APPLICATION OF NEUTRON GAMMA LOGGING IN SEARCHING FOR REMAINING GAS RESERVES IN THE LIAOHE BASIN

Most of the fault-block reservoirs in the Liaohe Basin have been in the middle-late stage of development. The production of these gas reservoirs dose not conform to the standard, due to the constraint of various factors at the initial stage of exploration and development. The medium-deep gas reservoirs are associated with the development of the oil reservoirs, and the shallow gas reservoirs are produced by a few gas wells, increasing the difficulty of searching for the remaining gas. Search of the remaining gas reserves should begin with the review of the geological information of oil and gas reservoirs, and integrate the neutron gamma logging data with the analysis of the gas reservoir production, so as to obtain the hydrogen contents of the sand reservoirs saturated with oil, gas, or water. A discrimination criteria searching for remaining gas is that the hydrogen content of sand reservoirs saturated with oil or water is much higher than that of sand reservoirs saturated with gas. Moreover, attentions should be paid to the influences of the fundamental factors, such as porosity, gas saturation, shale content, casing size, and killing fluid. Production practice shows that this is a new concept to develop the remaining gas reserves and is worthy of popularization and application.