Evaluation of High-Temperature Recrosslinkable Preformed Particle Gel for Fluid Loss Control during Drilling

Lost circulation has become one of the biggest challenges that drilling engineering faces during drilling, especially at high-temperature reservoirs. The consequences of lost circulation can vary from an economic aspect as well as a safety aspect. In this paper, the capability of a novel high-temperature recrosslinkable preformed particle gel (HT-RPPG) is evaluated to see whether it can be better used to control severe and total losses. The HT-RPPG is injected in the form of dispersed swellable gel particles, but it can self-crosslink to form a strong bulk gel after being placed in target zones. The sealing pressure and plugging efficiency of the HT-RPPG were evaluated utilizing a core flooding test. Various impacting factors were investigated, including the swelling ratios, fracture widths, and bentonite concentrations. Results indicated that HT-RPPG is an excellent material that can be used to control the severe loss of drilling fluids in fractured reservoirs with temperatures up to 130°C. The recrosslinked RPPG could withstand pressure up to 1,077 psi/ft for fractures up to 2 mm, and permeability was reduced more than 107 times.