摘要
深水低温天然气水合物地层固井,需要水泥浆体系在水化过程中少发热,尽量降低水合物地层温度上升的程度。因此,针对深水天然气水合物地层固井,研究了一种用于低热水泥浆体系设计的新型相变材料,并研究了相变材料的热存储性能及其对水泥浆体系性能的影响。实验结果表明,新型相变材料相变峰值温度为15.5℃,相变温度在井下低温与常温之间,且相变潜热较大。当相变材料在77.8℃以下时,具有良好的热稳定性,且在0℃～60℃之间经历多次升降温后,相变材料化学结构没有发生变化。随着相变材料加量的增加,水泥浆的流变数据呈现增大的趋势,但加量达到8%时流变性依然满足固井施工要求。此外,新型相变材料可以改善水泥浆体系的稳定性。相变材料对低热水泥浆体系的抗压强度影响不大,加入8%相变材料的水泥石抗压强度也达到8.9 MPa,抗压强度最大下降幅度小于5%。当加入2%、4%、6%、8%相变材料后,水泥浆体系稠化时间比无相变材料水泥浆体系最大缩短约15 min,水泥浆体系72 h水化热较空白水泥浆体系分别下降5.2%、29.1%、35.6%、47.6%。研究结果为天然气水合物层低热水泥浆体系的设计提供了支持与参考。
When cementing wells drilled in low temperature deep water zones,cement slurry should give off less heat during hydration process to minimize the increase of temperature of the formations with natural gas hydrate.A new phase change material has been developed for use in low heat cement slurries used to cement wells penetrating formations with gas hydrate.The heat storage performance of the phase change material and its effects on the properties of cement slurry were studied.Laboratory experimental results showed that the peak temperature at which phase change takes place was 15.5℃for the new phase change material.This temperature sits between downhole low temperatures and ambient temperature,and the latent heat of phase change was high.At temperatures below 77.8℃,the phase change material had good thermal stability.No change to the chemical structure of the phase change material ever happened after the phase change material had undergone many times of temperature fluctuation between 0℃and 60℃.The rheology of the cement slurry increased with an increase in the concentration of the phase change material.Increasing the concentration of the phase change material to 8%did not affect the ability of the cement slurry to satisfy the needs of well cementing.Furthermore,the new phase change material helped improve the stability of cement slurry and only slightly affected the compressive strength of the low heat cement slurries.A low heat cement slurry treated with 8%of the new phase change material had set cement with compressive strength of 8.9 MPa,and the decrease of the compressive strength was less than 5%at most.When added 2%,4%,6%and 8%new phase change material into a cement slurry respectively,the thickening time of the cement slurry was 15 min less than that of the cement slurry without the new phase change material(the blank cement slurry).The 72-hour heat of hydration of the four cement slurries were reduced by 5.2%,29.1%,35.6%and 47.6%than the blank cement slurry,respectively.This study has provided a technical support and reference to the design of low heat cement slurry for use in cementing wells penetrating formations with natural gas hydrate.
作者
宋建建
许明标
王晓亮
黄峰
秦国川
SONG Jianjian;XU Mingbiao;WANG Xiaoliang;HUANG Feng;QIN Guochuan(Petroleum Engineering College,Yangtze University,Wuhan 430100;Hubei Cooperative Innovation Center of Unconventional Oil and Gas,Yangtze University,Wuhan 430100)
出处
《钻井液与完井液》
CAS
北大核心
2019年第2期218-223,共6页
Drilling Fluid & Completion Fluid
基金
国家科技重大专项课题"海外复杂地层固井及修井液技术"(2017ZX05032004-004)
关键词
低热水泥
固井
相变材料
水化热
天然气水合物层
Low heat cement slurry
Well cementing
Phase change material
Heat of hydration
Formation with natural gas hydrate
作者简介
第一作者:宋建建,博士研究生。现主要从事油井水泥外加材料研究工作。E-mail:songjian629@163.com;通讯作者:许明标,E-mail:xumingbiao@yangtzeu.edu.cn.
