油源断裂油气成藏期优势通道输导能力综合评判方法及其应用

本文通过油气成藏期油源断裂不同部位古活动速率相对大小分布，确定其油气输导的优势通道。并基于优势输导通道的断裂古活动速率、古倾角、目的层古埋深和源岩古剩余地层压力等指标，建立了一套油源断裂在油气成藏期优势通道输导能力的综合评判方法。以渤海湾盆地冀中坳陷廊固凹陷为靶区，对大柳泉区块旧州油源断裂带在成藏期沙三中下亚段内的优势通道进行了厘定和油气输导能力综合评判。评判结果表明：旧州油源断裂6条分支断裂油气成藏期——沙二段沉积时期发育了10个优势通道，其油气输导能力以F₁和F₂分支断裂的6个优势通道输导油气能力相对较强，有利于油气运移，F₃、F₄、F₅和F₆分支断裂发育4个优势通道，其输导油气能力相对较弱，不利于油气运移。此评判结果与目前旧州断裂带附近沙三中下亚段内的油气分布现状相吻合，表明用此方法进行油源断裂成藏期优势通道的输导能力综合评判是可行性的。

Comprehensive Evaluation Method for Oil and Gas Transmission Capacity of Oil Source Fracture Dominant Channel in Oil and Gas Accumulation Period and Its Application

Based on the relative size distribution of the ancient activity rate in the different parts of the oil source fault during the hydrocarbon accumulation period, its dominant channel for transporting oil and gas was determined. Based on the fracture activity rate, the ancient dip angle, the paleo-burial depth of the target layer, and the paleo-remaining stratum pressure of the dominant transport channel, the comprehensive evaluation method of the oil and gas capacity of the oil source fault dominant channel during the hydrocarbon accumulation period was established, and applied to the comprehensive evaluation of the oil and gas capacity of the dominant channel in the middle and lower sub-members of the third member from Shahejie Formation in Daliuquan area of Langgu depressions in Bohai Bay basin. The results show that ten dominant channels developed during the sedimentary period of the six branch faults of the oil-bearing faults of the Jiuzhou oil source. The oil and gas transport capacity is relatively strong in the six dominant channels of F₁ and F₂ faults. Four dominant channels developed in F₃, F₄, F₅ and F₆ fractures developed, and their oil and gas transport capacity is relatively weak and not conducive to oil and gas migration. This evaluation result is consistent with the current status of oil and gas distribution in the middle and lower sub-members of the third member from Shahejie Formation in the vicinity of the Jiuzhou fault. This indicates that the method is feasible for comprehensive evaluation of oil and gas transport capacity of the dominant channel during the accumulation period of the oil source faults.