Gazovaya promyshlennost’№ 04 2020

» Model of the intrasalt brine formations that complicate the well drilling at Astrakhan gas condensate field

Hole making in rock salts at Astrakhan gas condensate field is accompanied by emerging of high-pressure concentrated brine, which results in problems during the drilling. Analysis of causes of complications in well development in 2000–2018 revealed that 80 % of upset scenarios flow from lack of data on the localization of brine-risky levels in the area and sequence. The study proposes the novel hypothesis on the geomorphological correlation of salt domes with the spatial arrangement of brine-bearing formations. The mechanism is proposed to explain the anomalously high and low formation pressures. Also, the new geological model is created to find the brine-risky formations remotely. The model will use the seismic data to reveal the zones where the brine is likely to emerge during well drilling at the Astrakhan gas condensate field. The results are advised to use when planning and managing the design and subsalt drilling activities at productive sediments of Astrakhan, Kovyktinskoye, and some other oil and gas fields, which will enhance the feasibility of design and engineering decisions.

Keywords: BRINE, BRINE-BEARING FORMATION, BRINE EMERGING, INTRASALT FORMATION, DRILLING, MODEL, FORECAST, ASTRAKHAN GAS CONDENSATE FIELD.

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» Using proxy models of gas deposits for production optimization

Advanced technologies of geological, hydrodynamic, and integrated simulation of formations are widely used in oil and gas field development. Such models enable resolving the optimization tasks to ensure the approved production levels and parameters. Detailed (small-scale) geotechnical models are the most widespread ones. However, it is not feasible to use them for rapid multivariant calculations of gas field process parameters because they are quite time-consuming, labor-intensive, and require specialized software. The article proposes an approach based on using gas asset proxy models created on the basis of the material balance model. The modeling method is described: zonal gas deposit drainage layout with a description of the aquifer effect by introduction of the enlarged water well. The paper covers the matching parameter selection algorithm when matching the actual development and forecast history. Evaluation of the relative permeability effect on simulation quality is an important part of the study. The obtained data have shown that the incorrect accounting of the relative permeability results in a considerable error in critical parameters of the proxy model (drained reserves, well interference coefficients) and thus significantly affects the forecast gas and water production rates. It is shown that using the proxy model enables resolving the short-term (up to one year ahead) real-time optimization tasks with an accuracy close to detailed hydrodynamic models.

Keywords: PROXY MODEL, HYDRODYNAMIC MODEL, OPTIMIZATION CALCULATIONS, MATERIAL BALANCE, HISTORY MATCHING.

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» Petrophysical models of complex reservoirs (exemplified by oil-gas plays of the Yamal Peninsula)

Detailed examination of complex terrigenous reservoirs is not possible without developing an advanced petrophysical model (mathematical model of petrophysical interconnections) based on the integration of all the available geological and geophysical information. The article provides the algorithm for developing a petrophysical model applied to the facilities of the Yamal Peninsula. Geological and geophysical data is analyzed for four oil and gas bearing regions: Malyginskiy, Tambeyskiy, Nurminskiy, and Yuzhno-Yamalsky. Also, the core data and well logging results were taken into account within Albian-Cenomanian, Neocomian-Aptian, and Lower-Middle Jurassic oil-gas plays of 12 fields. Over 20 000 core samples are examined from different hydrocarbon deposits. The study considers the key factors (geological conditions of sedimentation, physical and petrophysical properties of rocks, well drilling technology) that contribute to forming the storage area of reservoir rocks and, consequently, determine the type of petrophysical interconnections model. The development stages of petrophysical interconnections models are outlined. The most significant parameters are revealed that determine whether the rock can be a commercial reservoir. Three-dimensional dependencies and multi-dimensional cross-plots are obtained to assess the reservoir properties of non-uniform reservoirs.

Keywords: PETROPHYSICAL MODEL, WELL LOGGING, RESERVOIR CLASSIFICATION.

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» Calculation of horizontal well flow rate exemplified with development of Tarasovskoye oil field

» Improving the organizational and methodological work safety management mechanism (exemplified by implementation of large investment projects)

The high injury level in construction companies entails improving the approaches to high-efficiency occupational health and safety management at all levels during the implementation of investment construction projects. High level of differentiation and specificities of contracting with organizing a multi-level structure of subcontractors involved to solve specific, often highly specialized tasks, require using general unified industrial safety standards for all those involved in construction. Those standards shall allow neither ambiguities nor misunderstandings and take into account the specific features of the activities and exposure to hazardous and harmful factors. To that end, Gazprom Neft, SIBUR, and NIPIgazpererabotka have initiated the implementation of the project on developing a single regulatory and methodological basis for unified approaches to large investment projects' management and structure. The project also aims to prepare for the shift to proactive subcontractor management system for facilities both under operation and under construction.

Keywords: OCCUPATIONAL HEALTH AND SAFETY, MANAGEMENT SYSTEM, REGULATORY AND METHODOLOGICAL SUPPORT, INDUSTRIAL SAFETY.

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» Examination of thermal protection properties of personal cold-protective equipment for distal segments of hands and legs and determination of their application range

» Stress-strain state characteristics of pipeline wall under the internal pressure, bending, and torsion

Main oil and gas pipelines are exposed to various stresses and loads during the operation. The article provides the research results for the stress-strain state of a pipe under separate and combined loads: internal pressure of the pumped product, vertical bending, and torsion. A pipe fabricated of 14KhGS steel (outer diameter 325 mm, wall thickness 8.5 mm, length 3 m) was investigated. Experiments were conducted at the laboratory bench that loaded the pipe with vertical bending and torque. Strains were measured using the strain gage sensors on the outer surface of the pipe, in its cross-section angular coordinates from 0 to 180°, at 15° intervals. In each of 13 examined zones, we installed a strain gage rosette with four strain gages to measure hoop, longitudinal, and angular strains at +45 and –45°. The angular strains were calculated using the strain gage rosette theory. Components of stress were calculated using the formulas of inverse generalized Hooke's law. To study the effect of internal pressure on the development of the stress-strain state of the pipe, the thick cylindrical shell theory was applied. The superposition principle was applied to evaluate the stress-strain state of the pipe under combined loads. Based on the study results, dependence diagrams were plotted for hoop, longitudinal, and shear stresses, as well as von Mises stresses at angular coordinates in different loads (internal pressure, bending, torsion, internal pressure + bending, internal pressure + bending + torsion). It is found that maximum von Mises stress at combined loads is located at an angular coordinate of 90°. In this case, according to the maximum strain energy theory, the pipeline side element is the most vulnerable to destruction.

Keywords: GAS PIPELINE, PRESSURE, BENDING, VON MISES STRESS, TORSION, STRESS-STRAIN STATE, STRAIN GAGE SENSOR.

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» Method for evaluation of pipeline erosion rate

» Deep-water gas pipelines: Scientific support of the projects

Offshore gas pipelines are increasingly being used today. However, some features in their design and construction led to a range of new scientific and technical tasks to ensure their trouble-free operation. The article considers the key issues associated with deep-water pipelaying with the focus on their stability against the propagation and local buckling. The equations are provided for calculating the critical buckling pressure. The paper also outlines the resulting evaluation criterion for pipeline stability. It also introduces the design of thickened insert for localization of propagation buckling. The paper considers the problem of deep-water gas pipeline stability during laying, shows the main methods for offshore pipeline laying, their advantages and disadvantages. The comparative analysis is given for loads, stress, and strain in S-lay and J-lay of a gas pipeline. The calculation results are provided for stresses in a sagbend section of a pipeline during the lay in different inclination angles. Also, recommendations are given to reduce the load on a pipeline and to determine the minimum radius of its curvature, depending on the horizontal movement of the vessel. The considered results were applied in some offshore gas pipeline projects.

Keywords: DEEP-WATER GAS PIPELINE, LOCAL BUCKLING, PROPAGATION BUCKLING, LAY METHOD, LAYING METHOD, STABILITY.

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Gazovaya promyshlennost’ № 04 2020

Read in this issue:

GEOLOGY AND GAS FIELDS DEVELOPMENT

GAS AND GAS CONDENSATE EXTRACTION

OCCUPATIONAL AND INDUSTRIAL SAFETY

Repair and diagnostics of main pipelines, compressor plants and pumping stations

Gas and gas condensate transportation