The Peng Lai (PL) 19-3 Oil Field, located in the ConocoPhillips operated Bozhong 11/05 Block in the central southern Bohai Sea, offshore China, is currently the largest offshore oil field in China. The trap is a complex wrench anticline developed along the Tanchen-Lujiang fault system. The main oil accumulation is in the Neogene Lower Minghuazhen and Guantao Formations with a vertical relief from the top reservoir to the deepest oil bearing rock of approximately 500 meters. The PL 19-3 Oil Field, deposited in a fluvial environment, is a complex stacking of unconsolidated sandstone reservoirs, with moderate porosity and permeability and low net gross ratio. The trap has been divided recently into numerous fault blocks which have unique contacts and variable oil properties both vertically and laterally, with oil gravities ranging from 12 to 22 API. This paper reviews the pressure acquisition history and analysis from the 160 well formation test database, which includes both wireline formation test (WFT) and formation test while drilling (FTWD). Formation testing in the Neogene formation of Bohai Bay is challenging since the reservoir is unconsolidated and the oil is heavy. Common problems that affect pressure testing are described, efforts to enhance test efficiency are stated and key learnings and best practices to secure high quality pressure data are summarized. Conventional pressure interpretation to derive fluid gradient and oil water contacts, identify reservoir compartmentalization and flow barrier is challenged due to small density contrast between the heavy oil and water in the field. The excess pressure method, which is attributed to formation water properties and consistent hydrostatic pressure gradient in the field, has been an effective way to analyze pressure data. In this paper, the historical application of excess pressure in the industry is reviewed, examples of the excess pressure interpretation in PL 19-3 Oil Field are given and integrated interpretation practices are emphasized. Pressure data have wide application in the PL 19-3 oil field. This paper summarizes and demonstrates how original excess pressure and dynamic logging while drilling (LWD) pressure data have been used successfully to predict oil water contacts, to analyze fault transmissibility, to monitor water flooding efficiency, to identify fluid properties, to interpret fault cuts in wells, to optimize mud weights while drilling and to mitigate risk and well bore damage during completion operations
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