压裂水平井产能预测方法研究进展

水平井压裂技术在低渗透及非常规储层中得到了广泛应用,压裂后水平井的产能预测关系到油田开发方案的制定,因此,国内外学者对压后渗流模型的建立和求解方法做出了不懈的努力。本文详细回顾了国内外学者所建压裂水平井产能预测模型及求解方法,指出了不同模型和求解方法的优缺点,并展望了压裂水平井产能模型的发展方向。     

基于物质平衡方程的页岩气井产能预测方法

页岩气井产能受地质和压裂改造参数综合影响,在开发初期,难以确定可靠的地质模型来预测气井产能。为了快速、准确地预测气井产能,在研究页岩气物质平衡方程和产能方程的基础上,考虑吸附气和异常高压气藏岩石弹性能量影响,建立了基于物质平衡方程的页岩气井产能预测方法,该方法需要参数较少,可在开发初期快速对页岩气井产能进行预测。涪陵地区X1井实例计算表明:该方法综合考虑了页岩气吸附气解吸、异常高压气藏岩石弹性能量的影响,产能预测结果准确、可靠;吸附气对气井累产气量影响明显,约占总累产气量17%,对定产生产气井的稳产期影响不大;吸附气的贡献在2.5~4年逐渐体现出来,定压放喷生产初期产量高,地层压力下降快,吸附气的产出贡献比控制产量的定产生产方式要早;考虑岩石弹性能量的影响,气井稳产时间和累产气有所增加,但影响不明显。     

Moving beyond ‘more crop per drop’: insights from two decades of research on agricultural water productivity

ABSTRACT

Concern over increasing water scarcity has led to the introduction of the concept of agricultural water productivity and an emphasis on interventions to achieve ‘more crop per drop’. Yet, a strong debate continues on how the concept is to be defined and used. Drawing largely from the irrigation literature, the origins of the concept and its methodological developments are reviewed, and its use in applied work over two decades is discussed. Based on this analysis of conceptual and applied research, key insights into the concept’s contributions and limitations are presented, as well as opportunities for further refinements.     

非常规气举采油技术在涠洲11-1油田的应用

涠洲11-1油田东块A12h井电泵故障濒临停产,而平台可移动修井机已移至其他油田,短时间内无法修井检泵作业的情况下,通过改造地面注气流程,利用平台分离器高压天然气供气,采取非常规气举技术进行采油。涠洲11-1油田非常规气举采油技术应用结果表明,非常规气举技术在海上油田特殊情况下可有效恢复油井的正常产能,保证油井生产时效,从而保证了油田的正常生产。该技术拓展了海上平台的采油方式,为类似情形下恢复油井产能提供了可借鉴的方法。     

卫城油田低孔低渗储层产能模型研究

产能预测是一种对储层产油能力进行综合评价的技术,对油气田的勘探与开发有着极其重要的意义。对于中、高孔渗油藏,油水渗流基本服从达西渗流定律,产能预测相对来说比较简单。而对特低渗透储层而言,渗流机理非常复杂,影响产液能力因素也更多更突出,产能预测难度非常大。对低孔低渗储层产能进行正确评价既是提高油气田勘探效果的关键环节,又可以为开发的部署与规划提供重要的基础数据。     

A Meta-frontier method of decomposing long-term construction productivity components and technological gaps at the firm level: evidence from Malaysia

There is a need for a better approach to measure construction productivity rigorously, multilaterally, longitudinally and decomposed into its components. In response, this paper offers a robust approach to analysing construction productivity at the firm level that has been lacking in the industry to date, by measuring the Total Factor Productivity (TFP) of 37 public-listed Malaysian construction firms over 14 years (2003–2016), based on the Färe-Primont index. In comparing different groups of building, civil and specialist construction firms, this is the first application of a meta-frontier framework to capture the technological gaps involved. Based on the construction firms’ financial data, it is found that TFP improvement generally occurs due to Technical Efficiency (TE) and Scale-Mix Efficiency (SME) (largely scope economies), and significant technological gaps exist among different groups. Moreover, the industry suffered a decline in technologically related production environment over the period – prompting the conclusion that long-term policy engagement should focus on technological improvements. The paper provides a robust approach to analysing construction productivity at the firm level that also can be used for accessing productivity components and technological gaps in construction and other industries.     

Effect of mass recovery evaporator temperature and condenser temperature on the performance of a solar adsorption-based desalination plant

Water scarcity increases alarmingly as the population increases. Over the years, a number of salt water desalination techniques have been proposed and reached limitations. The requirement of minimum energy is very well satisfied by an adsorption system, since it can operate with low-grade energy and waste heat exhaust from most industries. The first part of this work discusses the effect of condenser and evaporator temperatures on the performance of silica-gel adsorption cycle mathematically. The second part discusses the performance variations due to mass recovery in the two-bed adsorption system mathematically. It was found that the reduction in condenser temperature and increase in the evaporator temperature both increase the fresh water productivity and cooling capacity of a plant. A desalination plant with mass recovery assistance is superior in performance than the conventional plant. Portable water productivity of 8?m³/day/ton is achieved with the condenser temperature of 15°C and the evaporator temperature of 30°C.     

建设项目评标中存在问题的技术解决方法

针对目前工程量清单招标中存在低于成本价竞标的问题,从技术与经济相结合的角度出发,基于资源优化配置理论和劳动定额制定原则,提出了施工资源评定法和劳动生产率评定法,以提高评标办法对报价合理性和可行性的评判,从而降低低于成本价竞标者中标的可能性,维护正常的招标投标秩序.     

基于双部分丢弃的模拟移动床产率提高策略

在保证产品纯度的情况下,提出一种带额外色谱柱的双部分丢弃策略以提高模拟移动床的产率。通过将工艺点选取在纯提取产品和非纯提余产品区域以增大进料流量,并将由此导致的含较多杂质的提余产品暂时丢弃。丢弃的提余产品作为循环进料通入到一个额外色谱柱中以进一步分离,部分不能达到指定纯度的额外产品被永久丢弃。在模拟移动床和额外色谱柱处分别收集到的产品组成总产品。分析了工艺点的选取、提余产品的积分纯度阈值和额外产品的积分纯度阈值对总产品性能参数的影响。研究结果表明,所提策略能够以较高的回收率利用原料,且能够显著提高分离过程的产率,其分离效果优于传统的模拟移动床工艺和部分丢弃策略。