Expandable Resin for Countering Severe Loss Circulation

Abstract

AbstractOne of the main reasons why loss circulation is difficult to remedy is the lack of knowledge about accurate fracture width and depth encountered while drilling, leading to an improper selection of suitable plugging materials that can adapt, in both volume and shape, to effectively plug a wide range of fractures with unknown dimensions. Traditional, non-reactive particulate/fiber based or settable fluid, types of loss circulation materials (LCM), when applied in insufficient quantities, cannot effectively seal a high permeability zone. The LCM described in this paper is however expandable in nature. This expandable nature of the resin can help the LCM adapt in volume to effectively seal a wide range of fractures with unknown dimensions. Volume adaptability is introduced in the LCM through in-situ generation of gas due to the decomposition of a gas generating compound.The novel expandable LCM comprises of a resinous material, a gas producing agent, surfactant and an activator. The resinous material in presence of a gas producing agent, surfactant and an activator is designed to expand under downhole conditions and help to cure severe losses. Different LCM compositions comprising varying concentrations of resin material, a gas producing agent, surfactant and an activator have been described in the paper. Two different resins were used in the study. The resins were mixed in different ratios and the impact on gelling time was investigated. An aliphatic chemical activator was used in the study. The effect of this activator on the gelation properties of the resin was investigated. The effect of temperature on the expansion of the resin in the presence of gas producing agent was also investigated.The expandable LCM starts to generate gas in-situ under wellbore conditions. Laboratory testing has been performed to quantify the % of expansion of the resin at different temperatures. It was observed that the rate of gas generation is faster at higher temperatures. The expandable LCM is designed so as to have a controllable gelation time under a variety of downhole conditions to allow accurate placement of the LCM inside the wellbore without premature setting of the fluid. It was shown that the gelation time of the treatment composition could be controlled by adjusting the concentration of the activator. The system is designed so as to give a predictable and controllable pumping time, ranging from a few minutes to several hours at over a wide range of temperatures.