In the current drilling technology today pointed out the problems associated with the instability of work downhole drilling motors , they stop, short service life of working devices (WD) and accidents (lapels, destruction elements DDM) layout of the drill string (DS). In particular, the timing of the engines, depending on the size and operating conditions, ranging from 90 to 235 hours. Failures DDM according to drilling companies “Gazprom drilling” and “CSA Deutag» – from 5 to 12 per year; which leads to long-term recovery efforts in the well, or the complete elimination of the latter. From the practice of using found that about 50% of all failures associated with DDM wear working devices are a pair of friction rubber-metal (stainless steel rotor – rubbersteel-stator).
Solving complex scientific and engineering problems calls for a considerable amount of experimental research and testing in order to study and obtain an objective assessment of the impact of various factors on the change in the studied parameters. In this regard, we install II-5018 was reconstructed to study the tribological properties of the “elastomer – rinsing liquid – the metal” as applied to the interaction of the friction pair “stator – rotor” in the PDM. To this end, as close to reality friction pair “rubber – metal”. The article discusses the problem of choosing the methods of laboratory tests, which must meet the requirements and standards applicable standards and regulations to carry out standardized tribological tests and studies to determine the physical and mechanical properties of rubber.
The results of complex investigations in the field of studying the processes of friction and wear of friction pairs elastomer-metal with the purpose of improvement of a technique of study of tribological aspects of the power section of screw downhole motors.
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.
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).
DEVELOPING THE LABORATORY STAND FOR SIMULATION AND WORK SETTINGS RESEARCH OF HYDRODYNAMIC WELL GENERATOR VALVE
Impact on the near-well and remote reservoir areas by wave methods are becoming more common in the practice of drilling and well operations, both in Russia and abroad. The most effective and positive impact on the near-well formation zone (NWFZ) has elastic vibrations of the low frequency range. Such fluctuations in the designated frequency range provide vibro-wave method of influence on NWFZ.
Vibro-wave impact is implemented by different constructions of hydrodynamic well generators (HWG) which use hydraulic power of the pumped into the well process liquid for its work. The design of laboratory stand (Figure 1) and the procedure for researches on it has been developed for determining the flow rate regime areas of HWG and the degree of influence of various constructional parameters of HWG on their flow rate regime areas.
The construction and operating principle of the multi-purpose laboratory stand has been described in this paper. The stand allows to research the work settings of the new devices, as well as comparative tests of existing down hole equipment up to modern level with digital recording results to the personal computer. The method for determining the parameters of the hydrodynamic pulses of hydrodynamic well generators has been proposed. The investigations of identifying areas of flow rates of the hydrodynamic well generator are presented.
During the conducted studies it’s established that the amplitudes of the pressure oscillations generated by HWG tend to increase with increasing fluid pressure. The intensity of this increase is determined by the flow rate of the working fluid passing through the HWG. During bench tests there is a conclusion that the increase of the amplitudes of pressure oscillations can be characterized by a tangent function of the approximating line slope.
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.