渤海油田腐蚀磨损套管剩余强度计算  

Calculation of Residual Strength of Corroded and Worn Casing in Bohai Oilfield

作　　者：李文涛 LI Wen-tao(CNOOC Safety Technology Service Co.,Ltd.Tianjin 300457,China)

机构地区：[1]中海油安全技术服务有限公司,天津300457

出　　处：《全面腐蚀控制》2024年第3期130-135,共6页Total Corrosion Control

摘　　要：对渤海油田油气井的完整性问题详细排查,发现存在环空异常带压占比较高,导致井筒服役安全面临巨大的挑战。为有效计算环空最大承压能力,控制环空压力在有效的安全范围,需更精确的核算套管的有效剩余强度。渤海油田油气井套管腐蚀以CO_(2)为主,本文综合考虑套管在磨损、CO_(2)腐蚀共同作用,基于利用符合海洋石油特点的“De.Warrd模型的腐蚀速率预测模型”、“长期腐蚀速率预测模型”以及“管柱强度计算模型”,建立了套管磨损、腐蚀后的剩余强度计算方法,以环空带压自喷井2D井为例,对套管剩余强度进行核算,结果表明,套管以腐蚀为主要因素,磨损发生在套管下深中部的情况下,对套管中部剩余强度有影响,对套管整体最小剩余强度几乎无影响。通过该方法在核算套管在磨损及腐蚀双重影响下的套管剩余强度有重要意义,有效指导安全生产。A detailed investigation of the integrity issues of oil and gas wells in Bohai Oilfield revealed that there is a high proportion of abnormal annular pressure,which poses a huge challenge to the safety of wellbore service.To effectively calculate the maximum bearing capacity of the annulus and control the annulus pressure within an effective safety range,it is necessary to more accurately calculate the effective residual strength of the casing.The corrosion of casing in oil and gas wells in Bohai Oilfield is mainly caused by CO_2.This article comprehensively considers the combined effect of casing wear and CO_(2) corrosion.Based on the use of the “De.Ward model for corrosion rate prediction”,“long-term corrosion rate prediction model”,and “pipe string strength calculation model” that are in line with the characteristics of offshore oil,a calculation method for residual strength after casing wear and corrosion is established.Taking the 2D well with annular pressure self flowing well as an example,The calculation of the residual strength of the casing shows that corrosion is the main factor affecting the overall minimum residual strength of the casing.When wear occurs in the deep middle of the casing,it has an impact on the residual strength of the middle of the casing.This method is of great significance in calculating the residual strength of casing under the dual effects of wear and corrosion,and effectively guides safety production.

关 键 词：渤海油田 环空带压 套管磨损 套管腐蚀 套管剩余强度 

分 类 号：TE983[石油与天然气工程—石油机械设备]