The application and comparative study of calcined clay and nanoclaymixed cement slurries at hpht conditions

Mobeen Murtaza, Muhammad Rahman, Abdulaziz Abdulla Al Majed

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

fluid loss test was conducted at 50°C and1000 psi pressure. The uniaxial compressive strength (UCS) test was conducted for cement samples curedat 121°C temperature and 3000 psi pressure conditions for 24 hours and 5 days in HPHT curing chamber.Microstructural investigations were conducted using SEM analysis of cured samples. It was observed that addition of nanoclay and calcined clay in Class G cement enhanced the rheologicalproperties of cement slurries. The plastic viscosity increased with an increase in percentages of bothadditives. Higher values of yield point and plastic viscosity were obtained for calcined clay. In case fluidloss, a reduction in fluid loss was noticed for nanoclay. There was no appreciable change in fluid losswith the addition of calcined clay in mixes. Calcined clay-based cement slurries resulted in robust structureand sustained high compressive strength after exposure to high temperature high-pressure conditions. Thenanoclay-based mixesgave higher strength compared to Class G cement slurry but lower than calcinedclay. The compositional analysis showed that calcined clay gave low calcium/silica ratio and strong bondedstructure. This study will pave a way for researchers to study further the application of calcined clay in oil and gascementing and its long-term durability.,In oil and gas wells construction, the cement sheath in the annulus between casing and formation plays acritical role throughout the producing life of the oil and gas well. Under elevated conditions of temperatureand pressure, set cement changes its physical, chemical and mechanical properties. Sometimes these changescan lead to strength retrogression of cement. Recently, it was found that calcined clay (CC) and nanoclay(NC) significantly improve the hardened cement matrix properties as both materials have pozzolanicproperties. Both additives have characteristics such as acid and sulfate resistance, low heat of hydration,low density, low permeability and the formed phases with the higher thermal endurance. In this study, cement mixes with different percentages (1% & 2%) by weight of cement (BWOC) ofcalcined clay and nanoclay were investigated and compared with Class G cement slurry. Rheology, fluidloss and compressive strength properties of all cement slurries were measured.Rheological properties weremeasured at 50°C temperature and atmospheric pressure.

Original languageEnglish
Title of host publicationOffshore Technology Conference 2020, OTC 2020
PublisherOffshore Technology Conference
ISBN (Electronic)9781613997079
StatePublished - 2020
Externally publishedYes
EventOffshore Technology Conference 2020, OTC 2020 - Houston, United States
Duration: 4 May 20207 May 2020

Publication series

NameProceedings of the Annual Offshore Technology Conference
Volume2020-May

Conference

ConferenceOffshore Technology Conference 2020, OTC 2020
Country/TerritoryUnited States
CityHouston
Period4/05/207/05/20

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