In high-performance water-based drilling fluids, filtration control is a closely monitored mud characteristic. Several problems have been found that are linked to excessive invasion of aqueous filtrate into a permeable formation. A high filtrate loss often causes thick filter cake formation that lead to tight spots in the hole. Elevated temperatures and fluid loss in deep holes can cause situations such as differential sticking of pipes. At the same time, loss of filtration control catastrophically affects the rheology of the water-based fluid via excessive thickening. Seepage of the filtrate into sensitive shale formations may lead to swelling, sloughing or even cave-in. Filtrate invasion into a production zone can lead to a condition known as water blocking, where the reservoir pressure is not strong enough to drive the aqueous filtrate out of the pores, leading to drastic reduction of oil and gas flow. In this contribution, we explore the synthesis of a novel star block copolymer fluid loss control additive using reversible addition-fragmentation chain transfer (RAFT) polymerization using arm-first approach. The star polymer developed in this work is able to provide superior filtration control performance (3 to 6 times better performance) over commercial additives. In addition, the thermal and mechanical stability of this novel material afforded direct incorporation into drilling mud formulations commonly used in the middle east drilling operations, which led to excellent fluid loss control both at room temperature and high temperature, high pressure conditions with thin filter cakes.

The antioxidant activity of the fruit extract of Habenaria edgeworthii (commonly known as Vrddhi) has been studied against a long lived 2,2-diphenyl-1 picrylhydrazyl (DPPH) radical at room temperature. Green syntheses of Vrddhi fruit extract conjugated gold and silver nanoparticles at room temperature have been reported.