High-quality hydrocarbon source rock in the Paleogene sequence of the Ping Chau Formation, Hong Kong

Abstract

Although petroleum exploration is being conducted in the Hong Kong region, high-quality hydrocarbon source rocks have never been found in this area. The Ping Chau Formation is only Mesozoic-Cenozoic sedimentary rock exposed in Hong Kong and its surrounding areas. The hydrocarbon source rock of the Ping Chau Formation is very rich in organic matters, which has an average total organic carbon (TOC) of 1.9% and chloroform bitumen "A" range from 0.14% to 0.24%. The total hydrocarbon content varies from 880 to 1800 ppm and the transformation ratio is specific from 5 to 9. The index of pyrolytic hydrogen is up to about 600 mgHC/gTOC. These data demonstrate the characteristics of the high-quality hydrocarbon source rock. The lamalginite is the major maceral of the source rock of the Ping Chau Formation, and geochemical characteristics also suggest that the organic materials of the source rock are of type I and type II 1 , with abundant gammacerane, γ, β-carotane and C 24 tetracyclic terpane, which indicate that it was formed in the salt water and brackish water sedimentary environment, and the source rock has evolved into a mature phase. The organic inclusions are found within calcite veins in cracks of the source rock, indicating that hydrocarbon has been generated and a secondary migration has happened. The source rock in the Ping Chau Formation is about 200-300 m thick, thus having considerable hydrocarbon potential. The discovery of the high quality hydrocarbon source rock in the Ping Chau Formation will certainly provide insight on hydrocarbon resource exploration in the South China Sea area.

Cenozoic evolution and deformation in the Eastern and Western Depression of the Liaohe Subbasin, Bohai Bay Basin: Insights from seismic data

“…Seven key seismic surfaces were interpreted to constrain the throw distributions on the fault surface and the thickness variations in the stratigraphy adjacent to the faults (Figure 4). The strata and related sedimentary ages used in this study were obtained by combining palaeontology, palaeomagnetism and isotopic dating of volcanic rocks to ensure that data pertaining to lithology and stratal ages for all investigated wells were credible (Chen & Peng, 1985; Li et al, 1992; Liang et al, 1992; Yao, 1994). In addition, well data (mainly acoustic and density logs) from two wells (the G1 and L1 wells in Figure 3) were used to generate a synthetic seismogram for horizon calibration (Figure 4).…”

“…The 3D seismic data were zero-phase with inline and crossline spacing of 25 × 25 m F I G U R E 4 Simplified tectonostratigraphic diagram of the Liaohe Subbasin. Ages are determined from micropalaeontologic data, for example ostracoda and palynologic data, palaeomagnetic dating and volcanic rock dating (Chen & Peng, 1985;Liang et al, 1992;Yao, 1994). The G1 well (Figure 2) was used as a reference well to finely define horizons.…”