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.

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.

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.

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.

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.

Foamed Cement Analysis With Computed Tomography

2014 ◽  
Author(s):  
Dustin Crandall ◽  
Magdalena Gill ◽  
Johnathan Moore ◽  
Barbara Kutchko
Keyword(s):  
Computed Tomography ◽  
High Stress ◽  
Three Dimensional ◽  
Image Data ◽  
Gas Migration ◽  
Structure Quality ◽  
Air Voids ◽  
Well Integrity ◽  
X Ray Computed

Foamed cements are widely used for cementing oil or gas wells that require lightweight slurries, gas migration prevention, or wells in high-stress environments. When this manufactured slurry solidifies in the sub-surface environment the distribution of gas voids can affect the resultant strength, permeability, and stability of the wellbore casing. Researchers at the National Energy Technology Laboratory have produced the first high-resolution X-ray computed tomography (CT) three-dimensional images of atmospheric and field generated foamed cement across a range of foam qualities. CT imaging enabled the assessment and quantification of the foamed cement structure, quality, and bubble size distribution in order to provide a better understanding of this cement. Ultimately, this research will provide industry the knowledge to ensure long-term well integrity and safe operation of wells in which foamed cements are used. Initial results show that a systematic technique for isolating air voids can give consistent results from the image data, laboratory generated foamed cements tend to be uniform, and that high-gas fraction foamed cements have large interconnected void spaces.

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.

scholarly journals Possibilities of Limiting Migration of Natural Gas in Boreholes in the Context of Laboratory Studies

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4251
Author(s):  
Marcin Kremieniewski ◽  
Rafał Wiśniowski ◽  
Stanisław Stryczek ◽  
Grzegorz Orłowicz
Keyword(s):  
Structural Strength ◽  
Oil Industry ◽  
Hardened Cement ◽  
Gas Migration ◽  
Technological Parameters ◽  
Cement Slurry ◽  
Cement Sheath ◽  
Selection Of

Gas migration through fresh and hardened cement slurry is an ongoing problem in the oil industry. In order to eliminate this unfavourable phenomenon, research is being conducted on new compositions of slurries for gas wells. The article presents the results of research for slurries with low and high resistance to gas migration. The proper selection of the quantity and quality of components makes it possible to design slurry with the required static structural strength values. In addition, the cement sheath of such anti-migration slurry has low porosity and a very low proportion of large pore spaces. Additionally, the mechanical parameters do not decrease during long-term deposition in borehole-like conditions. By obtaining these results, it was possible to design slurry whose cement sheath has high corrosion resistance. The new slurry has a lower water-cement ratio. Additionally, GS anti-migration copolymer, anti-filter additive and latex are used. The presence of n-SiO2 aqueous solution and microcement allows for sealing the microstructure of the hardened cement slurry. Such modifications significantly improve the technological parameters of the cement slurry and the cement coat formed from it.

Cementless Well Construction Opens the Full Control on Well Integrity for the Life of the Well

2021 ◽  
Author(s):  
Catalin Teodoriu ◽  
Opeyemi Bello ◽  
R. R. Vasquez ◽  
Ryan M. Melander ◽  
Yosafat Esquitin
Keyword(s):  
Element Analysis ◽  
New Era ◽  
Track Record ◽  
Novel Technology ◽  
Well Integrity ◽  
Load Carrying ◽  
Cement Sheath ◽  
Cement Manufacturing ◽  
Previous Paragraph

Abstract Well construction has relied on two main elements, casing and cement, to achieve the well goals while maintaining the highest possible well integrity. Can cementless well construction achieve similar goals? This paper is investigating the various well construction concepts proposed over the years and will analyze the cement's ability to withstand long term well loads. First, a review of various well construction concepts such as slimhole, conventional, pre-salt and horizontal wells. We will normalize the casing to cement thickness ratio by validating and proposing a simple mathematical calculation for establishing this ratio. Our calculations have shown that in the case of slimhole well concept, the thin cement sheath cannot serve as a strong well barrier as defined by current standards, and thus a new solution might be necessary. The second part will look at current new trends in wellbore construction that include external casing packers and other solutions such as metallic wellbore isolation solutions. Hydraulically expanded metal packers are a robust and reliable alternative to cement. They are each mounted to a casing joint and can be rotated while running in hole. They have a proven deployment track record of high diametrical expansion, conforming to the wellbore geometry, while isolating differential pressures more than 15,000psi. Exploration of load carrying capabilities will be completed using Finite Element Analysis (FEA), simulating the different well scenarios as described in the previous paragraph. This will enable us to establish which well types can use this novel technology for the replacement of cement. The paper will conclude with one possible solution that could be used to mitigate cement problems by shifting the well construction concept to a cementless new era. Also, understanding that the cement manufacturing process is highly CO2 intensive, emissions per well could be reduced through the newly proposed concept.

scholarly journals Cement sheath modification using nanomaterials for long-term zonal isolation of oil wells: Review

2017 ◽  
Vol 156 ◽  
pp. 662-672 ◽  
Author(s):  
Narjes Jafariesfad ◽  
Mette Rica Geiker ◽  
Yi Gong ◽  
Pål Skalle ◽  
Zhiliang Zhang ◽  
...  
Keyword(s):  
Oil Wells ◽  
Zonal Isolation ◽  
Cement Sheath
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