基于随钻前视探测技术的异常高压气层综合识别方法  

An integrated identification approach of abnormally high-pressure gas zones based on the look-ahead while drilling technology

作　　者：高永德 王世越 常波涛 孙殿强 陈鸣 王超 张磊 GAO Yongde;WANG Shiyue;CHANG Botao;SUN Dianqiang;CHEN Ming;WANG Chao;ZHANG Lei(CNOOC China Limited Zhanjiang Company,Zhanjiang,Guangdong 524057,China;CNOOC China Limited Hainan Company,Haikou,Hainan 570300,China;Schlumberger China,Beijing 100016,China)

机构地区：[1]中海石油(中国)有限公司湛江分公司 [2]中海石油(中国)有限公司海南分公司 [3]斯伦贝谢(中国)公司

出　　处：《天然气工业》2022年第10期98-106,共9页Natural Gas Industry

基　　金：中海石油(中国)有限公司科技项目“钻头前地层压力随钻预测方法研究”(编号:ZYKY-2020-ZJ-03)。

摘　　要：南海北部乐东地区是莺歌海盆地高温高压天然气勘探开发的重点地区,但钻井作业采用的不同探测技术受到测量深度、垂向分辨率和预测精度等影响,难以保障安全钻井需要及时预警和规避高压层的孔隙压力和界面深度的需求。为此,通过综合基于常规随钻测井资料的压力监测技术、基于垂直地震剖面(VSP)资料的钻头前方地层界面及压力预测技术和IriSphere随钻前视探测技术的特点,提出了以IriSphere随钻前视探测技术为主导的综合预测方法并进行了现场应用。研究结果表明,(1)钻前模拟显示,当轨迹在低阻泥岩层中,可提前8~10 m探测到较高阻、且较厚(厚度大于3 m)的高压气层,前视探测技术在实钻中有较大可能实现预期的前视效果;(2)通过结合分辨率较低、探测深度深的VSP预测和分辨率较高、探测深度浅的随钻前视探测方法进行随钻决策,识别出了钻头前方的高压气层及其对应的地层孔隙压力增加趋势;(3) VSP法预测的钻头前方高压气层顶界深度与实钻深度误差介于-10~33 m,而随钻前视探测较高阻、厚度5 m的高压气层,预测深度仅与实际深度相差1 m。结论认为,经过现场应用实践该综合识别方法能及时有效地预防高压气层相关的地质工程风险,准确定位套管鞋深度位置,为莺歌海盆地中深层高温高压天然气的高效勘探开发提供了技术保障。The Ledong area of the northern South China Sea is an important exploration and development area of high-temperature and high-pressure(HTHP) natural gas in the Yinggehai Basin.Due to the influence of measurement depth,vertical resolution and prediction accuracy,the detection technologies adopted in drilling operation can hardly meet the requirements of timely warning for safe drilling and evading from pore pressure and interface depth of high-pressure zone.To solve this problem,this paper proposes an integrated prediction approach dominated by IriSphere look-ahead while drilling technology by integrating the advantages of the pressure monitoring technology based on conventional logging while drilling data,the ahead-of-bit formation boundary and pressure prediction technology based on vertical seismic profile(VSP) and the IriSphere look-ahead while drilling technology.In addition,the integrated prediction approach is applied on site.And the following research results are obtained.First,predrill modeling shows that when the well trajectory is in a low-resistivity shale zone,it can predict the high-pressure gas zone of higher resistivity and greater thickness(>3 m) by 8 to 10m ahead.It is more possible that the look-ahead technology can achieve the expectation in actual drilling operation.Second,when the low-resolution and deep-DOI(depth of investigation) VSP prediction and the high-resolution and shallow-DOI look-ahead while drilling technology are combined for decision making while drilling,the high-pressure gas zone ahead of the bit and the rising trend of the corresponding formation pore pressure can be identified.Third,the error between the top depth of the high-pressure gas zone ahead of bit predicted by VSP and the actual depth is between-10 m and 33 m,while for the high-pressure gas zone which has higher resistivity and thickness of 5 m,the error between the prediction by look-ahead while drilling technology and the actual depth is only 1 m.In conclusion,field application practices show that this integrated

关 键 词：高压气层 综合识别方法 随钻前视探测技术 井身结构 孔隙压力预测 垂直地震剖面 

分 类 号：P618.13[天文地球—矿床学]