A finite element model, which includes reservoir rock, cement stone, casing, and perforation channels, was developed. The purpose of the study is to create a geomechanical model of the zone around the well, which includes support elements and perforation channels. This model will help predict changes in the productivity coefficient of a terrigenous reservoir and determine the most efficient mode of operation of a producing well. In order to exclude the stress concentration within the casing–cement stone and cement stone–rock, the numerical model applies contact elements. As a result, structural elements slip, while the stresses are redistributed accurately. The numerical simulation of a stress state in the near-well zone was carried out by using the developed model with differential pressure drawdown on the terrigenous reservoir, one of the oil fields in the Perm region. It is shown that the safety factor of the casing reaches roughly 3–4 units. The only exceptions are the upper and lower parts of the perforations, where this parameter is close to one unit. The safety factor of cement stone accounts for 2–3 units. However, parts with its lowest value (1.35) are also concentrated near the perforation channels. In order to analyze the change in permeability, the dependence of the safety factor on effective stresses was taken into account. Therefore, it was found that, in the upper and lower parts of perforations, the stresses decreased, while permeability rose by up to 20% of the initial value. An increase in differential pressure drawdown, on the contrary, can lead to a permeability reduction of 25%, especially in the lateral parts of the perforations. Areas of rock destruction under tensile and compressive forces were identified by using the Mohr–Coulomb criterion. It is estimated that with an increase in pressure drawdown, the areas of rock destruction under tensile force disappear, while the areas of rock destruction under compression increase. After further analysis, it was found that, with the maximum pressure drawdown of 12 MPa, the well productivity index can decrease by 15% due to the reservoir rock compaction.

Various casing perforation methods are used to ensure a hydrodynamic reservoir-to-well connection. However, perforated wells often do not perform satisfactorily during production. This is largely due to a decrease in the permeability of the near-wellbore formation as a result of casing perforation work. Studies and analysis of existing casing perforation methods have shown the effectiveness of abrasive jet perforation. The paper presents the results of numerical modeling to optimize the layout of slot channels during the abrasive jet perforation (AJP) of terrigenous productive object. Geomechanics analysis of the influence the formation scheme and orientation of the slotted channels in the productive layer during abrasive jet perforation on the permeability of terrigenous reservoirs of the oil fields in the Perm Krai was performed. The disadvantages of widespread methods of exposing perforation are described and the advantages of abrasive jet perforation based on geomechanical modeling are revealed. The calculations carried out on the placement of slotted channels showed that the distance between the systems of slotted channels is not important, since they weakly interact with each other in height with standard schemes. It was established that the best placement scheme for jet slot channels is a system of four slot channels shifted along the length of the well to the height of the slot channel with a phasing of 90°. Comparative calculations of the reservoir permeability of the near-well zone for various perforation methods have been performed.

A finite-element scheme has been developed, including a section of reservoir rock, cement stone, casing and perforation channels. It is noted that in order to exclude the occurrence of stress concentrators at the casing – cement stone and cement stone – rock contacts, contact elements are specified in the numerical model, due to this, structural elements «slip», but at the same time, a reliable redistribution of stresses is carried out. Numerical simulation of the stress state of the near-wellbore zone using the developed model with varying depression on terrigenous reservoir for the conditions of one of the Perm Region oil field is carried out. It is shown that the safety factor of the casing is about 3–4 units, with the exception of small areas near the upper and lower areas of the perforations, where this indicator is close to one. For cement stone, the safety factor was 2-3 units and however, areas with its lowest value (1.35), also concentrated near the perforation channels, were note. To analyze the change in permeability, the dependence of this characteristic on effective stresses was used and it was found that zones of reduced stresses and an increase in permeability up to 20% of the initial value are detected in the upper and lower parts of the perforations. With an increase in depression on the reservoir, permeability decreases, especially in the lateral sections of the holes, where this parameter can decrease by 25% of the initial value. Using the Coulomb-Mohr criterion, areas of rock destruction from stretching and compression were identified. It is noted that with increasing depression, the areas of destruction under tensile stresses disappear and the areas of destruction under compression increase. An analysis of the change in the productivity coefficient depending on the depression showed that when creating a maximum depression on the 12 MPa formation, the productivity coefficient of the well can decrease by 15% due to compaction of the reservoir rock caused by an increase in effective stresses.

Well construction is a complex process that requires meticulous attention at every stage, and well casing with subsequent cementing is no exception. The future efficiency and trouble-free operation of a well are contingent upon the quality of the cementing job. Therefore, effective wellbore preparation and the application of advanced cementing materials are of paramount importance. This paper presents laboratory study results evaluating the efficacy of an integrated approach developed by the authors. This approach involves preparing the wellbore for cementing using a system of spacer fluids tailored to the specific geological, mining, and technological conditions of drilling operations, followed by placement of a self-healing cement slurry into the annulus. This slurry can autonomously repair damage to the cement sheath integrity caused by various mechanical loads incurred during well construction, development, production, and enhanced oil recovery (EOR) operations. The methods for assessing the effectiveness of this integrated approach, utilizing newly developed procedures and laboratory setups, are also described. The developed spacer fluid system enables a 281.5% increase in cement-to-casing bond strength under laboratory conditions compared to conventional spacer fluids. Furthermore, the proposed self-healing cement can restrict the flow of mineralized formation water through 150 μm channels.

The article discusses a current problem of import substitution of rotary steer systems for directional and horizontal drilling. It is noted that the imported Point-the-bit systems are characterized with high performance, but their use is limited. The Perm National Research Polytechnic University is developing a domestic rotary steer drilling system, which key non-standard element is the control board for the submersible part of the telemetry subsystem. The authors selected and justified the use of the following components of the board: the 1640RS4U microcontroller, RS 485/RS 422 (5556IN2T) transceivers, Wika MH 2 pressure sensor, 1487UD1U operational amplifier, MDM10 1V05TUP DC/DC converter. The accuracy class and the number of printed circuit board layers are determined. A functional diagram is presented of the control board designed for use in a domestic rotary steer drilling system.