OIL AND GAS EXPLORATION PROSPECT OF HONGMIAOZI FAULT DEPRESSION IN THE SOUTHEASTERN PERIPHERY OF SONGLIAO BASIN: A Case Study of Lower Cretaceous Yingzuilazi Formation in LXD1 well

Hongmiaozi fault depression, located in northern Huanren Basin, is a half-graben depression faulted in the east and overlapped in the west. The outcrops and limited drilling work reveal a favorable condition for the formation of source rocks. Based on the drilling data from LXD1 well in the western fault depression, the study analyzes the oil-gas geological conditions and accumulation prospect of Yingzuilazi Formation. Test analysis shows that there is good oil-gas indication in Yingzuilazi Formation, with the source rocks dominated by semi-lacustrine grayish black mudstone, high abundance of organic matter, and the main body of organic matter in mature hydrocarbon generation stage, belonging to medium-good source rocks. Although the reservoirs are mainly of ultra-low porosity and low permeability type, the andesitic volcanic rock formation reservoirs are developed in both the overlying Linzitou Formation and underlying Guosong Formation, which provide multiple reservoir spaces for the formation of oil-gas reservoirs. Besides, the electrical exploration comprehensive interpretation section shows that the Yingzuilazi Formation with developed source rocks is sandwiched between the two volcanic formation reservoirs of Linzitou Formation and Guosong Formation, and directly contacted with the volcanic reservoir roof of Guosong Formation, forming a favorable source-reservoir-cap combination. It is inferred that Hongmiaozi fault depression has a good prospect of oil and gas exploration.