London-listed oil and gas company Empyrean Energy has completed a comprehensive oil migration study encompassing Block 29/11 offshore China, which resulted in “very promising” findings.
Empyrean said on Monday that the study over the company’s 100 percent-owned block established potential oil migration pathways into the Jade, Topaz, and Pearl prospects.
The study was supported by geoscientists from CNOOC’s Shenzhen branch who shared the viewpoints of its previous study in this area.
The company added that the migration study found that the proven Baiyun Sag East (BSE) basin had an oil migration pathway to Block 29/11 and that the BSE area was at peak maturity.
The main implications for Block 29/11 prospectivity were interpreted to be very positive with the entire source rock within BSE interpreted to have produced hydrocarbons. In addition, any potential oil accumulation in the prospects within the block are expected to be light and therefore similar to the oil discoveries around Block 29/11 that range from 33-38 API.
The study also validated the interpreted oil migration pathways from the known oil sources of the Paleocene-aged Enping formation within the BSE into the several oil discoveries made by CNOOC to the immediate west and south of Block 29/11 since 2010, and thus provided strong evidence of a prolific petroleum system in the area.
At the same time, the study interpreted effective migration pathways from BSE towards the northern flank of the Baiyun uplift where the Jade and Topaz prospects are located.
Also, 28 square kilometers of 3D seismic data that was acquired outside Block 29/11 over the 2013 CNOOC oil discovery designated LH 23-1d-1, located eight kilometers west of the Jade prospect, helped confirm potential “fill-and-spill” pathways to the Jade structure from the oil discovery.
“Whilst early exploration techniques such as this are no guarantee of exploration success, the company believes that this form of “seismic tie” to a nearby known discovery helps to reduce the risks associated with exploration and provides an improved understanding of the geology in the basin and within Block 29/11,” said Empyrean.
Comprehensive interpretation of the 2017 3D seismic data helped map a new sub-basin called Baiyun Sag North. BSN is located between the Jade and Topaz prospects and is located entirely within Block 29/11. The study confirmed a potential effective migration pathway from BSN into the Jade and Topaz prospects.
The study also indicated that the Pearl prospect was potentially located in a migration shadow for oil migrating from BSE or BSN. As a result, further work was done focussing on the possibility of migration from the Huizhou Sag located northwest of Block 29/11.
The Liuhua 11-1 field complex that contained an estimated 1.1 billion barrels of oil is located immediately north of Block 29/11 and was interpreted to have received oil from Huizhou Sag. Additional work indicates that the Pearl prospect is located favorably for receiving oil charge from Huizhou Sag.
Empyrean CEO, Tom Kelly, said: “The findings from this oil migration study are very promising with effective potential oil migration pathways established into all three of our prospects on Block 29/11. Interpretation of the potential effective migration pathways from the established kitchen area – Baiyun Sag East – as well as from the new kitchen area – Baiyun Sag North – into Block 29/11 helps increase our overall understanding of the geology of the block and the Jade and Topaz prospects in particular. The additional work has also confirmed a potential oil migration pathway from the Liuhua 11-1 field complex to the Pearl prospect.
“[…] the detailed and comprehensive technical work we have completed to date significantly reduces the geological risks to a point where we have established excellent drilling targets that are of significant size with relatively low geological risk.”