古地磁岩芯定向法在榆树林油田储层天然裂缝定向中的应用

APPLICATION OF PALEOMAGNETIC COREORIENTATION TO NATURAL FRACTURE ORIENTATION OF RESER VOIR IN YUSHULIN OILFIELD

榆树林油田扶杨油层低孔渗砂岩储层由于受区内断层的影响，发育了较为丰富的天然裂缝，天然裂缝的存在改善了储层的储油物性，在油田开发过程中，天然裂缝对压裂效果和注水开发将产生显著影响。本区的天然裂缝以构造裂缝为主，多发育在砂岩和过渡岩性中。通过对发育有天然裂缝的岩芯剩余磁化矢量的测量，结合古地磁场的基本特征，用坐标变换的方法将岩芯裂缝进行了定向。结果表明，本区扶杨油层的天然裂缝延伸方向基本与区域断裂方向一致，以近南北向为主，从而实现了天然裂缝岩芯样品的古地磁定向。

Fuyang oil-bearing formation in Yushulin oilfield is a lower permeable sandstone reser-voir. There are a large number of natural fractures due to the faulting in this area,The nat-ural fractures have improved the permeability of sandstone and affected the formation frac-turing and water injection.Therefore,it is necessary to learn about the characteristics andextending directions of these natural fractures. The research shows that most natural frac-tures are structural fractures in this area.Thev are found in the sandstones and pelitic silt-stone. By measuring the remanent magnetic vectors of cores where there are natural frac-tures,and considering the elementary characteristics of paleomagnetic field, the cores areoriented by means of coordinate svstem transformation. The result is that the natural frac-tures in Fuyang oil formation mainly extend in roughly north- south direction,coincidingwith that of the regional fracture.