Experimental Investigations on the Effect of Mixing Procedures on the Rheological Properties of Oilwell Cement Slurries

2021 ◽  
pp. 1-12
Author(s):  
Fatemeh K. Saleh ◽  
Catalin Teodoriu

Abstract Well cementing is an essential operation in the oil and gas industry, and it is a key material to ensure wellbore integrity through the life of the well. Improper cement design can trigger well construction risks such as de-bonding and leakage pathways near-wellbore and through the annulus. Mixing non-newtonian fluids is one of the most challenging tasks, especially for pseudoplastic fluids exhibiting yield stress, such as wellbore cement slurry. Mixing conditions for cement slurries and their effect on rheological properties and thickening time has been debated through the literature. In this study, based on laboratory-scale experiments, we provide testing results for rheological properties and thickening time by changing mixing conditions. Our results show that slurries mixed under similar mixing energy do not necessarily result in similar rheological properties. Comparing rheological measurements from lower mixing energy to higher mixing energy, plastic viscosity decreases; however, yield point increases. This implies the dual opposite effect of mixing time on rheological properties. This may have severe implications for field operations where mixing must be improved to enable successful cement operation.

2021 ◽  
Author(s):  
Emmanuel Ayodele ◽  
David Ekuma ◽  
Ikechukwu Okafor ◽  
Innocent Nweze

Abstract Drilling fluid are complex fluids consisting of several additives. These additives are added to enhance and control the rheological properties (such as viscosity, gel strength and yield point) of the mud. These properties are controlled for effective drilling of a well. This research work is focused on determining the rheological behavior of drilling mud using industry-based polymer and Irvingia Gabonensis (ogbono) as viscosifiers. Water based muds were formulated from the aforementioned locally sourced viscosifier and that of the conventional used viscosifier (Carboxylmetyl cellulose, CMC). Laboratory tests were carried out on the different muds formulated and their rheological properties (such as yield stress, shear stress, plastic viscosity and shear rate) are evaluated. The concentration of the viscosifiers were varied. The expected outcome of the research work aims at lowering the total drilling cost by reducing the importation of foreign polymer which promotes the development of local content in the oil and gas industry. The research compares the rheology of mud samples and the effect of varying the concentration (2g, 4g, 6g, 8g, and 10g) of both CMC and Ogbono and determining the changes in their rheological properties. The total volume of each mud sample is equivalent to 350ml which represent one barrel (42gal) in the lab. From the result, at concentration of 2g, the ogbono mud has a better rheology than the CMC mud, but at a concentration above 2g, CMC mud shows a better rheology than ogbono mud, that is, as the concentration of CMC is increased, the rheological properties of the mud increased while as the concentration of ogbono is increased the rheological properties decreased. The viscosity of the drilling fluid produced from the ogbono were lower than that of CMC, it could be used together with another local product such as cassava starch, offor or to further improve the rheology and then be a substitute to the conventional viscosifiers.


Author(s):  
George Kwatia ◽  
Mustafa Al Ramadan ◽  
Saeed Salehi ◽  
Catalin Teodoriu

Abstract Cementing operations in deepwater exhibit many challenges worldwide due to shallow flows. Cement sheath integrity and durability play key roles in the oil and gas industry, particularly during drilling and completion stages. Cement sealability serves in maintaining the well integrity by preventing fluid migration to surface and adjacent formations. Failure of cement to seal the annulus can lead to serious dilemmas that may result in loss of well integrity. Gas migration through cemented annulus has been a major issue in the oil and gas industry for decades. Anti-gas migration additives are usually mixed with the cement slurry to combat and prevent gas migration. In fact, these additives enhance and improve the cement sealability, bonding, and serve in preventing microannuli evolution. Cement sealability can be assessed and evaluated by their ability to seal and prevent any leakage through and around the cemented annulus. Few laboratory studies have been conducted to evaluate the sealability of oil well cement. In this study, a setup was built to simulate the gas migration through and around the cement. A series of experiments were conducted on these setups to examine the cement sealability of neat Class H cement and also to evaluate the effect of anti-gas migration additives on the cement sealability. Different additives were used in this setup such as microsilica, fly ash, nanomaterials and latex. Experiments conducted in this work revealed that the cement (without anti-gas migration additive) lack the ability to seal the annulus. Cement slurries prepared with latex improved the cement sealability and mitigated gas migration for a longer time compared to the other slurries. The cement slurry formulated with a commercial additive completely prevented gas migration and proved to be a gas tight. Also, it was found that slurries with short gas transit times have a decent potential to mitigate gas migration, and this depends on the additives used to prepare the cement slurry.


2021 ◽  
Author(s):  
Nachiket Arbad ◽  
Fernando Rincon ◽  
Catalin Teodoriu ◽  
Mahmood Amani

Abstract The catastrophic events faced by the Oil and Gas industry in the past depict the importance of maintaining the integrity of the well. The cement acts as a crucial barrier throughout the life cycle of the well. The contamination of the cement occurs due to inefficiency in cementing practices and operations. Experimental investigations have been done on the reduction in mechanical properties of different API class cement considering contamination with water-based mud and oil-based mud. This study focuses on analyzing the changes in mechanical properties of API Class C cement on varying the following parameters: OBM contamination (0%, 0.6%, 1.1%, 2.2%, 4.3%) Curing time (4 hrs, 6 hrs, 8 hrs, 1 day, 3 days, 7 days) Temperature (25˚C, 75 ˚C) API recommendations were followed for preparing the cement slurries. The destructive, as well as non-destructive tests were carried out on the cement samples at ambient room temperature to measure the uniaxial compressive strength (UCS) for OBM contaminated class C cement slurries. The general trend observed is that the UCS increases with an increase in curing time and temperature. UCS decreases with an increase in OBM contamination. Logarithmic trends were obtained for UCS vs curing time for different contaminations at a given temperature. Exceptions were observed at lower curing times where contaminated samples showed better results than the neat cement slurries. These observations play a critical role in understanding contaminated cement behavior. This widespread work was carried out only on API Class C cement to provide reliable data for future references. The correlations presented in this paper will help operators estimate the deterioration in mechanical properties of Class C cement in the presence of low OBM contamination. Email: [email protected] & [email protected]


2017 ◽  
Vol 139 (6) ◽  
Author(s):  
A. Dahi Taleghani ◽  
G. Li ◽  
M. Moayeri

One of the serious challenges encountered in cementing oil and gas wells is the failure of the cement sheaths and its debonding from casing or formation rock. Shrinkage of the cement during setting is identified as one of the driving factors behind these issues. Some expansive cement systems have been developed in the oil and gas industry to compensate for the shrinkage effect. All the expansive additives which have been developed so far have chemical reactions with the cement itself that would significantly impact the mechanical strength of the cement. In this paper, we present a new class of polymer-based expandable cement additive particles which are made of shape memory polymers (SMP). This class of polymers is designed to expand to the required extent when exposed to temperatures above 50–100 °C (122–212 °F) which is below the temperature of the cementing zone. It is notable that expansion occurs after placement of the cement but before its setting. The API RP 10 B-2 and 5 have been followed as standard test methods to evaluate expansion and strength of the cement slurry after utilizing the new additive. The proposed additive does not react with the water or cement content of the slurry. Mechanical evaluation tests confirm the potential benefit of this additive without any deteriorative effect on mechanical properties or setting time of the cement paste and significant impact on its mechanical properties. Hence, this additive would provide a reliable way to prevent cement channeling, debonding, and fluid migration to upper formations.


2020 ◽  
Vol 78 (7) ◽  
pp. 861-868
Author(s):  
Casper Wassink ◽  
Marc Grenier ◽  
Oliver Roy ◽  
Neil Pearson

2004 ◽  
pp. 51-69 ◽  
Author(s):  
E. Sharipova ◽  
I. Tcherkashin

Federal tax revenues from the main sectors of the Russian economy after the 1998 crisis are examined in the article. Authors present the structure of revenues from these sectors by main taxes for 1999-2003 and prospects for 2004. Emphasis is given to an increasing dependence of budget on revenues from oil and gas industries. The share of proceeds from these sectors has reached 1/3 of total federal revenues. To explain this fact world oil prices dynamics and changes in tax legislation in Russia are considered. Empirical results show strong dependence of budget revenues on oil prices. The analysis of changes in tax legislation in oil and gas industry shows that the government has managed to redistribute resource rent in favor of the state.


2011 ◽  
pp. 19-33
Author(s):  
A. Oleinik

The article deals with the issues of political and economic power as well as their constellation on the market. The theory of public choice and the theory of public contract are confronted with an approach centered on the power triad. If structured in the power triad, interactions among states representatives, businesses with structural advantages and businesses without structural advantages allow capturing administrative rents. The political power of the ruling elites coexists with economic power of certain members of the business community. The situation in the oil and gas industry, the retail trade and the road construction and operation industry in Russia illustrates key moments in the proposed analysis.


2019 ◽  
Vol 16 (6) ◽  
pp. 50-59
Author(s):  
O. P. Trubitsina ◽  
V. N. Bashkin

The article is devoted to the consideration of geopolitical challenges for the analysis of geoenvironmental risks (GERs) in the hydrocarbon development of the Arctic territory. Geopolitical risks (GPRs), like GERs, can be transformed into opposite external environment factors of oil and gas industry facilities in the form of additional opportunities or threats, which the authors identify in detail for each type of risk. This is necessary for further development of methodological base of expert methods for GER management in the context of the implementational proposed two-stage model of the GER analysis taking to account GPR for the improvement of effectiveness making decisions to ensure optimal operation of the facility oil and gas industry and minimize the impact on the environment in the geopolitical conditions of the Arctic.The authors declare no conflict of interest


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