Exploration progress of the Paleogene in Jiyang Depression,Bohai Bay Basin

With increased exploration in the faulted basins of eastern China,petroleum exploration in this region has been challenged by unclear remaining petroleum resources distribution,complex reservoir and hydrocarbon enrichment patterns,and lacking of suitable exploration techniques.Aiming at resolving these problems,studies on source rocks,reservoirs,hydrocarbon accumulation and geophysical prospection were carried out by laboratory analysis,reservoir anatomy,and seismic analysis.A highlyefficient hydrocarbon generation/expulsion model of source rocks in saline environment was established,which aided in the discovery of a new set of source rocks in the Jiyang Depression.This study also reveals the formation process of high-quality reservoir by alternating acid and alkaline fluids during deposition and diagenesis,and pattern of secondary pores development in deep clastic rocks.Through the fine anatomy of the oil reservoirs,an orderly distribution pattern of the oil reservoirs is established,and the potential exploration targets in the undrilled area are identified.In addition,single-point highdensity seismic acquisition and high-resolution imaging technologies are developed,enabling fine and efficient exploration in areas with high exploration maturity.The research result plays a leading and demonstrative role in the fine and efficient exploration of faulted basins in eastern China.

Reservoir formation conditions and key technologies for exploration and development in Shengtuo oilfield in Bohai Bay Basin

The Shengtuo oilfield is the largest monolithic oilfield in the Bohai Bay Basin and even in the continental fault basins of Eastern China.Since discovered in 1963,the Shengtuo oilfield experiences the early exploration stage of rapid reserve discovery and production,the middle exploration stage of high and stable production and development,and the late exploration stage of theoretical and technological innovation for expanding the field of exploration,research on fine development technology of high-water-cut reservoir for enhanced oil recovery,and maintaining slow decline of oil production.Re-serves of this oilfield increase in each stage.By the end of 2018,after more than 50 years of exploration and development,the Shengtuo oilfeld has cumulative proven oil reserves of 0.512 x 10°t,cumulative oil production of 0.193 x 109t,and it keeps stable annual production of more than 150 x 105t in 2018.Abundant hydrocarbon resources,large anticline structure near to oil source,multiple types of reservoirs and traps,and favorable hydrocarbon migration channels provide favorable hydrocarbon accumulation conditions for the Shengtuo oilfield.Fine development techniques such water-flooding in the early development stage,fine reservoir description in the high water cut stage,stratigraphic subdivision and well pattem vector adjustment,tapping remaining oil in rhythmic layers,etc,as well as conti nuous progress in exploration technologies of glutenite and turbidite reservoirs around the main body of the oilfield in the high-level exploration stage,provide effective supports for continuous increase of reserves and long-term high and stable production of the Shengtuo oilfeld.