The Critical Pressure Difference Prediction of Sand Production in Deepwater Sandstone Gas Reservoirs

2013 ◽  
Vol 31 (19) ◽  
pp. 1925-1932
Author(s):  
J. Deng ◽  
L. Wang ◽  
P. Li ◽  
W. Zhao
Keyword(s):  
Pressure Difference ◽  
Critical Pressure ◽  
Sand Production ◽  
Gas Reservoirs

scholarly journals A robust fuzzy logic-based model for predicting the critical total drawdown in sand production in oil and gas wells

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250466
Author(s):  
Fahd Saeed Alakbari ◽  
Mysara Eissa Mohyaldinn ◽  
Mohammed Abdalla Ayoub ◽  
Ali Samer Muhsan ◽  
Ibnelwaleed A. Hussein
Keyword(s):  
Fuzzy Logic ◽  
Correlation Coefficient ◽  
Oil And Gas ◽  
Maximum Error ◽  
Physical Parameters ◽  
Sand Production ◽  
Gas Reservoirs ◽  
The North ◽  
Sand Control ◽  
North Adriatic Sea

Sand management is essential for enhancing the production in oil and gas reservoirs. The critical total drawdown (CTD) is used as a reliable indicator of the onset of sand production; hence, its accurate prediction is very important. There are many published CTD prediction correlations in literature. However, the accuracy of most of these models is questionable. Therefore, further improvement in CTD prediction is needed for more effective and successful sand control. This article presents a robust and accurate fuzzy logic (FL) model for predicting the CTD. Literature on 23 wells of the North Adriatic Sea was used to develop the model. The used data were split into 70% training sets and 30% testing sets. Trend analysis was conducted to verify that the developed model follows the correct physical behavior trends of the input parameters. Some statistical analyses were performed to check the model’s reliability and accuracy as compared to the published correlations. The results demonstrated that the proposed FL model substantially outperforms the current published correlations and shows higher prediction accuracy. These results were verified using the highest correlation coefficient, the lowest average absolute percent relative error (AAPRE), the lowest maximum error (max. AAPRE), the lowest standard deviation (SD), and the lowest root mean square error (RMSE). Results showed that the lowest AAPRE is 8.6%, whereas the highest correlation coefficient is 0.9947. These values of AAPRE (<10%) indicate that the FL model could predicts the CTD more accurately than other published models (>20% AAPRE). Moreover, further analysis indicated the robustness of the FL model, because it follows the trends of all physical parameters affecting the CTD.

A single cell model for pretreatment of wood by microwave explosion

Holzforschung ◽  
2010 ◽  
Vol 64 (5) ◽  
Author(s):  
Xianjun Li ◽  
Yongdong Zhou ◽  
Yonglin Yan ◽  
Zhiyong Cai ◽  
Fu Feng
Keyword(s):  
Pressure Difference ◽  
Critical Pressure ◽  
Cell Model ◽  
Circumferential Stress ◽  
Longitudinal Direction ◽  
Critical Conditions ◽  
Maximum Pressure ◽  
Parenchyma Cells ◽  
Ray Parenchyma ◽  
Ray Parenchyma Cells

Abstract A theoretical model was developed to better understand the process of microwave explosion treatment of wood cells. The cell expansion and critical conditions concerning pressure and temperature of ray parenchyma cells in Eucalyptus urophylla were simulated during microwave pretreatment. The results indicate that longitudinal and circumferential stresses were generated in the cell walls owing to the internal steam pressure during extensive microwave treatment. The circumferential stress is twice as high as the longitudinal stress. The pressure difference reaches its maximum value of 0.84 MPa when the extension ratio is 1.20 for the longitudinal direction and 1.62 for the circumferential direction. The maximum pressure difference at the theoretical yielding point is the critical pressure difference that can eventually rupture the ray cell. The critical pressure difference decreases with increasing cell radius and decreasing shear modulus in the cell wall. This simulated result provides useful information to modify wood at the level of ray parenchyma cells.

Numerical Analysis of Smoke Confinement by Means of Air Curtains in High-Rise Buildings

2016 ◽  
Vol 858 ◽  
pp. 287-293 ◽  
Author(s):  
Xiao Tao Zhang ◽  
Chong Tan ◽  
Yu Shi Lu
Keyword(s):  
Pressure Difference ◽  
Critical Pressure ◽  
Discharge Coefficient ◽  
Wind Effect ◽  
Cfd Simulations ◽  
Air Curtain ◽  
High Rise ◽  
Discharge Velocity ◽  
Fire Effect ◽  
Computational Fluid Dynamics Cfd

As an effective approach to confine fire-induced smoke transportation, the application of air curtains is introduced in high-rise buildings during fire. A series of computational fluid dynamics (CFD) simulations were carried out for a full scale corridor in high-rise building, in which different factors such as air curtain discharge velocity (ACDV), human evacuation and pressure difference are considered. The results show that with the ACDV increasing, the smoke flowing resistance of air curtain is greater. The factor of evacuation cause significant impact on the efficiency of air curtain. Compared with the pressure difference caused by wind effect, the fire effect would lead to higher critical pressure difference and discharge coefficient.

Propagation of an Air Finger Into a Fluid Filled Bifurcation

2010 ◽  
Author(s):  
Benjamin L. Vaughan ◽  
James B. Grotberg
Keyword(s):  
Numerical Model ◽  
Viscous Fluid ◽  
Pressure Difference ◽  
Respiratory Diseases ◽  
Critical Pressure ◽  
Distress Syndrome ◽  
The Other ◽  
Liquid Plug ◽  
Pulmonary Airways ◽  
Single Branch

The occlusion of pulmonary airways can be caused by many respiratory diseases such as respiratory distress syndrome. It is believed that these occluded airways are reopened by the propagation of an air finger. The mechanics of airway reopening have been studied in-depth for an individual airway [1,2] without considering the frequent branching of pulmonary airways. The presence of a bifurcation leads to the question of whether the propagating air finger will clear both branches of the airway or will propagate through a single branch, leaving the other branch occluded. The propagation of a finite length liquid plug through a fixed bifurcation has been studied experimentally [3, 4]. We wish to develop a numerical model for the propagation of an air finger through bifurcating channel filled with a viscous fluid. In this model, the air finger is driven by a pressure difference between the parent channel and the two daughter branches. The presence of an additional pressure difference between the two branches can cause unsymmetrical splitting of the air finger and, above a critical pressure difference, prevent the clearance of both branches.

scholarly journals Simulation of the Gas Filling and Evacuation Processes in an Inertial Confinement Fusion (ICF) Hohlraum

Processes ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 269
Author(s):  
Liangyu Wu ◽  
Hua Zhou ◽  
Cheng Yu ◽  
Feng Yao
Keyword(s):  
Mass Flow ◽  
Pressure Difference ◽  
Inertial Confinement Fusion ◽  
Critical Pressure ◽  
Flow Simulation ◽  
Pressure Variation ◽  
Inertial Confinement ◽  
Confinement Fusion ◽  
Variation Rate ◽  
Hole Number

In indirect inertial confinement fusion (ICF), the prediction of gas pressures and mass flow rates in the hohlraum is critical for fielding the hohlraum film and the support tent. To this end, it is desirable to understand the gas filling and evacuation process through the microcapillary fill tube and the support tent. In this work, a unified flow simulation of the filling and evacuation processes through the microcapillary fill tube and the support tent in an ICF hohlraum was conducted to study the gas pressure and mass flow rate in the hohlraum. The effects of the support tent size and the microcapillary fill tube size on the critical pressure variation and pressure difference across the hole on the support tent are examined. The results indicate that an increase in the diameter of the hole and the hole number leads to a smaller pressure difference across the hole on the support tent. If the diameter of the hole on the support tent is larger than 0.06 mm, the critical pressure variation rate is nearly independent of the diameter and the hole number. Increases in the diameter and decreases in the length of the microcapillary fill tube induce a larger critical pressure variation rate and pressure difference across the hole, which is conductive to fielding the hohlraum film.

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