Print this pageSHALLOW LACUSTRINE DEPOSITION AND IMPLICATIONS FOR RESERVOIR DEVELOPMENT, PUTAOHUA SANDSTONE, DAAN BLOCK, SONGLIAO BASIN, P. R. CHINA
John S. Sneider1, Andrew S. Harper2,
James Wang3, and Lilly Zhang3
1 Sneider Exploration Inc
2 MI Energy Corp
3 PetroChina Jilin
In 2001, operator MI Energy and partner PetroChina drilled Well Da216-1 to test the Early Cretaceous Quantou Group, Fuyu and Yangdachengzi Sandstones (FuYang Sands), which are the main reservoir objectives in Daan Field. An alert well site geologist identified oil shows in a sandy siltstone interval in the Yaojia Group, some 500m above the main reservoir objective FuYang Sands. Wireline logs confirmed an oil pay zone 2.8m thick in the Early Cretaceous Yaojia Group, Putaohua Sandstone at a depth of 1315m. The Putaohua is known to be oil productive in nearby fields to the north, but this was the first identification of Putaohua oil pay in the southern Daan Field.
Putaohua Sandstone Reservoir at Daan Field
- Depth 1250-1350m
- Porosity 20-25%
- Permeability 8-75mD
- Pay Thickness 1.5 – 3.1m
- Initial Production Rates: 40 – 80 BOPD (34 – 35°API)
The Putoahua sands and silts are low-energy deposits, which are mainly flat-bedded, but occasionally ripple cross-bedded to small scale planar cross-bedded. They are interpreted to be shallow lacustrine, delta front sheet deposits, which accumulated in half-graben lows over an unconformity during a low stand in evolution for the Songliao Basin fluvio-lacustrine system.
Seismic isopaching suggests that Putaohua depositon is controlled by shallow NW-trending normal faults. Recent drilling confirms the seismic stratigraphic model and has led to six new Putaohua discovery wells adding significant reserves to Daan Field.