The global climate crisis forces the search for new ecological sources of energy and mining methods. Space mining can solve those problems, but, first, wide geological surveying space missions using drilling methods are necessary. Additionally, drilling methods will be important in geological, life searching, geoengineering, and many other studies of extraterrestrial objects. Space is becoming a new area of possible drilling applications. Designing future space drilling missions requires adapting drilling technologies, not only to the conditions of the space environment, but also to the economic and technological realities of the space industry. The possibility of constructing low mass coring devices with energy consumption below 100 W was investigated in this paper. Minimization of energy consumption and mass of a coring is essential for the device to be used in space missions, when lander instruments supplied by low power electric battery are expected to work reliably and the launch cost (depending of mass) at an economically acceptable level. Some similar devices investigated for the future space missions are known from papers listed in the references. To answer whether or not it is possible to build such devices, the authors performed initial drillability tests. The obtained results are presented in this paper.
SeLecTeD meThoDS of meASuriNg DriLLiNg muD SeTTLiNg** 1. IntRodUCtIon The mud circulation in a rig is sometimes compared to the blood circulation in a living organism because of the vital functions it plays. Drilling mud is important for a number of reasons, e.g. stabilizes wellbore walls, prevents uncontrollable inflow of reservoir fluid and consequently eruption, removes cuttings, lubricates and cools down the drill elements. It can be also used for driving the bit, analogous to the downhole drives. Changes of the mud pressure can be used for sending information. Drilling muds are frequently composed of many constituents to provide specific physical and chemical properties, adjusted to definite wellbore conditions. Frequently the composition is not revealed by the producer and remains confidential [1]. The basic criterium classifying drilling muds is its base, i.e. liquid phase [2, 3]. Water-and oil-based muds dominate in oil industry. The former can be easily prepared and maintained therefore they are most commonly used. They can be adjusted to definite wellbore conditions. Much more expensive are oil-based muds. Muds containing liquid phase usually have to be weighted to provide the appropriate density. For this reason a densifying agent is added in a proper proportion. Among the most frequently applied densifiers is barite-barium sulfate BaSO 4 of density 4.3 to 4.6 g/cm 3. This additive is delivered to the rig site in a powdered form (API grain size). Water-or oil-based muds usually have a suspended solid phase in them (liquid solutions of solid phase). Such systems tend to undergo a settling process which brings about a negative effect. Prior to settling the mud has uniform density. At all depth intervals of the wellbore the mud density remains constant. Pressure exerted by the column of fluid h high is expressed by the formula (1).
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