Sedimentray facies analysis of lematang area in south Palembang sub-basin based on the well logs data

ZAMAN, Mohd Firdauz Bin Kamlul, Dr. Sugeng Sapto Surjono, ST., MT

2010 | Tesis | S2 Teknik Geologi

Sekuen stratigrafi adalah metode analisis stratigrafi modern, dimana pola susun strata dan hubungan fasies dari batuan sedimen dipelajari dalam kerangka waktu. Fasies log sinar gamma digunakan dalam kolerasi log sumur untuk mencerminkan dan menentukan lingkungan pengendapan dan didukung dengan data seismik yang dapat membangun lingkungan pengendapan di daerah penelitian. Tesis ini menyajikan hasil studi log Wireline daerah Lematang, Sub-Cekungan Palembang Selatan. Tujuannya adalah untuk membedakan karakter log sedimen dan memberikan interpretasi awal dalam bidang sedimentologi, dan paleogeografi daerah penelitian. 43 data sumur digunakan untuk korelasi dengan menggunakan tiga metode korelasi utama yaitu lapisan penanda, asosiasi unit, dan pertimbangan lingkungan pengendapan. Tesis ini berfokus pada penggunaan informasi log wireline untuk mengindentifikasi sistem lingkungan pengendapan. Dalam analisis akhir, lima fasies log dapat ditentukan dalam interval batuan yang dipelajari yaitu ―thick funnel-shaped‖ mewakili fasies prograding delta; ―thin funnel-shaped‖ mewakili fasies crevasse splay; ‖boxcar-shaped‖ mewakili facies distributary channel; ―bell shaped‖ mewakili fasies fluvial atau deltaic channel dan ―irregular-shaped‖ mewakili fasies floodplain. Daerah Lematang di Palembang Sub-Cekungan diinterpretasikan sebagai hasil imbrikasi progadasi delta pada suatu sistem delta skala kecil

Sequence stratigraphy is a modern method of stratigraphic analysis, whereby strata stacking patterns and facies relationships of sedimentary rocks are studied within a temporal framework. Gamma ray log facies were used in well log correlation in order to reflect and determine the depositional in the research area. This paper presents the results of a wireline log study of the Lematang area, South Palembang Sub-Basin. The purposes are to distinguish the log characters of the sediments and provide a preliminary sedimentological and paleogeographical interpretation of the study area. About 43 wells are picked by using three major correlation methods i.e. marker bed, unit association, and consideration of depositional environments. This paper is focused on the use of wireline log information for identification of the depositional environment system. In the final analysis, five log facies were recognized in the studied intervals: a thick funnel-shaped facies representing a prograding delta; a thin funnel-shaped facies representing a crevasse splay; a boxcar-shaped facies representing a distributary channel; a bell-shaped facies representing a fluvial or deltaic channel and irregular-shaped facies representing a floodplain. The paleoenvironment of the Lematang area in Palembang Sub-Basin is interpreted as the results of imbrication of a prograding delta are all in a small-scale delta system.

Kata Kunci : Well log,Stratigrafi,Paleoenvironment,Lematang, Well log , Stratigraphy, Paleoenvironment, Lematang)