Development of wax remover and anti-wax agent for high-wax crude oil and solutions for reducing viscosity in heavy oil.

I. Overview

Experiments were conducted on oil samples from the Xi61 block of the Hailar oilfield, specifically samples from the Bei16-Ho53-47 and Bei16-Ho55-47 oilfields. 100 mL of the field sample was added to an LD-JN pump for bottle testing. A stable emulsion was prepared using a homogenizer at 1500 rpm for at least 1 minute. The stability of the emulsion was observed in a 35℃ constant temperature water bath. 1. Oil samples with a water content greater than 30% but less than 50% were used for testing. 2. The sample was diluted with anhydrous ethanol to a concentration of 1%. 3. The wax-removing and wax-preventing effects under different dosage conditions were tested using a wax-removing and wax-preventing tester. By comparing the wax-removing and wax-preventing effects under different dosage conditions, the optimal site and minimum dosage were identified, and a solution was developed accordingly.

II. Oil Sample Composition Analysis

According to SY/T 5119-2008 Analysis of Soluble Organic Matter and Crude Oil Group Components in Rocks and SY/T 7550-2004 Determination of Wax, Gum, and Asphaltenes Content in Crude Oil, oil samples from two wells in Hailar were analyzed by alumina absorption chromatography. The results are shown in Table 1. Table 1 Oil Composition Analysis Table

Name	Bet3653-47	Bet365-47	Block 61
Waxy, %	16.35	20.62	22.44
gelatinous, %	13.34	12.89	12.31
Asphalt, %	2.16	1.07	1.02
Impurities, %	0.91	0.91	0.89
Moisture content, %	2.13	48.22	2.46
Gas content, %	28.14	—	—
Viscosity, MPAs	185.75	645.17	789.53

Table 1 shows that the main components of the Hailar oil samples, based on data analysis, are saturated hydrocarbons, waxes, gums, and asphaltenes. The Be16Ho53-47 sample has a high asphaltenes content and high gas content, while the Be16Ho55-47 sample has a relatively high wax content, and the oil sample from the Xi61 area has a high viscosity.

III. Indoor Chemical Wax Removal and Anti-wax Performance Test

3.1 Evaluation of the anti-wax properties of LD-JN

Based on the oil quality data of individual oil wells, LD-JN cleaning and prevention system agents were prepared in the laboratory, and the cleaning and prevention effects of the agents were investigated. The data are shown in Table 2. Table 2 Evaluation of the wax prevention performance of LD-JN

Hashtag	Block 16​	Bet365-47	Bet365-47
Temperature ℃	35	35	35
Dosage (ppm)	300	300	300
The decrease in oil adhesion to the wall, %	90.13	90.77	95.57

As shown in Table 2, LD-JN can guarantee the on-site wax prevention and removal needs, as demonstrated by:

1. The amount of oil adhering to the wall decreased by more than 90%, and the effects of penetration, dispersion and anti-waxing of crude oil were very obvious, meeting the standard requirements.
2. The water sound was obvious and rapid when the hand was vibrated, indicating that LD-JN has extremely strong permeability and can dismantle and destroy the waxy skeleton in the oil sample.

According to “SY/T6300-2024 Technical Conditions for Oil Production Cleaners and Wax Inhibitors”, the wax inhibition rates of oil samples from the Xi61 block, Bei16Ho55-47, and Bei16Ho53-47 were tested respectively. The data are shown in Table 3. Table 3 Wax Inhibition Rate of LD-JN

Table 3. Wax Resistance Rate of LD-JN

Serial Number	1	2	3	4	5	6	7	8	9	10
Dosage (ppm)	50	100	150	200	250	300	350	400	450	500
Wax resistance rate % (61%)	5.2	7.1	11.7	21.5	63.5	90.6	92.3	94.5	96.3	98.2
Wax resistance rate (55-47%)	10.3	21.3	44.2	80.1	90.3	91.7	92.3	94.3	95.7	96.4
Wax resistance rate (53-47%)	30.2	50	80	90	92.7	93.8	94.8	95.9	96.8	97.3

The wax resistance curve of LD-JN is shown in Figure 1.
Figure 1: Wax resistance curve of LD-JN

Wax resistance %

Dosing Rate (ppm)
.

shown in Figure 1, the inflection point of the anti-wax rate curve is at a dosage of 300 ppm
. When the dosage is 200 ppm, the anti-wax rate of Bebe 16Ho 53-47 reaches 90%, and Bebe 16Ho 55-47 also meets the standard at 80.1%, but the anti-wax rate of the oil sample from Block X61 is only 21.5%. When the dosage is 250 ppm, the anti-wax rates of Bebe 16Ho 55-47 and Bebe 16Ho 53-47 are both above 90%, but the anti-wax rate of the oil sample from Block X61 is 63.5%. When the dosage reaches 300 ppm, the anti-wax rates of the three oil samples—the oil sample from Block X61, Bebe 16Ho 53-47, and Bebe 16Ho 55-47—all exceed 90%, and further increasing the dosage does not significantly change the anti-wax rate.

3.2 Evaluation of the wax removal performance of LD-JN

According to “SY/T6300-2024 Technical Conditions for Wax Removal and Inhibition Agents in Oil Production”, wax removal rate experiments were conducted using the following formulas in use at Plant 1 (SLJN-YJ), Plant 3 (NMPWR), and Plant 4 (LD-JN). The wax removal rate was calculated by measuring the time required to dissolve 1g of wax balls with 15ml of wax removal agent at 45℃. Due to the low air temperature in the Hailar area, experiments were conducted at a simulated wellhead temperature of 35℃ to investigate the wax dissolution rate at different dosages. The wax removal rates of different agents at different concentrations are shown in Table 4.
Table 4: Wax Removal Rates of Different Agents at Different Dosages

Serial Number		1	2	3	4	5	6	7
Dosage (ml)		15	16	17	18	19	20	twenty one
Wax removal rate (g/min)	SLJN-YJ	0.0080	0.0092	0.0103	0.0104	0.0105	0.0107	0.0107
	NMPWR	0.0073	0.0076	0.0080	0.0084	0.0085	0.0086	0.0086
	LD-JN	0.0160	0.016 2	0.016 3	0.0165	0.016 6	0.016 7	0.016 7

Figure 2. Dewaxing rate of different agents and dosages

Wax removal rate

Dosing Rate (ppm)

of 15 ml (standard dosage), the LD-JN wax removal rate is 0.016 g/min, which meets the standard, while the SLJN-YJ wax removal rate is 0.008 g/min, reaching half of the standard value. With a dosage of 17 ml, the NMPWR wax removal rate is 0.008 g/min, reaching half of the standard value. LD-JN has the best wax removal effect. LD-JN is designed for high wax content and special flooding blocks such as those in the Hailar oilfield, combining both wax removal and wax prevention functions. Field tests have achieved the switching between “removal” and “prevention,” meaning that without shutting down the well, increasing the dosage achieves “wax removal,” and once the load current returns to normal, decreasing the dosage achieves “wax prevention.”

IV. Indoor test of viscosity-reducing properties of pharmaceuticals

The experimental methods were conducted in accordance with the provisions of the Daqing Oilfield Company Limited enterprise standard “Q/SYDQ1235-2015 Product Acceptance and Usage Effect Inspection Indicators and Methods for Paraffin-Based Crude Oil Emulsifying Viscosity Reducers”. When the dosage was 80 ppm, the viscosity reduction rates of the Be-16-Ho 53-47 and Xi-61 block oil samples were 35.5% and 60.3%, respectively, with the Be-16-Ho 55-47 viscosity reduction rate at 92.7%. When the dosage was 400 ppm, the viscosity reduction rate of Be-16-Ho 53-47 was 75.5%, and the viscosity reduction rate of the hope-61 block oil sample was 8%. The viscosity reduction rate of Bebe 16Ho55-47 was 95.9% at 8.3% and 90.3% at 500 ppm. When the dosage reached 500 ppm, the viscosity reduction rate of Bebe 16Ho53-47 was 85.2%, the viscosity reduction rate of the Xi 61 block oil sample was 90.3%, and the viscosity reduction rate of Bebe 16Ho55-47 was 97.3%. When the dosage increased to 500 ppm, the viscosity reduction rates of Bebe 16Ho53-47, the Xi 61 block oil sample, and Bebe 16Ho55-47 were all above 85%. The viscosity reduction rates of different oil samples at different LD-JN concentrations are shown in Table 5.
Table 5: Viscosity Reduction Rates of Different Oil Samples at Different Concentrations

Serial Number		1	2	3	4	5	6	7	8	9
Dosage (ml)		5	10	20	40	80	160	300	400	500
Viscositympas	53-47	176.1	172.6	164.1	145.8	119.8	91.8	70.1	45.5	27.5
	District 61	708.2	621.4	468.9	394.1	314.0	223.4	138.9	92.4	76.6
	55-47	321.3	258.1	129.0	64.5	47.1	40.0	33.6	26.5	17.2
viscosity reduction rate %	53-47	5.2	7.1	11.7	21.5	35.5	50.6	62.3	75.5	85.2
	District 61	10.3	21.3	40.6	50.1	60.3	71.7	82.4	88.3	90.3
	55-47	50.2	60	80	90	92.7	93.8	94.8	95.9	97.3

Figure 3. LD-JN viscosity reduction performance

Curve (viscosityreduction %)

Dosage per ppm

As shown in the graph above, at a dosage of 500 ppm, the viscosity reduction rates of Bebe 16Ho 53-47, hope 61 block oil samples, and Bebe 16Ho 55-47 were all above 85%. With increasing dosage, the three curves showed a tendency to converge. The 55-47 curve exhibited a clear inflection point at 50 ppm, indicating that LD-JN has a rapid onset of action, good efficacy, and significant viscosity-reducing performance advantages.

V. Conclusion

1. At a dosage of 300 ppm, LD-JN achieved a wax prevention rate of over 90% for oil samples from the Xi61 block, Bei16Ho53-47, and Bei16Ho55-47. Under wellhead temperature conditions, the wax removal rate of LD-JN was 0.016 g/min, meeting the standard requirements. LD-JN can meet the actual production needs of Hailar Oilfield in terms of wax prevention and removal.
2. At a dosage of 500 ppm, LD-JN achieved a viscosity reduction rate of over 85% for oil samples from the Xi61 block, as well as for Bei16Ho53-47 and Bei16Ho55-47. The three curves showed a tendency to converge as the dosage increased. LD-JN can ensure normal production operation for specific oil wells in specific blocks.
3. Choose between continuous or intermittent dosing based on the actual site conditions: For wells equipped with dosing devices, choose continuous dosing and adjust the dosing pump flow rate to the optimal dosage; for wells without dosing devices, choose intermittent dosing, dosing approximately every 10 days, with each dosing amount multiplied by a factor of 10. Adjust the dosing amount and frequency based on the pumping unit dynamometer diagram or motor current. When the current rises significantly, check the dynamometer diagram to determine if wax jamming has occurred. If so, promptly apply at least 200 kg of chemical to dislodge the wax jam and reduce the dosing amount after the current returns to normal.
4. LD-JN showed good results on oil samples Bei16Ho53-47 and Bei16Ho55-47 in the Xi61 block, with wax removal rates fully meeting requirements, and wax prevention, viscosity reduction, and reduction in oil adhesion to the wall all exceeding 85%. Given the significant differences between different oil wells, it is advisable to monitor well current changes for prediction. For example, if the original system crude oil viscosity was high, a 200kg per day shock injection can be applied as needed. If wax jamming occurs and the well shuts down, the casing should be filled and soaked for at least 24 hours before restarting. Once the current returns to normal, the dosage should be gradually reduced. LD-JN’s superior wax removal performance allows for adjustments to the dosage to address potential wax jamming issues in oil wells. Designed for high wax content and special block displacement in the Hailar oilfield, LD-JN combines wax removal, wax prevention, and viscosity reduction in one process. Field tests have demonstrated the ability to switch between “wax removal” and “wax prevention,” meaning that “wax removal” can be achieved by increasing the dosage without shutting down the well, and then the dosage can be reduced to “wax prevention” once the load current returns to normal. LD-JN exhibits outstanding performance in wax removal, anti-waxing, and viscosity reduction. It is recommended to conduct field application tests in the Hailar oilfield.

VI. Drug Costs

Based on a production rate of 10 m3 per well:

1. The annual demand for wax prevention is 300ppm × 10m3 × 365 days = 1.1t. Therefore, the annual cost of the agent is 1.1t × 13,900 yuan/t (including tax) = 15,300 yuan.
2. If wax removal is performed twice a year, with 1 ton each time, the annual wax removal requirement is 2 tons. Therefore, the annual cost of the cleaning agent is 2 tons × 13,900 yuan/ton (including tax) = 27,800 yuan.
3. The annual viscosity reduction requirement is 500ppm × 10m3 × 365 days = 1.9t. Therefore, the annual cost of the reagent is 1.9t × 13,900 yuan/t (including tax) = 26,400 yuan.

VII. Economic Performance Evaluation

Before the experiment, the maintenance costs of the oil well measures were as follows: ① Hot cleaning once every two months, with a cost of 3,000 yuan per hot cleaning, totaling 18,000 yuan per year; ② The maximum power consumption of the downhole heating rod was 480 kWh/day, at 0.614 yuan/kWh, with a daily power consumption cost of 294.72 yuan, totaling 106,000 yuan per year; ③ The cost of installing anti-wax clips downhole was 3,000 yuan per time per year, and the cost of pump inspection was 109,700 yuan; ④ The production reduction caused by each well cleaning shutdown was 35,000 yuan per time.

Before the experiment10,000 yuan/year	Hot wash	1.8			Before/After Experiment
	heating rod		10.6
	Repair costs	10.97			4/1
	well stoppage	3.5
total		16.27	10.6	26.87
After the experiment10,000 yuan/year	Wax inhibitor	1.53
	Wax remover	2.78
	Viscosity reducer		2.64
total		4.31	2.64	6.95

Good heavy oil viscosity reducers should meet the following requirements:
(1) flowability and dispersion; (2) static stratification.

Oscillation once              Oscillation Secondary         After resting for 5 minutes