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旋转磨料射流套管开窗预测模型及应用 被引量:3
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作者 刘康乐 魏艳 +1 位作者 李莎 王方祥 《断块油气田》 CAS 北大核心 2017年第4期578-582,共5页
套管开窗径向水平井技术有助于提高低渗透储层的油气采收率,旋转磨料射流套管开窗方式是该技术新的发展方向,套管开窗直径和开窗深度是评价开窗效果的2个重要指标。由于无法实时监测井下开窗过程,需对开窗效果的预测进行研究。但套管开... 套管开窗径向水平井技术有助于提高低渗透储层的油气采收率,旋转磨料射流套管开窗方式是该技术新的发展方向,套管开窗直径和开窗深度是评价开窗效果的2个重要指标。由于无法实时监测井下开窗过程,需对开窗效果的预测进行研究。但套管开窗效果与旋转磨料射流参数之间存在复杂的非线性关系,使得传统预测方法的精度偏低。为此,文中提出了一种基于基因表达式编程建立套管开窗预测模型的新方法。通过遗传编码、遗传操作和适应度评估,建立了开窗直径和深度的直观数学表达式预测模型,利用套管开窗综合实验结果对该方法的准确性、实用性进行了验证。结果表明:该方法的预测精度较高,与检验样本相比,开窗直径和深度的平均误差分别为5.5%和4.4%;将预测模型的计算结果与套管开窗综合实验结果相比,开窗时间的误差为6.1%,开窗直径的误差为4.5%。因此,基因表达式编程算法能够更精确地推导出反映实际数据的最佳拟合函数,建立的预测模型可用于指导旋转磨料射流套管开窗现场施工。 展开更多
关键词 旋转磨料射流 套管 开窗效果 基因表达式编程 预测模型
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LONG-TERM OUTCOMES OF FENESTRATED DISCECTOMY FOR LUMBAR DISC
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作者 潘玉涛 曹鹏 +4 位作者 梁裕 龚耀成 郑涛 张兴凯 吴文坚 《Journal of Shanghai Second Medical University(Foreign Language Edition)》 2008年第2期127-130,134,共5页
Objective To evaluate the long-term outcomes of fenestrated discectomy for lumbar disc herniation and analyze the correlative influence factors. Methods Eighty-two cases of lumbar disc herniation, from February 1996 t... Objective To evaluate the long-term outcomes of fenestrated discectomy for lumbar disc herniation and analyze the correlative influence factors. Methods Eighty-two cases of lumbar disc herniation, from February 1996 to May 1999, were retrospectively studied. All patients were treated with simple fenestrated discectomy. The average follow-up time was 8 years and 7 months (from 7 years tolO years and 3months). There were 13, 38 and 31 cases at 13 - L4, L4 - L5 and L5 - S1 level, respectively. Results The average scales before operation were as following : Japanes Orthopaedics Association ( JOA ) scale 6. 5 ( 5 - 9 ) , visual analysis scale ( VAS) of low back pain4.8 (0-8). and VAS of sciatica 7.2 (4-10). At the final follow-up, the above parameters were 13.2 ( 10 - 14 ), 1.8 (0 - 10) and 1.2 (0 - 7), respectively. The average increase ratio of JOA scale was 78. 8%. The average disc-vertebra height ratio ( Mochida method) was 80.2%. At the final follow-up, 7 cases reoccurred disc herniation. The final clinical satisfaction rate was 80% ( modified Macnab method ). Conclusion With appropriate surgical indications, the successfid long-term outcomes could be expected with fenestrated discectomy. Discectomy improves sciatica to a greater extent than low back pain. The occurrence of low back pain is related to intervertebral disc height, segment stability, disc degeneration, and lumbar muscle disability. 展开更多
关键词 lumbar disc herniation fenestrated discectomy long-term outcome
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