Achieving Long Term Well Integrity: An Engineered Solution for Production Casing in a Deepwater Environment

2014 ◽  
Author(s):  
V.. Reveth ◽  
R.. Giron Rojas ◽  
N.. Gupta ◽  
E.. Gonzaga
Keyword(s):  
Mechanical Performance ◽  
Rock Properties ◽  
Cement Matrix ◽  
Self Healing ◽  
Well Integrity ◽  
Zonal Isolation ◽  
Cement Sheath ◽  
The Impact ◽  
Fluid Pathway

Abstract In a deepwater environment, any remedial operation has a high impact on the overall costs during the life of the wells. The zonal isolation can be compromised due to the exposure of the well's main components (casing and cement) to the changes in the stress conditions. The changes in wellbore conditions can occur during the drilling, production, intervention, and decommissioning stages. Typically, conditions such as fluid pathway and high formation pressure are sufficient to lose zonal isolation. The fluid pathway can be a fissure, an induced crack in the cement sheath, a mud channel, a micro-microannulus, or changes in the cement matrix permeability. As a result of the oil industry technology developments, progresses, the advanced stress-modelling software and the availability of cement and rock properties property data have enabled to an improved understanding of the cement behavior under stress. Prevention of the loss of the hydraulic isolation provided by the primary cementing in the annulus can be assessed by predicting the mechanical failure of the cement sheath. Formation geo-mechanics is one of the main factors that help in designing a robust cement system for changing stresses. Furthermore, the consequence result of the cement sheath failure can be mitigated by the placement of placing a self-healing cement (SHC) system to maintain long-term zonal isolation. An interdisciplinary approach can be used to determine the following: Understand the impact of the well plan, and fluid densities on well integrity, in addition to cementing best practices.Characterize typical deepwater field formations, and establish limits for geo-mechanical values of each layer.Identify critical factors and focus on the pay zones.Understand potential issues and communication between the pay zones and the aquifers that are already previously confirmed.Determine risk of zonal communication assessment, mitigation, and prevention measurement implementations Once the formation data is validated by the operator, the life cycle of the well is simulated and the risk of zonal isolation can be evaluated. The results of this assessment can help the operator choose between to take the approach of mitigation, prevention, or a combination of both. The objective is to place a robust cement sheath with advanced mechanical performance in the pay zones that can resist the failures due to changing stresses during the well testing and production. This paper uses presents examples from a deepwater development field to show how cement systems with advanced mechanical properties counter the critical stresses during the lifecycle of a well and maintain zonal isolation.

Application of Resin-Cement Blend to Prevent Pressure Build-Up in Casing to Casing Annulus CCA: A Novel Approach to Improve Well Integrity

2021 ◽  
Author(s):  
Wajid Ali ◽  
Freddy Jose Mata ◽  
Ahmed Atef Hashmi ◽  
Abdullah Saleh Al-Yami
Keyword(s):  
High Pressure ◽  
Shear Bond Strength ◽  
Resin Cement ◽  
Cement Slurry ◽  
Well Integrity ◽  
Cement System ◽  
Zonal Isolation ◽  
Primary Cementing ◽  
Cement Sheath

Abstract Assurance of well integrity is critical and important throughout the entire well's life cycle. Pressure build-up between cemented casings annuli has been a major challenge all around the world. Cement is the main element that provides isolation and protection for the well. The cause for pressure build-up in most cases is a compromise of cement sheath integrity that allows fluids to migrate through micro-channels from the formation all the way to the surface. These problems prompt cementing technologists to explore new cementing solutions, to achieve reliable long-term zonal isolation in these extreme conditions by elevating shear bond strength along-with minimal shrinkage. The resin-cement system can be regarded as a novel technology to assure long term zonal isolation. This paper presents case histories to support the efficiency and reliability of the resin-cement system to avoid casing to casing annulus (CCA) pressure build-up. This paper presents lab testing and application of the resin-cement system, where potential high-pressure influx was expected across a water-bearing formation. The resin-cement system was designed to be placed as a tail slurry to provide a better set of mechanical properties in comparison to a conventional slurry. The combined mixture of resin and cement slurry provided all the necessary properties of the desired product. The slurry was batch-mixed to ensure the homogeneity of resin-cement slurry mixture. The cement treatment was performed as designed and met all zonal isolation objectives. Resin-cement’s increased compressive strength, ductility, and enhanced shear bond strength helped to provide a dependable barrier that would help prevent future sustained casing pressure (SCP). The producing performance of a well depends in great part on a good primary cementing job. The success of achieving zonal isolation, which is the main objective of cementing, is mainly attributed to the cement design. The resin-cement system is evolving as a new solution within the industry, replacing conventional cement in many crucial primary cementing applications. This paper highlights the necessary laboratory testing, field execution procedures, and treatment evaluation methods so that this technology can be a key resource for such operations in the future. The paper describes the process used to design the resin-cement system and how its application was significant to the success of the jobs. By keeping adequate strength and flexibility, this new cement system mitigates the risk of cement sheath failure throughout the life of well. It provides a long-term well integrity solution for any well exposed to a high-pressure environment.

Mud-Removal Efficiency Boost by Engineered Scrubbing Spacer in Cementing Operations at Caspian Sea

2021 ◽  
Author(s):  
Amanmammet Bugrayev ◽  
Ravindra Kumar Singh ◽  
Svetlana Nafikova ◽  
Ilshat Akhmetzianov ◽  
Guvanch Gurbanov ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Successful Implementation ◽  
Gas Migration ◽  
Negative Consequences ◽  
Well Integrity ◽  
Annular Gap ◽  
Challenging Environment ◽  
Zonal Isolation ◽  
Cement Sheath

Abstract Long-term well integrity and zonal isolation are the ultimate objectives for cementing in the well construction process. Effective mud removal plays an essential role in obtaining competent zonal isolation and hence should not be overlooked and underestimated. The negative consequences of poor mud removal can lead to microannulus, channeling, or gas migration, which might require costly time-consuming remediation. The conventional approach of optimizing spacers based on chemical interactions with the mud layer does not always yield desired results and, thus, demanding further improvement. In this paper we discuss the approach taken to boost the mud removal efficiency by implementing an innovative engineered scrubbing spacer containing fibers in a challenging environment, resulting in notable improvement in long-term cement sheath integrity. The engineered scrubbing fibers were thoroughly tested in the laboratory to ensure spacer stability and efficiency. The new spacer with an additional scrubbing capability was introduced to one of the major operators on the Caspian shelf and after successful implementation, it has now been used on more than 20 cementing operations. Scrubbing fibers concentration was optimized through thorough laboratory testing covering flowability, dispersibility, and mud removal efficiency; later, it was applied on most of the cement operations, including 4½-in. liners characterized by a very narrow annular gap across the hanger sections. Cement evaluation log results from those cementing operations demonstrated an improvement in mud removal efficiency, suggesting no issues associated with microannulus, channeling, or gas migration, thus confirming the effectiveness of the newly implemented engineered scrubbing spacer. The typical challenges associated with meeting the zonal isolation requirement on one of the offshore fields of the Caspian shelf, and the success of the approach taken to overcome those challenges by implementing the new engineered scrubbing spacer are discussed. The comparison of cement bond evaluation log results of the jobs where conventional spacer systems were used vs. those where the spacer with scrubbing capability was used are also presented, demonstrating the clear difference and improvement.

scholarly journals A REVIEW ON MECHANICAL PROPERTIES OF NATURAL FIBRE REINFORCED CONCRETE FOR RIGID PAVEMENTS

2021 ◽  
pp. 266-270
Author(s):  
M.Venkata Naga Prasad ◽  
Dr.J.Sridhar
Keyword(s):  
Low Cost ◽  
Natural Fibers ◽  
Natural Fibre ◽  
Cement Matrix ◽  
Rigid Pavements ◽  
Steel Bars ◽  
Coconut Coir ◽  
The Impact ◽  
Coconut Fibers

This study focuses on fiber reinforcement, specifically the use of jute and coir as a fiber reinforcing material in concrete. Natural fibers have been used to provide substantial toughness and strength in a very fragile cement matrix composite. It is necessary to make effective changes in this regard. Uses a very alkaline cement matrix to achieve durability. It is preferable to have a chemical composition that is clear. Reinforce the cement and change the surface of the fibers composite. The usage of jute fiber in this article is discussed. Concrete and the impact it has on the characteristics of the concrete it produces, for example this is an attempt to review the work that has just been completed. In the discipline, as well as to establish a foundation for future study in that case. It is critical to create low-cost building and reinforcing techniques that are suited for developing countries. If agricultural by-products like coconut coir can be used to replace steel bars as reinforcement, building costs can be reduced. Down significantly the purpose of this study is to evaluate the characteristics of coconut fibers. Species produced in India and their uses in many fields of engineering, notably civil engineering enhancing the long-term durability of concrete and mortar using engineering as a building material with the addition of coconut fibers the overall objective is to look into the possibility of utilizing domestic resources. Wastes for construction on a tiny scale a review of several researchers’ experiences utilizing is presented in this publication. The performance of coconut coir as a reinforcing component is explored in depth.

scholarly journals Numerical Modeling of Radial Fracturing of Cement Sheath Caused by Pressure Tests

2019 ◽  
Author(s):  
Sohrab Gheibi ◽  
Sigbjørn Sangesland ◽  
Torbjørn Vrålstad
Keyword(s):  
Numerical Code ◽  
Hydrocarbon Production ◽  
Well Integrity ◽  
Pressure Tests ◽  
Pressure Test ◽  
Zonal Isolation ◽  
Tensile Fractures ◽  
Fracture Opening ◽  
Cement Sheath ◽  
Geological Co2 Sequestration

Abstract To achieve an acceptable level of zonal isolation, well integrity should be guaranteed in hydrocarbon production and geological CO2 sequestration. Well pressure test can cause different types of failures in the well system leading to leakages through these failures. Laboratory evidences have revealed that occurrence of radial tensile fractures is likely during pressure tests. In this paper, we use a numerical code call MDEM which was formulated based on discrete element method. The code can model discontinuum feature of fractures. A model of a lab-sized pressure test was built and compared to an experiment previously published. The model was tested under different confinement levels and effect of the tensile strength of rock on the radial fracture was investigated at the same lab-scale. Fracture opening profiles are also presented showing the leakage potential of these fractures under different pressure level.

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.

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.

Boronic Ester-Polyurethane as a Self-Healing Coating Material for Offshore Top Side Structures Application

2021 ◽  
Author(s):  
Mohd Shamsul Farid Samsudin ◽  
Norfarah Diana Aba ◽  
Muzdalifah Zakaria ◽  
Azmi Mohammed Nor ◽  
Russell Varley ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Coating Layer ◽  
Salt Spray ◽  
The Self ◽  
Self Healing ◽  
Humidity Level ◽  
Healing System ◽  
Healing Efficiency ◽  
Harsh Conditions

Abstract Polymer coatings, especially epoxy and polyurethane paint systems, have been widely used to prevent corrosion of metallic components and structures. However, due to environmental and mechanical effects, the barrier efficiency of the coatings may be substantially compromised during transportation and service, as demonstrated by localized scratches, delamination, or stress-related microcracks. Application of a self-healing coating that can restore damages and recover its performance with minimal external intervention could prevent corrosion at the damaged coating. In this present work, the healing efficiency and long-term durability of Boronic Ester (BE) blended with Polyurethane (PU) as a self-healing system for top side coating of offshore platform structures was investigated. The BE was mixed at a ratio of 50:50 with PU resin and applied as a top layer on a PU coated steel plate with a thickness of approximately 300-350 μm. The healing efficiency, mechanical performance, and durability under simulated environmental conditions such as salt spray and UV were investigated according to the related ASTM standards. As a first step, the electrical impedance spectroscopy (EIS) and 3D profilemeter microscope were used to assess the healing ability of the scratched coating at room temperature and humidity level of 85 %. The mechanical performance of the self-healing coating layer was evaluated using a pull off adhesion test to investigate the compatibility of the self-healing system with the existing commercial PU topcoat system, while a long term 3000 hours salt spray and 4200 hours cyclic UV test were performed to evaluate the self-healing coating's durability in harsh conditions. Preliminary assessment using EIS and 3D profilemeter microscopes on the scratched PU/BE self-healing coating revealed significant healing efficiency of more than 80% for healing condition at ambient temperature and humidity level of 85%. The self-healing coating layer also demonstrated excellent adhesion efficiency, with adhesion greater than 300 psi suggesting good compatibility of the BE-PU layer with commercial PU coating. The salt spray and cyclic UV tests that were performed to determine the durability of the self-healing coating revealed that the 50BE/50PU layer remained intact and exhibited good healing performance with more than 80% efficiency even after exposure to harsh conditions. The findings from the study demonstrated that the BE/PU material has the potential to be used as a self-healing system for topside coating of offshore platforms structures, thereby lowering maintenance costs.

scholarly journals Detailed Analysis of the Influencing Parameters on the Self-Healing Behavior of Dynamic Urea-Crosslinked Poly(methacrylate)s

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3597 ◽  
Author(s):  
Abend ◽  
Zechel ◽  
Schubert ◽  
Hager
Keyword(s):  
Detailed Analysis ◽  
Mechanical Performance ◽  
Healing Process ◽  
Polymer Networks ◽  
Healing Time ◽  
The Self ◽  
Self Healing ◽  
Influencing Parameters ◽  
The Impact

For this paper, the self-healing ability of poly(methacrylate)s crosslinked via reversible urea bonds was studied in detail. In this context, the effects of healing time and temperature on the healing process were investigated. Furthermore, the impact of the size of the damage (i.e., area of the scratch) was monitored. Aging processes, counteracting the self-healing process, result in a decrease in the mechanical performance. This effect diminishes the healing ability. Consequently, the current study is a first approach towards a detailed analysis of self-healing polymers regarding the influencing parameters of the healing process, considering also possible aging processes for thermo-reversible polymer networks.

Sign in / Sign up

Export Citation Format

Share Document