Review: Role of chemistry, mechanics, and transport on well integrity in CO2 storage environments

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.

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Role of salt dissolution processes in the long-term performance assessment of CO2 storage in the Weyburn field

Greenhouse Gas Control Technologies 7 ◽

10.1016/b978-008044704-9/50290-1 ◽

2005 ◽

pp. 2147-2151

Author(s):

J JIMENEZ ◽

R CHALATURNYK ◽

L KREIS

Keyword(s):

Performance Assessment ◽

Co2 Storage ◽

Salt Dissolution ◽

Weyburn Field ◽

Long Term Performance ◽

Term Performance

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Subsea Re-Abandonment Strategies for High-Risk Wells to Minimize Leakage Risk in a Depleted Field for CO2 Storage

10.2118/207944-ms ◽

2021 ◽

Author(s):

Parimal A Patil ◽

Debasis P. Das ◽

Pankaj K. Tiwari ◽

Prasanna Chidambaram ◽

Renato J. Leite ◽

...

Keyword(s):

High Risk ◽

Co2 Storage ◽

Horizontal Stress ◽

Leakage Rate ◽

Storage Site ◽

Co2 Leakage ◽

Well Integrity ◽

Abandoned Wells ◽

Fracture Gradient ◽

Maximum Horizontal Stress

Abstract CO2 storage in a depleted field comes with the risk that is associated with wells integrity which is often defined as the ability to contain fluids with minimum to nil leakage throughout the project lifecycle. The targeted CO2 storage reservoir in offshore Malaysia has existing abandoned exploration/appraisal, and development wells. With a view of developing such CO2 storage sites, it is vital to maintain the integrity of the abandoned wells. High-risk characterized wells need to be analyzed and remedial action plan to be defined by understanding the complexity involved in restoring the integrity. This will safeguard CO2 containment for decades. Abandoned exploration/appraisal wells in the identified field are >40 years old and were not designed to withstand CO2 corrosion environment. Downhole temperature and pressure conditions may have further degraded the wellbore material strength elevating corrosion susceptibility. The reservoir simulation predicts that the CO2 plume will reach to these abandoned wells during the initial phase of total injection period. Single well was selected to assess the loss of containment through the composite structure along the wellbore and to determine the complexity in resorting the well integrity. CO2 leakage rates through all possible pathways were estimated based on numerical models and the well is characterized for its risk. For unacceptable leakage risk, the abandoned well needs to be re-entered to restore the performance of barriers. Minimum plug setting depth (MPSD) and caprock restoration considers original reservoir pressure(3450psia) anticipating the pressure buildup upon CO2 injection and is derived based on fracture gradient and maximum horizontal stress. This paper elaborates unique challenges associated with locating abandoned wells that are submerged below seabed. Top and side re-entry strategies are discussed to overcome challenges. Based on past abandonment scheme, leakage rate modeling calculates estimated leakage rate of ~460SCFD at higher differential pressure of around 3036psia at shallowest barrier and ~15SCFD for differential pressure of 1518psia at deepest barrier. Sensitivity analysis has been carried out for critical barrier parameters (cement permeability, cracks, fractures) to the containment ability and improving understanding of quality of barriers, uncertainties, and complexities for CO2 leakage risk. The paper proposes two(2) minimum plug setting depths (3550ft & 3750ft) derived based on fracture gradient and maximum horizontal stress. Perforate-wash-cement (PWC) and section milling were compared for operational efficiencies to achieve caprock restoration. for MPSD out strategic options to restore well integrity by remediating casing/cement barriers at by performing best fit abandonment technique to contain CO2 in the reservoir. Well integrity risk is assessed for existing plugged and abandoned (P&A) wells in a carbon storage site. Optimized remedial actions are proposed. Quantification of all the uncertainties are resolved that may affect long-term security of CO2 storage site.

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Monitoring well integrity at the Cranfield field phase III CO2 storage project

International Journal of Greenhouse Gas Control ◽

10.1016/j.ijggc.2021.103341 ◽

2021 ◽

Vol 109 ◽

pp. 103341

Author(s):

Andrew Duguid ◽

Boyun Guo ◽

Runar Nygaard ◽

TS Ramakrishnan ◽

Nikita Chugunov

Keyword(s):

Co2 Storage ◽

Phase Iii ◽

Field Phase ◽

Monitoring Well ◽

Well Integrity

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

10.2523/iptc-21472-ms ◽

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.

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Injection and Reservoir Hazard Management: The Role of Injection-Induced Mechanical Deformation and Geochemical Alteration at In Salah CO2 Storage Project: Status ReportQuarter end, June 2009

10.2172/964517 ◽

2009 ◽

Cited By ~ 2

Author(s):

J P Morris ◽

W W McNab ◽

S K Carroll ◽

Y Hao ◽

W Foxall ◽

...

Keyword(s):

Co2 Storage ◽

Mechanical Deformation ◽

Hazard Management

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How Heuristics and Biases Impact Judgment and Decision Making in Well Integrity Operations

Volume 8: Polar and Arctic Sciences and Technology; Petroleum Technology ◽

10.1115/omae2019-96820 ◽

2019 ◽

Author(s):

Catalin Teodoriu ◽

Saeed Salehi

Keyword(s):

Decision Making ◽

Human Factor ◽

Oil And Gas ◽

Cognitive Biases ◽

Critical Role ◽

Organizational Factors ◽

Judgment And Decision Making ◽

Well Control ◽

Well Integrity

Abstract The contribution of the human factor in major oil and gas accident events is fully-fledged and admitted. The root cause analysis and incident investigation of these accidents reveal that many of them could have been prevented, with the perception that there was a cascade of failures in human factor elements. This is easy to comprehend, as the human factor has not been accentuated thoroughly in this industry and traditionally the focus has been on personnel knowledge and competence. A previous paper presented at OMAE 2018 had a brief overview of well integrity, and the pivotal role of cementing operations in well control. The critical role of human and organizational factors in cementing operations and well control was addressed. Furthermore, an outline of the newly implemented SEMS II regulations was also offered, with insight into adjustments that could enhance this program’s modest requirements. In this paper, the goal is to examine the key heuristics that operational people employ in well integrity procedures. Some of these cognitive biases include status-quo and confirmation biases. Several examples will be discussed to show how underlying biases can lead to improper decisions. Unfortunately, some of these biases have been embedded in companies cultures for several decades now, and are hard to change overnight. Some of these can often lead to tremendous operational costs and not necessary solving the problem. It is highly recommended that training schools consider the problems of psychological biases and start implementing case studies for improvement in judgment and decision making.

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