The results of annual effective dose rate of radiation (ED_m ) and excess lifetime cancer risk (ELCR) have been computed based on the radiation exposure rates (RE_m ) measured using Model 3A- Ludlum radiation survey meter. This study was carried out within some selected Shell Petroleum Development Company of Nigeria operational locations in the Niger Delta Region of Nigeria. RE_m results ranged from 0.015±0.002 to 0.033±0.004 mR/hr with a mean of 0.023±0.003 mR/hr. These results are high relative to the standard external radiation level of 0.011 mR/hr set by the United States Nuclear Regulatory Commission.ED_m results ranged from 1.46±0.175 mSv/yr to 2.92±0.350 mSv/yr and are greater than the permissible dose limit of 1 mSv/yr set by the International Commission on Radiological Protection. Results of ELCR ranged between 4.59 x 10^-3 and 10.22 x 10^-3 and are high when compared with the world average value of 0.29 x 10^-3 . All these results were pictorially presented using geographical- location- based 3-D contour maps. Efforts should be made by concerned personnel and authorities to avert undue disposal of Naturally Occurring Radioactive Materials (NORM) into oil producing environments through production activities in order to forestall radiation health related impacts