The Minagish field in West Kuwait is a high potential field which poses several challenges in terms of hydrocarbon flow assurance through highly depleted tight carbonate intervals with uneven reservoir quality and curtailed mobility. These conditions have shifted the field development from vertical to horizontal wellbore completions. Achieving complete wellbore coverage is a challenge for any Matrix Acid treatment performed in a long openhole lateral with disparities in reservoir characteristics. The fluid will flow into the path of least resistance leaving large portions of the formation untreated. As a result, economic Acid treatment options dwindle significantly, thus reservoir stimulation results are not always optimum.
A multistage acid stimulation technique using Integrated Dynamic Diversion (IDD) has been performed in a West Kuwait field well. The process uses active fluid energy to divert flow into a specific sweet point (high pressure point) in the lateral, which can pinpoint and precisely place acid treatment at the desired location. The process uses two self-directed fluid streams: one inside the pipe and one in the annulus. The process mixes the two fluids downhole with high energy to form a consistent controllable mixture. The technique includes pinpoint fluid jetting at the point of interest, followed by customized foamed HCL acid systems employed for improving individual stage targets in depleted reservoir. The IDD diversion shifts the acid treatment to unstimulated areas to create complex wormholes which increase reservoir contact volume and improve overall conductivity in the lateral. The kinetics and chemical diversion of the IDD methodology are highly critical to control fluid loss in depleted intervals and results in enhanced stimulation.
The application of the IDD methodology is a fit-for-purpose solution to address the unique challenges of openhole operations, formation technical difficulties, high-stakes economics, and untapped high potential from intermittent reservoirs. By utilizing this application in one continuous operation, the use of chemical diverters, straddle packers and mechanical plugs for selective treatment in open hole is eliminated, making this multistage completion technology economical for these depleted wells.
The paper presents results obtained after stimulating multiple zones along the lateral and describes the lessons learned in the implementation of this methodology. Going forward, the methods described, which can be considered a best practice for application to similar challenges in other fields. Proper candidate selection, optimum completion tools, and the fluid combination of in-situ gel-based diverter used to temporary plug the acid stimulated zone and foamed acid created an increase in the oil production of 430 BOPD.
