Neogene reservoirs and hydrocarbon accumulation in the Laoyemiao Oil Field, Nanpu depression, Hebei

The Neogene Guantao and Minghuazhen Formations have long been the key horizons in the exploration and development of the Laoyemiao Oil Field, Nanpu depression. The Neogene strata in this area mainly consist of the fluvial deposits. These well-sorted reservoir rocks are composed of arkose and lithic arkose, and contain mesopores and macropores. The diagenetic are relatively weak. The precipitation of carbonates is considered as an important factor in controlling the decrease of primary porosity.The porosity types consist dominantly of intergranular porosity.The intergranular solution openings and intragranular solution openings are rare in the Guantao Formation. The diagenesis of the reservoirs facilitates the hydrocarbon accumulation. The sedimentary microfacies of the reservoirs may exercise a major control on the hydrocarbon accumulation and distribution. Both the channels and abandoned channels have good reservoirseal associations, and are thus interpreted as most favourable facies belts for the hydrocarbon accumulation. As for the sealing conditions, the channel bar sandstones are not favourable as the channel sandstones and thus have relatively poor oil potential.