致密碳酸盐岩气藏体积酸压可行性研究及施工效果 ——以鄂尔多斯盆地下古生界碳酸盐岩气藏为例

针对致密碳酸盐岩气藏难以获得高产、稳产这一难题,借鉴国外页岩气体积改造理念,对鄂尔多斯盆地下古生界致密碳酸盐岩气藏体积酸压可行性进行分析。首先阐述了致密碳酸盐岩气藏体积酸压的增产机理,在此基础上,从储层可压裂性、天然裂缝发育状况、水平主应力差、水力裂缝与天然裂缝夹角4个方面分析了体积酸压在致密碳酸盐岩气藏开发中的优势及其局限性,并针对技术局限性提出了相应的改造策略。研究结果表明,体积酸压可形成复杂的裂缝网络,获得较大的储层改造体积;其增产改造效果与储层中的岩石可压裂性、天然裂缝发育状况及天然裂缝与水力裂缝的夹角密切相关,较大水平主应力差会对裂缝网络的形成产生不利影响,可通过可降解纤维暂堵转向技术或转向酸酸压来弱化甚至消除该影响。先导试验结果表明,18口井体积酸压后比邻近常规酸压井增产60%以上,1个月后,其中7口井的日产气量比常规酸压井高41%以上,说明体积酸压比常规酸压在鄂尔多斯盆地下古生界碳酸盐岩气藏中具有更好的增产效果和较好的应用前景。     

碳酸盐岩储层酸压新技术——固体酸酸压技术

压裂酸化(又称酸压)是改造碳酸盐岩油气层的有效方法，是油气井的重要增产措施。为适应高温碳酸盐岩储层酸压改造的需要，本文提出了一种新型的酸压工艺技术——固体酸酸压工艺技术、该技术首先将酸固化成颗粒，然后用非反应流体压开裂缝并将固体酸携带入裂缝中；并根据所设计裂缝的长度和导流能力确定布酸方式．最后注入释放液，使固体酸释放出酸并与岩石作用，从而实现对裂缝壁面的刻蚀并实现深部改造     

低孔裂缝性致密储层暂堵转向酸压技术及应用

塔里木盆地库车山前井具有超深、超高压、高地应力、 高温的特点,储层主要为低孔裂缝性砂岩,厚度中、巨厚,完井后都需要经过改造才能获得高产。针对裂缝发育的储层,通过酸压改造可以获得高产。为了提高中L巨厚储层纵向改造均匀程度和改造效果,采用暂堵转向缝网酸压技术,取得了很好的改造效果。暂堵转向剂在超高压高温酸压过程中能够憋压暂堵转向,达到纵向均匀改造的目的,施工完成后在高温条件下水解,暂堵剂失去暂堵功能,释放被堵储层产能,从而达到增产的目的。     

异常高压深井裂缝性厚层砂岩储层“酸化+酸压”技术

塔里木油田库车前陆冲断带气藏地层压力高、天然裂缝发育,钻井过程中漏失严重。岩心造缝及岩心流动实验结果表明,常规基质酸化不能有效解除污染,需要能够使天然裂缝张开的"酸压"工艺才能有效解除深部钻井液污染;同时,针对长井段合理布酸需要,推导了黏性暂堵酸化机理,指出增大暂堵酸液黏度有利于合理布酸;结合二者,提出了针对高压天然裂缝性砂岩储层的暂堵酸化+砂岩酸压改造工艺。KS2井现场应用表明,该工艺对改造该类储层适应性强,增产效果显著,对同类储层的增产改造具有一定的指导意义。     

元坝陆相气藏裂缝型致密砂岩储层酸压技术

元坝陆相致密砂岩储层具有低孔、低渗、非均质性强等特征,储层微裂缝发育,加砂压裂造缝困难而施工作业难度大、安全风险高、改造效果差。由于该气藏储层含钙质胶结物或钙屑,因此采用酸压技术是降低储层改造风险的有效措施之一,但常规土酸酸化也面临着酸液滤失大、腐蚀性强、酸蚀速度快、施工泵压高等问题。实验和现场应用试验表明,采用胶凝盐酸和胶凝土酸分别作为前置酸和主体酸进行"前置酸酸压+主体酸闭合酸化"施工能有效降低酸岩反应速度、酸液腐蚀程度、酸液滤失量、施工摩阻和施工泵压,进而降低施工作业难度,确保酸蚀裂缝的高导流能力,获得良好的增产效果,可实现元坝陆相裂缝性致密砂岩储层的有效改造。     

轮南潜山裂缝性油藏酸压工艺评价

酸压改造是轮南油田增储上产的主要技术手段。轮南潜山奥陶系储层埋藏深、地层温度高、孔隙裂缝发育等特征给酸压施工和酸压材料带来诸多困难。在分析了轮南潜山碳酸盐岩储层酸压改造技术难点的基础上,对该油田所采用的深度酸压工艺、泵注程序、施工参数、排液方式等作了详尽讨论,并提出了一些建设性的认识,对类似的储层改造具有一定的指导作用。     

交联酸携砂压裂工艺在碳酸盐岩储层的应用

近年来,针对碳酸盐岩的储层改造,中外已形成了以深度酸压为主体的各种酸压技术,同时还尝试了加砂压裂改造。在分析酸压和加砂压裂不足的基础上,针对长庆气田下古生界碳酸盐岩储层特点开发了交联酸携砂压裂工艺,交联酸压裂液具有黏度高、滤失低、摩阻低、易泵送、酸岩反应速度慢、造缝效率高、返排容易、流变性好、能携砂等一系列优点,从而实现酸液体系深穿透、提高酸蚀裂缝导流能力、延长压后有效期、提高单井产能的目的。从2006年以来先后运用该技术在靖边气田对碳酸盐岩储层进行交联酸携砂压工艺改造试验,与邻近井的其他施工工艺增产效果相比有一定的优越性。     

复杂岩性储层酸携砂压裂技术室内研究

现场实践证明,常规酸化压裂和加砂压裂工艺对复杂岩性储层的改造效果不理想,而多级注入、粘性指进酸压工艺以及闭合酸压技术的成功率较低。针对复杂岩性储层的特点和依据该类储层的改造经验,本文提出了新型 乳化酸携砂压裂工艺。通过对新型乳化酸的性能实验,确定了酸液体系。文中选取高强度陶粒和树脂涂层石英砂,进行单层铺置和多层铺置情况下的乳化酸携砂支撑裂缝导流能力以及酸蚀裂缝导流能力对比实验分析,证实了新型乳化酸携砂压裂技术的可行性和可靠性,为乳化酸携砂压裂技术改造复杂岩性储层,提供了理论和实验基础。     

黄陵油区低孔低渗储层改造配套技术应用及效果分析

黄陵油区延长组长6储层物性差,属低孔、特低渗、低压、低产岩性油层,储层非均质性强,裂缝发育,常规的增产技术改造效果较差。为了提高增产改造效果,分析导致增产改造效果较差的原因,找出适合该区块储层的增产措施。多种增产技术分析机理及现场试验显示,黄陵油区长6储层改造应在主裂缝的基础上沟通更多天然裂缝。现场试验认为,暂堵压裂和组合粒径支撑剂两种改造技术效果较好,可为黄陵油区勘探开发提供参考。     

中国海相碳酸盐岩储层酸化压裂改造技术现状及发展趋势

中国海相碳酸盐岩储层具有埋藏深、温度高、高含硫、孔缝洞发育分布不均匀等特点,酸化压裂改造面临一系列技术难题。在对典型海相碳酸盐岩储层地质特征进行了对比分析基础上,针对酸化压裂改造面临的技术挑战,从高温深井提高酸液有效作用距离的酸液体系、高闭合应力储层提高酸蚀裂缝导流能力的措施、缝洞型储层酸化降滤失措施、复杂地层流体应对技术、复杂结构井分段改造措施等方面对国内海相碳酸盐岩储层酸化压裂改造关键技术现状进行了综合分析,提出了海相碳酸盐岩层增产改造理论及工艺技术发展趋势。该研究结果为海相碳酸盐岩储层增产改造技术的发展提供了技术和理论支持。     

往复式空气压缩机常见故障及处理

介绍了往复式空气压缩机运行中常见故障,分析了产生故障的主要原因,提出了处理方法。     

Clothianidin dissipation in tomato and soil, and distribution in tomato peel and flesh

Clothianidin, a new neonicotinoid insecticide, was systematically evaluated. An analytical method using gas chromatography with electron capture detection was developed. Recoveries were between 92% and 102%, with relative standard deviations from 3% to 5% at three fortified levels. The decrease of clothianidin in tomato and soil samples under field conditions at Beijing, Shandong, and Anhui were determined. The dissipation rates of clothianidin fit first-order kinetics. Its half-lives ranged from 6.7 to 12.7 days in soil, and 7.0 to 11.9 days in tomato. On the suggested pre-harvest interval of 7 days, the distribution of clothianidin in tomato peel and flesh was studied. Most residues were found on the peel. Hence, removing the tomato peel before consumption is advisable. The stability of clothianidin fortified at 0.3 or 3 mg/kg in frozen green and red ripe tomatoes was also determined. The half-life mainly depended on the spiked levels of this pesticide.     

中国致密砂岩气及在勘探开发上的重要意义

致密砂岩气藏系指聚集工业天然气的致密砂岩场晕或圈闭,根据其储集层特征、储量大小及所处区域构造位置高低,可将致密砂岩气藏分为两类:"连续型"致密砂岩气藏和"圈闭型"致密砂岩气藏,前者通常位于构造低部位,圈闭界限模糊,无统一气水界面,往往气水倒置,储源一体或近源;后者位于圈闭高处,上气下水,储量规模较小但产量相对较高。中国致密砂岩气都是煤成气,组分以烷烃气(C1 4)为主,甲烷含量最高,烷烃气具正碳同位素系列;非烃气(主要是CO2和N2)含量低。截至2010年底,中国致密砂岩气的储量和年产量分别占全国天然气储量和产量的39.2%和24.6%,预计将来比例还会提高。与页岩气、煤层气等非常规气相比,中国近期在非常规气勘探开发中应以致密砂岩气为先。     

Aflatoxins and fumonisins in rice and maize staple cereals in Northern Vietnam and dietary exposure in different ethnic groups

Mycotoxins in food are increasingly a food safety hazard concern in particular in developing countries. This study was performed to determine the occurrence and determinants of aflatoxin and fumonisin contamination in rice and maize and to assess health risks through dietary intake exposure among ethnic minority groups in northern Vietnam. A total of 111 rice and 102 maize samples, were tested for occurrence of fungi and mycotoxins, i.e. aflatoxins (AF’s) and fuminisin B (FB). Results showed that 107 (96.4%) rice and 84 (82.4%) maize samples were contaminated by fungi. Aspergillus flavus was found in 68 (61.3%) rice and 30 (29.4%) maize samples, Aspergilus parasiticus in 40 (36.0%) rice and 27 (26.7%) maize samples. AF’s - were detected in 27 rice (24.3%) and 27 maize samples (26.4%) at minimum and maximum levels in rice of 2.06 and 77.8 ng/g and 20.5 and 110 ng/g in maize, respectively. Nine (8.1%) rice and 24 (23.5%) maize samples contained FB at ranges of 2.3–624 ng/g in rice and 5.6–89.8 ng/g in maize. Data collected through interviews and observations in households showed that type of crop, storage duration and presence of fungi, particularly mycotoxigenic fungi were important risk factors for AF’s and FB contamination. Based on daily food consumption data, the estimated average exposure dose of aflatoxin B₁(AFB₁) from rice was 21.7 ng/kg bw/day for adults and 33.7 ng/kg bw/day for children. For FB, the rice based average exposure amounted to 536 ng/kg bw/day for adults and 1019 ng/kg bw/day for children. The calculated excess risk of liver cancer incidence by ingestion of cereals containing AFB₁ was 1.5 per 100,000 adults and 2.3 per 100,000 children per year. The average intake of FB was calculated to be lower than the tolerable diet intake (TDI). Our findings highlight that rice and maize are contaminated with mycotoxins at levels representing actual health hazards for the ethnic minority groups consuming these stable cereals. Proper drying and storage conditions in households are likely to reduce the mycotoxin contamination.     

Aflatoxin M1 in raw and UHT cow milk collected in Bosnia and Herzegovina and Croatia

Aflatoxin M1 (AFM1) concentrations were determined in raw and UHT cow milk samples collected in different regions of Bosnia and Herzegovina and Croatia during the autumn months of 2014. The mean AFM1 levels in the raw milk samples were (ng/kg): 6.22 in Bosnia and Herzegovina, 5.65 in Croatia. In all except one milk sample, AMF1 levels were below the LOQ value of 34.2 ng/kg (ELISA method). In four milk samples, AFM1 concentrations exceeded the EU MRL of 50 ng/kg. Samples were subjected to LC-MS/MS analysis which confirmed elevated values determined by ELISA. Elevated levels were in the range 56.6–132.6 ng/kg. Two positive milk samples from Bosnia and Herzegovina originated from Una Sana Canton, two from Croatia from eastern Croatia. The highest AFM1 levels of 132.6 ng/kg was measured in milk from eastern Croatia. In 214 samples of processed UHT milk from Bosnia and Herzegovina and Croatia, AFM1 ranged from 2.29 ng/kg to 21.4 ng/kg, all below the LOQ value. AFM1 exceeded the EU MRL value in only 0.62% of milk samples, indicating the sporadic use of contaminated feedstuff at farms in both countries.     

改进中加强 创新中发展——改革开放30年企业思想政治工作的实践与探索

改革开放30年来，企业思想政治工作随着形势的不断变化，曾经面临着诸多新问题。企业思想政治工作正是在解决这些问题的实践中不断探索，创新思路和方法，提升效果和水平，成为企业改革、发展、进步的动力源泉。     

Aflatoxigenic fungi and aflatoxins occurrence in sultanas and dried figs commercialized in Brazil

The presence of aflatoxins, Aspergillus flavus and Aspergillus parasiticus in dried fruits was investigated. A total of 62 dried fruit samples were analyzed (24 black sultanas, 19 white sultanas and 19 dried figs). A total of 10 A. flavus isolates were found, nine in one white sultana sample (corresponding to 18% infection) and one isolate in dried figs (2%), and all of them were aflatoxin B₁ and B₂ producers. A. parasiticus was not found. Aflatoxins were detected in 3 of 19 (16%) white sultana samples analyzed and, the limits were not higher than 2.0 μg/kg. In dried figs 11 of 19 (58%) samples were contaminated with aflatoxins and, with exception of one sample that was contaminated with 1500 μg/kg of B₁ aflatoxin, the others had less than 2.0 μg/kg. Neither aflatoxigenic or aflatoxins contaminated black sultanas.     

Aflatoxins and ochratoxin A in dried chestnuts and chestnut flour produced in Italy

The occurrence of aflatoxins and ochratoxin A in chestnut products made in Italy was surveyed. Thirty-seven samples of chestnut flour and fourteen of dried chestnuts were collected from retail outlets located in northern Italy. After extraction and purification through an immunoaffinity column, aflatoxins and ochratoxin A were analysed using both HPLC-FLD and HPLC-MS/MS. The mycotoxin contamination found in this survey was widespread and remarkable. As regards aflatoxins, the incidence of aflatoxin B₁ was 62.2 and 21.4% in chestnut flour and dried chestnuts, respectively; in the same products, the percentage of samples exceeding the value of 2.0 μg kg⁻¹ for aflatoxin B₁ (maximum limit fixed by EC Regulation 165/2010 in dried fruits) was 24.3% and 7.1%. A widespread and high incidence of AFG₁ was also found (40.5%). The maximum values for aflatoxin B₁ and total aflatoxins were 67.88 and 188.78 μg kg⁻¹, respectively (chestnut flour sample). Ochratoxin A occurred in all samples, showing very high values (mean 12.38 and 13.63 μg kg⁻¹ for chestnut flour and dried chestnuts, respectively); the percentages of samples exceeding the limit of 10 μg kg⁻¹ (EU limits for dried vine fruit) were 64.9 and 42.8% for chestnut flour and dried chestnuts, respectively. The maximum value was 65.84 μg kg⁻¹ (dried chestnut sample).