Novel Sulfide Scale Inhibitor Successfully Averts Challenging Sulfide Scale Deposition in Permian and Williston Unconventional Basins

Author(s):  
Cyril Okocha ◽  
Alex Thornton ◽  
Jonathan Wylde
2014 ◽  
Author(s):  
Tao Chen ◽  
Ping Chen ◽  
Harry Montgomerie ◽  
Thomas Hagen ◽  
Ronald Benvie ◽  
...  

Abstract Turbulent flow, especially around chokes, downhole safety valves and inflow control devices, favors scale deposition potentially leading to severe loss of production. Recently, scale formation under turbulent conditions has been studied and progressed, focused on the bulk precipitation (SPE164070) and a small bore valve loop test (SPE 155428). However, bulk precipitation is not fully representative the surface deposition in the fields and the Reynolds number of modified loop is unknown. The relationship between a measured Reynolds number and surface deposition up until this study has not been addressed. A newly developed test methodology with rotating cylinder has been applied to generate high shear rate and evaluate surface deposition with Reynolds numbers up to ~41000. The relationship between Reynolds number and surface deposition is addressed. Using this highly representable test method for BaSO4 scale deposition, several different generic types of inhibitor chemistries, including polymers and phosphonates, were assessed under different levels of turbulence to evaluate their performance on surface deposition. The results showed it is not always true that higher turbulence results in higher dose of inhibitor being required to control scale. It is inhibitor chemistry and mechanisms dependent. The scale inhibitorscan be classified as three types when evaluating the trend of mass deposition versus Reynolds number and the morphology of the crystals deposited on the metal surface. ➢ Type 1: Crytal growth inhibitors. The mass of surface deposition increases with the increase of turbulence, along with smaller crystals.➢ Type 2: Dispersion and crystal growth inhibitor. The higher the turbulence, the less mass deposition, along with smaller crystals.➢ Type 3: Dispersion scale inhibitors. The higher the turbulence, the less mass deposition. The size of the crystals has no major change. This paper gives a comprehensive study of the effect of flow condition on the scale surface deposition and inhibition mechanisms. In addition, it details how this methodology and new environmentally acceptable inhibitor chemistry can be coupled to develop a chemical technology toolbox that also includes techniques for advanced scale inhibitor analysis and improved scale inhibitor retention, to design optimum scale squeeze packages for the harsh scaling conditions associated with turbulent flow conditions.


2014 ◽  
Author(s):  
E.. Sørhaug ◽  
M.M.. M. Jordan ◽  
R.A.. A. McCartney ◽  
R.. Stalker ◽  
E.J.. J. Mackay ◽  
...  

Abstract The Blane field is a sub-sea oil and gas production development located in the southern part of the North Sea straddling the UK and Norwegian border. The field is expected to produce inorganic scale (BaSO4) when injection water containing sulphate breaks through in the production wells. This will require scale inhibitor squeezes from an intervention vessel to mitigate scale deposition. The wells were completed with long horizontal sections straddling multiple producing zones. This could potentially result in scale deposition severely reducing productivity if both formation water and injection water were to be produced simultaneously into the wells. Adding to the complexity, the perforation guns were left in the wellbore as part of the completion preventing any access to the perforation area. The distribution of scale inhibitor during a squeeze pumping operation could therefore be uneven leaving parts of the well poorly protected. In addition, the guns prevent physical removal of any type of materials in the well bore like asphaltenes, sand and scale which could plug off the perforations during a pumping operation with a well intervention tool; Wireline, coiled tubing, etc.. Injection water supplied from a host platform is used for pressure support of the reservoir. During the field development, the injection water was expected to contain mostly produced water reducing the scale potential considerably as it would have low sulphate content. When water injection started, very little produced water was being produced resulting in mostly seawater being available available for pressure support. Scale deposition in the well and around the well bore could therefore prove to be impossible to control unless reactions in the reservoir would reduce the scale potential or a reliable scale inhibitor squeeze method to mitigate scaling could be identified. This paper describes the joint effort of 6 different companies to identify the risks associated with the inorganic scaling during production and how a scale squeeze strategy was developed. The work included scale inhibitor selection, a geo-chemical study, and reservoir and near well bore simulations, sub-sea deployment selection, deciding on water chemistry and production monitoring and development of an overall management plan.


2014 ◽  
Author(s):  
O.. Vazquez ◽  
T.. Chen ◽  
L.. Crombie ◽  
P.. Chen ◽  
S.. Heath ◽  
...  

Abstract One of the most common methods to prevent scale deposition in the near wellbore area is through the application of squeeze treatments which conventionally consist of pre-flush, main treatment, overflush, shut-in and back production stages. The use of additives such as polyamino acids and polyquaternary amines has often been successfully applied as part of the pre-flush stage of squeeze treatments to improve treatment lifetimes (Chen et al., 2006, Vazquez et al., 2011, Heat et al., 2012). However, although this technology has been successful applied in the field, there is still a lack of understanding of the prevalent retention mechanisms with different scale inhibitors and also a suitable test methodology and modelling techniques to optimize field treatment designs and lifetimes. A new sand pack methodology which provides a better simulation of field squeeze treatments than traditional corefloods has been designed to provide a better understanding of the scale inhibitor retention mechanisms when polyquaternary amines are applied in pre-flush treatments. This has enabled improved treatment modelling and the impact of these additives to be understood in field treatments. The performance of the polyquaternary amine is dependent upon scale inhibitor chemistry and the mechanisms of retention are addressed for both polymeric and phosphonate scale inhibitors. The adsorption isotherms were derived and compared in the absence/presence of the polyquaternary amine using specialized software, and applied to predict squeeze lifetime in field scenarios. This paper provides an understanding on the effects of polyquaternary amines on squeeze lifetime for both phosphonate and polymeric scale inhibitors supported by the application of a newly developed test methodology and computer modelling techniques. In addition, the combination of laboratory and computer modelling data coupled with field experience and a better understanding of the retention mechanisms involved now provides the ability to improve and optimize field squeeze treatment designs with polyquaternary amine pre-flush additives.


2014 ◽  
Author(s):  
O.. Vazquez ◽  
R.. Mehta ◽  
E.. Mackay ◽  
S.. Linares-Samaniego ◽  
M.. Jordan ◽  
...  

Abstract Shale developments are normally hydraulic fractured to stimulate the low permeability of the reservoirs, in order to allow fluid to flow to the wellbore. The most common fluid fracture deployed in shale developments is slickwater; which is typically composed volumetrically of approximately 95% water, 4% proppant and 1% other chemicals such as scale inhibitor, surfactant, biocide and corrosion inhibitor. Water management in shale plays accounts for 5% - 15% of total well completion costs. This study investigates the fate of fracturing fluids in shale developments and attempts to understand the effect of fracturing fluid trapped within the reservoir. Approximately 5% - 50% of fracturing fluid pumped is flowed back as the well is put on production. Scale deposition is often experienced within these wells due to the interaction of fracturing fluid lost to the formation reacting with formation brines. It is estimated that the formation of scale within the reservoir, blocks of nano-pores and reduces to some extent the fraction of fracturing fluid returned. The main purpose of this study was to simulate the post-frac flowback composition using a reactive transport model. The model simulates the injection of the fracture fluid, when in contact with the reservoirs minerals, a number of geochemical processes take place and with subsequent production further reactions are possible. The model was used to evaluate the possible causes of the high TDS content in the post-frac water, on one hand dissolution of salts present in the shale or the breaching of deep saline aquifers during fracturing. The value of this paper being to the industry is to increase the understanding of the geochemical reactions occurring during shale fracturing which will impact produced water reuse, scale inhibitor selection to prevent inorganic scale deposition resulting in better fracture performance.


Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 992 ◽  
Author(s):  
Maxim Oshchepkov ◽  
Vladimir Golovesov ◽  
Anastasia Ryabova ◽  
Svetlana Frolova ◽  
Sergey Tkachenko ◽  
...  

An attempt to reveal the mechanisms of scale inhibition with the use of two different fluorescent-tagged antiscalants at once is undertaken. To reach the goal, a novel 1,8-naphthalimide-tagged polyacrylate (PAA-F2) is synthesized and tested separately and jointly with 1,8-naphthalimide-tagged bisphosphonate (HEDP-F) as a gypsum scale inhibitor within the frames of NACE Standard TM0374-2007. Here, it is found that at a dosage of 10 mg·dm−3 it provides a much higher inhibition efficiency (96%) than HEDP-F (32%). A PAA-F2 and HEDP-F blend (1:1 mass) has an intermediate efficacy (66%) and exhibits no synergism relative to its individual components. The visualization of PAA-F2 revealed a paradoxical effect: an antiscalant causes modification of the CaSO4·2H2O crystals habit, but does not interact with them, forming particles of its own solid complex [Ca-PAA-F2]. This paradox is interpreted in terms of the “nano/microdust” concept, prioritizing the bulk heterogeneous nucleation step, while an ability of the scale inhibitor to block the nucleus growth at the next steps is proven to be of secondary importance. At the same time, HEDP-F does not change the gypsum crystals morphology, although this antiscalant is completely located on the surface of the scale phase. The PAA-F2 and HEDP-F blend revealed an accumulation of both antiscalants in their own [Ca-PAA-F2/Ca-HEDP-F] phase with some traces of HEDP-F and PAA-F2 on the CaSO4·2H2O crystals surface. Thus, the visualization of two different antiscalants separately and jointly applied to gypsum deposition demonstrates differences in phosphonic and polymeric inhibitors location, and a lack of causal relationship between antiscalant efficiency and scale particle habit modification. Finally, it is shown that the confocal microscopy of several fluorescent antiscalant blends is capable of providing unique information on their interrelationships during scale deposition.


2009 ◽  
Vol 113 (3) ◽  
pp. 1966-1974 ◽  
Author(s):  
Kun Du ◽  
Yuming Zhou ◽  
Liuqian Wang ◽  
Yingying Wang

Author(s):  
Bernardo Augusto Farah Santos ◽  
Rhuan Costa Souza ◽  
Maria Eduarda Dias Serenario ◽  
Eugenio Pena Mendes Junior ◽  
Thiago Araujo Simões ◽  
...  

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