A Comparative Study of Mechanical Properties of Density-Reduced Cement 
Compositions

Ravi, Kris; McMechan, D.E.; Reddy, B.R.; Crook, R.J.

doi:10.2523/90068-ms

Cited by 13 publications

(7 citation statements)

References 11 publications

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“…Also, preventing the loss of fluids to the formations and proper well cementing have become critical issues in well construction to ensure wellbore integrity because of varying downhole conditions (Ravi et al, 2007;Eoff et al, 2009;Labibzadeh et al, 2010). Moreover, the environmental friendliness of the cements and real time monitoring are critical issues that is oil well cement serves many purposes in the deep water drilling projects .…”

Section: Introductionmentioning

confidence: 97%

Iron Nanoparticle Modified Smart Cement for Real Time Monitoring of Ultra Deepwater Oil Well Cementing Applications

et al. 2015

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Better controls during well drilling and cementing operation are critical to ensure safety during construction and the entire service life of the wells. For a successful cementing operation determine the setting of cement in place length of cement supporting the casing and performance of the cement after hardening. At present there are no technologies available to monitor the cementing operations without using buried sensors that could weaken the cement sheath.In this study, smart cement with 0.38 water-to-cement ratio was modified with Iron nanoparticles (NanoFe) to have better sensing properties, so that its behavior can be monitored at various stages of construction and during the service life of wells. A series of experiments evaluated the smart cement behavior with and without NanoFe in order to identify the most reliable sensing properties that can also be relatively easily monitored. Tests were performed on the smart cement from the time of mixing to hardened state behavior. During the initial setting the electrical resistivity changed with time based on the amount of NanoFe used to modify smart oil well cement. A new quantification concept has been developed to characterize cement curing based on electrical resistivity changes in the first 24 hours of curing. When cement was modified with 0.1 percent of conductive filer (CF), the piezoresistive behavior of the hardened smart cement was substantially improved without affecting the rheological and setting properties of the cement. For the smart cement the resistivity change at peak stress was about 2000 times higher than the change in the compressive strain after 28 days of curing.The shear thinning behavior of the smart cement slurries with and without NanoFe at two different temperatures (25°C and 85°C) have been quantified using the new hyperbolic model and compared with another constitutive model with three material parameters, Vocadlo model. The results showed that the hyperbolic model predicated the shear thinning relationship between the shear stress and shear strain rate of the NanoFe modified smart cement slurries very well. Also the hyperbolic model has a maximum shear stress limit were as the other model did not have a limit on the maximum shear stress. Based on the hyperbolic model the maximum shear stresses produced by the 0 percent, 0.5 percent, and 1 percent of NanoFe at temperature of 25°C were 175 Pa, 224 Pa, and 298 Pa, respectively. The maximum shear stresses produced by the 0 percent, 0.5 percent, and 1 percent of NanoFe at temperature of 85°C were 349 Pa, 377 Pa and 465 Pa respectively. Additional of 1 percent NanoFe reduced the initial resistivity of the smart cement by 16 percent. In a 24-hour period the maximum change in the electrical resistivity (RI 24 hr) for the smart cement without NanoFe was 333 percent. The RI 24hr for the smart cement with NanoFe increased with the amount of NanoFe. Addition of 1 percent NanoFe increased the compressive strength of the smart cement by 26 percent and 42 percent after 1 day and 28 days of curin...

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Section: Introductionmentioning

confidence: 97%

Iron Nanoparticle Modified Smart Cement for Real Time Monitoring of Ultra Deepwater Oil Well Cementing Applications

et al. 2015

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“…In various industries, 'endurance limit' is the term coined for the stress below which the material can withstand a large number of stress cycles. Cement mechanical properties, such as Young's modulus, tensile strength, and compressive strength, by themselves are not sufficient to determine integrity of the cement sheath (Ravi et al 2007). Cement sheath failure cycle under cyclical loading could be determined from lab experiments.…”

Section: Introductionmentioning

confidence: 99%

HPHT Cement Sheath Integrity Evaluation Method for Unconventional Wells

Shadravan

Schubert

Amani

et al. 2014

Day 2 Tue, March 18, 2014

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Chances of cement sheath failure increase considerably when the application involves deepwater, high pressure high temperature (HPHT) conditions. Such failures may occur as a result of temperature and pressure-induced stresses created by well events such as hydraulic fracturing, cyclic steam injection, steam assisted gravity drainage (SAGD), production, completion, or other remedial treatments. Thermal and stress cycles could impose the risk of losing zonal isolation and lead to delay in hydrocarbon production.Cement mechanical properties measurment solely would not be sufficient to predict the failure threshold of a cement sheath. Some experimental studies were conducted about the effect of cyclical loading on the integrity of casing and drill strings but less research have been done about the in situ cement sheath integrity under cyclical loading. This paper introduces a new Ultra HPHT experimental set up and an applicable method to evaluate cement sheath integrity under cyclical loading. It also provides insights to find the cement fatigue failure cycle for the set cement at elevated pressures and temperatures.This system was built and completed by benefiting from the capabilities of an extreme HPHT Rheometer. Cement samples could be cured for number of hours in the newly developed HPHT cell and then instantly tested under cyclical loading in various scenarios at high temperatures. The cement sheath fails after a certain number of cycles when reaches its fatigue endurance limit. This research showcases scenarios in which the fatigue failure cycles were identified for 1,000 psi, 2,000 psi and 5,000 psi, pressure differentials between the confining pressure (exposed to outside of the sheath) and the casing pressure. During these experiments, the confining pressure and temperature were held constant at 15,000 psi and 330 ̊ F while the casing pressure varied cyclically between 15,000 psi and 16,000 psi (Set A), 17,000 (Set B) and 20,000 (Set C). A stable chemistry of Class H cement plus 35% silica was used to prevent cement retrogression. Cement sheath failures such as radial cracking, debonding and disking occured due to cyclical loadings. Finally, a fatigue failure envelope was generated by the obtained data. This curve represents the extent of cement sheath endurance at HPHT conditions under cyclical loading.

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“…To guaranty cement sheaths integrity one should consider the cement sheath properties, taking into account the effects of well operations, the cement slurry design and testing, the cement slurry placement, and the cement sheath evaluation (CSE) 1 . This paper focuses CSE in nonconventional environment from the end users point of view.…”

Section: Introductionmentioning

confidence: 99%

Cement Sheath Evaluation in Nonconventional Environment—Case History

Paula

Rodrigues

Vicente³

2007

All Days

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fax 01-972-952-9435. AbstractSonic and ultrasonic tools have been widely used for cement sheath evaluation along the last decades. The evaluation main goal is the definition of the presence of cement in the annulus and its ability of promoting hydraulic isolation among different permeable zones, regardless of its density, compressive strength or even quality of the slurry. The challenges interpreting those logs are enormous because the influence of many variables in the acoustic signal. The difficulties increase dramatically if the well configuration is not conventional. In those cases, huge mistakes can occur requiring from the interpreter experience, understanding of the tools and acoustic principles, and detailed information about the well, casing, cement, and so on. The paper describes in detail three well documented cases histories where nonconventional conditions in the wellbore prevailed and required extreme care and experience to obtain the correct log interpretation. The first case reports the evaluation of an annulus with cement between two concentric casings; the disturbances caused by reflections from the second interface in the CBL signal are discussed and recommendations presented to bypass this obstacle. In the second case, the challenges to evaluate the cement sheath in a fiber glass casing are presented; usually in this case, the first signals arriving at the receiver do not come from the casing. Finally, the last case history describes the difficulties to come up with the right evaluation logging a liner cemented with lightweight slurry. For all cases, guidelines and recommendations are suggested to avoid misinterpretations and assure correct decisions about cement sheath evaluation.

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A Comparative Study of Mechanical Properties of Density-Reduced Cement Compositions

Cited by 13 publications

References 11 publications

Iron Nanoparticle Modified Smart Cement for Real Time Monitoring of Ultra Deepwater Oil Well Cementing Applications

Iron Nanoparticle Modified Smart Cement for Real Time Monitoring of Ultra Deepwater Oil Well Cementing Applications

HPHT Cement Sheath Integrity Evaluation Method for Unconventional Wells

Cement Sheath Evaluation in Nonconventional Environment—Case History

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