wanting technology. Vertical and horizontal drilling are quite dissimilar technologies utilized in the discovery and production of natural gas and oil properties (Aguilera et al. 112). Although horizontal drilling has gained a lot of popularity, vertical drilling also underwent a period of popularity and familiarity. Vertical drilling is a traditional technology which involves drilling a well vertically down into the earth till the drill bit reaches the level at which gas or oil formation occurs. After completing the well construction phase, oil and natural gas explorers begin producing gas or oil from the reservoir in the earth. Wells drilled vertically are less productive than horizontal wells since vertical drilling deters substantial contact with the reservoir’s formation. This results in diminished reserves, as well as production capacities, of oil and natural gas. Vertical drilling allows access to reserves located on small or stranded properties. The economic impact of vertical drilling is relatively low as vertical wells produce less than 10 times the capacity of horizontal wells. Vertical wells used in vertical drilling also cost at least ten times more than horizontal drilling. However, vertical drilling remains plausible in areas unsuitable for horizontal drilling. Essentially, vertical drilling is almost identical to shallow well drilling, where shallow wells are safely completed in commercial and residential districts and ecologically vulnerable regions such as near state game lands, public forests or state parks (Short 27). The small and quiet rigs used in vertical drilling are relatively fast and minimally invasive, thereby making vertical drilling suitable for drilling in the aforementioned sensitive regions. Vertical drilling used ancient technologies such as air pressure to eliminate the need for discarding toxic drilling mud. Engineering and Technology used for Horizontal Drilling Horizontal drilling currently encompasses two related technologies, namely coiled tubing in place of traditional drill pipe for drilling and well completion and slimhole drilling in place of conventional large diameter holes. Slimhole drilling is a modern technique used for accessing reservoirs located in mature fields, thereby significantly reducing waste volumes. Slimholes also reduce operational footprints as equipment used in slimhole drilling is relatively smaller than equipment used in conventional ventures. Consequently, the region cleared for drilling can be 9,000 square feet and mud holding pits at least 75% less than demanded in conventional operations (Charles Machine Works, Incorporation 93). On the other hand, coiled tubing technology is a cost effective solution used when drilling in underbalanced, extremely deviated and reentry wells. This technology has impressive benefits such as minimizing equipment footprints and minimizing drilling wastes. A standard coiled tubing layout demands a working space nearly half of the conventional workover hoist. Therefore, operators can easily restore the drilling site after completing their drilling operations. In addition, the effect of equipment mobilization experienced on the environment becomes relatively low. Slimhole and coiled tubing drilling ensures minimal disruptive and less noisy operations, thereby reducing the noise impact of drilling on humans and wildlife close to the well site. Furthermore, since coiled tubing utilizes a continuous pipe, most noises linked to conventional drilling pipes are eliminated. Effective insulation as well as the equipment’s small size further reduces the noise level during drilling and completion activities. For instance, the noise magnitude of a conventional rig of radius of 1,300 feet is 55 decibels, but the noise level of a coiled tubing unit at a similar distance is 40 decibels (27% less). The small dimension of coiled tubing drilling reduces fuel use as well as emissions of gaseous air pollutants. From the kickoff position to the entry point of the arched segment, operators use a hydraulic motor mounted on a bit to drill a horizontal well (Short 11). Operators can steer the hole around the arc from left to right and horizontal to vertical by orienting the drilling and motor’s bend forward without pipe rotation (slide drilling). The arched section often encompasses a radius of 300 to 500 feet. Horizontal Drilling’s Ability to Reach Previously Unobtainable Resources The application of horizontal drilling technology includes the drilling of fractured source rocks, conventional reservoirs, stratigraphic traps, coal beds and heterogeneous reservoirs. This drilling takes place with a view to produce the reservoirs’ methane content and boost the sites’ recovery factors. The technology also enhances heat and fluid injection wells with the view of boosting both recovery factors as well as production rates. Notable successes encompass numerous horizontal wells drilled into a fractured field in Austin Texas’ Giddings Field that led to the production of at least 2.5 to 7 times more shale than vertical wells. The capacity of horizontal drilling to attain its desired technical goals outweighs the cost incurred in its operation. Due to its high cost, horizontal drilling is currently utilized in scenarios where vertical drilling would be ineffective (Short 61). In oil reserves that have low matrix permeability all round, lack of gas lids and a distinguishable water drive, horizontal wells are able to reach previously unobtainable reserves. This is particularly the case when the reservoir rock exists on a horizontal plane or when water or gas can interfere with effective recovery. Notably, explorers and operators are able to develop reservoirs with a significantly low number of wells because all horizontal wells can drain massive volumes of the rock. This means that the technology allows operators to access certain volumes of reservoir rock previously unobtainable. The use of horizontal wells in horizontal drilling significantly delays the incident of production challenges that produce low natural gas or oil production rates, minimal recovery capacities, and premature abandonment of wells (Aguilera et al. 88). Such deterrence significantly enhances the recovery of natural gas or oil, even in regions previously unreachable by vertical drilling. In addition, having the well located in the producing formation in the course of horizontal drilling enables the operator to utilize reduced density drilling mud. As a consequence, horizontal drilling can also allow the well to produce oil or natural gas during the process of drilling. This deters extensive formation damage. In essence, since horizontal drilling deters the damaging of the formation rock, the technology allows operators to access and obtain extensive regions of the formation. Works Cited Aguilera, Roberto,  G. M. Cordell, G. W. Nicholl, J. S. Artindale, M. C. Ng., and G.A. Runions. Horizontal Wells: Formation Evaluation, Drilling, and Production, Including Heavy Oil Recovery. 9th ed. Texas: Gulf Publishing Company, 1991. Print. Charles Machine Works, Incorporation. The Green Book, Horizontal Directional Drilling Systems: A New Dimension for Remediation. CMW-950. Oklahoma: The Charles Machine Works, Incorporation, 1996. Print. Short, Jim A. Introduction to Directional and Horizontal Drilling. Oklahoma: Pennwell Corporation, 1993. Print. U. S. Environmental Protection Agency. Alternative Methods for Fluid Delivery and Recovery. EPA/625/R-94/003. Washington, D.C.: U.S. EPA Office of Research and Development, 1994. Print. Read More