Mass transfer of H2O between petroleum and water: Implications for oilfield water sample quality

McCartney, Ross; Østvold, Terje

doi:10.1016/j.apgeochem.2005.04.013

Cited by 8 publications

(3 citation statements)

References 11 publications

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“…• Uncertainties in the prediction of the scaling potential from a particular field, which may relate to uncertainties in the initial formation water composition 5,9,10,11 and the spread different water chemistries which may be present in particular fields. 12,13,14 Therefore, although the current commercial scale prediction packages are generally regarded as being relatively reliable at accurately predicting the degree of over saturation, the quality and representativeness of available water chemistry data used as input into the models may be relatively inaccurate.…”

Section: Overview Of Technical and Economic Risk Based Analysismentioning

confidence: 99%

“…For example, water samples collected during the appraisal phase from gas production zones can have significantly different water compositions from those collected from oil production zones as a result of water partitioning into the hydrocarbon phases. 10,11 Whereas for many marginal fields, it is often difficult to obtain additional good quality downhole water samples and therefore a relatively large degree of uncertainty has to be carried into any technical analysis. For many high profile fields especially some of the massive deepwater facilities, the costs associated with scale management and the impact this can have on a fields economic success means that the case for additional water sampling can be more easily made.…”

Section: Risk Assessment and Economic Analysismentioning

confidence: 99%

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Technical and Economic Analysis of the Downhole Scale Risks and Uncertainties for Subsea and Deepwater Field Developments

Graham¹,

Collins

Johnson³

2005

All Days

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Scale control is conventionally achieved by the use of chemical inhibitors, introduced to the production system either by squeeze treatment into the reservoir or continual injection into the well.However, as new field developments encounter more challenging production environments or when the associated economic impact of chemical intervention is large (e.g. subsea completed wells with poor chemical placement by bullhead treatments, or limited access to wet subsea wellheads), other methods of scale control such as sulfate removal must be considered during the front end engineering design (FEED) stage for the development. However, the final selection of a fields scale management strategy relies on various technical and economic factors which themselves are controlled not just by the severity of the anticipated scaling regimes but also on the proposed field development plan.For subsea completed wells, especially those located in deepwater, the initial field development concept and drainage strategy can have a significant bearing on the costs ultimately associated with various scale management strategies and can, in extreme cases, significantly reduce the Net Present Value (NPV) of the project.The decisions taken at the concept selection stage for scale management in such environments are therefore crucial to the success not only of the chosen scale management strategy but also to the fields economic viability. This paper reviews the various challenges associated with scale formation and control in subsea and deepwater environments and the impact that different field design scenarios may have on the potential success of various scale management options. In particular, the paper will focus on technical, economic and risk-based analysis conducted for a number of new and proposed subsea field developments with different scaling challenges.The options for scale management in selected subsea and deepwater developments including examples from the North Sea (Shallow water), offshore Angola, and Gulf of Mexico cases will be reviewed.The impact of the various risks and uncertainties associated with determining the severity of the scale challenge (including the quality and source of initial water compositions, the accuracy of simulation tools used for the prediction of future scaling challenges prior to field production, the ability to effectively squeeze treat and place scale inhibitors into particular wells and the potential for changes in the field drainage strategy) are assessed in terms of the total costs associated with particular cases.In summary, the paper will describe the decision process used at the pre-FEED stage to determine a field scale management strategy for different development concepts.Detailed economic analysis of different options considered in recent field cases will be presented to support the different strategies adopted.

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Section: Overview Of Technical and Economic Risk Based Analysismentioning

confidence: 99%

Section: Risk Assessment and Economic Analysismentioning

confidence: 99%

Technical and Economic Analysis of the Downhole Scale Risks and Uncertainties for Subsea and Deepwater Field Developments

Graham¹,

Collins

Johnson³

2005

All Days

View full text Add to dashboard Cite

show abstract

“…For gas production systems however evaporation of water (H 2 O) represents a further mechanism for carbonate scaling due to increased scaling ion concentrations in the residual brine phase. 2,3 The high temperatures associated with the HP/HT fields give rise to very rapid reaction kinetics and hence the propensity for scale formation remains high even at moderate levels of oversaturation. Field experience indicates that wells producing at temperatures in the region of 85 o C may be operated safely at SR up to 2.5 [SR = saturation ratio = Ip/Ksp = ion product /solubility product] whereas for wells operating at higher reservoir temperatures field scale formation can occur when the SR is lower e.g.…”

Section: Introductionmentioning

confidence: 99%

Scale-Dissolver Application Under HP/HT Conditions -- Use of an HP/HT "Stirred Reactor" for In-Situ Scale-Dissolver Evaluations

Williams¹,

Wat

Chen³

et al. 2005

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In several high temperature and high pressure (HT/HP) production environments severe downhole carbonate scale formation is often anticipated and effective carbonate scale dissolvers are required. However for most cases the selection of scale dissolvers is conducted under much less severe conditions, involving simple bottle tests conducted at temperatures up to 95 o C and ambient pressure. These tests although generally accepted for screening purposes suffer a number of significant limitations. In addition to the moderate test conditions the low pressure means that carbon dioxide is readily released following the dissolution and results in changes in the test pH which may mean the efficiency of the dissolvers could be overstated. This paper describes the use of a novel a novel HP/HT "stirred reactor" test rig to more closely examine the relative performance of selected scale dissolvers including organic acids (formic and acetic acids), inorganic acids (16% HCl) and other more conventional scale dissolvers under typical field application conditions. The equipment is specially designed for the extraction and stabilisation of samples at or 'near' tested conditions and therefore allows the equilibrium dissolution level to be determined under more representative HP/HT conditions.In this work preliminary tests were conducted using 16% HCl under progressively more severe test conditions (RT & 1,500 psi; 150 o C & 1,500 psi and then 150 o C & 4,500 psi. Further tests were then conducted to compare the performance of organic acid based scale dissolvers (formic acid and acetic acid based products) together with other selected scale dissolvers at 150 o C and 4,500 psi and compared with the results obtained for 16% HCl. For these HP/HT tests, samples were collected and analysed after 2 and 20 hours equilibration time and results were compared with those obtained in more conventional "bottle tests conducted at less severe environmental conditions (90 o C and ambient pressure).In summary the results demonstrate the importance of conducting scale dissolver tests for field applications under more representative (HP/HT) conditions.Of particular significance was the impact of the cooling and pressure reductions. For one of the products tested, although very good dissolution was recorded under the HP/HT conditions, reprecipitation of a different polymorph of calcium carbonate occurred very rapidly resulting in a significant increase in the volume of carbonate precipitation within the reaction vessel and various sample lines. The paper will describe the details of the test equipment used in this work and present a mechanistic interpretation of the various results obtained. TX 75083-3836, U.S.A., fax 01-972-952-9435.

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Antiscalants and Their Compatibility with Corrosion Inhibitors

Wang

Chen

2020

Corrosion Inhibitors in the Oil and Gas Industry

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Mass transfer of H2O between petroleum and water: Implications for oilfield water sample quality

Cited by 8 publications

References 11 publications

Technical and Economic Analysis of the Downhole Scale Risks and Uncertainties for Subsea and Deepwater Field Developments

Technical and Economic Analysis of the Downhole Scale Risks and Uncertainties for Subsea and Deepwater Field Developments

Scale-Dissolver Application Under HP/HT Conditions -- Use of an HP/HT "Stirred Reactor" for In-Situ Scale-Dissolver Evaluations

Antiscalants and Their Compatibility with Corrosion Inhibitors

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