胜坨油田沙河街组二段复杂断块油藏水淹层测井解释研究

以胜坨油田发育的典型复杂断块油藏为例,利用密闭取芯井资料建立判别关系和测井解释模型,进行沙河街组二段1-3砂组复杂断块油藏水淹层测井解释。首先介绍了该水淹层测井响应特征,接着应用多项式趋势面分析方法对测井数据进行标准化处理,并选择测井资料齐全、质量可靠、有钻井取芯和录井、试油资料的井为关键井,结合试油试采、岩芯分析资料建立测井解释模型。结果表明:胜坨油田沙河街组二段1-3砂组复杂断块油藏已经进入高含水阶段,水淹层发生明显的自然电位曲线基线偏移、地层电阻率降低、自然伽马降低、声波时差增大等现象;选择沙二段顶部的高阻白云岩段(厚度为8～12m)作为标准层进行标准化处理;声波时差三次趋势面分析效果较好,拟合度达到22.6%,平均校正量为14μs/m;T4j17、T2-121井取芯井段较长且收获率较高,分析化验资料较丰富,测井资料齐全且质量较好,能够反映沙二段1-3砂组复杂断块油藏储层特征,被选为关键井;建立泥质体积分数、粒度中值、孔隙度、渗透率、含水饱和度等解释模型。最后,通过对水淹层的测井资料进行逐井处理、计算机逐点或按层输出主要储层参数等3个方面检验解释模型,定量评价了测井解释模型的应用效果。结果表明:测井解释结果与岩芯物性和生产数据吻合较好,获得了较为可靠的地区储层地质分析结果,可为注水开发调整提供有效的参考。

Study on Log Interpretation for Water Flooded Layer of the Complex Fault Block Oil Reservoir in the Second Member of Shahejie Formation of Shengtuo Oilfield

Based on the data of sealed core well, taking the typical complex fault block reservoir in Shengtuo Oilfield as an example, log interpretation model was built to interpret the well logging for water flooded layer of the complex fault block oil reservoir in the 1-3 sandstone group of the Second Member of Shahejie Formation. Firstly, response characteristic of the water flooded layer was introduced; secondly, log data was standardized by the method of polynomial trend surface analysis; thirdly, the key well with complete log data, dependable quality, drilling core and logging, and test oil data was selected; fourthly, log interpretation model was built according to oil testing and extraction and drill core data. The results showed that the complex fault block oil reservoir in the 1-3 sandstone group of the Second Member of Shahejie Formation of Shengtuo Oilfield had been in the stage of high water cut, baseline of self potential curve shifted, formation resistivity and natural gamma decreased, and acoustic time increased in water flooded layer; high resistant dolomite segment(thickness was 8-12 m)in the top of the Second Member of Shahejie Formation was selected as a key bed for standardization; the method of cubic trend surface analysis for acoustic time was acceptable, the degree of fitting was 22.6%, the average correcting value was 14 μs/m; T4j17 and T2-121 were selected as key wells, in which core well section and recovery of core were optimal, and related data were abundant with high quality, to show the characteristics of the complex fault block oil reservoir in the 1-3 sandstone group of the Second Member of Shahejie Formation; the log interpretation models built were shale volume fraction, median size, porosity, permeability, water saturation, and so on. Finally, log interpretation data was used to export the main parameters by means of well-by-well, point-by-point and layer-by-layer, and verify the models, in order to evaluate the effect of log interpretation models. The results showed that compared with physical property of core and related observation, the simulation of log interpretation models had good agreement with the observed data, and could provide an effective reference for improving waterflood development.