Abstract: Low Resistivity, Low Contrast Pays: Part II-Comparison of Examples from Southeast Asia and the Gulf Of Mexico

John T. Kulha, Robert M. Sneider

The Gulf of Mexico Basin (GOM) is the world's leading oil and gas producer from low resistivity, low contrast (LRLC) clastic intervals. Many GOM fields have had production from LRLC pays for more than 15 years and some for over 40 years. LRLC pay zones are being recognized more frequently now in other basins in the world, including southeast Asia.

LRLC pays in southeast Asia have many similarities and some differences with the LRLC producing zones in the Gulf of Mexico Basin. The depositional environments containing LRLC pays in southeast Asia are (1) major regional and local marine transgressive sands, (2) deep-water sands, including levee-channel complexes, (3) deltaic channel and bar-front sands, and (4) shingled turbidites. LRLC pays in marine transgressive sands are more abundant in southeast Asia.

The principal causes of LRLC pays in southeast Asia are similar to that of the Gulf of Mexico (discussed in part I). In southeast Asia, because of the tectonic sediment source areas, short transport to the basin, and immaturity of the reservoir sands, clay-altered rock fragments are much more common than in the GOM. The four most common causes of LRLC zones in southeast Asia are (1) thin beds or laminae of clean sand or shaly sand alternating with very shaly sand, siltstone or shale, (2) shaly sands with dispersed clay and abundant clay-mineral alteration of framework rock fragments including volcanic grains, (3) glauconitic sands with glauconite content up to 35% of the framework grains, and (4) clay-coated sands.

Geological and petrophysical models developed in the Gulf of Mexico to identify and evaluate LRLC pays are applicable to southeast Asia LRLC intervals. Several LRLC pay examples from the Gulf of Mexico and southeast Asia are compared.

AAPG Search and Discovery Article #90982©1994 AAPG International Conference and Exhibition, Kuala Lumpur, Malaysia, August 21-24, 1994