Materials Performance

MAR 2017

Materials Performance is the world's most widely circulated magazine dedicated to corrosion prevention and control. MP provides information about the latest corrosion control technologies and practical applications for every industry and environment.

Issue link: http://mp.epubxp.com/i/792600

Contents of this Issue

Navigation

Page 50 of 80

48 MARCH 2017 MATERIALS PERFORMANCE NACE INTERNATIONAL: VOL. 56, NO. 3 CHEMICAL TREATMENT C The influence of enhanced oil recov- ery chemicals on the performance of calcium carbonate (CaCO 3 ) scale in- hibitors has shown that the surfactant and polymer reactions can result in a significant decrease in scale inhibitor efficacy, as well as substantial varia- tions in CaCO 3 morphology. These effects must be considered in scale management for these projects. Calcium carbonate (CaCO 3 ) scale has long been a challenge in the oil and gas industry. In addition to inducing localized corrosion, scale deposits can cause f low restrictions in reser v oir ro ck s, tubing string, and sur face pip e w ork; d amage production and safety devices; and upset oil/water separation. CaCO 3 formation is usually related to changes in physical conditions, such as temperature and pressure. 1-2 CaCO 3 scaling tendency and precipitation kinetics in- crease with temperature. As pressure de- creases, dissolved carbon dioxide (CO 2 ) gas evolves from the water phase, which raises the pH level . Thus, the thermodynamic driving force for CaCO 3 precipitation is initiated. The CaCO 3 scaling problem can be ex- acerbated in enhanced oil recovery (EOR) operations. 3-4 In thermal EOR, the increase in temperature from the added heat and the related change in water composition due to dissolution of reservoir rocks can aggravate scale formation. 5 In CO 2 EOR , the injected CO 2 , once mixed with water in the reservoir, is able to dissolve large quan- tities of calcareous rock and the produced water becomes enriched with scaling cal- cium and carbonate ions. 6 In chemical EOR, the CaCO 3 scaling risk is elevated sig- nificantly when the alkali agents such as sodium hydroxide (NaOH) and sodium car- bonate (Na 2 CO 3 ) are used. 7 Many studies have been conducted to investigate the impact of increased pH on scale formation and prevention. 8-9 Little attention, how- ever, has been paid to the possible interfer- ence of the EOR polymer and surfactant on scale inhibitor performance. This study reports the laboratory results on the im- pact of EOR chemicals on the kinetics, m o r p h o l o g y, a n d p o ly m o r p h o l o g y o f CaCO 3 precipitation and inhibition. Experimental Procedures Reagent-grade chemicals and double- deionized water were used to prepare the stock solutions. The test water contained 828.2 mM of sodium, 18.0 mM of potas- sium, 98.4 mM of calcium, 52.9 mM of mag- nesium, 0.7 mM of strontium, 8.2 mM of bi carb on at e , 1 9 . 2 m M of sul fat e , an d 1,103.4 mM of chloride. Cation and anion solutions were prepared separately, and mixing equal volumes of cation and anion solutions provided the desired water com- Calcium Carbonate Scale Formation and Inhibition During Enhanced Oil Recovery Qiwei w ang, Hameed a l-Badairy, S H ouwen S H en, and w aleed a l- n a SS er, Research & Development Center, Saudi Aramco, Dhahran, Saudi Arabia

Articles in this issue

Archives of this issue

view archives of Materials Performance - MAR 2017