Integration of 4D Microgravity, Geology and Production Data to Monitor Water Injection in Improved Oil Recovery Project, Diamond Field
Authors: Hadi Sriyanta , Alawiyah Susanti , A. Kadir Wawan Gunawan 
Published: May 2016

Abstract
Water injection is common technology applied to maintain the reservoir pressure under Improved Oil Recovery (IOR) scheme. Reservoir pressure maintenance is required to sustain the oil production and maximize oil recovery. Water injection is to be technically and economically designed, properly implemented and thoroughly evaluated. When the water injection is commenced, it is essential to conduct technical evaluation to monitor its effectiveness in order to achieve the goal and objectives. Understanding the reservoir fluid dynamics including the injected water movement is the key for optimizing the water injection. Production, geological and geophysical data are to be integrated to portray the reservoir fluid saturation changes. A comprehensive analysis of time lapse (4D) microgravity, production and geology is used to evaluate the water injection performance. The 4D microgravity that passively surveyed at the arranged stations is easy to operate, competitive and technically accepted. Several time-lapse microgravity that was surveyed in water injection IOR, Diamond field, would provide different time lapse microgravity anomaly for further analysis. This research applies forward modeling of microgravity anomaly to match with the reservoir production performance. The outcomes from this joint study would then be used to support continuous water injection optimization and improvement. Other than subsurface integration, from surface operation point of view, water injection improvement also involves surface discipline which consists of production operations and construction that responsible for surface facilities operations and construction.

Introduction
There are at least three good reasons why the evaluation of water injection in IOR project is to be carried out by integrating production, 4D microgravity and geology. Firstly, water injection in IOR project is crucial; it directly affects the oil production in the short term and determines the ultimate oil recovery in the long term. Secondly, the integration enables us to examine matching between the production performance and the water movement indicated by 4D microgravity. Thirdly, it is beneficial to apply competitive 4D microgravity technology rather than applying expensive and long lead technology.
Water injection for pressure maintenance and IOR is widely implemented. The effectiveness of water injection in IOR is the success factor in maximizing oil recovery because it maintains the reservoir pressure which acts as the energy to sustain the oil production from reservoir. The water injection is designed by considering the injection pattern, the injection rates and the injection pressure as well as the operational accessibility and water quality requirement. Commercially, effective water injection in IOR project will increase and sustain the production, and finally it will generate the maximum revenue.
Monitoring and analyzing the reservoir and production performance is commonly conducted through analytical and reservoir dynamic simulation. Beyond the normal method, integration between 4D microgravity and production can be chosen to monitor the fluid movement in the reservoir. The integration of 4D microgravity, production performance and geology provides a better understanding on the reservoir conditions compared to just having reservoir and/or production performance analysis alone.