Modeling of Laser Spallation Drilling of Rocks for Gas- and Oilwell Drilling

Field: Engineering (Physical Sciences)

Modeling of Laser Spallation Drilling of Rocks for Gas and Oil Well Drilling Zhiyue Xu; Zhiyue Xu Argonne National Lab Search for other works by this author on: This Site Google Scholar Yuichiro Yamashita; Yuichiro Yamashita Argonne National Lab Search for other works by this author on: This Site Google Scholar Claude Reed Claude Reed Argonne National Lab Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Annual Technical Conference and Exhibition, Dallas, Texas, October 2005. Paper Number: SPE-95746-MS https://doi.org/10.2118/95746-MS Published: October 09 2005 Connected Content Related to: Modeling Laser-Spallation Rock Drilling Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Xu, Zhiyue, Yamashita, Yuichiro, and Claude Reed. "Modeling of Laser Spallation Drilling of Rocks for Gas and Oil Well Drilling." Paper presented at the SPE Annual Technical Conference and Exhibition, Dallas, Texas, October 2005. doi: https://doi.org/10.2118/95746-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Annual Technical Conference and Exhibition Search Advanced Search AbstractHigh 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.1. IntroductionLaser rock spallation is a rock removal process that utilizes laser-induced thermal stress to fracture the rock into small fragments before melting of the rock occurs.High intensity laser energy, applied on a rock that normally has very low thermal conductivity, concentrates locally on the rock surface area and causes the local temperature to increase instantaneously. This results in a local thermal stress in subsurface that is enough to spall the rock.Previous test data shows that it is the laser rock spallation that removes reservoir rocks most energy efficiently among all laser rock removal mechanisms [1]. The advantages of the laser spallation rock removal are three-folds:rock is removed by spallation, so it is most energy efficient,the process is easy on beam fiber-optical cable delivery due to low required laser power for each spalling beam, andsmall rock debris or fragments are readily flushed out by standard well flushing method.In order to take advantage of the laser spallation, recent research and development work on applications of advanced high power lasers to drilling and completion of gas and oil wells mainly focuses on two fronts. The first is to develop a multi laser beam rock spallation technique to drill large and deep holes in rocks such as gas and oil wells with a rock removal rate higher than that of conventional rotary drilling as well as flame-jet spallation. In this approach, each laser beam spalls a hole as big as the beam spot and half beam size deep. Multiple such beams are overlapped to remove a layer of large rock area. Layer by layer, a large and deep hole is drilled [2, 3]. The second front is to develop a laser rock perforation technique for gas and oil well completion applications. Perforation of gas and oil wells requires creating a hole into a composite structure of steel casing, cement, and rock formation. Current explosive charge perforation method, while capable of creating the holes, significantly reduces permeability of the rock, and is reaching its technical limits. On the other hand, lab tests demonstrate that laser beams not only cut rocks efficiently, but also significantly increase the permeability of spalling-drilled rock [4]. An innovative laser perforation system will allow the gas and oil industry to rejuvenate injection and production rates quickly and easily. Keywords: drilling operation, efficiency, boundary, laser, transient behavior, pulsed laser beam, laser burst, laser beam, modeling, laser rock spallation Subjects: Drilling Operations, Well & Reservoir Surveillance and Monitoring, Formation Evaluation & Management This content is only available via PDF. 2005. Society of Petroleum Engineers You can access this article if you purchase or spend a download.