High temperature and high pressure rheological properties of high-density water-based drilling fluids for deep wells

Abstract In deep-water drilling, the drilling fluid is affected by the alternating temperature field derived from the low temperature of the seawater and the high temperature of the formation. The complicated wellbore temperature and pressure environments make the prediction of rheological properties of the drilling fluid difficult. In this study, the rheological properties of water-based drilling fluid in full temperature and pressure range of deep-water conditions were tested from 2 to 150 °C (35.6 to 302 °F) and 0.1 to 70 MPa (14.5 to 10000psi). The experiment was carried out by the OFI130-77 high temperature and high pressure rheometer. The experimental data were processed by multiple regression analysis method, and the mathematical model for predicting the apparent viscosity, plastic viscosity and yield point of water-based drilling fluid under high temperature and high pressure conditions was established. The experimental results show that when the temperature is lower than 65 °C (149 °F), the apparent viscosity and plastic viscosity of the water-based drilling fluid decrease significantly with increasing temperature. When the temperature is higher than 65 °C (149 °F), the apparent viscosity and plastic viscosity decrease slowly. Under low temperature conditions, the effect of pressure on the apparent viscosity and plastic viscosity of water-based drilling fluids is relatively significant. The calculated values of the prediction model have a good agreement with the experimental measurements. Compared with the traditional model, this prediction model has a significant improvement in the prediction accuracy in the low temperature section, which can provide a calculation basis for on-site application of deepwater drilling fluid.

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Clay minerals in drilling fluids: functions and challenges

Clay Minerals ◽

10.1180/clm.2020.10 ◽

2020 ◽

Vol 55 (1) ◽

pp. 1-11

Author(s):

Jun Rui Zhang ◽

Meng Dan Xu ◽

Georgios E. Christidis ◽

Chun Hui Zhou

Keyword(s):

High Pressure ◽

High Temperature ◽

Surface Chemistry ◽

Rheological Properties ◽

Clay Minerals ◽

Specific Structure ◽

Drilling Fluids ◽

Future Directions ◽

Water Based ◽

Slurry Walls

AbstractThe addition of clay minerals in drilling fluids modifies the dispersion's viscosity. In this article, scientific advances related to the use of clays and clay minerals (bentonite, palygorskite, sepiolite and mixtures of clay minerals) in drilling fluids are summarized and discussed based on their specific structure, rheological properties, applications, prevailing challenges and future directions. The rheological properties of drilling fluids are affected by the temperature, type of electrolytes, pH and concentration of clay minerals. Bentonites are smectite-rich clays often used in drilling fluids, and their composition varies from deposit to deposit. Such variations significantly affect the behaviour of bentonite-based drilling fluids. Palygorskite is suitable for use in oil-based drilling fluids, but the gelation and gel structures of palygorskite-added drilling fluids have not received much attention. Sepiolite is often used in water-based drilling fluids as a rheological additive. Dispersions containing mixtures of clays including bentonite, kaolin, palygorskite and sepiolite are used in drilling fluids requiring specific features such as high-density drilling fluids or those used in impermeable slurry walls. In these cases, the surface chemistry–microstructure–property relationships of mixed-clay dispersions need to be understood fully. The prevailing challenges and future directions in drilling fluids research include safety, ‘green’ processes and high-temperature and high-pressure-resistant clay minerals.

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The application of MWCNT to enhance the rheological behavior of drilling fluids at high temperature

Malaysian Journal of Fundamental and Applied Sciences ◽

10.11113/mjfas.v12n3.423 ◽

2017 ◽

Vol 12 (3) ◽

Cited By ~ 3

Author(s):

Abdul Razak Ismail ◽

W. R. W Sulaiman ◽

M. Z. Jaafar ◽

A. Aftab ◽

A. A. Razi ◽

...

Keyword(s):

High Temperature ◽

Rheological Properties ◽

Rheological Behavior ◽

Oil And Gas ◽

Drilling Fluid ◽

Gel Strength ◽

Drilling Fluids ◽

Deep Wells ◽

Multi Walled Carbon Nanotube ◽

Filtrate Loss

Drilling fluid is the key component to drill oil and gas wells. The rheological behavior of drilling fluid will be affected when drilling deep wells especially at high temperature and high pressure reservoir. This research was conducted to study the effect of the nanoparticles over the rheological properties of the drilling fluid when aging at high temperature condition. Several drilling fluids were prepared using synthetic based fluids (Sarapar and Saraline) to study the effect of multi-walled carbon nanotube (MWCNT) at different concentrations. The rheological properties of drilling fluid were analyzed after aging at 250 °F and 350 °F for 16 hours. The results revealed that the addition of MWCNT improved the 10-sec gel strength by 33% and filtrate loss volume was reduced to 10% after aging at 250°F in Saraline drilling fluid. Moreover, the plastic viscosity of Saraline and Sarapar drilling fluid after addition of MWCNT was enhanced by 6% and 27% at 350 °F. Filtrate loss volume of Sarapar drilling fluid was reduced by 19 % after aging at 250 °F for 16 hours. The overall results showed that the addition of MWCNT into the drilling fluid have slightly improved the rheological properties of drilling fluids under high temperature conditions.

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Study on the Rheological Properties of Ultra-High Temperature CGA Drilling Fluids

10.3233/atde210281 ◽

2021 ◽

Author(s):

Wenxi Zhu ◽

Xiuhua Zheng

Keyword(s):

High Temperature ◽

Rheological Properties ◽

High Temperatures ◽

Drilling Fluid ◽

Drilling Fluids ◽

Underbalanced Drilling ◽

Deep Wells ◽

Colloidal Gas Aphron ◽

Oil Gas ◽

Ultra High Temperature

Colloidal gas aphron (CGA) drilling fluids are a kind of environmentally-friendly underbalanced drilling technique, which has attracted more attention in depleted reservoirs and other low-pressure areas. With the shortage of global oil/gas resources, drilling has gradually shifted to high-temperature and deep wells. Hence, a study on the ultra-high temperature rheology properties of CGA fluids is lacking and urgently needed. In this study, a novel CGA drilling fluid system was prepared by modified starch and amino acid surfactant, and rheological properties after 120-300°C aged was investigate. Results show that: (1) Herschel-Bulkley model is the preferred model to predict CGA drilling fluid at ultra-high temperatures; (2) It was proved that CGA drilling fluid is a high-quality drilling fluid with extremely high value of LSRV and shear thinning property within 280°C. Compared to the traditional XG-based CGA drilling fluid, the improvement of LSRV at ultra-high temperatures is a significant advantage of EST-based CGA drilling fluid which is conducive to carrying cuttings and sealing formation pores.

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