RU2431735C1 - Procedure for restraint of water production in well - Google Patents

Abstract

FIELD: oil and gas production. ^ SUBSTANCE: procedure for restraint of water production in well consists in pumping solution of CL (cultural liquid) into insulated interval. Two equal portions are pumped. The first portion corresponds to solution of CL prepared on soft water of 1000 kg/m3 density at ratio 1:0.5-1, while the second one corresponds to solution prepared on reservoir mineralised water of density up to 1190 kg/m3 at ratio 1:0.3-0.5. ^ EFFECT: raised efficiency of repair-insulation operations due to creation of more resistant to water outbreak screen of water solutions of silicon-organic liquid - CL with controlled period of gelation excluding their preliminary hardening. ^ 3 tbl

Description

The proposal relates to the oil and gas industry, is intended for repair and insulation works in wells, and can be used with coiled tubing.

A known method of limiting water inflow in the well, including the preparation and injection into the well of an aqueous solution of organosilicon liquid [Stroganov V.M., Stroganov A.M. Organosilicon grouting materials AKOR: ways and prospects of development. Interval No. 6, 2006, p.24-30]. The AKOR BN organosilicon liquid and water with a pH <6.5 in a 1: 3 ratio are mixed in the testers of the CA-320 cementing unit, the resulting composition is pumped through the tubing into the well.

The disadvantage of this method is that the composition used in it can be effectively used only for formations with a temperature above 40 ° C. The exposure time of the composition in the formation during gelation at temperatures below 40 ° C is more than 32 hours, which increases the cost of repair and insulation work.

The closest in technical essence to the proposed is a method of limiting water inflow in the well (patent No. 2360099, E21B 33/138, publ. 06/27/2009, Bull. No. 18), which includes the preparation and injection into the well of an aqueous solution of organosilicon liquid (QL). Before or after injection of an aqueous solution of organosilicon liquid, an aqueous solution of sodium silicate is pumped in the following ratio of reactants, volume. %:

aqueous solution of sodium silicate density 1050-1100 kg / m ³ 20-40 aqueous solution of organosilicon liquid 60-80,

moreover, an aqueous solution of organosilicon liquid is obtained by mixing it with produced water with a density of 1000-1180 kg / m in the following ratio, volume. %:

organosilicon liquid 20-70 formation water with a density of 1000-1180 kg / m ³ 30-80,

and injection is carried out through a flexible pipe or through tubing.

The disadvantage of this method is the short gelation time, QOL when in contact with an aqueous solution of sodium silicate instantly forms a gel, which interferes with the deeper penetration of an aqueous solution of QOL into the porous medium of the insulated formation, and, in addition, can lead to an emergency situation - premature setting in the pump-compressor pipes or in a flexible pipe.

The technical task of the proposal is to increase the efficiency of repair and insulation works by creating a longer and more resistant to water breakthrough screen from water-based KZh solutions with an adjustable gelation period, eliminating their premature curing.

The problem is solved by a method of limiting water inflow in a well, including sequential injection of solutions of organosilicon liquid (QL) in water in an isolated interval.

What is new is that the injection is carried out in two equal portions, the first of which is a QOL solution prepared in fresh water with a density of 1000 kg / m ³ in a ratio of 1: 0.5-1, and the second in mineralized formation water with a density of up to 1190 kg / m ³ in a ratio of 1: 0.3-0.5.

In the proposed invention, various organosilicon liquids can be used, for example ethyl silicates, grouting product 119-204, however, it is preferable to use organosilicon grouting materials of the AKOR-BN-group based on a mixture of orthosilicic acid polyesters of various degrees of polymerization (AKOR-BNYuO, AKOR-BN101, AKOR- BN102, AKOR-BNYUZ, AKOR-BN104 and AKOR-BN300), which according to TU 2458-001-01172772-99 are a liquid from tan to dark brown with a freezing temperature below minus 50 ° C and dynamic viscosity of 1-30 MPa · s (at 20 ° C). In the presence of water, AKOR-BN is hydrolyzed to form liquid water-soluble products, which then solidify (gel).

The essence of the invention is as follows. In the well through a tubing or flexible pipe, lowered into the isolation interval, an aqueous QOL solution prepared in the QOL: fresh water ratio with a density of 1000 kg / m ³ equal to 1: 0.5-1 is successively pumped. Next, the same volume of an aqueous solution of QOL prepared on mineralized water with a density of 1100-1190 kg / m ^{3 is} pumped in a ratio of 1: 0.3-0.5. This injection method is explained by the fact that the gelation time of an aqueous solution of QOL prepared in fresh water with a density of 1000 kg / m ³ is longer than a solution prepared in mineralized formation water with a density of 1100-1190 kg / m ³ . The first solution due to this and low viscosity penetrates deeper into the porous medium of the insulated formation, and the second solution is gelled earlier than the first and prevents its extrusion from the formation, forming a gel with a higher density.

When testing the water-insulating properties of organosilicon grouting materials of the AKOR-BN (KZ) group, it was revealed that their results differ slightly, therefore, all tests will be illustrated by the example of the most typical representative of these materials - AKOR-BN 102 reagent.

The nominal viscosity of aqueous solutions of QOL was measured on a VBR-1 instrument, and the gel formation time was studied under laboratory conditions at a temperature of 20 ° C. The results of laboratory studies, presented in table 1, prove that for compositions containing water with a density of 1000 kg / m ³ in the ratio of QOL: water equal to 1: 0.5-1, the gelation time is longer (from 8 h 20 min to 28 h), and the viscosity is lower than that of compositions containing mineralized formation water with a density of 1190 kg / m ³ , which contributes to a deeper penetration of the QOL solution into the pores of the formation. With a ratio of QOL: formation mineralized water with a density of 1100-1190 kg / m ³ equal to 1: 0.2, the gelation time is 1 h 20 min and 1 h, which is not enough for safe injection and can lead to an emergency. The ratio of QOL: formation mineralized water with a density of 1100-1190 kg / m ³ equal to 1: 0.3-0.5 gives the optimal gelation time within 2 hours 30 minutes - 6 hours 10.

Table 1 No. The solution of QOL in fresh water with a density of 1000 kg / m ³ The solution of QOL on the reservoir min. water with a density of 1100 kg / m ³ The solution of QOL on the reservoir min. water with a density of 1190 kg / m ³ Gelation time, hour-min Amount of water per 100 ml AKOR-BN102, ml Conv. solution viscosity, s Amount of water per 100 ml AKOR-BN102, ml Conv. solution viscosity, s Amount of water per 100 ml AKOR-BN102, ml Conv. solution viscosity, s one 150 7.5 38-00 2 150 8.2 31-00 3 150 8.3 26-00 four one hundred 12.7 28-00 5 one hundred 13.1 24-40 6 one hundred 13.5 19-30 7 70 13.1 20-00 8 70 13.9 16-50 9 70 14.7 10-00 10 fifty 14.1 8-20 eleven fifty 14.8 6-10 12 fifty 15.7 4-20 13 thirty 14.7 4-30 fourteen thirty 15.6 3-30 fifteen thirty 16.1 2-30 16 twenty 15,2 2-00 17 twenty 16,0 1-20 eighteen twenty 16.6 1-00

The quality of the resulting gel depends on the concentration of the reagent and the mineralization of the mixing water. It is known that as the water mineralization and the concentration of the QOL solution increase, the density of the gel-like material increases (Pirozhkov V.V., Pysenkov V.G., Lymar I.V., Ageenko E.V., Demyanenko N.A., Stroganov V. M., Stroganov AM Efficiency of new technologies for restricting water inflow tested at the oil fields of RUE “Belorusneft” in 2002-2003 Search and development of oil resources of the Republic of Belarus: Sat scientific works - Issue 5, part 2. - Gomel : BelNIPIneft, 2004 .-- S.73-83). This is also confirmed by the test results that were carried out on reservoir models 120 cm long and 2.7 cm in inner diameter filled with quartz sand. By selecting the fractional composition of quartz sand, models with a permeability of 0.9-1.7 μm ² were obtained. To simulate a flooded oil reservoir, water was pumped through a reservoir model pre-filled with oil. After that, QOL solutions in fresh water with a density of 1000 kg / m ³ in the ratio of QOL: water equal to 1: 0.5-1, and QOL solutions in mineralized water with a density of 1100 and 1190 kg / m ³ in the ratio were pumped into different models of the formation QOL: water, equal to 1: 0.3-0.5, according to the "well-formation" scheme. Next, the models were left to react for 24 hours, after which, by pumping water according to the “reservoir-well” scheme, the breakthrough pressure of the water was determined.

From the averaged results presented in Table 2, it is obvious that the water breakthrough pressure in the models where the QOL solution with mineralized water was injected is greater than in the models with fresh water, an increase in the QOL concentration in the solution also leads to an increase in the water breakthrough pressure in the models.

table 2 No. The composition of the solution (ratio QOL: water) Breakout pressure of the model after reacting for 24 hours, MPa / m The solution of QOL in fresh water with a density of 1000 kg / m ³ The solution of QOL on mineralized formation water with a density of 1100 kg / m ³ The solution of QOL on mineralized formation water with a density of 1190 kg / m ³ one 1: 1 1,5 2 1: 1 2,3 3 1: 1 2,8 four 1: 0.7 2.7 5 1: 0.7 3.6 6 1: 0.7 3.9 7 1: 0.5 3.8 8 1: 0.5 4.3 9 1: 0.5 5.1 10 1: 0.3 4.9 eleven 1: 0.3 5,4 12 1: 0.3 5.7

An increase in the breakthrough pressure as the water mineralization increases to 1190 kg / m ³ and the concentration of QOL in the solution to the QOL: water ratio of 1: 0.3-0.5 confirms the increase in the density of the obtained gel, therefore, the application of the method of sequential injection of QOL solutions on fresh water with a density of 1000 kg / m ³ in a ratio of QOL: water equal to 1: 0.5-1, and on mineralized water with a density of 1100-1190 kg / m ³ in a ratio of QOL: water equal to 1: 0.3- 0.5, contributes to the fact that the first solution due to its low viscosity penetrates deeper into the porous medium from the layer to be coated, and the second solution gels before the first and prevents its extrusion from the formation, forming a gel with a higher density.

To determine the optimal ratio of the portions of QoL solutions prepared with fresh and mineralized water in the reservoir model, two portions of QoL solutions were pumped in different ratios, the test results are presented in Table 3.

Table 3 No. The ratio of portions of aqueous solutions of QOL on fresh water with a density of 1000 kg / m ³ and formation miner, water with a density of 1190 kg / m ^3, respectively Breakout pressure of the model after reacting for 24 hours, MPa / m A solution of QOL in fresh water with a density of 1000 kg / m ³ in a ratio of 1: 1 with a solution of QOL in a reservoir miner. water with a density of 1190 kg / m ³ in a ratio of 1: 0.5 A solution of QOL in fresh water with a density of 1000 kg / m ³ in a ratio of 1: 0.7 with a solution of QOL in a reservoir miner. water with a density of 1190 kg / m ³ in a ratio of 1: 0.5 A solution of QOL in fresh water with a density of 1000 kg / m ³ in a ratio of 1: 0.5 with a solution of QOL in a reservoir miner. water with a density of 1190 kg / m ³ in a ratio of 1: 0.3 one 1: 0.3 1,6 2.9 3,5 2 1: 0.5 2.7 3.3 3.8 3 1: 0.7 3.2 3.9 4.3 four 1: 1 4.0 4.7 5.5 5 1: 1,5 4.0 4.8 5,6

From the results presented in Table 3, it follows that the equal portion ratio is optimal, since at a ratio of 1: 0.5, the model breakthrough pressure after reacting for 24 hours was 2.7, 3.3, and 3.8 MPa / m, with a ratio of 1: 1 it increased and amounted to 4.0, 4.7 and 5.5 MPa / m, with an increase in the ratio to 1: 1.5, the pressure did not change significantly: 4.0, 4.8 and 5.6.

Thus, in this proposal, a result is achieved - increasing the efficiency of repair and insulation works by creating a longer and more resistant to water breakthrough screen from water-based QOL solutions with an adjustable gelation period that excludes their premature curing. The method allows to reduce the volume of produced water in comparison with the prototype by 25-30%, respectively, to reduce material costs for oil production.

Claims (1)

A method of limiting water inflow in a well, comprising sequentially injecting a solution of an organosilicon liquid - QOL in water into an isolated interval, characterized in that the injection is carried out in two equal portions, the first of which is a QL solution prepared in fresh water with a density of 1000 kg / m ³ in a ratio of 1 : 0.5-1, and the second - on mineralized formation water with a density of up to 1190 kg / m ³ in a ratio of 1: 0.3-0.5.