International Journal of Advanced Biotechnology and Research (IJBR) ISSN 0976-2612, Online ISSN 2278–599X, Vol-7, Special Issue-Number4-July, 2016, pp710-716 http://www.bipublication.com Case Report

Study of Improvement Oil-based Drill Cuttings Azadegan Project Oil Field in Iran Using Thermal Desorption Method 1

Tahmasebi Birgani, M.R., 2Nabi Bidhendi, G.R. and 3Rashedi, H. 1

Environmental Planning Alborz Campus Tehran University Department of Environmental Engineering, University of Tehran 3 Biotechnology Group School of chemical Engineering College of Engineering, University of TehranP.o.Box:11155-4563, Tehran, Iran 2

ABSTRACT: This study investigated the effectiveness of treatment is the drill cuttings using thermal desorption. In this method before and after treatment drill cuttings compounds and their properties determined. To study the effect of thermal desorption units and heat for 5 days of the monitored machines. Weight and percentage of each composition and other laboratory tests Retort analysis, Petroleum Hydrocarbon, PH, temperature and Suspended Solid on each of the components is done (oil, water and solid).The results show that heat loss occurs with increasing flow rate of cuttings, logs and constant heat flow rate, respectively, between about 20 to 40 cubic meters / hour, and between 232-274 ° C The amount of petroleum hydrocarbon, PH, temperature and suspended solids from 0.1 to 0.35 mg/l, 6.5-7،30-40 ° C and 15-35 mg per liter will be ordered. The organizers expect the world's values, except for slightly higher than the temperature. The concept of these results is that most of the liquid (oil and water phase) were reserved and reusable. Keywords: oil treatment, drill cuttings, thermal desorption, petroleum hydrocarbon

1. INTRODUCTION Drilling waste and its treatment is an increasingly important part of any oil drilling operation, whether it is on land or off shore. These wastes, which typically include drill fluid cuttings and well bore clean-up fluid are hazardous and must be treated before disposal [1]. Drill cuttings may be contaminated in either water based mud (WBM) or oil based mud (OBM), and while it has become an accepted practice to treat the OBM cuttings, the treatment of WBM cuttings is becoming common in more sensitive environments. Well bore clean-up fluids are typically hydrocarbon contaminated and will also require the filtering of contaminants prior to disposal or reuse. The adverse effects of the discharge from the petroleum (oil) prospecting are

of great concern because of the effect or impact of drill cuttings (oil based, water based, and synthetic based mud) on the immediate environment [2].Crude oil operation requires the use of specific formulated fluid system often referred to as drilling mud. This fluid is used to lubricate the drilling bit and stem, transport formulated cuttings to the surface and seal off porous geologic formulations [3]. The management of drill cuttings involves using thermal desorption method among others. Thermal desorption is the separation and recovery process resulting in three stream; water, oil and solid. The heating volatilizes liquid and the vapor is cooled and separated into water-oil phases [5]; [6]. The liquid phase can be recovered and made into a new

Study of Improvement Oil-based Drill Cuttings Azadegan Project Oil Field in Iran Using Thermal Desorption Method

drilling-fluid system or used as a fuel source, while the solids could be disposed of or reused [7]. It is safe, reliable and economical [8]. A case study of thermal desorption procedure using a TCC-Rotomill cutting plant was undertaken in this study in Azadegan Oil Field In Iran. 2. MATERIALS AND METHOD 2.1. Project Overview Iran is the second-largest producer in the Organization of the Petroleum Exporting Countries (OPEC). With increasing demand for oil from OPEC, Iran is required to raiseits production capacity to maintain its relative share of production within the group in addition to meeting rising domestic energy demand. Iran's long-term goal is to more than double oil capacity to eight million barrels a day (bbld) over the next 20 years, through the addition of one million bbld every five years[12]. To achieve these goals and according toGOI’s second, third, and soon to be approved forth Five Year Development Plan, Iran plans to adopt more functional, sustainable and up-to-date technologies to improve its production capacity by attracting foreign investment and technology [13]. The Azadegan onshore field was the largest oil discovery in Iran in the last30 years and one of the largest undeveloped oil fields in the world in terms of oil-in-place. The Azadegan Field was discovered in 1999 and located in the southwestern province of Khuzestan, a few kilometers east of the border with Iraq (Figure.1 overleaf)[14].

Azadegan oil field, Iran's largest oil field after field, Ghawar (Saudi Arabia) and Bouraghi Square (Kuwait), the world's third largest oil field. Azadegan oil field exploration dates back to 1997 and in the range of 20 to 75 km, 100 km West of Ahwaz and is located in Dasht-e Azadegan[15]. The field's proven capacity was estimated at 33 billion barrels. In 1999, a new oil layer with a capacity of 2. 2 billion barrels, was discovered in this field. North and South Azadegan oil field has two parts. Since 2008, oil production from the southern part with a capacity of 25 thousand barrels of oil per day has begun. North Azadegan is in the vicinity of the Majnoon oil field in Iraq[16]. The field is composed of four distinct reservoir systems, i.e., Sarvak, Kazhdhumi, Gadvanand Fahliyan. The oil in Sarvak reservoir is found to be heavy, while the oil in theremaining three reservoirs is found to be lighter. In terms of oil-inplace, Sarvak is assessed to be most prolific of all accounting for over 90% of the total reserve. Accordingto the Master Development Plan (MDP) for exploration and production, 36 new wells willbe drilled under Stage 1 development and the initial oil production would be 50,000barrels per day (bbld) of oil by the end of the 40th month. Over the next 12 months, the oilproduction would be increased to 150,000 bbld and simultaneously 135 million standardcubic feet per day (Scfd) of gas would be produced for export[17]. Under Stage 2, over thenext 40 months, another 39 wells would be drilled to increase the total oil production to260, 000bbld and gas production to 235 million Scfd[18]. 2.2. Drilling MudsAndDrill Cuttings The actual drilling process starts with laying out all necessary equipment such asgenerator, mud pumps and drawworks including erection of derrick for running and pulling drill strings. A drill bit and drill strings are used to cut soils/rocks to make a hole.As a hole deepens, such hole section needs to be isolated from lower section because ofdifferent formation

Figure.1: Azadegan Project Area

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Study of Improvement Oil-based Drill Cuttings Azadegan Project Oil Field in Iran Using Thermal Desorption Method

pressure or hole problems such as caving, sloughing, etc[19]. The casing isrun and cemented to protect the hole and isolate the hole from the lower section. Theprocess of drilling and setting casing is continued until the final well depth of 1900 – 4300m is reached[20]. During the process of drilling, drilling fluid (also called drilling mud) is circulated in theborehole to balance the reservoir pressure such that the reservoir fluids are not releasedfrom the borehole during drilling; to remove the drilling cutting (rock cuttings) out of theborehole; and to cool the drill bit during drilling[21]. While the top hole is being drilled, waterand periodic spot of bentonite mud is used to clean the hole. For subsequent holesections,drilling mud is used. Drilling mud is pumped into the borehole through the drill string andthen re-circulated to the surface through the annular space between the drill string and thecasing. On the surface, drill cuttings and any gas are separated from the drilling mud thensuch mud is re-circulatedDuring the drilling process, the annular space between the casing and the borehole isfilled, section-by-section, with cementing materials. Cementing of the borehole supportsthe casing and the bore wall, prevents fluid migration between permeable zones andprotect from casing corrosions [22]. Drilling mud is a liquid mixture of special clays, inorganic salts and chemicals, which is Continuously re-circulated in the borehole being drilled. The purpose of the re-circulationis to balance the reservoir pressure, to remove the drill cutting from the borehole and tocool the drill bit[23]. Two types of drilling muds are used in the industry: • Water based muds • Oil based muds Predominantly, water-based drilling muds are in the industry due to their minimal environmental impacts. Natural materials like bentonite and barite are the mainingredients of water based drilling muds[24]. For certain drilling situations

Tahmasebi Birgani, M.R., et al.

such as drilling inreactive shales and high angle directional drilling, oil-based drilling muds are used. Oilbase muds use crude oil, diesel oil, vegetable oil and synthetic oil as the base fluid. The use of water based drilling fluids is planned throughout the Project. This is to reduceboth environmental impact and cost [25],[26]. 2.3. Thermal Desorption Method Thermal desorption is an ex-situ treatment technology that utilizes heat to increase the volatility of contaminants such that they can be removed from a solid matrix: typically, soil, sludge, filter cake, or drill cuttings. desorbers are designed as a separation technology to remove organic compounds from such matrices without thermally destroying them. The volatilized contaminants are then either collected or thermally destroyed in secondary treatment units.A thermal desorption system therefore has two major components; the desorber itself and the off-gas treatment system. Thermal desorption is a thermal soil remediation technique that has been utilized at several hundred environmental remediation projects worldwide. As a mature technology, thermal soil remediation performance can be predicted with a high degree of confidence. 2.4. Sampling AndSample Preparation Samples of drill cuttings were collected from total waste management company. The drill cuttings samples were collected from two different mixing tank using auger and cups. In the pre-treatment stage, the weight and relative percentage of each component of oil, water and solids in the given material was determined. The treatment was done according to the procedure described by TWMMA (Total waste management alliance, 2008). In the process of treatment of drill cuttings, three distinct components were produced. Oil, water and solid (dry power) [9]. Laboratory Analysis The following parameters were used to analyze the requirement for each component. a) Recovered Oil: This was determined using retort analysis.

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Study of Improvement Oil-based Drill Cuttings Azadegan Project Oil Field in Iran Using Thermal Desorption Method

b) Recovered Solid (Dust or Soil): pH and PAHs (Polyaromatic Hydrocarbons) were determined using multi-probe meter. c) Recovered Water: Temperature, pH, suspended solid and PAHs were determined also with a multi-probe meter. 3. RESULTS AND DISCUSSION Results

Test of correlation was applied in calculating the variation of mill temperature with fluid volume.

Table 1 shows the drill cuttings retort (raw material) and its relative percentage Raw Material Wt(g) Oil (%) Water (%) Sample A 1.28 60 20 Sample B 1.36 55 22 Table 1: Drill Cutting Retort (Raw Material) and its Relative Percentage

Solid (%) 20

Total (%) 100

23

100

Tables 2,3 and 4 are mean values for the raw material retort and oil retort for 5 days while table 5 is the variation of mill temperature with flow rate. Day1 Day2 Raw material retort Oil retort Raw material retort Oil(50%) Oil(92%) Oil(30%) Water(25%) Water(0%) Water(24%) Solid(25%) Solid(8%) Solid(46%) S.G(1.32g) S.G(1.40g) Table 2: Mean values for the raw material retort and oil retort for days 1 and 2.

Oil retort Oil(94%) Water(0%) Solid(6%)

Day3 Day4 Raw material retort Oil retort Raw material retort Oil retort Oil(55%) Oil(93%) Oil(25%) Oil(94%) Water(22%) water(0%) Water(20%) Water(0%) Solid(23%) Solid(7%) Solid(55%) Solid(6%) S.G(1.35g) S.G(1.55g) Table 3: Mean values for the raw material retort and oil retort for days 3 and 4. Day5 Raw material retort Oil retort Oil(50%) Oil (90%) Water(7%) Water (0%) Solid(43%) Solid (10%) S.G(1.81g) Table 4:Mean value for the raw material retort and oil retort for day five Rate(m3/hr) Frequency Average temperature© 15 2 281 16 1 285 20 6 274 25 8 264 27 5 267 30 7 252 32 1 246 35 6 243 40 6 232 44 1 220 45 2 222 Table 5: Variation of Mill Temperature with Flow Rate

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Study of Improvement Oil-based Drill Cuttings Azadegan Project Oil Field in Iran Using Thermal Desorption Method

Fig. 2: Variation of Average Mill Temperature with Flow Rate. Tables 6,7, and 8 show the data for recovered oil, solid and water analysis. Recovered oil oil water solid Sample % % % Sample A 93 0 7 Sample B 95 0 5 Table 6: Recovered Oil Result parameter WHO standard Sample A PH 6.5-8.5 6.9 PAHs(mg) 0.5 0.1 Table 7: Recovered Solid Result parameter WHO standard Sample A Temperature© 20-30 33 PH 6.5-8.5 6.7 Suspended solid(mg/l) 50 17 PAHs(mg) 0.5 0.35 Table 8: Recovered Water Result

4. DISCUSSION Drill Cuttings Retort Result Analysis From the analysis of the two samples of drill cuttings used as raw material, the results (table 1) show that the drill cuttings were heavy and good for treatment in the thermal desorption unit plant and the cuttings would regulate the mill temperature, and also conserve the oil and water produced from being destroyed by excessive heat [10]. Variation of Mill Temperature with Flow Rate. The variation of mill temperature with flow rate was monitored for five days, and the findings used for correlation test which resulted as minus one (-1). Thus there is a perfect negative correlation indicating that temperature decreases Tahmasebi Birgani, M.R., et al.

total % 100 100 Sample B 6.7 0.15 Sample B 39 6.8 23 0.25

with increase in the volume of the drill cutting. This was demonstrated in fig.2 which shows negative linear correlation. The clustering of the points around the straight line in fig.2 indicates that there is a strong linear correlation which means that the dependent variable (temperature) decreases as the independent variable (volume) increases which is good for drill cuttings treatment. It was deduced from table 6 that temperature stabilized with the flow rate between the ranges 20-40m3/hr thereby conserving more of the liquid content of drill cuttings [11]. Recovered Oil The result (table 6) shows that there is no water content in the recovered oil. The suspended solid 714

Study of Improvement Oil-based Drill Cuttings Azadegan Project Oil Field in Iran Using Thermal Desorption Method

and hydrocarbon level ere minute and are below discharge limits. The oil recovered by the process is unaffected by the thermal desorption because of relatively low temperature used in the process, and are free from any odour and can be recycled back into the drilling mud system or used as fuel for thermal desorption engine or resold for other purposes. The superior quality of the recovered oil compares favourably to its original state and therefore holds its original economic value [6]. Recovered Solid (Dust) The pH and PAH content determined from the produced solids (dust) (table 7) shows that the values of these parameters were small and below the WHO discharge limit. So the inert solid phase can be used in industry as filler or bulking agent and can be used for concrete work. Recovered Water The result of recovered water analysis (table 8) indicate that the pH, PAHs and suspended solids are minute and below WHO standard. The temperature is slightly above the standard but still appropriate and could be discharged and re-used. 5. CONCLUSION Treatment of drill cuttings is very important because of the potential threat it poses to the environment and human health by extension. This waste contains some hazardous substances which if not properly treated and disposed of will cause serious harm in the environment. There are many methods of treating drill cuttings, but thermal desorption method has shown comparative advantage over others. This is demonstrated in its ability to conserve base liquid contents especially the base oil which has high economic value. This research further shows that the method is most effective, economical and environmentally friendly. The recovery of the products and subsequent recycling and selling help reduce stress on the environment and avoidable economic loss.

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6. REFERENCES 1. TWMA (Total Waste Management Alliance).TCC-Roto Mill. Manual, 2008. 2. R.M. Atlas and R. Bartha R. Fate and Effect of Petroleum in the Marine Environment. Microbiological Review Vol. 49, pp49-80, 1993. 3. T.A. Bauder. “Soil Properties Affecting Wheat Yields Following Drilling Fluid Application.”Journal of Environmental Quality. Vol. 34(5): pp 1687-1696, 2005. 4. G. Kiely. Environmental Engineering.New York, McGraw-Hill, 1998. 5. Mi SWACO. “Calculation of Energy Requirements and Air Emissions for Dry Cuttings Management,” UK, 2005. 6. SDF (Speciality Drilling Fluid). Thermal Desorption System for Treating Drilling Cuttings. Nigeria SDF, 2008. 7. K.M. Bansal and Sugiarto. “Exploration and Production Operations-Waste Management: A Comparative Overview. US and Indonesia Cases”.SPE54345, SPE Asia Pacific Oil and Gas Conference, Jakarta, Indonesias. April 20-22, 1999. 8. R. Snyder (1999). “Drilling More Effective with Fewer Rigs”.World Oil (online). Available: http://www.findarticles.com/cf/p2/articlejhtml 9. TWMA (2009). TCC-Rotomill (online). 10. Available: http//www.twma.comuk/pdf.Tcc Rotomill.pdf. 11. C. Obi. “Drilling Work Findings on Total Waste Alliance”. A Technical Report (unpublished), 2009. 12. F. Caswell. Success in Statistics. London, John Murray Publishers Ltd, 1982. 13. Azadegan Environmental Baseline Studies, Report 1: The Natural Environment, July2003. 14. Azadegan Environmental Baseline Studies, Report 2: The Natural Environment, July2003. 15. Azadegan Environmental Baseline Studies, Report 3: The Pipeline Corridors Survey,July 2003.

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Study of Improvement Oil-based Drill Cuttings Azadegan Project Oil Field in Iran Using Thermal Desorption Method

16. Azadegan Environmental Impact Assessment Scoping Report, January 2004. 17. Azadegan Environmental Baseline Studies, Gaps Closure Report: Cultural Heritageand Archaeology, August 2004. 18. Azadegan Environmental Baseline Studies, Gaps Closure Report: Ecology, August2004. 19. Azadegan Environmental Baseline Studies, Gaps Closure Report: Community Health,August 2004. 20. Azadegan Environmental Baseline Studies, Gaps Closure Report: ydrogeology, 21. August 2004. 22. Azadegan Environmental Baseline Studies, Gaps Closure Report: Social Environment, August 2004. 23. Azadegan Environmental Baseline Studies, Gaps Closure Report: Environmental Pollution, August 2004. 24. Azadegan Environmental Baseline Studies, Gaps Closure Report: Waste Management Practices, August 2004. 25. First Public Consultation Meeting, Ahwaz, June 2004. 26. Community consultation, Project area, September 2004. 27. Second Public Consultation Meeting, Susangerd, September 2004. 28. Azadegan Development Front End Engineering Design (FEED), June 2004.

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