Abstract:

Secondary viscous remanence(low-temperature component) and primary remanence(high-temperature component) can be effectively separated by thermal-demagnetizing process. The orientation of the viscous remanence should be correspondent with that of available magnetic field, and the primary remanence should be consistent with the magnetic field orientation of then deposition of rocks. The original direction of drilling cores can be determined by vector compounds in line with above principle. The anisotropy of rock magnetic susceptibility, caused by the oriented arrangement of magnetic minerals effected by then magnetic field,reflects the feature of the rock magnetic fabric. The magnetic fabric shows mainly as the rock depositional fabric, therefore, environmental information of rock deposition can be gained and pale-current orientation and extension direction of sand body can be defined by studying the magnetic fabric. A research on the paleomagnetic orientation and magnetic fabric from recent drilling cores in Nanniwan oil field indicates that the extension direction of reservoir sand body in the area(namely, water flow direction) is near EW.

Key words: stagnant remanence, primary remanence, magnetic fabric, vetor composition, sandbody extension, Nanniwan oil field