玉北深层稠油储集层气测与岩石热解综合解释评价方法

Comprehensive interpretation and evaluation of gas logging and rock pyrolysis for deep heavy oil reservoirs in Yubei Block

吐哈盆地台南凹陷北部玉北区块深层二叠系稠油储集层气测录井异常显示微弱,呈C_1相对含量低、C_2相对含量较低和重组分含量高的特征,岩石热解分析以S_1、S_2峰为主,属于一种特殊烃组分的储集层,采用常规气测或岩石热解单一录井方法建立的图板难以有效识别流体性质。在分析该区块10口井15层试油层不同流体性质储集层气测与岩石热解录井参数特征的基础上,尝试应用气测与岩石热解各自常规图板类型统计分析,筛选出区分油层、差油层、干层明显的两个特征参数——C_1/C_3和P_g,建立了气测与岩石热解参数综合解释评价图板及标准,为该区块稠油储集层解释评价提供了有效方法。回判应用解释评价符合率为86.7%,2015年新井应用解释评价符合率为87.5%。虽然该方法解释评价符合率较高,但有时会出现油层与干层重叠的特殊情况,可结合录井的荧光分析、岩心观察以及测井资料,综合确定解释评价结论。

The gas logging abnormal shows are weak for heavy oil reservoirs in deep Permian,Yubei Block in Northern Tainan Sag of TuHa Basin,which presented the features of the low relative content of C_1,lower relative content of C_2 and high heavy components′ content.Rock pyrolysis analysis was dominated by S_1 and S_2peaks,it belongs to a special hydrocarbon component reservoir,and it is difficult to effectively identify fluid properties by using the charts that were set up by single mud logging method,such as conventional gas logging or rock pyrolysis.Based on the analysis of reservoir parameter features of gas logging and rock pyrolysis logging of the different fluid properties from 15 oil testing layers of 10 wells in the block,applying the conventional charts of gas logging and rock pyrolysis respectively to make statistical analysis,the authors selected two obvious characteristic parameters─C_1/C_3 and Pg,which can distinguish oil layers,poor oil layers and dry layers clearly,and establish the comprehensive interpretation and evaluation chart and criteria of gas logging and rock pyrolysis parameters,which provides an effective method for interpreting and evaluating heavy oil reservoirs in the area.The coincident rate of the interpretation and evaluation was 86.7%,the coincident rate for new well interpretation and evaluation in 2015 was 85.7%.Although the method has a higher interpretation and evaluation coincident rate,sometimes special cases may occur,for example,oil layers overlap dry layers,then the fluorescence analysis and core observation of mud logging can be combined with well logging data to comprehensively determine the interpretation and evaluation results.