可循环泡沫钻井完井液防地层污染数值模拟

在现场施工中难以观察可循环泡沫钻井完井液的井下情况,为模拟其对地层的保护机理,建立了合理的地层孔隙简化模型,对可循环泡沫钻井完井液在井下如何防止地层污染的流场规律进行数值模拟分析,模拟结果表明可循环泡沫钻井完井液的气泡可以进入地层,有效地阻止了钻井液组分进入地层伤害储层,并随着孔隙尺寸不同而具有较好的适应性。在现场试验中也证实了可循环泡沫钻井完井液能够很好地保护油气层、防止储层受损伤。     

网站互动评论

下期预告：与机遇握手 共赢梅河口 当乘坐飞机或是乘坐列车来到沈阳、长春、吉林时，三座城市对角线上的一个美丽城市很快就展现于您的眼帘：独特的区位优势.丰富的资源禀赋、蒸腾的建设场面、优雅的城市环境……这些难道不会让您产生一种“埋下希望种子，必有丰厚回报”的冲动？     

建筑评论

正如同许多其他领域,建筑领域的“设计”也是由“技术”所支撑着的。没有技术支持的建筑设计只能在表示出有限的设计意图的可能性之后便草草收场,无法继续深化。不幸的是,那些不具备技术本质或没有技术尝试的建筑,有一些会在第一眼让人觉得是不错的设计,但事实上我们所知的范围内更多的情况是因为缺少技术内涵致使业主遭受非常不良的结果。     

名家点评

走向精品之路的传统四合院有机更新 吴良镛 几十年来,许多有识之士在北京旧城更新方面做了大量的探索性工作,也取得了一些成绩.     

前门十议

正阳门老北京亦称前门。其外,明清以来一直是北京最有名的商业街,20世纪70年代后随京城新商圈兴起,逐渐没落。借旧城保护、整治之机,21世纪初开始酝酿的前门地区保护、整治工程,已于3年前进入实施阶段,现正轰轰烈烈地进行着大规模的工程建设。笔者有幸参加此盛举,耳闻目染,身经多次反复历练,对旧城的保护和整治小有心得,择十题抒一孔之见于后。     

Comments by a Councilman

This article presents results from the first statistically significant study of traffic forecasts in transportation infrastructure projects. The sample used is the largest of its kind, covering 210 projects in 14 nations worth U.S.$59 billion. The study shows with very high statistical significance that forecasters generally do a poor job of estimating the demand for transportation infrastructure projects. For 9 out of 10 rail projects, passenger forecasts are overestimated; the average overestima-tion is 106%. For half of all road projects, the difference between actual and forecasted traffic is more than ±20%. The result is substantial financial risks, which are typically ignored or downplayed by planners and decision makers to the detriment of social and economic welfare. Our data also show that forecasts have not become more accurate over the 30-year period studied, despite claims to the contrary by forecasters. The causes of inaccuracy in forecasts are different for rail and road projects, with political causes playing a larger role for rail than for road. The cure is transparency, accountability, and new forecasting methods. The challenge is to change the governance structures for forecasting and project development. Our article shows how planners may help achieve this.

This article was substantially reproduced in the article "Inaccuracy in Traffic Forecasts", published in 2006 in Transport Reviews [Bent Flyvbjerg, Mette Skamris Holm, and Søren L. Buhl, Transport Reviews, Vol. 26, Issue 1, 2006, pp. 1–24 (retracted)] and is the subject of a Notice of Redundant Publication in Journal of the American Planning Association, Vol. 78, Issue 3, page 352, 2012. doi:http://dx.doi.org/10.1080/01944363.2012.719432