In 2024

adhering to the "above-source

within-source

below-source" multi-layer three-dimensional exploration approach

PetroChina Tuha Oilfield Company deployed Well Jifu3 in Jinan sag of southeastern Junggar Basin. Drill-stem testing of the Upper Permian Wutonggou Formation yielded a high industrial oil flow of 96.3 t/d in Well Jifu3

marking a significant exploration breakthrough of oil reservoirs above the Permian Lucaogou F

ormation source rock. Based on integrated outcrop

drilling

logging

seismic

and analytical test data

a comprehensive study was performed on the structures

source rocks

and sedimentary reservoir characteristics of Wutonggou Formation oil reservoir in Jinan sag. The findings indicate that Jinan sag underwent four intense tectonic episodes during the Hercynian

Indosinian

Yanshanian

and Himalayan periods. The Yanshanian period

marked by intense oscillatory compression

constituted a critical phase in establishing the structural framework of Jinan sag. The source rocks of Lucaogou Formation are of good to excellent grades in quality

in the low-maturity to maturity stage

mainly generating oil

providing the main oil source for Jinan sag. The organic matter types and abundances of source rocks in Jinan sag are superior to those in Jimusaer sag. Wutonggou Formation develops a large braided river delta sedimentary system

where reservoirs are characterized by moderate porosity and low permeability. The primary reservoir spaces are residual intergranular pores and dissolution pores

and microfractures are relatively developed in Wutonggou Formation. Wutonggou Formation reservoir in Well Jifu3 is a structural-lithologic composite sandstone reservoir characterized by "lateral oil-generation and adjacent oil-accumulation". As controlled by source rocks

transport systems

and cap rocks

Wutonggou Formation reservoirs contains two major favorable zones in Jinan sag and the Santai uplift. The favorable zone in Jinan sag covers an exploration extent of 318 km

2

representing a realistic target for significant reserve growth. The prospective zone in Santai uplift spans 212 km

2

indicating significant potential for large-scale reserve expansion. This research provides a theoretical foundation for the next phase of efficient exploration in the Bogeda Mountain front of Junggar Basin

and also offers valuable insights for oil and gas exploration in similar regions at home and abroad.