Experimental Study of Effective Hole Cleaning Using "Sweeps" inHorizontal Wellbores

Abstract

Experimental Study of Effective Hole Cleaning Using "Sweeps" in Horizontal Wellbores Sandeep Gopal Valluri; Sandeep Gopal Valluri U. of Tulsa Search for other works by this author on: This Site Google Scholar Stefan Z. Miska; Stefan Z. Miska U. of Tulsa Search for other works by this author on: This Site Google Scholar Mengjiao Yu; Mengjiao Yu U. of Tulsa Search for other works by this author on: This Site Google Scholar Ramadan Mohammed Ahmed; Ramadan Mohammed Ahmed U. of Tulsa Search for other works by this author on: This Site Google Scholar Nicholas Takach Nicholas Takach Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA, September 2006. Paper Number: SPE-101220-MS https://doi.org/10.2118/101220-MS Published: September 24 2006 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Valluri, Sandeep Gopal, Miska, Stefan Z., Yu, Mengjiao, Ahmed, Ramadan Mohammed, and Nicholas Takach. "Experimental Study of Effective Hole Cleaning Using "Sweeps" in Horizontal Wellbores." Paper presented at the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA, September 2006. doi: https://doi.org/10.2118/101220-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Annual Technical Conference and Exhibition Search Advanced Search AbstractDrilling fluid "sweeps" are specific fluids specially formulated to transport cuttings that cannot be removed by ordinary drilling fluid circulation. There has been a lack of certainty of the "sweep" type selection in the field. Although they are in common use in vertical and deviated drilling operations, not much information is known regarding the use of "sweeps", especially in terms of "efficiency" of the "sweeps" and the specific hydraulics involved.The effect of rheology of the "sweep" fluid on "sweep efficiency" has been investigated under low pressure ambient temperature (LPAT) and elevated temperature elevated pressure (EPET) conditions. The LPAT tests were conducted on a 90-ft-long transparent test section that consists of an 8″ ID casing and 4.5″ OD drill pipe. To investigate the effect of temperature on the "sweep efficiency", EPET experiments were conducted under simulated downhole conditions. The University of Tulsa Advanced Cutting Transport Facility (ACTF) flow loop (73-ft-long test section with annular geometry of 5.76″ × 3.5″) was used to simulate downhole conditions. Three types of sweep tests were conducted with six drilling fluids that have different rheological parameters.LPAT test results are presented in terms of weight of cuttings removed from the annulus, measured cutting bed height and differential pressure. Results of EPET experiments are presented in terms of cuttings concentration in annulus and differential pressure.Through the rigorous experimental work conducted, it has been identified that within the test conditions "high viscosity" "sweeps" in the absence of drill pipe rotation proved to be ineffective in bed erosion and cuttings removal. In addition to a higher flow rate, low concentrations of polymer, i.e. "less viscous sweep" and drill pipe rotation greatly improve "sweep efficiency". Finally, recommendations are made for practical field operations.IntroductionThe ability of a drilling fluid to transport cuttings to the surface is generally referred to as "carrying capacity". From an engineering point of view, cuttings transport is dependent on well bore inclination; cuttings slip velocity, flow regime, rotary speed of the drill pipe, fluid rheology, fluid flow rate, rate of penetration, cuttings size and shape, wellbore geometry and other drilling parameters.Cuttings transport (hole cleaning) in highly deviated wellbores is more challenging and critical than in vertical wells. In inclined wells, the fluid velocity has a reduced vertical component that may not be sufficient to transport all the cuttings particles to the surface. In addition, the drill pipe is usually located on the low side of the wellbore and forces the majority of fluid to flow above the drill pipe. These conditions cause the formation of a "cuttings bed" on the low side of the wellbore. Inadequate hole cleaning can lead to costly drilling problems such as: stuck pipe, premature bit wear, slow drilling rate, formation fracturing and high torque and drag.Novel methods of controlling the formation of these "cuttings beds" have been proposed over the years, such as the addition of special drilling fluid additives (viscosifiers) that enhance the cuttings transport ability of the drilling fluid. Unfortunately these methods are not efficient in preventing the formation of a cuttings bed. At best they delay the buildup of cuttings beds but often cause additional problems.Drilling fluid sweeps are used in order to clean the borehole from cuttings that are not removed by ordinary drilling fluid circulation. The applications are done generally in vertical and deviated drilling operations. In highly inclined wells, drilling fluid sweeps can be used to provide additional lift to cuttings. Types of drilling fluid sweeps as documented by Hemphill et al.1are high viscosity, high density, low viscosity, or combinations of these depending on the applications.A number of studies2–4 have been conducted to investigate the effect of drilling fluid rheology on cuttings transport. These studies and others debated high viscosity versus low viscosity fluids and which rheological parameters are most useful for characterizing hole cleaning efficiency. Keywords: cuttings transport, drilling fluid management & disposal, drilling fluid chemistry, drillstring design, production control, drilling fluid selection and formulation, production monitoring, drilling fluids and materials, drilling fluid formulation, flow rate Subjects: Drillstring Design, Drilling Operations, Drilling Fluids and Materials, Well & Reservoir Surveillance and Monitoring, Drill pipe selection, Directional drilling, Drilling fluid selection and formulation (chemistry, properties), Drilling fluid management & disposal, Cuttings transport, Production logging This content is only available via PDF. 2006. Society of Petroleum Engineers You can access this article if you purchase or spend a download.