Geology. Geophysics. Drilling
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.
THE STUDY OF THE PRODUCTION BATCHES OF THE REAGENT TYLOSE WATER CHEMISTRY AND ENVIRONMENTALLY FRIENDLY LUBRICANT ADDITIVES FLOTATION-OXAL FOR DRILLING FLUIDS
The influence of commercial batch samples of reagent water chemistry Tilose made by the company “Hoechst AG” (Germany) for the basic and special properties of bentonite suspensions and drilling natural polimergranita drilling fluids oil and gas region of Western Siberia. Given information about physical-chemical properties of sodium carboxymethyl cellulose (CMC), a reagent Tylose water chemistry.
Acceptable additive reagent Tilose of water lead to a sufficient reduction of the filtration rate of clay solutions. However, the structural-rheological properties of clay solutions increase less than the reagent Tilose EC-7. Results of the effect of additives reagent Tilose of water in mixed solution (from the waste at the wells, followed by enrichment of bentonite clay solution).
The laboratory findings of the two compared quantities of reagents Tilose of water arrived at different times, comparable in terms of impact on the properties of clay solutions, which indicates compliance with the same synthesis technology and production of the reagent.
Additionally, a study conducted for the joint processing of drilling mud reagent Tylose water chemistry and reagents Nа2CО3, NTF, NGL-11. Natural drilling fluids, selected wells were treated in the polymeric reagent Whom Paz, lubricant additive flotation-oxal, and other Data established solutions were subjected to tempering. In some cases, the solution treated with reagent Tylose water chemistry, reduced structural-mechanical and rheological properties, but the rate of filtration of the solutions after incubation are not increased. In precoat solution treated with reagent NGL-11, increased colloidal clay component of the solution, as it has peptizyme action.
The study is based on the effects of carboxymethyl starch reagent KMK-Bur-N – Carboxymethyl starch reagent KMK-Bur-N is an additive to water-based drilling fluids for regulating filtration, structural, mechanical and rheological parameters in the manifestation of mineralized mineral waters containing Ca ++ and Mg ++ ions. KMK Bur-N reagent is produced according to TU 2262-016-32957739-01 by the company CJSC “Polycell” (Vladimir, Russia). Carboxymethyl starch is a chemical product of the interaction of starch with sodium mono chloroacetate in an aqueous solution of sodium hydroxide. The KMK-Bur-N reagent can also be used as part of process fluids for well completion and workover. Details are given on the physicochemical properties of KMK Bur-N reagent.
The addition of the KMK-Bur-N reagent to the bentonite suspension leads to a decrease in the filtration index, as well as an increase in the conventional viscosity, plastic and effective viscosity, dynamic and static shear stress. In addition, the KMK-Bur-N reagent can also be used for the chemical treatment of water-based natural polymer-clay drilling fluids produced in wells. Acceptable additives of KMK-Bur-N reagent in clay muds are in the range of 0.3-0.5%. Carboxymethyl starches are compatible with carboxymethylcellulose reagents and other reagents that are used to treat water-based drilling fluids in the Noyabrsk region of Western Siberia. Virtually all types of starch reagents, including the chemical product KMK-Bur-N are easily destroyed by acid treatment and subsequently removed from the productive formation in the event of formation damage during drilling or workover of wells.
REASONS EQUIPMENT FAILURE LOWER PART OF MULTISTAGE FRACTURING SYSTEM THE DESCENT INTO THE UNCASED HORIZONTAL WELLS
Today, due to the difficult economic situation in the country and in the oil industry, the development of new wells became ineffective. In recent years, oil companies significantly increase the amount of work on construction and reconstruction of wells in order to intensify and improve the technical and economic indicators. Problem fields with small reserves and low reservoir properties for our country is not relevant until you run out of the rich fountains of giant deposits. However, today, when the depletion of the resource base – a trend that the work on the fields with low-permeability reservoirs has become a serious challenge, require additions of standard methods of developing new approaches and technologies. Therefore, the problem of increasing technical and economic indicators of the exploited wells in recent years has become very urgent. The technology allows the development of the deposit with low-permeability reservoirs, is a multi-stage hydraulic fracturing. Unfortunately, this strategically important area of oilfield services today is controlled by foreign operators and equipment suppliers. Therefore, one of the most important tasks is to develop the country’s own fleet of equipment MGRP that meets modern standards and regulations of the Russian mining companies.
The article analyzes the major domestic manufacturers of equipment for multi-stage hydraulic fracturing particularly marked advantages and disadvantages of the construction. Also revealed the reasons for which there is equipment failure at the bottom of the layout multi-stage hydraulic fracturing.
In the final part of the article the authors propose the bottom of the design layout, which can eliminate equipment failure.
Conclusions and recommendations for hardware developers.