Study On Hydrocarbon Accumulation Rules Of JX1-1Oilfield, Liaozhong Sag

The Liaozhong Sag is a important hydrocarbon-rich Sag in Bohai Sea，it is alsoone of the main oil-gas producing areas of Bohai oilfield，JX1-1oilfield is a typicalrepresentative．JX1-1oilfield located in the central of LiaoZhong sag，and it islocated in a conversion parts which is a right-lateral strike-slip stretch and aright-lateral strike-slip extrusion zone of the Tanlu fault．Structure，sedimentary andhydrocarbon accumulation pattern are more complicated.Some basic petroleumgeological problems about JX1-1oilfield is not very clear，such as hydrocarbonsource，hydrocarbon accumulation period and age，hydrocarbon accumulationprocess and later reformation after accumulation．Therefore，this research is guidedby petroleum geology，tectonic geology，sedimentary petrology，oil and gasgeochemical，applied Balanced-Secion，oil sources correlation，fluid inclusionanalysis and basin modeling technology and methods to solve the problems above inthis area．Make clear JX1-1oilfield hydrocarbon accumulation process and rule issignificant for speeding up the pace of oil and gas exploration in LiaoZhong sag andoffering valuable experience of oil and gas exploration for other regions，theseresults are also significant for enriching and developing the theory research ofhydrocarbon accumulation in complex faulted basin．In this paper，Geochemical theory and method was used to evaluate the possiblesource rocks comprehensively. Based on this， we analyzed the oil source.Researchresults show that the organic matter abundance of source rock is high, besides Ed2source rock is medium abundance,the organic matter abundance of Ed3，Es1and Es3source rock is higher, they are good hydrocarbon source rocks, and each set of sourcerocks is mainly for the organic type II.Shallow oil has generally suffered frombiodegradation,it is difficult to use Gas chromatography to quantitative analysis the oil source,so we adopt the biomarker of sterane and terpane for oil-sourcecorrelation.Results show that the crude oil mainly comes from Es3source rocks，thetwo reservoir sections of Es1and Es2mixed with a small amount oil which comes fromEs1source rock.The fault sealing property is evaluated through the calculation of fault activityrate.The activity rate is less than10m/Ma in the sedimentary period of Es1stratum.Butin other period s， the activity rate is higher,the faults are good channels forhydrocarbon migration. The penetrative conglomerate above T2unconformity can beused as the hydrocarbon migration channels.Combined with previous researchachievements，the conducting system of research area is mainly fault+sand body.On the basis of single well burial history and structural evolution，the history ofhydrocarbon generation and thermal evolution are simulated.Used the results ofreservoir fluid inclusions analysis and test to identify oil accumulation stages.Thehydrocarbon accumulation of JX1-1oilfield has the characteristics of two stages ofhydrocarbon-charging.The first stage is the sedimentary end of E3d， and the otherone is the sedimentary end of Nm until now.T hereby，the hydrocarbon accumulationmodel is established，JX1-1oilfield has the characteristics of early ancient reservoirdestruction and late hydrocarbon-charging reservoiring again.In addition，the oil andgas of east pieces are mainly from the source rocks of west block which have a greaterburied depth. Integrated predecessors’ achievements we put forward JX1-1oilfieldhydrocarbon accumulation controlling factors of4points.