METHOD STABILITY AND ANOMALY REPRIDUCIBILITY ANALYSIS IN SURFACE GEOCHEMICAL EXPLORATION FOR OIL AND GAS-A CASE STUDY OF THE SHIWU FAULT DEPRESSION IN SONGLIAO BASIN

Based on the results of repetitive tests above the existing oil and gas fields in Shiwu fault depression in southeastern uplifted area in Songliao Basin,the method-stability of acid-digestion hydrocarbon,heat-release hydrocarbon,headspace gas and ΔC and reproducibility of the anomalies determined by these indicators are discussed.The results showed that the concentrations of the geochemical indicators in repetitive tests had stability to a certain extent.And in special distribution,the anomalous zones defined by the geochemical indicators in repetitive tests had reproducible features.The medium-value and high-value anomalies of the indicators had better reproducibility above oil and gas fields.The concentrations of the indicators in background areas were lower.