Investigating the expansion characteristics of geopolymer cement samples in a water bath and compared with the expansion of ASTM Class-G cement

Abstract

In selecting the binder composition for oil well application, its stability is an important design parameter. This paper presents the results of an experimental study conducted for comparing the linear expansion characteristics of geopolymer cement with the traditionally used ASTM Class G cement system. The expansion test was done in a water bath at 60 C subjected to different curing intervals. The linear expansion of a cement system defines as the dimensional changes occur in the system, which is sometimes required to avoid the cement shrinkage during the hydration phase. In the case when the desired level of expansion is not achieved in the system, then the commercially available expandable materials are added in the class G cement system that enables the system to expand to the desired level. Shrinkage in the cementing system causes the formation of a microannulus or induces a gap that may allow the migration of fluid, hence the integrity of the system could be lost. This experimental study has revealed that the geopolymer cement tends to expand 0.15%-0.2% without the addition of any admixture, whereas the ASTM Class G cement has shown a lower value of linear expansion, which was obtained less than 0.1% after 18 days of curing. In the case of Class G cement, the addition of expandable material helped to increase the expansion; in the case of a geopolymer system, the additive has further accelerated the expansion.

Experimental Study and Design of Experiment Using Statistical Analysis for the Development of Geopolymer Matrix for Oil-Well Cementing for Enhancing the Integrity

“…The observations on R additives' performance agreed with the results of researchers studying expandable materials to optimize the rheological characteristics and self-healing behavior of cement slurries. In 2020, Richhariya et al [20] published research on the cement slurry's rheological and self-healing characteristics using dual-coated polyacrylamide (DPAM). In their findings, cement slurry containing a 16% dosage of DPAM showed the optimal rheological characteristics and self-healing performance.…”

Effect of Elastomeric Expandable Additive on Compressive Strength and Linear Expansion of Fly-Ash-Based Strength-Enhanced Geopolymer Cement for Shrinkage-Resistant Oil-Well Cementing

“…Volumetric shrinkage of cement during hydration has always been a concern in oil-well cementing [13][14][15]. It instigates the formation of micro-annulus cracks due to contraction of the external dimensions of the cement [16,17] and de-bonding between the cement, casing and formation [18,19]. Elevation in the casing pressure is then induced as a result of the migration of gas and liquid from the formation [20,21] that, in due course, may lead to failure of the cement sheath.…”

“…The presence of gaps inside the cement sheath, between the casing and cement, and between the casing and formation facilitates the migration of fluid from the formation [22], where the fluid flows upward to the surface via flow paths. Sustained casing pressure (SCP) may occur owing to the accumulation of fluid underneath the wellhead [23] that can potentially lead to the loss of hydrocarbon reserves and pollution of the aquifer and sea [17]. Accordingly, wells that are subjected to SCP require work-over jobs that include the replacement of corroded tubes and remedial squeeze cementing.…”

“…Accordingly, wells that are subjected to SCP require work-over jobs that include the replacement of corroded tubes and remedial squeeze cementing. The process of dehydration would be employed to perform the replacement, which involves the injection of cement slurry into the leak paths [17]. Moreover, work-over jobs have been previously reported to be costly, with exorbitant rates that can reach USD 100,000 per well by virtue of the low success rate of earlier attempts prior to successfully attaining an adequate seal that is serviceable [24].…”

“…GPC has been accentuated in previous research as an alternative to OPC for oil-well cementing [1,17,20]. Previous research on the application of geopolymer for other civil engineering applications is wide-ranging.…”