indicated that the highest sag occurs at low annular veloc-ities and rotational speed and, also, at high inclination angles. It was observed that at inclination angles less than 60 , for any annular velocity, barite sag is not signiﬁcant. In the present work, a study on the modeling of barite sag in drilling ﬂuids was performed. The emphasis
Further, barite settling can occur under static or circulating conditions, or under both, and is affected by mud density, rheological properties, temperature, hole angle, size of suspended solids, and other factors. Sag can be an offshoot of both unsuitable drilling fluid properties and …
AADE–02-DFWM-HO-12 New Technology to Manage Barite Sag 3 rpm, the shear rate between the outer rotating sleeve and inner bob is ≅ 170 s-1. Dynamic sag is quantified as the change in mud weight after rotating at 100 rpm for 30 minutes. The value of 100 rpm corresponded toapparent using the modified RVT at the standard setting
For barite sag evaluation, the test normally is conducted at 60-degree inclination with varying pump rates (from 25 to 185 fpm annular velocity) and pipe rotations (from 0 to 225 rpm). Changes of mud weight due to sagging/settling of barite or other weighting agent in the test tube are determined by the densitometer under circulating conditions.
Dynamic barite sag in the Drilling Research Projects (TUDRP) for their financial and technical field should be viewed as the combined effects of annular velocity, pipe support throughout this study. rotation, eccentricity, inclination angle and rheological properties of the drilling fluids.
The results also indicate that changing the inclination angle in the range from 60 to 45 degrees from vertical has the least impact on the prevention of barite sag.
These results provide new insight into the mechanisms of barite sag and how best to manage problems in the field. Data from the tests clearly demonstrate that the parameters affecting sag are interrelated and seldom act in isolation. For all muds tested, the highest sag occurred at low annular velocities over angles from 60 to 75°.
Barite sag is the undesirable fluctuations in mud weight that occur due to downhole settling of the weighting agent. The problem has been exacerbated by the increased frequency of high-angle wells with the associated increase in particle settling rate which occurs in inclined fluid columns (Boycott effect 1 ).
candidate for drilling high-angle and other critical wells where a low-viscosity profile will deliver reduced ECD, as well as providing the sag performance required in drilling these types of wells. The difference in particle-size distribution (PSD) between the ground barite resulting from this research project and normal API-ground barite is
Barite sag, usually manifested in deviated wells, can cause severe drilling problems. Drilling problems such as excessive torque, drag and lost circulation, due to increased equivalent circulating density (ECD), can be experienced during a sag episode. Typically, mitigating barite sag is a reactionary process. When barite sag is suspected, clay ...
The Grace Instrument M8500 High Pressure, High Temperature Dynamic Sagging Tester is designed for evaluating barite sagging and other weight material sag under simulated drilling conditions. It is also engineered for safe testing while providing ultra high pressure and high temperature sag test conditions.
Dec 19, 2012· While the causes of barite sag are not fully understood it is more prevalent in certain drilling conditions, such as high angle or deviated wells, temperature changes and static well conditions ...
(1) The onset of dynamic barite sag occurs at shear rates less than 4 s- 1 in deviated well bores with invert-emulsion mud. (2) Dynamic barite sag generally increases as the hole angle increases from 45° to 60°. (3) Ultra-low shear rate viscosity appears to have a greater influence on dynamic barite sag …
Excessive torque/drag, upright equivalent circulation densities, hindering drillpipe sliding which results in limiting the lateral reach of the well, lost circulation, barite sag, inefficient hole cleaning and frequent sticking are some of the engineering problems encountered while drilling horizontally.
Mar 18, 2016· Barite sag is a complex phenomenon and it is probably impossible to eliminate this process but it can be managed by a combination of good operational procedures and drilling fluid design. In deviated well, barite settlement can lead to down hole losses, mud weight fluctuations, stuck pipe and bore hole instability.
Under certain drilling conditions, the weighting material particles such as barite can settle out of the drilling fluid. This phenomenon, known as barite sag, can lead to a number of drilling problems including lost circulation, well control difficulties, poor cement job, and stuck pipe. This study investigates barite sag, both experimentally and numerically, in the annulus under flow conditions.
velocity, drill-pipe rotation, eccentricity, and inclination angle on dynamic barite sag; • Develop mathematical models for predicting dynamic barite sag in yield power law fluid (YPL) in an inclined annulus. ABSTRACT . This report presents the combined effects of eccentricity and pipe rotation on dynamic barite sag.
Mathematical modeling and experimental study of barite sag in annular flow to investigate effects of annular velocity, eccentricity, pipe rotation and inclination angle on barite sag. SCOPE OF WORK: Modeling: Velocity profile of a single phase fluid for a laminar flow in annulus with stationary inner pipe was obtained numerically. The ...
also influence barite sag in oil-based drilling fluids. The type and concentration of the emulsifier and wetting agent affect emulsion stability and the wettability of the solids, including organoclays, and may have an effect on sag4,8. To summarise, barite sag in OBM is related both to the mud properties and the
Barite sag is a significant variation in mud density caused by the settlement of barite or other weight material in high-angle wells. The wide fluctuations in mud weight can lead to severe operational problems, including well-control, induced wellbore instability, downhole mud losses, and stuck pipe.
Optimize ECD, reduce barite sag, and enhance ROP The RheGuard system delivers the consistently lower ECD and sag potential required for intricate intervals drilled in deepwater and other complex wells offshore. The system can eliminate the logistical complications and …
Considerations - Drilling Variables • Research and SPE papers have shown:- – Positive influence of drill pipe rotation – Barite sag increase with increased hole angle (from 45° to 60° ) – Threshold annular velocity of 100 feet/minute – Barite sag predominantly occurs under dynamic, low shear rate conditions • Logging • Slow Pump Rates • Tripping Pipe Barite Sag
the MicroBar additive that enables the fluid to maintain a low rheology and reduce the risk of barite sag. Compared with API-grade conventional barite that can be up to 75 um in size, the particle size of the MicroBar additive ranges from 5–8 um to approximately 25 um with a comparably higher surface area.
The high angle increased potential for barite sag. Elevated equivalent circulating density (ECD) was an added risk due to the narrow hole size; however, increased ECD could not be tolerated due to the narrow drilling window, as the fracture gradient was
A Comprehensive Approach to Barite Sag Analysis on Field Muds. ... Angle Sag Tester (DHA ST) tool was used t o measure barite . settling rates in tested drilling fluids. In br ief, the DHAST .
AADE-04-DF-HO-21 A UNIQUE TECHNICAL SOLUTION TO BARITE SAG IN DRILLING FLUIDS 3 mud. This data, together with well-specific information such as casing and drill-pipe configuration, and well and temperature profiles, were inputted into a proprietary
sag occurs at an annular velocity of 40 ft/min. (Dye et al. 1999). Hanson et al. (1990) showed that the sag tendency is significantly higher in wells with inclination angles of 30-60° from vertical. Bern et al. (1998) concluded that significant barite sag was measured at angles as high as 75° and the most critical range is 60 to 75°.
Jul 16, 2012· To design a low-ECD fluid that would improve barite sag resistance, Halliburton conducted sag analysis using the Dynamic High Angle Settling Test (DHAST) service, which provides a range of shear rate, temperature and pressure options to simulate downhole conditions.
Abstract Barite sag is a significant variation in mud density caused by the settlementof barite or other weight material in high-angle wells. The wide fluctuationsin mud weight can lead to severe operational problems, including well-control,induced wellbore instability, downhole mud losses, and stuck pipe.
This paper presents the quantitatively combined effects of the drilling parameters on dynamic barite sag in oil-based drilling fluids. The drilling parameters include annular velocity, pipe rotation, inclination angle, and eccentricity. Two levels for each parameter were considered to develop the test matrix in …
matically increase barite sag 2. Barite sag increases even faster as the hole angle increases to between 45° to 60°. This process was reported by Boycott in 1920, when he noticed that blood cells settled faster in inclined test tubes than in vertical tubes3. WEIGHTING AGENTS BaSO 4, which has a specific gravity (SG) of 4.2 and a particle
The occurrence of barite sag is a well recognized but poorly understood phenomenon in the drilling industry. Industry experts have offered a variety of measuring parameters, based upon empirical data, that only partially correlate with the occurrence of barite sag.
circulation, barite sag, inefficient hole cleaning and frequent sticking. These obstacles directly and indirectly contribute many other problems (Cameron, 2001). A small shift from the vertical due to the angle of deviation will lead to changing of the lifting power of the mud.