Browsing by Subject "fluid flow"

Now showing 1 - 4 of 4

Access status: Open Access ,
Deformation bands – migration pathways or barriers for hydrocarbons in sedimentary rocks – mini review
(Wydawnictwa AGH, 2023) Solecki, Marek
A mini review of the topic of deformation bands is presented in the paper. The concept of deformation bands is defined and their impact on the flow of fluids in porous sedimentary rocks is determined. Deformation bands are mm-thick low-displacement deformation zones which have intensified cohesion and lower permeability compared with ordinary fractures. This term was introduced in 1968 in material science, ten years later it appeared in the geological context. This microstructures can occur as barriers or migration pathways for hydrocarbons. Their role depends mainly on microstructural features, and they are also considered in reservoir modeling. The occurrence of deformation bands in Poland is also outlined and discussed - they have been described in Western Outer Carpathians (Magura and Silesia nappes).
Access status: Open Access ,
Friction pressure loss determination of yield power law fluid in eccentric annular laminar flow
(2006) Ahmed, Ramdan; Miska, Stefan; Miska, Włodzimierz
Accurate predictions of friction pressure losses are very important in drilling and well completions operations. In some applications, for example, drilling in areas where the margin between pore pressure and fracture pressure gradients is small, inaccurate predictions of bore hole pressure may lead to serious complications and even a loss of the well. This paper is focused on a flow of yield power law type (pseudo-plastic with the yield stress) fluid in the annular space with the possibility that the inner pipe maybe eccentric. A new mathematical model that is based on a concept of generalized average wall shear rate - wall shear stress relationship is presented. A carefully designed laboratory facility that permits accurate differential pressure measurements as a function of flow rate in both pipe and annular flow has been developed. The desired rheology of the fluids was obtained by mixing two types of polymers (PAC and HEC) with water. Pipe flow measurements have been utilized to produce flow curves and subsequently the fluid rheological characterization (yield stress, consistency index and flow behavior index). The results of measured pressure losses are compared to those predicted by the proposed model. While the discrepancies are noticeable the difference is less than 15% and frequently is even less than 5%. We believe that the proposed model is simple useful for practical design applications.
Access status: Open Access ,
Identification of tectonic microstructures in flysch sandstones of the Outer Carpathians using X-ray nanotomography and nuclear magnetic resonance – first results
(Wydawnictwa AGH, 2015) Radzik, Natalia; Świerczewska, Anna; Krzyżak, Artur Tadeusz
Deformation bands and microfractures occurring in sandstones affect the petrophysical properties of the rock and determine fluid flow.
Access status: Open Access ,
Numerical simulation of drilling fluid flow in annular the space of the borehole
(2015) Kowalska-Kubsik, Iwona
This paper presents the numerical results of a numerical analys is of drilling fluid flow through annular space in the borehole. The analysis used the Herschel–Bulkley rheological fluid model. The obtained results of the analysis for three cases with variable geometry. Variable geometry is associated with a larger diameter drill in the joints of drill pipes, and consequently, with reduced flow cross-section. A comparison of pressure values at the end of the analyzed examples showed that in the example of a simple drill pipe with out joints, pressure values were 30% higher than in the case, which takes into account changes in the geometry of the joints.