Electrochemical treatment process of polymer fracturing flowback fluid in oilfield

doi:10.19965/j.cnki.iwt.2021-1242

Abstract

Abstract:

Fracturing technology has gradually become the main mean of oilfield stimulation. As more stricter Emission Standard of Pollutants for Onshore Oil and Gas Exploitation and Production Industry is to be issued，the Mahu oilfield in Xinjiang is likely to face the pressure of polymer fracturing flowback fluid efflux in the next few years. Based on the requirements of high efficiency and low cost，a process combined of electric flocculation pretreatment and electrochemical oxidation was developed to treat fracturing flowback fluid. The results showed that with the electrocoagulation pretreatment condition of the anode and cathode plates both aluminum plates，the distance between the plates 0.5 cm，the current density 10 mA/cm²，and the electrification time 15 min，the COD removal rate of fracturing flowback fluid reached 65.4% and turbidity reached 4 NTU. The fracturing flowback fluid after electrocoagulation pretreatment was treated by electrochemical oxidation. Under the conditions of ruthenium-iridium plated titanium plate as anode，stainless steel plate as cathode，current density of 25 mA/cm²，pulse frequency of 4 000 Hz，duty cycle of 65%，pH=7.2，and reaction time of 90 min，COD of fracturing flowback fluid of Xinjiang Mahu oilfield could be reduced to less than 80 mg/L，oil mass concentration to less than 1.0 mg/L，ammonia nitrogen to less than 0.5 mg/L，suspended matter to less than 30 mg/L. The water quality index of the treated fracturing flowback fluid met the requirements of the onshore discharge standard and the cost was low，which had an excellent industrial application prospect.

Key words: fracturing flowback fluid, electric flocculation, electrochemical oxidation, pulse power, emission standard

摘要：

压裂技术已逐渐成为油田增产的主要手段。随着更加严格的《陆上石油天然气开采工业污染物排放标准》的即将颁布，新疆玛湖油田在未来几年可能会面临大量聚合物型压裂返排液外排的压力。基于高效、低成本的处理要求，开发了“电絮凝预处理+电化学氧化”工艺处理压裂返排液。结果表明：当电絮凝预处理条件为阴阳极板均为铝板、极板间距为0.5 cm、电流密度为10 mA/cm²、通电时间为15 min时，压裂返排液COD去除率达到65.4%，浊度达到4 NTU。对电絮凝预处理后的压裂返排液进行电化学氧化处理，在阳极为镀钌铱钛板、阴极为不锈钢板、电流密度为25 mA/cm²、电源脉冲频率为4 000 Hz、占空比为65%、pH=7.2、反应时间为90 min的条件下，新疆玛湖油田压裂返排液COD可以降至80 mg/L以下，油质量浓度降至1.0 mg/L以下，氨氮降至0.5 mg/L以下，悬浮物降至30 mg/L以下。处理后压裂返排液水质指标满足陆上排放标准要求且成本较低，具有良好的工业应用前景。

关键词: 压裂返排液, 电絮凝, 电化学氧化, 脉冲电源, 排放标准

CLC Number:

X703.1

Yuxin FAN, Haibing ZHANG, Weiqiang HUANG, Yuanyuan HU, Qing WANG, Xiurong LÜ. Electrochemical treatment process of polymer fracturing flowback fluid in oilfield[J]. Industrial Water Treatment, 2022, 42(10): 139-145.

樊玉新, 张海兵, 黄伟强, 胡远远, 王青, 吕秀荣. 电化学工艺处理油田聚合物型压裂返排液[J]. 工业水处理, 2022, 42(10): 139-145.

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URL: https://gyscl.magtechjournal.com/EN/10.19965/j.cnki.iwt.2021-1242

https://gyscl.magtechjournal.com/EN/Y2022/V42/I10/139

Figures/Tables 13

Table 1 Comparison of main indicators of sewage discharge standards

标准	COD/（mg·L^-1）	石油类/（mg·L^-1）	悬浮物/（mg·L^-1）	氨氮/（mg·L^-1）
陆上标准	100	8	70	8
GB 8978—1996	150	10	150	50

Table 2 Properties of polyacrylamide type fracturing flowback fluid in Mahu oilfield

项目	数值
pH	7.18~7.29
浊度/NTU	76.6~83.70
COD/（mg·L^-1）	985~1 180
电导率/（mS·cm^-1）	20.33~22.70
TDS/（g·L^-1）	8.97~9.27
油/（mg·L^-1）	15.57~16.22
悬浮物/（mg·L^-1）	310.7~335.70
氨氮/（mg·L^-1）	2.82~3.60
运动黏度/（mPa·s）	3.25~3.30

Fig. 1 Pretreatment effect of PAC and PFC dosage on COD

Fig. 2 Relationship of PAM dosage and treatment effect

Fig. 3 Relationship of pretreatment effect of electric flocculation and time

Table 3 Cost comparison between electric flocculation and reagent flocculation

药剂絮凝成本/（元·t^-1）				电絮凝成本/（元·t^-1）
PFC	PAC	PAM		电费	铝板	PAM
0.24	0.28	0.12		0.2	0.2	0.12

Fig. 4 Influence of plates spacing on COD removal

Fig. 5 Influence of current density on COD removal

Fig. 6 Influence of different pH on COD removal

Fig. 7 Influence of pulse frequency on COD removal

Fig. 8 Influence of different duty ratio on COD removal

Table 4 Variation of index parameters under optimum conditions

项目	COD/（mg·L^-1）	油/（mg·L^-1）	氨氮/（mg·L^-1）	悬浮物/（mg·L^-1）
预处理前	1 010.0	14.6	3.5	324.5
预处理后	401.8	8.5	3.1	60.6
电化学氧化后	78.4	0.8	0.3	26.7

Table 5 Cost of electrochemical treatment of polymer fracturing flowback fluid

预处理成本/（元·t^-1）	电化学氧化成本/（元·t^-1）
预处理成本/（元·t^-1）	电费	极板材料费	人工费和折旧费
0.52	15	18.75	5~10

References 10

1	徐延涛，郭布民，陈玲，等. 海上压裂返排液高效环保处理技术［J］. 石油地质与工程，2021，35（4）：106-109. doi:10.3969/j.issn.1673-8217.2021.04.022
	LIU Yantao， GUO Bumin， CHEN Ling，et al. High efficiency and environmental protection treatment technology for offshore fracturing flow-back fluid［J］. Petroleum Geology and Engineering，2021，35（4）：106-109. doi:10.3969/j.issn.1673-8217.2021.04.022
2	彭杰，田永刚，马军军，等. 含压裂返排液采出水处理工艺优化［J］. 工业水处理，2022，42（5）：157-162.
	PENG Jie， TIAN Yonggang， MA Junjun，et al. Optimization of produced water containing fracturing flowback fluid treatment process［J］. Industrial Water Treatment，2022，42（5）：157-162.
3	ZHUO Qiongfang， XIANG Qian， YI Hao，et al. Electrochemical oxidation of PFOA in aqueous solution using highly hydrophobic modified PbO₂ electrodes［J］. Journal of Electroanalytical Chemistry，2017，801：235-243. doi:10.1016/j.jelechem.2017.07.018
4	MOHAMADIGHADER N， NEMATOLLAHI D， SARAEI M. A comprehensive study on electrochemical oxidation of phenothiazine in water-acetonitrile mixture：Electrosynthesis of phenothiazine dimers［J］. Electrochimica Acta，2022，425：140706. doi:10.1016/j.electacta.2022.140706
5	FERREIRA M， PINTO M F， NEVES I C，et al. Electrochemical oxidation of aniline at mono and bimetallic electrocatalysts supported on carbon nanotubes［J］. Chemical Engineering Journal，2015，260：309-315. doi:10.1016/j.cej.2014.08.005
6	LI Xiaoliang， XU Hao， YAN Wei，et al. Electrocatalytic degradation of aniline by Ti/Sb-SnO₂，Ti/Sb-SnO₂/Pb₃O₄ and Ti/Sb-SnO₂/PbO₂ anodes in different electrolytes［J］. Journal of Electroanalytical Chemistry，2016，775：43-51. doi:10.1016/j.jelechem.2016.05.033
7	PALMA-GOYES R E， GUZMÁN-DUQUE F L， PEÑUELA G，et al. Electrochemical degradation of crystal violet with BDD electrodes：Effect of electrochemical parameters and identification of organic by-products［J］. Chemosphere，2010，81（1）：26-32. doi:10.1016/j.chemosphere.2010.07.020
8	DEBORDE M， VON GUNTEN U. Reactions of chlorine with inorganic and organic compounds during water treatment—Kinetics and mechanisms：A critical review［J］. Water Research，2008，42（1/2）：13-51. doi:10.1016/j.watres.2007.07.025
9	LEI Jiani， XU Zhicheng， XU Hao，et al. Pulsed electrochemical oxidation of acid Red G and crystal violet by PbO₂ anode［J］. Journal of Environmental Chemical Engineering，2020，8（3）：103773. doi:10.1016/j.jece.2020.103773
10	范涛. 某页岩气井压裂返排液处理工程实例［J］. 广东化工，2022，7（49）：153-155. doi:10.3969/j.issn.1007-1865.2022.07.053
	FAN Tao. An engineering application of shale gas well fracturing flowback fluid treatment［J］. Guangdong Chemical Industry，2022，7（49）：153-155. doi:10.3969/j.issn.1007-1865.2022.07.053

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