摘要
地层压力随钻评价是关系石油勘探开发成效的重要课题,在物探、测井、录井等勘探技术领域已分别采用不同的方法进行了相关预测和分析研究,其中物探、测井的压力评价结果常常用于油气井地质、工程设计时的参考,而录井的随钻dc指数法等压力分析和预报多被用于修正钻井设计,实时指导工程施工,避免井喷、井漏等风险。但以往的技术方法一是未能将异常压力的成因分类与地层压力评价方法有机结合,二是偏重于地球物理的方法研究、忽视了工程录井及新技术方法的研究。为此,从指导实践出发,对地层压力成因进行了系统分类。归纳出异常高压10种,异常低压6种;分析了地层压力随钻评价理论是基于岩石物理和孔隙流体异常于正常压实.它在检测参数上具备响应特征.指出了不寻常自生矿物的出现也可作为超压层的标志,评价中结合异常压力成因的分析更有利于解释结果的科学性;将随钻评价方法归纳为工程录井法、地质统计分析法和新技术法,并提出了dc指数趋势线的变换原则.这是保障压力预测可靠性的基础。结合实例介绍了这些评价方法的有效性,强调在使用中注重方法组合,发挥不同方法的优势。实现不同压力成因条件下的准确评价。
Formation pressure evaluation while drilling is the ma- jor subject which has concern with the achievements in pe- troleum exploration and development,different methods have been individually adopted in the fields of exploration technologies of geophysical prospecting,wire line logging, mud logging.Among these technologies,the pressure eval- uation results got from geophysical prospecting wireline log- ging are commonly used as the references for oil and gas well geology and engineering design,while the results of pressure analysis and prediction taken from the method of dc index while drilling in mud logging are mostly used to a- mend drilling proposal,gearsteer drilling in real time,avoid the risks of blow out and lost circulation.Disadvantages of former techniques were that original classification of abnor- mal pressure couldn't be organically combined with forma- tion pressure evaluation methods,the geophysical method was particularly emphasized,and engineering logging and new technique wasn't paid enough attention to.Therefore, in order to direct practice,the authors classified the origins of formation pressures systematically,summarized 10 types of abnormal high pressure,6 types of abnormal low pres- sure,analyzed that the theory of formation pressure evalua- tion which was based on that the rock physics and pore fluid was abnormal with that of normal compaction and it pos- sessed corresponding features on parameter detection, pointed out that the occurrence of unusual authigenic miner- al can also be taken as the symbol of overpressure zones and the interpretation result was more scientific combined analy- sis of abnormal pressure origin.The paper summarized the evaluation methods while drilling as the method of engineer- ing logging,geologic statistic analysis and new technique, put forward the changing laws of dc index trend which was the base of ensuring the reliability of pressure prediction. Combined with real examples,the paper introduced the ef- fectiveness of these evaluation methods,emphasized the methods combination during application,bringing the ad- vantages of different methods into play and realizing the ac- curate appraisals under different pressures and origins.
出处
《录井工程》
2008年第4期12-16,共5页
Mud Logging Engineering
基金
国家重点基础研究发展计划(973计划)(2003CB214601)项目
关键词
地层压力
dc指数法
工程录井
随钻评价
孔隙体积
孔隙流体
方法组合
formation pressure
dc index method
engineering logging
evaluation while drilling
pore volume
pore fluid
method combination
