CN1693656A

CN1693656A - Preparation method of low temperature stratum self generating gas deblocking agent and deblocking technology

Info

Publication number: CN1693656A
Application number: CN 200510043632
Authority: CN
Inventors: 臧宝仁; 韩宾
Original assignee: DONGYING HAODE PETROLEUM NEW-TECH DEVELOPMENT Co Ltd
Current assignee: DONGYING HAODE PETROLEUM NEW-TECH DEVELOPMENT Co Ltd
Priority date: 2005-05-30
Filing date: 2005-05-30
Publication date: 2005-11-09

Abstract

This invention discloses a a preparation method of low temperature stratum self generating gas deblock agent. It is made up by A medicament, B medicament and C catalyst. A medicament is made up by hydrochloric acid, glacial acetic acid, phosphoric acid, mutual solvent, and they are mixed in room temperature to uniform solution, the quality content is that hydrochloric acid 15-18%, glacial acetic acid 5-2%, phosphoric acid 5-2%, mutual solvent 3-1% water 72-70%. B is made up by dicyandiamide, ammonium nitrate, urea, and they are agitated for 5 hours in reaction tank at the temperature below 50 degrees centigrade, and then they are crystallized and filtrated, the quality content is that dicyandiamide 35.8-33.8%, ammonium nitrate 34.-32.2%, urea 30-28%. Catalyst C is a molybdenum contain oxide, its addition quality is 0.1-0.3%. A, B and C are mixed as quantity rate 10-8 to 1-2 to 0.1-0.3 when they are used, but B and C are mixed first with four times water.

Description

Preparation method and blockage removal process of low-temperature stratum self-generated gas blockage removal agent

One, the technical field

The invention relates to a preparation method and a blockage removing process of a low-temperature stratum self-generated gas blockage removing agent adopted in development of an oil field for improving crude oil yield.

Second, background Art

Injecting liquid CO at home and abroad₂High temperature autogenous CO in formation₂The recovery ratio is improved by technologies such as mixed gas flooding and foam non-miscible phase flooding, and the obvious effect is obtained in field application. However, CO is injected in liquid state₂In the changeThe steam injection efficiency is seriously influenced by the heat absorption effect which greatly influences the utilization and the exertion of steam injection energy; while the formation is high temperature autogenous CO₂The exhaust assisting technology can carry out reaction only when high temperature is needed, and meanwhile, the influence of endothermic effect also exists. Both the two technologies have the limitation of application and popularization, and the relative mining cost is higher.

Third, the invention

The invention aims to provide a preparation method and a blockage removing process of a low-temperature stratum authigenic gas blockage removing agent, and solves the problems that the prior art has large endothermic effect, influences the utilization of steam injection energy, seriously influences the improvement of steam injection efficiency and influences the yield of crude oil of a driven well.

The technical scheme of the invention is realized by the following modes:

low-temperature stratum self-generated gas blocking remover component combination

Wherein: a medicament (acid)

B medicament (basic organic matter)

C catalyst (molybdenum oxide)

Low carbon organic acid C₁-C₇(stratum self-generated gas energizing heat-removal-assisting blockage-removing new technical inducer)

The medicament A (acidity) is formed by directly mixing hydrochloric acid, glacial acetic acid, phosphoric acid and mutual solvent at room temperature to form a homogeneous solution, and the mass content of each component; 15-18% of hydrochloric acid, 5-2% of glacial acetic acid, 5-2% of phosphoric acid, 3-1% of mutual solvent and 72-70% of clear water.

The B agent (basic organic matter) is prepared with dicyandiamide, ammonium nitrate and urea and through mixing in reactor at 50 deg.c for 5 hr, crystallization and filtering. The mass content of each component is as follows: 35.8 to 33.8 percent of dicyandiamide, 34.2 to 32.2 percent of ammonium nitrate and 30 to 28 percent of urea.

The C reaction catalyst is a molybdenum-containing oxide. It can promote the B medicament to be decomposed at low temperature (30 ℃) to generate water, carbon dioxide gas, ammonia gas and urea. And the urea reacts with the agent A to generate carbon dioxide and ammonium chloride.

Both reactions are exothermic.

When the agent is applied on site, A, B and C are mixed together according to the mass ratio of lO-8: 1-2: O.1-0.3, wherein B and C are mixed with 4 times of clear water, the mixed liquid of the agent A, the agent B and the catalyst C with the clear water is squeezed into the stratum respectively, and the middle part is separated by the clear water. The chemical reacts in the stratum to release heat and gas, so as to energize and unblock the stratum.

Compared with the common acidification technology, the invention has the following advantages:

compared with the prior common acidification technology, the low-temperature self-generated gas energy-increasing and production-recovering technology comprises the following steps: the common acidification technology is only used for blockage removal in a simple sense, and the low-temperature self-generated gas energy-increasing and production-resuming technology can generate a large amount of organic blockage of the pyrolysis oil removal well and can generate a large amount of gas to increase the energy of an oil layer. On the other hand, the method utilizes a low-carbon mixed organic acid deblocking technology to remove various blockages of an oil layer, and finally realizes the effect of obtaining oil yield. The yield increasing mechanism is as follows:

1. reducing crude oil viscosity

When CO is present₂Upon dissolution in crude oil, the viscosity of the crude oil drops significantly, depending on the pressure, temperature and the viscosity of the non-carbonated crude oil. In general, the higher the viscosity of the original crude, the higher the percentage of viscosity reduction by carbonation, and CO₂The viscosity reduction effect of the flooding on medium and heavy oil is more obvious.

2. Improvement of fluidity ratio

Large amount of CO₂Dissolving in crude oil and water will carbonate the crude oil and water, and the viscosity of the crude oil will decrease after carbonation. The relevant tests carried out at 45 ℃ and 12.7MPa showed that CO is present₂Solubility in oilfield injection water5% by mass, and the solubility in crude oil of Liaohe oil field is 15% by mass. The viscosity of the crude oil is reduced, the fluidity of the crude oil is increased, the water-oil fluidity ratio is reduced, and the recovery ratio of the crude oil is improved.

3. Volume expansion of crude oil

A volume of CO₂Dissolved in crude oil, and can increase the volume of the crude oil by 10 to 100 percent according to different pressures, temperatures and crude oil components. The coefficient of expansion being dependent on dissolved CO₂Molar composition and relative molecular mass of the crude oil. CO 2₂Dissolving in crude oil, expanding the volume of crude oil, increasing the kinetic energy in liquid and thus raising oil displacing efficiency.

4. Phase mixing effect

CO₂After mixing with crude oil, not only can the hydrocarbon in the crude oil be extracted and vaporized, but also CO can be formed₂And light hydrocarbons. The oil zone movement is the most effective oil displacement process, and can ensure that the recovery rate reaches more than 90 percent. The Minimum Miscible Pressure (MMP) is CO₂And the minimum pressure at which the crude oil reaches miscible. The minimum miscible pressure depends on CO₂Purity of crude oil, crude oil composition, and reservoir temperature. The minimum miscible pressure increases with increasing reservoir temperature. The minimum miscible pressure is also affected by CO₂Influence of purity (impurity content) if the critical temperature of the impurity is below CO₂The minimum miscible pressure is reduced; on the contrary, ifthe critical temperature of the impurities is higher than CO₂The minimum miscible pressure increases.

5. Reducing interfacial tension

The experimental results show that the residual oil saturation decreases with decreasing oil-water interfacial tension. Majority reservoirThe oil-water interfacial tension of 10-20mN/m, and in order to make the residual oil saturation tend to zero, the oil-water interfacial tension must be reduced to 0.001mN/m or less, and the interfacial tension must be reduced to 0.04mN/m or less, so that the recovery ratio is remarkably improved. CO 2₂The main function of oil displacement is to extract and vaporize light hydrocarbon, a large amount of light hydrocarbon and CO in crude oil₂The oil-water interfacial tension can be greatly reduced by mixing, the residual oil saturation is reduced, and the recovery ratio is improved.

6. Dissolved gas flooding effect

Large amount of CO₂Dissolving in crude oil has effect of dissolving gas drive. The pressure reduction oil extraction mechanism is similar to that of dissolved gas flooding, and as the pressure is reduced, gas escapes from liquid, gas driving force is generated in the liquid, and the oil displacement effect is improved. In addition, some CO₂After the crude oil is displaced, a certain pore space is occupied to become bound gas, and the yield of the crude oil can be increased.

7. Increase permeability

Carbonated crude oil and water not only improve the fluidity ratio of crude oil and water, but also help to inhibit clay swelling. CO 2₂After dissolved in water, the water-soluble polymer shows weak acidity and can react with carbonate of an oil reservoir, so that the permeability of the oil reservoir around an injection well is improved. The visible carbonate reservoir is more favorable for CO₂And (5) oil displacement.

8. Foam oil enhancing action

The mixed gas generated underground forms a bubble film with oil, water and an active agent, and is similar to the microcosmic oil displacement of foam compound flooding.

The resistance of liquid flow is mainly expressed as layer friction (or viscous force), and the flow resistance of the foam composite system is increased by an additional resistance generated by mutual collision of bubbles or liquid drops; meanwhile, the additional resistance generated by the Jamin effect is increased due to the deformation of the bubbles when the bubbles pass through the pore throat. In the process of displacing water-driven residual oil by a foam composite system, foam firstly enters a large pore passage with low resistance, and the pore space originally occupied by water is occupied by foam which is continuously injected. Because the resistance of the bubbles is greater than the resistance of the flow, subsequent fluid (e.g., a blocking agent) can only flow from the channel between the bubbles and the rock into the pore space of the smaller throat unoccupied by the bubbles, bypassing the bubbles, and then foam also enters the pores and throats occupied by the subsequent flow, forcing the subsequent fluid into the smaller throat, which greatly increases the process radius, and allows residual oil remaining in the unconsumed oil layer to be recovered.

The specific technical characteristics of the invention are as follows:

① A new technology for increasing energy and helping discharge of heat from stratum to remove blockage features that under the action of composite catalyst, a great deal of gas is generated by low-temp reaction, and the whole reaction process is exothermic, so it can be widely used in conventional oil well with quickly-decreased energy in oil layer, increasing energy and recovering production, and steam-handling well (before or after steam injection), and can save cost by 25-30%.

② the reaction heat and the gas dissolved in the oil phase reduce the viscosity of the crude oil;

③ generating a large amount of gas under oil layer condition, increasing oil layer energy, inducing fluid inflow in non-active area, improving fluid production effect, and simultaneously generating CO₂The gas also has the effects of viscosity reduction, drainage assistance and oil washing;

④NH₃、NO₂the gas reacts with amino acid and the like in the crude oil to generate a surfactant with good performance, so that the surface of the rock is wetted by water, and the oil flow resistance is reduced;

⑤ acidifying near-wellbore zone rock, removing inorganic blockage, and improving permeability;

⑥ can relieve water sensitivity, acid sensitivity, liquid lock, and water lock, and inhibit clay swelling and migration;

⑦ has strong dispersibility and dissolvability for organic substances such as asphaltene and colloid, and can be used for removing organic substance blockage.

Description of the drawings

FIG. 1-schematic cross-sectional view of an oil reservoir injected according to the invention

In the figure, 1-A medicament injection radius 2-clear partition layer 3-B medicament and mixture of C catalyst and clear water are injected into a well bore with radius 4

The figure is only used for explaining the sequence of injecting the oil layer, does not represent the result after the reaction, and generates new products after the reaction of injecting the catalyst, such as products of carbon dioxide, ammonia gas, urea, ammonium chloride and the like, which respectively play roles of generating pyrolysis oil well blockage, increasing the energy of the oil layer, reducing the viscosity of crude oil, relieving the oil layer blockage and improving the yield of the oil well, and does not have the layering sense in the figure.

Fifth, detailed description of the invention

To further disclose the technical scheme of the invention, the following detailed description is made by the embodiments in combination with the attached drawings of the specification:

the invention relates to a preparation method of a low-temperature stratum self-generated gas blocking remover and a blocking removing process, wherein the blocking remover comprises a compound formula consisting of a medicament A, a medicament B and a catalyst C, the medicament A is injected into an oil layer, the medicament A is separated by clear water in layers, then a mixture of the medicament B, the catalyst C and clear water is injected into the oil layer, the catalyst C catalyzes the chemical reaction of the medicament A and the medicament B in the stratum to generate new substances, and the heat energy generated during the reaction and the generated low carbon mixed with organic acid are utilized to remove various blockages of the oil layer, increase the energy of the oil layer, reduce the viscosity of crude oil and achieve the purpose of increasing the.

The formula of the A medicament comprises hydrochloric acid, glacial acetic acid, phosphoric acid and mutual solvent: mixing and stirring clear water in the mass percentage of 15 percent to 5 percent to 3 percent to 7.3 percent at room temperature to form a homogeneous solution.

The formula of the B medicament is that dicyandiamide, ammonium nitrate and urea are 35.8 percent to 34.2 percent to 30 percent (mass percentage) and are mixed and stirred for 5 hours in a reaction kettle at the temperature lower than 50 ℃, and the mixture is crystallized and filtered to prepare the medicament.

The reaction catalyst is a molybdenum-containing oxide. It can decompose the B medicament at low temperature (30 ℃) to generate water, carbon dioxide gas, ammonia gas and urea. And the urea reacts with the agent A to generate carbon dioxide and ammonium chloride.

Both reactions are exothermic.

When the catalyst is applied on site, the mass percentage of the A agent, the B agent and the C catalyst injected into the stratum is 10: 1: 0.1 (mass ratio)

The method comprises the steps of adding 4 times of clear water into a mixed solution of an agent A, an agent B and a catalyst C, injecting a certain amount of clear water into an oil layer one by one, injecting a mixed solution of an agent B and a catalyst C, adding 4 times of clear water into the mixed solution, injecting a certain amount of clear water into the mixed solution, after the injection, allowing the catalyst to enter the agent B for catalytic reaction, decomposing the agent B into water, carbon dioxide gas, ammonia gas and urea, extruding the urea into the agent A for reaction to generate carbon dioxide and ammonium chloride, discharging heat and gas from the carbon dioxide and the ammonia chloride, increasing energy to the oil layer, reducing the original viscosity, removing various blockages of the oil layer, and increasing the yield of an oil.

Claims

1. A preparation method of a low-temperature stratum autogenous gas blocking remover comprises a medicament A, a medicament B and a catalyst C, and is characterized in that the medicament A is formed by directly mixing hydrochloric acid, glacial acetic acid, phosphoric acid and mutual solvent into a homogeneous solution at room temperature, and the mass content of each component is 15-18% of hydrochloric acid, 5-2% of glacial acetic acid, 5-2% of phosphoric acid, 3-1% of mutual solvent and 72-70% of clear water; the agent B is prepared by mixing and stirring dicyandiamide, ammonium nitrate and urea in a reaction tank for 5 hours at the temperature of lower than 50 ℃, crystallizing and filtering, wherein the mass content of each component is 35.8-33.8% of dicyandiamide, 34.2-32.2% of ammonium nitrate and 30-28% of urea; the catalyst C is a molybdenum-containing oxide, and the addition amount of the catalyst C is 0.1-0.3%; when the catalyst is applied on site, the A medicament, the B medicament and the C catalyst are mixed together according to the mass ratio of A to B to C of 10-8 to 1-2 to 0.1-0.3, wherein the B medicament and the C catalyst are mixed with 4 times of clear water.

2. A process for removing the blockage of low-temp stratum by using the gas-generating blocking remover includes such steps as mixing the medicine B with the catalyst C and 4 times of clean water, injecting the medicine A into oil layer, injecting clean water, injecting the mixture of medicine B and catalyst C, and injecting clean water to squeeze the mixture in well.