WATER BUBBLING ANALYSIS ON LIMA SAND WATERFLOOD IN FOXTROT FIELD - CASE STUDY

• Main Author: SETIAWAN (NIM: 22207312), TAUFIQ
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/24490
• Institution: Institut Teknologi Bandung

Waterflood operation at Lima sand has been performed since year 2003 until today. Lima sand is a shallow, shally sand and soft reservoir at 550 - 700 feet <br /> <br /> <br /> deep. Poor reservoir characteristics and compartmentalized make it good candidates for fracturing stimulation that have been done at most of the wells, to <br /> <br /> <br /> increase production rates. In other hand, geological process had resulted Lima shale break weaker and possibly discontinuous due to bending process. Water <br /> <br /> <br /> bubbling due to high well head injection pressure then appears at the surface which has never been happened in waterflood operation. <br /> <br /> <br /> Fluid sample is one of important key to predict where the fluid is come from, what the causes are, and how to take care and make sure this incident will not happen in <br /> <br /> <br /> the future. Laboratory test tells that the fluid is purely water with no hydrocarbon sign, then it is sure that this incident is coming from waterflood operation <br /> <br /> <br /> especially injection wells that injecting in high injection pressure to reach injection rate target. Previously, it was suspected that bad cement bond is the <br /> <br /> <br /> cause of this problem where the water could break and flow through behind casing to surface water formation. The next suspicion is due to fracture stimulation jobs <br /> <br /> <br /> at Lima sand that has been done at most of wells in Foxtrot field. High treating pressure had resulted major and minor fracture at spread directions, especially at <br /> <br /> <br /> vertical direction. Combinations of the fractures, the weaker shale break, and high injection pressure have created channels to the pressurized water to break and <br /> <br /> <br /> flow through the shale break and surface water formation, then finally flow on the surface. <br /> <br /> <br /> The thesis methods are started with collecting fluid samples and supporting data. <br /> <br /> <br /> The supporting data are consist of data that possibly have any relations with water bubbling incident, like CBL from offset wells, injection histories, workover <br /> <br /> <br /> database for Foxtrot field especially fracture stimulations completed with their post job reports, completion data both of injection and production wells of offset wells, and also seismic map. These data then evaluated and analyzed together with Petroleum Engineers and Earth Scientist that resulting a make sense and the best hypothesis. <br /> <br /> <br /> Turn out, cement bond has gave no impact on water bubbling based on the available data, while fractured stimulations and waterflood at Lima sand and also <br /> <br /> <br /> given geologist aspects are the cause of this incidents. It is then recommended to stop injection on Lima sand, especially on high structure wells, drill more wells to <br /> <br /> <br /> reduce spacing, and fracture stimulate those new wells.