Experiments with scale models of oil collectors for subsea well blowouts — Part II

A previous paper of the same title indicated the feasibility of the collection of oil by an open bottom collector above a blowout with a marine riser above the collector; the whole collection system being driven by gas lift from the blowout gas. That paper was based on small-scale laboratory experiments and it identified the salient dimensionless parameters governing those experiments. This paper describes laboratory experiments on a refinement of the collection system and also describes the results of intermediate scale experiments. The length scale of these experiments was about four times greater than laboratory scale and about one-fourth of full scale. Generally, the intermediate scale results are consistent with the laboratory predictions. Furthermore, two scale-dependent parameters have been identified. The effects of these have been included in an analysis of the results.     

海底油气管道夹具维修技术

夹具维修技术目前已经成熟地应用在陆地和海底油气管道维修作业中。根据夹具维修技术在海底油气管道的应用情况,介绍了海底管道夹具维修方法。针对海底油气管道维修技术中的关键部件海底管道夹具,依据不同密封形式,对"国外夹具"设备性能进行了介绍,并分析了海底管道夹具设备研发设计需依据的标准、关键点,为海底管道夹具研发设计做参考。最后根据我国目前海底管道运行及建设情况,提出了开发海底管道夹具维修技术的建议。     

海底溢油的归宿及输移扩散行为

随着全球经济发展对石油资源需求的急剧增加,海洋石油开发业蓬勃发展。海上石油设施增多,突发性的海底油气管道破损泄露、油气井井喷、平台或钻井装置倾覆等造成的石油泛滥事故与日俱增,平均每年有10万吨以上的石油溢入海洋中,使得海上石油污染日趋严重,严重威胁着海洋的生态平衡,不仅对渔业捕捞、水产养殖和海水综合利用造成了巨大的经济损失,而且对海洋环境和海洋生物资源造成了严重的危害和影响。研究证实,海洋石油泛滥对海洋生态环境的破坏所造成的经济损失,远远超过其直接的经济损失。     

Fuzzy MCDM-based GIS model for subsea oil pipeline route optimization: An integrated approach

Proper pipeline route selection is an integral component of a typical oil exploration and transportation project. Improperly selected routes could have severe consequences including pipe failures, oil spillage, and environmental disasters. Consequently, technologies like geographic information systems (GIS) are increasingly being used to facilitate the oil pipeline route selection procedure—especially for onshore routing projects. Surprisingly, not much has been documented on the application of GIS to offshore pipeline routing. With recent discoveries on the merits of offshore oil exploration, it is necessary to extend the analytical capabilities of GIS to the unique offshore domain. However, concerns have been raised regarding the limitations of GIS in accurately prioritizing diverse selection criteria in typical multi-criteria decision-making (MCDM) problems like route selection. Consequently, this paper addresses the offshore/subsea pipeline routing constraint using a hybrid decision support system (DSS), which integrates a GIS and fuzzy logic-based approximate reasoning (AR) models for optimal performance. The resultant spatial decision support system (SDSS) was successfully applied to a case study in Malaysia. The AR algorithm calculated the significance level of the multiple criteria using various fuzzy linguistic variables and membership functions. The aggregated priority ranking from different pipeline routing experts showed that the overall influence of the environmental criteria (61.4%) significantly exceeded that of other equally important criteria in the study area. These rankings were inputted into the SDSS to simulate various probable routes. Final results accurately highlighted an optimal route, which places a premium on the protection of environmental features in the subsea study area—in alignment with the preferences of majority of the experts.     

渤南油气田海底管道内检测结果分析及评价

运用腐蚀分析的方法, 对渤南油气田海底管道的内检测结果进行了清出物分析、腐蚀规律分析及维修因子分析, 得出了管道的腐蚀规律和安全状况, 并提出了本条海管的运维建议。海底管道内检测结果腐蚀分析方法的应用, 是国内首次将这一办法系统地应用于海底管道内检测结果分析, 对于今后海底管道内检测的结果分析具有开创和借鉴意义。     

基于有限元分析的卷管法管道安装实时研究

采用卷管法铺设管道时,管道和铺设设备之间的接触作用十分复杂,并且管道在弯曲过程中将会产生塑性变形并可能发生局部屈曲,导致管道失效。基于有限元模型(FEM)实时模拟卷管法安装的整个过程,研究管道与铺设设备之间的接触作用;分析管道对于环境载荷和船体运动的动态响应;获得管道的应力应变值以校核局部屈曲。研究结果表明,管道弯矩大部分来源于管道与安装设备间的接触作用,而环境载荷及船体运动对管道的弯曲应力影响较小。     

胜利现河油区侧钻井封堵改层及配套工艺研究与应用

胜利油田现河油区复杂断块油藏开发到中后期剩余油呈现出“小而散”的特点,利用已报废的资源,在老井内进行开窗侧钻,挖掘井间滞留区、局部微高等部位极度分散的剩余油,是提高老区采收率的有效手段。针对侧钻井完井及工艺实施过程中暴露出内通径小、射孔穿深不够、分层开采难度大、油管作套管强度低等问题,重点介绍了新型油层套管外径95mm小井眼套管完井技术及小井眼卡堵改层、封堵封窜配套工艺的研究及应用,该配套技术已在现场得到大规模推广。     

水下采油树设计影响参数分析

通过分析不同类型水下采油树的特点及其优缺点,提出水下采油树设计时所需的主要参数。采油树的类型应根据不同的油田开发模式进行选择,在此基础上再制定水下采油树的整体设计方案。综合考虑水深、油藏的特性、井口装置的型式和采油作业的方式等方面的因素,在保证水下采油树强度、稳定性的条件下,进行具体的结构设计、流动保障设计、热绝缘设计、防腐设计和密封设计。同时,为确保水下采油树的安全性和可靠性,需要特别考虑水下采油树的材料问题,并进行可靠性分析和风险分析。     

BZ19—4海底混输管网优化算法探讨

以海洋油气开发工程为实例,利用HYSYS和PIPEFLOW软件,分析了影响海底混输管网计算的若干因素,指出了HYSYS和PIPEFLOW的适用条件,最终确立了海底混输管网优化算法,提高计算效率。     

撞击载荷作用下水下沉箱防护设施损伤分析

面对通航区很可能发生的船舶抛锚、落物以及沉船等事故造成的危险,使用新型沉箱防护设施对水下生产系统进行安全防护,但目前撞击载荷下沉箱防护设施的安全评估标准并无明确界定。采用有限元方法对水下生产系统沉箱安全防护设施的撞击损伤进行了深入研究,考虑不同落物形状、下落速度、落物质量、碰撞位置对沉箱防护设施撞击损伤的影响。结果表明,锚、长方体落物对沉箱撞击最严重;撞击速度和落物质量与撞击应力成正比;对于非对称开孔的沉箱顶盖,距离开孔较近区域为应力敏感区,受到撞击时撞击应力较大。     

萨北开发区井网加密后剩余油分布再认识

在北二西二类油层及三次加密新井完钻后,通过补绘和完善89个单元沉积相带图,结合动态分析、取心井资料和各类油层的水淹状况对储层砂体进行再认识,描述各类砂体的平面几何形态、组合关系及连通状况。对比分析加密前后的砂体分布变化,总结加密井网条件下各类砂体分布规律。综合分析剩余油分布特征,针对砂体微相形态,进行注采对应关系分析,提出相应的调整措施建议,对改善特高含水期油田开发效果具有重要的指导意义。     

Lateral open boundary conditions for nested limited area models: A scale selective approach

This paper reviews current approaches to the lateral open boundary condition problem for nested regional primitive equation ocean numerical models and proposes a new approach that considers a scale decomposition of the nesting field variables for the barotropic lateral velocity boundary conditions. The Flather [Flather, R.A., 1976. A tidal model of the north-west European continental shelf. Memories de la Societe Royale des Sciences de Liege 6 (10):141–164] open lateral boundary condition is derived from mass conservation considerations and we use this approach to derive a generalized lateral open boundary condition for barotropic velocities. In addition we do a scale selective decomposition of the generalized Flather obtaining new and general lateral scale dependent boundary conditions. The performance of the new lateral boundary conditions have been evaluated in two kinds of experiments: (1) idealized and (2) realistic frameworks. In the idealized framework, as well as the realistic case, the results confirms that the scale selective open boundary conditions improves the solution almost everywhere but in particular in the shallow depth parts of the model domain. In the realistic case the assessment is more difficult and it is connected also to the capability of the nesting and nested model to reproduce the dynamics contained in the observations.     

海底管道止屈器形式与设计方法研究概述

海底管道的屈曲传播特性对于其整体安全性是极其不利的,一旦发生屈曲传播,会使整个海底管道结构发生失效破坏,为了解决屈曲传播问题同时兼顾经济性的考虑,可以在海底管道上安装止屈器。通过对国外已有止屈器资料的广泛深入调研,首先对止屈器的主要形式进行了总结和对比分析,然后对止屈器的设计方法和流程进行了简要总结。为我国深水海底管道铺设过程中止屈器的选择和设计提供有益的参考。     

Performance evaluation of pin-holed pipe anchor for fractured zone in subsea tunnel

The presence of a fractured zone at a tunnel face can threaten the stability of the tunnel by causing water leakage and degradation of the soil strength. In this case, to stabilize the tunnel face, the pore water pressure is generally reduced and the loss of soil particles is prevented by installing drainpipes. The installation of drainpipes, however, can cause the concentration of flow channels and other ground instability problems. In this paper, a novel pin-holed pipe anchor is proposed to overcome the problems occurring in subsea tunnels. The pin-holed pipe anchor is a pipe-type support member designed to reinforce the ground while simultaneously enabling flow into the tunnel. Here, the design requirements of the pin-holed pipe anchor were examined through material tests, and the structural–hydraulic characteristics of the pin-holed pipe anchor were investigated through a model test. Furthermore, the applicability of the pin-holed pipe anchor to an actual tunnel was evaluated by numerical analysis of actual tunnels. Through selection of an appropriate perforated drainage area and bonded length, the pin-holed pipe anchor contributed to the improvement of the structural and hydraulic stabilities of the tunnel.     

Virgin rock temperatures from well logs — accuracy analysis for some advanced inversion models

Temperature data from 18 measurement series obtained during logging of the Oseberg field in the northern North Sea are presented. Because the measurement series are taken at approximately the same depth, they should give identical temperatures after depth correction, and are suitable for assessing the performance of different models used to determine virgin rock temperatures from well log information.We have used this data set to test the properties of the different models given by Shen and Beck (1986). Although these models were built to simulate closely the thermal recovery of a well and are unbiased, the uncertainties in the temperature estimates when applied to real data are found to be no less than those from simpler (biased) models. This fact confirms the conclusion of Hermanrud (1989a) who showed that physical factors other than those presently accounted for significantly influence the thermal recovery of a borehole.     

海底管道维修管卡密封结构的性能分析及测试

密封压力是带压堵漏维修管卡的关键性能。介绍了323.9 mm(API 12英寸)维修管卡样机的总体结构及密封原理,选用接触压力准则作为管卡的密封评价准则,利用ANSYS Workbench软件建立了管卡密封结构的二维轴对称有限元模型,分析了密封结构闭环中薄弱部分在不同密封圈压缩量下的接触压力,然后试验测试了管卡样机密封圈压缩量和密封压力,并与有限元计算接触压力进行了对比。分析结果表明管卡密封结构最薄弱部分的接触压力随着周向密封圈压缩量的增大而增大,且主要是中间接触部分起到密封作用。通过试验验证了理论分析的管卡密封结构最薄弱位置,并发现相同密封圈压缩量下试验测试的密封压力与计算的接触压力近似,两者的变化趋势基本一致。有关分析思路和试验方法可以为管卡密封结构的设计提供重要参考。     

基于监测数据的深水水下井口循环弯矩计算方法

水下井口的疲劳完整性是海洋油气田长期安全开采的前提。工业界往往采用贴应变片直接测量水下井口应变来计算弯矩和疲劳损伤,但水下井口应变片粘贴困难且不能长时间连续工作。采用对水下井口监测方法,基于隔水管—防喷器组—水下井口的运动和力学特性,考虑防喷器组惯性力矩建立系统耦合动力学方程,最终形成基于监测数据的水下井口循环弯矩计算方法。以南海某深水水下井口为例,建立隔水管—防喷器组—水下井口系统有限元模型并进行动态分析,提取隔水管底部张力、转角、防喷器组加速度及转角等参数,代入所建立的系统耦合动力学模型,得到水下井口弯矩与有限元计算结果吻合良好。研究表明只需通过在线监测获得所需的输入数据,无需监测水下井口应变即可获取水下井口循环弯矩。建立的系统耦合动力学模型可为水下井口疲劳完整性评估提供理论依据。     

张力腿平台水下丛式井口圆形布局方法研究

张力腿平台(TLP)水下丛式井口布局设计关系到立管服役期间的安全性,是含有丛式井口平台设计过程中考虑的主要因素。根据TLP立管安装、钻井以及防碰等要求,考虑尾流效应对丛式立管的影响,研究水下丛式井口布局设计准则,对丛式井口—立管系统进行碰撞分析以确定水下井口间距阈值,提出水下丛式井口圆形布局方法和相应的布局设计流程。通过算例对计算方法进行了具体运用。研究表明:与目前采用的"等边三角形网格"方法相比,水下丛式井口圆形布局方法可允许水下整体基盘安装位置误差达到水下井口间距阈值的20%,立管的最大倾角可达到0.5°,安装作业窗口增加1倍以上。本方法对水下整体基盘安装位置误差的容错能力强,能有效扩大丛式立管钻井和安装作业窗口,提高丛式立管作业安全性,研究结果可为TLP丛式井口的设计提供参考。     

波浪破碎下油滴粒径分布理论模型研究

海上溢油在波浪破碎的情况下经常会形成油滴,本文讨论了油滴形成的可能机制,根据量纲分析瑞利法建立了油滴卷入率与能量耗散率、卷入深度等破碎统计物理量的关系。基于量纲分析Π定理并根据毛细数、无量纲卷入时间与粘度比的实验关系,导出了油径谱的理论模型。初步结果表明,理论谱斜率-2.29与观测谱斜率-2.3符合良好,剪切率、表面张力、油滴半径、油和水的黏度等因素是影响油滴总数的主要原因。     

普通稠油水淹层顶部剩余油水平井技术界限研究——以孤岛中二北Ng5为例

具有较大边底水的中等厚度的普通稠油油藏,长期以来利用直井开发,效果不佳。在高油价的有利条件下,针对该类油藏,提出了利用水平井挖潜,以孤岛中二北北部Ng5稠油区块为例,建立实际参数的概念模型,分不渗透隔层和无隔层两种类型,对水平井的开发方式、最小有效厚度、水平井垂向位置、排液量、井距及水平段长度进行了优化,给出了对应两种类型的水平井技术界限,现场实施取得了良好的开发效果。