Characterization of Baram and Tanjung sands as potential proppants

Baram and Tanjung sands were evaluated for potential use as proppants.Experiment was conducted on Baram and Tanjung sands following ISO and ASTM recommended standards.Results showed that Baram and Tanjung sand mineralogy is predominantly quartz with presence of metal oxides.Shape descriptors of both sands for sphericity and roundness were above 0.7.Baram sand was retained by 20/40 mesh size with mean size of 448.2 mm,bulk density of 1.32 g/cc,acid solubility of 1.5%and crush resistance of 4000 psi.While Tanjung sand was retained by 30/50 mesh size with mean size of 383.2 mm,bulk density of 1.30 g/cc,acid solubility of 1.20%and crush resistance of 8000 psi.This indicates that Baram sand has larger grain size that supports high permeability at low closure stress,making this sand suitable for shallow depth hydraulic fracturing operations,whereas Tanjung sand is more suitable for deeper domains with high closure stress.Experimental results and economic comparison with commercial frac sand and other proppant types support using Baram and Tanjung sands as potential proppants.

Evaluation of methyl ester sulphonate spacer fluid additive for efficient wellbore clean-up

Oil-based drilling fluid(OBDF)is used to drill through high permeable pay zone to prevent possible damage to the formation.However,the oil based drilling fluid leaves behind filter cake residue and oilwet surfaces which hinder cement bonding.Spacer fluid is usually introduced to clean up the wellbore prior to cementing job.This work presents a spacer fluid designed with environment-friendly anionic methyl ester sulphonate(MES)surfactant and evaluated through a series of experimental tests to ascertain its effectiveness to clean wellbore.Addition of methyl ester sulphonate to confected waterbased drilling fluid at high amount(0.15 g and 0.20 g)showed good rheological properties,compatibility with OBDF and cement and low contact angle on steel and sandstone in the range of 21.9°-34.7°.Furthermore,results show that it requires less amount of MES spacer fluid to revert oil-wet OBDF aqueous phase to water external continuous phase,validating the low contact angle measurements.Cleaning efficiencies for two best performing MES spacer fluids achieved 83.27%and 94.3%respectively.Shear bond strength were measured to be 1.3 MPa and 1.05 MPa for steel and sandstone respectively,above the minimum allowable shear bond strength for oil well cementing.Hence,MES spacer fluid can be used to clean up wellbores in high permeable formations and in well completion,where strong cement bonding is required.

A review on the mechanisms of low salinity water/surfactant/nanoparticles and the potential synergistic application for c-EOR

Chemical enhanced oil recovery(c-EOR)is a conventional and promising strategy to recover oil from reservoir techniques such as low salinity water flooding(LSWF),surfactant flooding,alkaline flooding,polymers flooding,and nanofluid flooding.The use of various types of chemical materials for c-EOR method has recently attracted the attention of the oil and gas industry.The primary objective of this review work is to explore the synergy of low salinity water/surfactant/nanoparticle flooding for effective c-EOR method and investigate the mechanism behind these methods.The advantages of combining these chemical materials for c-EOR methods is also reviewed.Challenges and limitations of this synergy and their economic feasibility for additional oil recovery and potential return on investment are reviewed.Nanoparticles have been successfully used in various applications in several industries and have also shown good application for EOR in terms of wettability alteration.LSWF contributes to wettability alteration,while surfactant contributes to wettability alteration and interfacial tension(IFT)reduction.However,fines migration caused by LSWF and nanoparticle agglomeration can cause formation damage,while excessive surfactant adsorption can lead to cost overrun on surfactant use.Understanding the characteristics of reservoir formation mineralogy and appropriate nanoparticle type,size,and concentration can be used to resolve this challenges.The synergy of LSWF and nanoparticles in alkaline medium can serve as sacrificial agent to reduce excessive surfactant loss.Therefore,the appropriate synergistic formulation of LSFW/surfactant/nanoparticle can improve additional oil recovery and support return on investment for c-EOR projects.

A methodology to improve nanosilica based cements used in CO2 sequestration sites

Attempts to reduce the amount of greenhouse gases released into the atmosphere in recent years have led to the development of Carbon Capture and Sequestration(CCS)technology.However,there have been many studies reporting leakages form CO2 storage sites as a result of cement degradation induced by generation of an acidic environment in the storage site.Although there are a number of approaches proposed to enhance the efficiency of the cement,the degradation issue has not been totally resolved yet perhaps due to the excessive corrosives nature of carbonic acid and supercritical CO2.The aim of this study is to propose a methodology to improve the physical and mechanical characteristics of the cement by nanomodification such that a consistent rheology,constant density and a good strength development can be achieved.A new dispersion technique was proposed to ensure that the cement formulation gives a consistent result.The results obtained indicated that unlike the literature mixing,cement slurries prepared by the new mixing technique are very consistent in their rheology,regardless of the sonication parameters chosen.The measurements of the compressive strength performed at the reservoir condition revealed that nanosilica contributes in the strength development up to a certain point.Thermogravimetric Analysis(TGA)conducted at the last stage indicated that the amount of Portlandite left in the cement by adding nanosilica is decreased due to the pozzolanic reaction,which would help the cement to have a higher chance of survival in a storage site.However,cautions must be taken to maintain a certain amount of Portlandite in the cement for slowing down the carbonation rate,as otherwise the matrix of the cement is attacked directly and the cement will be degraded very fast.