Best Practices While Testing Sour GAS Wells

2021 ◽  
Author(s):  
Mubashir Mubashir Ahmad ◽  
Fawad Zain Yousfi ◽  
Mohamed Albadi ◽  
Mohamed Baslaib ◽  
Shamsa Alhouqani ◽  
...  
Keyword(s):  
Gas Production ◽  
Civil Defense ◽  
Advanced Technology ◽  
Stress Cracking ◽  
Well Completion ◽  
Technical Requirements ◽  
Energy Needs ◽  
Zonal Isolation ◽  
Weak Points ◽  
Sour Gas

Abstract Objectives/Scope The development of Abu Dhabi's sour gas is not without its challenges. Deep drilling in some fields presents its own set of difficulties due to high temp and pressures coupled with +30% H2S and +10% CO2. Handling of these corrosive reservoir fluids both while drilling and then testing, requires deploying advanced technology to meet the specific requirements of these reservoirs, along with the infrastructure necessary to handle the toxic and corrosive products while testing in a brown field safely. Methods, Procedures, Process Developing local sour gas production is seen as the answer to resolve the ever growing energy needs for UAE but the technical requirements for the project is stretching the limits of the industry. Results, Observations, Conclusions What did we do different: Developed and implemented specific HSE procedures and SIMOPS due to close proximity with major populated facilities which could not be shut-down during the testing period. Conducted multiple audits and drills with the local authorities including Civil Defense and local Police. Additional 3rd part supervision was provided to ensure all personal are complying with the policy and procedures developed. Installed 2 green burners and 2 vertical 90 ft flare stacks at 180 degrees. This was to cater for the changing wind directions for continuous operations and as back ups. CCTV monitoring for green burners / flare stacks was conducted although this was a rigless operation 3 circles of H2S detectors and sensors were placed around the testing area and the flare stakes and green burners to detect any H2S gas. (Covering all 360° directions). Blowdown/Depressurization valve was installed at separator, storage tanks apart from Automatic and manual shutdown system upon H2S detection Installed Optic Fiber cable from wellhead to the main control room for monitoring purposes All piping connections used were flange-to-flange as welded joints could have caused stress cracking on the weak points For Sour well operation, used fully cladded X-mass tree & Inconel well completion Considered setting of compatible TTBP (Thru Tubing Bridge Plug) for staked reservoirs zonal isolation Instead of coil tubing cement plug for accurate depth calculations. Arranged Special chemical for any scale cleanout for handling of elemental Sulphur. Arab zones were stimulated with specialized acid recipe developed exclusively for this temperature, pressure and sour conditions downhole. Bottom hole measurements were recorded successfully and all the necessary data was acquired. Novel/Additive Information This paper highlights the major challenges identified and mitigated to test and produce the highly sour HPHT gas during the appraisal program complying with ADNOC 100% HSE in a brown field without disturbing the other major operations being performed in the vicinity.

A Dynamic Workflow of Well Health Issue Prediction – Sulfur Deposition

2021 ◽  
Author(s):  
Bashirul Haq
Keyword(s):  
Material Balance ◽  
Gas Production ◽  
Health Issue ◽  
Sulfur Deposition ◽  
Gas Reservoirs ◽  
Gas Field ◽  
Actual Performance ◽  
Sulphur Deposition ◽  
Balance Analysis ◽  
Sour Gas

Abstract Sour gas reservoirs are vital sources for natural gas production. Sulphur deposition in the reservoir reduces a considerable amount of gas production due to permeability reduction. Consequently, well health monitoring and early prediction of Sulphur deposition are crucial for effective gas production from a sour gas reservoir. Dynamic gas material balance analysis is a useful technique in calculating gas initially in place utilizing the flowing wellhead or bottom hole pressures and rates during the well's lifetime. The approach did not apply to monitor a producing gas's health well and detect Sulphur deposition. This work aims to (i) modify dynamic gas material balance equation by adding the Sulphur deposition term, (ii) build a model to predict and validate the issue utilizing the modified equation. A unique form of the flowing material balance is developed by including Sulphur residue term. The curve fitting tool and modified flowing gas material balance are applied to predict well-expected behaviour. The variation between expected and actual performance indicates the health issue of a well. Initial, individual components of the model are tested. Then the model is validated with the known values. The workflow is applied to active gas field and correctly detected the health issue. The novel workflow can accurately predict Sulphur evidence. Besides,the workflow can notify the production engineers to take corrective measures about the subject. Keywords: Sulfur deposition, Dynamic gas material balance analysis, Workflow

scholarly journals Effects of Formation Dip on Gas Production from Unconfined Marine Hydrate-Bearing Sediments through Depressurization

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yilong Yuan ◽  
Tianfu Xu ◽  
Yingli Xia ◽  
Xin Xin
Keyword(s):  
Large Scale ◽  
Horizontal Well ◽  
Field Measurements ◽  
Production Method ◽  
Geological Structure ◽  
Horizontal Distribution ◽  
Gas Production ◽  
Well Completion ◽  
Hydrate Reservoir ◽  
Hydrate Bearing Sediments

The effects of geologic conditions and production methods on gas production from hydrate-bearing sediments (HBS) have been widely investigated. The reservoir was usually treated as horizontal distribution, whereas the sloping reservoir was not considered. In fact, most strata have gradients because of the effects of geological structure and diagenesis. In this study, based on currently available geological data from field measurements in Shenhu area of the South China Sea, the effects of formation dip on gas production were investigated through depressurization using a horizontal well. The modeling results indicate that the strategy of horizontal well is an effective production method from the unconfined Class 2 HBS. The predicted cumulative volume of methane produced at the 1000 m horizontal well was 4.51 × 107 ST m3 over 5-year period. The hydrate dissociation behavior of sloping formation is sensitive to changes in the reservoir pressure. As in unconfined marine hydrate reservoir, the sloping formation is not conducive to free methane gas recovery, which results in more dissolved methane produced at the horizontal well. The obvious issue for this challenging target is relatively low exploitation efficiency of methane because of the recovery of very large volumes of water. Consequently, the development of the favorable well completion method to prevent water production is significantly important for realizing large scale hydrate exploitation in the future.

Fuzzy Sensitivity Analysis in the Context of Dimensional Management

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Thomas Oberleiter ◽  
Björn Heling ◽  
Benjamin Schleich ◽  
Kai Willner ◽  
Sandro Wartzack
Keyword(s):  
Tolerance Analysis ◽  
Design Stage ◽  
Special Focus ◽  
Total System ◽  
Early Design Stage ◽  
Technical Requirements ◽  
Geometric Deviations ◽  
Weak Points ◽  
Dimensional Management ◽  
The Impact

Real components always deviate from their ideal dimensions. This makes every component, even a serial production, unique. Although they look the same, differences can always be observed due to different scattering factors and variations in the manufacturing process. All these factors inevitably lead to parts that deviate from their ideal shape and, therefore, have different properties than the ideal component. Changing properties can lead to major problems or even failure during operation. It is necessary to specify the permitted deviations to ensure that every single product nevertheless meets its technical requirements. Furthermore, it is necessary to estimate the consequences of the permitted deviations, which is done via tolerance analysis. During this process, components are assembled virtually and varied with the uncertainties specified by the tolerances. A variation simulation is one opportunity to calculate these effects for geometric deviations. Since tolerance analysis enables engineers to identify weak points in an early design stage, it is important to know the contribution that every single tolerance has on a certain quality-relevant characteristic, to restrict or increase the correct tolerances. In this paper, a fuzzy-based method to calculate the sensitivity is introduced and compared with the commonly used extended Fourier amplitude sensitivity test (EFAST) method. Special focus of this work is the differentiation of the sensitivity for the total system and the sensitivities for the subsystems defined by the α-cuts of the fuzzy numbers. It discusses the impact of the number of evaluations and nonlinearity on sensitivity for EFAST and the fuzzy-based method.

Laboratory-Scale Investigation of the Utilisation of Multiple Flat-Fan Nozzles in Descaling Petroleum Production Tubing

2021 ◽  
Author(s):  
Kabir Hasan Yar'Adua ◽  
Idoko Job John ◽  
Abubakar Jibril Abbas ◽  
Salihu M. Suleiman ◽  
Abdullahi A. Ahmadu ◽  
...  
Keyword(s):  
High Pressure ◽  
Oil And Gas ◽  
Gas Production ◽  
Oil And Gas Production ◽  
Scale Removal ◽  
Petroleum Production ◽  
Well Completion ◽  
Water Jets ◽  
Well Integrity ◽  
Injection Pressures

Abstract Despite the recent wide embrace of mechanical descaling approaches for cleaning scales in petroleum production tubings and similar conduits with the use of high-pressure (HP) water jets, the process is still associated with downhole backpressure and well integrity challenges. While the introduction of sterling beads to replace sand particles in the water recorded high successes in maintaining well completion integrity after scale removal in some recent applications of this technique, it is, unfortunately, still not without questions of environmental degradation. Furthermore, the single nozzle, solids-free, aerated jetting descaling technique – recently published widely – is categorized with low scale surface area of contact, low descaling efficiency and subsequent high descaling rig time. The modifications to mechanical descaling techniques proposed in this work involve the use of three high-pressure flat fan nozzles of varying nozzles arrangements, standoff distances and injection pressures to remove soft scale deposits in oil and gas production tubings and similar circular conduits. This experiment provides further insights into the removal of paraffin scales of various shapes at different descaling conditions of injection pressures, stand-off distances and nozzle arrangements with the use of freshwater. The results obtained from this study also show consistency with findings from earlier works on the same subject.

Failure Along Spiral Welds in Gas Pipeline

2016 ◽  
Author(s):  
Saleh Al-Sulaiman ◽  
Shabbir Safri ◽  
Abdul Salam ◽  
Chi Lee
Keyword(s):  
Stress Measurement ◽  
Gas Pipeline ◽  
Gas Oil ◽  
Stress Cracking ◽  
Failure Investigation ◽  
Oil Export ◽  
Sulfide Stress ◽  
Sulfide Stress Cracking ◽  
Operational Constraints ◽  
Sour Gas

A 16 km. long, 18” Gas pipeline (HP055) was in service to transport High Pressure Gas from an oil gathering center in West Kuwait (WK) area since 2001. The Pipeline carried wet sour gas. It was inspected in 2008 using high resolution MFL-ILI tool. No significant corrosion was found. In late 2012, a leak developed in the pipeline. The leak was due to a crack along a spiral weld on the bottom. Inspection during repairs revealed severe internal pitting on the bottom. The pipeline continued to leak several times in the next year, eventually resulting in decommissioning of the pipeline. Another ILI could not be carried out due to operational constraints and frequent leaks. The Pipeline was critical in the operation of the oil gathering center, and the loss of it severally affected the gas/oil export target and the flaring reduction commitment. An internal failure investigation was inconclusive, though indicating possibility of sulfide stress cracking. The failure investigation work was then entrusted to TWI, UK. A failed section of the pipeline was sent to their facilities and various tests including Chemical analysis, tensile test, residual stress measurement, SSC/HIC test, microstructure analysis, and analysis of corrosion products were carried out. The outcome of the tests and conclusion was very surprising. This paper describes in detail the leaks, inspection of leak locations, and the failure investigation findings and conclusions.

Research and Application of Material Corrosion Prevention Technology in the Completed well System for Sour Gas well

2013 ◽  
Vol 712-715 ◽  
pp. 1096-1099
Author(s):  
Ling Feng Li
Keyword(s):  
Steel Corrosion ◽  
Gas Production ◽  
Corrosion Prevention ◽  
Gas Reservoirs ◽  
Gas Field ◽  
Gas Well ◽  
Corrosion Resistant Alloy ◽  
System Life ◽  
Sour Gas

For natural gas well in sour gas reservoirs, very serious corrosion in the completed well system is an important factor of gas production system life. In order to ensure the long-term development of gas wells, this paper mainly introduces material corrosion prevention technology in the completed well system, such as corrosion-resistant alloy steel corrosion control technology, bimetallic combination tubing, corrosion inhibitor technology and so on. By taking LJ Gas Field as an example, this paper introduces the material corrosion prevention technology in the completed well system in LJ Gas Field. For application in the completed well system in LJ Gas Field, the technology above have good performance of corrosion resistance.

Research on Tubing and Casing Corrosion in Sour Gas Reservoirs and Corrosion-Resistant Material Selection

2013 ◽  
Vol 690-693 ◽  
pp. 1516-1519
Author(s):  
Ling Feng Li
Keyword(s):  
Material Selection ◽  
Gas Production ◽  
Resistant Material ◽  
Gas Reservoirs ◽  
Gas Well ◽  
Corrosion Resistant ◽  
System Life ◽  
Sour Gas ◽  
Selection Of

For natural gas well in sour gas reservoirs, very serious corrosion in the gas well string is an important factor of gas production system life. In order to ensure the long-term development of gas wells, this paper mainly introduces the tubing and casing corrosion in sour gas reservoirs, corrosion-resistant material selection of tubing and casing in sour gas reservoirs and proposes the optimization idea and technique of tubing material selection.. By taking W 63 well as an example, this paper optimizes the material selection of production casing for W 63 well. For application, the optimal materials of gas well string in W 63 well have good performance of corrosion resistance.

Regional parametric sensitivity analysis of Walloon Subgroup CSG production

2017 ◽  
Vol 57 (1) ◽  
pp. 277
Author(s):  
Daren Shields ◽  
Fengde Zhou ◽  
Joan Esterle
Keyword(s):  
Gas Production ◽  
Gas Content ◽  
Project Schedule ◽  
Coal Seam Gas ◽  
Simulation Experiments ◽  
Reservoir Performance ◽  
Well Completion ◽  
Reservoir Models ◽  
Single Well ◽  
Eastern Edge

Following two decades of intensive exploration, coal seam gas (CSG) production in the Surat Basin has begun to dramatically increase to meet the capacity of three newly completed CSG to liquefied natural gas (LNG) export projects. As the industry’s focus shifts from appraisal to exploitation, the production forecasts underpinning these LNG projects are being tested. In some cases predicted reservoir performance is found to be invalidated by observed production data, a condition that may require costly amendments to project schedule and scope. The deviation between actual and predicted reservoir performance can often be attributed to an incomplete understanding of parametric uncertainties present in static or dynamic reservoir models. To address this limitation, this study aims to explore the parametric controls upon CSG production behaviours with a series of simulation experiments. Distributions of reservoir parameters were compiled from 152 open-source well completion reports available in three areas along the eastern edge of the Surat Basin. These distributions were validated and then sampled to extract representative ranges for subsurface factors including gas content, permeability, net coal thickness, Langmuir pressure, Langmuir volume and drainage area. These inputs were used to construct single well radial models, which were then simulated to generate predictions of monthly and cumulative produced fluid volumes. The results of this study indicate that net coal thickness and lateral coal connectivity are the most sensitive factors with respect to cumulative gas production, while permeability was the single most influential parameter affecting the rate of gas production.

A Method for the Verification of Subsea Equipment Subject to Hydrogen Induced Stress Cracking

2010 ◽  
Author(s):  
Michelangelo Fabbrizzi ◽  
Paolo Di Sisto ◽  
Roberto Merlo
Keyword(s):  
Oil And Gas ◽  
Production Systems ◽  
Local Stress ◽  
Gas Production ◽  
Stress And Strain ◽  
3D Analysis ◽  
Oil And Gas Production ◽  
Safety Issues ◽  
Stress Cracking ◽  
Induced Stress

Subsea oil and gas production systems can be subject to Hydrogen Induced Stress Cracking (“HISC”) depending on the material, cathodic protection and other factors. A failure in this kind of systems can lead to safety issues as well as environmental hazards and high repair costs. The analysis of recent failures has led to the recognition of HISC as a very important issue related to local stress and strain. This has necessitated the extensive use of Finite Elements Methods for the analysis of all system components. Since HISC is a recent issue, there are very few cases of such assessments reported in the literature. This paper is based on the assessment of the susceptibility of subsea piping manifolds of Duplex stainless steel to Hydrogen Induced Stress Cracking, which was conducted during the Skarv project by General Electric Oil & Gas. A variety of cases consisting of different loads and configurations were considered to give a broad assessment using a recently developed code (DNV-RP-F112-October2008). This work has led to the development of a set of procedures and models for the assessment of the entire system which is described in the current paper. The proposed methodology is useful for both design purposes and also for the verification of parts, which, if found to be non-compliant, would require redesign. In general, parts that were determined to be non-compliant using a linear assessment were found to be compliant through non-linear analysis, in fact 3D plastic analysis leads to a redistribution of stress and strain and hence, to lower values. “Cold creep” was not considered since the levels of stress and strain were considered to be low enough to avoid this phenomenon. As a consequence of this experience, a new methodology was developed, which is able to speed up the analysis process and to predict local stresses from only pipe elements. The latter permits the use of a linear assessment for bends, T junctions and weldolet even with misalignment and erosion, avoiding the need to perform 3D analysis. The second part of the paper describes this method.

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