Fault Pathway Systems And The Reservoir-controlled Laws In Southern Jinhu Depression

The faults in the Southern Jinhu depression widely developed and the hydrocarbon enrichment degree is very high, it is indicated that the hydrocarbon accumulation are controlled by faults Obviously. Because of complex fault system and the diversity of oil and gas distribution, pathway system of faults with the core of fault sealing has become more urgent and important.The fault is divided into four classes, of which the level three most developed; In section single fault shows plate or shovel types,multiple faults show "Y" fonts and fault step types. Application of balanced cross-sections technique and backstripping inversion of original stratum thickness fault development history is analyzed,faults activity of level three and four are the strongest in Member four of the Funing formation,to the late Sanduo formation fault activity gradually stopped.Based on the fault feature summary, 19 faults are Selected to evaluate and predict fault sealing ability. In Dongyang region Lateral and vertical sealing of fault is worse in Member two and three of the Funing formation,and is better in Member four of the Funing formation. In Chajian region, Lateral sealing of fault is better, vertical sealing is also better in Member four of the Funing formation, but is worse in Member two and three of the Funing formation. In Longgang region Lateral sealing of fault is better, vertical sealing of fault is worse.The differences of the configuration feature between sand body and fault are obvious in three regions. In Dongyang, the combination patterns are configurations of level three fault with worse sealing ability and skeleton sand. In Chajian,the combination patterns are configurations of fault with worse vertical sealing, better lateral sealing and skeleton sand; In Longgang, the combination patterns are configurations of fault with worse vertical sealing, better lateral sealing and skeleton sand under source rocks in Member two of the Funing formation. Under the restriction of pathway systems configuration the migration pathways also have very big difference. In Dongyang, the oil and gas migrate through faults along the sand body distribution pattern to the slope with high structural location; In Chajian, the oil and gas migrate along with fault step to slope, but the branch fault block the migration; In Longgang, the oil and gas migrate along sandstone in Member two of the Funing formation to Bianminyang structural zone,and when they meet the fault of worse vertical sealing they migrate into sandstone in Member three of the Funing formation.In Dongyang region the favorable exploration direction is to search the fault-nose or fault-block traps in fault step controlled by level three fault; The favorable exploration direction in Chajian region is to search the fault-block trap which has block fault in effective hydrocarbon-expulsion range near the sub-depressions; In Longgang region the fault-nose or fault-block traps in effective hydrocarbon-expulsion range are favorable exploration direction targets of which has the sandstone developed under the source rock.