Assurance of Long-Term Well Integrity in Highly Corrosive Downhole Environment

2021 ◽  
Author(s):  
Mohammad Arif Khattak ◽  
Agung Arya Afrianto ◽  
Bipin Jain ◽  
Sami Rashdi ◽  
Wahshi Khalifa ◽  
...  
Keyword(s):  
Gas Production ◽  
Simulation Software ◽  
Successful Implementation ◽  
Horizontal Section ◽  
Well Integrity ◽  
Well Design ◽  
Cement System ◽  
Zonal Isolation ◽  
Fit For Purpose

Abstract Portland cement is the most common cement used in oil and gas wells. However, when exposed to acid gases such as carbon dioxide (CO2) and hydrogen sulfide (H2S) under downhole wet conditions, it tends to degrade over a period of time. This paper describes the use of a proprietary novel CO2 and H2S resistant cement system to prevent degradation and provide assurance of long-term wellbore integrity. The CO2-resistant cement was selected for use in one of the fields in Sultanate of Oman after a well reported over 7% CO2 gas production resulting in well integrity failure using conventional cements. The challenge intensified when the well design was modified by combining last two sections into one long horizontal section extending up to 1,600 m. The new proposed cement system was successfully laboratory- tested in a vigorous CO2 environment for an extended period under bottomhole conditions. Besides selecting the appropriate chemistry, proper placement supported by advanced cement job simulation software is critical for achieving long-term zonal isolation. The well design called for a slim hole with 1,600 m of 4 ½-in liner in a 6-in horizontal section where equivalent circulating density (ECD) management was a major challenge. An advanced simulation software was used to optimize volumes, rheologies, pumping rates, and ECDs to achieve the desired top of cement. The study also considered a detailed torque and drag analysis in the horizontal section, and fit- for-purpose rotating-type centralizers were used to help achieve proper cement coverage. To date, this cement system has been pumped in 32 wells, including 24 with 6-in slimhole horizontal sections with no reported failures. The paper emphasizes the qualification and successful implementation of fit-for-purpose design of CO2- and H2S-resistant cement as well as optimized execution and placement procedures to achieve long-term zonal isolation and well integrity in a complex slimhole horizontal well design.

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.

A Client's Fit for Purpose Solutions in Well Abandonment

2021 ◽  
Author(s):  
Yun Thiam Yap ◽  
Avinash Kishore Kumar
Keyword(s):  
Cost Effective ◽  
Well Design ◽  
Industry Standards ◽  
Cost Effective Approach ◽  
Reservoir Conditions ◽  
Standards And Regulations ◽  
Fit For Purpose ◽  
Well Abandonment ◽  
Oil Company

Abstract Typically, most of the well abandonment practice is reference to the recognized industry standards i.e. NORSOK, UK Oil & Gas and etc, and this is how the wells abandonment was carried out in the past. These practices however evolved/changed over time with lessons learnt and experiences and turn into a fit for purpose solutions for the Client. The shift in international and local standards and regulations for a robust plug and abandonment approach has placed the need for a better and long lasting permanent P&A methodology. Adhering to the existing industry standards in well abandonment is somehow not practical and not cost effective to be implemented in different part of the well, where there are major differences in local regulations, reservoir conditions, caprock thickness, well design philosophy and etc. The magnitude of abandonment cost increase is not at par with the risk reduction in long term hydrocarbon leakage. A fit for purpose solutions is recommended in closing the gap between cost and risk. Due to the extremely varied well architecture between wells, the approach to permanent abandonment varies depending on casing sizes, presence of packers and no of casings present to the caprock area. On top of that, identifying the highest depth for a placement of cement plug will reduce on the amount of plugs to be placed, saving rig time and operational time. So far, 16 idle wells have since been permanently abandoned with the systematic approach of applying caprock restoration concept and reinstating the poor isolation across caprock areas with cement with the assistance of technology to the likes of perf-wash-cement, and hydro mechanical casing cutter. These wells have successfully been abandoned as per host authority standards. This paper will explore a major local oil company’ approach to decommissioning of wells, in line with local regulations enforced, while ensuring a cost effective approach is applied in line with the available technologies.

Nanosized Magnesium Oxide With Engineered Expansive Property for Enhanced Cement-System Performance

SPE Journal ◽  
2017 ◽  
Vol 22 (05) ◽  
pp. 1681-1689 ◽  
Author(s):  
Narjes Jafariesfad ◽  
Mette Rica Geiker ◽  
Pål Skalle
Keyword(s):  
Heat Treatment ◽  
Young’S Modulus ◽  
Magnesium Oxide ◽  
Young's Modulus ◽  
Oil Well ◽  
Cement Slurry ◽  
Expansive Agent ◽  
Cement System ◽  
Zonal Isolation

Summary The bulk shrinkage of cement sheaths in oil wells can result in loss of long-term zonal isolation. Expansive additives are used to mitigate bulk shrinkage. To compensate effectively for bulk shrinkage during the late plastic phase and the hardening phase of the cement system, the performance of the expansive additive needs to be regulated considering the actual cement system and placement conditions. This paper presents an introductory investigation on the potential engineering of nanosized magnesium oxide (MgO) (NM) through heat treatment for use as an expansive agent in oilwell-cement systems. In this study, the bulk shrinkage of a cement system was mitigated by introducing NM with designed reactivity to the fresh cement slurry. The reactivity of NM was controlled by heat treatment. A dilatometer with corrugated molds was used to measure the linear strain of samples cured at 40°C and atmospheric pressure. The effect of NMs differing in reactivity on tensile properties of cement systems cured for 3 days at 40°C was examined by use of the flattened Brazilian test. The reactivity of the NM played a key role in controlling the bulk shrinkage of the cement system. Addition of only 2% NM by weight of cement (BWOC) with appropriate reactivity was sufficient to maintain expansion of the cement system. Adding NM to the cement system also resulted in improved mechanical flexibility. The NM with highest reactivity caused the largest reduction in Young's modulus at 3 days and, in general, the ratio of tensile strength to Young's modulus improved through the addition of NM to the cement system. Our work demonstrates that controlling the reactivity of the additive is a promising method to mitigate bulk shrinkage of cement systems and thereby to sustain the mechanical properties of the cement sheath in the oil well at an acceptable level.

Evaluation of Specialized Cement System for Long-Term Steam Injection Well Integrity

2010 ◽  
Author(s):  
Elena M. Pershikova ◽  
Alice Chougnet ◽  
Anthony Loiseau ◽  
Walid Khater ◽  
Andre Garnier
Keyword(s):  
Steam Injection ◽  
Injection Well ◽  
Well Integrity ◽  
Cement System

Surface Casing Cum Production Casing Well Design – Extreme but Techno-economically Acceptable Approach

2021 ◽  
Author(s):  
M Hatta M Yusof ◽  
Rahimah A Halim ◽  
Nurfaridah Ahmad Fauzi ◽  
Ahgheelan Sella Thurai ◽  
M Zulfarid Khalid ◽  
...  
Keyword(s):  
Low Cost ◽  
Oil Price ◽  
Significant Component ◽  
Field Development ◽  
Well Integrity ◽  
Well Design ◽  
Open Hole ◽  
Well Trajectory ◽  
Fit For Purpose

Abstract 2020 marks another challenging year for O&G sector, with the operators being in an uphill battle to survive the plunging oil price. With CAPEX rationalization underway, future field development may only be prospective via implementation of low-cost Field Development Plan (FDP). As well cost is a significant component of development CAPEX, low well cost must be pursued, by designing fit-for-purpose wells. For relatively shallow (≈2000 m-MD in meterage drilled) wells, a simple well design consisting of only two-hole sections (excluding Conductor) shall be considered. This design approach though, may require the Surface Casing to also be the Production Casing (if only Production Liner will be ran in the production hole section or if open hole completion is feasible or if cemented monobore completion strategy is adopted). This aspect of casing design (having Surface cum Production Casing) does indeed pose well integrity concerns as the quality of cement behind the Surface cum Production Casing is uncompromisable to ensure no gas can breach to surface. This paper discusses the design measures than can be incorporated into the well trajectory, cementing plan, and production surveillance in order to support the feasibility of Surface cum Production Casing concept.

Self Sealing Cement System Enables Prevention of Water Intrusion and Long Term Zonal Isolation in Um Gudair Field: A Case Study in West Kuwait

2020 ◽  
Author(s):  
Ali Hussain Jaffar ◽  
Jassem Ali Mohammed ◽  
Mohammed Khaja ◽  
Hassan Haddad ◽  
Sushil Raturi ◽  
...  
Keyword(s):  
Water Intrusion ◽  
Cement System ◽  
Zonal Isolation

Breakthrough Cementing Technology for Enhanced Well Integrity in Myanmar Offshore Shallow Gas Well

2021 ◽  
Author(s):  
Yi Li ◽  
Mohammad Solim Ullah ◽  
Wu Chang Ai ◽  
Thirayu Khumtong ◽  
Kantaphon Temaismithi ◽  
...  
Keyword(s):  
Gas Migration ◽  
Negative Effects ◽  
Shallow Gas ◽  
Gas Well ◽  
Lost Circulation ◽  
Security Issues ◽  
Zonal Isolation ◽  
Primary Cementing ◽  
Fit For Purpose

Abstract In Myanmar offshore, a substantially promising gas reservoir was discovered, the objective of primary cementing is to achieve long term zonal isolation, as any gas migration to surface would cause production loss, as well as significant security issues. Remedial cementing work will cause costly non production time, while the result will be compromised. Shallow gas migration, lost circulation and mud removal, all these factors cause undesired negative effects for cementing design, While the objective is to provide a firm barrier and good zonal isolation, this paper will describe in details the cementing challenge, the methodology, and how the slurry parameter was designed and evaluated for a Fit-For-Purpose solution.

Application of Key Technique in Splitter Wellhead Cementing Enabled Successful and Safe Operations

2021 ◽  
Author(s):  
Chee Hen Lau ◽  
Avinash Kishore Kumar ◽  
Myat Thuzar
Keyword(s):  
Cost Savings ◽  
Pressure Profile ◽  
Construction Technology ◽  
Cementing Technique ◽  
Cement Slurry ◽  
Planning Phase ◽  
Well Design ◽  
Zonal Isolation ◽  
Unique Approach

Abstract This paper describes the application of key technique for splitter wellhead cementing of top-hole section in conductor-sharing wells in dozens of development wells in offshore Malaysia. Its objective is to elaborate on the challenges faced during the well planning phase, methodology of cementing technique, cementing slurry design as well as solutions outcome and lessons learnt. Limitations of current software in the industry to simulate the conductor-sharing well cementation and approaches to maneuver through these limitations are also discussed. During the well planning phase, cementing technique to address the risks associated with splitter wellhead cementing such as accidental cementation of dummy string, poor cement coverage in shared conductor, and losses uncertainties were analyzed. The cementing execution results of first batch of wells are examined, i.e. pressure profile, cement returns as well as opportunities for improvement were documented and translated into recommendations leading to eventual success for future well design. The cement slurry design for each casing in the splitter wellhead are also established based on its associated job objectives which is based on the unique approach in splitter wellhead cementing. The establishment of key cementing technique for such an unconventional well construction technology is important in order to ensure continuous success both in cement placement as well as cement slurry design. The best practices are currently being replicated by other major operators in Malaysia for all splitter wellhead cement design. The learnings from the technique are incorporated into the technical standard of Malaysia operator as well to serve as a specific mandated requirement for future operations. An integrated study of wellhead design, drilling practices and cementing technologies enabled a novel methodology to assure long term zonal isolation for the wells and innovation in the cementing approach enable cost savings for the operator as the wells can be drilled in a safe, efficient and cheaper way.

Ensuring Well Integrity in Deepwater using a fit for Purpose Advanced Cement System

2011 ◽  
Author(s):  
Salim Taoutaou ◽  
Cinto Azwar ◽  
Rakesh Pathak ◽  
Degaul Nzoutchoua Nana ◽  
Prakash Anand Ajwani
Keyword(s):  
Well Integrity ◽  
Cement System ◽  
Fit For Purpose
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