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Petroleum and Natural Gas Industry Standard of the People's Republic of China SY/T5886-93
Sandstone Retarded Acid Performance Evaluation Method
1994-01-06 Issued
China National Petroleum Corporation
1994-06-01 Implementationbzxz.net
Subject Content and Scope of Application
Petroleum and Natural Gas Industry Standard of the People's Republic of China Sandstone Retarded Acid Performance Evaluation Method
This standard specifies the method for determining the retarding and corrosion inhibition performance of retarded acid used for acidizing sandstone reservoirs. This standard is applicable to the research, screening and evaluation of retarded acid used for acidizing sandstone reservoirs. 2
Reference standards
GB6004 Metal wire woven square hole mesh for test sieveSY5336 Recommended practice for conventional core analysis
SY/T5358 Flow test procedure for sensitivity evaluation of sandstone reservoirSY5461 Test method and evaluation index for soil acidification corrosion inhibitor3 Reagents and materials
Hydrochloric acid: chemically pure:
Hydrofluoric acid: chemically pure:
Potassium chloride:
Ammonium chloride;
Kerosene,
Fast acid
Natural core.
Instruments and equipment
Plastic volumetric hopper: 50, 100ml;
Plastic beaker: 100, 250ml
Plastic bottle: 600, 1000ml
Glass sand core bucket: G5:
Test sieve: SsWo.4/o.25
GB 6004--85(40 months):
Constant temperature water bath, room temperature ~95°C, temperature control accuracy ±1°CConstant temperature oil bath: room temperature ~200°C, temperature control accuracy ±1C, constant temperature dry explosion box: room temperature ~3D0°C, temperature control accuracy ±1°C; Timing clock:
Stopwatch: accuracy 0.18
SY/T 5886--93
Analytical balance: sensitivity 0.001g
Bottled fluorine gas into high-pressure electric plunger pump: the working pressure of the pump is 25MPa, and the displacement is 0~80ml/min. Approved by China National Petroleum Corporation on January 6, 1994 and implemented on June 1, 1994
5 Acid preparation
5,1 Soil wall solution
SY/T 588693
According to the test requirements, calculate the amount of hydrochloric acid, fluoric acid and distilled water required for a certain volume of soil acid according to formula (1). When measuring hydrofluoric acid, use a plastic measuring tube or measuring cup. Press distilled water. Add hydrochloric acid and hydrofluoric acid into the plastic bottle in sequence, shake evenly, and determine the actual concentration by acid-base titration. The error should not exceed ±0.2. Finally, add various additives used on site, mix evenly and set aside. V, -Varon-C
In the formula, - the amount of hydrochloric acid or hydrofluoric acid in the earth acid, ml; V—the total amount of earth acid, mls
—-the density of the prepared earth acid, g/cm\; Ci—the concentration of hydrochloric acid or hydrofluoric acid in the earth acid, %β-the density of hydrochloric acid or hydrofluoric acid, g/cm;
C,-the concentration of hydrochloric acid or hydrofluoric acid,%.
Stone, 2 Slow wall solution
Prepare according to the recommended slow acid formula and put it into a plastic bottle for use. 6 Corrosion inhibition performance determination
Perform according to SY5451.
7 Speed performance determination
7.1 Static test method (rock sample weight loss method) 7.1.1 Principle of the method
. (1)
Under normal pressure and temperature not higher than 90°C, compare the weight loss rate of rock samples in slow acid and soil acid to evaluate the static slow performance and ultimate dissolution capacity of slow acid.
7.1.2 Rock sample preparation
7.1.2.1 Select cores (or rock cuttings) suitable for slow acid, or cores (or rock cuttings) from the well to be acidized (or adjacent wells). 7.1.2.2 Clean the bottom of the core according to the provisions of 4.5.1 of SY533B, put it in a drying oven and dry it at 105±1°C until constant weight, and store it in a desiccator.
7,12.3According to the test requirements, take a certain amount of dry explosion core (or rock cuttings), crush it and pass it through the test sieve until the amount of core passing through the sieve is greater than 80% of the amount taken, and mix the rock sample passing through the sieve for later use. 7.1.2.4 According to the carbonate content of the rock sample, treat it with excessive dilute hydrochloric acid, then wash and dry it for later use. 7.1.3 Test procedure
7.1,3,1Weigh the rock sample according to the test requirements, and weigh it to more than 0.001. Calculate the amount of acid used for the test based on 1g of rock sample to 20ml of acid solution, accurately measure it with a plastic measuring stick, and pour it into a plastic beaker. 7.1.3.2
Raise the constant temperature water bath to the test temperature, and place the plastic beaker in the water bath to maintain the constant temperature for 10 to 15 minutes. 7.1.3.3
Put the rock sample into the acid solution and record the time of placement as the reaction start time. Stir rapidly until the rock sample is completely wetted by the acid solution, and then let it stand for 7.1.3.43. The reaction time is $0, 45, 60, 90, 120, 240, …, min, until the final dissolution time of the slow acid is reached. After the reaction reaches the predetermined time, take out the beaker, filter, and rinse with distilled water until the filter is neutral. 7.1.3.6. Put the remaining sample and filter paper into a drying oven at 105 ± 1°C and dry until constant weight. The test record format is shown in Appendix A (refer to 7.1.4). Calculate the weight loss rate according to formula (2). Where: n-—rock sample weight loss rate, % $Y/T 5886-—93
m1-m×100
--Rock sample mass before test, gt
n. —-Rock sample mass after test, g.
7,1,5 Allowable difference
The absolute error of three parallel samples tested under the same conditions shall not exceed 5%, and the arithmetic mean shall be taken as the test result. 7.2 Dynamic test method (core flow test method) (2)
1.2,1 Principle of the method
Under the conditions of simulated formation temperature and pressure, the change rate of permeability of the core before and after passing through the retarding acid and soil acid is compared to evaluate the retarding performance under the dynamic conditions of the retarding acid.
7.2,2 Test apparatus
See Figure 1 for the test apparatus. .
Figure 1 Schematic diagram of core flow test device
1-stable pressure source, 2-ammonium chloride solution tank, 3-acid tank, 4-kerosene tank: 5-spare tank: 6-six-way valve: 7-measuring cylinder 8-water bath (or oil bath): 9-core holder: 10-coil: 11 pressure gauge 7.2.3 Core preparation
7.2.3.1 Select cores suitable for slow acid, or cores to be acidified (or adjacent to acidification), with a permeability of not less than 10×10-8um7.2.3.2 Drill a cylinder with a length of 2.5cm and a diameter of 2.5cm in the same direction as the reservoir fluid, and grind both ends flat and keep them perpendicular to the cylindrical surface.
Test The washing and drying of the core are the same as in 1, 2, and 2. 7.2.3.3
Determine the pore volume of the core. Saturate the core with 2% KC1 solution, and perform other operations according to 5.3.3 and 6.4 of SY/T5358: 7.2.3.4
7.2.4 Preparation of other liquids
7.2.4.1 The brine used in the test is prepared with distilled water according to the mass percentage concentration. 7.2.4.2 The brine and kerosene used in the test are filtered with a glass sand core hopper. The kerosene is treated with silica gel or activated white clay before filtration, and then sealed and stored for 3
.
了.2.5 Test procedure
SY/T 5886—93
7.2.5.1 Select three treated cores with similar physical properties, load them into the core fire holders respectively, and connect the device. 7.2.5.2 Apply annular pressure. Its value is determined according to the size of the test pressure difference to ensure that the fluid does not flow around the core. 7.2.5,3 Turn on the power and raise the constant temperature water bath or oil bath to the test temperature. The test temperature is selected according to the formation conditions. 2.5,4 Under a certain pressure difference, squeeze 3% NH, Cl solution into the core forward until the flow rate is stable. The pressure difference is selected according to the core permeability, and it remains unchanged before and after. Measure the water phase permeability of the three cores before acid treatment respectively. The NH, Cl solution squeezed into K1, K, KB is at least 10 times the total pore volume of the three cores. 7.2.5.5 Squeeze kerosene into the core forward to displace the NH.C1 solution in the core pores until the outflow at the outlet is all kerosene. When the flow rate is stable, measure the oil phase permeability of the three cores before acid treatment: K.1, K.2, K.7.2.5.6 Squeeze acid treatment fluid into the core (reverse squeezing for oil wells and forward squeezing for water wells) to treat the core with acid. The amount of acid squeezed into the core is 6 to 10 times the average pore volume of the three cores. Before squeezing soil acid, the core should be squeezed into dilute hydrochloric acid for pretreatment. Squeeze slow acid according to the slow acid requirement procedure.7.2.5.8.2.5.8.3%NH.CI solution is injected into the core to displace the kerosene in the core pores until the outlet effluent is all kerosene. When the flow rate is stable, measure the oil permeability K:1, K:., K. after acid treatment. 7.2.5.8.3%NH.CI solution is injected into the core to displace the kerosene in the core pores until the outlet effluent is all NH.CI solution. When the flow rate is stable, measure the water permeability K, KaK after acid treatment. See Appendix A (reference) for the test record format. 7.2.6 ... The core permeability is calculated according to Darcy's formula (3): K =
Where: K - the permeability of a certain fluid through the core, um; Q - the constant flow rate of a certain fluid through the core, m1/sμ - the viscosity of the fluid at the test temperature, mPa·S; L - the axial length of the core that a certain fluid passes through, cmAp - the constant pressure difference at both ends when a certain fluid passes through the core, MPa; - the cross-sectional area of the core, cm\.
b. The core permeability change rate is calculated according to formula (4). K'-Ki×100
Where: - the change rate of core permeability, %K; - the oil and water phase permeability after acid treatment, um\K, - the oil and water phase permeability before acid treatment, um. (3)
Tester:
Rock sample type
Test temperature
Holder No. 1
Core No.
Pore volume, m1
Gas permeability, umz
Length, cm
Cross-sectional area, c㎡
Specified item
tTester:
K'. 1
SY/T 6886-93
Attachment A
Retarded acid performance detailed price test record format
(reference)
Rock sample weight loss test record sheet
. Well number
Test time
Auditor,
Auditor,
, layer,
Acid volume
Test date:
Rock sample mass before acidizingRock sample mass after acidizing
Core flow test record sheet
Outflow
Test date:
Test temperature
Acid flow
: Layer
: Depth
Permeability
Weight loss rate
Average permeability
Additional remarks,
sY/t 5886—93
This standard is proposed and managed by the Oilfield Chemistry Professional Standardization Technical Committee. This standard was drafted by the Oil Production Technology Research Institute of Shengli Petroleum Administration Bureau. The main drafters of this standard are Zhang Huaixiang and Sun Huiyi.
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