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Collaborating Authors
Drilling Fluids and Materials
Surge-and-Swab Pressure Predictions for Yield-Power-Law Drilling Fluids
Crespo, Freddy (University of Oklahoma) | Ahmed, Ramadan (University of Oklahoma) | Enfis, Majed (University of Oklahoma) | Saasen, Arild (Det norske oljeselskap and University of Stavanger) | Amani, Mahmood (Texas A&M University at Qatar)
Summary Surge and swab pressures have been known to cause formation fracture, lost circulation, and well-control problems. Accurate prediction of these pressures is crucially important in estimating the maximum tripping speeds to keep the wellbore pressure within specified limits of the pore and fracture pressures. It also plays a major role in running casings, particularly with narrow annular clearances. Existing surge/swab models are based on Bingham plastic (BP) and power-law (PL) fluid rheology models. However, in most cases, these models cannot adequately describe the flow behavior of drilling fluids. This paper presents a new steady-state model that can account for fluid and formation compressibility and pipe elasticity. For the closed-ended pipe, the model is cast into a simplified model to predict pressure surge in a more convenient way. The steady-state laminar-flow equation is solved for narrow slot geometry to approximate the flow in a concentric annulus with inner-pipe axial movement considering yield-PL (YPL) fluid. The YPL rheology model is usually preferred because it provides a better description of the flow behavior of most drilling fluids. The analytical solution yields accurate predictions, though not in convenient forms. Thus, a numerical scheme has been developed to obtain the solutions. After conducting an extensive parametric study, regression techniques were applied primarily to develop a simplified model (i.e., dimensionless correlation). The performance of the correlation has been tested by use of field and laboratory measurements. Comparisons of the model predictions with the measurements showed a satisfactory agreement. In most cases, the model makes better predictions in terms of closeness to the measurements because of the application of a more realistic rheology model. The correlation and model are useful for slimhole, deepwater, and extended-reach drilling applications.
- Europe (1.00)
- Asia (0.68)
- North America > United States > Texas (0.29)
- North America > United States > California (0.28)
- Research Report > Experimental Study (0.67)
- Research Report > New Finding (0.46)
- Well Drilling > Wellbore Design > Wellbore integrity (1.00)
- Well Drilling > Pressure Management > Well control (1.00)
- Well Drilling > Drilling Operations (1.00)
- (2 more...)
Temperature and pressure, however, increase with depth and therefore producing from such zones involves several challenges to petroleum engineers in terms of drilling, completion, and production. Among these challenges is the alteration of the rheological properties of drilling fluid (Ibeh, 2007). Understanding the rheological characteristics of the drilling fluids under elevated pressures and temperatures is essential for the drilling engineers. The general practice has been to measure a fluid's flow characteristics under ambient surface conditions and extrapolate these measurements to downhole conditions. This requires a reliable model of how the rheology of the fluid changes with the variations in temperature, pressure and shear history which it experiences during circulation inside the wellbore [4]. Despite considerable experimental studies over the years, there is relatively little systematic understanding of how the flow behavior changes with downhole conditions. The rheology of the fluid is influenced by many factors including temperature, pressure, shear history, composition and the electrochemical character of the components and of the continuous fluid phase [4]. 2 SPE 157219 This work focuses on investigating the rheological behavior of water-based drilling fluids with different properties at Ultra-HP/HT conditions using a state-of-the-art viscometer capable of measuring drilling fluids properties up to 600 F and 40,000 psig. Understanding the effect of these two factors, high temperature and pressure, is crucial for the purpose of designing an acceptable drilling fluid that can function properly in such environment.
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (1.00)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid management & disposal (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > HP/HT reservoirs (1.00)