Experience of microbial enhanced oil recovery ...

Petroleum Science and Technology

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Experience of microbial enhanced oil recovery methods at Azerbaijan fields Khidir M. Ibrahimov, Nahide I. Guseynova & Farida Y. Abdullayeva To cite this article: Khidir M. Ibrahimov, Nahide I. Guseynova & Farida Y. Abdullayeva (2017) Experience of microbial enhanced oil recovery methods at Azerbaijan fields, Petroleum Science and Technology, 35:18, 1822-1830, DOI: 10.1080/10916466.2017.1360910 To link to this article: https://doi.org/10.1080/10916466.2017.1360910

Published online: 16 Nov 2017.

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Date: 29 November 2017, At: 21:16

PETROLEUM SCIENCE AND TECHNOLOGY , VOL. , NO. , – https://doi.org/./..

Experience of microbial enhanced oil recovery methods at Azerbaijan fields Khidir M. Ibrahimov, Nahide I. Guseynova, and Farida Y. Abdullayeva

Downloaded by [85.132.44.125] at 21:16 29 November 2017

“Oil Gas Scientific Research Project” Institute, SOCAR, Baku, Azerbaijan

ABSTRACT

KEYWORDS

The paper describes the application of microbial enhanced oil recovery methods on the fields at a later stage of development. Experimental data of long-term analyses of creation and successful use of biotechnologies and their application on the fields located in Azerbaijan are discussed. Data analysis evaluates the information concerning the efficiency of the process. The analytical methods could be useful in predicting the effect of enhanced oil recovery methods on any other field.

microbial enhanced oil recovery methods; microbial methods of impact on a reservoir; analysis of the hydrodynamic state of a reservoir; well interference; flow and potential functions

1. Introduction Biotechnology is used to solve environmental, raw material, food and energy issues, and is widely used in the oil industry as well. Success of biotechnological stimulation methods is associated with the achievements of the petroleum microbiology. Studies of geochemical activity of microorganisms allow us to formulate and prove the stimulation concept, which is based on the utilization of the ability of microorganisms to generate biogas, surface-active compounds, organic acids, and polymers. Microbial activity under reservoir conditions has a significant effect on the physical and chemical properties of reservoir fluids and on the mechanism of the formation micro-processes, which as a result affects oil recovery. Remarkable results have been obtained in depleted fields where application of conventional, physical, and chemical displacement methods is inefficient and unprofitable. Application of biotechnology gives positive results in many advanced oil countries of the world. Due to the fact that onshore fields are in the late stage of development, marked by large residual oil reserves and degradation of their structure and quality, biotechnology is widely used in Azerbaijan. At the beginning, we provide brief information about microbial enhanced oil recovery (MEOR) methods.

2. Theory and definitions Theoretical biotechnological foundations for enhanced oil recovery are based on the following assumptions: – Various groups of microorganisms are widely distributed in the oil fields. Coming into the oil stratum while drilling and injecting, these microorganisms do not lose their vital activity during biochemical life. – Various microorganisms are capable of converting a complex of petroleum and other organic compounds into simpler forms. The products of the life-support of microorganisms are agents such CONTACT Nahide I. Guseynova [email protected] “Oil Gas Scientific Research Project” Institute, SOCAR, H. Zardabi av. a, Baku Az, Azerbaijan. Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/LPET. ©  Taylor & Francis Group, LLC


PETROLEUM SCIENCE AND TECHNOLOGY

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as CO2 , CH4 , H2 , biological surface-active substances (bio-SAS) and thickening agents, solvents, alcohols, acids, and others active compounds. These substances are recognized in the practice of oil production and oil displacement. – Microorganisms are capable of producing oil-sweep bio-SAS directly in the stratum. MEOR methods are divided into two groups. (1) The first group includes methods where it is possible to adjust the parameters of injection into the formation using the compound obtained by the microorganisms on the surface of the ground in special installations. These can be biopolymers, bio-SAS, solvents, emulsifiers, and other compounds. These methods are based on the improvement of water properties for oil-sweep and actually interlock with the chemicals. (2) Another group of techniques includes the formation of oil-displacing agents by microorganisms directly into the layer. There are two ways of influencing the reservoir: (a) the introduction into the formation of microorganisms and nutrients for them; and (b) the introduction into the formation of activating nutrient reservoir microflora.

3. Equipment and processes used Most of the biotechnological modifications are based on the cultivation of microorganisms directly into the reservoir with the introduction of nutrient substrates from the ground. Selection of substrates and nutrient medium with microorganisms is the main factor, ensuring the success of bioprocesses. Technology has spread widely so-called “molasses fermentation,” based on the introduction of the reservoir as a breeding ground of molasses – waste generated in the production of sugar from sugar cane or sugar beet. This technology is used in many countries around the world – the United States, Poland, Romania, Hungary, and Russia. The use of molasses (M) due to its availability and composition provides intensive gassing due to the activity of gas-forming microorganisms. This product is produced in Azerbaijan factory for the production of sugar from sugar beet in the Imishli town. Another substrate, milk whey (MW), is a byproduct of the processing of milk into cheese. Its advantage over the molasses composition is determined by richer mineral and organic compounds, as well as by a wide range of microorganisms. The molasses is used only as a power supply for the microorganisms, whereas the serum MW is used both as the source of microorganisms and as a power supply for them. This greatly simplifies the process and makes it more economical. It has rheological properties such as high viscosity and density. Due to the lower surface tension at the oil–water phase, the oil displacement coefficient increases by 15–18% compared to the water. Considering its availability and features, whey is positioned at the first place in the biotechnology oil production, in oil-producing regions such as Azerbaijan, from technological, economic and ecological points of view. Activated sludge (AS) produced during the treatment of domestic and industrial wastewater in Baku on Govsany aerator station (Azerbaijan) is used as a source of microorganisms. It is a particulate organic material saturated with different groups of microorganisms. Furthermore, the AS can be obtained directly from the source reservoir oil-displacing agents such as carbon dioxide and methane during the fermentation. In Azerbaijan, there is a quite reliable source of raw materials and the production is well established, which allows meeting the needs of the oil industry’s needs in the AS. The pilot projects on microbial stimulation were started in 1986 for the first time in Azerbaijan on an area of the field Magomedli Fatmai (oil-and-gas production department “Binagadyneft”). To date bioinfluence is already implemented at 19 sites in 15 fields of the Absheron Peninsula, including Sian-Shore, Sulu-Tepe, Balakhani-Sabunchu-Ramana, Kala, Ateshgah, Kushhana, and others. By using this method, about 170 t of oil is additionally produced (Mekhtiyev and Rzayeva 2008). Specific economic effect on all objects is 6.7 t/t, i.e., per 1 t additionally injected bioreagents received 6.7 t (Table 1). The objects are described as the difference between the geological and physical conditions, and physical and chemical properties of reservoir fluids as well. Range indicators are wide enough, especially on parameters such as permeability of the reservoir (0.044–0.492 mm2 ), density (828–940 g/m3 ) and the viscosity

, , , ,. ,.



. ,.

    



 

“Binagadineft” “Balakhanineft” “Surakhanineft” “Bibieybatneft” Named after A.D. Amirov Named after G.Z. Tagiyev “Absheronneft” Total

Milk whey (MW)

Number of stimulation objects

Oil gas production department

 ,



,  — , ,

Activated sludge (AS)

 .

—

— — — . 

Molasses

— 



— — — — —

Hydrocarbon-alkaline solution

The amount of injected culture liquid, t

Table . Economic performance of MEOR metods implemented by “Azneft” PU (SOCAR) (as of January , ).

 



    

Amount of production wells under stimulation


,. ,.

,

, , , ,. ,

Total oil production due to technology, t

. .

.

. . . . .

Specific technological effect, t/t

1824 KH. M. IBRAHIMOV ET AL.


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(2.0–13.0 mPa·s) of reservoir oil, and formation water salinity (16.0–141.0 g/L). The temperature of the reservoir varies from 20°C to 36°C. The success of the event depends largely on the correct object picked under the influence of the relevant technology and vice versa. Therefore, biotechnology should be carried out in strict accordance with the criteria of their implementation, which include geological and physical, technological and logistical requirements for the selected object (for example, the properties of oil and water, the data collector, the size of the injected slug placement of wells, provision of equipment, essential nutrients substrates and microorganisms, etc.) (Ismayilov et al. 2014).


4. Results and discussions The analytical findings obtained from two onshore fields of the Absheron Peninsula, namely “Bibiheybat” and “Pirallahi,” are described below. The biotechnological impact was carried out at three sites on “Bibiheybat” field, and various modifications of biotechnology were used at different times. Two of the objects correspond to V horizon, and the third X to productive stratum horizon. At the 1st object, starting from 1998, it was pumping of the composition consisting of MW and AS, at the 2nd object, in 2003, only MW was pumped into the reservoir, and at the 3rd object, since 2006, the composition of AS and M was used. This paper presents the results of the longest technologically efficient process, which is carried out on the 1st object placed in the northwestern part, i.e., V horizon. At the beginning of the process, the oil-bearing zone of the facility amounted to 60 ha with a depth of 550 m and net pay thickness of 37 m. There are 18 production wells around the injection well with an average daily production of 0.6 t and 7.0 t of water. The total water production reached 91%, and the formation temperature was 35°C. The current state of the horizon is characterized by low formation pressure (1.2 MPa) and low permeability (0.159 mm2 ), which led to the decrease in production wells operating in the area. Under these conditions in 1998–2007, it held eight bioinfluence cycles during which the layers pumped 288 t and 1220 t of MS and AS, respectively. Figure 1 shows the dynamics of the injection volumes bioreagents. The response of wells on bioinfluence was different. Some wells, located near the injector, such as wells Nos. 2419 and 2137 (the distance to the injection well was 200 m and 107.5 m, respectively), responded by raising production rates in 2–2.5 months after the start of injection and before the completion of the 1st cycle of exposure. The increased production rates were 1.36 and 1.92 times, respectively. Others, including well No. 2416 located 225 m from the injection well, have significantly higher impact on production rates than the initial (1.54 times) after all cycles. Reinjection led to responses and outermost wells (Nos. 2188 and 2821), while the excess flow rates were the highest being 200%. Of the 17 production wells, 11 wells were reacting with increasing flow rates, i.e., 65%, which

Figure . Dynamics of bioreagents injection into V horizon reservoirs of the Bibiheybat field.

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KH. M. IBRAHIMOV ET AL.


Figure . The dynamics of oil production rates from V horizon of the Bibiheybat field.

can be considered a successful outcome. Across the group, the mean flow rate of wells has increased 1.18 times, and the increase in production through biotechnology has averaged 43.6%. In some wells, a decrease in the initial rate is observed after the injection cycles (well Nos. 2141 and 3920), which can be explained by a decrease in the effect of the process or its extinction as a result of failure or delay of the next injection cycle bioreagents. Dynamics of oil flow on the plot (Figure 2) showed that the period of increase of this index coincides with periods of stimulation and depends on the composition. For example, in 1998, after the injection of the composition consisting of 69 t MS and 158 t AI, average daily production rate for the year increased from 0.58 to 1.09 t. Positive dynamics was maintained until the end of 2002, when 120 t MW downloads and 50 t AS were produced. Since 2003, MW has only been pumped in less than the required amount, which has a negative impact on the dynamics of the process. The average production rate at the area dropped from maximum 1.39 t in 2004 to 1.06 t in 2005 and then to 0.8 tonnes in 2006. Despite this, for the whole period 1998 to 2009 from this area, bioinfluence through the use of biotechnology managed to produce about 24 thousand tonnes of oil. Figure 3 shows the distribution of oil growth by years of exposure. It should be noted that this increase was distributed to the entire bioinfluence period unevenly. At the beginning of the process in 1998, when the amount pumped 227 t composition, growth of oil from the site was 2,693 t, accounting for 11% of the received for the entire period of exposure. In 1999– 2002, due to incomplete volume injection of bioreagents, gains decreased by half. It reached 100–170 t, amounting 7–10% of the total. In 2003, when the layers were pumped twice the initial value of MW (416 t), the growth of production wells increased significantly, which provided an increase of 4,614 t, accounting for 19% of the total increase. Despite the fact that in 2004 the number of the next injected into the reservoir bioreagents again almost halved (240 t MW), the development of bioprocesses in the

Figure . Distribution of incremental oil production by years.



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formation continued in an increasing rate and the amount of additional oil produced in the area has reached a significant value 3,809 t, which amounted to 19% the total increase. A significant decrease in the volume injected (100 t MW) in the following year resulted in the extinction process. The gain was reduced to 2,370 t, accounting for 10% of the total increase. In 2007–2009, the production decline continued that affected the growth, which at the end of the process was only 1%. Subsequently, it was decided to suspend the AS downloads with MW and expediency of transition to a new biotechnological modification. Evaluation of the results of applying the method in “Bibiheybat” field led to the conclusion that the effectiveness of the event as a whole depended on the timely maintenance of intrastratal process by generating an oil-displacing agent, which provided additional oil. The “Pirallahi” field application of microbiological methods stimulation started in 2009. Development and exploitation of deposits in “Pirallahi” started at the beginning of the last century. The lower parts of productive strata namely Kirmaki (K) and Pre-Kirmaki over are oil bearing. The selected area for the pilot for the impact on the “Pirallahi” field has an area of 25 ha. In the selected area, out of 32 wells, one is the injection well. Production wells developed upper sections of Kirmaki Formation (KS). Prior to the application of microbiological effects, the oil production in the 3rd quarter of 2009 decreased by 30% compared to the rest. The recovery rate of the selected area to the current time is 0.39. A preliminary analysis of field data showed that reservoir conditions at the site meet the criteria of applicability of microbiological effects. Therefore, the need for techniques to improve oil recovery through the use of microbiological impact on the producing formation is required. Download of the bioreagents was launched in August 2009, and continued for about 2 months. MW was used as a bioreagent. After a period of time, the microorganisms adapt to the environment (this period is different for each field), as expected, the first signs of reaction wells to bioinfluence, and it was

Figure . Map of the distribution functions of potential and current module of filtration rate in the experimental part of the deposit at the Pirallahi field (SWR horizon): (a) lines of current; (b) equipotential lines; (c) module of filtration rate.


1828


Figure . Map of the distribution function of complex building lines on the experimental plot at the Pirallahi field (KS horizon): (a) in the Cartesian coordinate system; (b) in the polar coordinate system.

mixed. In accordance with a change in flow rate, all production wells were divided into several groups. In the first group of wells, the production rate increased (e.g., Nos. 436, 437, and 498), in the second group, the production rate stabilized (e.g., Nos. 905, 908, and 910), and in the third group, the smallest one, debit wells continued to fall (e.g., Nos. 96, 937, and 938). In addition, there were wells whose production rate either increased or decreased, i.e., as it was throbbed. It would seem that the smaller the distance between the production and injection wells, the greater the likelihood of increasing their production rate. However, the actual changes in flow rates did not confirm this assumption. For this reason, an analysis of geological and hydrodynamic condition of the formation and perforation zone wells is carried out at the test site. Calculation and graphical visualization of the main characteristics of the distribution of the seepage state formation in the exposure area allowed holding both qualitative and quantitative assessments of the impact of the prospects. On the basis of data on the average monthly production rate of oil and water wells, on the date preceding the start of the stimulation (July 2009) in the target area, the distribution of values of functions of the current building, the filtration rate, gradients was analyzed (Gasymly, Guseynova, and Abdullayeva 2010). These maps are shown in Figures 4–6. The analysis showed that the area of the test site is not uniform in distribution filtration characteristics. It was concluded that the productivity of production wells in the area does not depend on the proximity of the injection well, and the activity of the filtration zone in which they are operated. The same reason was explained by the process of active transport of solids in the bottom of the well, the formation of sand plugs, and perforating the damage zone in one of the wells. It was found that for highly productive work,



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Figure . Map of the distribution of the gradients of potential and current function on the experimental plot at the Pirallahi field (SWR horizon): (a) gradient vector potential function; (b) gradient vector flow function.

there must be a favorable combination of hydrodynamic factors that characterize the zone of influence of the production well. Among these factors are the availability of sufficient capacity at the advancing front of the reservoir fluid and efficient filtration rate from the injection zone of influence in the wells. Calculating the data before the impact on the layers, one can predict the impact of the ongoing process on the productivity of each well exploited in the area of implementation. Looking ahead, we note that to confirm the predicted results after the pilot area, microbiological impact work has been done over the results of the forecast and actual data. To each well in the area, the graphs of productivity for the 6 months of operation were constructed, three of which were in the period prior to the impact and three in the period after exposure. Here are some examples. According to the forecast from the well No. 944, located in the immediate vicinity of the injection well No. 913, the high oil flow rates were not expected. The real work of this well in time showed that in the period preceding injection of bioreagents, its flow rate was 0.4–0.6 t/day and remained stable in the whole period of adaptation (June–October 2009). Later, the production rate increased up to 1.0 t/day (in January 2010), although this rise was short-lived. Since March, output declined to 0.3 t/day and continued to remain at the same low level (Figure 7). Thus, the prediction was confirmed.

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Figure . The distribution of oil flow borehole Nos.  and  in time for the experimental part of the deposit at the Pirallahi field.

According to the forecast, well No. 931, located at a considerable distance from the injection, is expected to increase oil production. An analysis of the graph showing the changes in the productivity of the well showed that the stimulation to the period from May to July 2009 production rate of the well decreased from 1.7 t/day to 0.7 t/day. Further, during the injection of bioreagents, this figure began to increase in February 2010 and reached 1.8 t/day, i.e., the flow rate of the well was restored within 4 months after the injection (Figure 7). Preliminary forecast was justified. This method compared data for all wells in the pilot area and obtained satisfactory results. The generalization of the experience gained in conducting microbiological impact on the Pirallahi field allowed for a general procedure for predicting the effectiveness of the stimulation with the filtration reservoir parameters. This procedure used the methods of diagnosis and the hydrodynamic classification rank. Application of the developed method allows us to carry out a preliminary grouping of wells on the effectiveness of the impact of the formation. From wells exposed to bioinfluence, five wells (Nos. 96, 937, 938, 942, and 944) showed a negative result and the flow rates decreased. Ten wells (Nos. 905, 908, 910, 915, 917, 934, 936, 946, 948, and 960), the production rates remained unchanged. For sixteen wells (Nos. 178, 436, 437, 465, 498, 907, 911, 912, 931, 935, 939, 941, 945, 958, 964, and 991) the production rates have been increased production rates. Of the 31 wells, only one consideration (No. 178) was classified incorrectly. Given the success of the forecast, the proposed method has been recommended for the preliminary assessment of the effectiveness of bioinfluence in the oil fields.

5. Conclusions 1. On the basis of long experience, comprehensive data have been obtained on the establishment and successful use of biotechnologies and their modifications in the fields of the country. 2. Sustainable sources of raw material have been revealed in the territory of Azerbaijan, which allows us to satisfy the demands of the oil industry through microbiological methods of stimulation aimed at increased oil recovery. 3. With an aim to ensure implementation of microbial exposure in the oil fields, the process requirements have been developed along with the methods of a preliminary assessment of the MEOR effectiveness.

References Gasymly, A. M., N. I. Guseynova, and F. Y. Abdullayeva. 2010. Development of preliminary estimate methods of microbiological influence efficiency on a layer on the basis of producing ability variation analysis of well on the experimental ground of the Pirallahi oil field. SOCAR Proceedings 4(4):22–52. Ismayilov, F. S., A. M. Gasymly, F. Y. Abdullayeva, et al. 2014. Some results of microbiological method adaptation on onshore fields in Azerbaijan. Azerbaijan Oil Industry 7 (8):28–31. Mekhtiyev, U. Sh., and F. M. Rzayeva. 2008. Employment experience of microbiological methods of increasing of layers oil recovery on the fields of Azerbaijan. Baku, Azerbaijan: Scientific Research Institute of SOCAR.