The small-diameter oil and gas geology survey well, when used as a geological survey method, faces a lot of problems and difficulties in the drilling process. Based on the completed Well Yang D1, Well Heifudi-1, and Well Heifudi-2, the drilling characteristics, requirements and difficulty in the oil and gas geological survey well are analyzed. The risks in oil and gas geological survey drilling and the impact on evaluation of the oil and gas occurrence due to incomplete drilling equipment, drilling processes and related safety regulations are explained.