Three successful large-scale field tests of crosshole electromagnetic tomography technology

摘要

A leading edge for the applied technological development of geophysics today - crosshole electromagnetic (EM) tomography technology, is an extremely challenging research topic. Its principal technological objective is to realize the direct measurement of the interwell resistivity in order to offer a two-dimensional, even three-dimensional resistivity image reflecting formation structure, reservoir property and the distribution of oil, gas and water between wells. So it not only is a momentous development of the conventional logging technology, but also will revolutionize the reservoir research. Shengli Oilfield (or SPAB) has cooperated with EMI to conduct the application study of the crosshole EM tomogrpahy technology for many years. Recently five large-scale industrial rests of the crosshole electromagnetic tomography were conducted successfully in three pairs of wells in Gudao and Chengdong oilfields attached to Shengli Oilfield. the desired results are achieved in three tests. Not only the stabiity and reliability of the instrument performance are proven, but also it is the first time in the world that a complete measurement dat awith good repeatability and high accuracy has been obtained when the interwell distance is up to 433.6 m for openhole to openhole and 147.19 m for openhole to steel-cased hole. The resistivity image obtained form the inversion has provided a good geological result in analyzing the interwell hydrocarbon and sand body distribution. These achievements indicate that great progress has been made in the industrialization of the crosshole EM tomography technology.