Abstract
In any coring job, a common challenge is to maintain good hole cleaning while using a reduced flow rate to prevent washout of the core samples. Without proper hole cleaning, the hole is exposed to cuttings accumulation which may lead to major problems such as induced losses and stuck pipe case. To ensure adequate hole cleaning during the coring operation in a PETRONAS Carigali Sdn Bhd (PCSB) deepwater well, a new multi-cycle circulating sub, Intelligent Circulating while Drilling (iCWD) was utilized.
iCWD was developed primarily to perform losses treatment, isolate hole sections and improve hole cleaning while drilling without the need to pull out of hole, through surface activation. The tool is unique as it does not require a drop ball for activation and can function in a minimum flow rate environment. In a deepwater operation, this is especially useful as the time saved can be translated into significant cost savings. A further advantage with the elimination of ball activation is that the coring operation which also relies on drop ball mechanism is not compromised by ensuring operational efficiency and reducing the risk of losing the core during the recovery.
