An Experimental Investigation of the The Effects of Ultra High Pressures and Temperatures on the Rheological Properties of Water-Based Drilling Fluids

Author(s):  
Mahmood Amani ◽  
Mohammed Jumaah Al-jubouri
Author(s):  
Wei-An Huang ◽  
Jing-Wen Wang ◽  
Ming Lei ◽  
Gong-Rang Li ◽  
Zhi-Feng Duan ◽  
...  

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Arild Saasen

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.


2020 ◽  
Vol 5 (10) ◽  
pp. 1269-1273
Author(s):  
Godwin Chukwuma Jacob Nmegbu ◽  
Bright Bariakpoa Kinate ◽  
Bari-Agara Bekee

The extent of damage to formation caused by water based drilling mud containing corn cob treated with sodium hydroxide to partially replace polyanionic cellulose (PAC) as a fluid loss control additive has been studied. Core samples were obtained from a well in Niger Delta for this study with a permeameter used to force the drilling mud into core samples at high pressures. Physio-chemical properties (moisture content, cellulose and lignin) of the samples were measured and the result after treatment showed reduction. The corn cob was combined with the PAC in the ratio of 25-75%, 50-50% and 75-25% in the mud. Analyzed drilling mud rheological properties such as plastic viscosity, apparent viscosity, yield point and gel strength all decreased as percentage of corn cob increased in the combination and steadily decreased as temperature increased to 200oF. Measured fluid loss and pH of the mud showed an increase in fluid loss and pH in mud sample with 100% corn cob. The extent of formation damage was determined by the differences in the initial and final permeability of the core samples. Experimental data were used to develop analytical models that can serve as effective tool to predict fluid loss, rheological properties of the drilling mud at temperature up to 200oF and percentage formation damage at 100 psi.


SPE Journal ◽  
2020 ◽  
Vol 25 (05) ◽  
pp. 2220-2233
Author(s):  
Weian Huang ◽  
Ming Lei ◽  
Jingwen Wang ◽  
Kaihe Lv ◽  
Lin Jiang ◽  
...  

Summary The rheology of drilling fluid is commonly regulated by chemical methods. In this work, a physical method of a high-frequency and high-voltage alternating current (AC) electric field to regulate the rheological properties of water-based drilling fluid is established. The effects of the electric field on the continuous phase and dispersed phase, as well as two kinds of water-based drilling fluids, were investigated, and the response relationship among rheological properties modeled by Bingham and Herschel-Bulkley (H-B) models and electric-field parameters was explored. Results showed that water conductivity increased when voltage reached 4 kV, whereas it was restored to the original state after 3 hours in the absence of an electric field, showing a memory effect. The effect was also observed on bentonite suspension, whose plastic viscosity increased with the aid of an electric field and decreased over time. Voltage showed the greatest effect on bentonite-suspension viscosity, followed by frequency and pulse-width ratio. Under the condition of voltage of 5 kV, frequency of 5 kHz, and pulse-width ratio of 80%, there was a maximum increase of 50% in viscosity. The addition of salts caused bentonite-suspension flocculation, and electric field reduced the consistency coefficient and relieved flocculation state. When polymers were incorporated in bentonite suspension, the electric field could decrease the adsorption amount between clay particles and polymeric additives such as amphoteric and acrylamide-based polymers. For two typical drilling fluids, the voltage of an introduced electric field was the main controlling factor to change the rheological properties; their plastic viscosity and consistency coefficient both started to increase when voltage reached 4 kV.


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