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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, …
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 improper drilling conditions and practices.
Barite (BaSO 4) is a widespread mineral in deep-sea sediments, varying between 1% and 10% by weight on a carbonate-free basis.It is the predominant Ba phase in the ocean. BaSO 4 is known to compose a solid solution series with SrSO 4 as celestobarite in the skeletal portions of some marine organisms (i.e., the Xenophyophoria) and is often found in …
The new rheology modifier with additional low-gravity solids tolerance is more efficient and temperature-stable and provides enhanced barite suspension while minimizing barite sag tendency. This is a comparison of the rheology profiles of the original FRIDF and NFRS in the temperature range from 4.5°C to 65.5°C (40°F to 150°F)
This paper presents the analysis of drilling fluid field samples that were in current use by major operators. These samples were tested for barite sag behaviour using the Dynamic High Angle Sag ...
Barite sag is the settling of weight material, which results in significant drilling fluid density variations seen at the flow line. Barite sag is more severe in synthetic- based drilling …
Hanson et al.4 found that barite sag is most problematic under dynamic, not static, conditions. An important conclusion from this work was that barite sag generally observed in the field is primarily due to barite deposition occurring under dynamic conditions. Building upon this work Bern et al.5 induced barite sag by circulating at low
The change in the density of the 60/40 OBM and 80/20 OBM is 0.0888 sg, and 0.1887 sg, respectively. According to Maxey [66], the sagging potential of the drilling fluid is higher when the sag ...
This study presents an experimental analysis of dynamic barite sag phenomenon on a typical oil-based drilling fluid sample. All rheometry and dynamic barite sag tests were conducted at 50 o C ...
The dynamic high-angle sag tester (DHAST) (Fig. 6) determines the sag rate (mm/hr) using an inclined tube. The device could be used to mimic both static and …
design and optimization against barite sag. The dynamic high angle sag test was developed to aid in the analysis of dynamic and static barite "sag" in drilling fluids. The DHAST system provides a wide range of shear rate, temperature, and pressure options used to simulate downhole conditions. Since the beginning of 2003, the
that barite sag occurs under the following conditions: • In deviated wellbores at angles of 40-75º deviation • More prone to occur in invert emulsion drilling fluids
Sag "Shoe".6 This low-cost modification was developed to improve the consistency, sensitivity, and accuracy of the standard VST. The improved design also can characterize the sag bed to help determine the best course of action to correct a sag problem in the field. Like the original VST, the new version can also be used
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.
Effect of dynamic parameters on barite Sag. In the next stage, the effects of different parameters including flow rate and deviation angle were measured on the …
Barite sag occurs in drilling fluids exhibiting "low" low-end rheology. Barite sag occurrence is associated with low shear environments or with low shear environments followed with longer static environments. Barite sag usually occurs while circulating with average annular velocities (AV) of 100 ft/min (0.51m/s) or less. In the recent years ...
The occasional observation of barite sag in wells that used this mud system led to the investigation of low shear rate rheology measurements to minimize the occurrence of sag.
and reducing barite sag tendency. Abdou et al. [30] studied the effect of ilmenite and barite mixture Figure 1. Density variations resulted from solids sag phenomenon [23]. Several laboratory studies were performed to understand and prevent barite sag issue in water and oil-based drilling and completion fluids.
Perlite enhanced the drilling fluid's homogeneity and stability by reducing the dynamic and static sag factors, and 3.0 lb/bbl perlite was adequate to eliminate barite sag at a temperature up to ...
Abstract. Barite sag under static and dynamic conditions has been studied in the laboratory. Static sag has been related to viscoelastic properties of several fluids. These viscoelastic properties are related to gel formation which needs to be sufficient to keep barite in suspension. This static sag was not predictable by the use of standard VG …
Drilling high-pressure high-temperature (HPHT) wells requires a special fluid formulation that is capable of controlling the high pressure and is stable under the high downhole temperature. Barite …
Improved Prediction of Barite Sag Using a Fluid Dynamics Approach. A Unique Technical Solution to Barite Sag in Drilling Fluids. Role of Rheology in Barite Sag in SBM and OBM. Challenging Wells. Case History: Zero Whole Mud Losses Achieved During Casing and Cementing Operations on Challenging Deepwater Well Drilled with Clay-Free Synthetic ...
For the barite weighted base drilling fluid, the retrieved solids after HF stage (first stage) were immediately placed in the cell filled with in barite solvent (stage 2: chelating agent plus ...
Barite Application In Drilling Mud. Barite (barium sulfate, BaSO 4) contains 58.8 % barium and has a specific gravity of (4.2–4.5).The barite used in drilling fluid, which is normally impure, is of lower specific gravity as it contains other minerals such as quartz, chert, calcite, anhydrite, celestite, and various silicates.Also, it consists of other iron minerals, some of …
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°.
Weighting agents are mixed with the drilling mud to provide the high density required to control high-pressure high-temperature (HPHT) wells throughout the drilling operation. Solids sag occurs when the weighting agent separates from the liquid phase and settles down, causing variations in the drilling fluid density. This study evaluates …
Angle of i nclination also effects barite sag. In an inclined well, the distance that particle has to c over for settling is reduced and the particles settle more quickly on the lower sides of the ...
The increase in barite sag with shear rate is attributed to shear thinning. • Results of the parametric study indicated that barite sag decreases with OBM rheological parameters (τ y, K, and n). • For the mud used in the current study, barite sag is sensitive to the primary flow at low shear rates, approximately less than 30 s −1. Credit ...
The barite sag or weight material sag phenomenon is defined most appropriately by the API Work Group 3, formed under the aegis of API 13D subcommittee1, as follows: "Weight …
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 ...
Barite sag or weight material sag is a very well known "term" referring to unwanted variation in drilling fluid density after an extended period of static conditions. This topic is …
Angle Sag Tester (DHAST) tool was used to measure barite settling rates in tested drilling fluids. In brief, the DHAST ... AADE-13-FTCE-30 A Comprehensive approach to Barite Sag analysis on Field Muds 3 Table 4 – Field Sample 4 Properties Mud weight, ppg 17.5 OWR 80/20 Base Fluid Mineral Oil 2 ASG 4
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 …
a phase angle of greater than 90° and ... determined by the Eq. 1. Sag Factor = r bottom + r top r (1) ... be statistically likely to exhibit barite sag.