The floating platform plays an important role in the development of the deepwater oil &gas resources.For the good motion performance and high technological maturity,the tension leg platform (TLP)has been used widely.The harsh environmental condition in the South China Sea,especially the typhoon and internal wave brings new challenges to the design of deepwater floating platforms.Thus the time domain coupling method was used here to analyze the motion offsets and tendon force of a TLP in the South China Sea experienced with internal wave.Accord-ing to the research,the internal wave makes a great influence on the TLP performance.The re-search results may provide good proposal to the design of a new TLP.

针对某深水半潜式钻井平台,为其设计1套多点扩展式锚泊系统.采用数值方法计算船体与系泊系统耦合动力响应,并通过水池模型试验对计算结果进行验证.结果表明,在钻井作业与生存工况下该平台的最大水平偏移与系白张力均满足规范要求.通过计算结果与试验结果的对比发现,由于水池试验采用等效截断方法低估了系泊缆绳本身的质量惯性与所承受的流体载荷,导致系泊张力的计算结果略大于实验结果.

半潜式钻井平台是深海油气资源开发的重要装备,电气系统对平台的钻井作业、位置保持、人员生活具有重要作用.该文阐述了半潜式钻井平台电气系统的基本构成,并结合设计案例讨论了设计依据、设计工况、负荷分析、主电源选取、配电系统设计、接地方式、谐波治理与抑制、电气设备布置等方面的问题,同时探讨了动力定位与锚泊定位两种半潜式钻井平台电气系统的主要区别与特点.

The status of development process and engineering application of the platform is intro-duced in this paper,the construction and mating plan is discussed,and the fatal accidents ever happened is listed,and the development trend is summarized.Finally some proposals are put for-ward for the application in South China Sea.

半潜式钻井平台是深海油气资源开发的重要装备,通常有两个浮箱作为提供主要浮力的组件,不同的船型设计会采用不同的浮箱端部形状,可因此会影响平台的总排水量并改变平台的运动性能.该文以某半潜式钻井平台为研究对象,分别对尖形、半圆形、倒角方形三种代表性浮箱端部形状的船型方案进行了运动性能计算,并对计算结果进行了横向对比.结果表明,在主尺度不变的前提下,相对于尖形端部浮箱而言,半圆形、倒角方形端部浮箱有利于提高的整体装载能力,同时平台的运动性能没有显著改变.

半潜式钻井平台是深海油气资源开发的重要装备,压载系统是平台上重要的保船系统,起到调节平台吃水及平衡的作用.该文阐述了深水半潜式钻井平台压载系统的特点、设计原则、设备选型及管系设计、安全控制等,并以某平台为例归纳总结了压载系统的设计方法及要点.

半潜式钻井平台是深海油气资源开发的重要装备之一,其运动性能直接影响到平台钻井作业能力,因而是计算分析的重点.设计初期阶段需要对若干代表性工况进行运动性能分析和对比,然而平台作业时装载工况多达几十种,不同的装载工况可能导致平台吃水以及重心位置的显著变化,因此就需要研究此类平台的运动性能在不同装载工况下的变化规律,进而选取平台最不利状态作为计算分析中需要重点关注的装载工况.该文以某深水半潜式钻井平台为研究对象,采用水动力分析软件对其不同装载工况下的运动性能进行计算和对比分析,获得了平台吃水以及重心高度对其运动幅值与加速度值的影响趋势,并对运动性能分析工况的选择提出了建议.

Semi-submersible drilling rig plays an important role in the development of offshore oil& gas.There are 243 semi-submersible drilling rigs all over the world and 13 in China,more rigs need more technical support.Most of the rigs experienced updates and conversions in its lifespan to improve the operation performance and efficiency.Different update purposes have been studied also some conversion plans.Main changes which happened to the rigs encountered with updates and conversions have been summarized.Some proposals have been made for the application to over own drilling rigs.

半潜式钻井平台是深海油气资源开发的重要装备之一.半潜式钻井平台结构复杂,在设计建造及服役过程中,往往需要根据实际需求对平台原方案进行改造升级,而升级后平台的运动性能将与原平台存在一定差异,此时需要进行对比分析以确定升级方案的可行性.本文采用Sesam软件对某半潜式钻井平台改造后方案与其原方案的运动性能进行分析和对比.计算结果显示,与原方案相比改造方案的垂荡运动RAO第一峰值略增大、横纵摇值基本一致,平台总体水动力荷载变大.

应急解脱系统是深水水下防喷器组控制系统的重要组成部分,关系到深水钻井的安全.以南海某深水钻井平台的深水防喷器组应急解脱系统为例,利用其设备参数及现场反馈的数据作为输入参数,针对应急解脱不同工况下的操作要求,模拟计算了防喷器组进行作业时的动作时间、压力变化以及水下蓄能器组的压力和容积变化等.模拟分析方法及过程对于今后水下防喷器组性能评估具有重要的参考价值.

The semi submersible drilling platform plays an important role in the develop ment of the deepwater oil resources.When the platforms carried different quantity of mooring chains,the loading conditions may be changed which might affect its motion performance.The hydrodynamic software Sesam was used to analyze the motion performance of a semi-submersible drilling unit carrying different quantity of mooring chains.The results show that the variation of mooring chains makes little influence on the motion amplitude,accelerations and air gap of the platform. The research results may provide good proposal to the design of a new platform.

介绍深水半潜式钻井平台中控系统的组成,包括动力定位控制系统、全船监测报警系统及安全系统三部分.三大类分系统独立设计,各分系统又可细分为若干子系统,通过网络实现数据交换.阐述分析中控系统整体网络架构及三大类分系统的作用原理,并归纳总结各子系统及其相关设备的监测控制功能.

Several new mooring systems apply to deepwater environment are described in this paper,and the development status and the main manufacturer of the key equipments like anchor windlass,the mooring cables and the anchor foundations at home and abroad are also included here.This work can provide reference for the independent design and research of the mooring system in deep water.

Abstract The Liwan 3–1 gas field, situates in block 29/26 with an average water depth of 1,300m, represents the first major deepwater discovery in the South China Sea. The development scenario of Liwan 3–1 indicates potentially an efficient way for those gas fields around the continental slope of South China Sea. Before the first appraisal well being drilled, CNOOC Research Institute was commissioned to carry out Liwan 3–1 feasibility study on December 27, 2007. This paper provides an overview of several development scenarios based on the limited data of Liwan 3–1 such as wells information and assumed data such as reservoir profile and pressure. In view of those potential discoveries near Liwan field, regional development strategy is also taken into consideration. As a result, the suggested development scenario is subsea wells tieback to Boosting and Processing Center (BPC). Through BPC, the natural gas is processed and boosted via shallow water pipeline to onshore terminal plant. BPC is actually not only a feasible scenario to speed up Liwan 3–1 development, but also a regional solution for potential fields near Liwan 3–1. Introduction The Liwan 3–1 gas field is the first discovery in the deepwater of South China Sea and shared by CNOOC and Husky. Liwan 3–1 locates at a water depth of nearly 1500m and about 65km from PY30-1–1. The discovery of Liwan 3–1–1 well in 2006 showed that the gas production rate almost reaching 5 billion m3/a. Two appraised wells named Liwan 3–1–2 and Liwan 3–1–3 were also completed in the end of 2008 and in the middle of 2009 by West Hercules semisubmersible drilling platform respectively followed by another appraised well later. In this paper, several development scenarios of Liwan 3–1 gas field are demonstrated firstly. Then the scenarios of BPC (Boosting and Processing Center) are also studied based on a regional development view of potential fields near Liwan 3–1 and the scenario of one APP (accommodation and power platform) plus two PCPs (processing and compressing platform) is recommended. In view of minimizing investment and adopting regional development scenario, subsea wells tieback to BPC is suggested for the development of Liwan 3–1.

Developing deepwater oil and gas resource is the trend of oil industry development. It is important to select a proper development scenario and riser system which works as a key tool to connect subsea equipment and surface body in a deepwater project. Based on the West Africa’s deepwater target field CNOOC owned, this paper designs a detailed development scenario-FPSO +SPS +Shuttle tanker according to the following factors: well, reservoir layout, environment, floaters availability, commercial considerations. Floater and riser selection interact with each other. Considering the development scenario, a basic method for selecting a proper riser system is presented. As a result, FSHR is selected from existing risers based on technology, reliability, risk and cost.

The semi submersible drilling platform plays an important role in the development of the deepwater oil resources.For the demand of the short distance translocation in an oil field,the deep draught towing maybe encountered.Under this condition,the whole pontoons and the braces,part of the cylinders submerged in the water which caused towage resistance,the resistance of the braces toke part of 25% of the whole resistance.When the design plan was finalized,the main dimension and the distance of the braces were fixed,the towage resistance mainly caused by the shape of the cross section.Thus the software Fluent was used here to compute the drag resistance of a brace in a uniform viscous flow with different fillet radius,the regulation on the changes to the resistance was analyzed,also the a rational range of the fillet radius was got.According to the computation,the drag resistance coefficient of the brace with a fillet radius more than 0.3m will be reduced more than 60%.The research results may provide good proposal to the design of a new platform.

The problem of the uniform viscous flow around a forced oscillating vertical mounted circular cylinder is considered.Based on the incompressible Navier-Stokes equation,with the oscillating frequency equal to the period of the wake of the vortex,both the finite volume method and the PISO algorithm were employed for the numerically simulation.Some comparison to the force coefficient and fluid was made between the static cylinder and the forced oscillating cylinder.A sets of Reynolds number were taken to get the rule of the change of the force coefficient and the fluid around the cylinder.

An experiment is carried out in a flow experiment rig of deepwater freestanding riser system to simulate severe slugging elimination by gas-lift.It is found that injecting gas at the base of the riser can reduce the area of unstable flow on the flow regime map and the pressure and pressure fluctuation in the riser system,but excessive gas injection will increase the friction loss of flexible pipe and the pressure of the whole riser system,causing negative production.According to the change trend of pressure of the system with the flow rate of injected gas,the gas-lift control process of the freestanding riser system is divided into four stages with different flow patterns in the vertical rise.Gas-lift cannot eliminate the unstable flow in the freestanding riser system completely,but can control the flow pattern in the vertical riser at the boundary of hydrodynamic slug flow and transition flow to attain the best flow control performance.

The semi submersible drilling platform plays an important role in the development of the deepwater oil resources.For the demand of the short distance translocation in an oil field,the deep draft towing maybe encountered.Under this condition,the whole pontoons and the braces,part of the cylinders submerged in the water which caused towage resistance,but there was no empirical data to consult.Thus the software FLUENT was used here to compute the drag resistance of the platform in a uniform viscous flow with deep draft,and the comparison was made to the one with a shallow draft.According to the results,under the speed of 2 m/s,the drag resistance of the pontoons took about 50% of the whole,while the braces and the cylinders took around 25% each,the resistance with a deep draft was twice the one with shallow draft.The research results may provide good proposal to the design of a new platform.

The layout of cluster manifolds in the subsea production system mainly affects the efficiency, safety and cost of deepwater oil and gas fields. For constructing an optimal layout of cluster manifolds, subsea wells shall be first allocated to different well sets, and then, for each well set, a cluster manifold is mounted at a suitable location and connected with all subsea wells in the same well set. The subsea wells partition is a fundamental work for constructing an optimal layout of cluster manifolds. In this paper, a mathematical model of partition of subsea wells is developed, and its algorithm is also correspondingly proposed and programmed by MATLAB. Numerical analysis is performed and discussed for a specific case of subsea wells partition to verify the model's accuracy and the algorithm's feasibility. The results show that the mathematical model is appropriate for describing the partition problem, and the algorithm is efficient for the mathematical model. The connection cost between subsea wells and cluster manifolds can be thus decreased as greatly as possible. Compared with the traditional experience, it avoids the negative effects of human factors, and provides a more scientific and quantitative means for the layout of subsea production system. (C) 2012 Elsevier Ltd. All rights reserved.