Experimental Study and Modelling of Barite Sag in Annular Flow
- Yahya Hashemian (Schlumberger) | Stefan Miska (University of Tulsa) | Mengjiao Yu (University of Tulsa) | Evren Mehmet Ozbayoglu (The University of Tulsa) | Nicholas Takach (University of Tulsa) | Brenton McLaury (The University of Tulsa)
- Document ID
- Society of Petroleum Engineers
- Journal of Canadian Petroleum Technology
- Publication Date
- November 2014
- Document Type
- Journal Paper
- 365 - 374
- 2014.Society of Petroleum Engineers
- non-Newtonian fluid, annular flow, barite sag, modelling, experimental study
- 3 in the last 30 days
- 372 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 10.00|
|SPE Non-Member Price:||USD 30.00|
The phenomenon of settlement of weighting-material particles in drilling fluid is known as barite sag, which can lead to a number of drilling problems including lost circulation, well-control difficulties, poor cementing operation, and stuck pipe. This study investigates barite sag, both experimentally and numerically, in the annulus under flow conditions. Settlement of the weighting materials is generally called barite sag because barite is the most popular weight material used in drilling industry. The experimental part of the study has been conducted using a flow loop with 35-ft-long annulus test section to investigate the effects of fluid velocity in annulus, annulus eccentricity, pipe rotation, and inclination angle on barite sag. Density of the flowing fluid is measured continuously using Coriolis densitometers at the inlet and outlet of the annular test section. The simulation part of this study is based on a proposed particle- tracking method called “particle-elimination technique.” In this method, falling and axial velocities of the solid particles are estimated to predict their travelling paths. Density of the flowing fluid is updated, taking into account the number of particles that become stationary by reaching the casing wall. To model the downward motion of the barite bed on an inclined bed, the analogy of falling film of a viscous liquid on an inclined plane is applied. Velocity of the falling barite bed is calculated on the basis of an apparent viscosity approximated by the experiments. Knowing the velocity of the moving bed, the mass rate of barite downstream of the bed, which goes back into the main flow stream, is calculated and a new density for the moving fluid is achieved. The numerical simulation is modified from laboratory scale to real wellbore dimensions to be used for practical drilling applications. Results of the tests indicate that the highest sag occurs at low annular velocities, low rotational speeds, and high inclination angles. Barite-sag reduction caused by decreasing the inclination angle continues until the inclination-angle values are approximately 60 degrees, after which it becomes insignificant. Another observation made from experimental results and simulation work is that as the circulation of the drilling fluid in the loop continues, the fluid density decreases until it reaches an equilibrium stage. The equilibrium stage occurs faster for lower inclination angles. Effects of annular velocity and inner-pipe rotational speed on barite sag are similar; however, they are different from the trend observed when the inclination angle changes. Eccentricity of a nonrotating inner pipe did not have a significant effect on barite sag. However, the effect of inner-pipe rotation on barite sag for an eccentric annulus is more significant than in the concentric case. Comparing the results of numerical simulation with the experimental study shows a good agreement. The proposed simulation approach in this study can be used for barite-sag predictions in the annulus. A good prediction of the barite sag can prevent hazardous situations and would help engineers in drilling wells to spend less money and time.
|File Size||2 MB||Number of Pages||10|
Acrivos, A., and Herbolzheimer, E. 1979. Enhanced Sedimentation in Settling Tanks with Inclined Walls. Journal of Fluid Mechanics 92 (3): 435-57. https:// dx.doi.org/10.1017/S0022112079000720.
Ahmed, R. 2005. Experimental Study and Modeling of Yield Power-Law Fluid Flow in Pipes and Annuli. TUDRP Advisory Board Meeting. Tulsa, Oklahoma: The University of Tulsa, (2005).
Azouz, I. 1994. Numerical Simulation of Laminar and Turbulent Flows of Wellbore Fluids in Annular Passages of Arbitrary Cross-Section. PhD dissertation, The University of Tulsa, Tulsa, Oklahoma. (1994).
Bern, P.A., Van Oort, E., Neusstadt, B. et al. 2000. Barite Sag: Measurement, Modelling and Management. SPE Drill & Compl 15 (01): 25–30. SPE-62051-PA. http://dx.doi.org/10.2118/62051-PA.
Bern, P.A., Zamora, M., Slater, K.S. et al. 1996. The Influence of Drilling Variables on Barite Sag. Presented at the SPE Annual Technical Conference and Exhibition, Denver, Colorado, 6-9 October. SPE-36670-MS. https://dx.doi.org/10.2118/36670-MS.
Bird, R.B., Stewart, W.E., and Lightfoot, E.N. 1960. Transport Phenomena. New York City, New York: John Wiley & Sons Publishing.
Bourgoyne, A. T., Millheim, K. K., Chenevert, M. E. et al. 1986. Applied Drilling Engineering, Vol. 2. Richardson, Texas: Textbook Series, Society of Petroleum Engineers.
Dye, W., Hemphill, T., Guster, W. et al. 1999. Correlation of Ultra-Low Shear Rate Viscosity and Dynamic Barite Sag in Invert-Emulsion Drilling Fluids. Presented at the SPE Annual Technical Conference and Exhibition, Houston, TX, 3-6 October. SPE-56636-MS. http://dx.doi.org/10.2118/56636-MS.
Hanson, P. M., Trigg, T. K., Rachal, G. et al. 1990. Investigation of Barite Sag in Weighted Drilling Fluids in Highly Deviated Wells. Presented at the SPE Annual Technical Conference and Exhibition, New Orleans, Louisiana, 23-26 September. SPE-20423-MS. http://dx.doi.org/10.2118/20423-MS.
Hemphill, T. and Ravi, K. 2006. Turning on Barite Sag with Drillpipe Rotation: Sometimes Surprises Are Really Not Surprises. Presented at the AADE 2006 Fluids Conference, Houston, Texas, 11-12 April.
Jamison, D.E. and Clements, W. R. 1990. A New Test Method to Characterize Setting/Sag Tendencies of Drilling Fluids in Extended Reach Drilling. Presented at the ASME 1990 Drilling Tech. Symp., PD 27, 109.
Jefferson, D.T. 1991. New Procedure Helps Monitor Sag in the Field. Presented at the Energy Sources Technology Conference, New Orleans, Louisiana. ASME 91-PET-3.
Kenny, P. 1996 Hole-Cleaning Capabilities of an Ester-Based Drilling Fluid System, SPE Drill & Compl 11 (1): 3-10. SPE-28308-PA. http://dx.doi.org/10.2118/28308-PA.
Nguyen, T. C., Mishka, S., Yu, M. et al. 2009. Predicting Dynamic Barite Sag in Newtonian Oil-Based Drilling Fluids. Presented at the 2009 SPE Annual Technical Conference and Exhibition, New Orleans, Louisiana. SPE-124137-MS. https://dx.doi.org/10.2118/124137-MS.
Paslay, P.R., Sathuvalli, U.B., and Payne, M. L. 2007. A Phenomenological Approach to Analysis of Barite Sad in Drilling Muds. Presented at the 2007 SPE Annual Technical Conference and Exhibition, Anaheim, California, 11-14 November. SPE-110404-MS. https:// dx.doi.org/10.2118/110404-MS.
Saasen, A., Liu, D. and Marken, C.D. 1995. Prediction of Barite Sag Potential of Drilling Fluids from Rheological Measurements. Presented at the SPE/IADC Drilling Conference, Amsterdam, Netherlands, 28 February-2 March. SPE 29410. https://dx.doi.org/10.2118/29410-MS.
Saasen, A., Marken, C., Sterri, N. et al. 1991. Monitoring of Barit Sag Important in Deviated Drilling. Oil & Gas Journal 89 (34).
Shah, S., El Fadili, Y. and Chhabra, R. P. 2007. New Model for Single Spherical Particle Settling Velocity in Power Law (Visco-Inelastic) Fluids. International Journal of Multiphase Flow 33 (1): 51-66. https://dx.doi.org/10.1016/j.ijmultiphaseflow.2006.06.006.
Zamora, M. 2009. Mechanisms, Measurement and Mitigation of Barite Sag. Presented at the Offshore Mediterranean Conference and Exhibition, Ravenna, Italy: Offshore Mediterranean Conference, 25-27 March. OMC-2009-105.