Analysis of Hydrogen Sulfide Impact From Sour Gas Well Blowout in Offshore Platform

2010 ◽  
Author(s):  
Yuan Zhu ◽  
Guo-ming Chen ◽  
Hai-fa Deng
Keyword(s):  
Hydrogen Sulfide ◽  
Good Practice ◽  
Offshore Platform ◽  
Potential Hazard ◽  
Gas Well ◽  
Gas Leakage ◽  
Hazard Zone ◽  
Spatial Environment ◽  
Blowout Preventer ◽  
Sour Gas

Several sour gas leakage accidents have occurred in the offshore platform during the past decades, such as the Kab 121 platform in 2007, which caused serious consequences mainly resulting from the lethal toxicity of hydrogen sulfide (H2S). Under the threat of H2S, it is a challenge to exploit resource in the sour gas filed. Especially during the drilling operation, an abrupt blowout or kick could bring huge amount of H2S, envelop the platform and disperse in the cabins. The present paper is aimed at introducing our analysis of H2S dispersion both in the outer deck and inner mud treatment cabin so as to fully assess the potential poisoning during well blowout. The method we chosen was computational fluid dynamics according to the spatial environment characteristics of the offshore platform. First, we drew a comparison between accident consequences deriving from the wellhead configurations of an opened bell nipple and a sealed rotary blowout preventer (BOP) in the outer deck under various wind directions and speeds. The instantaneous concentrations and hazard zone distributions show that the second configuration is much better from the view of accident control. And the accident severity is much lower when the wind blows from the larboard, not from the prow for both configurations. As a result, the potential hazard zone would not envelop the entire platform with suitable platform position and arrangements of the mud return ditch, accommodation, helicopter deck et al. Then, the simulations of H2S dispersion in the mud treatment cabin were conducted in case of the closed outlet doors, opened outlet doors and sealed cabin with air ventilator working. An immediately dangerous to life level may come up in a short break with the door closed. In such a dangerous situation, H2S can only be made to disperse to other areas through the opened door or effectively ventilated away by means of a ventilator. It is a good practice to isolate the cabins with the potential H2S leakage and install ventilator. And a simple model was proposed to calculate the working time for the ventilator.

The Performance of Zirconium Alloys in Sulfide Solutions

CORROSION ◽  
1982 ◽  
Vol 38 (12) ◽  
pp. 615-620 ◽  
Author(s):  
Te-Lin Yau
Keyword(s):  
Hydrogen Sulfide ◽  
Stress Corrosion Cracking ◽  
Constant Strain Rate ◽  
Zirconium Alloys ◽  
Test Methods ◽  
Sustained Load ◽  
General Corrosion ◽  
Test Results ◽  
Gas Well ◽  
Sour Gas

Abstract Zirconium Grades R 60702, R 60704, and R 60705 were investigated for deep sour gas well applications. Test methods include autoclave, constant strain, sustained load, and constant strain rate techniques. Test results indicate that these alloys have excellent resistance to general corrosion and to stress corrosion cracking in sulfide environments. No cracking was detected in all grades of zirconium in 5% NaCl + 0.5% CH3COOH + saturated H2S at room and boiling temperatures. Hydrogen sulfide seems to play a neutral role in the corrosion reactions of zirconium because of zirconium's low affinity for sulfur.

Deep Workover Challenges of an HP/HT Sour Gas Well - Case History of Mutriba 12

2011 ◽  
Author(s):  
Mohammed Jasem Al-Saeedi ◽  
Fayez Abdulrahman Al Fayez ◽  
Dakhil Rasheed Al Enezi ◽  
mahesh sounderrajan ◽  
Mishary Najeeb Al-Mudhaf ◽  
...  
Keyword(s):  
Case History ◽  
Gas Well ◽  
History Of ◽  
Sour Gas

Turbodrill Bottomhole Assembly and Real-Time Data Improve Through-Tubing Coiled-Tubing Drilling Operations in Sour Gas Well

2015 ◽  
Author(s):  
A. Ebrahimi ◽  
P. J. Schermer ◽  
W. Jelinek ◽  
D. Pommier ◽  
S. Pfeil ◽  
...  
Keyword(s):  
Real Time ◽  
Time Data ◽  
Gas Well ◽  
Coiled Tubing ◽  
Real Time Data ◽  
Drilling Operations ◽  
Sour Gas

Effects of Perforated Flow Tube on the Flow Field of a Blowout Well

SPE Journal ◽  
2016 ◽  
Vol 21 (04) ◽  
pp. 1470-1476 ◽  
Author(s):  
Ebrahim Hajidavalloo ◽  
Saeed Alidadi Dehkohneh
Keyword(s):  
Flow Field ◽  
Flow Tube ◽  
Gas Well ◽  
Safety Measures ◽  
Team Members ◽  
Well Control ◽  
Blowout Preventer ◽  
New Type ◽  
Oil Gas ◽  
Simple Flow

Summary When a blowout oil/gas well catches fire, usually a flow tube is used to detach the fire from the wellhead and provide appropriate conditions for operating team members to approach the well and install the blowout-preventer (BOP) cap. Using the flow tube above the wellhead creates powerful suction around the tube that may jeopardize the safety of crew members. To reduce the power of suction around the well, a new perforated flow tube instead of simple flow tube was introduced. To understand the effect of this new type of flow tube, modeling and simulation of the flow field around the blowout well were performed for both simple and perforated types of flow tube with Fluent 6.3.26 (2003) and Gambit 2.3.16 (2003) softwares. Different parameters around the well mouth were compared in both designs. The results showed that using the perforated flow tube decreases the vacuum around the well by 33% compared with the simple flow tubes. Thus, application of the perforated flow tube can be recommended in well-control operations for safety measures.

scholarly journals Viscoelastic behavior of a casing material and its utilization in premium connections in high-temperature gas wells

2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881745 ◽  
Author(s):  
Ying Zhang ◽  
Zhanghua Lian ◽  
Mi Zhou ◽  
Tiejun Lin
Keyword(s):  
High Temperature ◽  
Contact Pressure ◽  
Viscoelastic Model ◽  
Viscoelastic Behavior ◽  
Element Model ◽  
Gas Production ◽  
Prony Series ◽  
Gas Well ◽  
Gas Leakage ◽  
High Temperature Gas

At the high or extra-high temperatures in a natural gas oilfield, where the premium connection is employed by casing, gas leakage in the wellbore is always detected after several years of gas production. As the viscoelastic material’s mechanical properties change with time and temperature, the relaxation of the contact pressure on the connection sealing surface is the main reason for the gas leakage in the high-temperature gas well. In this article, tension-creep experiments were conducted. Furthermore, a constitutive model of the casing material was established by the Prony series method. Moreover, the Prony series’ shift factor was calculated to study the thermo-rheological behavior of the casing material ranging from 120°C to 300°C. A linear viscoelastic model was implemented in ABAQUS, and the simulation results are compared to our experimental data to validate the methodology. Finally, the viscoelastic finite element model is applied to predict the relaxation of contact pressure on the premium connections’ sealing surface versus time under different temperatures. And, the ratio of the design contact pressure and the intending gas sealing pressure is recommended for avoiding the premium connections failure in the high-temperature gas well.

Resin Squeeze Operation to Successfully Seal Micro-Channels and Eliminate Sustained Casing Pressure of a Sour Gas Well

2021 ◽  
Author(s):  
Ying Wang ◽  
Xin Zheng ◽  
Li Li ◽  
Jianbo Yuan ◽  
Minh Vo ◽  
...  
Keyword(s):  
Good Condition ◽  
Water Injection ◽  
Injection Rate ◽  
Gas Well ◽  
Wellhead Pressure ◽  
Low Viscosity ◽  
Resin Injection ◽  
Micro Channels ◽  
Sustained Casing Pressure ◽  
Sour Gas

Abstract This paper describes the successful resin squeeze operation to seal off a micro-annulus between the 7" and 9-5/8" casings on a sour gas well located in Sichuan Basin, China. Integrated plug and abandonment were also essential to eliminate the risk of potential H2S exposure presented to the residents around this area. Resin, as a new alternative sealing technology, was technically evaluated, laboratory tested, and then chosen for squeezing into a micro-annulus to stop gas migration for its solids-free and low-viscosity properties compared to a conventional cement. The squeeze job was designed by taking the casing yield strength as the pressure limit (Confirmed by caliper log the casing was in good condition) and determining the resin pumping volume based on estimated resin squeeze volume and the remaining resin plug length. A "Braden-head" squeeze method was selected considering the low injection rate observed during the water injection test. Both stage-up and stage down squeezing techniques (hesitation squeeze of increasing and decreasing wellhead pressure stage by stage) were performed to maximize the injected volume of the resin sealant. A total of 800 L of 9.16 lb/gal resin was placed into a 4 ft milled interval, and 50 L were successfully squeezed into the 7" × 9-5/8" casing annulus. An operational learning was that resin injection is greatly improved during the stage-down process while keeping the casing annulus open. Evidence that the micro-annulus leak path had been sealed was an observation of 0 psi on the 7" × 9-5/8" casing annulus after resin fully set. The method of locating the optimal spot to squeeze resin involved noise logging to analyze for a potential gas source in the annulus. The post job results confirmed that resin acts effectively as an annular barrier in the repair of gas leaks in the small volume situations where micro-annulus exists in the cement sheath. For large voids such as inside 7" casing, a combination of cement plug plus mechanical barrier is recommended to be placed directly above resin plugs to complete permanent plug and abandonment of the wellbore.

Case History: Hydraulic Workover Unit Utilized to Recover Highly Corroded 30-Year Old Completion from a Live Gas Well in the United Arab Emirates

2021 ◽  
Author(s):  
Aurelio Marcano Avila ◽  
Abimbola Raji ◽  
Renny Ottolina ◽  
Jose Jimenez
Keyword(s):  
United Arab Emirates ◽  
Controlled Environment ◽  
Successful Operation ◽  
Time Saving ◽  
Gas Well ◽  
Overall Design ◽  
Job Preparation ◽  
Blowout Preventer ◽  
Potential Pressure ◽  
Production Tubing

Abstract In the UAE, an Operator needed to perform a completion change out in a gas well, where the existing completion has been installed for over 30 years. Logging operations had revealed several leaks point in the production tubing due to corrosion. To rectify the situation, a Hydraulic Workover (HWO) Unit was proposed integrating a punch ram in the Blowout Preventer (BOP) Configuration to manage the bleed off of potential pressure trapped between the isolated sections of the completion at surface. This document describes how the highly corroded completion tubing with eleven retrievable plugs set in a live gas well was recovered. The HWO Unit was modified so that one of the cavities in the BOP stack was dressed with customized punch rams for five inch pipe, with the objective of allowing control of any potential leaks due to plug failure. The pressure relief operation could then be completed by means of punching the tubing in the controlled environment that a Stripping BOP Stack provides. This paper compiles the details of the BOP configuration and operating procedures to recover the completion by stripping out of the well and operating the punch rams with the snubbing unit. This includes the pre-job preparation required for a successful operation and the overall design with where to locate the collars and plugs for an accurate punch, and how to confirm that the plugs are holding the pressure to continue retrieving the next completion section. In the end, a safe operation was completed with zero incidents or down time allowing the intervention to continue to the next stage of recompleting the well and putting it back to production. The customer was able to get the well back to production with an alternative solution to what was initially considered, representing a significant cost and time saving.

Solid Management Optimization for Offshore Big Bore HP/HT Sour Gas Well Cleanup

2020 ◽  
Author(s):  
Ardian Nengkoda ◽  
Abdallah Qahtani ◽  
Sami Logan ◽  
Mostafa Youssef ◽  
Alastair Sinker
Keyword(s):  
Gas Well ◽  
Management Optimization ◽  
Sour Gas

scholarly journals First-principles microkinetic study of methane and hydrogen sulfide catalytic conversion to methanethiol/dimethyl sulfide on Mo6S8 clusters: activity/selectivity of different promoters

2019 ◽  
Vol 9 (17) ◽  
pp. 4573-4580 ◽  
Author(s):  
Adam A. Arvidsson ◽  
William Taifan ◽  
Anders Hellman ◽  
Jonas Baltrusaitis
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Sulfide ◽  
Natural Gas ◽  
First Principles ◽  
Dimethyl Sulfide ◽  
Large Fraction ◽  
Catalytic Conversion ◽  
Sour Gas

A large fraction of the global natural gas reserves is in the form of sour gas, i.e. contains hydrogen sulfide (H2S) and carbon dioxide (CO2), and needs to be sweetened before utilization.

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