Application of Formation Pressure While Drilling FPWD Technology in Challenging Low Mobility Environment – Case Study from Western Kazakhstan

Abstract

Historically, pressure measurements have been performed with wireline formation tester (WFT) tools. In highly deviated and horizontal wells, wireline tools are drill-pipe conveyed and this operation can be complex and adds significant expenses and operational risks. On the other hand, formation pressure while drilling (FPWD) technology minimizes operational risks at reduced overall cost and results in increased operational efficiency. This is particularly true for highly deviated and horizontal wells. FPWD technology has its own application envelope. Low permeability reservoirs are traditionally considered to be "no-go zone" for FPWD. Reason being nearly all FPWD tools on the market are equipped with a single probe that has a modest flow area. Whenever formation exhibits extremely low mobility, in the order of 0.1 mD/cP or lower, operators prefer to opt for configurations that increase the flow area such as dual packer conveyed on wireline, despite the added cost and conveyance risk. However, proper job planning and real-time data transmission allows to acquire critical reservoir dynamic data with FPWD tool in challenging low-permeability environment in horizontal wells with reduced operational risks. The following paper discusses the first successful application of FPWD technology in horizontal wells drilled in low permeability giant carbonate reservoir located in Western Kazakhstan. It focuses on the approaches taken during job planning and execution, dwells upon the acquired results and offers a methodology on how to optimize the acquisition. It is worth noting that fluid mobility in some stations was below 0.1 mD/cP, making it an extremely challenging environment. Nevertheless, the results acquired in eight wells has proven that FPWD can perform effectively and provide crucial reservoir dynamic data in separate clinoforms and gain insights about reservoir depletion mechanism, which was previously inaccessible due to operational risks related to formation tester tools conveyance in horizontal wells.