呼和诺仁油田孔隙结构及渗流特征研究

Study on pore structure and seepage characteristics in Huhenuoren oilfield

针对海拉尔盆地呼和诺仁油田南屯组油层含水上升快的实际情况,开展了储层孔隙结构和渗流特征研究。南屯组储层近物源、快速堆积的扇三角洲沉积导致孔隙分布不均、连通性差,喉道分布以双峰型为主,左峰对应较小喉道半径,为无效喉道;右峰对应较大喉道半径,为有效喉道,是主要渗流通道。孔隙结构相差极大,微观非均质性极强。可动油饱和度较低,水相相对渗透率形态呈凸形。储层水敏性强、贾敏效应渗流阻力大导致水驱油过程中注入水很难进入1μm以下喉道驱油,由核磁共振测试得到1μm以上喉道中采油量占全部采油量的77%,为注入水渗流的优势通道,是油井含水上升快的主要原因。

Pore structure and seepage characteristics have been studied in view of the rapid rise of reservoir water cut in Nantun for- mation of Huhenuoren oilfield of Hailar basin. In the reservoir of Nantun formation, the fast accumulated fan delta deposition near provenance leads to uneven distribution of pore and poor connectivity. Throat distributes in the shape of dual peak. Left peak is in- effective throat with small radius while right peak is effective throat and main seepage channel with large radius. Pore structure varys greatly and micro-heterogeneity is strong. Mobile oil saturation is low and water-phase relative-permeability is convex. Due to strong water sensitivity, Jamin effect and big seepage resistance, injection water can hardly enter the throat of less than 1 txm to drive oil. According to NMR test, the throat of more than 1 μm contributes 77% of the total oil output, and as the preferential chan- nel for injected water seepage, it＇ s the main cause for the rapid rise of oil well water cut.