The yield stress of liquid-solid suspensions was evaluated experimentally on a static inclined plane apparatus in terms of the stability criterion.This equation was tested for 1000 < p< 183 1 kg/m3, 5.5 < H 5 38mm, 3.0 5 uy, 5 118 Pa. The results are compared with those obtained for the suspensions by vane torsion and by extrapolation of the flow-curve. Reasonable agreement was observed for 16 fluids with deviations in the range 0.2-48% (mean 15%). By comparison, the deviations between vane torsion and extrapolation of the flow-curve were comparable and in the range 2.2-90% (mean 19%).It was found necessary to roughen the base of the plane in order to avoid erratic behaviour, presumably due to slip. It was also found that the use of a shallow depth of test suspension gave more accurate results owing to less creeping and better applicability of the proposed criterion.The inclined plane technique holds promise for yield stress determination especially for application to processes in which concentrated suspensions flow down inclined surfaces. The technique is simple and cheap.
This reference is for an abstract only. A full paper was not submitted for this conference. Abstract The accurate determination of the velocity distribution in the subsurface is the single most important part in the long sequence of processing steps. Those accurate tomographic velocity models demand a state-of-the-art migration algorithms to honor the details that are needed in imaging the relevant complex structures. Controlled Beam Migration (CBM) is one of those techniques that exhibit an excellent impact on imaging Fractured and Faulted Granite basement. The velocity model that is used for depth imaging generally undergoes various iterations. It is the most difficult process, but yet also is the most important part of the velocity puzzle. Cell Based Tomography technique based on residual curvature analysis (RCA) was used for sediments velocity model building above the basement. In order to overcome the limitation of RCA tomography as it becomes less sensitive to velocity perturbation at deeper depth, Stack Sweep method has been performed to update the velocities inside the basement reservoir. This paper will concentrate mainly on the uplift of data imaging starting with Kirchhoff Pre Stack Time Migration passing through Kirchhoff Pre Stack Depth Migration and ending with Controlled Beam migration. CBM has a combined advantage of Kirchhoff migration (steep dip imaging) and Wave Equation Migration (multi-arrivals). It handles multi-arrivals, resulting in a cleaner image than Kirchhoff migration, and preserves the steep dips. Examples of the techniques are shown on data from Diamond Field, Offshore Vietnam with a discussion of specific issues that were encountered during processing.
The oil-bearing, fractured granite basement rocks are a very important and complicated hydrocarbon reservoir in offshore Vietnam. However, the poor S/N ratio and imaging of these steeply dipping fractures by conventional Kirchhoff migration are quite difficult to interpret for exploration. The recent development of Controlled Beam Migration (CBM) has generated a much clearer fracture image inside the basement, but the velocity inside the basement remains an issue. The imaging velocity field needs to be much slower than the well sonic velocity to produce a decent fracture image. With the help of the CBM stack sweeping technique, we have developed a new model building flow which takes into account the complex TTI/HTI anisotropy due to the micro-fracture system inside the basement. In this flow, the azimuthally dependant velocities for fractures are first picked through CBM stack sweeping; they are then compared with the well velocity trend to estimate the TTI/HTI anisotropy parameters. The azimuth angles are further updated by CBM stack sweeping with different azimuth angles. The resultant seismic velocities much better fit the sonic velocity logs. Also, the migrated section has much less migration swings from multiples, and the imaging of the major fault/fracture system is enhanced. Azimuth angles of the TTI (velocity) model and the improved fracture imaging provide the much needed information for the "From Seismic interpretation to Tectonic Reconstruction" methodology, which has been proven to be effective in exploration in the Cuu Long Basin for the last five years (Ngoc et al., 2010). The existence of TTI/HTI anisotropy inside the fractured basement is demonstrated through this case study. We have presented a new velocity modelling flow which can estimate the azimuth information for fracture systems and improve the imaging quality inside the basement.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.