Feasibility Study of Various Litho-Fluid Indicators for Better Hydrocarbon Prediction in Malay and Adjacent Basin

Abstract

The application of lithology and fluid indicators has helped the geophysicists to discriminate reservoirs to non-reservoirs from a field. This analysis is conducted to select the most suitable lithology and fluid indicator for the Malay basin that could lead to better eliminate pitfalls of amplitude. This paper uses different rock physics analyses such as Poisson’s impedance, acoustic impedance, shear impedance, elastic impedance, LambdaMuRho (LMR), and SQ_p–SQ_s attribute. Poisson’s impedance (PI) log is generated by using the method by determining the constant from AI–SI gradient. Then, litho-elastic impedance log is generated by correlating the gamma ray log with extended elastic impedance (EEI) log. The same application is used for fluid-elastic impedance by correlation of EEI log with water saturation or resistivity. The work is done on several well log data collected from different fields in Malay basin and its neighboring basin. Preliminary observations are done for three wells: Well 1, Well 2, and Well 3. The constant c in PI log for Well 2 is 1.305 and 1.58 for Well 3. There is an excellent separation between hydrocarbon sand and background shale for Well 3 from different cross-plot analyses. The similar method done on the Well 2 shows fair separation of silty sand and gas sand using SQ_p–SQ_s attribute which can be correlated with well log data. Meanwhile, the third well shows good separation in LMR plot. Based on the point distribution histogram plot, different lithology and fluid can be separated clearly. There are many attributes available in the industry used to separate the lithology and fluid; however, some of the methods are not suitable for the application to the basins in Malaysia.