Topic
Annular velocity
About: Annular velocity is a research topic. Over the lifetime, 177 publications have been published within this topic receiving 3479 citations.
Papers published on a yearly basis
Papers
TL;DR: Both the systolic and early diastolic mitral annular velocities at the septum were lower than at other left ventricular sites, and the diastsolic tricuspid annular Velocities correlated well with transtricuspid Doppler diastolics parameters.
Abstract: Assessment of myocardial velocities by Doppler tissue imaging is gaining in importance. However, generally accepted reference values are still missing. In this study we examined 62 consecutive healthy subjects (mean age 46, range 22-82 years) by pulsed wave Doppler tissue imaging to characterize the systolic and diastolic velocity profiles of the left and right ventricles. The subjects were divided into 3 different age-groups: group I, younger than 40 years; group II, 40 to 59 years; and group III, 60 years and older. Recordings were made along the long axis in the apical 4- and 2-chamber views by using 4 sites (septal, anterior, lateral, and inferior) at the mitral annulus and 1 site at the tricuspid annulus. Systolic mitral annular velocity (10.3 +/- 1.4 cm/s) correlated strongly with global left ventricular function determined by M-mode echocardiographic mitral annular displacement (r = 0.70, P <.001). The systolic velocity was significantly lower in group III than in group I (9.6 vs 10.8 cm/s, P <.01). A relatively weak, but significant, correlation was found between systolic velocity and the age of the subjects (r = -0.43, P <.001). Mitral annular early diastolic velocity was also lower in group III compared with group I (11.3 vs 17.7 cm/s, P <.001), with a strong correlation with age (r = -0.81, P <.001) and other conventional Doppler diastolic parameters. Both the systolic and early diastolic mitral annular velocities at the septum were lower than at other left ventricular sites. Tricuspid annular systolic velocity (15.2 +/- 1.9 cm/s) was higher than mitral annular systolic velocity (P <.001). Unlike mitral annular velocity, systolic tricuspid annular velocity was not correlated with age. However, the diastolic tricuspid annular velocities correlated well with transtricuspid Doppler diastolic parameters. The method of recording the annular velocities was feasible in all subjects, simple and highly reproducible.
394 citations
TL;DR: In this paper, the authors present an analytical model for the flowing fluid temperature in the drillpipe/tubing and in the annulus as a function of well depth and circulation time.
Abstract: Estimation of fluid temperature in both flow conduits (drillpipe or tubing and the annulus) is required to ascertain the fluid density and viscosity and, in turn, to calculate the pressure drop or the maximum allowable pumping rate for a number of operations. These operations include drilling, workover, and well control. The fluid temperature estimation becomes critical for high-temperature or geothermal reservoirs where significant heat exchange occurs or when fluid properties are temperature sensitive, such as for a non-Newtonian fluid. In this work, the authors present an analytical model for the flowing fluid temperature in the drillpipe/tubing and in the annulus as a function of well depth and circulation time. The model is based on an energy balance between the formation and the fluid in the drillpipe.tubing and annulus. Steady-state heat transfer is assumed in the wellbore while transient heat transfer takes place in the formation. solutions are obtained for two possible scenarios: (1) the fluid flows down the annulus and up the drillpipe/tubing, and (2) the fluid flows down the tubing and up the annulus. The analytic model developed is cast in a set of simple algebraic equations for rapid implementation. The authors also show that the maximum temperature occursmore » not at the well bottom, but at some distance higher from the bottom for flow up the annulus.« less
229 citations
TL;DR: In this article, the results of an experimental study that was carried out to evaluate cuttings removal efficiency using three types of drilling fluid were evaluated using a 17-feet long opaque flow loop of 2-in. diameter as the test section.
Abstract: Deviation from vertical path makes drill cuttings to accumulate on the lower side of the wellbore that induces the formation of cuttings bed. Subsequently, relative problems occur while drilling. Excessive torque and drag, difficulties in running casing in hole and accomplishing good cementing jobs and mechanical pipe sticking are few of the classical examples of such problems. Therefore, a comprehensive understanding of influential parameters on hole cleaning seems to be essential. This paper indicates the results of an experimental study that was carried out to evaluate cuttings removal efficiency using three types of drilling fluid. The experimental works were conducted using a 17-feet long opaque flow loop of 2-in. diameter as the test section. For each test, the amount of cuttings transport performance (CTP) was determined from weight measurements. Viscosity was investigated together with other two influential parameters, namely fluid velocity and hole inclination under various flow conditions. It is shown that the increase in drilling fluid viscosity has improved CTP by approximately 8 % at all angles provided the flow regime remained turbulent while velocity was kept constant. However, further increase of viscosity as flow regime was turning into transient or laminar flow, has lessened CTP by a total average of 12 %. It was also revealed that an incremental escalation in hole inclination from 60° to 90° has a positive effect on CTP, i.e., it will be improved up to 40 %. Drilling fluid velocity was found to have significant impact on CTP as it could attain maximum percentage of 98 %.
118 citations
TL;DR: In this paper, the authors evaluated hole cleaning efficiency of an oil-based drilling fluid (OBM) and a water-based fluid (WBM) whose viscosity profiles are similar as per API specifications.
115 citations
TL;DR: In this article, a water-based and an oil-based drilling fluid have been investigated regarding their viscoelastic properties, using the Anton Paar rheometers MCR 102 and MCR 302.
105 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 3 |
| 2020 | 2 |
| 2019 | 4 |
| 2018 | 4 |
| 2017 | 7 |
| 2016 | 11 |