Successful Field Applications of Installing and Activating High Pressure/Temperature Multi-Stage Completion for Improving Well Performance in Deep North Kuwait Jurassic Formation

Abstract

Abstract In the last decades, defining optimum completion options in North Kuwait Jurassic Gas (NKJG) were essential to overcome reservoir challenges, connect to natural fractures, minimize formation damage, and stimulate formations efficiently in this sour gas environment. Moreover, the completion should withstand high-pressure differential (~15,000 psi) and high temperature (~275oF) during installing and producing over entire well life (over 20 years). The efficient completion type that suits NKJG environment will ensure enhancing the future well interventions and increase production potential within a short time period. NKJG’s reservoirs are classified as high-pressure, high-temperature, sour, deep, with high contrast in permeability values (2 to 3 order of magnitude), and high variation of natural fracture distribution among well locations. In addition, the major flow zone of interest is divided into several segments with different reservoir properties and lithology which affect the production zonal contribution. The cased and perforated liner completion were used in this challenging area where low permeable zones were not contributing to flow even after stimulation due to high permeability contrast across reservoir flow units. As a result, Multi-stage completion is one of completion designs that initiated to overcome reservoir complexity where it comprises of hydro-mechanical liner hanger packer, open-hole packers, hydraulic anchor and multiple frac ports set and activated as a drop-ball system. This type of completion avoid perforation or cementing process that reduce formation damage; so, it allows wellbore to access to full formation natural fractures and reservoir potential. Moreover, Multi-stage completion permits to select different stimulation technique across zone of interest and reduce well intervention costs. The 4 ½" Multi-stage ball activated sleeve completion (HPHT) which is an alternative strategy to produce from different zone of interest successfully installed, sequentially stimulated and commingle- tested on flow back for two different case studies. Reservoirs are divided into three distinct intervals and acid treated with different stimulation techniques (Acid fracturing & High Rate Matrix Acidizing). The flow tests showed very good results that provide a good evidence for deploying this technology in tight gas and unconventional reservoirs. This paper focuses on designing, installing, and execution phases of MSC of two successful case studies. In addition, spotting the key learnings and critical factors that should follow in the future to guarantee the well performance enhancement and overcome reservoir challenges.