基于点源的救援井探测模型分析与仿真

Analysis and simulation of relief well detection model based on point source

钻救援井是目前控制井喷事故的有效方法。为了研究救援井电磁探测方法,采用井地电流注入法,构建了基于点源的救援井探测模型,并利用有限元软件,分析了电极布局方式、电流大小、事故井与电极间距、套管长度对事故井套管汇聚电流密度的影响。研究结果表明:接地电极置于套管处更利于事故井套管的电流汇聚;电极与套管的间距越大则汇聚电流密度越小,且注入电流大小与套管的汇聚电流密度大小呈线性关系;汇聚电流密度大小随套管长度的增加而增大,但增大的幅度随着套管长度的增加而减小。验证了事故井套管汇聚电流模型的有效性与可行性,为研制救援井连通测量工具提供了一定的理论依据。

Drilling relief well is an effective way to control blowout at present. To study electromagnetic detection for relief wells, by using well-ground current injection method, the relief well detection model based on point source has been built, fnite element software has been used to analyze impacts of electrode arrangement, current size, the distance between blowout well and electrode, and casing length on density of aggregation current on casing in the well with incident. The research results show installation of ground electrodes on casing may facilitate current aggregation on casing of well with incident; the longer the distance between electrode and casing, the lower the density of aggregation current will be, in addition, the in-fow current and density of aggregation current on casing are in linear relationship; density of aggregation current increases with increase of casing length, but amplitude of such increase decreases with the increase of casing length. Relevant researches have verifed effectiveness and applicability of the model for aggregation current on casing in wells with incident. The research results can provide a theoretical basis for developing tools detecting connectivity with the relief well.