DETERMINATION OF ELASTIC DEFORMATION OF SPRING DEFLECTION OF THE SEALING UNIT

The article discusses the definition of elastic deformation - deflection of the spring of the sealing unit of the Christmas tree valve. Using variational methods, the optimal solution of the spring deflection of the gate valve sealing unit was determined. It is proved that the obtained formulas give rather accurate results of the spring deflection of the valve sealing unit.

Detachable Joint Sealing Based on Leakage Duct Hydraulic Resistance

The types of detachable fixed joints with elastic and plastic sealing are considered, their disadvantages are indicated. A new design of the sealing unit for fixed and movable joints is presented, eliminating these disadvantages. The tightness of the structure is ensured by increasing the hydraulic resistance of the leakage channel of the sealed medium, which has a cross-section in the form of an equilateral triangle. The channel is spirally placed in the contact zone of the sealing surfaces, the inlet and outlet of which are located along the inner and outer diameters of the mating surfaces, respectively. Expressions for calculation of the proposed type of joints for real conditions of its use are presented.

Contact Deformation of the Pipeline Sealing Unit

The features of the turbine steam line sealing unit stress-strain state are examined on the basis of the usage of a three-dimensional design model of the construction and contacting surfaces. The considered unit consists of the pipeline, a crimp casing consisting of two halves with an outlet in one of them, and a gasket. A mathematical model that takes into account the mechanical loads caused both by the internal steam pressure on the steam line wall and by the casing fasteners tightening has been formed. This model also includes contact interaction in the sealing unit on the contact surface of the pipeline, the upper and lower halves of the casing. This contact problem solving method, based on the application of the finite element method, is proposed. The finite element model is based on twenty-unit three-dimensional finite elements with three degrees of freedom at each unit. Eight-unit contact finite elements were used to describe contact and sliding between surfaces. Contact conditions are taken into account with the penalty method usage. The verification of the model and the software that implements the proposed method is carried out by comparing the calculation results and experimental data obtained on the physical model of the pipeline. The physical model was made from a low-modulus material with full geometric similarity and the same ratio of the elastic moduli of materials as in a real object. The stress-strain state of the sealing unit of a real pipeline in a three-dimensional setting was determined and the most stressed zones in the unit, which require increased attention during the design and operation of pipelines and their connections, were identified. The developed approach and software make it possible to determine the contact pressure for the horizontal joint flanges of highly stressed cylinder bodies of powerful steam turbines, which helps to avoid a large number of expensive experimental studies.

The use of simulation modeling in the design of elements of annular preventers

One of the main elements of control over wells in the process of their construction is the blowout equipment, which includes annular preventers. This also applies to wells that provide degassing of coal veins to reduce their gas dynamic activity. Modern technology of work requires expansion of the functionality of the sealing unit of the annular preventers with the simultaneous provision of its operational characteristics. Determining the necessary durability of seals for different operating modes is the study of their stress-strain state. The paper deals with the possibility of using simulation modeling in the annular preventers design situations and within the study of the armature geometry influence of the sealant fittings on its stress-strain state. The method of determining the material constants to realize the Mooney-Rivlin model has been proposed. The behavior of low-density rubber in software product has been described by the finite element method. The aggregation error of experimental and theoretical studies is 5%. Therefore, the preconditions and the possibility of using simulation modeling in the design of annular preventers devices with increased operational characteristics have been created and confirmed.

IMPROVEMENT OF THE CONSTRUCTION AND COMPUTER DEVICE INVESTIGATION FOR THE PROCESSING OF BLOWOUT-PREVENTION HARDWARE EQUIPMENT

The research deals with the problem of blowout equipment test for tightness before implementation. The indicated equipment includes a stem, a system of pipelines with valves and a control system. The classic test procedure requires a mobile pumping installation that provides a pressure of 35 MPa.The cost of such tests is rather high. For testing without a pump unit, a design of a device for increased tightness has been developed, including a sealing unit of the mouth from the main column and a piston unit for creating high pressure in the test volume. Generation of a high pressure occurs by lifting the piston with a winch, mounted on the well. Disadvantages of the previously proposed design of the device are as follows. There is a considerable friction between the steel moving parts of the sealing unit. Mostly these are the pairs of a plug and a cup, and a chuck and a cone. Tightness is provided by rubber ring sleeves. Exceedence of axial load on cones causes destruction of sealing rings. The authors of the article improved the design of the sealing unit in the following way: a ball thrust bearing was seated between the ends of the pressure plug and the bottom cup and as a result the sliding friction was replaced with sliding friction. On the outer surfaces of the opening cones in contact with clamping blades, it is proposed to paste a tissue antifriction material of type Nafthlene or equivalent. The friction coefficient in such pairs is next lower order than in steel to steel pairs. The computer model of the device has been created in the Solid Works environment. The computer researches of the loading process of components of the sealing unit in the simulation program based on the finite element method were performed. As a result of the research, recommended values ​​of the axial force, required to create a screw pair of a stem and a plug for sufficient radial axial deformation of elastic cuffs with the simultaneous non-admission of their destruction were identified. Also, the design dimensions of the pressure cups of the device were optimized, namely, the mutual axial placement of the end face, which presses on the cone, and the tapered belt, compressing the sealing ring. The determination of these parameters by an experiment is a long and expensive process.

Seal potential of shale sequences through seismic anisotropy: Case study from Exmouth Sub-basin, Australia

Sedimentary rocks with sealing potential can cap a reservoir by impeding the upward movement of hydrocarbons. An effective seal should have three qualifying factors of geometry, integrity, and capacity. Mapping seismic horizons and faults across the area of study reveals much about the geometry and integrity of the sealing unit. Capacity, however, depends on capillary pressure measurements of core and cuttings samples. Modeling capacity of seals away from and between wells has traditionally involved simple gridding techniques or association with most likely geologic or seismic facies. We have developed a different approach in using seismic data and applying it to the evaluation of sealing potential. Shales are the most common seals in petroleum systems. Seismically, well-developed shale units that have undergone compaction are likely to be anisotropic and are typical vertical transverse isotropic media. Seismic data with suitable acquisition parameters were processed to extract [Formula: see text] and Thomsen’s parameters of weak seismic anisotropy, tied to the vertical seismic profile data at wells. The spatial distribution of [Formula: see text] has shown a good correlation with capillary measurements of well samples. Hence, 3D modeling of epsilon was used as a weight factor to guide the capillary pressure ([Formula: see text]) values away from the wells. Capillary pressure values were then mapped on the fault planes to high grade the analysis of sand-shale juxtaposition. Our results helped to explain the distribution of successful wells and dry holes within the study area.