Geology. Geophysics. Drilling
The article presents a complex of offshore drilling platforms of the Joint Venture “Vietsovpetro”, in which a Jack-up Drilling Complex plays an important role. As in world, in Vietnam Jack-up Drilling Complex is used more often than all other types of plants due to the ease of operation, reliability, economy, and especially because of the specific working conditions and the depth of the sea. The technical characteristics of the Jack-up Drilling Complex used in JV «Vietsovpetro» correspond to all the necessary international requirements.
Comparison of plants with platforms drilling in the Caspian Sea is given. Proceeding from this, the direction of Drilling Complex development for JV «Vietsovpetro» was proposed. Due to its wide field of application, the semi-submersible floating drilling rig is universal, it is planned to operate in JV “Vietsovpetro”.
The physico-chemical properties of the Unifloc polymer sample provided by VNIIBT (Moscow) were studied. And also the influence of this powdered reagent on the basic properties of clay solutions used in the Noyabrsk oil and gas region of Western Siberia was studied. The preparation is prepared by polymerization and alkaline saponification of acrylic acid. The reagent is designed to reduce the filtration and stabilization of clay solutions for drilling wells, as well as for sedimentation of suspended particles in sedimentation tanks and water storage facilities. Reagent Uniflok 4 class, produced in the Republic of Uzbekistan.
The investigated sample of Unifloc reagent results in an effective reduction of the filtration index, both artificially prepared from a benthic powder solution, and the one that was produced in the well directly when drilling a well in the November region. Acceptable concentrations of Unifloc reagent in clay solutions are in the range of 0.1-0.3 %. With a higher concentration of Unifloc reagent, clay solution thickens.
When drilling a well for a conductor in the November region, the Unifloc polymer concentration can be increased to 0.3-0.5%. And to control the filtration properties of the drilling mud when drilling wells under the production column, it is sufficient to adhere to 0.1 % Unifloc.
This Unifloc polymer is sensitive to salts of divalent and trivalent ions, so it is suitable for the treatment of fresh solutions alone. It should also be excluded from contact with a cement mortar containing Ca, Mg salts, since clay solution may be destroyed.
The new sample of the Unifloc reagent differs from the earlier received reagent batches from Uzbekistan in the November region with higher quality. Thus, the filtration properties of drilling fluids decrease more efficiently with a lower increase in rheological properties.
The article presents the results of a study of the composition of petroleum bituminous rocks of the Alimbai field located in the Zhylyoi district of the Atyrau oblast to the north-east of the city of Kulsary (Western Kazakhstan). On the territory of the Republic of Kazakhstan, according to experts, reserves of natural bitumen are 1 billion tons, and petroleum bituminous rocks – over 15-20 billion tons.
The purpose of this work was to study the organic components of petroleum bituminous rocks of this field as an additional source of fuel, energy and chemical resources. Samples of oil bituminous rocks of different depths were taken for the study.
As the results of the analysis showed, the yield of the organic part of the investigated deposit ranges from 3.4 to 13.7% by weight. Natural bitumens of the Alimbai deposit are characterized by a content of oils from 57.8% to 71.3% by weight. In connection with the increase in the depth of occurrence of oil bituminous rocks, a decrease in molecular weight from 587 to 476 amu is observed.
It is shown that the content of paraffin-naphthenic and monocycloaromatic hydrocarbons is much higher than that of bi- and polycycloaromatic hydrocarbons.
The distribution of hydrocarbons by fractions shows the predominant content of paraffin-naphthenic hydrocarbons and alcohol-benzene resins with a low content of asphaltenes and benzene resins.
The obtained results show that even within a small thickness of the rock there are processes of migration of organic matter by analogy with secondary oil migration processes.
The results of physico-chemical studies of reagent K-100 and laboratory analysis of the basic properties of bentonite suspension and natural clay solution taken from a well being drilled in the Noyabrsk oil and gas region of Western Siberia are presented. The reagent K-100 was examined in the concentration range of up to to 3%.
Reagent K-100 is a plugging polymeric additive for liquidation of interformational overflows. The reagent K-100 is manufactured at the Tyumen Plastics Plant “Uralchimplast”. With the industrial application of K-100 reagent in clay solutions, the density of the solution and colloidal content of the clay fraction were observed to be high.
Aqueous solutions with K-100 reagent additives practically do not reduce the surface tension at the kerosene boundary and exhibit low inhibitory properties with respect to the clay slurry of the Noyabrsk oil and gas region of Western Siberia. By the amount of liquid emitted during the swelling of the clay powder, the K-100 reagent is observed to be inferior to other known inhibitors. It is also ineffective for use in qualitative perforation of terrigenous productive horizons; therefore, it is more expedient to be used in composition with other swelling inhibitors, hydrophobic agents, surface active agents and surfactants
The reagent K-100 is observed to form gel-like mixtures with salts of divalent metals. Additions of the reagent in clay solutions actively dilute the solution; the structural and rheological properties become minimal, the pH level increases and flocculation does not occur. Peptization of the clay phase is intensified due to increase in the pH level of the clay solutions
In geophysics, one of the most important areas isgeothermy – science about the study of the thermal field of the Earth. One of the main problems of geothermy is to determine the undisturbed temperature of rocks. The geothermal field parameters (natural rock temperature, geothermal gradient, heat flux) can be used as search attributes of oil and gas deposits. Knowing the natural temperature of rocks is also necessary for wellbore thermal data interpretation. In borehole thermometry, the geothermal distribution as the unperturbed natural rock temperature is the background in the detection and analysis of temperature anomalies associated with productive layers and casing integrity damage. Today, there are no generally accepted methods for determining the unperturbed temperature of rocks. The methods used in practice have a number of problems and allow only to estimate approximately the natural temperature of the rocks. When drilling, the temperature field in the surrounding rocks varies and it takes a considerable time to restore it. This process can continue from a few days to several months-in the case of deep wells, so the natural temperature of the rocks can be measured directly only in a small amount of long time of idle wells.
The known methods for determining equilibrium temperature of rocks are analyzed in the article. A new method based on recording the non-stationary temperature in the well after stopping drilling and determining the equilibrium temperature of rocks based on the use of a simulator of non-stationary temperature in drilled wells is proposed. The mathematical model of the simulator, the formulation of inverse problems and algorithms of their solutions are discussed.