Scheduling workover rigs for onshore oil production

Many oil wells in Brazilian onshore fields rely on artificial lift methods. Maintenance services such as cleaning, reinstatement, stimulation and others are essential to these wells. These services are performed by workover rigs, which are available on a limited number with respect to the number of wells demanding service. The decision of which workover rig should be sent to perform some maintenance service is based on factors such as the well production, the current location of the workover rig in relation to the demanding well, and the type of service to be performed. The problem of scheduling workover rigs consists in finding the best schedule for the available workover rigs, so as to minimize the production loss associated with the wells awaiting for service. We propose a variable neighborhood search (VNS) heuristic for this problem. Computational results on real-life problems are reported and their economic impacts are evaluated.     

临床药师医嘱审核在静脉药物集中配置中的作用

分析医院静脉药物集中配置情况,探讨临床药师通过医嘱审核在静脉药物配置中心（PIVAS）的作用,促进了临床合理用药。方法：针对医院PIVAS为内科病房开展工作,按照随机抽样原则,分别抽取2013年7~12月（A组）及2014年1~6月（B组）的住院用药医嘱中各抽取4000份,进行分析和统计。结果：A组不合格医嘱有377份（占医嘱9.43%）,B组住院用药医嘱中,不合格医嘱有94份（占医嘱2.35%）。结论：通过医嘱审核,临床药师在PIVAS的工作中,将控制不合理用药关口前移,促进了临床合理用药,提高了医院的现代化医疗质量。     

储层保护型修井液技术系列的研究及应用

从储层伤害的机理出发,结合修井液的特点对其造成的储层敏感性伤害进行了分析,分别从减少修井液的固相和液相伤害进行了体系构建。结合实验研究研制出了封堵性能好、抑制性强、易返排、储层保护效果优异的修井液技术体系及配套完井液;并以南海西部乐东15-1气田为目标区块进行了现场应用。结果表明,该技术系列能够有效地保护油气层,提高修井作业后的产量恢复效率,效果十分显著。     

修井作业浮动式井口防溅保护器的研制

修井作业中,井口的废液对施工效率及人身安全的影响巨大。如何防止废液四溅显得非常重要。针对目前应用的防溅保护装置的不足,提出了一种新颖的浮动式井口防溅保护器,并对该装置进行了材料的优选以及关键部件受力计算。该装置设计新颖、操作简单、废液收集效率高,可广泛应用于修井作业中。     

A comparison of three metaheuristics for the workover rig routing problem

The workover rig routing problem (WRRP) is a variant of the Vehicle Routing Problem with Time Windows (VRPTW) and arises in the operations of onshore oil fields. In this problem, a set of workover rigs located at different positions must service oil wells requesting maintenance as soon as possible. When a well requires maintenance, its production is reduced or stopped for safety reasons and some workover rig must service it within a given deadline. It is therefore important to service the wells in a timely fashion in order to minimize the production loss. Whereas for classical VRPTWs the objective is to minimize route length, in the WRRP the objective is to minimize the total lost production, equal to the sum of arrival times at the wells, multiplied by production loss rates. The WRRP generalizes the Delivery Man Problem with Time Windows by considering multiple open vehicle routes and multiple depots. This paper compares three metaheuristics for the WRRP: an iterated local search, a clustering search, and an Adaptive Large Neighborhood Search (ALNS). All approaches, in particular ALNS, have yielded good solutions for instances derived from a real-life setting.     

三次采油区块套损井修复技术研究与应用

目前,三次采油主要以聚合物驱、三元复合驱为主,由于注入介质自身的特性,造成此类区块套损类型复杂,修复难度大。主要存在以下问题:一是区块套损机理认识不清,工艺措施针对性不强;二是胶结物携带砂、泥岩块堵塞井筒,循环泄压困难;三是吐砂井上顶管柱,冲砂进尺不理想;四是小直径、活性错断、大段弯曲井打通道时效低、成功率低。这些套损井若不能得到及时有效治理,将严重影响区块的整体开发部署和产能的提高。通过从工程、地质方面分析套损原因,开展三次采油区块套损井修复技术研究,形成了以套损形态预测、加压起下及找打通道技术为主的技术系列,现场试验起到较好效果。