Determination of Slurry’s Properties of Oil Well Cement Produced from Local Raw Materials

Oil well cementing is a critical step in well construction, where cement slurry is pumped into the annular space between the casing and the borehole wall to achieve zonal isolation, provide casing support, and ensure long-term well stability. This research investigates the slurry’s properties of oil well cement made from locally sourced raw materials, focusing on three types of cement: BUAC, POWCC, and newly developed Class G MSR cement (POWCGMSR). The POWCGMSR cement exhibited mineral compositions typical of Class G cement, including 54.47 wt% C₃S, 17.26 wt% C₂S, 5.82 wt% C₃A, and 15.72 wt% C₄AF, along with a specific surface area of 331 m²/kg, in accordance with API specifications and as supported by literature. Compressive strength testing revealed a reduction when 5% laterite was added, an effect attributed to the dilution of the C₃S and C₂S phases. However, strength increased over time with continued curing. All slurry formulations complied with API RP 10B-2 (2013) standards for rheology, with plastic viscosities ranging from 35 to 60 cP and yield points between 5 and 15 lb/100 ft². Setting time evaluations also met API 10A standards, with initial setting times exceeding 45 minutes and final setting times remaining below 600 minutes. Expansion testing showed that BUAC exceeded the API limit (>1.0%), indicating potential durability concerns, while POWCC and POWCGMSR remained within acceptable limits (<0.6%). Thickening time results were consistent with API guidelines: POWCC (140 minutes) is suitable for shallow wells (<3000 ft), BUAC (160 minutes) for intermediate depths (3000–8000 ft), and POWCGMSR (190 minutes) is also appropriate for intermediate wells, with potential for application in deeper wells. POWCGMSR was the most effective for fluid loss control and is suitable for use in critical wells because the addition of laterite acted as a pozzolanic material, which improved water retention. BUA Cement was deemed suitable for standard wells, though it could benefit from the addition of fluid loss control agents. POWCC, on the other hand, requires formulation improvements to enhance its fluid retention capacity.