基于节理塑性模型的页岩地层水平井井壁稳定性分析*

为研究层理页岩地层中水平井井壁失稳机理,基于流固耦合理论,考虑地层渗透率和强度各向异性,运用节理材料模型对水平井井周塑性失稳区域分布规律进行数值分析。结果表明:钻井液流体侵入导致井周孔隙压力分布呈各向异性,页岩水平井井周破坏形态为四角形状,且随时间增加逐渐向地层内部延伸形成剪切带;在考虑井壁渗透情况下,增大钻井液密度并不能显著改善页岩井壁失稳状况,加强钻井液封堵性对维护井壁稳定具有重要作用。     

附属管线对隔水管涡激振动影响的数值模拟研究

涡激振动现象会引起海上钻井平台隔水管发生结构失稳和疲劳破坏。针对附属管线安装位置对隔水管的涡激振动影响开展了三维数值模拟,采用CFD大涡模拟计算方法,对不同来流角度α、直径比d/D和间距比G/D情况进行数值模拟,得到隔水管所受的升力和阻力变化情况并对其进行频谱分析。模拟结果表明:隔水管所受的升力和阻力对来流角度的变化很敏感,阻力系数CD和升力系数均方根CrmsL随来流角α的增大而减小,并在α值为30~45°范围内降至最低;用来表征隔水管后方漩涡脱落频率的St数随α的增大略有增大,但总体稳定保持在较低值范围。根据模拟结果,附属管线在直径比d/D值应在0.2~0.3范围内,间距比G/D值在0.3~0.4范围内的布置方式对隔水管涡激振动的抑制效果最为理想。     

含硫气井井筒完整性风险评价研究

针对含硫气井开发过程中井筒完整性失效风险,建立了含硫气井风险评价模型。采用Bow-tie模型将井筒完整性的失效形式分为水力屏障失效、实体屏障失效和操作管理屏障失效3个方面,确定了含硫气井井筒完整性失效的28个风险因素;基于层次分析法定量确定了各风险因素的权重,通过风险矩阵法评估了风险因素发生的可能性与严重程度,实现了对井筒完整性风险等级的划分。将以上方法对某含硫气井进行了应用,确定了该井的风险等级及主要风险因素。研究结果表明:建立的风险评价模型能够对含硫气井井筒完整性进行评价,确定风险等级。该方法的应用有助于降低含硫气井的事故风险,可为含硫气井完整性现场管理提供参考。     

连续管钻塞水平段铁屑运移机理研究

针对水平井段连续管钻磨桥塞时铁屑运移规律尚认识不清,沉积的铁屑堆积在井下工具周围而导致卡钻的问题,在欧拉坐标系下考虑相间滑移速度以及铁屑流参数,建立了三维井眼环空铁屑运移模型,采用Standard κ－ε湍流模型及SIMPLEC算法进行数值计算,研究了环空偏心度、钻塞液排量、铁屑直径、钻塞液粘度和铁屑体积分数对水平段铁屑运移的影响,得到了环空铁屑体积分数和固定铁屑床高度的分布规律。研究表明:增大钻塞液排量、减小铁屑直径、减小环空偏心度、增大钻塞液粘度和减小铁屑体积分数,可提高连续管钻塞水平段铁屑运移效率。水平段铁屑运移机理研究可为连续管钻磨桥塞卡钻问题的解决提供技术支持。     

环空带压气井液位测试方法改进研究及应用

为了实时有效监测环空带压气井的液面位置,评价环空带压气井的风险,在传统回波定位技术基础上,提出了1种基于自相关分析的气井液位声波测试方法;建立了环空液位声波测试实验系统,开展了不同起爆压力下环空液位测试实验;对检测到声波信号进行平滑降噪和自相关分析,计算液面位置,并与真实液位进行对比分析;将该方法在现场含噪声的环空带压气井液位测试中进行了应用。结果表明:该方法能够对环空液位声波测试信号中的液面反射波进行有效提取;相比较现有在测试信号平滑降噪基础上提取的液面位置,降低了计算误差;同时,该方法能够在井下噪声环境中实现微弱液面反射声波的有效提取,其处理后的信号峰值指标更为突出,提高了测试系统对液位的识别能力,便于自动识别。     

油田井场废水高效絮凝剂研究与应用

文章分析了长庆油田井场废水特点,研制了三种适合于长庆油田井场废水处理的絮凝剂。将研发的絮凝剂与普通PAM分析进行对比,新型絮凝剂对色度及石油类的去除比常规PAM去除率提高了50%左右,悬浮物及COD的去除率亦分别提高了20%和30%。现场应用表明,研发的絮凝剂具有良好的应用效果。     

ANALYSIS OF PUMPING TESTS: SIGNIFICANCE OF WELL DIAMETER,PARTIAL PENETRATION,AND NOISE1

ABSTRACT: The nonlinear least squares (NLS) method was applied to pumping and recovery aquifer test data in confined and unconfined aquifers with finite diameter and partially penetrating pumping wells, and with partially penetrating piezometers or observation wells. It was demonstrated that noiseless and moderately noisy drawdown data from observation points located less than two saturated thicknesses of the aquifer from the pumping well produced an exact or acceptable set of parameters when the diameter of the pumping well was included in the analysis. The accuracy of the estimated parameters, particularly that of specific storage, decreased with increases in the noise level in the observed drawdown data. With consideration of the well radii, the noiseless drawdown data from the pumping well in an unconfined aquifer produced good estimates of horizontal and vertical hydraulic conductivities and specific yield, but the estimated specific storage was unacceptable. When noisy data from the pumping well were used, an acceptable set of parameters was not obtained. Further experiments with noisy drawdown data in an unconfined aquifer revealed that when the well diameter was included in the analysis, hydraulic conductivity, specific yield and vertical hydraulic conductivity may be estimated rather effectively from piezometers located over a range of distances from the pumping well. Estimation of specific storage became less reliable for piezometers located at distances greater than the initial saturated thickness of the aquifer. Application of the NLS to field pumping and recovery data from a confined aquifer showed that the estimated parameters from the two tests were in good agreement only when the well diameter was included in the analysis. Without consideration of well radii, the estimated values of hydraulic conductivity from the pumping and recovery tests were off by a factor of four.     

含硫化氢天然气井公共安全技术标准体系比对研究

含硫化氢天然气井重大事故对公众安全具有重大危害,建立和完善含硫化氢天然气井公共安全技术标准体系,对于加强含硫气井应急管理,保护人民群众生命健康安全具有重要意义。针对含硫化氢天然气井公共安全技术标准,调研了加拿大和美国等国外含硫气井开发典型地区的含硫化氢天然气井公共安全技术标准体系,分析了其体系构成和标准内容,总结了其特点,比对国外含硫化氢天然气井公共安全技术标准体系,基于对国内的调研,分析了我国含硫化氢天然气井公共安全技术标准体系存在的不足;通过对国内外三百多项相关标准的调研和比对分析,基于我国实际现状,分析提出了标准体系建设的相关建议,为我国含硫化氢天然气井公共安全标准体系的完善和标准制定工作提供参考。     

Long‐term effects of Hurricane Katrina on the psychological well‐being of evacuees

Hurricane Katrina of August 2005 forced more than one million people to evacuate the Gulf Coast of the United States. This study examines the psychological health and well‐being of a subset of evacuees to determine the prevalence of ongoing mental health problems. Interviews were conducted with 101 adults who evacuated to Louisville, Kentucky, and were living in the state at the one‐year anniversary of the event or had recently returned to the Gulf Coast. The psychological health and well‐being of respondents was evaluated using several well‐validated measures. More than one‐half met the criteria for post‐traumatic stress disorder and a majority were suffering from depression and anxiety. The mean quality of life score was 0.6 on a scale from 0–1, suggesting that adaptation and return to pre‐hurricane well‐being had not occurred 12 months after the storm. The potential for long‐term psychological damage exists in this sample of Hurricane Katrina evacuees. Results suggest other evacuees may also be at heightened risk.     

水井酸处理中排污水水质变化规律

盐酸洗井是增大碳酸盐岩井涌水量的一种有效措施。大量盐酸的广泛应用,严重影响地下水质,必须充分考虑到它带来的环境污染问题。本文对水井经酸处理后排放的污水水质作了监测,进而对水质的变化规律作了研究。