A preliminary discussion on methodology to determine lower economic limit resources for offshore gas prospects;

Sub salt oil & gas structures are the main gas source for the project of “West—East Gas Transmission” engineering.

We find a kind of technique that could determine the depth of the water-bearing structure in the roof and floor of coal seam using the multi-frequency technique to calculate and to analyse some data got from a coal mine.

Via on-the-spot actual measurement, tracing survey and analyses on moisture curve, the orientation of water-bearing structure was accurately predicted, water disaster was avoided, the excavation of this orebody was accomplished faster, and great economic benifit was achieved.

Using the mine audio-frequency electrical penetration technology detects the coal floor water-bearing structure of the first fully mechanized mining face in Danhou mine,and which has provided the basis for the prevention and control of ordovician limestone water on mining face.

Based on an example of getting through water bearing structure,in the course of tunneling,this paper makes an analysis of the methods of getting through water bearing structure,and puts forward the ways to solve such kind problems which can be used for reference.