scholarly journals A Combined Barite–Ilmenite Weighting Material to Prevent Barite Sag in Water-Based Drilling Fluid

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1945 ◽  
Author(s):  
Salem Basfar ◽  
Abdelmjeed Mohamed ◽  
Salaheldin Elkatatny ◽  
Abdulaziz Al-Majed
Keyword(s):  
Rheological Properties ◽  
Base Fluid ◽  
Drilling Fluid ◽  
Fluid Density ◽  
Fluid Filtration ◽  
Dynamic Conditions ◽  
Filtration Performance ◽  
Water Based ◽  
Static Conditions ◽  
The Impact

Barite sag is a serious problem encountered while drilling high-pressure/high-temperature (HPHT) wells. It occurs when barite particles separate from the base fluid leading to variations in drilling fluid density that may cause a serious well control issue. However, it occurs in vertical and inclined wells under both static and dynamic conditions. This study introduces a combined barite–ilmenite weighting material to prevent the barite sag problem in water-based drilling fluid. Different drilling fluid samples were prepared by adding different percentages of ilmenite (25, 50, and 75 wt.% from the total weight of the weighting agent) to the base drilling fluid (barite-weighted). Sag tendency of the drilling fluid samples was evaluated under static and dynamic conditions to determine the optimum concentration of ilmenite which was required to prevent the sag issue. A static sag test was conducted under both vertical and inclined conditions. The effect of adding ilmenite to the drilling fluid was evaluated by measuring fluid density and pH at room temperature, and rheological properties at 120 °F and 250 °F. Moreover, a filtration test was performed at 250 °F to study the impact of adding ilmenite on the drilling fluid filtration performance and sealing properties of the formed filter cake. The results of this study showed that adding ilmenite to barite-weighted drilling fluid increased fluid density and slightly reduced the pH within the acceptable pH range (9–11). Ilmenite maintained the rheology of the drilling fluid with a minimal drop in rheological properties due to the HPHT conditions, while a significant drop was observed for the base fluid (without ilmenite). Adding ilmenite to the base drilling fluid significantly reduced sag factor and 50 wt.% ilmenite was adequate to prevent solids sag in both dynamic and static conditions with sag factors of 0.33 and 0.51, respectively. Moreover, HPHT filtration results showed that adding ilmenite had no impact on filtration performance of the drilling fluid. The findings of this study show that the combined barite–ilmenite weighting material can be a good solution to prevent solids sag issues in water-based fluids; thus, drilling HPHT wells with such fluids would be safe and effective.

scholarly journals Prevention of Barite Sag in Water-Based Drilling Fluids by A Urea-Based Additive for Drilling Deep Formations

2020 ◽  
Vol 12 (7) ◽  
pp. 2719 ◽  
Author(s):  
Abdelmjeed Mohamed ◽  
Saad Al-Afnan ◽  
Salaheldin Elkatatny ◽  
Ibnelwaleed Hussein
Keyword(s):  
Base Fluid ◽  
Drilling Fluid ◽  
Gel Strength ◽  
Optimum Concentration ◽  
Drilling Fluids ◽  
Filtration Performance ◽  
Water Based ◽  
The Stability ◽  
Static Conditions ◽  
The Impact

Barite sag is a challenging phenomenon encountered in deep drilling with barite-weighted fluids and associated with fluid stability. It can take place in vertical and directional wells, whether in dynamic or static conditions. In this study, an anti-sagging urea-based additive was evaluated to enhance fluid stability and prevent solids sag in water-based fluids to be used in drilling, completion, and workover operations. A barite-weighted drilling fluid, with a density of 15 ppg, was used with the main drilling fluid additives. The ratio of the urea-based additive was varied in the range 0.25–3.0 vol.% of the total base fluid. The impact of this anti-sagging agent on the sag tendency was evaluated at 250 °F using vertical and inclined sag tests. The optimum concentration of the anti-sagging agent was determined for both vertical and inclined wells. The effect of the urea-additive on the drilling fluid rheology was investigated at low and high temperatures (80 °F and 250 °F). Furthermore, the impact of the urea-additive on the filtration performance of the drilling fluid was studied at 250 °F. Adding the urea-additive to the drilling fluid improved the stability of the drilling fluid, as indicated by a reduction in the sag factor. The optimum concentration of this additive was found to be 0.5–1.0 vol.% of the base fluid. This concentration was enough to prevent barite sag in both vertical and inclined conditions at 250 °F, with a sag factor of around 0.5. For the optimum concentration, the yield point and gel strength (after 10 s) were improved by around 50% and 45%, respectively, while both the plastic viscosity and gel strength (after 10 min) were maintained at the desired levels. Moreover, the anti-sagging agent has no impact on drilling fluid density, pH, or filtration performance.

scholarly journals Prevention of Barite Sag in Oil-Based Drilling Fluids Using a Mixture of Barite and Ilmenite as Weighting Material

2019 ◽  
Vol 11 (20) ◽  
pp. 5617 ◽  
Author(s):  
Abdelmjeed Mohamed ◽  
Salem Basfar ◽  
Salaheldin Elkatatny ◽  
Abdulaziz Al-Majed
Keyword(s):  
High Pressure ◽  
Viscoelastic Properties ◽  
Elevated Temperatures ◽  
Drilling Fluid ◽  
Solid Particles ◽  
Electrical Stability ◽  
Dynamic Conditions ◽  
Filtration Performance ◽  
Static Conditions ◽  
The Impact

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-weighted fluids are common for such purpose because of the good properties of barite, its low cost, and its availability. However, solids settlement is a major problem encountered with this type of fluids, especially at elevated downhole temperatures. This phenomenon is known as barite sag, and it is encountered in vertical and directional wells under static or dynamic conditions leading to serious well control issues. This study aims to evaluate the use of barite-ilmenite mixture as a weighting agent to prevent solids sag in oil-based muds at elevated temperatures. Sag test was conducted under static conditions (vertical and inclined) at 350 °F and under dynamic conditions at 120 °F to determine the optimum ilmenite concentration. Afterward, a complete evaluation of the drilling fluid was performed by monitoring density, electrical stability, rheological and viscoelastic properties, and filtration performance to study the impact of adding ilmenite on drilling fluid performance. The results of this study showed that adding ilmenite reduces sag tendency, and only 40 wt.% ilmenite (from the total weighting material) was adequate to eliminate barite sag under both static and dynamic conditions with a sag factor of around 0.51. Adding ilmenite enhanced the rheological and viscoelastic properties and the suspension of solid particles in the drilling fluid, which confirmed sag test results. Adding ilmenite slightly increased the density of the drilling fluid, with a slight decrease in the electrical stability within the acceptable range of field applications. Moreover, a minor improvement in the filtration performance of the drilling fluid and filter cake sealing properties was observed with the combined weighting agent. The findings of this study provide a practical solution to the barite sag issue in oil-based fluids using a combination of barite and ilmenite powder as a weighting agent to drill HPHT oil and gas wells safely and efficiently with such type of fluids.

scholarly journals Comparative Analysis of the Effect of Barite and Hematite on the Rheology of Water-Based Drilling Mud

2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Osei H
Keyword(s):  
Rheological Properties ◽  
Drilling Fluid ◽  
Attrition Rate ◽  
Drilling Mud ◽  
Cleaning Efficiency ◽  
Drilling Operation ◽  
Water Based ◽  
Petroleum Resources ◽  
Drilling Muds ◽  
The Impact

High demand for oil and gas has led to exploration of more petroleum resources even at remote areas. The petroleum resources are found in deeper subsurface formations and drilling into such formations requires a well-designed drilling mud with suitable rheological properties in order to avoid or reduce associated drilling problems. This is because rheological properties of drilling muds have considerable effect on the drilling operation and cleaning of the wellbore. Mud engineers therefore use mud additives to influence the properties and functions of the drilling fluid to obtain the desired drilling mud properties especially rheological properties. This study investigated and compared the impact of barite and hematite as weighting agents for water-based drilling muds and their influence on the rheology. Water-based muds of different concentrations of weighting agents (5%, 10%, 15% and 20% of the total weight of the drilling mud) were prepared and their rheological properties determined at an ambient temperature of 24ᵒC to check their impact on drilling operation. The results found hematite to produce higher mud density, plastic viscosity, gel strength and yield point when compared to barite at the same weighting concentrations. The higher performance of the hematite-based muds might be attributed to it having higher specific gravity, better particle distribution and lower particle attrition rate and more importantly being free from contaminants. The water-based muds with hematite will therefore be more promising drilling muds with higher drilling and hole cleaning efficiency than those having barite.

Filter Cake Properties of Water-Based Drilling Fluids Under Static and Dynamic Conditions Using Computed Tomography Scan

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Salaheldin Elkatatny ◽  
Mohamed Mahmoud ◽  
Hisham A. Nasr-El-Din
Keyword(s):  
Computed Tomography ◽  
Filter Cake ◽  
Drilling Fluid ◽  
Filter Press ◽  
Filter Medium ◽  
Drilling Fluids ◽  
Dynamic Conditions ◽  
Water Based ◽  
Porosity And Permeability ◽  
Static Conditions

Previous studies considered the water-based drilling fluid filter cake as homogenous, containing one layer with an average porosity and permeability. The filter cake was recently proved to be heterogeneous, containing two layers with different properties (thickness, porosity and permeability). Heterogeneity of the filter cake plays a key role in the design of chemical treatments needed to remove the filter cake. The objectives of this study are to describe filter cake buildup under static and dynamic conditions, determine change in the filter medium properties, and obtain the local filtration properties for each layer in the filter cake. A high pressure high temperature (HPHT) filter press was used to perform the filtration process at 225 °F and 300 psi. A CT (computed tomography) scanner was used to measure the thickness and porosity of the filter cake. The results obtained from the CT scan showed that under static conditions, the formation of filter cake changed from compression to buildup; while under dynamic conditions, the filter cake was formed under continuous buildup. The CT results explained the changes in the thickness and porosity of each layer of the filter cake with time. The CT scans showed the change in the properties of the ceramic disk, such as porosity and permeability, which affect the calculation of the filter cake permeability. The change of the properties of the filter medium was ignored in previous studies.

Effect of Ferric Oxide and Magnesium Oxide Nanoparticles on Iraqi Bentonite Performance in Water Based Drilling Fluid

2020 ◽  
Vol 27 (2) ◽  
pp. 14-23
Author(s):  
Ghofran F. Al-Ghanimi ◽  
Nada S. Al-Zubaidi
Keyword(s):  
Rheological Properties ◽  
Ferric Oxide ◽  
Drilling Fluid ◽  
Oil And Gas Industry ◽  
Nano Particles ◽  
Western Desert ◽  
Oxide Nanoparticles ◽  
Drilling Fluids ◽  
Water Based ◽  
The Impact

In oil and gas industry, the nanotechnology has been applied in different fields. Reservoir, exploration, drilling, completion, production, processing, and refinery are nanotechnology applications fields. Nanoparticles materials are one of the areas that are utilized in preparing drilling fluids. These nanomaterials are used to formulate high performance drilling fluids. In other words, these nano particles materials can be used to design smart drilling fluids. The properties of these drilling fluids can be met the well conditions requirements. The aim of this study is to enhance the performance of Iraqi bentonite in drilling fluids using nanomaterials. Iraqi calcium montmorillonite clay (Ca- bentonite) from Wadi Bashera in Iraqi Western Desert was obtained and studied in order to use it as an alternative active solid to the imported commercial bentonite. Water based drilling fluids were prepared with 3, 6, and 12 wt. % of Iraqi bentonite. Mgnesium oxide nanoparticles (MgO NPs) and ferric oxide nanoparticles (Fe2O3 NPs) with different concentrations were used. The experimental work showed that, MgO NPs resulted in a significant increase in the rheological properties of drilling fluids prepared with 3 and 6 wt. % of Iraqi bentonite. In contrast,  moderate effect on the rheological properties of drilling fluid prepared with 12 wt. % of Iraqi bentonite were obtained with low concentrations of Fe2O3 NPs. Basically drilling fluids prepared with Iraqi bentonite had extreme filtrate volume compared with API specifications and poor controlling to filtration properties were obtained with MgO NPs and Fe2O3 NPs additions. The impact of these two nanomaterials was revealed on the stability of drilling fluids prepared with Iraqi bentonite, where an enhancemment from 65 % to 100% was observed.

The Impact of Durian Rind in Water-based Mud in Combating Lost Circulation

2015 ◽  
Vol 74 (1) ◽  
Author(s):  
Issham Ismail ◽  
Anum Bisyarah Mohd Nor ◽  
Mohd. Fauzi Hamid ◽  
Abdul Razak Ismail
Keyword(s):  
Rheological Properties ◽  
Hot Rolling ◽  
Fine Particles ◽  
Drilling Fluid ◽  
Performance Comparison ◽  
Optimum Concentration ◽  
Lost Circulation ◽  
Water Based ◽  
The Impact ◽  
Durian Rind

A laboratory investigation has been done on durian rind, a fibrous material, as an alternative lost circulation material in water-based mud. The experimental works covered the rheological properties and lost circulation tests which were conducted before and after the hot-rolling tests as per API RP 13B. Those tests involved the use of standard mud testing equipment and a lost circulation test cell. The optimum concentration of the durian rind―which had been cleaned, cut into small pieces, dried in an oven at 60°C for 24 hours, and ground into small fine particles―was determined before a performance comparison study was done on both Hydro-plug (i.e., a commercial lost circulation material) and durian rind of different sizes, namely fine (0.5 mm), medium (1.0 mm), and coarse (2.0 mm). The experimental results showed that the durian rind worked well in combating the lost circulation. At its optimum concentration of 20 lb/bbl, the coarse durian rind was found to have performed excellently in combating lost circulation in 1 mm and 2 mm fractures. The standard rheological test showed that the rheological properties of drilling fluid were not too affected at standard temperature of 75°F but they changed significantly after the hot-rolling tests. The change in rheological properties was due to the flocculation of bentonite and chemical reaction of the pectin in durian rind.

Annular Frictional Pressure Losses During Drilling—Predicting the Effect of Drillstring Rotation

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Arild Saasen
Keyword(s):  
Rheological Properties ◽  
Pressure Loss ◽  
Drilling Fluid ◽  
Axial Flow ◽  
Drilling Fluids ◽  
Unstable Flow ◽  
Pressure Losses ◽  
Shear Dependent Viscosity ◽  
Water Based ◽  
Dependent Viscosity

Controlling the annular frictional pressure losses is important in order to drill safely with overpressure without fracturing the formation. To predict these pressure losses, however, is not straightforward. First of all, the pressure losses depend on the annulus eccentricity. Moving the drillstring to the wall generates a wider flow channel in part of the annulus which reduces the frictional pressure losses significantly. The drillstring motion itself also affects the pressure loss significantly. The drillstring rotation, even for fairly small rotation rates, creates unstable flow and sometimes turbulence in the annulus even without axial flow. Transversal motion of the drillstring creates vortices that destabilize the flow. Consequently, the annular frictional pressure loss is increased even though the drilling fluid becomes thinner because of added shear rate. Naturally, the rheological properties of the drilling fluid play an important role. These rheological properties include more properties than the viscosity as measured by API procedures. It is impossible to use the same frictional pressure loss model for water based and oil based drilling fluids even if their viscosity profile is equal because of the different ways these fluids build viscosity. Water based drilling fluids are normally constructed as a polymer solution while the oil based are combinations of emulsions and dispersions. Furthermore, within both water based and oil based drilling fluids there are functional differences. These differences may be sufficiently large to require different models for two water based drilling fluids built with different types of polymers. In addition to these phenomena washouts and tool joints will create localised pressure losses. These localised pressure losses will again be coupled with the rheological properties of the drilling fluids. In this paper, all the above mentioned phenomena and their consequences for annular pressure losses will be discussed in detail. North Sea field data is used as an example. It is not straightforward to build general annular pressure loss models. This argument is based on flow stability analysis and the consequences of using drilling fluids with different rheological properties. These different rheological properties include shear dependent viscosity, elongational viscosity and other viscoelastic properties.

Development of New Models to Determine the Rheological Parameters of Water-based Drilling Fluid Using Artificial Intelligence

2021 ◽  
Author(s):  
Farqad Hadi ◽  
Ali Noori ◽  
Hussein Hussein ◽  
Ameer Khudhair
Keyword(s):  
Rheological Properties ◽  
High Performance ◽  
Drilling Fluid ◽  
Gel Strength ◽  
Solid Content ◽  
Rheological Parameters ◽  
Water Based ◽  
Fluid Properties ◽  
Drilling Operations ◽  
Marsh Funnel

Abstract It is well known that drilling fluid is a key parameter for optimizing drilling operations, cleaning the hole, and managing the rig hydraulics and margins of surge and swab pressures. Although the experimental works present valid and reliable results, they are expensive and time consuming. On the other hand, continuous and regular determination of the rheological mud properties can perform its essential functions during well construction. More uncertainties in planning the drilling fluid properties meant that more challenges may be exposed during drilling operations. This study presents two predictive techniques, multiple regression analysis (MRA) and artificial neural networks (ANNs), to determine the rheological properties of water-based drilling fluid based on other simple measurable properties. While mud density (MW), marsh funnel (MF), and solid% are key input parameters in this study, the output functions or models are plastic viscosity (PV), yield point (YP), apparent viscosity (AV), and gel strength. The prediction methods were demonstrated by means of a field case in eastern Iraq, using datasets from daily drilling reports of two wells in addition to the laboratory measurements. To test the performance ability of the developed models, two error-based metrics (determination coefficient R2 and root mean square error RMSE) have been used in this study. The current results of this study support the evidence that MW, MF, and solid% are consistent indexes for the prediction of rheological properties. Both mud density and solid content have a relative-significant effect on increasing PV, YP, AV, and gel strength. However, a scattering around each fit curve is observed which proved that one rheological property alone is not sufficient to estimate other properties. The results also reveal that both MRA and ANN are conservative in estimating the fluid rheological properties, but ANN is more precise than MRA. Eight empirical mathematical models with high performance capacity have been developed in this study to determine the rheological fluid properties based on simple and quick equipment as mud balance and marsh funnel. This study presents cost-effective models to determine the rheological fluid properties for future well planning in Iraqi oil fields.

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