Analysis of the efficiency of drilling petrocom solution for primary exposure of production formation at the Bolshoy Olkhovsky field named

. When developing gas and oil wells, a special drilling fluid is used. This composition helps to solve many problems, so the use of this solution is a necessary process in field development. The current article discusses PetroCom drilling fluid, its composition, performance and properties.


Introduction
Drilling fluids used in drilling practice, as a rule, can have different density, viscosity, composition and properties not only within the same field, but also in the conditions of drilling one well.There is no universal drilling fluid that would ensure trouble-free drilling of the entire well, since lithology, physical and mechanical properties of rocks, temperature, pressure, etc. change with depth.Therefore, the choice and optimization of its composition and properties should be based on the geological and technical conditions of well drilling, taking into account environmental safety and economic efficiency.
Drilling mud is a complex dispersion system, which is a combination of a dispersion medium and a dispersed phase of various composition.It can be a suspension (water and solid phase), an emulsion (water and hydrocarbons), an aerated liquid (water, surfactant and air).The solution circulates inside the drill pipes and the annulus, cleaning the bottom of the well from the rock destroyed by the bit and transporting it to the wellhead.In this case, the solution must have a certain viscosity and density, which is limited by the absorption and hydraulic fracturing pressure.
The drilling fluid used to drill in the formation is the first working fluid to come into contact with the reservoir.Traditionally used water-based muds can lead to severe formation fouling.Many service companies considered this issue and came to the conclusion that it is necessary to develop special drilling systems and separate them into a separate category, for which the main task, when opening productive formations, is to preserve natural reservoir properties.At the same time, drilling fluids must have satisfactory rheological parameters and transport capacity and ensure trouble-free drilling.

Materials and methods
To ensure the preservation of the permeability of the productive reservoir, the properties and composition of the drilling fluid for opening the productive formation are subject to the following requirements: «ISK «PetroEngineering» LLC has developed a system of inhibited biopolymerpotassium chloride drilling fluid PetroCom, which is designed for primary drilling of a productive formation.The PetroCom system creates a thin, elastic, impermeable cake on the walls of the well.Penetration of the fluid into the rock is limited by the high viscosity of the filtrate containing the biopolymer.These processes are accompanied by the formation of an impenetrable thin screen of crushed marble chips and a modified starch reagent.Components such as Xanthan Petro xanthan biopolymer and Petro Safe reagent, a liquid water repellent produced according to the developer's specifications, provide the technical result.
Due to the preliminary selection of fractionated calcium carbonate, as well as control of its content during well drilling, this drilling fluid system provides minimal filtration, which also causes a small zone of penetration of the mud filtrate into the bottomhole zone.Taking into account the small annular gaps when drilling horizontal wells and the optimal rheological properties of the drilling fluid, there should be no problems with ensuring the removal of cuttings.
The formulation and properties of PetroCom drilling fluid are presented in tables 1-2.To prevent possible absorption, the density of the solution should not exceed 1.19 g/cm3.
Before starting drilling, it is necessary to prepare at least 90 m3 of drilling mud.The recommended screen mesh size is 24-38 mesh.The use of a sludge separator is not recommended.
The effectiveness of PetroCom's drilling fluid is that it can be used in almost any reservoir.This is beyond the scope of prototypes, the solution has increased thermal stability, has low water loss, provides better wettability of the rock with hydrocarbons, which improves the flow of oil into the well.

Results
Specialists of «ISK «PetroEngineering» were able to create a drilling fluid that does not pollute the oil reservoir and, in terms of its characteristic features, surpasses similar systems on the drilling fluid market in Russia and abroad.Known prototype fluids are subject to more rapid thickening during drilling, which leads to an undesirable increase in hydraulic resistance in the circulation system and a decrease in the efficiency of fluid circulation during well cleanout.In addition, the prototypes are unstable to temperature effects.
According to the results obtained, the productivity of wells after drilling, where this fluid was used, was higher than that of traditional polysaccharide (starch) potassium chloride drilling fluids.The solution has proven its main function in practice: it does not pollute the reservoir, so the initial productivity of oil wells is higher.− it is also necessary to strictly monitor the level of the drilling fluid in the top-up tank to prevent underfilling of the well when lifting the tool; − strictly and in a timely manner to control the parameters of the drilling fluid and, with minor deviations, to process it without allowing sharp jumps in parameters (density, relative viscosity, fluid loss).

Conclusion
Thus, the analysis of the results of using the PetroCom drilling fluid showed its high efficiency in terms of maintaining the reservoir properties of the productive formation and trouble-free well drilling.

Table 1 .
Recipe and need for chemicals

Table 2 .
Recommended solution parameters

Table 3 .
Calculation results