RU2733766C1 - Drilling mud with plug-in solid phase petro plug - Google Patents

Abstract

FIELD: oil, gas and coke-chemical industries.

SUBSTANCE: invention relates to oil and gas industry, in particular, to self-regulating inhibiting calcium drilling mud used in drilling wells under difficult conditions. Drilling fluid contains the following, wt. %: biocide Petro Cide 0.03-0.05; oleophilic lactin S-Drill Block 0.35–2.0; xanthan biopolymer Xanthan Petro L 0.28–0.35; potassium chloride 3.0–13.0; plugging 3.0–10.0; Petro Lube lubricant - 1.39–3.0; antifoaming agent Petro Def 0.05–0.08; different-fraction microcalcite 6.0–2.3; citric acid 0.14–0.24; polycarboxylate lignin S-Drill Cl 0.0–0.8; caustic soda 0.0–0.02; modified starch Petro Starch U 0.0–2.5; starch reagent S-Drill St 0.0–2.0; sodium chloride 0.0–14.0. Drilling fluid can additionally contain cement plugging in amount of 17.0–20.0 wt. %.

EFFECT: technical result is prevention of talus and rock slopes, reduced probability of initiation of flushing fluid absorption due to minimizing effect of pulsating pressures on walls of well, high inhibitory capacity with respect to clay shale, possibility of performing operations to eliminate absorption of flushing fluid without involving third-party organizations for installing cement bridges and, as a result, considerable time saving.

1 cl, 2 dwg, 4 tbl, 2 ex

Description

The invention relates to the oil and gas industry, in particular, to self-regulating inhibiting calcium drilling fluids used when drilling wells in incompatible (difficult) conditions.

The drilling mud is suitable for drilling in intervals prone to rock formation (mudstones, coals, dolomites, etc.) associated with the absorption of drilling fluid.

Known self-regulating inhibiting calcium drilling fluids containing soluble calcium salts, gypsum, lime (calcium hydroxide) as a source of calcium.

Known alumina-gypsum drilling mud containing calcium ions as carriers of calcium 0.2-0.5% wt. and gypsum 1.5-1.8% wt., potassium alum (KAl (SO ₄ ) ₂ ) 0.1-0.3% wt., structurant bentonite brand Medium B 1-4% wt. ., potassium hydroxide 0.03% wt, filtration regulators Osnopak 0.1-0.4% wt, Amilor R-122 1.2-3.0% wt. (patent No. 2516400, IPC S09K8 / 20, publ. 05/20/2014).

The disadvantage is that the use of potassium alum assumes the presence of free sulfate ions in the drilling fluid.

Known lime-based drilling mud based on a colloidal mass, containing an alkaline electrolyte, calcium hydroxide, water, thinners KSDB (concentrate of sulphite-yeast mash), KSSB (concentrate of alcohol stillage sulfite), lime is a source of calcium ions, as a clay stabilizer - sodium aluminate ( RF patent No. 1211274, IPC S09K7 / 02, publ. 25.07.1995 g).

The disadvantage is that the content of impurities in the form of water-soluble carbonates in industrial sodium aluminate requires an increased consumption of lime. Due to the need for preliminary mixing of the KSDB, the time for preparing the drilling mud is significantly increased. The solution has low rheological parameters and, as a result, insufficient waterproofing properties.

Closest to the proposed invention is a cement drilling mud containing cement PCT-50 as a source of calcium ions to inhibit clay deposits - 3.4% wt., An inhibitor of shale aluminum sulfate 0.0-0.4% wt., A structurant clay powder PBMA 8.0-8.3 wt.%, Rheology regulators FHLS-M 1.4-5.0 wt.%, PAC-NV 0.5-1.0 wt.%, Modified Multistar starch 0-1 wt.%, Microcolmatant Sulfobit (sulfonated asphaltene) 1.5-5.0 wt.%, Alkalinity regulator - potassium hydroxide 0.0-0.4 wt.%, Sodium hydroxide 0.2-0.23 wt.% (Patent RU 2 687 815 C1 , IPC C09K 8/20, published on May 16, 2019).

The disadvantage of the prototype is that the composition contains both cement and PBMA clay powder, as a result of which the rheological parameters of this system are at a significantly high level, which can lead to a limitation of the flow rate of the drilling fluid during drilling and affect the rate of penetration. Also, the disadvantages include the fact that the inhibition of shale is provided only by Ca ^{2+ ions} entering the solution with cement.

The essence of the invention

The drilling fluid includes the Petro Cide biocide, S-Drill Block oleophilic lignin, Xanthan Petro L xanthan biopolymer, potassium chloride, grouting cement, Petro Lube lubricant, Petro Def antifoam, mixed microcalcite, citric acid and, if necessary, polyninicarboxylate , caustic soda, starch modified by Petro Starch U, starch reagent S-Drill St, sodium chloride in the following ratio of components, wt%:

Biocide Petro Cide 0.03-0.05 Oleophilic Lignin S-Drill Block 0.35-2.0 Xanthan Petro L Xanthan Biopolymer 0.28-0.35 Polycarboxylate Lignin S-Drill Cl 0.0-0.8 Potassium chloride 3.0-13.0 Backfill cement 3.0-10.0 Microcalcite, different fraction 6.0-22.3 Lubricant Petro Lube 1.39-3.0 Antifoam Petro Def 0.05-0.08 Lemon acid 0.14-0.24 Caustic soda 0.0-0.02 Modified starch Petro Starch U 0.0-2.5 Starch reagent S-Drill St 0.0-2.0 Sodium chloride 0.0-14.0 Water rest

The main objective of the present invention is the use of a unified formulation of drilling mud with plugging solid phase for the construction of inclined and horizontal wells in sections with incompatible mining and geological conditions - absorption zones and unstable intervals prone to talus and collapse.

The technical result is to reduce the likelihood of the occurrence of initiated losses of drilling fluid, and to strengthen the walls of the well in areas with debris and collapses, as well as to eliminate losses of drilling fluid in the event of their occurrence without engaging a service for cement slurries. Reducing the time to eliminate lost circulation.

During drilling, the Petro Plug drilling fluid forms a filter cake on the borehole walls with increased strength properties in comparison with similar filter cakes of traditionally used polymer clay, polysaccharide carbonate and other types of water-based drilling fluids.

An increase in the strength of the filter cake formed on the borehole wall in the drilling fluid is achieved by introducing special oil well cement instead of the traditionally used components of the solid phase: fractional calcium carbonate and clay. The concentration of oil well cement in the drilling fluid is 50-100 kg / m ³ .

An increase in the concentration of cement in the solution to 200 - 300 kg / m ³ results in the formation of a rubber-like substance, which is used to eliminate high-intensity losses of drilling mud in case of their occurrence.

The activity of oil well cement in the composition of the drilling fluid is regulated by the content of lignin-based components, which allows maintaining the “brittle” indicator Gel (SNS10min / SNS10sec <1.5) and preventing an increase in thixotropic properties. Also in this regard, the rheological properties of drilling mud with plugging solid phase can be described by the power-law model of fluid flow (Ostwald), which is characteristic of clay-free polysaccharide drilling muds.

Description of the main stages of using Petro Plug drilling fluid in well drilling:

1) Drilling of the interval from the beginning of the section is carried out on drilling mud prepared on the basis of the "basic formula" with a cement content of 50 kg / m ³ ;

2) Approaching the potential absorption zone during drilling, additional treatment of the drilling fluid with cement to a concentration of 100 kg / m ³ is carried out - “working recipe”;

The filter cake formed on the wellbore walls when drilling with a "working formulation" of a plugged solid phase mud minimizes the occurrence of induced losses due to its greater strength. Also, the degree of influence of pressure pulsations on open cracks is reduced, which prevents their further increase.

3) Elimination of lost circulation.

If drilling fluid is absorbed during drilling, then on the basis of the "working solution" (from the circulation), a part of the volume is taken - 10-20 m ³ as the basis for the preparation of the clogging pack (depending on the absorption intensity and the size of the exposed zone). Next, the pack is processed with cement to a concentration of 250-300 m ³ with the addition of inert fillers with selected size fractions. The obtained viscoelastic composition (VES) is pumped into a drilling tool with an activated circulation sub using a cementing unit and is pushed with a working drilling fluid to be pumped into the absorbing formation.

After the injection of the VEG pack, the drilling tool is lifted into the shoe of the previous string or into a safe uncomplicated interval above the “head” of the pack for the time of the crosslinking reaction.

Within a certain time (2-6 hours depending on the concentration of cement, lignin components and cement setting accelerators), gelation and transformation of the viscoelastic mixture into a rubber-like substance occurs in the pore-fractured space of the absorbing interval. After the technological sludge, the tool is run down, followed by drilling out the visco-elastic pack remaining in the well, which has turned into a rubber-like gel.

In case of complete absence of absorption, well deepening continues. If the absorption rate has decreased, then a similar VEG is pumped, but with a set of inert bridging agents of a smaller size.

4) After drilling out the rubber-like gel, some of the reacted cement may enter the circulating working solution. In this case, an increase in the structural and mechanical properties of the flushing fluid can be observed. To bring these indicators within the limits of standard values, either a partial dilution of the "working solution" with a "base solution" with a minimum cement content, or treatment of the "working solution" with components based on lignin is performed.

Features of Petro Plug solution:

• due to the use of the plugging solid phase in the solution, the formed filter cake has increased strength properties, which helps to prevent sloughs and rock falls, and also reduces the likelihood of initiated losses of drilling fluid by minimizing the impact of pulsating pressures on the borehole walls;

• high inhibiting ability in relation to shale due to the presence of Ca ²⁺ and K ⁺ ions;

• the ability to perform operations to eliminate lost circulation of drilling fluid without involving third-party organizations for the installation of cement bridges, which contributes to significant time savings;

The advantages of the Petro Plug solution compared to the prototype:

• The absence of PBMA clay powder in the formulation allows adjusting the rheological parameters of the drilling mud in a wide range of values to ensure the hydrodynamic regimes of well drilling;

• The presence of potassium chloride and Ca ²⁺ ions in the formulation allows for a higher inhibitory ability;

• The formed filter cake on the walls of the well with the plugging solid phase prevents the transmission of hydrodynamic pulsations to the formation, thereby minimizing the occurrence of initiated losses and preventing rock falls and rock falls;

• In case of lost circulation during drilling, the proposed drilling mud after additional cement treatment to a concentration of 200-300 kg / m3 is used as an alternative to traditionally used cement bridges, which leads to a reduction in the time required to eliminate lost circulation.

• Additional inhibition by Na ⁺ and K ⁺ ions.

• Ability to liquidate acquisitions without attracting additional services.

Main parameters of the Petro Plug drilling fluid (tables 1, 2)

Table 1 - Parameters mud Petro Plug (50 kg / ^m3 of cement)

Parameter After cooking After heat aging at 80 ° C for 16 hours 25 50 85 25 50 85 Density, g / cm3 1.09 1.09 Plastic viscosity, cP 13.6 9.4 12.2 12.9 10.1 7.8 BPS, lb / 100 sq. foot 19.7 14.8 13.4 22.0 17.1 15.7 SNS10 sec / 10 min, lb / 100 sq. foot 6.9 / 9.4 5.0 / 5.6 3.8 / 4 9.3 / 14 6.6 / 8.8 5.1 / 5.3 pH 11.8 11.8 Filtration index, ml / 30 min 3.0 2.4 Peel thickness, mm <1.0 <1.0 Filtration rate HTHP 500psi, 85 ° C - 7.6

Table 2 - the drilling fluid parameters Petro Plug (100 kg / ^m3 of cement)

Parameter After cooking After heat aging at 80 ° C for 16 hours 25 50 85 25 50 85 Density, g / cm3 1.13 1.13 Plastic viscosity, cP 18.3 13.1 12.2 15.0 10.9 10.5 BPS, lb / 100 sq. foot 31.6 23.6 20.1 25.2 20.7 18.9 SNS10 sec / 10 min, lb / 100 sq. foot 9.2 / 11.4 6.7 / 7.7 5.7 / 7.2 10/13 7.0 / 9.4 5.8 / 7.1 pH 11.5 11.5 Filtration index, ml / 30 min 2.6 1.8 Peel thickness, mm <1.0 <1.0 Filtration rate HTHP 500psi, 85 ° C - 6.4

The method for preparing the proposed solution is as follows. With stirring, sodium hydroxide is added to the water to obtain an alkaline medium. Then, with stirring, xanthan gum is added to create a structure, stirred for 30-45 minutes, until the biopolymer is completely hydrated. Then, with stirring, polycarboxylate lignin, oleophilic lignin, antifoam, potassium chloride, sodium chloride are introduced in succession. Then cement plugging, microcalcite of various fractions, lubricant (lubricating additive) and citric acid are added.

In tables 3, 4, respectively, the known compositions and properties of the solution are given.

Example 1. 0.02% sodium hydroxide (caustic soda, GOST R55064-2012) is dissolved in technical (tap) water, then 0.35% of Xanthan Petro xanthan gum (TU 2458-007-89593895-2010) is added to the solution and stirred 30 min with a high-speed stirrer until the polymer is completely hydrated. To the resulting solution, 2.0% starch reagent S-Drill St (TU BY 490850780.008-2016) or Petro Starch U (TU 9187-003-89593895-2010), 0.2% Polycarboxylate lignin S-Drill St ( TU BY 490850780.008-2016) and 0.5% Oleophilic Lignin S-Drill Block (TU BY 490850780.003-2016). Add 0.05% Petro Def antifoam (TU 2458-006-89593895-2010) and 0.05% Petro Cide biocide (TU 2458-005-89593895-2010). Then 3.0% of potassium chloride (GOST 4568-95), 5.0% of taping cement (GOST 1581-96) are introduced. Mix thoroughly for 30 minutes. Then 6.0% of microcalcite of various fractions (TU 5743-002-198026-2017), 2.0% of Petro Lube lubricating additive (TU 2458-009-89593895-2013) and 0.2% citric acid (GOST 908-2004 ). Stir until smooth.

Example 2. 0.02% sodium hydroxide (caustic soda, GOST R55064-2012) is dissolved in technical (tap) water, then 0.35% of Xanthan Petro xanthan gum (TU 2458-007-89593895-2010) is added to the solution and stirred 30 min with a high-speed stirrer until the polymer is completely hydrated. To the resulting solution, 2.0% starch reagent S-Drill St (TU BY 490850780.008-2016) or Petro Starch U (TU 9187-003-89593895-2010), 0.2% Polycarboxylate lignin S-Drill St ( TU BY 490850780.008-2016) and 0.5% Oleophilic Lignin S-Drill Block (TU BY 490850780.003-2016). Add 0.05% Petro Def antifoam (TU 2458-006-89593895-2010) and 0.05% Petro Cide biocide (TU 2458-005-89593895-2010). Then 3.0% of potassium chloride (GOST 4568-95), 10.0% of oil well cement (GOST 1581-96) are introduced. Mix thoroughly for 30 minutes. Then 6.0% of microcalcite of various fractions (TU 5743-002-198026-2017), 2.0% of the lubricating additive Petro Lube (TU 2458-009-89593895-2013) and 0.3% of citric acid (GOST 908-2004 ). Stir until smooth.

Similarly, other compositions of the inventive drilling fluid were prepared with different ratios of ingredients. Table 3 shows data on the components of the compositions of the investigated solutions.

Table 3 - Component composition of the investigated solutions Solution composition,
wt. % Item No. 1 2 3 4 five 6 7 8 Caustic soda
GOST R55064-2012 0.02 0.02 - - 0.01 0.01 0.01 0.01 Defoamer Petro Def TU 2458-006-89593895-2010 0.05 0.05 0.05 0.05 0.08 0.08 0.07 0.07 Biocide Petro Cide TU 2458-005-89593895-2010 0.05 0.05 0.05 0.05 0.04 0.04 0.04 0.03 Starch reagent S-Drill St
TU BY 490850780.008-2016 2.0 2.0 - - 1.62 1.58 1.45 1.39 Polycarboxylate Lignin S-Drill Cl
TU BY 490850780.008-2016 0.2 0.2 0.5 0.5 0.41 0.79 - - Oleophilic lignin S-Drill Block TU BY 490850780.003-2016 0.5 0.5 0.7 0.7 0.6 0.6 0.5 0.5 Xanthan biopolymer Xanthan Petro TU 2458-007-89593895-2010 0.35 0.35 0.30 0.30 0.28 0.28 0.33 0.35 Modified starch Petro Starch U TU 9187-003-89593895-2010 - - 2.5 2.5 - - - - Potassium chloride GOST 4568-95 3.0 3 3.0 3.0 13.00 10.28 9.40 9.06 Sodium chloride GOST 4233-77 - - - - - - 14.0 14.0 Backfill cement GOST 1581-96 5.0 10.0 5.0 10.0 4.06 7.91 3.0 6.97 Microcalcite of different fraction TU 5743-002-198026-2017 6.0 6.0 6.0 6.0 19.74 19.78 22.3 20.91 Lubricant Petro Lube TU 2458-009-89593895-2013 2.0 2.0 3.0 3.0 1.62 1.58 1.45 1.39 Citric acid GOST 908-2004 0.2 0.3 0.2 0.3 0.16 0.24 0.14 0.21 Water 80.63 75.53 78.7 73.6 58.37 56.83 47.3 45.10

In the specified drilling fluid, the regulation of the structural and rheological properties is provided by a xanthan biopolymer. A decrease in the biopolymer content leads to loss of the weighting agent. An increase in the concentration of biopolymer leads to an increase in structural and mechanical parameters.

The inhibitory ability of the solution is regulated by introducing oil-well cement within 3-10%, potassium chloride within 0-13.0% and sodium chloride within 0-20.0%. K ⁺ , Na ⁺ and Ca ^{2+ ions} inhibit the rock content of shales.

Citric acid 0.0-0.5% is used as a plasticizer after cement injection.

Regulation of pH is carried out by changing the concentration of sodium hydroxide 0.0-0.05%.

The filtration index is controlled by introducing polycarboxylated lignin 0.5-3.5% and oleophilic lignin 0.1-3.0%.

In the case of foaming after the introduction of lignins, a defoamer is introduced into the solution in an amount of 0.05-0.2%.

The required value of the density of the drilling fluid is provided by the introduction of microcalcite 3.0-30.0%.

Lubricity (reduction of the coefficient of friction) is provided by introducing a lubricant additive of 0.5-8.0%.

The assessment of the main technological parameters of the investigated fluids was carried out by GOST 33213-2014 (ISO 10414-1: 2008) “Monitoring of the parameters of drilling fluids in the field. Water-based solutions ". Under laboratory conditions, the following parameters were analyzed muds properties: the density (ρ, g / cm ^3), filtration rate (PF, ^cm3 / 30 min), the plastic viscosity (PV, mPa · s), dynamic shear stress (YP, lb / 100 ft ² ), static shear stress at 10 s and 10 min rest (GEL 10 sec and GEL 10 min, lb / 100 ft ² ), pH value.

Table 4 provides information on the technological parameters of the investigated solutions.

Table 4 - Parameters of solutions Parameter # 1 # 2 Number 3 # 4 # 5 # 6 # 7 No. 8 Density, g / cm ³ 1.09 1.13 1.08 1.12 1.24 1.28 1.39 1.44 Filtration index, ml / 30 min 2.4 1.8 3.6 3.4 2,3 2.1 1.7 1.8 Peel thickness, mm <0.5 <0.5 <0.5 <0.5 <1.0 <1.0 <1.0 <1.0 Plastic viscosity, mPa⋅s 10.1 11.1 fourteen fifteen 19.0 21 23 25 DNS, lb / 100 ft ² 17.1 21 25 27 29 31 34 37 SNS _{10 '' / 10 '} lb / 100 ft ² 6.5 / 9.0 7.0 / 10.5 6.0 / 8.0 12.0 / 18.0 10.0 / 17.0 11.0 / 19.0 12.0 / 21.0 14.0 / 24.0 pH 11.8 11.5 11.6 11.7 12.0 12.1 11.9 12.2

The density of the inventive drilling mud with plugging solid phase varies over a wide range of values from 1.08 to 1.44 g / cm ³ . The drilling mud filtration rate does not exceed 4.0 ml / 30 min at a pressure drop of 7 atm, while a thin strong filter cake is formed, which prevents the penetration of filtrate into the formations, and also minimizes the effect of pressure pulsations. Rheological parameters (plastic viscosity, dynamic shear stress, static shear stress in 10 sec and 10 min) ensure effective cleaning of the wellbore from the drilled pore during drilling and keep cuttings in suspension in the absence of circulation.

The change in the strength of the drilling fluid gel with an increase in the cement concentration to 250 kg / m ³ and 300 kg / m ³ are shown in graphs 1 and 2, respectively.

The regulation of the "setting" time of the composition used to eliminate losses is carried out by selecting the cement concentration.

Technological parameters of the inventive drilling mud with plugging solid phase make it possible to use it in various mining and geological conditions. In the event of absorption of drilling fluid, this solution can be used to eliminate absorption by additional treatment of a portion of the solution with an additional volume of oil well cement.

Claims (3)

1. Drilling mud, including the Petro Cide biocide, oleophilic lignin S-Drill Block, Xanthan Petro L xanthan biopolymer, potassium chloride, plugging cement, Petro Lube lubricant, Petro Def antifoam, multi-fraction microcalcite, citric acid and, if necessary, polyhydric acid -Drill Cl, caustic soda, starch modified by Petro Starch U, starch reagent S-Drill St, sodium chloride in the following ratio of components, wt%: Biocide Petro Cide 0.03-0.05 Oleophilic Lignin S-Drill Block 0.35-2.0 Xanthan Petro L Xanthan Biopolymer 0.28-0.35 Polycarboxylate Lignin S-Drill Cl 0.0-0.8 Potassium chloride 3.0-13.0 Backfill cement 3.0-10.0 Microcalcite, different fraction 6.0-22.3 Lubricant Petro Lube 1.39-3.0 Antifoam Petro Def 0.05-0.08 Lemon acid 0.14-0.24 Caustic soda 0.0-0.02 Starch modified by Petro Starch U 0.0-2.5 Starch reagent S-Drill St 0.0-2.0 Sodium chloride 0.0-14.0 Water rest 2. The drilling mud according to claim 1, characterized in that it additionally contains plugging cement in an amount of 17.0-20.0 wt.%.

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