低渗透油藏薄差油水层解释方法研究

Interpretation method for the thin-poor oil-water layers in the low-permeability oil reservoir

针对松辽盆地太东油田葡萄花低渗透油藏薄差油水层较多、流体识别较困难而造成的解释精度偏低的问题,在分析研究多口井资料的基础上,发现主要因素是高电阻率水层、低电阻率油层、残余油的存在以及解释图板误差较大等问题。测井曲线由于受储集层岩性、物性、厚度等因素影响,出现了高电阻率水层和低电阻率油层;加之断层的切割作用,使油气发生二次运移,在毛管张力的作用下,油气运移不彻底,导致残余油的存在。通过编制精细解释图板和储集层流体判别模型,加测碳氧比能谱测井等手段,总结出太东油田薄差层流体识别的有效方法。在多口井应用中见到较好的效果,使解释符合率稳中有升,不仅为外围油田新区钻井运行及射孔方案编制提供了较为准确的基础数据,而且对于现场录井工作也具有指导意义。

In view of the problem of many thin and poor oil-water layers existing in low permeability oil reservoir, and the fluid being difficultly identified, and thus the interpretation accuracy being lower for Putaohua low permeability oil reservoir of Taidong oilfield in Songliao Basin, and on the basis of studying many wells′data, the authors found out that the main resulting factors were high-resistivity water layers, low-resistivity oil layers, residual oil occurrence, and the bigger interpretation chart error and so on. Affected by reservoir lithology, physical property, thickness and other factors, well logging curves occurred high-resistivity water layers and low-resistivity oil layers, and under the function of fault cutting, the oil and gas existed in secondary migration, but capillary tension made oil and gas migrated not thoroughly, thus leading the occurrence of the residual oil. Through the means of establishing fine interpretation chart and reservoir fluid discriminant model and increasing C/O ratio spectrometry logging and so on, the paper summed out the available fluid identifying methods for the thin-poor layers of Taidong oilfield. Through the application in many wells, these methods showed the better results and made the interpretation coincidence rate go up steadily, which not only provided the more accurate basis data for drilling new areas in outer-laying oilfields and compiling the perforation plan, but also had the guiding significance to mud logging on the well site.