Perm Journal of Petroleum and Mining Engineering (Jun 2019)
Studies of hydgocarbon-based muds for drilling-in productive formations
Abstract
Purpose of the work is to increase effectiveness of drilling-in productive formations while using hydrocarbon-based muds. Several studies were performed within the work: evaluation of aqueous phase contents on alteration of rheological parameters of muds; evaluation of kind of gilsonite in hydrocarbon-based muds on its structure rheological and filtration properties. Well completion using hydrocarbon-based muds is most efficient for purpose of preserving filtration and capacity properties of productive formation, but such muds are expensive enough. With purpose to reduce cost of such systems emulsion muds were developed, becoming more used during drilling-in, but for their efficient usage it is necessary to select components composition with reason, as even slight variations in quantity of reagents responsible for system stability, may lead to emulsion coalescence and phase separation. Drilling-in productive formation using emulsion mud may lead to many complications, lessening reservoir to well connectivity or reducing reservoir permeability. One of such complications is loss of circulation. Mud used to drill-in formation should be made so that to practically avoid decline natural permeability of productive zones, provide for excellent hole cleaning and be easily conditioned. Various materials exist, such as gilsonite (natural asphalt) or bitumen and amine-treated lignin, and also polymeric fillers used to prevent thieving due to reducing filtration and formation of impermeable mud cake. Studies made within the work have demonstrated effectiveness of application of natural and synthetic asphalts in hydrocarbon-based muds, and also opened new directions for further studies with purpose to expose regularities appearing with change of components composition.
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