--> Crossflow Mitigation Through Geomechanic Investigation In Mature Panda Field, West Java Basin, Indonesia

AAPG Asia Pacific Region GTW, Pore Pressure & Geomechanics: From Exploration to Abandonment

Datapages, Inc.Print this page

Crossflow Mitigation Through Geomechanic Investigation In Mature Panda Field, West Java Basin, Indonesia

Abstract

Breakouts and tensile fractures are drilling induced features that occur due to different stress applied in the well. Besides acting as a stress indicator, those two features could act as a fluid conduit between formations. Those features have the potential to become a pathway for cross flow, especially when the well components such as casing or cementing have deteriorated due to its age.

Panda Field is a mature oil field which located in Ciputat Sub-Basin, West Java Basin, Indonesia. Main producing reservoir from Panda Field is a fractured basement reservoir with low grade metamorphism. Acquired image logs from the development wells have shown not only the presence of open fractures but also breakouts and tensile fractures all over the reservoirs. The formation pressure in Panda Field has been depleted throughout the production in an order of hundreds psi. Secondary or tertiary recovery is going to be required to maintain the production rate. Those recovery methods often require injection of fluid into the reservoir. However, drilling induced features which deform borehole geometry and could not be completely sealed by cement are susceptible to becoming a pathway from the perforation to other intervals. Therefore, minimizing both drilling induced features in reservoir becomes essential in drilling new development well or selecting suitable old well as a candidate for secondary or tertiary recovery.

Geomechanic investigation was used to predict potential crossflow in production wells. The investigation method started by creating a geomechanic model for each well. Then the stress magnitude and orientation were used to model the occurrence of borehole breakout and tensile fracture calibrated with existing image log. The calibrated parameters were then used to create a well prognosis. Several scenarios using variety of mud weight were used to do a sensitivity analysis. The result is able to create a window where mud weight has to be maintained when going through the reservoir. This crossflow mitigation is one of well integrity analysis to make sure that the wells are being drilled without extensive damage to the reservoir and could be utilized for further field development, such as improved oil recovery or enhanced oil recovery.