• Application of the quemada viscosity model for drilling fluids 

      Knutsen, Sandra; Cayeux, Eric; Saasen, Arild; Khalifeh, Mahmoud (Chapter, 2021)
      A number of different models are used to describe the shear rate dependent viscosity of drilling fluids. Most, such as the Herschel-Bulkley model, have a purely empirical basis. The Quemada model, while still empirical, ...
    • Criterion for sufficiently large dither amplitude to mitigate non-linear glitches 

      Faza, Ahmad Mohammad Ahmad; Leth, John; Eielsen, Arnfinn Aas (Chapter, 2023)
      A model describing glitch disturbances is introduced and analysed. The model is used to find the response of glitch disturbances when adding a periodic dither to the input and applying low-pass filtering to the output. ...
    • Cuttings transport with oil- and water-based drilling fluids 

      Ytrehus, Jan David; Lund, Bjørnar; Taghipour, Ali; Saasen, Arild (Chapter, 2021)
      Deviated well sections are common in modern well construction. In mature areas like the North Sea region, practically all producers or injector wells will have highly deviated sections. These wells must be drilled and ...
    • Effect of Organic Retarders on Fluid-State and Strength Development of Rock-Based Geopolymer 

      Kamali, Mohammadreza; Khalifeh, Mahmoud; Samarakoon, Mudiyansele Samindi Manjula K; Salehi, Saeed; Wu, Yuxing (Chapter, 2023)
      Granite waste is rich in aluminum and silicate has the potential of turning to geopolymer material after mixing with an alkali solution. One of the challenges in developing a geopolymer is to select a suitable retarder to ...
    • Hydraulic Behavior in Cased and Open Hole Sections in Highly Deviated Wellbores 

      Ytrehus, Jan David; Lund, Bjørnar; Taghipour, Ali; Kosberg, Birgitte Ruud; Carazza, Luca; Gyland, Knud Richard; Saasen, Arild (Chapter, 2019)
      In this paper we present results from flow loop experiments with an oil-based drilling fluid with micronized barite as weight materials. The use of micronized barite allows using lower viscosity drilling fluid, providing ...
    • Learning control applied to a digital-to-analogue converter 

      van Rijt, Noa; Faza, Ahmad Mohammad Ahmad; Oomen, Tom; Eielsen, Arnfinn Aas (Chapter, 2023)
      Digital-to-analogue converters (DACs) exhibit several non-ideal effects that deteriorate performance. Methods in feedback control can reduce such effects. Due to implementation limitations, the feedback signal in existing ...
    • Numerical Modelling and Sensitivity Analysis of Gas Kick Migration and Unloading of Riser 

      de Sousa Gomes, Dalila; Bjørkevoll, Knut Steinar; Fjelde, Kjell Kåre; Frøyen, Johnny (Chapter, 2019)
      In deepwater wells there is a risk of gas entering the riser. This can be caused by gas being trapped by the BOP after a well kill operation, or it can be that the BOP was not closed quickly enough upon kick detection. ...
    • Pressure Build-Up in Closed Wells During Kick Migration and Fluid Compressibility Effects 

      Agonafir, Mesfin Belayneh; Petersen, Johnny; Fjelde, Kjell Kåre (Chapter, 2022)
      If a kick is migrating in a closed well, this will lead to pressures building up in the well. It has earlier been shown that for Non-Newtonian fluids, suspension effects will make it impossible to deduce a unique gas ...
    • Use of a transient model for studying kick migration velocities and build-up pressures in a closed well 

      Hang Ngoc Tat, Thea; Gomes, Dalila; Fjelde, Kjell Kåre (Chapter, 2021)
      The objective of the paper is to show that using pressure build-up curves for estimating kick migration velocities can be unreliable. This will be demonstrated by using a transient flow model where different flow patterns ...