Activated Shale Creep and Potential Micro-Annulus Investigated in the Field

2021 ◽  
Author(s):  
Andreas Bauer ◽  
Matteo Loizzo ◽  
Laurent Delabroy ◽  
Tron Golder Kristiansen ◽  
Kristian Klepaker
Keyword(s):  
Core Sample ◽  
Inversion Algorithm ◽  
Log Data ◽  
Sealing Capacity ◽  
Large Pressure ◽  
Elastic Rebound ◽  
Zonal Isolation ◽  
Pressure Changes ◽  
Drilling Muds ◽  
The Impact

Abstract It has been demonstrated that creeping shales can form effective hydraulic well barriers. Shale barriers have been used for many years in P&A of wells in Norway. More recently, shale barriers for zonal isolation have also been used in new wells where shale creep was found to occur within days. In some cases, shale creep is activated by a reduction in annulus pressure, in other cases shale creep sets in without any active activation, possibly by time-dependent formation-pressure changes. However, the presence of thixotropic fluids (drilling muds) in the annulus may prevent full closure of the annulus as it requires large pressure differentials to squeeze the fluid out of a microannulus. Furthermore, elastic rebound of an actively activated shale barrier could result in a microannulus and hence a possible leakage pathway. Improved logging technology is needed for identifying shale barriers and the presence of micro-annuli in shale-barrier zones. We use cement bond log data and standard bond logging criteria to evaluate the quality of the shale well barriers (Williams et al., 2009). In addition, in order to detect microannuli on the outside of the casing, a new inversion algorithm for the bond logging data was developed and tested on field data. Later, we had the chance to apply the inversion algorithm to bond-log data obtained in the laboratory with a miniature bond-logging tool inside a cased hollow-cylinder shale-core sample place. It turned out that both the micro-annulus widths and shale velocities determined by the inversion technique were too high. By constraining the shale velocities to more realistic values, the updated microannulus widths were smaller and more consistent with the experimental results. Small microannuli may not cause any measurable leakage along the well, especially if filled with a thixotropic fluid. However, more studies are needed to quantify the impact of microannuli on the sealing capacity of shale barriers.

Evaluation of New Innovative Cement Blend for Enhanced CO2 and H2S Resistance

2021 ◽  
Author(s):  
Gunnar Lende ◽  
Jill Angelique Clausen ◽  
Astri Jager Kvassnes
Keyword(s):  
Cement Matrix ◽  
The Novel ◽  
Displacement Efficiency ◽  
Flow Paths ◽  
Chemical Attack ◽  
Zonal Isolation ◽  
Comprehensive Test ◽  
Short And Long Term ◽  
Pressure Changes ◽  
The Impact

Abstract Achieving zonal isolation is incumbent upon preventing undesirable flow of hydrocarbons, carbon dioxide, and hydrogen sulfide, as well as other fluids. The risks associated with zonal isolation being compromised come from different mechanisms, such as insufficient displacement efficiency, tubular corrosion, cement cracking, micro-annuli from hydration shrinkage or pressure changes as well as erosion. It is therefore important to understand how CO2, H2S and other factors interact with cement under downhole conditions. The cementing materials are important to the short- and long-term integrity of the well and helping to ensure that no unwanted flow paths are formed that can threaten the safety, health and environment, and also the impact on the profitable life of the well. Thus, pathways for CO2 and H2S as well as other fluids should be avoided and blocked if they occur. Described herein is the evaluation of a novel cement admixture developed for improving the resistance of the cement matrix to chemical attack from CO2 and H2S, and its incorporation in a tailored cement design. The development of this design focused on applications in wells in the Norwegian Waters where CO2 and H2S are present. A comprehensive test program using customized equipment provided the necessary information to evaluate the performance. Further discussed are methods developed to test and evaluate the performance of this new design as effectively as possible by using available test equipment in new ways and new combinations. Test results support the novel cement admixture combined with ordinary Portland cement (OPC) in terms of pumpability, curing time, permeability and mechanical properties is technically and financially viable given that necessary blend optimization is done. Hence, the cement blend can be used without changing the existing cement infrastructure, methods, vetting and procedures that exist for well cementing today. Finally, the outcome of the first field test on an offshore permanent abandonment plug as part of a mature field plug and abandonment campaign is briefly referenced.

Pressure Gradients Affecting the Labyrinth during Hypobaric Pressure

1997 ◽  
Vol 106 (6) ◽  
pp. 495-502 ◽  
Author(s):  
Konrád S. Konrádsson ◽  
Björn I. R. Carlborg ◽  
Joseph C. Farmer
Keyword(s):  
Cerebrospinal Fluid ◽  
Eustachian Tube ◽  
Ambient Pressure ◽  
Pressure Gradients ◽  
Cochlear Aqueduct ◽  
Fluid Compartment ◽  
Large Pressure ◽  
Fluid Compartments ◽  
Pressure Changes ◽  
Considerable Pressure

Hypobaric effects on the perilymph pressure were investigated in 18 cats. The perilymph, tympanic cavity, cerebrospinal fluid, and systemic and ambient pressure changes were continuously recorded relative to the atmospheric pressure. The pressure equilibration of the eustachian tube and the cochlear aqueduct was studied, as well as the effects of blocking these channels. During ascent, the physiologic opening of the eustachian tube reduced the pressure gradients across the tympanic membrane. The patent cochlear aqueduct equilibrated perilymph pressure to cerebrospinal fluid compartment levels with a considerable pressure gradient across the oval and round windows. With the aqueduct blocked, the pressure decrease within the labyrinth and tympanic cavities was limited, resulting in large pressure gradients toward the chamber and the cerebrospinal fluid compartments, respectively. We conclude that closed cavities with limited pressure release capacities are the cause of the pressure gradients. The strain exerted by these pressure gradients is potentially harmful to the ear.

scholarly journals Clinical Epidemiology of Systolic and Diastolic Orthostatic Hypotension in Patients on Peritoneal Dialysis

2021 ◽  
Vol 10 (14) ◽  
pp. 3075
Author(s):  
Claudia Torino ◽  
Rocco Tripepi ◽  
Maria Carmela Versace ◽  
Antonio Vilasi ◽  
Giovanni Tripepi ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Peritoneal Dialysis ◽  
Orthostatic Hypotension ◽  
Clinical Epidemiology ◽  
Hemodialysis Patients ◽  
Excess Death ◽  
Death Risk ◽  
Standardized Protocol ◽  
Pressure Changes ◽  
The Impact

Blood pressure changes upon standing reflect a hemodynamic response, which depends on the baroreflex system and euvolemia. Dysautonomia and fluctuations in blood volume are hallmarks in kidney failure requiring replacement therapy. Orthostatic hypotension has been associated with mortality in hemodialysis patients, but neither this relationship nor the impact of changes in blood pressure has been tested in patients on peritoneal dialysis. We investigated both these relationships in a cohort of 137 PD patients. The response to orthostasis was assessed according to a standardized protocol. Twenty-five patients (18%) had systolic orthostatic hypotension, and 17 patients (12%) had diastolic hypotension. The magnitude of systolic and diastolic BP changes was inversely related to the value of the corresponding supine BP component (r = −0.16, p = 0.056 (systolic) and r = −0.25, p = 0.003 (diastolic), respectively). Orthostatic changes in diastolic, but not in systolic, BP were linearly related to the death risk (HR (1 mmHg reduction): 1.04, 95% CI 1.01–1.07, p = 0.006), and this was also true for CV death (HR: 1.08, 95% CI 1.03–1.12, p = 0.001). The strength of this association was not affected by further data adjustment (p ≤ 0.05). These findings suggest that independent of the formal diagnosis of orthostatic hypotension, even minor orthostatic reductions in diastolic BP bear an excess death risk in this population.

scholarly journals Comparative Analysis of the Effect of Barite and Hematite on the Rheology of Water-Based Drilling Mud

2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Osei H
Keyword(s):  
Rheological Properties ◽  
Drilling Fluid ◽  
Attrition Rate ◽  
Drilling Mud ◽  
Cleaning Efficiency ◽  
Drilling Operation ◽  
Water Based ◽  
Petroleum Resources ◽  
Drilling Muds ◽  
The Impact

High demand for oil and gas has led to exploration of more petroleum resources even at remote areas. The petroleum resources are found in deeper subsurface formations and drilling into such formations requires a well-designed drilling mud with suitable rheological properties in order to avoid or reduce associated drilling problems. This is because rheological properties of drilling muds have considerable effect on the drilling operation and cleaning of the wellbore. Mud engineers therefore use mud additives to influence the properties and functions of the drilling fluid to obtain the desired drilling mud properties especially rheological properties. This study investigated and compared the impact of barite and hematite as weighting agents for water-based drilling muds and their influence on the rheology. Water-based muds of different concentrations of weighting agents (5%, 10%, 15% and 20% of the total weight of the drilling mud) were prepared and their rheological properties determined at an ambient temperature of 24ᵒC to check their impact on drilling operation. The results found hematite to produce higher mud density, plastic viscosity, gel strength and yield point when compared to barite at the same weighting concentrations. The higher performance of the hematite-based muds might be attributed to it having higher specific gravity, better particle distribution and lower particle attrition rate and more importantly being free from contaminants. The water-based muds with hematite will therefore be more promising drilling muds with higher drilling and hole cleaning efficiency than those having barite.

HYSTERESIS IN SILICA GEL SORPTION SYSTEMS

1934 ◽  
Vol 10 (6) ◽  
pp. 713-729 ◽  
Author(s):  
L. M. Pidgeon
Keyword(s):  
Hysteresis Loop ◽  
Silica Gel ◽  
Sulphur Dioxide ◽  
Water System ◽  
The Other ◽  
Vapor Pressures ◽  
Large Pressure ◽  
Pressure Changes ◽  
Permanent Gases ◽  
Sorption Systems

The hysteresis which normally appears in the isotherms of the silica gel-water system has been attributed by Patrick to the presence of permanent gases in the system. Only one case has been found in which a reversible isotherm has been recorded in the silica gel-water system. For alcohol and benzene only one case of hysteresis has been reported. These results seem to be independent of the presence or absence of air or other gases.The sorption of water, benzene and ethyl alcohol has been examined using the sorption balance. A hysteresis loop appears for water only. This hysteresis may not be eliminated by special methods of evacuation and must be considered as a real effect. The isotherms of alcohol and benzene, on the other hand, are completely reversible. It has been shown that the dimensions of the hysteresis occurring in the water system may be affected by the manner of addition of vapor to the apparatus. Only when the vapor pressures remain reasonably constant during sorption are the dimensions of the effect evident. If very large pressure changes take place the hysteresis may disappear.A comparison of the isotherms for water showing hysteresis, and those of the sulphur dioxide system (upon which the original suggestion as to the cause of hysteresis was based) show that there is not necessarily any relation between the two.

scholarly journals Impact of blood pressure changes in cerebral blood perfusion of patients with ischemic Moyamoya disease evaluated by SPECT

2020 ◽  
pp. 0271678X2096745
Author(s):  
Zhao Liming ◽  
Sun Weiliang ◽  
Jia Jia ◽  
Liang Hao ◽  
Liu Yang ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Moyamoya Disease ◽  
Emission Computed Tomography ◽  
Study Cohort ◽  
Pressure Changes ◽  
The Impact

Our aim was to determine the impact of targeted blood pressure modifications on cerebral blood flow in ischemic moyamoya disease patients assessed by single-photon emission computed tomography (SPECT). From March to September 2018, we prospectively collected data of 154 moyamoya disease patients and selected 40 patients with ischemic moyamoya disease. All patients underwent in-hospital blood pressure monitoring to determine the mean arterial pressure baseline values. The study cohort was subdivided into two subgroups: (1) Group A or relative high blood pressure (RHBP) with an induced mean arterial pressure 10–20% higher than baseline and (2) Group B or relative low blood pressure (RLBP) including patients with mean arterial pressure 10–20% lower than baseline. All patients underwent initial SPECT study on admission-day, and on the following day, every subgroup underwent a second SPECT study under their respective targeted blood pressure values. In general, RHBP patients showed an increment in perfusion of 10.13% (SD 2.94%), whereas RLBP patients showed a reduction of perfusion of 12.19% (SD 2.68%). Cerebral blood flow of moyamoya disease patients is susceptible to small blood pressure changes, and cerebral autoregulation might be affected due to short dynamic blood pressure modifications.

scholarly journals Modern Modeling of Water Hammer

2017 ◽  
Vol 24 (3) ◽  
pp. 68-77 ◽  
Author(s):  
Kamil Urbanowicz
Keyword(s):  
Side Effects ◽  
Adverse Effects ◽  
Water Hammer ◽  
Hydraulic Systems ◽  
Weighting Functions ◽  
Transient Flows ◽  
Hydraulic Equipment ◽  
Pressure Changes ◽  
The Impact ◽  
Reduced Pressures

Abstract Hydraulic equipment on board ships is common. It assists in the work of: steering gear, pitch propellers, watertight doors, cargo hatch covers, cargo and mooring winches, deck cranes, stern ramps etc. The damage caused by transient flows (which include among others water hammer) are often impossible to repair at sea. Hence, it is very important to estimate the correct pressure runs and associated side effects during their design. The presented study compares the results of research on the impact of a simplified way of modeling the hydraulic resistance and simplified effective weighting functions build of two and three-terms on the estimated results of the pressure changes. As it turns out, simple effective two-terms weighting functions are able to accurately model the analyzed transients. The implementation of the presented method will soon allow current automatic protection of hydraulic systems of the adverse effects associated with frequent elevated and reduced pressures.

Analysis of Hot Oil Pipeline Stress Influencing Factors

2014 ◽  
Vol 887-888 ◽  
pp. 899-902
Author(s):  
Xiao Nan Wu ◽  
Shi Juan Wu ◽  
Hong Fang Lu ◽  
Jie Wan ◽  
Jia Li Liu ◽  
...  
Keyword(s):  
Crude Oil ◽  
High Viscosity ◽  
Analysis Model ◽  
Long Distance ◽  
Oil Pipeline ◽  
Software Analysis ◽  
Key Points ◽  
Temperature And Pressure ◽  
Pressure Changes ◽  
The Impact

In order to reduce the viscosity of crude oil for transport, we often use the way of heating delivery for high pour point, high wax, and high viscosity oil. Crude oil at high temperature, through long-distance transmission, the temperature and pressure changes on the piping stress greater impact. In this paper, in order to explore the main factor of hot oil pipeline stress and the location of key points, we build the XX hot oil pipeline stress analysis model used CAESAR II software, analysis of the impact of changes in temperature and pressure on piping stress when hot oil pipeline running, draw hot oil pipeline stress distribution, clearly identifies the location of key points of stress concentration, and we have come to that temperature is a major factor in generating pipe stress.

scholarly journals Testing of Confining Pressure Impacton Explosion Energy of Explosive Materials

2017 ◽  
Vol 62 (2) ◽  
pp. 385-396 ◽  
Author(s):  
Jan Drzewiecki ◽  
Jacek Myszkowski ◽  
Andrzej Pytlik ◽  
Mateusz Pytlik
Keyword(s):  
Occupational Safety ◽  
Initial Pressure ◽  
Confining Pressure ◽  
Hard Coal ◽  
Test Results ◽  
Explosive Materials ◽  
Hard Coal Mining ◽  
Explosive Charges ◽  
Pressure Changes ◽  
The Impact

Abstract This paper presents the results of testing the explosion effects of two explosive charges placed in an environment with specified values of confining pressure. The aim of this study is to determine the impact of variable environmental conditions on the suitability of particular explosives for their use in the prevention of natural hazards in hard coal mining. The research results will contribute to improving the efficiency of currently adopted technologies of natural hazard prevention and aid in raising the level of occupational safety. To carry out the subject matter measurements, a special test stand was constructed which allows the value of the initial pressure inside the chamber, which constitutes its integral part, to be altered before the detonation of the charge being tested. The obtained characteristics of the pressure changes during the explosion of the analysed charge helped to identify the work (energy) which was produced during the process. The test results are a valuable source of information, opening up new possibilities for the use of explosives, the development of innovative solutions for the construction of explosive charges and their initiation.

scholarly journals Ground Pressure Changes Caused by MHT 8002HV Crawler Harvester Chassis

2021 ◽  
Vol 42 (2) ◽  
Author(s):  
Mariusz Kormanek ◽  
Jiří Dvořák
Keyword(s):  
Longitudinal Axis ◽  
Mountain Forest ◽  
Ground Contact ◽  
The Czech Republic ◽  
Active Length ◽  
Ground Pressure ◽  
Pressure Changes ◽  
The Impact ◽  
Contact Pressures ◽  
Made In

Ground contact pressures exerted by elements of the machine chassis on the ground in the forest are associated with the machine impact on the soil during its operation. In the case of a crawler system, determining the ground contact pressure appears simple, which is not entirely true. The aim of the study was to analyze the loads on the ground (forest soil) exerted by the MHT 8002HV crawler harvester chassis. The measurements were made in Forest School Enterprise in Kostelec nad Černými Lesy, Central Bohemia Region in the Czech Republic, on brown soil made of clay on stony formations, fresh mixed mountain forest (FMMF), with the use of a hydraulic scale when extending the harvester crane forward along and perpendicular to the longitudinal axis of the machine. The calculations were carried out with a simulated load of the crane on the tree in question, assuming that the impact on the ground of the crawler system is heterogeneous and that the point impact comes from the crawler support wheels. As it was shown, the average ground contact pressures under the crawler track of the analyzed harvester generally do not exceed 70 kPa. The crane extension with a simulated load, which would have caused the crawler track to act on the ground with an average pressure exceeding 70 kPa, was limited by machine stability. On the other hand, high ground contact pressures may occur under a more loaded section of the crawler track if the active length of the crawler track is shortened. As it was shown in the case of a weak track tension, the course of ground contact pressures exerted on the soil deviates from the assumed usually homogeneous impact over the entire length of the crawler.

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