IDENTIFYING ROCK COMPRESSIBILITIES INFLUENCED ON DELTA FACIES AT SIMPANG PASIR AREA, SAMARINDA SEBERANG, KUTEI BASIN AND IT'S RELATED TO RESERVOIR CHARACTERIZATION

摘要

The Kutei-Mahakam Delta Basin is one of the controlled by 4 trendline, namely are compaction, uplift-cementation, cementation, and uplift-sorting.largest basin in Indonesia (165,000 km~2) and one of the richest hydrocarbon provinces with giant fields. It has a complex history and is one of the Indonesian basins to have evolved from a rifted internal fracture/foreland basin into a marginal-sag.The present study uses outcrop samples of Balikpapan Formation collected from Simpang Pasir area as the primary data. The outcrop data have been used as an analog to understand the lateral stratigraphy distribution and their relation to reservoir characterization based on rock physical analysis. The data were used to calculate compressibility of rock in dry condition and how their relation to affect porosity values related to geological processes.There are four facies associations found in the study area: Fluvial distributary channels, tidal-influenced distributary channels, distributary mouthbars, and flood plain deposits with NW-SE distribution trend.Laboratory analysis results show the porosities in fluvial distributary channel range from 11 to 23%, with compressibility values range from 0.48 to 0.55 Gpa; tidal influenced distributary channel has porosities ranging from 11 to 23%, and compressibility values range from 0.48 to 0.56 Gpa, in distributary mouthbar porosities range from 16 to 27%, with compressibility values range from 0.44 to 0.51 Gpa. Petrography analysis shows that pore type of the facies is predominantly intergranular porosity with calcite and ferro-oxide cementation formed during diagenetic processes.Analysis from wells data around study area show compressibility value ranging from 0.36-0.54 Gpa which the average porosity value from wells is