Scale Prediction and Inhibition for Unconventional Oil and Gas Production

Fan, Chunfang; Kan, Amy T.; Zhang, Ping; Lu, Haiping; Work, Sarah; Yu, Jie; Tomson, Mason B.

doi:10.2118/130690-ms

Cited by 19 publications

(9 citation statements)

References 36 publications

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“…K sp , BaSO4 used in this study is consistent with those from the other two sources at temperature below 200 o C and most pressures. At 250 o C, the values in this study agree well with Blount's, in spite of the slightly greater discrepancy at higher pressure; the difference between Kharaka and SUPCRT92 appears more substantial, consistent with the observation by Kan and Tomson (2010).…”

Section: Resultssupporting

confidence: 91%

“…One major difficulty associated with scale prediction and control at these conditions is the inadequate understanding of thermodynamic properties of common minerals at the ranges of temperature, pressure and TDS routinely encountered in the productions (Fan et al 2010;Fan et al 2012;Kan and Tomson 2012). Model prediction of solubility of various minerals requires precise values of both equilibrium constants (including solubility product of the minerals (K sp ) and other association constants for complexes, if applicable) and activity coefficients.…”

Section: Introductionmentioning

confidence: 99%

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Modeling the Thermodynamic Properties of Common Minerals at High Temperature, Pressure and Salinity with Complex Ions

Shi

Zhang

et al. 2012

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The ultra-high temperature (150-250 o C), pressure (1,000-2,000 bar, 15,000 to 30,000 psi) and TDS (>300,000 mg/L) in deepwater oil and gas production pose significant challenges to scaling control due to limited knowledge of mineral solubility, kinetics and inhibitor efficiency at these extreme conditions. Prediction of thermodynamic properties of common minerals is currently limited by lack of experimental data and inadequate understanding of modeling parameters. In this study, a new apparatus was built to test scale formation and inhibition at high temperatures and pressures. Solubilities of two common minerals, barite and calcite, were tested at temperature up to 250 o C, pressure up to 1,500 bar (22,000 psi) and ionic strength up to 6m in solutions with elevated concentrations of mixed electrolytes (e.g., calcium, magnesium, sulfate and carbonate) representing the maximum range of interferences expected (95%CI) in oil and gas wells. As an attempt towards experimentally determining mineral solubility at high temperature, pressure and salinity, not only does this study contribute to the extremely limited data base, but it also provides a reliable approach for evaluating and adjusting model predictions at extreme conditions. Predictions by a thermodynamic model based on Pitzer's ion interaction theory were evaluated using experimental data. The dependence of Pitzer's coefficients for ion activity coefficients on temperature and pressure was examined and incorporated into the scale prediction model, whose prediction is consistent with both experimental and literature data at all conditions tested.

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Section: Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Modeling the Thermodynamic Properties of Common Minerals at High Temperature, Pressure and Salinity with Complex Ions

Shi

Zhang

et al. 2012

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“…Scale prediction of this brine sample using scale modeling software identified calcium carbonate as the predominant scale type. Theories and general operating guidance for the software can be found on the software website and in literature from Fan et al (2010) and Thomson et al (2009).…”

Section: Resultsmentioning

confidence: 99%

Combination Package Development of Scale Inhibitors and Hydrogen Sulfide Scavengers for Sour Gas Production in Barnett Shale

et al. 2015

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The Barnett Shale, a formation of~5000 mi 2 between the Bend Arch and Fort Worth Basin, was estimated the largest producible onshore reservoir for natural gas production in the United States. The field also features souring production and significant carbonate scale issues (predominated by CaCO 3 and FeCO 3 ). As common commercial triazine-based scavengers inevitably elevate the pH of production water, the need for continuous injection of such chemicals often elevates scaling risks to severe levels. For this purpose, combination treatment packages, including both scavengers and custom-tailored scale inhibitors, are preferred in the field. This paper presents the development of test methodology, the combination products, and the scale inhibitor performances of combination product.This study focuses on circuiting three major individual aspects in the testing system, including (A) a high-calcium brine, (B) scavenger chemistries, and (C) selection of scale inhibitors. During the investigation, B included five scavenger chemistries (two traditional triazine-based and three novel nonamine based), whereas C involved scale inhibitors (including both phosphonates and polymeric types). In a traditional quick testing, scale inhibitor performance is commonly evaluated with or without the occurrence of H 2 S scavenger. A systematic consideration of the interactions of all the counterparts is necessary for development of a treatment package with optimal field performance. First, the high-Ca brine caused incompatibility issues with all the scavengers (AϩB), the extent of which was not pH-dependent, but associated with the chemistries. The incompatibility was significantly mitigated by the addition of inhibitors, indicating potential synergetic effects of use of scale inhibitors in the combined scavenger packages. Second, the stability of inhibitors in the finished scavenger products was another issue (BϩC). Most phosphonate inhibitors exhibited significantly better results than the polymeric types. For scaling inhibition performance (AϩC with B), most published literature suggests it was driven by the elevated pH from the addition of triazine-based scavengers. However, this mechanism did not fully explain the impact of nontriazine scavengers on scale inhibition. For example, the inhibition efficiencies for calcite were measured differently at the same concentration of SI for two types of nonamine based scavengers, both having pH values of approximately 7. With a series of tests, combination packages were developed for each individual scavenger. With lab testing simulating the application scenarios in the field, all of the combined products demonstrated sufficient scale inhibition results.The observations presented in this work could contribute the selection of the H 2 S scavenger product for water stream or full stream applications, particularly if brine compatibility is a primary concern. Further study of the effects of various scale inhibitors on the brine/scavenger compatibility could lead to the development of new combo pro...

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“…Scale prediction of this brine sample using ScaleSoftPitzer™ (SSP) software identified calcite as the predominant scale type. The theories and general operating guidance for SSP software can be found on the software website (www.brinechem.rice.edu/node/47) and in the literature (Fan et al 2010;Tomson et al 2009). …”

Section: Resultsmentioning

confidence: 99%

Liquid Scale Inhibitors for Metallic-Crosslinked Gel Fracturing Systems

Yue

Lang

et al. 2014

SPE International Oilfield Scale Conference and Exhibition

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Scale inhibitors are important additives in fracturing fluids to help prevent mineral scale depositions during hydraulic fracturing, shut-in, and flowback stages. The inhibition mechanisms rely heavily on the interactions of certain functional groups from the inhibitor molecules and the lattice metals on the scale crystal surface. In stimulation using crosslinked gel fluids based on metallic crosslinkers, such as zirconium (Zr), titanium (Ti), or aluminum (Al), these metals form strong covalent bonds with guar and guar derivatives and therefore significantly increase overall gel stability. When anionic liquid scale inhibitors are present, the crosslinker metals are susceptible to attack from scale inhibitors because of similar interactions, often resulting in lower viscosity and compromised fluid performance. For this reason, liquid scale inhibitors are usually pumped in prepads during many fracturing treatments. During these treatments, fracturing fluids from other stages and reservoirs that contact these fluids are not protected from scale deposition. Although this incompatibility issue is an important factor in designing fracturing fluid systems, the authors have not found sufficient prior literature providing valid solutions other than applications of time-released solid scale inhibitors.This paper investigates the interferences of various types of liquid scale inhibitors on Zr-based crosslinkers. Their chemical compatibilities are evaluated in terms of crosslinked viscosity stability and scale inhibition efficiencies. Data presented in this paper indicate that two polymer-based liquid scale inhibitors can be added to selected Zr-crosslinked fluids with minimal impact on crosslinking performance. Scale inhibition efficiency can be maintained by adjusting the pumping flow rate to compensate for the effect of Zr-based crosslinkers.

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Scale Prediction and Inhibition for Unconventional Oil and Gas Production

Cited by 19 publications

References 36 publications

Modeling the Thermodynamic Properties of Common Minerals at High Temperature, Pressure and Salinity with Complex Ions

Modeling the Thermodynamic Properties of Common Minerals at High Temperature, Pressure and Salinity with Complex Ions

Combination Package Development of Scale Inhibitors and Hydrogen Sulfide Scavengers for Sour Gas Production in Barnett Shale

Liquid Scale Inhibitors for Metallic-Crosslinked Gel Fracturing Systems

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