FEP Based Model Development for Assessing Well Integrity Risk Related to CO2 Storage in Central Luconia Gas Fields in Sarawak

2021 ◽  
Author(s):  
Parimal A. Patil ◽  
Prasanna Chidambaram ◽  
M Syafeeq Bin Ebining Amir ◽  
Pankaj K. Tiwari ◽  
Debasis P. Das ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Co2 Storage ◽  
Gas Reservoirs ◽  
Well Integrity ◽  
Depleted Gas Reservoirs ◽  
Integrity Risk ◽  
Central Luconia ◽  
Gas Fields ◽  
Cement Plug

Abstract Underground storage of CO2 in depleted gas reservoirs is a greenhouse gas reduction technique that significantly reduces CO2 released into the atmosphere. Three major depleted gas reservoirs in Central Luconia gas field, located offshore Sarawak, possess good geological characteristics needed to ensure long-term security for CO2 stored deep underground. Long-term integrity of all the wells drilled in these gas fields must be ensured in order to successfully keep the CO2 stored for decades/centuries into the future. Well integrity is often defined as the ability to contain fluids without significant leakage through the project lifecycle. In order to analyze the risk associated with all 38 drilled wells, that includes 11 plugged and abandoned (P&A) wells and 27 active wells, probabilistic risk assessment approach has been developed. This approach uses various leakage scenarios, that includes features, events, and processes (FEP). A P&A well in a depleted reservoir is a very complex system in order to assess the loss of containment as several scenarios and parameters associated to those scenarios are difficult to estimate. Based on the available data of P&A wells, a well has been selected for this study. All the barriers in the example well have been identified and properties associated with those barriers are defined in order to estimate the possible leakage pathways through the identified barriers within that well. Detailed mathematical models are provided for estimating CO2 leakage from reservoir to the surface through all possible leakage pathways. Sensitivity analysis has been carried out for critical parameters such as cement permeability, and length of cement plug, in order to assess the containment ability of that well and understand its impact on overall well integrity. Sensitivity analysis shows that permeability of the cement in the annulus, and length of cement plug in the wellbore along with pressure differential can be used as critical set of parameters to assess the risk associated with all wells in these three fields. Well integrity is defined as the ability of the composite system (cemented casings string) in the well to contain fluids without significant leakage from underground reservoir up to surface. It has been recognized as a key performance factor determining the viability of any CCS project. This is the first attempt in assessing Well Integrity risk related to CO2 storage in Central Luconia Gas Fields in Sarawak. The wells have been looked individually in order to make sure that integrity is maintained, and CO2 is contained underground for years to come.

Safeguarding CO2 Storage by Restoring Well Integrity Using Leakage Rate Modeling LRM along Wellbore in Depleted Gas Fields Offshore Sarawak

2021 ◽  
Author(s):  
Parimal A. Patil ◽  
Prasanna Chidambaram ◽  
M Syafeeq B. Ebining Amir ◽  
Pankaj K. Tiwari ◽  
Mahesh S. Picha ◽  
...  
Keyword(s):  
Action Plan ◽  
Co2 Storage ◽  
Leakage Rate ◽  
Dispersion Modeling ◽  
Storage Site ◽  
Remedial Action ◽  
Well Integrity ◽  
Gas Fields ◽  
Remedial Action Plan

Abstract Ensuring long-term integrity of existing plugged and abandoned (P&A) and active wells that penetrated the selected CO2 storage reservoir is the key to reduce leakage risks along the wellpath for long-term containment sustainability. Restoring the well integrity, when required, will safeguard CO2 containment for decades. Well integrity is often defined as the ability to contain fluids with minimum to nil leakage throughout the project lifecycle. With a view to develop depleted gas fields as CO2 storage sites in offshore Sarawak, it is vital to determine the complexity involved in restoring the integrity of these P&A wells as well as the development wells. Leakage Rate Modeling (LRM) was performed to identify and evaluate the associated risks for designing the remedial action plan to safeguard CO2 storage site. The P&A wells in the identified depleted gas fields were drilled 35–45 years ago and were not designed to withstand high CO2 concentration downhole conditions. Corrosive-Resistant Alloy (CRA) tubulars and CO2 resistant cement were not used during well construction and downhole pressure and temperature conditions may have further degraded the material strength and elevated the corrosion susceptibility. As a proof of concept, single well was selected to assess the loss of containment along the wellbore and to determine the complexity in resorting the well integrity, multiple scenarios were considered in LRM and composite structure and barrier parameters were assigned to estimate possible leakage pathways. Detailed numerical models were simulated for estimating leakage from reservoir to the surface through possible leakage pathways. Risks were identified and remedial action plan was designed for restoring well integrity. Post remedial plan covers Marine CO2 dispersion modeling to design comprehensive monitoring and mitigation plan for potential CO2 leakage in the marine environment. This study summarizes the unique challenge associated with estimating well integrity and re-entering existing P&A wells. Leakage rate modeling along these wells involves uncertainties but when carried out with realistic parameters, it can be used as a predicting tool to determine the nature and complexity of leakage. Integrating with site survey results for any indication of gas bubbling, decision can be made to restoring the well integrity. The paper outlines the detail strategic options to safeguard CO2 storage by restoring well integrity using LRM and integrating with marine CO2 dispersion modeling. Assessing well integrity of P&A wells on individual basis, risk is assessed and identified. Proper remedial actions are proposed accordingly. Quantification of all the uncertainties involved needs to be conducted that may affect long-term security of CO2 storage site.

CO2 Storage as Hydrate in Depleted Gas Reservoirs

2010 ◽  
Author(s):  
Olga Ye Zatsepina ◽  
Mehran Pooladi-Darvish
Keyword(s):  
Co2 Storage ◽  
Gas Reservoirs ◽  
Depleted Gas Reservoirs

Reservoir Characterization for Uncertainty Analysis and Its Impact on CO2 Injection and Sequestration in a Depleted Offshore Carbonate Gas Field

2021 ◽  
Author(s):  
Debasis P. Das ◽  
Parimal A. Patil ◽  
Pankaj K. Tiwari ◽  
Renato J Leite ◽  
Raj Deo Tewari
Keyword(s):  
Co2 Storage ◽  
Assessment Process ◽  
Rock Properties ◽  
Co2 Injection ◽  
Storage Site ◽  
Reservoir Pressure ◽  
Gas Field ◽  
Well Integrity ◽  
Seismic Anomalies

Abstract The emerging global climate change policies have necessitated the strategic need for prudent management of produced contaminants and, with cold flaring being no more the best option, Carbon Capture Utilization & Storage (CCUS) technology provides opportunity for development of high CO2 contaminant fields. A typical CO2 sequestration project comprises capturing CO2 by separating from produced hydrocarbons followed by injection of CO2 into deep geological formations for long term storage. While injection ofCO2 may continue over tens of years, the long-term containment needs to be ascertained for thousands of years. Several geological and geophysical factors along with the existingwells need to be evaluated to assess the potential risks for CO2 leakage that maychallenge the long-term containment. This study considers a depleted carbonate field located offshore Sarawak as a possible long-term CO2 storage site. Elements that may lead to possible leakage of CO2over time are the existing faults or fractures, development of new fractures/faults during injection, caprock failure due to pressures exceeding fracture pressure during/after injection and possible leakage through existing wells. The risk assessment process includes identification and mapping of faults and fracture networks, mapping of seals, evaluation of seismic anomalies and gas while drilling records, pore-pressure analysis, laboratory experiments for analyzing changes in geomechanical & geochemical rock properties and well integrity of existing wells. All these parameters are cross correlated, and qualitative risk categorization is carried out to determine the robustness of the reservoir for long term CO2 storage. The evaluation of available data indicates less frequent faulting occur only towards the flank with no seismic anomalies associated with them. Some seismic anomalies are observed at shallower levels, however their impact on the reservoir and overburden integrity is assessed to be minimum. There are four shale dominated formations mapped in the overburden section, which will act as potential seals. Estimated fracture pressures for the potential seals ranges between 6200-9280 psia for the deepest seal to 2910-4290 psia for the shallowest. Therefore,it is interpreted that if the post injection reservoir pressure is kept below the initial reservoir pressure of 4480 psia, it would not hold any threat to the caprock integrity.Leakage rate riskalong the existing wells was determined based on well log data. Well integrity check of legacywells helped identify two abandoned wells for rigorous remediation to restore their integrity. The subsurface risk analysis is critical to ascertain the long-term containment of injectedCO2. The integrated subsurface characterization and well integrity analysis approach adopted in this work can be applied to any other field/reservoir to validate its robustness for long-term CO2 injection and storage.

scholarly journals CO2 storage in depleted gas reservoirs: A study on the effect of residual gas saturation

Petroleum ◽  
2018 ◽  
Vol 4 (1) ◽  
pp. 95-107 ◽  
Author(s):  
Arshad Raza ◽  
Raoof Gholami ◽  
Reza Rezaee ◽  
Chua Han Bing ◽  
Ramasamy Nagarajan ◽  
...  
Keyword(s):  
Co2 Storage ◽  
Gas Reservoirs ◽  
Gas Saturation ◽  
Depleted Gas Reservoirs ◽  
Residual Gas ◽  
Residual Gas Saturation

scholarly journals Application of material balance methods to CO2 storage capacity estimation within selected depleted gas reservoirs

2017 ◽  
Vol 23 (3) ◽  
pp. 339-352 ◽  
Author(s):  
A. L. Clarke ◽  
J. Imber ◽  
R. J. Davies ◽  
J. van Hunen ◽  
S. E. Daniels ◽  
...  
Keyword(s):  
Storage Capacity ◽  
Co2 Storage ◽  
Material Balance ◽  
Capacity Estimation ◽  
Gas Reservoirs ◽  
Depleted Gas Reservoirs

Evaluation of the Petrel Sub-basin as a northern Australia CO2 store: future decarbonisation hub?

2020 ◽  
Vol 60 (2) ◽  
pp. 765
Author(s):  
Linda Stalker ◽  
David Dewhurst ◽  
Yanhua Zhang ◽  
Peter Schaubs ◽  
Ben Clennell ◽  
...  
Keyword(s):  
Natural Gas ◽  
Seismic Data ◽  
Co2 Storage ◽  
Northern Australia ◽  
Upward Migration ◽  
Collaborative Project ◽  
Potential Impact ◽  
Gas Fields ◽  
3D Seismic Data

The Northern Australia CO2 Store Project has extended investigations for safe, long-term containment of large volumes of CO2 (up to 100 million tonnes) to support liquefied natural gas and other industries in a decarbonised future. Most natural gas fields in the Petrel Sub-basin and the surrounding region have relatively high native CO2 content. This collaborative project improved storage characterisation, evaluated geomechanical risks and estimated engineering demands necessary to progress the concept to ‘prospect’ and ‘resource’. New data have significantly advanced the geological and structural understanding in the region, improving chrono- and litho-stratigraphic correlations, with new well ties across the basin. However, the re-mapping has thrown up new questions that require additional data (e.g. new stratigraphic wells, 3D seismic data) to address those knowledge gaps. Geomechanical modelling in the area has tested (to extreme levels) the potential impact of injection on faults in the area, further de-risking the likelihood of upward migration and leakage. The region could utilise an abundance of energy and feedstocks in the form of solar, natural gas, hydrogen and CO2 to become a future decarbonisation and industrial hub while managing major emissions with offshore CO2 storage.

Thermodynamic Pathways of CO2 Storage in Depleted Gas Reservoirs

2020 ◽  
Author(s):  
P. Kowollik ◽  
S. Khamnaeva ◽  
F. Vodopic ◽  
M. Kleczar ◽  
H. Alkan
Keyword(s):  
Co2 Storage ◽  
Gas Reservoirs ◽  
Depleted Gas Reservoirs

Robust Leakage Modeling for Plug and Abandonment Applications

2019 ◽  
Author(s):  
Mustafa Al Ramadan ◽  
Saeed Salehi ◽  
Catalin Teodoriu
Keyword(s):  
Oil And Gas ◽  
Pore Space ◽  
Differential Pressure ◽  
Cement Slurry ◽  
High Pressure And Temperature ◽  
Gas Leakage ◽  
Fluid Leakage ◽  
Well Integrity ◽  
Cement Plug

Abstract Oil and gas wells that require to be shut off forever, after depleting their reserves, need to be plugged and abandoned. Plug and Abandonment (P&A) operations induce many arduous challenges worldwide. The aim of P&A is to isolate and prevent fluid leakage in the wellbore in such a way that all fluids are contained in their formation for an undefined time. Failure of P&A in isolating and preventing fluid leakage can jeopardize the well integrity. Cement plugs that are used in this operation play a crucial role in maintaining the well integrity. Cement is considered as a porous medium that has an ultra-low permeability that can be achieved when some additives are used in the cement slurry to reduce its permeability and pore space. The cement plug may deteriorate with time under harsh downhole conditions, such as high pressure and temperature and exposure to different fluids. Cement plug deterioration will result in increasing the cement permeability or the overall permeability by creating channels or microannuli. In this study, several scenarios are presented for gas leakage through cement plugs. In these leakage scenarios, the differential pressure across the cement plug was varied. The aim of generating these scenarios is to investigate the current required cement plug length. In each scenario, four different permeability values were used to assess the risk associated with each value. In addition, the cement plug length was varied to investigate how the cement plug length is going to help ensure good well integrity. The leakage scenarios presented revealed that longer cement plugs have a longer leakage time. In addition, the results show an increase of leakage time as microannulus gap permeability decreases. Differential pressure exerted on the cement plug have a strong effect on the leakage time. To achieve a long term well integrity in P&A phase, an ultra-low permeable cement plug with excellent bonding, longer cement plug, and a lower differential pressure across the cement must be considered.

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