Integrated Reservoir Characteristics And Production Enhancement Strategy Of Tight Oil Reservoir In Upper Talang Akar Formation Case Study Limau Field – South Sumatera Basin

Abstract

Low quality and tight oil reservoir is a crude oil contained in low permeability formation, including but not limited to shale. Oil reservoir with low quality and tight was initially unattractive to be developed, it is very low porosity (< 10%), very low permeability (<0.2 mD) and high water saturation (>95%) but eventually given unpredictable oil production performance Every low quality and tight oil reservoir is unique and field development should be determined based on individual petrophysical attributes, reservoir characteristic and production enhancement strategy. In this paper, reservoir and production characteristics of low quality and tight oil reservoir are summarized, the investigated reservoirs include calcareous sandstone reservoir in Upper Talang Akar Formation, AN Structure. Almost mud logging data unit is also captured very low gas reading (only up to C3) and no traces oil show during drilling activity. Pressure measurement using wireline formation test (XPT) and modular dynamic tester (MDT) is also confirmed loss seal and supercharged. The primary key evaluation that have led to identify hydrocarbon in tight oil reservoir on this paper are : a. Petrophysics interpretation attributes is optimized by Dipole Shear Sonic Imager (DSI) and surrounding well data analogy. b. Certain criteria were used to select the pilot well test such as gas chromatograph or formation cutting log, nearby well correlation, single open hole log and the distance from key well refference. c. Acid solubility data labtest as critical part of production enhancement strategy The result of petrophysic optimization is given more optimistic water saturation, but reservoir properties such as permeability and porosity is still needed to be enhanced. As primary recovery is quite low in tight oil reservoirs, the production enhancement strategy is necessary and it must be conducted based on a deep understanding of petrophysical and minerals contained in the rock matrix. Deep penetration of matrix stimulation HCl 15% seems the best fit in this case.As a result 8 idle wells were perforated and stimulated HCl 15% during 2019 - 2021. It has been an attractive oil production result with incremental reach to 822 Bopd, 45 - 60% water cut and 247 MSTB oil production cumulative. Well stimulation job has to be conducted periodically to maintain stiff production decline By understanding the characteristics of tight oil reservoir and proper production enhancement strategy, this paper can be expected engineers to unlock potential hydrocarbon and increasing the production,