Rock Physics Analysis of Low Resistivity Low Contrast in Bioturbated Sand, Case Study; Sepat Field

Low resistivity and low contrast zone have been identified in clastic rock bodies and one of the reasons for this behavior is due to bioturbated sand. The resistivity of this zone is similar to the resistivity of formation water bearing zone. To understand this unique behavior, study is focused on investigation of clastic rock bodies which includes the bypass zone otherwise known as bioturbated sand. Features of clastis deposits were studied while understanding environment of bioturbated sand is also undertaken. The main objective of the research is to evaluate the LRLC zone with accompanied objective including investigating clastic sediment from selected Seri Iskandar outcrop and doing fieldwork in Pantai Seri Tujuh to enhance the understanding of modern environment of bioturbated sand.

The scope of this research to complete first phase of FYP includes collecting data and sample from Seri Iskandar (preliminary research area), Kelatan (preliminary research area), and Sepat Field, investigating structural and clastic features of outcrop, and describing mineral composition of selected outcrops. Method incorporated into this investigation is divided into two which is field work and laboratory work. It is found that clastic deposits in Seri Iskandar is made up of cemented quartz with minor feldspar while petrographic studies deducted the sandstone in Seri Iskandar is compositionally and texturally matured.

Second phase of the Research includes laboratory method to measure and determine acoustic and elastic properties of samples in Seri Iskandar and Sepat field. The effect of velocity response is a focus during this period. Physical measurement and calculation are used to describe properties of the rock. Understanding these properties would enable to understand whether the rock is capable of conducting acoustic wave efficiently and what causes the wave motion to be disturbed. However, the results would not be entirely accurate due to lack of samples. All the factors that influence wave velocity response are discussed within this dissertation.