Evaluation Of Paleogene Oil And Gas Resources Potential In Liaodong Bay Area

Liaodong Bay area is an important oil and gas production area in Bohai Bay Basin,geologists have evaluated oil and gas resources potential several times,but there are still some problems need to be solved: the oil and gas resources potential of deep source rock have not been evaluated,the latest seismic interpretation data have not been applied in the study,the potential of hydrocarbon generation and expulsion in every sub-segs and every formations have not been researched,the evaluation units have been divided roughly,which influence the determination of the exploration areas.Therefore,we used the basin simulation method and the research results of the hydrocarbon generation and expulsion characteristics of source rocks to evaluate oil and gas resources potential,tested the rationality of the simulation results,forecasted the favorable oil and gas contributing region and oil and gas gathering zone,and defined the exploration direction.We selected the basic parameters and maps that used to simulate reasonably,used PetroMod software to simulate,and obtained the amount of hydrocarbon generated of source rocks in every sub-segs and every formations at different critical times.Based on the oil and gas generation rate obtained by simulation experiment of hydrocarbon source rock samples in this study area,we combined the change characteristics of porosity and oil saturation to calculate the rate of the hydrocarbon expulsion in different TOC and maturity.Based on the results of the evaluation of the source rock,we calculated the oil and gas expulsion amount of source rocks in every sub-segs and every formations.The analogy method was used to determine hydrocarbon accumulation factor based on reasonable selection of calibration area and the control factors of oil and gas accumulation,and we also combined with the research results of the hydrocarbon generation and expulsion characteristics of source rocks to forecast the resources of Palaeogene source rocks.According to the study,the total amount of hydrocarbon generared in Liaodong Bay area are about 33.87 billion tons,the oil generation amount are about 28.43 billion tons,the gas generation amount are about 6.83 trillion cubic meters.The Shasan Formation source rock has the largest hydrocarbon generation amount with 15.54 billion tons,accounting for 45.9% of the total hydrocarbon generation amount;the north sag in Liaozhong Depression is the main hydrocarbon contributing region,the hydrocarbon generation amount are about 13.79 billion tons.The oil expulsion amount of source rocks are about 13.65 billion tons,the average efficiency of oil expulsion is about 48%;the gas expulsion amount of source rocks are about 4.63 trillion cubic meters,the average efficiency of gas expulsion is about 68%.The resources of Palaeogene source rocks in Liaodong Bay area are 3.2 billion tons,the oil and gas resource in Liaoxi Uplift are 1.58 billion tons,the oil and gas resource in Liaodong Uplift are 1.13 billion tons,this two uplifts are the main oil and gas gathering zone and the favorable exploration area.Compared with previous studies,this paper used the latest data to solve the problem of hydrocarbon generation potential of Shasi-Kongdian source rock,clear the hydrocarbon generation and expulsion characteristics of source rocks in every sub-segs and every formations,divide the evaluation units finely and forecast the oil and gas resource of every units,we also test the rationality of the simulation results.This study gives a certain guide for define the direction of exploration and deploy the well location.