RU2436825C1 - Drilling agent for drilling vertical holes (versions) - Google Patents

Abstract

FIELD: gas and oil production.

SUBSTANCE: according to first version drilling agent contains, wt %: bentonite PBMA 6.0-7.0, soda ash 0.1-2.0, caustic soda 0.1-0.5, Givpan 0.2-0.3, Lubriol 1.0, water - the rest. According to the second version drilling agent contains, wt %: bentonite PBMA 5.0, soda ash 0.1-0.5, caustic soda 0.1-0.5, Givpan 0.2-0.3, Kamcel PAC-VV 0.1-0.3, Kamcel PAC-SV 0.1-0.3, Lubriol 1.0, ALS 0.2-0.3, PES 0.1-0.2, water - the rest. According to the third version drilling agent contains, wt %: bentonite PBMA 2.0, soda ash 0.1-0.5, caustic soda 0.1-0.5, Kamcel PAC-VV 0.1-0.2, Kamcel PAC-SV 0.2, Lubriol 1.0, ALS 0.2-0.3, PES 0.1, water - the rest.

EFFECT: accident-free hole drilling under complicated mining-geological conditions, control over pH and removal of ions Ca²⁺ incoming into solution from carbonate rock.

3 cl, 8 tbl

Description

The invention relates to drilling wells, in particular to drilling fluids for flushing wells during drilling.

Well-known solution formulations have mainly been developed for many years for drilling wells under relatively favorable conditions and did not take into account the petrographic composition and morphology of the drilled rocks. Known drilling fluid containing, wt.%: Bentonite - 1 ÷ 2; stabilizer - carboxymethyl cellulose CMC - 0.6 ÷ 0.8; hydrolyzed polyacrylonitrile "uniflock" - 0.1 ÷ 0.2; xanthan biopolymer - 0.08 ÷ 0.10; water repellent - 0.05 ÷ 0.10; aluminosilicate microspheres - 5 ÷ 20; water - the rest. In another embodiment, instead of CMC, the solution contains 1.0 ÷ 1.4 wt.% Carboxymethylated starch instead of CMC (RU 2309970, 2007).

A disadvantage of the known solution is the impossibility of its use when drilling unstable and carbonate rocks. The use of this solution can lead to complications when drilling such rocks, as this solution does not have sufficient density and viscosity that would allow the wells to pass under difficult conditions, and the solution does not contain additives that allow Ca ²⁺ ions to be removed from it during the sinking of carbonate rocks.

Known formulation of drilling mud containing, kg / m ³ : bentonite clay - 30 ÷ 72; soda ash - 1 ÷ 2.5; caustic soda - 0.2 ÷ 0.7; CMC of low viscosity - 0 ÷ 3.5; ICLUB - 3 ÷ 8; ICD - 0.5 ÷ 3; IKSTAB or GRINDRIL - 2.6 ÷ 4.5; IKPAN-SL - 2.5 ÷ 4.5; IKPAN-RL - 1.2 ÷ 2.5; water - the rest (RU 2231534, 2004). This solution, although it takes into account the possibility of drilling unstable rocks, however, also due to its rheological properties, it cannot guarantee trouble-free drilling in difficult geological conditions.

Known drilling fluid containing wt.%: Bentonite clay - 2.0 ÷ 3.0; carboxymethyl cellulose - 0.1 ÷ 0.15; starch - 1.0 ÷ 2.0; reagent for regulating electrical resistivity - propylene pentamers - 1.0 ÷ 5.0; carbonate weighting agent - 5.0 ÷ 8.0; Lubriol W lubricant additive - 0.1 ÷ 0.5; water - the rest (RU 2327726, 2006).

A disadvantage of the known drilling fluid is its low viscosity, which can lead to various complications when drilling weakly cemented rocks. The known solution also lacks components that allow you to adjust the pH and bind Ca ^{2+ ions} when they come from carbonate rocks, which significantly narrows the scope of this solution.

A group of technical solutions related to a single inventive concept is proposed.

The technical result of the proposed drilling fluid is trouble-free drilling in complicated mining and geological conditions, the ability to control pH and the removal of Ca ^{2+ ions} entering the solution from carbonate rocks.

The technical result according to the first embodiment is achieved by the fact that the proposed drilling fluid contains PBMA bentonite, soda ash, caustic soda, Givpan, Lubriol and water in the following ratio of components, wt.%:

Bentonite PBMA 6.0 ÷ 7.0 soda ash 0.1 ÷ 2.0 caustic soda 0.1 ÷ 0.5 Givpan 0.2 ÷ 0.3 Lubriol 1,0 Water rest

the solution has parameters (table 1).

Table 1 The parameters of the drilling fluid according to option 1 Density, g / cm ³ Conditional viscosity, s Filtration, cm ^3/30 min Plastic viscosity, mPas Dynamic shear stress (CSN), dPa Static shear stress (SNA _1/10 ), dPa 1.08-1.12 60-100 <12 not regulated not regulated not regulated

The technical result according to the second embodiment is achieved by the fact that the proposed drilling fluid contains: PBMA bentonite, soda ash, caustic soda, Givpan, Kamcel PAC-VV and Kamtsel PAC-SV, Lubriol, ALS, antifoam - a ten percent suspension of polyethylene in solar oil or kerosene ( PES) and water, with the following ratio of components, wt.%:

PBMA bentonite 5,0 soda ash 0.1 ÷ 0.5 caustic soda 0.1 ÷ 0.5 Givpan 0.2 ÷ 0.3 Camcel PAC-VV 0.1 ÷ 0.3 Camels PATs-SV 0.1 ÷ 0.3 Lubriol 1,0 ALS 0.2 ÷ 0.3 PES 0.1 ÷ 0.2 water Rest

while the solution has parameters (table 2).

table 2 Drilling fluid options for option 2 Density, g / cm ³ Conditional viscosity, s Filtration, cm ^3/30 min Plastic viscosity, mPas Dynamic shear stress, dPa Static shear stress (CHC _1/10 ), dPa 1.08-1.12 40-50 <12 <15 50-60 20-40 / 50-100

The technical result according to the third embodiment is achieved by the fact that the proposed drilling fluid contains: PBMA bentonite, soda ash, caustic soda, Kamcel PAC-BB and Kamcel PAC-SV, Lubriol, ALS, antifoam - a ten percent suspension of polyethylene in solar oil or kerosene (PES) and water, in the following ratio of components, wt.%:

PBMA bentonite 2.0 caustic soda 0.1 ÷ 0.5 soda ash 0.1 ÷ 0.5 Camcel PAC-VV 0.2 Camels PATs-SV 0.2 ALS 0.2 ÷ 0.3 PES 0.1 Lubriol 1,0 water Rest

the solution has parameters (table 3).

Table 3 The parameters of the drilling fluid according to option 3 Density, g / cm ³ Conditional viscosity, s Filtration, cm ^3/30 min Plastic viscosity, mPas Dynamic shear stress, dPa Static shear stress (СНС1 / 10), dPa 1.06-1.10 30-40 4.0-6.0 fifteen 40-60 20-40 / 50-100

The preparation of the drilling fluid is as follows.

Fresh water is poured into the container for preparing the solution. Poured water is treated with caustic and soda ash at the rate of 1-5 kg / m ³ depending on the pH and the content of Ca ^{2+ ions} . For complete dissolution of bentonite, the ideal pH should be 8.5-9.5, the content of Ca ^{2+ ions} not more than 200 mg / L. The input of both reagents should be carried out through the loading funnel of the ejector mixer in one go.

Next, clay powder is introduced into the water at the rate of 60 kg / m ³ through a hydrojector mixer. The resulting clay suspension is dispersed in a circular pattern for 4 cycles of circulation to obtain a density of 1.045 ÷ 1.05 g / cm ³ , conditional viscosity 25 ÷ 30 s.

To bring the solution parameters to the design, Givpan is entered in one step through the BPR unit.

To prepare the solution according to the second variant, the volume of water is poured into the container minus the volume of water that will be used to dissolve the Kamets PAC BB polymer - 3 kg / m ³ , ALS - 2 kg / m ³ , lubricating additive Lubriol - 10 l / m ³ and antifoam PES-1 - 1 l / m ³ .

Water is treated with caustic and soda ash to reduce the hardness of the water and bentonite is introduced at a rate of 50 kg / m ³ . After complete dissolution of bentonite in the main vessel, an aqueous polymer solution is introduced into it from a small vessel, and it is mixed until homogeneous.

To prepare the solution according to the third option, caustic soda — 0.5 kg / m ³ , calcined soda — 0.5 kg / m ³ , bentonite — 20 kg / m ³ , Kamcel PAC BB — 5 kg / m ³ , ALS, were dissolved in water. - 5 kg / m ³ , Lubriol - 10 l / m ³ , PES-1 - 1 l / m ³ , as described above.

If rocks are represented by loose, weakly cemented unstable sand, gravel, pebbles, sandy loam, loam, sandstones, clays and mudstones, siltstones, Quaternary and Ordovician deposits in the drilling interval, the complications during the passage of these unstable deposits are associated with possible wall screes and landslides. Mud absorption is likely.

To prevent complications, it is recommended to use a fresh clay solution of high viscosity (conditional viscosity can reach up to 100 s), which is achieved by treating the solution with Givpan polymers and highly viscous CMC. High viscosity is needed to improve the cleaning of wells from sand, gravel and to prevent the possible subsidence of sand in containers.

It is proposed to use drilling fluids, the formulations of which are given in tables 4 and 5, as drilling mud during drilling of such rocks.

Table 4 Drilling fluid formulation (option 1) Chemical name Appointment Consumption, kg / m ³ Bentonite PBMA TU 5751-002-58156178-02 colloid formation 60 ÷ 70 soda ash GOST 5100-85 removal of polyvalent ions during solution preparation and drilling 1 ÷ 5 caustic soda GOST 2263-79 pH regulator 1 ÷ 5 Givpan TU 2216-001-04698227-99 thickener and filter reducing agent 2 ÷ 3 Lubriol TU 2458-001-74138808-06 lubricant additive 10 soda ash GOST 5100-85 removal of Ca ^{2+ ions} when drilling a cement beaker fifteen

Table 5 Drilling fluid formulation (option 2) Chemical name Appointment Consumption, kg / m ³ Bentonite PBMA TU 5751-002-58156178-02 formation of colloidal structure of the drilling fluid fifty soda ash GOST 5100-85 removal of polyvalent ions during solution preparation and drilling 1 ÷ 5 caustic soda GOST 2263-79 pH regulator 1 ÷ 5 Givpan TU 2216-001-04698227- 99 thickener and filter reducing agent 2 ÷ 3 Camels PAC-VV TU 2231-010-502-77563-03 thickener and filter reducing agent 1 ÷ 3 Camels PATs-SV TU 2231-010-502-77563-03 1 ÷ 3 Lubriol TU 2458-001-74138808-06 lubricant additive 10 ALS TU 2554-003-04698227-2003 viscosity and filtration reducer 2 ÷ 3 antifoam PES TU 2458-012-20672718-2001 Antifoam agent 1 ÷ 2 soda ash GOST 5100-85 removal of Ca ^{2+ ions} when drilling a cement beaker fifteen

Bentonite clay powder is used to increase the viscosity of the solution and give it thixotropic properties, the formation of a filter cake.

Givpan increases the output of bentonite and reduces water loss.

High viscosity (BB) and medium viscosity (CB) polyanionic cellulose Kamcel PAC-BB and Kamcel PAC-SV reduce water loss and increase the viscosity of solutions.

Since most reagents work effectively in an alkaline environment, caustic soda should be added to the drilling fluid to increase the pH to pH values of 9–10.

If it is necessary to reduce the viscosity of the solution while reducing its water loss, it is recommended that the lignosulfonate reagent ALS be added in an amount of 2–3 kg / m ³ .

During drilling and hoisting operations, highly mineralized formation waters containing polyvalent ions (Ca ²⁺ , Mg ²⁺ , Fe ³⁺ ) may enter the well, which can lead to coagulation of the solution. Ca ^{2+ ions} in large quantities fall into the drilling fluid when drilling cement glasses after cementing casing. To bind polyvalent ions, soda ash is used in concentrations from 1 to 15 kg / m ³ .

To reduce the coefficient of friction during drilling and casing lowering, as well as to reduce the likelihood of differential sticking of the drill string into the drilling fluid, the introduction of a lubricant Lubriol is provided.

These solutions should have the properties shown in table 6.

If rocks in the drilling interval are represented by alternating sandstones, siltstones, and coal seams, these rocks are non-sensible and do not require drilling fluid inhibition.

Basic requirements for drilling mud for drilling such rocks:

- ensuring effective cleaning of the wellbore from sludge;

- prevention of possible absorption of the solution and sticking of the drill string in permeable formations;

- the maximum possible conservation of reservoir properties.

To fulfill these requirements, the application provides solution with a density of 1.06 ÷ 1.10 g / cm ³ and a low value filtering index 4 ÷ 6 cm ^3/30 minutes. The composition of the proposed solution are shown in table 7.

Table 7 The composition of the drilling fluid for drilling the interval under the production string (option 3) Chemical name Appointment Consumption, kg / m ³ Bentonite PBMA TU 5751-002-58156178-02 formation of colloidal structural mud twenty soda ash GOST 5100-85 removal of Ca ^{2+ ions} when drilling a cement beaker 1 ÷ 5 caustic soda GOST 2263-79 pH regulator 1 ÷ 5 Camels PAC-VV TU 2231-010-502-77563-03 thickener and filter reducing agent 2 Camels PATs-SV TU 2231-010-502-77563-03 2 Lubriol TU 2458-001-74138808-06 lubricant additive 10 ALS TU 2554-003-04698227-2003 viscosity and filtration reducer 2 ÷ 3 antifoam PES TU 2458-012-20672718-2001 antifoam one

In this case, the bentonite content is reduced to 20 kg / m ³ and the solution is not treated with Givpan polyacrylate reagent in order to reduce the negative impact on reservoir properties.

A slightly increased consumption of caustic soda in the interval is associated with the need to neutralize humic acids that can be released from coal seams when exposed to mud filtrate.

To reduce the water loss of the solution and give it the required rheological characteristics, the content of high viscosity Kamcel PAC BB cellulose was increased to 3 kg / m ³ and medium viscosity polyanionic cellulose Camcel PAC CB to 3 kg / m ³ .

Camcel PAC BB is designed to control the filtration of the solution while increasing the viscosity. The choice of a highly viscous modification is due to the fact that the carbonaceous sludge, having good adsorption capacity, will carry away polymer molecules from a solution in large quantities. From the experience of previously drilled wells, it is known that, despite the work of all four stages of treatment, it is often necessary to dilute the solution with water and polymer to maintain the required density. At the same time, it is difficult to keep the viscosity value high enough, therefore, in this interval, the highly viscous Kamcel PAC BB especially helps.

In order to reduce excessively high rheological parameters of the solution, the lignosulfonate reagent ALS was included in its composition.

The drilling fluid prepared according to this formulation should have the properties shown in table 8.

Using the proposed drilling fluid allows for trouble-free drilling in complicated geological conditions, provides the ability to control pH and remove Ca ^{2+ ions} entering the solution from carbonate rocks.

Claims (3)

1. A drilling fluid for drilling wells containing bentonite, soda ash, caustic soda, Givpan, a lubricant additive and water, while bentonite PBMA is used as a bentonite, and Lubriol as a lubricant additive in the following ratio of ingredients, wt.%:
PBMA bentonite 6.0-7.0 soda ash 0.1-2.0 caustic soda 0.1-0.5 Givpan 0.2-0.3 Lubriol 1,0 water rest 2. A drilling fluid for drilling wells containing bentonite, soda ash, caustic soda, Givpan, carboxymethyl cellulose, a viscosity reducer and stabilizer, a lubricant additive, antifoam and water, while PBMA bentonite is used as PBMA bentonite, and Kamcel is used as carboxymethyl cellulose and Kamcel PAC-SV, as a viscosity reducer and stabilizer - ALS, and as a defoamer - PES in the following ratio of ingredients, wt.%:
PBMA bentonite 5,0 soda ash 0.1-0.5 caustic soda 0.1-0.5 Givpan 0.2-0.3 Camcel PAC-VV 0.1-0.3 Camels PATs-SV 0.1-0.3 Lubriol 1,0 ALS 0.2-0.3 PES 0.1-0.2 water rest 3. Drilling mud for boreholes containing bentonite, soda ash, caustic soda, carboxymethyl cellulose, a viscosity reducer and stabilizer, a lubricant, antifoam and water, while PBMA bentonite is used as bentonite, and Camels PA is used as carbocarboxymethyl cellulose BB PAC-SV, as a viscosity reducer and stabilizer - ALS, and as an antifoam PES in the following ratio of ingredients, wt.%:
PBMA bentonite 2.0 caustic soda 0.1-0.5 soda ash 0.1-0.5 Camcel PAC-VV 0.2 Camels PATs-SV 0.2 ALS 0.2-0.3 PES 0.1 Lubriol 1,0 water rest