Perm Journal of Petroleum and Mining Engineering

The territory of Azerbaijan located in the central part of the Mediterranean mobile belt is characterized by high seismicity, mud volcanism, widespread slumps and contrast character of modern vertical and horizontal movements occurring in the sedimentary part of the geological section. The paper contains results of studies of the features of the connection of earthquakes and tectonic movements that cover the Mesozoic and Cenozoic intervals of the geological section. The work is carried out with a complex interpretation of data by the method of the common depth point (CDP) of seismic survey; well logging; vertical seismic profiling (VSP) performed on the study area and its periphery; observations of seismic for the period from 2003 to 2016. A comprehensive interpretation of the data allow to construct several seismogeological profiles in a direction perpendicular to the axis of the Caucasian mountain structures. Several profiles of a similar direction (SW-NE) were compiled along the Caspian Sea as well. The geological section is split into stratigraphic and lithologic-facies intervals based on CDP seismic data using VSP and well logging data. Analysis of dynamic and kinematic parameters of the seismic wave field recorded on the area of interest showed that a tectonic process began in the Mesozoic (possibly Paleozoic) period, continued to the end of the Cretaceous, somewhat decreased (unloaded) at the beginning of the Cenozoic and then continued in the Quaternary period. The seismic activity of the region confirms that the process continues nowadays. Based on the results of a joint interpretation of seismology and CDP seismic survey data it was established that shallow-focus earthquakes in the foothill regions of Azerbaijan occurred and occur under the influence of global tectonic processes that create a prolonged geodynamic tension in the upper part (to the depth of 12 km) of the sedimentary complex of deposits. Joint interpretation of CDP seismic survey data and seismology indicates the presence of a collision zone in the area of the junction of the South Caspian depression and Absheron-Pribalkhanskiy threshold, interpreted by some researchers as a subduction zone. The analysis of geological and geophysical data accumulated during the period from 1985 to 2015 tells about the need to revise the tectonic map of the oil and gas bearing regions of the republic and its connection with the seismic map of the territory.

Physical and mechanical properties of polymer cement slurries and cement stone are studied. The goal of the work is to improve the quality of completion of productive formations by development of polymer cement mixtures with improved structural and mechanical characteristics of a cementing slurry and cement stone. During the completion a special attention is paid to the preservation of well cement stone quality. So, there is a brittle fracture of the cement stone occur because of the dynamic loads caused by cumulative and bullet perforation, as well as the torpedoing of casing strings. Using such methods of well completion a cement stone can be destroyed both in perforation intervals and in places of bridges that separate productive layers from aquifers. The consequence of that opening is the accelerated growgh of water cut of wells. Despite the high technical level of new types of perforators, they are not widely used in drilling of oil and gas wells because of the large time and metal consumption of the work performed and, consequently, high financial costs of their use. It is known that the integrity of the cement stone is ensured at perforation during the transition of the coagulation structure of a cement suspension to crystal one. For a normal cement slurry (water/cement = 0.5) that moment occurs relatively quickly (7-15 h), which is not enough for perforation operations. In order to modify the properties of a cement mixture the compositions of cation-active surfactant (catamine) and non-ionic polymer (polyvinylpyrrolidone) were chosen. Results of experimental studies show that the input of these agents into the composition of a cement mixture leads to an increase in spreadability of a cement slurry (more than 25 cm by the cone of Azerbaijan Scientific Research Institute), time of its bondability, strength of a cement stone for compression (200 % after 28 days of hardening) and bending (250 %), adhesion of cement stone to metal (by 80 %) and time of coagulation structure setting. In addition, plastic properties of the developed cement slurry are retained for more than 19 hours. The influence of the agent (defoamer T-66) on the rate of cement stone strengthening is determined. It is shown that input of a nonionic high molecular polymer reduces the rate of the formation of crystal structure in a cementing mixture.

According to audit data about 75 % of residual oil reserves of Perm region fields are characterized by water cut of well production of more than 50 %. Development of the methods for reducing water inflow is one of the priority areas of research. The paper presents the results of an analysis of available sources for reasons of oil water cut and methods used to eliminate water inflow. A detailed classification of remedial cementing jobs is displayed. The review of chemical methods allowing to block the water inflow in the bottomhole and remote zone of the reservoir is given. It was established during the analysis that studying of polymeric materials for remedial cementing jobs is a relevant direction. An analysis of domestic and international experience shows that the use of polymeric materials to eliminate water inflows allows to increase oil recovery up to 85-90 %. Such parameters as structure (large caverns or cracks of small diameter) and localization of water inflow, temperature, reservoir pressure and formation permeability, characteristics of reservoir fluids dictate individual requirements for the polymer composition in terms of rheology, polymerization kinetics, strength characteristics and thermal stability. The most urgent task of waterproofing works in the Perm region is the elimination of watered intervals and redistribution of fluid flows into undeveloped less permeable sections of the geological section. In this regard, technology to reduce water inflow with the help of gels with a high penetrating power and high strength after the completion of polymerization are in demand at the deposits of the Perm region. Taking into account the analysis, the technology of polymeric blockage of water inflow using polyacrylamide (PAA) was adopted as the most suitable for conditions of reservoirs of Perm regions. Laboratory tests are carried out to study and select polymer compositions for remedial cementing jobs at the fields of the Perm regions, including the polymerization process depending on the composition pH. The change in viscosity of the polymer composition during the time with a PAA content of 0.75 % and chromium acetate of 0.02 % is studied. As a result of testing the polymer based on PAA, it was found that viscosity of a polymer composition increases with increasing temperature and concentration of the crosslinking agents.

In the conditions of the Verkhnekamskoe field of potassium and magnesium salts unconventional in terms of thickness sylvinite seams are involved in the mining. That requires methodological support and new technological solutions. One of the possible directions in the excavation of sylvinite seams of unconventional thickness is the use of drilling and blasting. A method for calculating the safe geomechanical parameters of the chamber development pattern was developed in order to justify the possibility of drilling and blasting excavation of sylvinite seams of unconventional thickness. The paper presents theoretical calculations for determination of the parameters of a chamber development pattern taking into account the requirements of current regulatory documents. That ensures geomechanical safety during drilling and blasting mining of sylvinite seams of unconventional thickness as well as during mining of sylvinite seams of unconventional thickness in combination with mashinery mining of seams with conventional thickness. Two options of drilling and blasting mining of sylvinite layers depending on the mining and geological conditions of development, are considered in the paper. The first option considers drilling and blasting excavation by the chamber pattern of one sylvinite seam of unconventional thickness. The second option considers drilling and blasting mining of an unconventional sylvinite reservoir together with a machinery mining of adjacent sylvinite layers that have conventional thickness. Minimum allowable size of the production chamber in the drilling and blasting mining of sylvinite seams of unconventional thickness, design and actual parameters of chambers and inter-chamber blocks are justified according to the requirements of regulatory documents. The procedure for calculation of sizes of the cleaning chambers in drilling and blasting mining and inter-chamber blocks in the joint excavation of sylvinite layers of conventional and unconventional thickness. The method for determination of safe parameters of blasting operations providing the permissible value of the fracturing zone in the soil and roof of the cleaning chambers mined by the drilling and blasting method is presented. Calculations have been performed to determine the fracture radius based on the calculation of explosion pulse and dynamic strength of the salt rocks. Determination of the allowable weight of explosion is done using the value of the displacement speed of the particles in the array. As a result of the studies performed, the safe parameters of drilling and blasting mining of one sylvinite layer with unconventional thickness by the chamber pattern and the sylvinite formation of unconventional thickness together with longwall machinery mining of conventional formation at the mines of Verkhnekamskoe field of potassium and magnesium salts.

At the present stage of production enhancement it is impossible to create absolutely safe working conditions in the oil production mines of the Yaregskoe field, but ensuring acceptable working conditions in the workplace remains one of the most important tasks in the field of labor protection. Yaregskoe is unique oil field in terms of the shaft method of heavy oil mining. An oil shaft is rather a deviation from the general ideas about the mining industry of Russia and the world. The main idea of the thermoshaft method is a decrease in viscosity and increase in oil mobility due to the heating of a formation by coolant injection. The technology used to extract heavy oil has created special working conditions. The majority of workplaces in oil mines correspond to the 3rd class of working conditions (harmful), degrees 3.1-3.3, where the maximum permissible levels of exposure to harmful factors are exceeded in comparison with permissible values. Harmful working conditions entail a consistently high level of occupational disease. The variety of negative factors and possibility of their combined effects on the body with various combinations of the labor process determine the need for an integrated approach to assess the combined effects of negative factors. Today, the assessment of working conditions is carried out in accordance with the Federal Law of the Russian Federation No. 426-FL "On a special assessment of working conditions" and Order No. 33n of the Ministry of Labor of Russia "On approving the methodology for conducting a special assessment of working condition classifier of harmful and (or) dangerous production factors, the form of a report on the special assessment of working conditions and instructions its filling". In a special assessment of working conditions the overall result is affected only by factors beginning with grades 3 and 4 of working conditions. The combined effect of production and labor process factors is represented only by a qualitative assessment. The analysis performed allowed to rank the probability of the impact of factors of a certain class of working conditions on workers of the Yaregskoe oil mines by structural subdivisions. To assess how labor conditions conform normative labor requirements and a degree of impact of deviations from normal values on human body a special point system (usually a six-point system) is used. There is a calculation of professional risks for the underground staff of the Yaregskoe oil mine made based on the "Point assessment of professional risk". Assessment of occupational diseases shows a high risk of obtaining occupational diseases for a group of underground workers of the Yaregskoe oil mine. There is a special risk for workers at mining and oil production sites. The risk is represented in three parameters such as increased noise, vibration and physical overload. An underground miner and road worker are the safest jobs.