New Biosurfactant Method in Stimulation Technology

Abstract

Stimulation is a well intervention technology that injects special fluid to formation reservoir in order to change either fluid characteristics or reservoir properties. This special fluid is often chemical and in some cases microbes, which also known as bio-surfactant. After injecting microbes and nutrients to reservoir, microbes will produce bio-surfactant enzyme that encapsulates hydrocarbon. This event will cause oil drop to deform, split, and release from tight pores and then flow to wellbore. Unlike conventional bio-surfactant technology that uses actual microbes, a new approach was made in field Jambi by directly injecting bio-surfactant enzyme (the final product) into reservoir. The enzyme used is Bio-surfactant Enzyme for Recovery of Oil (BERO).

Candidates for BERO was chosen in AK structure layer 360. This layer has 19 ˚API and 50 cp viscosity. The fluid is heavy but not too severe. The problem was this layer also has sand problem, while BERO couldn’t be executed in unconsolidated sand reservoir. Since this layer is promising to be stimulated, wells that has been performed sand control and succeeded in maintaining base sediment (BS) under 0.5% were chosen.

As a type of surfactant, BERO change wettability of rock surface from oil wet to water wet and reduce interfacial tension (IFT), thus higher production rate and recoverable factor. Conventional bio-surfactant method injects bacteria or microbes to reservoir that will produce bio enzyme. But this method would have big chance to fail if the microbes died. With BERO, bio-surfactant enzyme was directly injected into reservoir. First, laboratory test was performed on BERO. Compatibility test showed that BERO is compatible with AK brine with no precipitate was formed in the mixture. IFT test proved that with BERO 2% IFT can be reduced from 5.89 mN/m to 1.69 mN/m. Lastly, spontaneous imbibition test results in increase of recovery factor from 29.51% to 52.58 %. Based on this promising laboratory test, well AK245 in AK Structure was chosen as pilot treatment.

By applying this surfactant well AK-245 get incremental production more than 50%. Before treatment this well had 24 BFPD /16 BOPD/31% last production test on December 10th 2019 and after treatment we got peak production of 33 BFPD/ 26 BOPD /20% and pump submergence increases from 6 m to as high as 148 m. Cumulative production after treatment is 2172 bbls from December 2019 until now.Production and fluid level survey show that this treatment applied successfully in well AK-245. Next chapter are to optimize the well and continue the treatment on other wells in AK structure.

Applying this new bio-surfactant method shows promising result that vouches its lab test and unlocks potential to continue treatment in other wells and structures.