顺托果勒区块志留系水平井造斜段力化耦合井壁稳定研究
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摘要
根据地质构造特点及实际生产需要,顺托果勒区块非常适合布置水平井,尤其在造斜段钻进时以斜井弱面理论为基础的坍塌压力计算结果显示井壁稳定性良好,但现场复杂情况统计结果表明,水基、油基钻井液条件下,该区块水平井造斜段均出现大面积垮塌、阻卡掉块严重的情况,平均扩径率高达26.96%,严重影响钻井周期。为寻找解决途径,从该区块水平井造斜段I/S混层占优的地层岩性特点出发,从根本上抑制水化膨胀带来的附加作用,建立标准膨胀率-活度曲线,标定钻井液活度窗口,在钻井液活度窗口的限定下,使井壁稳定问题重新回到斜井弱面理论上来。结果表明在考虑了钻井液活度窗口的情况下,该区块新钻水平井造斜段扩径率降低85.69%,井壁稳定得到保障。
According to geological structure features and the demand of actual production,horizontal wells were very suitable to place in Shuntuoguole block,especially when drilling in the building section,the result of collapse pressure based on the weak planes theory in deviated well showed a nice wellbore stability. While statistical results of the complex cases in the field showed that severe collapsing and breakout existed in building section,under the conditions of applying water-base or oil-base drilling fluid,and the average expansion rate is up to 26. 96%,which had a serious impact on the drilling cycle. To solve the problem,based on the formation character that I / S mixedlayer had a dominant content in building section of horizontal wells from the block,to inhibit the additional effect caused by hydrate expansion fundamentally,the standard swelling rate-activity curve was established. The curve helped to standardize the activity window of drilling fluid,which could lead the problem of wellbore stability to back to the field of the weak planes theory in deviated well. The results showed that when considering the activity window of drilling fluid,the well expansion rate in building section of a newly drilled horizontal well from the same block had been reduced by 85. 69%,and the wellbore stability was guaranteed.
According to geological structure features and the demand of actual production,horizontal wells were very suitable to place in Shuntuoguole block,especially when drilling in the building section,the result of collapse pressure based on the weak planes theory in deviated well showed a nice wellbore stability. While statistical results of the complex cases in the field showed that severe collapsing and breakout existed in building section,under the conditions of applying water-base or oil-base drilling fluid,and the average expansion rate is up to 26. 96%,which had a serious impact on the drilling cycle. To solve the problem,based on the formation character that I / S mixedlayer had a dominant content in building section of horizontal wells from the block,to inhibit the additional effect caused by hydrate expansion fundamentally,the standard swelling rate-activity curve was established. The curve helped to standardize the activity window of drilling fluid,which could lead the problem of wellbore stability to back to the field of the weak planes theory in deviated well. The results showed that when considering the activity window of drilling fluid,the well expansion rate in building section of a newly drilled horizontal well from the same block had been reduced by 85. 69%,and the wellbore stability was guaranteed.
引文
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2 金衍,陈勉,柳贡慧,等.大位移井的井壁稳定力学分析.地质力学学报,1999;5(1):4—11
3 陈勉,金衍,张广清.石油工程岩石力学.北京:科学出版社,2008
4 鄢捷年.钻井液工艺学.北京:中国石油大学出版社,2006
5 天津大学物理化学教研室.物理化学(下册).北京:高等教育出版社,2001
6 柯仁楷,黄兴海.平衡相对湿度ERH原理在水分活度测量中的应用.中国食品添加剂,2005;(6):119—122
7 李健鹰.泥浆胶体化学.山东:石油大学出版社,1988
8 温航,陈勉,金衍,等.钻井液活度对硬脆性页岩破坏机理的实验研究.石油钻采工艺,2014;36(1):57—60
9 姜启源.数学模型.北京:高等教育出版社,2003