3D fault plane SGR calculation for fault sealing in Petrel software: An example from Wenchang 9/8 area of the Pear River Mouth Basin, China

The Wenchang 9/8 area is one of the most promising hydrocarbon accumulation zones in the Pear River Mouth Basin, China. In this area, oil and gas are mainly accumulated in the Zhuhai and Zhujiang formations and their hydrocarbon reservoirs are generally related to faults, which are mainly located at the intersection area between NW-striking faults and NE-striking faults. Furthermore, previous petroleum exploration indicates that oil and gas are mainly sealed by faults. Therefore, high-resolution fault sealing calculation like shale-gauge-ratio (SGR) has a significant influence on further petroleum production. Present methods can only calculate single or discontinuous points of SGR for one fault and does not provide the SGR for the entire fault plane, which could impact future petroleum exploration. Testing several methods, we established the 3D fault plane SGR calculation method, which is based on the Petrel software platform. We then used this method on proven oil-bearing structures and target structures in the Wenchang 9/8 area. The results show that: (1) the 3D fault plane SGR of the fault, which controls the Wenchang 9-3 oil-bearing structure, reaches 35%-45%; the 3D fault plane SGR of the fault, which controls the Wenchang 9-7 oil-bearing structure, reaches 40%-55%. Therefore, the 3D fault plane SGR in Wenchang 9-3 and 9-7 oil-bearing structures are consistent with petroleum production; (2) For the target structures the 3D fault plane SGR in target 1 reaches 35%-55%. This is very high and supposed to be the next promising area in the study area, while the 3D fault plane SGR in target 2 is just 20-25%, which indicates high exploration risk at this target. Accordingly, we will promote this method for exploration targets in other petroliferous basins.