Correlation of Ultra-low Shear Rate Viscosity and Dynamic Barite Sag in Invert-Emulsion Drilling Fluids

Dye, William; Hemphill, Terry; Gusler, William; Mullen, Gregory

doi:10.2118/56636-ms

Cited by 22 publications

(3 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At annular velocities greater than 100 ft/min, the "magnitude of dynamic sag" is small compared with lower annular velocities. The highest sag occurs at an annular velocity of 40 ft/min (Dye et al 1999).…”

Section: Introductionmentioning

confidence: 96%

Experimental Study and Modelling of Barite Sag in Annular Flow

Adariani

2014

Journal of Canadian Petroleum Technology

View full text Add to dashboard Cite

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 , 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...

show abstract

Section: Introductionmentioning

confidence: 96%

Experimental Study and Modelling of Barite Sag in Annular Flow

Adariani

2014

Journal of Canadian Petroleum Technology

View full text Add to dashboard Cite

show abstract

“…13,14 This instrument is an improvement over conventional 6-speed viscometers because of several unique features:1) measuring capabilities at ultra-low shear rates, 2) separation of drive and measuring systems and 3) utilization of a computer acquisition system to record, store and analyze data accuracy.…”

Section: Field Applicationsmentioning

confidence: 99%

Development Process and Field Applications of a New Ester-Based Mud System for ERD Wells on Australia's Northwest Shelf

Eckhout

Dolan

Gogan

et al. 2000

IADC/SPE Asia Pacific Drilling Technology

Self Cite

View full text Add to dashboard Cite

fax 01-972-952-9435. AbstractExtended reach wells drilled from the Goodwyn Alpha platform are highly aggressive and have been drilled with a variety of invert-emulsion mud systems. Historically, mud system selection for these wells was based on compliance to environmental regulations and satisfaction of technical criteria. In order to take a more proactive approach to mud system selection and to raise environmental standards to new levels, an initiative was undertaken to replace the environmentally acceptable, and technically competent mud system being used on Goodwyn with a new ester-based system. Ester-based mud systems are considered the "systemof-choice" in terms of environmental acceptability and possess inherent lubricating qualities for torque and drag reduction. This paper describes the development process and 4 successful field applications of the new ester-based mud system. A new ester, which exhibits the lowest kinematic viscosity of commercially available esters, was identified and selected for use. New and innovative technologies were introduced in the laboratory development and field applications to address barite sag, hole cleaning efficiency and hydrolytic stability.The system development and field testing processes were enhanced by daily communication with the development teams in Aberdeen, Houston and Perth. Down-hole friction factors were significantly lower than modeled predictions. Barite sag problems encountered on previous wells were eliminated, and hole cleaning efficiency was optimized.

show abstract

“…The solid particles settling is a common issue encountered in high-pressure high-temperature (HPHT) conditions where downhole temperature is greater than 300 °F in both vertical and deviated wells and known as solids sag. − This sagging issue is affected by the drilling fluid properties such as the low viscosity, fragile gel strength, low linear viscoelastic, solid particles characteristics, and drilling parameters, and it may eventually result in wellbore instability, stuck pipes, and loss of circulation due to the wide variation in mud properties. − The sagging issue becomes more serious at an inclination angle above 30°, and the maximum sagging was observed to occur in the range of 45 to 60° wellbore inclination. ,, …”

Section: Introductionmentioning

confidence: 99%

Enhancing Hematite-Based Invert Emulsion Mud Stability at High-Pressure High-Temperature Wells

et al. 2020

View full text Add to dashboard Cite

Drilling fluids have a crucial continued role in drilling a successful well; however, most of the drilling technical and operational challenges are incorporated with the drilling mud stability and properties. The solid particles settling in drilling mud that deteriorates its stability is a common issue encountered in high-pressure high-temperature (HPHT) conditions. This issue, known as solids sagging, may eventually result in stuck pipes, wellbore instability, and loss of circulation. The objective of this work is to introduce garamite to enhance the stability of hematite-based invert emulsion mud under HPHT situations. The used garamite and hematite weighting material were analyzed using X-ray fluorescence, scanning electron microscopy, and particle size distribution to identify their compositions, morphologies, and particle sizes. The effects of adding different concentrations of garamite (0.5, 1.0, 1.25, and 1.5 g) to the field formula of hematite-based invert emulsion mud were investigated. The mud density, stability, sagging tendency, rheology, viscoelasticity, and filtration properties were studied to formulate a stabilized and distinguished-performance drilling mud. The obtained results indicated that garamite did not change the mud density while enhancing the emulsion stability by increasing the electrical stability proportionally with the added garamite quantity. The sagging experiments showed that adding 1.25 g of garamite is sufficient to prevent the sagging problem in both static and dynamic conditions as it was enough to enforce the sag parameters into the safe range of sag performance indicators. This 1.25 g of garamite improved the yield point by 152% from 19 to 48 lb./100 ft 2 with a slight increase in plastic viscosity from 14 cP for base mud to 18 cP and significant increase in the gelling strength and viscoelastic properties. Adding 1.25 g of garamite showed a slight enhancement in the filtration properties as the filtrate volume was reduced by 8% from 3.7 to 3.4 cm 3 and the filter cake thickness has 16% reduction from 2.69 to 2.26 mm. As a result, a mud with distinguished performance, in terms of rheology, suspension, sag performance, and stability, was obtained. Hence, a basis for safely drilling the HPHT formations was delivered, which reduces the drilling cost by minimizing the nonproductive time.

show abstract

Correlation of Ultra-low Shear Rate Viscosity and Dynamic Barite Sag in Invert-Emulsion Drilling Fluids

Abstract: This paper was prepared for presentation at the 1999 SPE Annual Technical Conference and Exhibition held in Houston, Texas, 3–6 October 1999.

Cited by 22 publications

References 13 publications

Experimental Study and Modelling of Barite Sag in Annular Flow

Experimental Study and Modelling of Barite Sag in Annular Flow

Development Process and Field Applications of a New Ester-Based Mud System for ERD Wells on Australia's Northwest Shelf

Enhancing Hematite-Based Invert Emulsion Mud Stability at High-Pressure High-Temperature Wells

Contact Info

Product

Resources

About