石油学报 ›› 2011, Vol. 32 ›› Issue (6): 1042-1049.DOI: 10.7623/syxb201106018

• 石油工程 • 上一篇    下一篇

深水井控的七组分多相流动模型

孙宝江  王志远  公培斌  宋荣荣   

  1. 中国石油大学石油工程学院  山东东营 257061
  • 收稿日期:2011-04-30 修回日期:2011-08-04 出版日期:2011-11-25 发布日期:2012-01-17
  • 通讯作者: 孙宝江
  • 作者简介:孙宝江,男,1963年11月生, 1985年毕业于华东石油学院钻井工程专业,现为中国石油大学(华东)流体力学学科负责人、长江学者特聘教授、博士生导师,主要从事油气井工程、海洋石油工程、多相流理论及应用等方面的研究。
  • 基金资助:

    国家自然科学基金重点项目(No.51034007)、国家自然科学基金项目(No.50874116及No.51104172)、山东省自然科学基金(ZR2010EL010)和山东省博士后创新项目专项资金(200903107)联合资助。

Application of a seven-component multiphase flow model to deepwater well control

SUN Baojiang  WANG Zhiyuan  GONG Peibin  SONG Rongrong   

  • Received:2011-04-30 Revised:2011-08-04 Online:2011-11-25 Published:2012-01-17

摘要:

针对深水井控的特点,考虑深水钻井外部的多温度梯度环境和天然气水合物相变,将井筒内流体分为7种不同组分,建立了七组分井筒多相流控制方程。利用全尺寸实验井对井筒多相流动规律和井筒压力计算精度进行了验证。以墨西哥湾Mississippi Canyon井钻井工况为例,应用所建立的七组分多相流动模型算法,从溢流和井喷过程模拟、压井过程模拟及天然气水合物相变对井控参数影响等几个方面对深水井筒多相流动规律进行了分析。模拟发现,气体在沿井筒上升初期膨胀量比较小,进入隔水管内后开始明显膨胀,越靠近井口膨胀越剧烈。从溢流发展到井喷可分为3个阶段:井涌发展阶段、井喷阶段和井内喷空阶段。在井涌阶段末期,井底压力、泥浆池增量、隔水管内的气体体积分数等会发生剧烈变化,在极短的时间内演化为井喷。在深水压井过程中,由于节流管线内气体交换效应,节流压力的调节速度要高于陆地井控。由于水合物的生成,减小了泥浆池增量,降低了关井套压,给溢流的检测及气侵程度判断带来困难。

关键词: 深水, 井控, 七组分多相流动模型, 水合物, 井涌

Abstract:

In view of a multi-temperature gradient environment outside deepwater drilling wells and the phase transition of natural gas hydrates, the present paper divided the wellbore fluid into seven different components based on characteristics of deepwater well control and established a seven-component multiphase flow control equation. Multiphase flow experiments of wellbore were carried out on a full-scale test well and the calculation accuracy of wellbore pressure was verified. Taking a Mississippi Canyon drilling well status in the Gulf of Mexico as an example, we investigated multiphase flow rules of deepwater wellbore by applying the established seven-component multiphase flow model to simulate various processes including overflow, blowout and well killing as well as to evaluate effects of the gas hydrate phase transition on well control parameters. The simulation indicated that gas expansion was quite limited at the very beginning when gas rose along wellbore but it started to expand significantly after entering a riser, and the nearer to the well head the more intensive the gas expansion. The period from well kick to blowout could be divided into three stages: development of well kick, development of blowout and a stage of borehole with little mud. At the end of well kick, bottom hole pressure, pit gain and gas volume fractions within the riser would vary dramatically, which could turn into blowout in quite a short time. During well killing, the regulated speed of throttle pressure was faster in deepwater than that onshore due to the effect of gas exchange in a chock line. The formation of hydrate in annulus could result in the reduction of pit gain and the decrease of casing pressure shut in, which would affect the overflow detection and make it difficult to evaluate the extent of gas cut.

Key words: deepwater, well control, seven-component multiphase flow model, gas hydrate, well kick