页岩气藏压裂返排液回收处理技术探讨

页岩气藏采用大规模、大液量加砂压裂改造后返排液的处理一直是业界备受关注的热点问题,涉及到页岩气藏开发成本与环境保护两个方面。文章就页岩气压裂返排液的回收处理技术展进行了探讨,针对钻磨桥塞以及返排期间,压裂返排液中往往含有大量压裂砂等固相颗粒,分离处理难度大等难题,优化了压裂返排液回收再利用系统,主要包括捕屑模块、除砂模块和精细化过滤模块,通过捕屑模块、除砂模块实现了返排流体的初步"清洁",进一步通过精细化过滤模块对返排液中极细固体杂质进行二次精细化连续过滤,过滤精度达到10 um级别,充分提高回收液的清洁度,使得处理后的液体可直接用作下一层或下一口井压裂基液,返排液回收利用率达到90%以上。该回收再利用系统是压裂返排液深度环保处理必不缺少的组成部分,通过进一步对蒸发技术、膜处理技术、电絮凝技术等各种环保处理技术适用性进行探讨,为国内压裂返排液环保处理技术的创新发展提供借鉴,有利于进一步解决页岩气藏开发过程中水资源瓶颈和环境保护问题。     

苏里格气田压裂液循环利用技术研究与应用

过去气田使用的压裂液都是一次性压裂返排,返排液中稠化剂大分子链已深度降解,不能重复利用,这些压裂返排液的大量排放已成为不容忽视的污染源。为此,通过研发可回收压裂液体系、配套返排液处理标准和建立现场回收处理流程等技术手段,初步形成了适合苏里格气田特点的压裂液循环利用和处理方法:(1)针对井间压裂液回收再利用,形成了以EM50/50S、生物胶可回收压裂液体系为核心的高效井间压裂返排液循环再利用技术,解决了常规胍胶压裂液体系处理效率低的难题;(2)针对井场末端液体回收处理,形成了以"混凝沉淀+过滤杀菌+污泥脱水"为主体的压裂返排液精细回收处理技术。压裂液循环利用促进了节能减排工艺技术的进步。     

姬塬油田压裂返排液配制调剖剂的探索研究

随着长庆油田开发的不断深入,姬塬油田每年的压裂工作量不断增加,大量的压裂返排液无法直接排放,且处理费用高,给油田开发和环境保护都造成巨大压力。因此,综合考虑压裂返排液的环境保护、处理成本、回收再利用的要求,本文通过国内外调研、室内分析以及姬塬油田储层适应性评价,对压裂返排液用于调剖堵水进行了可行性研究,初步建立了基于压裂返排液的调剖剂配方,并进行了性能评价,形成适合于姬塬油田自身的返排液回收再利用的研究方向和思路。     

致密及页岩气藏气井分段压裂返排优化模型与分析

致密及页岩气藏气井压裂后的返排质量好坏极大地影响最终的压裂效果,目前此方面的建模未考虑到返排时的井筒内气液两相流和分段压裂多段同时返排的特点。该文对致密及页岩气井的分段压裂裂缝闭合前后的返排特点进行了分析,建立了气井压裂返排、裂缝体积变化和滤失量耦合模型,进行了实例计算分析,讨论明确了裂缝闭合前分段压裂多段同时返排优化方法,并对返排率的计算和基于储层伤害的分段压裂返排优化进行了分析。研究发现：对气井,有地层气体进入返排液时,返排的时间将增长,且在返排后期排液量增幅变小,累积返排液量较大;裂缝闭合前分段压裂多段同时返排优化时,返排量、多条裂缝体积变化和多条裂缝滤失是通过最后一条裂缝出口处的压力耦合起来的;裂缝闭合前后的返排模型的衔接,主要明确了初始井底流压为裂缝闭合前的终态井底流压,初始含水为裂缝闭合前滤失进储层的返排液;将致密及页岩气储层的水锁以及在压裂返排时的水锁自解除现象和机理,与气井压裂返排过程和分段压裂水平气井返排优化结合,以进行致密及页岩气井返排伤害的模拟,但具体实现还待进一步研究。.     

压裂返排液处理技术的研究进展

介绍了压裂返排液的性质及其处理技术,归纳了各处理技术的特点及处理效率。压裂返排液的成分复杂,处理难度大,一种方法对压裂返排液进行处理很难达到国家对返排液排放的要求,必须将几种方法联合起来对返排液进行处理。研究新型高效环保的压裂液体系和环保的生物处理剂,开发可使压裂返排液循环使用的工艺,利用油气田开发伴随的能量处理压裂返排液是将来压裂返排液处理技术发展的方向。     

凝析气藏压裂返排参数对气井产能的影响

为了确定低渗透凝析气藏压裂后的最佳返排速率，首先建立压裂返排物理模型，然后通过保角变换，将压裂后形成的椭圆形流动区域转化为圆形流动区域，利用平面径向流产能公式确定压裂后气井的产能。利用该产能模型进行实例分析，发现凝析气藏压裂返排速率影响气井的产能，返排速率过快或过慢都会降低气井的产能。中原油田白庙断块沙三中亚段以100m^3／d左右的初始返排速率返排，压裂后将获得最高产能15000m^3／d。     

硅酸盐/聚乙烯醇抑制性能研究

非常规储层体积压裂施工液体用量大,返排液多,返排液中含有各种地层离子、残余添加剂、悬浮物等,无害化处理难度较大。介绍了国外体积压裂返排液的处理方式,并结合四川盆地的特点,形成了适合于四川盆地非常规储层体积压裂返排液回收利用处理流程。室内研究表明,体积压裂返排液中的残余添加剂浓度较低,具有一定的矿化度,采用回收利用处理流程进行处理后,其摩阻与清水配制的体积压裂液相当。现场应用也进一步表明,体积压裂返排液处理后配制的液体摩阻性能与清水配制的相当。现场获得了良好的储层改造效果,节约了配液用水,减少了废弃物排放,实现了节能减排。     

压裂返排液不落地回收处理技术在苏里格气田的应用

随着苏里格气田水平井改造、体积压裂工艺、混合水压裂方式、工厂化作业等实现推广应用,返排液量剧增,尤其是新环保法实施后,不允许挖建防渗排污坑,环保形势异常严峻。急需研发返排液不落地回收处理技术,实现其重复再利用。针对返排液中含有大量天然气、压裂砂、悬浮物,压力高、分离处理难度大等难题,优化形成了压裂返排液在线连续处理技术,主要包括管线节流控制模块、高压除气模块、低压除气除砂模块、精细化过滤模块和浓残液蒸发模块,经过10μm精细过滤,得到纯净的压裂返排液。进一步化学处理后,添加稠化剂等重新配液用于下次压裂施工,重复利用率达到90%以上,少量浓残液采用蒸发处理。现场先导性试验23井次,回收液体44 649m~3,取得了显著的社会、经济效益,为国内压裂返排液环保处理技术的创新发展提供了借鉴。     

压裂返排液重复利用技术现状及展望

随着油气田开发规模的日益扩大,压裂作业用水量逐渐增大与压裂返排液产生量大、返排液无法直接外排的矛盾日益突出。将返排液进行处理后再回用无疑是目前解决该难题的有效途径。针对我国压裂返排液重复利用研究与应用现状,从返排液处理过程中面临的技术问题、可回收压裂液体系的研发、返排液处理工艺及处理装置的改进等几个方面进行了系统介绍,指出处理后回用是返排液处理的最佳途径,也是未来油气田工业发展的必然趋势。返排液回用技术应该从可回收压裂液体系的研发及返排液回用处理工艺改进两方面入手,进一步完善和推广该技术在油气田开发过程中的应用。针对目前返排液回用技术存在的问题提出了建议,以期为我国返排液重复利用技术的发展提供指导。     

《一种应用于天然气井的回收压裂液》发明专利获得授权

由中国石油西南油气田公司天然气研究院(以下简称天然气研究院)申请的《一种应用于天然气井的回收压裂液》发明专利获得授权(专利号ZL 20111 0238850.1)。该项专利主要针对四川气井多位于丘陵、山区,井场附近缺乏足够的、合适的压裂液配液用水问题以及压裂作业后产生的大量返排液难处理、环境风险大等问题开发出的一种压裂液循环利用技术。该技术主要包括具有耐剪切、低伤害、可回     

锦州20-2终端轻烃回收制冷工艺方案比选研究

采用pH值摆动法、并流沉淀法制备了Al2O3、TiO2-Al2O3二元复合物、TiO2-MgO-Al2O3和MgO-TiO2-Al2O3三元复合物,并对以其为载体的催化剂进行了催化裂化重汽油加氢脱硫反应性能评价。结果表明,在所制备的TiO2-Al2O3二元复合载体中,TiO2分散在Al2O3表面上,且随其含量的增加TiO2逐渐在Al2O3表面上富集;与TiO2-Al2O3二元复合载体相比,三元复合载体的总孔容和平均孔径减小,但是总酸量增加。相比较而言,TiO2-MgO-Al2O3三元复合载体基催化剂对催化裂化重汽油的脱硫率优于TiO2-Al2O3二元复合载体基催化剂,脱硫率在90%以上,且前者的烯烃饱和率也较低,表明该催化剂具有良好的加氢脱硫选择性。     

Hydrotreating of Maya Crude Oil: I. Effect of Support Composition and Its Pore-diameter on Asphaltene Conversion

Abstract

A systematic study for a concept governing support effect in heavy oil hydrotreating (HDT) catalysts is performed. Different Al₂O₃ and its mixed oxides supports were prepared and CoMo supported catalysts were tested for Maya heavy crude oil hydrotreating. Fresh and spent catalysts are characterized with N₂ adsorption-desorption, element analysis, and scanning electron microscopy-energy dispersion analysis by x-ray (SEM-EDAX), which confirms that coke and metals deposition on the surface of catalyst is most probably near the pore mouth. It is also demonstrated from these results that asphaltene conversion depends on the pore diameter of the catalyst, while other hydrotreating conversions (hydrodesulfurization (HDS), hydrodenitogenation (HDN), and in some extent hydrodemetallization (HDM)) are more likely affected by the nature of active metal distribution. The evaluation of alumina mixed oxide (TiO₂, ZrO₂, B₂O₃, and MgO) supported catalysts indicates that supports with basic nature have better stability than the acid ones.     

Effect of the support nature on the catalytic properties of iron in benzene benzylation

The effect of the support nature on the dispersion, structure, and catalytic activity of iron oxides supported on ZrO₂, TiO₂, ZnO, Al₂O₃, and silicas of different structures has been analyzed using the example of benzene benzylation. The structure and electronic properties of the catalysts prepared from iron acetylacetonate have been studied by Mössbauer spectroscopy. It has been shown that the use of SiO₂, ZrO₂, and ZnO supports characterized by weak oxide–oxide interaction leads to the formation of small iron oxide clusters of a 2–10 nm size, which exhibit the highest activity in catalysis.     

The Support Effect on Hydrogenolysis of Thiophene and Gas–Oil

Abstract

Results are reported on the support effect on the catalytic activity in thiophene hydrodesulfurization (HDS) of sulfided Ni-Mo catalysts supported on pure niobia, mixed oxides of Nb₂O₅-TiO₂ prepared by sol-gel method, and Nb₂O₅/TiO₂ and Nb₂O₅/Al₂O₃ prepared by surface deposition. The prepared samples were characterized using N₂ adsorption at ?196°C, X-ray diffraction (XRD), and temperature-programmed reduction (TPR) techniques. This study showed activity variation as a function of support composition. The activity of niobia-rich catalysts was no longer promoted by the synergy between Ni and Mo. The absence of synergy between molybdenum and nickel on niobia can be explained by the strong interaction of each metal with niobia at the expense of interaction with each other. It was found that 5 wt% Nb₂O₅/TiO₂-supported catalyst was the better catalyst for thiophene HDS. It was shown that by means of an adequate support design it is possible to significantly increase the functionalities of HDS catalysts. Semiconducting supports like TiO₂ can improve the HDS activity by exerting electronic effects on the active phase, helping in this way the formation of sulfur vacancies. The 5 wt% Nb₂O₅/TiO₂ was also tested at high pressure with gas oil feedstock. It is observed with the hydrogeolysis of sulfur compounds against time-on-stream that the activity of this catalyst decreases fast with time.     

CA和EDTA对Co-Mo-P/TiO2-γ-Al2O3选择性加氢脱硫催化剂性能的影响

 制备了添加螯合剂柠檬酸(CA)和乙二胺四乙酸(EDTA)的Co-Mo-P/TiO₂-γ-Al₂O₃加氢脱硫催化剂,并对其进行了BET、SEM和H₂-TPR表征。以FCC汽油重馏分为原料,考察了螯合剂对Co-Mo-P/TiO₂-γ-Al₂O₃催化剂选择性加氢脱硫性能的影响。结果表明,添加CA或EDTA均可不同程度地提高Co-Mo-P/TiO₂-γ-Al₂O₃催化剂的比表面积;适量的加入CA或EDTA可有效改善活性组分在载体上的分散状态,减弱活性组分与载体间的相互作用;加入CA可明显改进催化剂的选择性加氢脱硫性能;而加入EDTA同时提高了催化剂的脱硫活性和加氢活性,没能改善催化剂的选择性加氢脱硫性能。     

Evidence for Autocatalysis and Its Implications for the Kinetics of Hydroprocessing of Petroleum Residues

During hydroprocessing of residual feeds the rate of some reactions tends to increase temporarily despite the continuous deposition of coke and metals on catalyst surface. This rate increase has been attributed to catalytic effect of the contaminant metals such as vanadium and nickel in residual feeds after their deposition on catalyst surface. The portion of metals that deposited on the bare γ-Al₂O₃ surface of the Mo/Al₂O₃ and NiMo/Al₂O₃ catalysts transfers the originally inactive surface to catalytically active. The increase in the rate of HDS, HDAs, and some HDM reactions could only be reconciled assuming the involvement of autocatalysis by the deposited metals.     

Catalytic transformations of mixtures of ethers with aliphatic and aromatic nitriles on solid acids under supercritical conditions

The catalytic conversion of mixtures of ethers with aliphatic and aromatic nitriles in supercritical conditions on zeolites (HY, HCaREEY), individual oxides (Al₂O₃, SiO₂, MoO₃, WO₃, TiO₂), and oxide systems (Al₂O₃-SiO₂, H₈[Si(Mo₂O₇)₅], Al₂(WO₄)₃) has been studied. It has been found that acid catalysts, such as zeolites, mixed oxides, and TiO₂ (anatase), are active at 350°C in the direct synthesis of N-acylpyrrolidines from tetrahydrofuran and nitriles (CH₃CN, n-C₄H₉CN, C₆H₅CN): the product yield reaches 40% and the selectivity is 65–94%. The activity and selectivity of TiO₂ samples increase with an increase in the specific surface area (from 37 to 139 m²/g) or with a decrease in the particle size of anatase (from 43 to 13 nm according to XRD data). The character of interaction of the components of the reaction mixture with the TiO₂ surface has been studied by the TG-DTA technique. After oxidative regeneration, TiO₂ exhibits the initial catalytic properties, suggesting the possibility of its repeated use in the direct synthesis of acylpyrrolidines. Replacing THF by other compounds (diethyl ether, 1,4-dioxane, tetrahydropyran) drastically reduces the yield of respective alkylamides.     

预处理方法对Mo-Ni/γ-Al2O3催化剂加氢脱氧性能的影响

采用浸渍法制备了Mo-Ni/γ-Al2O3催化剂,利用BET、XRD、NH3-TPD等方法对还原态和硫化态Mo-Ni/γ-Al2O3催化剂进行了表征,并以模型化合物乙酸和F-T合成轻质油为原料,研究了还原态和硫化态催化剂的加氢脱氧(HDO)性能。结果表明,还原态催化剂具有较大的比表面积和孔体积,活性组分分散度较高;硫化态催化剂的酸性大于还原态催化剂。还原态催化剂具有比硫化态催化剂更好的HDO催化活性,不论是对模型化合物乙酸还是F-T合成轻质油都能获得更高的转化率;但用模型化合物乙酸的研究结果表明,硫化态催化剂不利于C—C键的断裂。     

Effects of Modified Co-Mo Catalysts for FCC Gasoline HDS on Catalytic Activity

Abstract

In this article, a series of catalysts with HZSM-5/γ-Al₂O₃, HZSM-5/TiO₂-γ-Al₂O₃ as supports, bearing Co-Mo as active components, were prepared, and the catalysts were modified with alkaline earth and VIII, IB metal oxide. The catalysts were evaluated by hydrodesulfurization for QILU FCC gasoline. The experiment results showed that: (1) the RON (research octane number) of effluents rose with the increase of ZSM-5 mass percent in the support, but the HDS ratio reduced; (2) the catalysts with ZSM-5/TiO₂-Al₂O₃ as support had higher HDS ratio but lower RON of effluent; and (3) the catalysts modified with metal oxide had higher RON of effluent, but lower HDS ratio, compared with the stuff, and as to RON of effluent and hydrodesulfurization ratio for the modified catalysts, it had the following order: Ba-modified > Fe-modified > Cu-modified.     

The role of sulfur in modification of active sites of reforming catalysts

The features of the interaction of hydrogen sulfide with the surface of supports (alumina and silica) and catalysts (Pt/SiO₂, Pt/Al₂O₃, Re/Al₂O₃, and Pt–Re/Al₂O₃) have been studied. It has been found that the adsorption of sulfur on the supports is completely reversible. The amount of irreversibly adsorbed sulfur (S_irrev) and S_irrev/metal ratios in the catalysts after treatment in a hydrogen atmosphere at 500°C have been determined. Sulfurization reduces the dispersion of platinum to 5% and increases the amount of ionic platinum on the catalyst surface. Regarding the dehydrocyclization reaction of n-heptane, the optimal amount of sulfur required for sulfurization of the catalyst with the composition 0.25% Pt 0.3% Re/γ-Al₂O₃ (0.3% Zr) is 0.072 wt %.