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Salts/Sulphates/Scales
Scaling Issue in the Platform Area of Tengiz Field and Preventing Solutions
Myrzabayeva, A. (TengizChevroil, Atyrau, Atyrau region, Kazakhstan) | Kydyrgazy, A. (TengizChevroil, Atyrau, Atyrau region, Kazakhstan) | Sadyrbakiyev, R. (TengizChevroil, Atyrau, Atyrau region, Kazakhstan) | Kalzhekov, N. (TengizChevroil, Atyrau, Atyrau region, Kazakhstan) | Gaziz, D. (TengizChevroil, Atyrau, Atyrau region, Kazakhstan) | Orazov, B. (TengizChevroil, Atyrau, Atyrau region, Kazakhstan) | Williams, D. (TengizChevroil, Atyrau, Atyrau region, Kazakhstan) | Lu, H. (TengizChevroil, Atyrau, Atyrau region, Kazakhstan) | Yan, C. (Chevron, Houston, Texas, USA)
Abstract Even though most wells in the Tengiz Field produce virtually water free oil (less than 1% water cut), inorganic scales have been observed in many wells. Acid stimulation treatment programs for existing wells with deteriorated productivity include implementation of scale inhibitors, however this reactive approach might not always be the best way to proceed. The scope of the paper is to identify the main parameters which increase the probability of scale formation before a well is put on production and proactively treat such wells with scale inhibitors. Previously Tengizchevroil (TCO) has conducted an extensive research project to reduce the need for frequent acid treatments while maintaining well deliverability at sustained rates. Compatibility and core flood tests have been performed to choose the best scale inhibitor, and an extensive surveillance program has been developed to track residual inhibitor concentration to timely plan subsequent stimulation treatments. This paper covers the next step of the study and includes analysis of the recent cases of scale formation including identification of similar properties between the cases to enable forecasting of the tendency of all new wells to encounter scale formation. The study consists of three main steps – analysis of formation water and solid samples, analysis of open hole log data and analysis of production history for Tengiz and Korolev wells. The formation of precipitates is dependent on ion concentration in the water. Analysis of the water composition for each region and formation has been performed to identify which set of parameters increases the tendency to form scale. Solubility of inorganic salts is highly dependent on pressure and temperature changes taking place in the wellbore; therefore, the scale prediction study also includes these factors with the correlation to well region and reservoir properties each well penetrates. Weighted ranks for every parameter have been developed to rank a well after the drilling stage and make a proactive decision on whether scale inhibitor injection should be included in the primary acid stimulation treatment program, or if it should be considered only for reactive acid treatments in case of loss in well productivity. This paper aims to share the best practices in scale inhibitor design, analysis of well parameters at the well completion stage and calculation of well tendency to scale formation. The decision tree for identification of well candidates for proactive scale treatments applicable for the Tengiz field presented in the paper can potentially be used in other carbonate fields.
- Geology > Mineral > Sulfate (0.69)
- Geology > Geological Subdiscipline (0.68)
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (1.00)
- Materials > Chemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Oceania > Australia > Victoria > Bass Strait > Gippsland Basin (0.99)
- Asia > Kazakhstan > Mangystau Oblast > Precaspian Basin > Tengiz Field > Tengiz Formation (0.99)
- Asia > Kazakhstan > Mangystau Oblast > Precaspian Basin > Tengiz Field > Korolev Formation (0.99)
Evaluating the Potential of Biodegradable Carbohydrates and the Aqueous Extract of Potato Pulp to Inhibit Calcium Carbonate Scale in Petroleum Production
Ortiz, Ronald W. P. (NQTR, Instituto de Química, Universidade Federal do Rio de Janeiro (UFRJ)) | Oliveira, Jessica (NQTR, Instituto de Química, Universidade Federal do Rio de Janeiro (UFRJ)) | Vaz, Guilherme V. (NQTR, Instituto de Química, Universidade Federal do Rio de Janeiro (UFRJ)) | Passos, Nayanna Souza (NQTR, Instituto de Química, Universidade Federal do Rio de Janeiro (UFRJ)) | Bispo, Felipe J. S. (NQTR, Instituto de Química, Universidade Federal do Rio de Janeiro (UFRJ)) | Gonçalves, Vinicius Ottonio O. (NQTR, Instituto de Química, Universidade Federal do Rio de Janeiro (UFRJ)) | Cajaiba, Joao (NQTR, Instituto de Química, Universidade Federal do Rio de Janeiro (UFRJ)) | Ortiz-Bravo, Carlos A. (Departamento de Físico-química, Instituto de Química, Universidade Federal Fluminense (UFF)) | Kartnaller, Vinicius (NQTR, Instituto de Química, Universidade Federal do Rio de Janeiro (UFRJ) (Corresponding author))
Summary Scale is a significant operational concern in petroleum production that is commonly addressed by using chemical inhibitors. However, commercial inhibitors can potentially be pollutants depending on their composition and method of disposal. Consequently, evaluating the potential of biodegradable molecules to inhibit scale has gained attention. This study evaluates the effect of a series of carbohydrates (i.e., glucose, fructose, sucrose, maltose, maltodextrin, and soluble starch) and the aqueous extract of potato pulp on calcium carbonate precipitation and scale formation. Precipitation tests were conducted by combining aqueous solutions of sodium bicarbonate (3000 mg L) and calcium chloride (4000 mg L) in the presence of each carbohydrate, the aqueous extract of potato pulp, or a commercial inhibitor (1000 mg L). The precipitation was monitored through RGB (red, green, and blue) image analysis and pH measurements. The induction time in the presence of glucose, fructose, maltose, and sucrose is two to three times longer than in the blank test (in the absence of an inhibitor). This effect is slightly more pronounced in the presence of maltodextrin and soluble starch (approximately four times longer). However, the drop in pH and the mass of solids recovered is similar for all the carbohydrates tested (~0.5 mg and 120 mg, respectively), suggesting that carbohydrates slightly influence the precipitation kinetics but do not affect the precipitation equilibrium. Scanning electron microscopy (SEM) and X-ray powder diffraction (XRD) analysis reveals that calcium carbonate precipitates as calcite and vaterite in the blank test. In the presence of glucose, fructose, maltose, and maltodextrin, calcium carbonate exclusively precipitates as calcite. However, in the presence of sucrose and soluble starch, calcium carbonate precipitates as both calcite and vaterite. Interestingly, a more prominent amount of vaterite was observed in the presence of soluble starch. All carbohydrates decrease the crystallite size of calcite, while sucrose and soluble starch increase the crystallite size of vaterite. The crystalline phases were also identified by Raman spectroscopy, ruling out the presence of any amorphous calcium carbonate phase. The inhibitory effect of soluble starch and the aqueous extract of potato pulp on calcium carbonate scale formation was evaluated in a dynamic scale loop (DSL) system. Soluble starch slightly delays scale formation even at high concentrations (1000 mg L). Conversely, the aqueous extract of potato pulp demonstrates enhanced performance by delaying scale formation by approximately 20 minutes for a 1-psi increase in the pressure of the tube and by more than 40 minutes for a 4-psi increase. As a result, it exhibited an impact on the kinetics of solid deposition. This agrees with the precipitation test in the presence of the potato extract (PE), which increases the induction time (from 2 minutes to 32 minutes), decreases the mass of solids (from 116 mg to 35 mg), and forms more distorted and smaller particles of calcite. These findings suggest a promising approach for the development of green scale inhibitors utilizing aqueous extracts of starchy foods or even starchy foods waste water.
- North America > United States (0.93)
- Europe (0.93)
- South America > Brazil (0.69)
- Materials > Chemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (0.50)
Hyamine Method Applied to Brazilian Campos Basin
Rizzo, P. (SENAI Innovation Institute of Green Chemistry, Rio de Janeiro, Rio de Janeiro, Brazil) | Santos, I. (SENAI Innovation Institute of Green Chemistry, Rio de Janeiro, Rio de Janeiro, Brazil) | Brant, V. (SENAI Innovation Institute of Green Chemistry, Rio de Janeiro, Rio de Janeiro, Brazil) | de Barros, L. (SENAI Innovation Institute of Green Chemistry, Rio de Janeiro, Rio de Janeiro, Brazil) | Fidalgo Neto, A. (SENAI Innovation Institute of Green Chemistry, Rio de Janeiro, Rio de Janeiro, Brazil) | da Silva, M. (Petrobras, Rio de Janeiro, Rio de Janeiro, Brazil) | Fontes, R. (Petrobras, Rio de Janeiro, Rio de Janeiro, Brazil) | Sacorague, L. (Petrobras, Rio de Janeiro, Rio de Janeiro, Brazil) | Carvalho, R. (Petrobras, Rio de Janeiro, Rio de Janeiro, Brazil) | Freitas, T. C. (Petrobras, Rio de Janeiro, Rio de Janeiro, Brazil) | Silva, J. (Petrobras, Rio de Janeiro, Rio de Janeiro, Brazil) | Silva, G. M. (Petrobras, Rio de Janeiro, Rio de Janeiro, Brazil)
Abstract The residual level analysis related to scale inhibitors in produced water using offshore methodology is the key challenge in inorganic scale management, therefore proposal of simple and fast analytical techniques is mandatory. The objective of this work is to quantify residual polymeric scale inhibitors in produced water from a Brazilian post-salt well A using the solid-phase extraction (SPE) followed by reaction with a precipitating agent and subsequent turbidimetric evaluation. Major obstacle in this development topic regarding residual scale inhibitor detection methodologies relay on the matrix interference due to contaminants and the usual high salinity in samples. In fact, SPE allowed the removal of these interferents and, also, made feasible the analyte pre-concentration. The reagent Hyamine 1622 was employed due to its ability to effectively precipitate anionic surfactants, generating detectable turbidity. For this, the methodology was optimized considering sample percolation and desorption volumes, pH, time and temperature related to the complexation between the inhibitor and Hyamine 1622, being then successful in quantifying the polymeric scale inhibitor (usually employed in squeeze treatment) in residual levels with adequate linearity. In addition, it was found that the possible presence of iron (due to corrosive processes) does not compromise the analy sis, which is highly desirable. Further evaluation was also carried out with synthetic brine samples (representative of the field conditions), showing similar behavior that is found for produced water, indicating that the procedure is efficient in removing interferents. Each brazilian scenario offers physicochemical particularities due to the inherent well characteristics, which are based both on the matrix and the active polymeric compounds from the squeeze treatment. Therefore, each development and optimization method will depend on these variables, but the present initiative demonstrates not only the viability of the analytical and operational approach, but also the potential to standardize analyzes in an offshore environment.
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (1.00)
- Energy > Oil & Gas > Upstream (1.00)
Systematic Modelling and Laboratory Testing to Allow the Potential for Economic Inorganic Scale Control in the Brazilian Pre-Salt Fields
Littlehales, Ian (Scaled Solutions USA) | Simões Neto, Saul (Petrobras) | Dias Neto, Jose Mateus (Petrobras) | Lee, Ji-young (Shell International Exploration and Production Inc.) | Ko, Saebom (Brown & Root Industrial Services) | Mendes, Marcello (Shell Brasil Petroleo Ltda.) | Graham, Gordon (Scaled Solutions Ltd) | Dyer, Sarah (Scaled Solutions Ltd) | Peat, Stephnie (Scaled Solutions USA)
Abstract Pre-salt oil fields such as those produced in the Offshore market in Brazil, offer a unique set of challenges related to the control of inorganic scale deposits. Scale deposition has the potential to negatively impact production rates and profitability of the operations. Often laboratory testing studies examine the performance of scale inhibitors using so called industry standard techniques like the Dynamic Scale Loop (DSL) but can sometimes be conducted under unrealistic scaling conditions considered by the operators or laboratory scientist to be "worst case". This however can severely limit the number of products that can be successfully qualified for application in the field and lead to recommendations of very high dose rates, which may not be achievable as water cuts increase. To successfully test chemicals in the laboratory prior to field application, the conditions of the tests must closely represent the field. This includes the brine chemistry of the well, the CO2 concentration and pH of the fluids. This paper will detail the results of a new modelling and laboratory study which shows an extremely severe scaling regime that could be expected under the pre-assigned worst case field conditions leading to the failure of chemicals to economically prevent scale. However, when all parameters are considered, laboratory conditions were optimized to represent field conditions more closely, resulting in a more representative (milder) in-situ scaling regime such that chemical performance was significantly improved. Ultimately when the laboratory conditions were tuned to the newly modelled in-situ field conditions, there was a significant reduction in the minimum effective dose (MED) determined in the lab for all conditions, offering the potential for effective treatments to be achieved even at increased water cuts. This work shows that only focusing on one system parameter like maximum field pH results in an overly severe testing regime, limiting the number of products available to the Operating Company. The "worst case" approach also results in the dose rates of those chemicals which are selected being unrealistically high for field application at high water cuts. When more representative in-situ conditions are modelled and then utilised in the laboratory, a wide range of scale inhibitor chemistries would potentially be available for field applications allowing the operator to realize significant OPEX savings. The paper also highlights how careful modelling and optimisation of test conditions is a critical aspect associated with scale inhibitor qualification and highlights the best practice approach to selecting and optimising test conditions in the laboratory to ensure they remain representative of the field conditions.
- South America > Brazil (1.00)
- North America > United States > Louisiana (0.70)
- North America > United States > Texas (0.46)
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (1.00)
- Energy > Oil & Gas > Upstream (1.00)
Mechanistic Analysis of Various Scale Inhibitors on Calcium Sulfate Precipitation
Alissa, F. M. (Saudi Aramco PE&D, Dhahran, Saudi Arabia) | Aljeaban, N. A. (Saudi Aramco PE&D, Dhahran, Saudi Arabia) | Tobon-Gonzalez, J. (Water Desalination and Reuse Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia) | Albaiz, A. I. (Saudi Aramco NAOO, Ras Tanura, Saudi Arabia) | Alzahrani, A. A. (Saudi Aramco PE&D, Dhahran, Saudi Arabia)
Abstract The deposition of scales is one of the major challenges in the oil and gas industry. Prevention of such challenge is carried out using chemicals known as scale inhibitors. However, not all inhibitors function the same. For instance, some inhibitors function as threshold inhibitors, while others function as crystal modifiers. In order to investigate this, several experiments for precipitating Calcium Sulfate were carried out in the laboratory by mixing Calcium, and Sulfate brines. Following the precipitation process, the solid was filtered out using vacuum filtration. Subsequently, ion chromatography was used to determine the concentration of sulfate ions present in the solution. Herein, the inhibition efficiency of various phosphonic-acid based inhibitors: ATMP, PAPEMP, and BHMTMP were examined and compared against a baseline blank test. Afterward, the mechanism of inhibition was interpreted from the kinetic experiments. Generally, the performance of a threshold inhibitor tends to plateau. Both ATMP and BHMTMP reached a maximum inhibition efficiency of calcium sulfate precipitation around 30%. No significant change was noticed when increasing the concentrations to 300 ppm. On the other hand, the performance of PAPEMP was non-threshold reaching 53% inhibition efficiency at the same concentration.
- Asia > Middle East > Saudi Arabia (0.70)
- North America > United States (0.68)
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (0.92)
- Water & Waste Management > Water Management > Water & Sanitation Products (0.66)
- Materials > Chemicals > Specialty Chemicals (0.66)
Integrated Approach Combining Plant Data and Thermodynamic Simulation for Management of Inorganic Scale in Topsides Processing Facilities
Neto, S. Simoes (Petrobras, Santos, Sao Paulo, Brazil) | Smiderle, A. L. (Petrobras, Santos, Sao Paulo, Brazil) | Neto, J. M. Dias (Petrobras, Santos, Sao Paulo, Brazil) | Alves, A. F. (Petrobras, Santos, Sao Paulo, Brazil)
Abstract A major concern with pre-salt processing is the water salinity and its high scaling potential. High standing output levels necessitate an effective scaling management strategy. One element of a successful program is scale prediction, which is frequently done utilizing the produced water's thermodynamic equilibrium. This paper presents a methodology and algorithm to systematically calculate scaling index of produced water blend to be compared to representative brines which were defined for scaling inhibitor design tests. Thermodynamic calculations of calcite saturation indexes at relevant process conditions are evaluated for the mixture of produced wells streams and for the platform critical brine. It was implemented an algorithm that integrates plant historian database to thermodynamic calculation routines and presents the results in a user-friendly web portal for proper visualization. Calcite saturation index is calculated using Pitzer activity model which is often used for calculations of inorganic scaling potential in high ionic waters. Produced wells flowrates are used for defining mixture fractions of the produced blend. For each platform there is one representative brine composition that was used for scale inhibitor design, herein called the platform critical brine. However, the compositions of wells produced water are updated as soon as new water analysis is available. The algorithm creates a scaling index (ISS) based on calcite saturation indexes that measures how far from the critical brine the produced mixture is in relation to calcite saturation index. The ISS is evaluated systematically in daily basis for several platforms offshore Brazil. The results show how the different wells configurations (flowrates) impact the produced water blend criticality with respect to inorganic scaling. The implemented routine gives insight to production engineering personnel regarding potential problems with scaling and chemicals design. It can be used to assess if the platform critical brine should be updated, and possibly new chemicals designed. Additionally, the ISS can be used to optimize the topsides process conditions in specific scenarios. The processing conditions and produced water compositions of pre-salt oilfields offshore Brazil results in scaling potential at topsides. This paper describes the methodology applied for monitoring the scaling potential systematically on a daily basis for several pre-salt platforms.
- South America > Brazil (1.00)
- North America > United States > Louisiana (0.24)
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (0.74)
Summary Offshore oil and gas production is known to present severe flow assurance issues, in particular calcium carbonate (CaCO3) scale deposition, as its formation reaction is influenced by temperature and pH changes that occur during production. This study investigated the calcium carbonate scaling process using a newly developed 1-inch diameter mesoscale loop and also the efficiency of sodium hexametaphosphate (SHMP) as a scale inhibitor for calcium carbonate under drastic conditions of temperature, flow rate, and scaling ions concentration. The relationship between flow rate, temperature, experimental time, and CaCO3 formation parameters was evaluated using a dynamic methodology designed for the mesoscale loop. Moreover, scanning electron microscopy (SEM) images and energy-dispersive spectrum (EDS) chemical analysis were used to study changes in the microstructure and the elemental composition of the deposits in the absence and presence of the scale inhibitor. The inhibition effect was found satisfactory, as CaCO3 deposition greatly decreased. The deformed structures of the CaCO3 crystals observed by SEM images and EDS analysis helped visualize the changes due to the SHMP. Finally, the temperature changes due to the accumulation of deposits through thermal images were helpful in explaining what was happening inside the pipes system during the scaling tests.
- Europe (0.46)
- South America > Brazil (0.28)
- North America > United States (0.28)
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (1.00)
- Materials > Chemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
Abstract Scale inhibitor squeeze (SISQ) treatment is an established method for offshore fields which allows an extended effectiveness of the scale inhibitors in preventing scale deposition over time. Some of the main issues in SISQ campaign is the short squeeze lifetime being less than 1 year which may be contributed by operational and well integrity issues as well as ineffective design of the pre-flush system. This study proposed graphene nanoplatelets as pre-flush system to extend the lifetime of a conventional scale inhibitor squeeze treatment. This carbon-based nanomaterial known for its high specific surface area provided an excellent pre-coating on the rock matrix, allowing an enhanced adsorption of the phosphonate-based scale inhibitor. Special attention was given to the study on stability of the graphene nanoplatelets (GNP) in high divalent injection water and its functionalization with biopolymer to provide good dispersibility in the seawater at high temperature condition. This paper focuses on the compatibility evaluations of GNP in seawater, its dispersion and thermal stability assessment up to 96oC temperature, followed by an innovative static adsorption experiment using Berea crushed cores which served to establish the improvement in scale inhibitor adsorption at different GNP concentrations. For in-depth performance evaluations in downhole porous media, injectivity and adsorption-desorption scale squeeze treatment coreflooding experiments using Berea and reservoir native cores at high temperature conditions were then tmperformed. Finally, prediction on the field squeeze lifetime were simulated using Place-iT™ software. Results shown that the scale inhibitor's adsorption increased by more than 100% when 200 ppm of modified GNP was used as pre-flush compared to conventional pre-flush system. Good injectivity profiles, showing Residual Resistance Factor (RRF) of less than 3, coupled with slower desorption rate of scale inhibitor were observed from the coreflooding results. The simulated scale squeeze lifetime improved up to additional 14 months compared to baseline. Graphene nanoplatelets have demonstrated its versatility as nanocoating agent in enhancing scale inhibitor squeeze lifetime, extending its application as downhole high temperature production enhancement chemical.
- North America > United States (0.68)
- Asia > Malaysia (0.47)
- Research Report > New Finding (0.48)
- Research Report > Experimental Study (0.48)
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (1.00)
- Materials (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Asia > Middle East > UAE > Abu Dhabi > Arabian Gulf > Rub' al Khali Basin > Abu Dhabi Field (0.99)
- Asia > Malaysia > South China Sea > Malay Basin (0.99)
Holistic Approach of Inorganic Scale Inhibition Application in Extending Well Production Life
Mat Deris, Nurul Asyikin Binti (Hibiscus Oil & Gas Malaysia Limited) | Siew, Caleb Jia Lih (Hibiscus Oil & Gas Malaysia Limited) | Khoo, Alan (Hibiscus Oil & Gas Malaysia Limited) | Abd Rahim, Mohd Adam Bin (Hibiscus Oil & Gas Malaysia Limited) | Arief Saleh, Fakhrul Amin Bin (Hibiscus Oil & Gas Malaysia Limited) | Amsidom, Amirul Adha Bin (PETRONAS)
Abstract Flow assurance problems such as inorganic scale formation in gas lifted wells have been common in field production lifecycle and presence of higher water production accelerates this occurrence. Production impairment is the consequence of scale formation that can be eliminated by preventive measures in scale management. The most effective technique for mitigating downhole scale formation is through the application of scale inhibitor solution injected into the near wellbore of the formation. Chemical selection is crucial to ensure effectiveness and longevity of the treatment for it not only to be technically proven but also economically viable. Through rigorous laboratory testing and field trials, scale inhibitor squeeze (SISQ) has been the proven solution to effectively increase the productivity and uptime in most of the gas lifted wells in Hibiscus Oil & Gas Malaysia Limited assets. The SISQ injection dosage and duration were designed based on well production and reservoir properties, and it is injected into the wellbore via the bull heading technique. The treatment has become a routine activity and well candidates are identified through scale mapping exercise. This paper presents the journey of SISQ implementation in Hibiscus Malaysia Limited's operating fields which includes the history of actual SISQ monitoring trends and the frequency of SISQ being optimized. The cost saving and well uptime will also be discussed in this paper.
- Asia > Malaysia (0.72)
- Europe > Norway > Norwegian Sea (0.24)
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Asia > Vietnam > Gulf of Thailand > Malay Basin > Malay-Tho Chu Basin > Block PM 3 CAA > Bunga Kekwa Field (0.98)
- Asia > Malaysia > Gulf of Thailand > Malay Basin > Malay-Tho Chu Basin > Block PM 3 CAA > Bunga Kekwa Field (0.98)
Evaluation of Polyamidoamine-Assisted Scale Inhibitors to Mitigate Silicate Scale Formation in Near Wellbore Region
Tan, Bee Chea (Universiti Teknologi PETRONAS) | Saaid, Ismail Mohd (Universiti Teknologi PETRONAS) | Mahat, Siti Qurratu'Aini (Universiti Malaysia Pahang) | Zainal, Suzalina (PETRONAS Research Sdn Bhd) | Bhaskoro, Petrus Tri (PETRONAS Research Sdn Bhd) | Anuar, Astriyana (Petroliam Nasional Berhad)
Abstract Silicate scaling is a concern that could result in formation damage and flow assurance issue. Phosphonates and phosphino-polyacrylates are widely used to treat many types of scale but they are not intended to treat silicate scale. Besides that, these inhibitors may have been considered as harmful substances due to their reported inherent biodegradability. Synergistic silicate scale inhibitors are current trends since cationic or anionic polymers alone is found not effective for silicate scale inhibition. The objective of this work is to assess the performance of polyamidoamine-assisted scale inhibitors for silicates. The experiment settings are simulating the environment in near wellbore region, such that higher temperatures and brine that is mostly pH neutral. The effectiveness of scale inhibitors is investigated through static bottle test and dynamic scale loop (DSL) test. The scale inhibitors are also characterized to determine their functional groups in aqueous state. The tendency of scale inhibitors to impede silicate polymerization process is also determined through the remaining concentration of monomeric silica in water after 72 hours. FTIR revealed that all scale inhibitors exhibit amine characteristic in water. Experimental results show that the polyamidoamine-assisted scale inhibitor, PAMAM G-2/PteGlu, is the most effective in mitigating silicate scale formation. It reduces scaling brine's turbidity as much as 94.8% after 72 hours at 90°C. In addition, it also minimizes silicate polymerization process by retaining almost half of the initial monomeric silica concentration. This also implies that PAMAM G-2/PteGlu inhibitor could reduce the tendency of silicate scale formation to 46% as compared to 97% of silicate scale formation without any inhibition at 95°C. From DSL test, PAMAM G-2/PteGlu inhibitor is also the most effective inhibitor. It prolongs the scaling time from 7 minutes to 339 minutes at 0.01 g/L inhibitor concentration. It is also 7% more effective than PAMAM G-1/PteGlu inhibitor in DSL test. In general, the performance of scale inhibitors for silicates can be arranged as: PAMAM G-2/PteGlu > PAMAM G-1/PteGlu > PteGlu > PAMAM G-2 > PAMAM G-1 from top to bottom. In this work, these environment-friendly products had demonstrated good silicate scale inhibition as well as synergistic effect. They could offer as alternatives to commercial scale inhibitors.
- Water & Waste Management > Water Management > Water & Sanitation Products (1.00)
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (1.00)
- Materials > Chemicals > Specialty Chemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)