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.

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.

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.

scholarly journals The influence of low amounts on in situ-polymerized bisphenol-diamine net in cement slurries prepared in seawater – structural analysis after long-term contact with in situ-generated mud-acid fracturing fluid

2020 ◽  
Vol 25 (1) ◽  
Author(s):  
Danilo Oliveira Santos ◽  
Ivory Marcos Gomes dos Santos ◽  
Joenesson Filip Santos Ribeiro ◽  
Eunice Fragoso Silva Vieira ◽  
Gwenn Le Saoût ◽  
...  
Keyword(s):  
Oil Well ◽  
Cement Slurry ◽  
27Al Nmr ◽  
Chemical Structures ◽  
Zonal Isolation ◽  
Order Variable ◽  
Adsorption Desorption ◽  
Kinetic Features

ABSTRACT Inadequate zonal isolation in oil wells can provoke safety and environmental problems. New cement slurries can avoid such problems. In this work, novel cement slurries were prepared in the presence of seawater with in situ-formed epoxy resin–ethylenediamine. The new slurries were tested in relation to their mechanical properties and characterized by FTIR, XRD, TG/DTG, porosimetry by N2 adsorption-desorption and solid-state 29Si and 27Al NMR. Some kinetic features of long-term contact of the slurries with in situ-generated mud-acid were performed to evaluate the performances of the new slurries in routine acidizing procedures in oil well industry. The experimental kinetic data were well fitted to order-variable exponential kinetic model and a factorial design of four variables (24). In these studies, it was possible to evaluate in detail how some important experimental factors act on the quantities of acid that interact with the pastes, as well as to verify how these factors affect the speed with which the mud-acid interacts with the slurries. The results strongly suggest that the interactions occurred at epoxy/ethylenediamine cement slurry/mud-acid interfaces are due to surface reactions with preservation of the chemical structures of the cement slurries, even after long-term contact with mud-acid. The new cement slurry present good features to be used in environmental-friendly procedures in oil well field.

Innovative and Unconventional Approach to Cementing A Ballooning Well Leading to Good Zonal Isolation

2021 ◽  
Author(s):  
Lingges Devadass ◽  
Avinash Kishore Kumar ◽  
Chee Hen Lau ◽  
Myat Thuzar ◽  
Tiyor Sion Ban ◽  
...  
Keyword(s):  
Static Condition ◽  
Job Design ◽  
Back Pressure ◽  
Great Success ◽  
Cementing Technique ◽  
Cement Slurry ◽  
Fracture Pressure ◽  
Production Wells ◽  
Zonal Isolation ◽  
Actual Operation

Abstract Good cement bond log and sufficient zonal isolation are important aspects of production wells. Proper cement design and displacement are essential to ensure the cement objectives are met. Well A is one of four development wells, located in East Malaysia. The well was a gas producer, therefore good zonal isolation at the gas intervals are of paramount importance. Coupled with high inclination and formation with narrow pore pressure and fracture pressure margin, ballooning condition was encountered while drilling the reservoir section. These challenging conditions push the boundary of conventional cementing design further to implementation of unique and novel cementing approach to ensure no losses, minimal mud contamination with cement slurry and ultimately produce good zonal isolation. This unexpected conditions of the well lead to re-designing the cement slurry and revamping the placement procedure for the 7" liner across production zone. Operator’s limited experience with cementing in ballooning conditions hampered any reference which could be useful for the job design. Required formation permeability, porosity data, mud flowback volume and duration of mud flowback at static condition were carefully assessed and taken into consideration in the cementing job design and pumping program. Based on the data gathered, an unconventional cement placement technique with specialized spacer and slurry design were proposed Well A, instead of complex back-pressure application technique in order to meet all required cementing objectives. The cementing job was executed as per plan and no losses were observed during the entire cement job. Cement evaluation through cement bond logs indicated that enough isolations across the hydrocarbons zones of interest were obtained. Moreover, cement bond logs also showed good zonal isolation were also attained above and below perforation intervals showing very little contamination of mud backflow into the cement slurry. The cementing technique used proved to be relatively simpler and cheaper as it requires no additional equipment to rig up to execute compared to complex back-pressure technique which done incorrectly may lead to losses or remedial cementing. The successful cementing operation showcased that the planned cementing technique and slurry design were effective for the cementing of abnormal well conditions. This success also highlighted the importance of job pre-planning and necessity to acquire all required data prior to actual operation. The job technique and design was replicated in subsequent wells which had similar well ballooning condition and resulted in great success.

High Performance Tailored Mechanically Enhanced Cement Slurry Helped in Delivering Dependable Barriers Across HPHT Reservoir: Case Study from UAE Offshore

2021 ◽  
Author(s):  
Patrick Manga ◽  
Sherif Mohamed ◽  
Devesh Bhaisora
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Cement Slurry ◽  
Hydrocarbon Production ◽  
Well Production ◽  
High Pressure High Temperature ◽  
Zonal Isolation ◽  
Long Lifetime ◽  
Environment Stress

Abstract The concept of zonal isolation has evolved recently addressing new industry challenges to provide dependable barriers throughout the life of the well. This helps ensure long term well integrity for safer and more efficient hydrocarbon production, especially for the fields predicted to have a long lifetime. This leads to tailoring of cement slurry designs for superior mechanical parameters to avoid deteriorating them under post cementing operational loads. Following cementing best practices is a key parameter to achieve a successful cementing job, however adequate mechanical properties will help a cement slurry to withstand all the cyclic loads that the well will experience during its lifetime. Determining these properties and tailoring cement slurry designs to meet these properties will help ensure that the cement slurry will still survive these loads, all the way from placement until it has experienced all the post cementing operational loads including but not limited to multiple pressure testing, unloading the well, perforations, various thermal loads during well production, hydraulic fracturing etc. The tailored cement slurry was able to provide an adequate solution of such challenges faced by an operator in Offshore UAE under a high pressure – high temperature (HPHT) environment. Stress modelling was performed for the life of the well considering post cementing operations. This helped in determining optimum mechanical properties required for the cement slurries considered. Specialized testing was performed in both lab and yard to achieve such properties for field execution. Based on various stress and hydraulic modelling, slurries ranging from 13 to 17.5 ppg were designed and pumped successfully in the wellbore. Post cementing bond logs showed adequate placement of a tailored dependable barrier across a complete wellbore including an HPHT reservoir section. This approach can be used for wells with similar challenges around the world for long term zonal isolation.

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.

Long-Term Survival of a Flat-on-Flat Total Condylar Knee Arthroplasty Fixed with a Hybrid Cementing Technique for Tibial Components

2012 ◽  
Vol 22 (4) ◽  
pp. 305-312 ◽  
Author(s):  
Christian Carulli ◽  
Fabrizio Matassi ◽  
Lorenzo Nistri ◽  
Roberto Civinini ◽  
Massimo Innocenti
Keyword(s):  
Knee Arthroplasty ◽  
Cementing Technique ◽  
Term Survival ◽  
Long Term Survival

scholarly journals Gene Therapy in Hemophilia: Recent Advances

2021 ◽  
Vol 22 (14) ◽  
pp. 7647
Author(s):  
E. Carlos Rodríguez-Merchán ◽  
Juan Andres De Pablo-Moreno ◽  
Antonio Liras
Keyword(s):  
Gene Therapy ◽  
Adverse Events ◽  
Factor Viii ◽  
Coagulation Factor ◽  
Cost Savings ◽  
Factor Ix ◽  
Clotting Factors ◽  
Advanced Therapies ◽  
Potential Benefits

Hemophilia is a monogenic mutational disease affecting coagulation factor VIII or factor IX genes. The palliative treatment of choice is based on the use of safe and effective recombinant clotting factors. Advanced therapies will be curative, ensuring stable and durable concentrations of the defective circulating factor. Results have so far been encouraging in terms of levels and times of expression using mainly adeno-associated vectors. However, these therapies are associated with immunogenicity and hepatotoxicity. Optimizing the vector serotypes and the transgene (variants) will boost clotting efficacy, thus increasing the viability of these protocols. It is essential that both physicians and patients be informed about the potential benefits and risks of the new therapies, and a register of gene therapy patients be kept with information of the efficacy and long-term adverse events associated with the treatments administered. In the context of hemophilia, gene therapy may result in (particularly indirect) cost savings and in a more equitable allocation of treatments. In the case of hemophilia A, further research is needed into how to effectively package the large factor VIII gene into the vector; and in the case of hemophilia B, the priority should be to optimize both the vector serotype, reducing its immunogenicity and hepatotoxicity, and the transgene, boosting its clotting efficacy so as to minimize the amount of vector administered and decrease the incidence of adverse events without compromising the efficacy of the protein expressed.

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