RU2424269C1 - Emulsion solution on hydrocarbon base - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: emulsion solution on hydrocarbon base contains wt %: diesel fuel 14.98-84.55, organophilic bentonite 0.39÷4.26, "Emulsifier MR" 0.83-2.38, "Oil-wetting agent ABR" 0.015-0.73, water phase mineralised with potassium, or sodium, or calcium chloride 1.5-36.73, 20 %-solution of poly-isobutylene with molecular weight 20000 in industrial oil I-20A 0.33-3.81, calcium oxide 0.39-2.38, mineral filler - chalk or barite - the rest.

EFFECT: formation of process emulsion solution on hydrocarbon base facilitating reduction of dispersive ability of drilled out clay slime and improved filtration-capacitive characteristics of pay at initial exposure and at well killing.

2 cl, 5 tbl

Description

The invention relates to the oil and gas industry, in particular to hydrocarbon-based drilling fluids (ERU) used in well drilling, and to process fluids used during underground repairs.

A well-known hydrocarbon-based drilling fluid containing oil, emulsifier, organophilic bentonite, an aqueous phase of varying degrees of mineralization and additionally a tertiary amine (SU 1788000 A1). The disadvantage of this solution is the limited heat resistance. The value of filtration after heat treatment at 150 ° C reaches 19 cm ³ even with an organophilic bentonite content of 9.9%.

A well-known hydrocarbon-based drilling fluid, comprising a hydrocarbon base, synthetic fatty acid, sodium hydroxide, a weighting agent and atactic polypropylene and paraffin as a structure former (RU 2208035 C1). The disadvantages of this solution are low heat resistance (up to 100 ° C) and intolerance to the effects of water due to the use of a water-soluble sodium salt of a fatty acid as a thickener and emulsifier.

It is known that polyisobutylene with a molecular weight of 175000-200000 is used in the composition of emulsion solutions on a hydrocarbon base (Use of oil-soluble polymers to improve the quality of hydrocarbon-based solutions. / K.Sh. Ovchinsky, I.Z. Fainshtein, R.K. Rakhmatullin, etc. // Construction of oil and gas wells on land and at sea. - 1992. - No. 1. - P.15-19), their use is limited to temperatures of 100-120 ° C. More heat-resistant (up to 200 ° C) is an emulsion solution containing tire renegade (SR) as an oil-soluble polymer (see ibid.). However, this solution is not technologically advanced, since SR dissolves only at temperatures above 250 ° C.

The closest technical solution is "Blocking fluid" ZhG-IER-T "(RU 2357997 C1), consisting of the hydrocarbon phase - oil or diesel fuel, organophilic clay," Emulsifier MP "or" Emulsifier Neftenol NZb "," Water repellent ADB ", mineralized sodium, or potassium, or calcium chlorides of the aqueous phase and the filtration regulator - chalk. To achieve the required density in the composition of the liquid, barite can be used. The disadvantages of this fluid are:

- low heat resistance (up to 150 ° C),

- not a wide range of possible densities, limited to a range of 0.9-2.2 g / cm ³ ,

- high dispersing ability in relation to clay sludge, which makes it ineffective to use when drilling shallow wells in unstable clay deposits,

- filtration characteristics (filtration value, filtrate viscosity) that negatively affect the conservation of reservoir productivity when opening or damping.

The objective of the invention is to develop a technologically advanced emulsion solution based on a hydrocarbon-based thermostable up to 200 ° C, with a possible density range from 0.84 to 2.3 g / cm ³ , which reduces the dispersibility of drilled clay sludge and improves the filtration-capacitive characteristics of the reservoir during the initial opening and killing wells.

The essence of the invention lies in the fact that a hydrocarbon-based emulsion solution containing diesel fuel, organophilic bentonite, "Emulsifier MP", "Water repellent ADB" mineralized with potassium chloride, or sodium, or calcium, aqueous phase, the mineral filler is chalk or barite, different the fact that it additionally contains a 20% solution of polyisobutylene with a molecular weight of 20,000 in industrial oil I-20A and calcium oxide in the following ratio of components, wt.%:

Diesel fuel 14.98-84.55 Organophilic Bentonite 0.39-4.26 "Emulsifier MR" 0.83-2.38 "ADB Water Repellent" 0.015-0.73 Indicated aqueous phase 1,5-36,73 The specified solution of polyisobutylene 0.33-3.81 Calcium oxide 0.39-2.38 Barite or chalk Rest

Moreover, calcium oxide is introduced immediately before the specified aqueous phase. For the preparation of ERUO, materials manufactured by industry can be used. For example, as organophilic bentonite - "Orbent-91" according to TU 2458-079-17197708-2003; which is the product of the interaction of bentonite clay with a quaternary ammonium salt;

as an emulsifier - “Emulsifier MR” according to TU 2458-097-17197708-2005, which is a hydrocarbon solution of esters of fatty acids and triethanolamine;

as a water repellent agent - “ADB Water Repellent” according to TU 2483-081-17197708-2002, which is a hydrocarbon solution of condensation products of fatty acids and amines.

As the aqueous phase, depending on the drilling conditions, saturated aqueous solutions of potassium, or sodium, or calcium chlorides are used, which do not significantly affect the technological properties of the solutions.

As the polyisobutylene with a molecular weight of 20,000, the oil-soluble polymer “NRP-20M” can be used, manufactured according to TU 2483-028-54651330-09 or TU 2458-012-94310333-2008 and representing a 20% by weight solution of the indicated polyisobutylene in industrial I-20A oil.

The introduction of polyisobutylene with a molecular weight of 20,000 (in the form of “НРП-20М”) in the ERUO allows increasing the thermal stability of the solution due to the fact that polyisobutylene molecules, being in the interphase layer, contribute to an increase in the density of protective shells on water droplets and contribute to an increase in the aggregative stability of the emulsion. In addition, the thickening dispersion medium ERUO (diesel fuel), “NRP-20M” increases the structural and rheological properties of the solution, reduces its filtration and increases the viscosity of the filtrate, which favorably affects the preservation of the filtration-capacitive properties of the reservoir. This is especially important if you need to use for drilling or killing wells ERUO with the lowest possible density, since the input "NRP-20M" can improve these performance characteristics without increasing the density of the solution.

An additional input of calcium oxide into the EDFD allows reducing the dispersing ability of the solution, which is especially important when drilling shallow wells in unstable clay deposits.

To prepare the solution does not require special equipment or heating.

ERUO is prepared as follows.

In a hydrocarbon medium, polyisobutylene is dissolved, and then organophilic bentonite is introduced and dispersed under a high-speed stirrer.

An emulsifier, calcium oxide and a prepared in advance mineralized aqueous phase are sequentially introduced into the obtained organo-clay polymer suspension. In this case, the reaction of the transition of calcium oxide to hydroxide occurs before the blocking of water globules by an emulsifier and a polymer. The emulsion is intensively mixed at 9000-13000 rpm to achieve a constant value of the indicator of electrical stability.

To obtain a solution with a density of less than 1.0 g / cm ³ regulate the phase ratio of the emulsion (hydrocarbon - water) in the direction of increasing the hydrocarbon content. To obtain a solution with a density of more than 1.0 g / cm ^{3, the} initial emulsion is weighted with chalk or barite with simultaneous dilution with diesel fuel and treatment with “ADB Water repellent”. Experiments have established the relationship between the required density of the solution, the amount of unloaded emulsion, barite or chalk, diesel fuel for diluting the solution and water repellent.

In terms of the starting materials, the ERU compositions of various densities are presented in table 1.

The basic composition for weighting is an emulsion with a density of 1.0 g / cm ³ . To weight the solution to a density of 1.2 g / cm ³ it is possible to use chalk or barite, over 1.2 g / cm ^{3 the} solution is weighted only by barite. If necessary, weighting with barite chalk in the composition of the solution is not introduced.

The prototype is prepared using a similar technology with the same number of main components, without the addition of “НРП-20М” and calcium oxide.

Depending on the problem being solved, the invention is illustrated by the following examples.

Table 1 The compositions of the solutions of various densities, wt.% Component Name The density of solutions, g / cm ³ 0.84 0.9 1,0 1.20 1.20 1.8 2,3 Diesel fuel 84.55 68.61 49.82 36.31 39.56 22.10 14.98 NRP-20M 3.81 2,8 1.68 1.23 1.26 0.61 0.33 Organobentonite "Orbent-91" 4.26 3.33 2.0 1.46 1,50 0.72 0.39 "Emulsifier MR" 1,075 2.11 2,38 1.73 1.90 1.43 0.83 Calcium oxide 2,38 2.23 2.0 1.46 1,5 0.72 0.39 Water phase 1,53 17.56 36.73 30.46 31.72 16.65 9.3 "ADB Water Repellent" 0.015 0,03 0.15 0.27 0.23 0.69 0.73 a piece of chalk 2,38 3.33 5,0 27.08 - - - Barite - - - - 22.33 57.08 73.05

To compare the line of possible densities of the proposed solution and the prototype, we prepared three samples of solutions with a density of 0.84 g / cm ³ , 1.0 g / cm ³ and 2.3 g / cm ³ according to the recipe compositions shown in table 1.

The quality of the solutions before and after thermostating at 200 ° C was evaluated by the following property indicators: density (ρ, g / cm ³ ), electrical stability (E, V), plastic viscosity (η _pl , MPa · s), static (CHC _1/10 , dPa) and dynamic (τ _о , dPa) shear stress.

The results are presented in table 2.

table 2 The properties of the proposed solution and prototype before and after thermostating №№ Property metrics Suggested Solution Prototype ρ, g / cm ³ η _pl , MPa · s τ ₀ , dPa CHC _1/10 , dPa E, B ρ, g / cm ³ η _pl , MPa · s τ ₀ , dPa CHC _1/10 , dPa E, B one 0.84 22 37 15/18 1910 0.85 3 3 0/0 1830 2 1,0 40 80 33/36 837 1,0 fourteen 57 16/16 430 3 2,3 81 220 108/114 1134 2,3 68 195 87/90 333 Thermostating at 200 ° C one 0.84 13 32 12/15 1830 0.85 3 3 0/0 837 2 1,0 27 134 21/24 626 1,0 3 6 0/0 125 3 2,3 90 225 54/60 456 2,3 Parameters immeasurable (flocculation) 13

Analysis of the presented results shows that the proposed solution can withstand temperatures of 200 ° C in the entire range of declared densities, as evidenced by the indicators of structural and rheological properties and electrical stability. The prototype with a density of 0.84 g / cm ³ does not have viscoplastic structural properties, which does not allow its use as a washing liquid. This is due to the fact that in such systems, components (organophilic bentonite, aqueous phase) are used to increase the viscosity and structural parameters of the solution, which simultaneously increase the density of the solution to the declared value of 0.9 g / cm ³ . A prototype with a density of 1.0 g / cm ³ also loses its structural and rheological properties after heating at 200 ° C.

The nature of the change in the rheological properties of the proposed solution and the prototype of this density in the mode of stepwise heating on a high temperature rheometer OFITE Viscometer Modell 1100 allows you to determine the temperature limits of their possible application (table 3).

Table 3 Indicators of the rheological properties of solutions at various temperatures Temperature ° C Suggested Solution Prototype η _pl , MPa · s τ, dPa η _pl , MPa · s τ, dPa 49 29th 64 16 40 80 19 57 fourteen 39 110 16 93 eleven 39 140 fifteen 123 9 12 150 fourteen 127 3 3 200 12 93 - -

At a temperature of 150 ° C, the prototype loses its viscosity and structural properties.

In a solution (according to the prototype) with a density of 2.3 g / cm ³ after temperature control at 200 ° C (table 2), flocculation of the solution occurs (rheological properties become immeasurable, E = 13 V), due to the insufficient strength of the interfacial layers of the emulsion only due to the emulsifier and direct contact of barite particles with the precipitated aqueous phase of the solution.

The influence of the proposed solution and prototype on the preservation of the permeability of the reservoir (for example, solutions with a density of 1.0 g / cm ³ ) was carried out on an improved core research facility in accordance with RD 39-0147001-742-92 “Methodology for a comprehensive assessment of the quality of opening of productive formations, completion of wells and selection of working fluids to improve the quality of drilling. ” The temperature of the experiment is 85 ° C. During the experiment was determined by filtering (F, ^cm3 / 30 min), the rate of steady filtration (V, m / s) and the coefficient of permeability reduction (P,%) defined as the ratio of core permeability of oil before and after exposure to the solution. After this, the filtration radius R _f and OP were determined by calculation (the ratio of the actual productivity of the formation to potential).

The research results on two types of cores with different permeability (K _m . Μm ² ) are presented in table 4.

Table 4 The influence of the type of solution on the performance indicators of the opening of reservoirs Type of solution Breed group K _m , μm ² F, ^cm3 / 30 min V _f , m / s β _f ,% R _f , m OP Suggested Solution I 0,00649 0.32 2.1 · 10 ^-7 72.5 0.26 0.98 Prototype I 0,00753 0.75 2.8 · 10 ^-7 67.0 0.35 0.94 Suggested Solution II 0.0172 0.38 3.3 · 10 ^-7 75.6 0.26 0.98 Prototype II 0.0169 1.15 6.4 · 10 ^-7 57.0 0.36 0.93

Analysis of the presented results allows us to evaluate the proposed solution as the best system from the point of view of preserving the natural permeability of the reservoir.

The dispersing ability of the proposed solution and prototype was evaluated by the clay slurry of the Orenburg NGDU in accordance with the Rolling Test method.

This technique involves introducing into the solution an equal amount of sludge of a certain degree of dispersion, holding it for a predetermined time in autoclaves with horizontal rotation at a certain temperature, followed by sieving the solution through a sieve with dimensions corresponding to the lower dispersion plate. Then determine the percentage of undispersed sludge. The experimental conditions and the results obtained are presented in table 5.

According to the test results, it was found that clay rocks disperse much worse in the proposed solution than in the prototype solution. The inhibitory effect of the proposed solution is due to the presence of calcium oxide in its composition and improved filtration characteristics.

Table 5 Evaluation of the dispersing ability of the proposed solution and prototype Indicators Suggested Solution Prototype Field Orenburg oil and gas field Well number 1080/2 Type of sludge Clayey Weight of sludge, g 20,0 The degree of dispersion, mm 0.7-2.0 The temperature of the experiment, ° C 65 Rolling time, h 5 Amount of non-dispersed sludge, g 17.02 9.95 The percentage of non-dispersed sludge,% 85.1 49.65

Claims (2)

1. A hydrocarbon-based emulsion solution containing diesel fuel, organophilic bentonite, "Emulsifier MP", "ADB Water-repellent", the aqueous phase mineralized with potassium chloride or sodium or calcium, the filler is chalk or barite, characterized in that it is additionally contains a 20% solution of polyisobutylene with a molecular weight of 20,000 in industrial oil I-20A and calcium oxide in the following ratio, wt.%:
Diesel fuel 14.98-84.55 Organophilic Bentonite 0.39-4.26 "Emulsifier MR" 0.83-2.38 "ADB Water Repellent" 0.015-0.73 Indicated aqueous phase 1,5-36,73 The specified solution of polyisobutylene 0.33-3.81 Calcium oxide 0.39-2.38 Barite or chalk rest 2. The emulsion solution according to claim 1, characterized in that the calcium oxide is introduced immediately before the specified aqueous phase.