New Formulation for Iron Sulfide Scale Removal

Author(s):  
Salaheldin Elkatatny
2019 ◽  
Author(s):  
A. Onawole ◽  
I. Hussein ◽  
M. Saad ◽  
M. Ahmed ◽  
S. Aparicio

2021 ◽  
Vol 35 (18) ◽  
pp. 14401-14421
Author(s):  
Ahmed Hamza ◽  
Ibnelwaleed A. Hussein ◽  
Rem Jalab ◽  
Mohammed Saad ◽  
Mohamed Mahmoud

2019 ◽  
Vol 11 (23) ◽  
pp. 6727 ◽  
Author(s):  
Hany Gamal ◽  
Khaled Abdelgawad ◽  
Salaheldin Elkatatny

Iron sulfide scale is a common problem in the oil and gas industry. The precipitation of the iron sulfide scale on the well completion tools or inside surface flow lines restricts the flow of the produced fluids and might affect the integrity of the pipelines or the surface and subsurface tools. Failure of the downhole completions tools will not only reduce the production rates but it might require workover and remedial operations that will add extra cost. The main objective of this paper is to evaluate a new environmentally friendly acid system (NEFAS) for iron sulfide scale removal using an actual field sample. The scale sample collected from a natural gas well is dominated by pyrrhotite (55%) in addition to calcite (21%), pyrite (8%), and torilite (6%) with minor traces of hibbingite, siderite, geothite, akaganeite, and mackinawite. High-temperature solubility tests were performed by soaking 2 g of the scale field sample with 20 cm3 of the NEFAS under static condition at 125 °C for different time periods (2, 6, 12, 18, and 24 h). The solubility results were compared with commercial solutions for iron sulfide scale removal such as hydrochloric acid (15 wt.%), glutamic acid diacetic acid (GLDA, 20 wt.%), and high density converters (HDC-3) under the same conditions. The corrosion test was performed at 125 °C for the developed solution after mixing with 2 wt.% corrosion inhibitor (CI) and 2 wt.% corrosion intensifier (CIN). The results were compared with HCl (15 wt.%) under the same conditions. NEFAS consists of 75 wt.% biodegradable acid at pH of 0.04. NEFAS achieved 83 g/L solubility of iron sulfide scale after 6 h at 125 °C under static conditions. The solubility efficiency was very close to 15 wt.% HCl after 24 h where the solubility was 82 and 83 g/L for NEFAS and HCl, respectability. HDC-3 and GLDA (20 wt.%) achieved a lower scale solubility; 18 g/L and 65 g/L respectively, after 24 h. NEFAS achieved a corrosion rate of 0.211 kg/m2 after adding the CI and and CIN compared to 0.808 kg/m2 for HCl. The new environmentally friendly biodegradable acid system provides efficient performance for the scale removal without harming the environment and causing any side effects to the operation.


2018 ◽  
Author(s):  
Mohamed Abou Bakr ◽  
Ahmed Farid Ibrahim ◽  
Hisham Nasr-El-Din ◽  
Ahmed Abd El-Hay ◽  
Ehab Amin

SPE Journal ◽  
2021 ◽  
pp. 1-23
Author(s):  
Raja Ramanathan ◽  
Hisham A. Nasr-El-Din

Summary Issues such as high corrosion rate, hydrogen sulfide (or H2S) generation, and scale reprecipitation have required the use of alternative dissolvers such as tetrakis(hydroxymethyl)phosphonium sulfate (THPS)–ammonium chloride (or NH4Cl) blend and chelating agents to dissolve iron sulfide (or FeS) scales. However, there are many aspects of these dissolvers that need investigation. This paper provides a guideline to select the best dissolver under various oilfield conditions by an extensive laboratory study. Furthermore, the iron sulfide scale removal is enhanced by the use of new synergists to the chelating agents. The application of THPS and diethylenetriaminepentaacetic acid (DTPA) in well tubulars or pipelines requires laboratory testing to determine the optimal conditions such as dissolver concentration, treatment time, and dissolver/scale (D/S) ratio (cm3/g) at 150°F. This evaluation considers oil-wet scales, mixed scales, presence of additives, and presence of salts during the treatment. Synergists such as potassium chloride (or KCl), potassium iodide (or KI), potassium formate (or HCOOK), sodium fluoride (or NaF), and potassium citrate (or K-Citrate) were added to ethylenediaminetetraacetic acid (EDTA), DTPA, and hydroxyethylethylenediaminetriacetic acid (HEDTA), and the scale solubility was evaluated at 150 and 300°F. Inductively coupled plasma–optical emission spectrometer analysis of the supernatant solution at various intervals of time up to 48 hours revealed the kinetics of the dissolution process. H2S generated from the scale dissolution process was measured using Draeger tubes. Corrosion tests helped in measuring the damage to the tubulars as a result of the dissolver’s contact with N-80coupons. Solubility tests indicated the dissolver’s scale removal capacity at different concentrations. The work also accounted for the consumption of the dissolver for the scale removal. The optimal blend was chosen considering both the dissolution capacity and the dissolver consumption. For THPS–ammonium chloride blend, 0.75 mol/L THPS (30 wt%) and 2 mol/L NH4Cl (10 wt%) proved to be the optimum dissolver concentration at 150°F. Similarly, for DTPA, 0.4 mol/L K2-DTPA was evaluated to be the most effective dissolver concentration. The THPS–ammonium chloride blend was found to dissolve the iron sulfide slowly compared with K2-DTPA and 15% hydrochloric acid (HCl). The presence of crude oil on the scale hindered its solubility with K2-DTPA by 8%. The presence of calcium carbonate influenced higher selectivity of chelating the calcium ions by K2-DTPA. However, the overall fraction of scale removal was not affected. Adding corrosion inhibitors (CIs) did not affect the scale solubility significantly and also helped in maintaining an acceptable corrosion rate of N-80 coupons below 0.05 lb/ft2 at 150°F. The reaction of HCl and the iron sulfide scale generated 1,800 ppm of H2S in comparison with 0- and 10-ppm by THPS–ammonium chloride blend and K2-DTPA, respectively. Adding potassium iodide and potassium citrate to EDTA helped in improving the scale solubility at 150°F. Sodium fluoride improved the scale dissolution by EDTA and DTPA at 300°F. This paper addresses oilfield-like conditions on scale solubility by evaluating the role of mixed scale, scale mass, presence of hydrocarbons on the scale, and presence of monovalent/divalent ions in dissolver solution. A detailed and direct comparison of HCl, THPS–ammonium chloride blend, and DTPA in dissolving iron sulfide at various conditions enables easier selection of the dissolver for a field treatment. New synergists for iron sulfide scale dissolution are introduced in this paper. This work can help oilfield companies understand the nuances of applying different alternative iron sulfide dissolvers.


Author(s):  
Thao A. Nguyen

It is well known that the large deviations from stoichiometry in iron sulfide compounds, Fe1-xS (0≤x≤0.125), are accommodated by iron vacancies which order and form superstructures at low temperatures. Although the ordering of the iron vacancies has been well established, the modes of vacancy ordering, hence superstructures, as a function of composition and temperature are still the subject of much controversy. This investigation gives direct evidence from many-beam lattice images of Fe1-xS that the 4C superstructure transforms into the 3C superstructure (Fig. 1) rather than the MC phase as previously suggested. Also observed are an intrinsic stacking fault in the sulfur sublattice and two different types of vacancy-ordering antiphase boundaries. Evidence from selective area optical diffractograms suggests that these planar defects complicate the diffraction pattern greatly.


2018 ◽  
Vol 4 (3) ◽  
pp. 483-487
Author(s):  
Yousef Ahmed Alomi ◽  
Hussam Saad Almalki ◽  
Aisha Omar Fallatah ◽  
Awatif Faraj Alshammari ◽  
Nahedh Rashed Alotaibi

The general administration of pharmaceutical care started potential pharmacy practice program. The program is part of accreditation professional’s process of national and international regulations. The adult’s parenteral nutrition was one of the critical programs. The most healthcare professionals are not familiar with the new system. The new initiatives system adult’s standardized concentration formulation of total parental nutrition as complementary to the previous one. The new formulation consisted of all parental nutrition requirements based on national and international standards. The new system can be converted as computerized physician orders. The new initiatives may implement as project management model over one year or less than that’s. The new system prevents nutrition-related problems, and medication errors, and improve clinical outcomes of the adults’ population in the Kingdom of Saudi Arabia.


MISSION ◽  
2019 ◽  
pp. 54-57
Author(s):  
Marco Riglietta ◽  
Paolo Donadoni ◽  
Grazia Carbone ◽  
Caterina Pisoni ◽  
Franca Colombi ◽  
...  

In Italy, at the end of the 1970s, methadone hydrochloride was introduced for the treatment of opioid use disorder, in the form of a racemic mixture consisting of levomethadone and dextromethadone.In 2015 Levometadone was introduced, a new formulation marketed in Italy for the treatment of opioid use disorder in 2015.The article aims to bring the experience of an Italian Addiction Centre back to the use of this new formulation in the "real life" analyzing the efficacy, the trend of adverse events and pharmacological iterations in a context in which the treated population often uses besides the opiates, cocaine and alcohol, are burdened by a relevant physical and psychic comorbidity and frequently have a prescribed polypharmacy.


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