Field Validation of Drillpipe Rotation Effects on Equivalent CirculatingDensity

Abstract

Field Validation of Drillpipe Rotation Effects on Equivalent Circulating Density Terry Hemphill; Terry Hemphill Halliburton Energy Services Group Search for other works by this author on: This Site Google Scholar Peter Anthony Bern; Peter Anthony Bern BP Research Search for other works by this author on: This Site Google Scholar Juan Rojas; Juan Rojas BP USA Search for other works by this author on: This Site Google Scholar Krishna Ravi Krishna Ravi Halliburton Energy Services Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Annual Technical Conference and Exhibition, Anaheim, California, U.S.A., November 2007. Paper Number: SPE-110470-MS https://doi.org/10.2118/110470-MS Published: November 11 2007 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Hemphill, Terry, Bern, Peter Anthony, Rojas, Juan, and Krishna Ravi. "Field Validation of Drillpipe Rotation Effects on Equivalent Circulating Density." Paper presented at the SPE Annual Technical Conference and Exhibition, Anaheim, California, U.S.A., November 2007. doi: https://doi.org/10.2118/110470-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 AbstractIt is important to predict the Equivalent Circulating Density (ECD) of fluids as closely as possible for safe drilling and completion of wells. This is especially true for those challenging wells where the margin between hole collapse and formation fracturing is very narrow. These characteristics of narrow safe drilling windows are commonly seen in extended-reach drilling (ERD) and deepwater wells, and pose significant drilling and cementing challenges.Over recent years, the changes in ECD caused by fluid compressibility, downhole fluid rheology, drillpipe eccentricity, and rate of penetration have been widely studied. In contrast, work on the modeling of drillpipe rotation effects on pressure drop and ECD have received relatively little attention. Early studies have looked at the relationship between circulating pressure drop, especially in slimhole drilling configurations, and at very high drillpipe rotational speeds. More recently the predicted effects of rotation on ECD in concentric and eccentric wellbore geometries have been studied and model improvements have been made. These technical approaches are summarized in this paper.The effect of drillpipe rotational speed on the predicted ECD for different drillstring combinations are presented and discussed. The calculated effects of drillpipe rotation on pressure drop and ECD are compared to actual field measurements using downhole annular pressure gauges.From the results discussed in this paper, the reader can gauge the accuracy of the current calculation methods. The changes in ECD with drillpipe rotation can now be better predicted, something especially important for those wells whose safe drilling window is narrow. Ultimately this reduces drilling and completions risk and helps assure safe and efficient well construction.IntroductionMany studies on the effects of drillpipe rotation on annular drilling hydraulics have been performed over the years1,2,3. In these studies, the authors have looked at hydraulic effects in terms of changes in annular pressure drop (?P). They generally concluded that annular pressure initially drops with increasing drillpipe rotation speed, and later increases with increasing drillpipe rotation speed. In slim hole drilling studies4,5,6, it was found that a rotating drillpipe can produce large increases in annular pressure drop when annular clearances are small. Later, with the advent of downhole pressure drilling tools, researchers7,8,9 found that there was indeed a positive link between drillpipe rotation speed and Equivalent Circulating Density (ECD), a term that mathematically combines Equivalent Static Density (ESD) and annular pressure drop converted to density by the following equation:ECD*=*ESD*+*?P/0.052/TVD(1)Figure 1 and Figure 2 show results from published work8,9 that clearly demonstrate a relationship between drillpipe rotation speed and increasing ECD. Figure 1 shows data for a 12.25-in section, while Figure 2 contains data for 8.75-in and 8.5-in sections. In presenting the data, the authors did not publish a model to account for the measured changes in ECD.Today, researchers now generally agree that there is a positive relationship between drillpipe rotation speed and annular pressure drop / ECD. Until recently there has not been published a comprehensive mathematical model that accurately predicts the effects of drillpipe rotation on annular pressure drop / ECD. Results using a preliminary model10 were published for concentric wellbores, and subsequently results for a more comprehensive model11 were published for eccentric wellbores.Studies of drillpipe rotation effects in circulating invert emulsion drilling fluids were made, and the combined effects on ECD were measured. In these "fingerprinting" exercises performed on a North Sea deviated well, key operational and drilling fluid parameters were recorded and the subsequent ECD measurements were measured and recorded. This body of work represents the most comprehensive set of data from which to study the effects of drillpipe rotation on annular pressure changes. In this paper, the data set from the North Sea experiments is used to validate the mathematical model constructed for drillpipe rotational effects in concentric and eccentric wellbores. Keywords: well control, annular pressure drilling, flow rate, drilling fluids and materials, Upstream Oil & Gas, pressure drop, ECD, drillpipe rotation speed, drilling operation, drillpipe eccentricity Subjects: Drillstring Design, Drilling Operations, Pressure Management, Drilling Fluids and Materials, Drill pipe selection, Well control This content is only available via PDF. 2007. Society of Petroleum Engineers You can access this article if you purchase or spend a download.