scholarly journals Co-Deposition Mechanisms of Calcium Sulfate and Calcium Carbonate Scale in Produced Water

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1494
Author(s):  
Yan Yan ◽  
Tao Yu ◽  
Huan Zhang ◽  
Jiayu Song ◽  
Chengtun Qu ◽  
...  

Co-precipitation of mineral-based salts during scaling remains poorly understood and thermodynamically undefined within the water industry. This study focuses on investigating calcium carbonate and calcium sulfate mixed precipitation in scaling. Scaling is often observed in the produced water supply as a result of treatment processes. Co-precipitation results were compared with experimental results of a single salt crystallization. Several parameters were carefully monitored, including the electrical conductivity, pH value, crystal morphology and crystal form. The existence of the calcium carbonate scale in the mixed system encourages the loose calcium sulfate scale to become more tightly packed. The mixed scale was firmly adhered to the beaker, and the adhesion of the co-deposition product was located between the pure calcium sulfate scale and the pure calcium carbonate scale. The crystalline form of calcium sulfate was gypsum in both pure material deposition and mixed deposition, while the calcium carbonate scale was stable in calcite form in the pure material deposition. In the co-deposition, apart from calcite form, some calcium carbonate scale crystals had metastable vaterite form. This indicated that the presence of SO42− ions reduced the energy barrier of the calcium carbonate scale and hindered its transformation from a vaterite form to a calcite one, and the increase in HCO3− content inhibited the formation of calcium sulfate scale.

Author(s):  
A. Saifelnasr ◽  
M. Bakheit ◽  
K. Kamal ◽  
A. Lila

In this study the predictions and probabilities of calcium carbonate scale formation and corrosion occurrence inside Gumry Field Process Facilities (GFPF) and produced water injection process units (PWTP) was carried out. This was done calculating the Langelier Saturation Index (LSI), Ryznar Stability Index (RSI), Puckorius Scaling Index (PSI). The samples results for LSI index and PSI index were compared and found that all samples under threaten of calcium carbonate scale. The samples results for RSI index and found that all samples under formation of heavy calcium carbonate scale. Special excel computer program was designed to calculate the (LSI, RSI, PSI). The scale was cleaned and removed by 10% diluted hydrochloric acid and commercial scale inhibitor.


2014 ◽  
Author(s):  
Nan Zhang ◽  
Amy T. Kan ◽  
Mason B. Tomson

Abstract One of the most intractable concerns when engineers try to reuse the produced water as frac fluid in the Bakken and some other shale plays is the scale formation caused by the incompatibility of produced water with additives in the frac fluids and with the formation. In order to obtain a more efficient scale treatment for a successful hydraulic fracing that handles the extraordinary amount of water with high supersaturation level, the better understanding of inhibitor retention and release in the production system is urgent. To explore the mechanism of attachment/release of phosphonate to/from a mineral surface, calcite supersaturated feed solutions with different diethylenetriamine penta (DTPMP) concentrations were introduced into the steel tubing that was internally pre-coated with a thin layer of CaCO3. It is unveiled that DTPMP attachment was dominated by the precipitation of calcium phosphonate solid once the solution is supersaturated with Ca3H4DTPMP (pKsp=53.5), and the total amount of DTPMP attached on the calcite surface added up with the increasing supersaturation of Ca3H4DTPMP. The co-precipitation of CaCO3 and Ca3H4DTPMP has facilitated the attachment of the inhibitor with the increase of supersaturation of CaCO3. The retained phosphonate was released from the surface with a steady and low level inhibitor concentration over extended period of time. Combining with the kinetics of calcium carbonate precipitation in the presence of inhibitor, a 1500 gram of calcium phosphonate precipitation can protect the scaling for about 100 days (100 bbl/day) when the saturation index of calcium carbonate (SIcalcite) is as high as 1.3. The results provide a better understanding of calcium-phosphonate-carbonate interaction, and show the phosphonate inhibitor can continuously accumulate on the carbonate and slowly dissolve. We anticipate this study can shed a light on how much inhibitor can be delivered to the unconventional reservoir as well as the theoretical limitation of inhibitor return in the flowback water.


CORROSION ◽  
1961 ◽  
Vol 17 (5) ◽  
pp. 232t-236t ◽  
Author(s):  
L. W. JONES

Abstract The expense attributable to scaling in oil producing operations totals many millions of dollars annually. Causes of precipitation and deposition are fairly well understood but better methods of control are needed. In order to evaluate chemical scale inhibitor components, a laboratory testing device was designed. Performance of sequestrants, surface active agents, colloids, and mixed compounds in the laboratory tester are discussed. Polyphosphates and sodium carboxymethyl cellulose proved effective for calcium carbonate scale and calcium sulfate scale, respectively. Results of tests made over a period of several years led to the development of an inhibitor composition that is capable of inhibiting both carbonate and sulfate scales. The inhibitor is now in field use. 5.8.2, 3.2.3, 8.4.3


2010 ◽  
Vol 96 ◽  
pp. 35-40 ◽  
Author(s):  
Yan Ding ◽  
Jun Ping Meng ◽  
Xu Hong Zhang ◽  
Li Juan Wang ◽  
Qing Guo Tang

Multiple copper-zinc alloy was used to treat water in order to restrict the formation of hard scale during heating process. Trace amounts of metal ions were dissolved from the alloy under the action of tiny battery corrosion, which took part in the crystallization of calcium carbonate crystal. The ion migration rules and its effect on the crystal structure of water scale were studied. The ICP test results show that after immersion in the water for 20 min, the zinc ion concentration increased to 0.35 mg•L-1 compared with contrast group. The simulating experiment of the scale crystal growth demonstrated that the calcium carbonate scale after treated with the alloy showed a transformation from calcite to aragonite, and the ratio of calcite to aragonite changed from 1:0.125 to 1:2.30. Meanwhile, the heat transfer efficiency was increased to 2.19%.


Heliyon ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. e03506
Author(s):  
K. Palanisamy ◽  
K. Sanjiv Raj ◽  
S. Bhuvaneswari ◽  
M. Rajasekaran ◽  
V.K. Subramanian

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