Analysis of operational window in Freeman technology uniaxial powder tester

2022 ◽  
pp. 117126
Author(s):  
Shoucheng Du ◽  
Timothy Bell ◽  
Massih Pasha
Keyword(s):  
Operational Window

Thermomechanical Evaluation of the Performance and Integrity of a HDPE Stub-End Bolted Flange Connection

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
I. Barsoum ◽  
Z. Barsoum ◽  
M. D. Islam
Keyword(s):  
Nonlinear Response ◽  
Structural Model ◽  
Temperature Dependent ◽  
Element Analysis ◽  
Fea Model ◽  
Operational Window ◽  
And Performance ◽  
Stub End ◽  
Parametric Finite Element Analysis ◽  
Bolted Flange

In this study, the integrity of a manhole structure made of a 78 in. high density polyethylene (HDPE) stub-end, steel ring, and blind flange, sealed with a compressed nonasbestos fiber (CNAF) gasket is investigated by means of a parametric finite element analysis (FEA). A coupled thermomechanical nonlinear FEA model is built, comprising of a heat transfer and a structural model, which allows modeling the complex thermal and mechanical loads and their interactions present during the operation of the manhole. The temperature-dependent elastic–plastic HDPE material constitutive behavior and the temperature-dependent nonlinear response of the CNAF gasket are accounted for in the model. Factors influencing the performance and integrity of the manhole such as stud-bolt pretorque level (Tb), internal pressure (Pi), and outer temperature (To) are considered. Based on the results, the integrity and performance of the structure are assessed in view of a leakage through the gasket criterion and a yielding of the HDPE stub-end criterion. The FEA results reveal that both Tb, Pi, and To significantly influence the performance (i.e., leakage) of the gasket and the integrity (i.e., yielding) of the HDPE stub-end. At 40 °C, it is possible to find a safe operational window for a range of Tb and Pi values, where no leakage through the gasket or yielding of the stub-end occurs. However, as the temperature is increased this safe operational window decreases considerably, and at 80 °C safe operation cannot be guaranteed where leakage, yielding, or both simultaneously, will lead to loss in performance and integrity of the manhole structure.

scholarly journals An Experimental Study to Reduce the Fracture Pressure of High Strength Rocks Using a Novel Thermochemical Fracturing Approach

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Zeeshan Tariq ◽  
Mohamed A. Mahmoud ◽  
A. Abdulraheem ◽  
Ayman Al-Nakhli ◽  
Mohammed BaTaweel
Keyword(s):  
Pressure Rise ◽  
High Strength ◽  
Hydrocarbon Reservoirs ◽  
Hydraulic Fractures ◽  
Breakdown Pressure ◽  
Fracture Pressure ◽  
Breakdown Time ◽  
Operational Window ◽  
Fracturing Experiments ◽  
Engineering Practices

Current oil prices and global financial situations underline the need for the best engineering practices to recover remaining oil from unconventional hydrocarbon reservoirs. These hydrocarbon reservoirs are mostly situated in deep and overpressured formations, with high rock strength and integrity. Breakdown pressure of the rock is a function of their tensile strength and in situ stresses acting on them. Fracturing stimulation techniques become challenging when treating these types of rocks, and many cases approached to the operational limits. This leaves a small operational window to initiate and place hydraulic fractures. In this study, a new methodology to reduce the breakdown pressure of the high stressed rock is presented. The new method enables the fracturing of high stressed rocks more economically and efficiently. Fracturing experiments were carried out on different blocks, and the breakdown pressure was measured by creating a simulated borehole at the center of the block. Thermochemical fluids were injected to create the microfractures. These microfractures improved the permeability and porosity and reduced the elastic strength of the subjected samples prior to the main hydraulic fracturing job. The posttreatment experimental analysis confirmed the presence of microfractures which were originated due to the pressure pulse generated from the thermochemical reaction. The results of this study showed that the newly formulated method of thermochemical fracturing reduced the breakdown pressure by 38% in slim borehole blocks and 60% in large borehole blocks. Results also showed that the breakdown time to initiate the fractures was reduced to 19% in slim borehole blocks and 17% in large borehole blocks. The reduction in breakdown pressure and breakdown time happened due to the creation of microfractures by the pressure rise phenomenon in a new thermochemical fracturing approach.

Design and Numerical Investigations on a Dual-Duct Variable Geometry RBCC Inlet

2020 ◽  
Vol 37 (2) ◽  
pp. 111-122 ◽  
Author(s):  
Xiaowei Liu ◽  
Lei Shil ◽  
Peijin Liu ◽  
Fei Qin ◽  
Guoqiang He
Keyword(s):  
Combined Cycle ◽  
High Mass ◽  
Variable Geometry ◽  
Status Transition ◽  
Flight Range ◽  
Operational Window ◽  
Mass Capture ◽  
Temperature Environment ◽  
Mach Numbers ◽  
High Mach

AbstractA widely applicable and variable geometry 2-D rocket based combined cycle (RBCC) inlet characterized by the dual-duct design is conceptually put forward. The inlet operates as dual-duct status in the low Mach range (0~4), and transits to single-flowpath status in the following high Mach range (4~7). It accomplishes operational status transition through an 8.0-degree ramp rotation and a 4.0-degree cowl rotation at Mach 4. Through numerical simulations on typical flight Mach numbers, the observed starting Mach number is 2.2, which provides a sufficient operational window for a smooth ejector-to-ramjet mode transition. The RBCC inlet achieves comprehensive high mass capture coefficients in the overall wide flight range, especially in the low speed regimes. Suitable Mach numbers satisfying various combustion requirements in different modes together with high total pressure recovery coefficients are also obtained since the physical throat areas, compression angles, and the corresponding contraction ratios can be adjusted by a large margin through very limited rotations. The variable geometry scheme is not only feasible for practical realizations, but is also simple to arrange the dynamic sealing issues in a low-temperature environment in the RBCC engine.

Using Managed Pressure Drilling Equipment to Troubleshoot Well Control Issues with Total Lost Circulation and Ballooning on A Semisubmersible Rig

2021 ◽  
Author(s):  
Harpreet Kaur Dalgit Singh ◽  
Ho Ching Shearn ◽  
Bao Ta Quoc ◽  
Dien Nguyen Van
Keyword(s):  
Control Device ◽  
Lost Circulation ◽  
Flow Monitoring ◽  
Operational Window ◽  
Managed Pressure Drilling ◽  
Coriolis Flowmeter ◽  
Open Hole ◽  
Bottom Hole Assembly ◽  
Bearing Assembly ◽  
Operating Window

Abstract When drilling from a deepwater semisubmersible rig, the operator encountered wells problems, including lost circulation, influxes, and ballooning, in the 14 3/4-in. hole section. Managed Pressure Drilling (MPD) equipment that helped to mitigate these issues specifically, when stripping in the hole with the bottom hole assembly through the Rotating Control Device (RCD) bearing assembly while managing surge and swab pressures, monitoring the well while displacing heavy mud into the open hole, conditioning the contaminated mud, removing gas from the well, and fingerprinting the flow back to verify ballooning against influxes, and finally stripping out of the hole. The operator experienced a total loss of circulation at the 16-in. liner shoe at 1,633m while drilling the 14 3/4-in. hole section. Several lost-circulation material (LCM) pills of different weights were pumped to cure the losses without success. Then the well was flow-checked, the gain was noted, and the well shut-in. Having the MPD chokes and the Coriolis flowmeter in place made it possible to adjust the surface back pressure (SBP) accordingly within a small operating window. As a result, the operator could achieve the key objectives of stripping the drillstring in the hole, stripping out of the hole, and rolling over to spot 1.88SG heavy mud on the bottom using the pump and pull method. After LCM was pumped and a hesitation squeeze performed, well operations were stabilized, and the casing was run to a 2,111m measured depth. Advanced flow monitoring enabled the MPD to determine the required SBP for balancing the well. MPD applied 60psi of SBP and noted a gain of 8.3bbl/hr from the flowmeter. Next, MPD applied 65psi SBP and the well was static. Then, MPD applied 70psi SBP, and the well took losses at a rate of 19bbl/hr. MPD allowed to successfully strip the BHA in the hole through the RCD bearing assembly to the shoe. Correct string displacement observed via the MPD Virtual Trip Tank, achieved by adjusting the SBP from 62psi to 125psi. The closed-loop circulating system enabled safely circulating and conditioning contaminated gas-cut mud in the hole back to homogeneous mud. MPD reduced SBP incrementally and fingerprinted flow back at every step to give assurance that well ballooning, and not influxes, caused the flow back. Dynamically adjusting SBP, coupled with advanced monitoring of the returns flow using the Coriolis flowmeter, enabled balancing the well despite the challenges of a mixed mud gradient in the annulus and a narrow operational window. The MPD riser consisted of an RCD below-tension-ring (BTR)-s, flow spool, and top and bottom crossovers. Rig modifications involved fabricating the fixed piping to allow integrating MPD equipment with the rig system.

CALIFORNIA OIL SPILL DISPERSANT PLAN-ACHIEVEMENT THROUGH COOPERATION

2005 ◽  
Vol 2005 (1) ◽  
pp. 433-437 ◽  
Author(s):  
Yvonne Najah Addassi ◽  
Ellen Faurot-Daniels
Keyword(s):  
Oil Spill ◽  
Coast Guard ◽  
Environmental Benefit ◽  
Decision Tool ◽  
Operational Window ◽  
Response Team ◽  
Oil Spill Response ◽  
Unified Command ◽  
National Significance ◽  
The U.S

ABSTRACT The use of dispersants in marine waters off California requires detailed foresight and planning. In an effort to expedite a decision to use dispersants and reduce first strike response time, the Region IX Regional Response Team tasked Californias Marine Area Committees to recommend dispersant approval zones. Each Area Committee conducted Net Environmental Benefit Analyses for their areas of responsibility, and from those analyses recommended dispersant zone designations to the U.S. Coast Guard and the Regional Response Team (RRT). All zone recommendations were approved by the RRT in July 2002, and development of the remaining elements of the dispersant plan began. Using primarily a model developed in New Zealand, the authors drafted a comprehensive dispersant use plan for the waters off California. The U.S. Coast Guard Captains of the Port in California reviewed the draft plan, and tested it during the April, 2004 Spill of National Significance (SONS) drill in southern California. The streamlined decision flowcharts, imbedded “Decision Boxes” and operational appendices with further instructions, forms and resource contact information, proved the California Dispersant Plan was a very intuitive and workable response decision tool. During the SONS drill, this greatly improved the ability of the Unified Command to make a decision regarding dispersant use, get the resources in place, and begin dispersant sorties within the operational “window” for dispersant use. It is expected that the same expedited and informed response process will serve California well during an actual oil spill response.

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