Abstract The prediction of pH-dependent scales such as carbonates and sulfides presents unique challenges because their formation is strongly related to the three phase partitioning acid gases (CO2 H2S). A rigorous procedure required ensure proper modelling hydrocarbon phases, in order derive correct data input for software from available field data. Using this input, reliable scale calculations may then be run using either integrated or separate PVT software. Although some carbonate methods...

Abstract Predicting the formation of pH- dependent scales such as carbonates and sulphides requires a full calculation all hydrocarbon aqueous phases present to determine distribution speciation CO2 H2S in system. Several commercially available software packages combine PVT calculations with scale predictions, but are more targeted systems have limited capabilities. Likewise, modelling focusing on phase does not always fully model or can only predict number scales/complexes. Moreover, within...

Predicting the formation of pH-dependent scales requires full thermodynamic calculations compositions all hydrocarbon and aqueous phases present. This is necessary in order to determine distribution speciation CO2 H2S between gas, oil, water system. Several commercially available software packages combine PVT with scale predictions, but such are more targeted modeling systems often have limited capabilities. Likewise, focusing on phase does not fully model or can only predict a number...

Abstract Wells producing from an oilfield in Abu Dhabi were investigated to understand the CaCO3 scaling risk at current production conditions, and predict how downhole topside potential will change during a planned CO2 WAG project. The results of this study be used design correct scale inhibitor treatment for each phase. A rigorous prediction procedure pH dependent scales previously published by authors was applied using commercial integrated PVT aqueous modelling software package produce...

Abstract Unlike other CCUS technologies, CO2 EOR has been widely implemented at a commercial level and on an industrial scale. In EOR, can be injected its own or alternated with water in WAG (water-alternating-gas). Both applications have direct impact produced fluid compositions influencing GOR, cut, concentration consequently Ca2+, alkalinity pH. The variation of inevitable the scaling potential fluids resulting scale formation mitigation strategy. aim this work is to investigate changes...

Abstract Carbonate and sulphide scales can form in CO2 and/or H2S-rich environments a process which we refer to as "auto-scaling", i.e. these the produced brine due change conditions such pressure temperature, not mixing. Particularly production systems, carbonate evolution of H2S from aqueous phase gas caused by decrease. scale formation this manner is broadly understood; however, there are details precisely how occurs auto-scaling processes widely appreciated. Measuring water composition...

Abstract Microbial reservoir souring poses a significant threat to safe oil and gas production operations it is difficult control mitigate. Predicting future H2S trends with models done in an attempt define the worst-case scenario make critical decisions related asset field life. Unfortunately, these predictions often prove wrong because of large uncertainties around parameters used within predicting behaviour living microorganisms much more complex than dealing most other chemical...

Abstract An alkaline-surfactant-polymer (ASP) pilot in a regular five spot well pattern is underway the Sabriyah Mauddud (SAMA) reservoir Kuwait. High divalent cation concentrations formation water and high carbonate concentration of ASP formulation makes calcite scale concern. The main objective this study to investigate severity calcium (CaCO3) scaling issues central producer pursuit risk mitigation strategy treat potential deposition reduce flow assurance challenges. Calcite terms...

Abstract Calcium carbonate is a pH dependent inorganic mineral scale that influenced by CO2 and H2S partitioning. CaCO3 prediction must therefore include accurate modelling of the aqueous phase all hydrocarbon phases present. challenges development rigorous procedure for generation more results were previously published. This has now been applied to an onshore oilfield in Southeast Asia assessment management scaling. A workflow was ‘at-risk’ field producers showed scaling at and/or...

Summary Carbonate and sulfide scales are directly coupled together differ from other inorganic because they intimately linked to the in-situ concentrations of carbon dioxide (CO2) hydrogen (H2S), which influence local pH availability reactive species. The CO2 in aqueous solutions has most significant effect on system pH, solution content bicarbonate ion (HCO3–), final alkalinity. However, presence H2S also a direct important total-system When calcium carbonate deposition occurs depressurized...

Abstract The effects of H2S on system integrity, sulphide scaling potential and health safety in oil gas production is well recognized understood. However, as part a wider study pH dependent scale predictions, the authors have identified an additional challenge associated with presence and/or development reservoirs containing carbonates: higher concentration reflects calcium carbonate potential. intention this work to demonstrate impact using real field case scenario investigate how...

Summary Unlike other types of inorganic scales, carbonate and sulfide scales are directly correlated to the in-situ concentration acid gases such as carbon dioxide (CO2) hydrogen (H2S), which influence local pH availability reactive species. The common approach sulfide- carbonate-scale prediction often does not account for three-phase CO2 H2S partitioning at different temperatures pressures throughout system. This leads use inaccurate compositions values mineral-scaling calculations. In this...