DEVELOPMENT OF COMPOSITE ADDITIVE IMPROVES ANTICORROSION AND TRIBOLOGICAL PROPERTIES OF DRILLING WASH SOLUTION
Currently applied technology of drilling oil and gas wells is characterized by problems related to the instability of work of the downhole drilling motors, they stops, short service life of working bodies (WB), accidents – flaps, destruction of structural elements DDM, arrangements of the drill string (DS). The reason for some of these problems is the corrosion. Currently struggle with corrosion includes a number of methods, such as protection at the manufacturing stage of the metal, treatment of the environment to reduce the aggressiveness by introducing corrosion inhibitors. To reduce the effect of corrosion produced corrosion inhibitors or retarders, these agents increase the corrosion resistance DSF, they are one of the most effective means of protection of drilling equipment, drilling and rock cutting tool. The effect of inhibitors due to a change of the surface state of the metal, because of adsorption of the inhibitor or forming with cations of metal sparingly soluble compound. To reduce the negative effects of corrosiveness circulating fluid in the drilling equipment; drilling tubes and rock cutting tools made of high-alloy steels, use of special corrosion-resistant plating compositions. In the industrial environment, in some cases, reducing the loss because of corrosion can be achieved by changing the composition of the medium. Increasing anti-corrosion properties of DCF is one of the most effective means of protection of drilling equipment, drilling and rock cutting tool.
The authors had considered in the article causes destabilization lithified clay rocks (mudstone and claystone-like) and the formation sticking of the bit in unlithified leck in the field of the Timan-Pechora province and Western Siberia on the basis of the literature, own experimental research and field material. Physico-chemical processes of reaction between the contacting surfaces (adhesion) are one of the reasons and in that in both cases. Adhesive interactions in the rock provide stability clay shale which is characterized slabby, thinly laminated structure with exspressed slip plane, the presence of chaotic microcracks and significant amount of debris. The authors give recommendation about integrated use of clay by applying organic and inorganic inhibitor and technical carbon (for example, carbon black), witch increase the adhesive interaction between the individual ratchet of clay rocks on the basis of own laboratory research besides generally accepted methods preservation of stability claystone-like (inhibiting, hydrophobization, wall packing). The probability of forming cake intensifies in haz-lithified clay from plastic deformation clay rock to form a sealing contact with the surfaces of the bit or steel tubes. The authors conducted a complex research in the laboratory, which has allowed to develop a series of recommendations to be considered at the opening of plastic smectite clay. Except for a general increase in lubricating efficiency drilling mud, necessary to limit the content of the colloidal phase (MBT 3.5 kg/m3) in the presence of a potassium chloride at a concentration of not less than 80 kg/m3 to reduce the intensity of the adhesive interactions with the components of the drilling mud and metal surfaces (the formation of the cake).
When drilling oil wells, drill-pipe strings are the main components that constrain reliability and efficiency of drilling rigs. The highest number of drill-string failures is caused by pipe parting. It is suggested that pipe-parting failures are preceded by the formation of a portion having a through-thickness radial lengthwise cut or a notched portion with a smaller cross-sectional area. Neither lengthwise cut nor crack in the rod can be determined using natural frequencies of longitudinal or flexural vibrations, because in the zone of the cut there is no reduction of the area and axial moments of inertia in the rod’s cross section. Therefore, this article deals with natural torsional vibrations of a drill string having damages as a through-thickness radial lengthwise cut and as a lateral notch. It has been found that in the case of the cut or the notch located within the vibration node, natural frequencies do not depend on the lengths of these damages. As the length of the cut or the notch increases, the lower frequencies of natural torsional vibrations will decrease. For the drill-string lengthwise through-thickness cut, changes in the natural torsional vibration frequencies are considerable as compared to similar frequencies for the drill string having a lateral notch. Using two natural torsional vibration frequencies, we can determine the initial coordinate and length of the through-thickness radial lengthwise cut on the drill string. Using three natural torsional vibration frequencies, we can determine the coordinate, length and parameter of the notch.
It article discusses the issues of the location of drill pipe in the curved sections of the wellbore and their interaction with the walls.
The analysis of literature data on the interaction of pipe columns with walls slant wells, mechanisms of the formation of grooves numerical experiments and modeling, which allowed us to draw conclusions with interest for further research and practical workers.
It is shown that the mechanism of developments gutter workings consists of a complex mechanical indentation and fracture of rocks interlocks (classical approach) and fatigue failure due to thermal exposure of the pipe body and locks, and locks to a lesser extent.
Solved geometric tasks required to represent operating conditions of the columns in deviated wells. Defined the basic mathematical relations, which allows to calculate for different sizes of the contact condition of the body of the drill pipe and the borehole wall. Estimated critical situation, namely, the minimum radius of curvature of the wellbore to the beginning of the touch, the contact length of the pipe with the hole wall. Modeled the mechanism of formation of grooves in the feedback castles, estimated effect sizes of drill pipe for critical parameters is complicated by the trunk such as: gutter width, its depth. The article presents the dependence convenient for practical application in field conditions to assess critical conditions of the wellbore, as well as for the optimization of layouts drill string with the goal of reducing accidents and complications in the deepening of the well.
The development of this work will allow in the future to predict the depth of the trench and to revise strengthening evaluation of the drill string.