Mining-Assisted Heavy Oil Production (MAHOP)

This research aims to investigate and compare the ultimate recovery from the largest oil reserve in Turkey (1.85 billion barrels) using a new method called mining-assisted heavy oil production (MAHOP) with conventional SAGD. Tunnels will be excavated from the surface to the reservoir. Fan-shaped up holes will then be drilled in the reservoir from the tunnels.Heavy oil production through these tunnels will be explored using SAGD method. Several numerical models have been designed using CMG’s STARS simulator. Since the fan wells are opened vertically and at certain intervals along the tunnel, both a tight vertical fracturing of these wells and a separate fracture network formed by micro fractures in the vicinity of the fan holes are formed.The validation of these hypotheses has been conducted in CMG which showed that MAHOP gave better results compared to conventional SAGD where two horizontal wells are used. MAHOP gave better recovery values with less steam oil ratios. With the results of the simulation study a laboratory model was designed. Experimental operational parameters using three different wettability cases were simulated to observe recovery by considering several possible physical effects such as steam distillation and in-situ upgrading. Saturation and pressure distributions were also obtained

Çatlak etkisinin sınırlandırılarak, rezervde kalan petrol doymuşluğunun, bilgisayarlı tomografi ile gözlenmesi.

Recovery estimations of fractured reservoirs are considered to be extremely challenging due to complexity and heterogeneity of the geological patterns. Most reservoirs consist of natural and artificial fractures, including isolated microscopic fissures. These fractures form complicated paths for reservoir characterization and fluid movement that ultimately impacts production performance and ultimate recovery. In naturally fractured reservoirs, the matrix is the dominant storage area, while the main flowing channels are fractures. Oil production from fractured reservoirs results in varying saturation values throughout the reservoir. This is due to the microscopic fissures and heterogeneity of the fracture environment, which could not be swept thoroughly. Higher production / injection ratios also enhance the fingering effect by passing oil through the reservoir. To get rid off fingering or minimize, a polymer gel application is applied to the fractured cores to reduce residual oil saturation and to increase oil production. In this study, naturally and artificially fractured cores were used. Analytical and experimental calculations were performed in order to understand the physical vi structure of the cores. After the characteriztion of the fractured cores a polymer gel application is done to limit the fracture effect and increase oil recovery. Equivalent fracture aperture measurements were done by microscope and compared with the analytical calculations with cubic law. Using CT scanner images, matrix porosity and saturation calculations were done. Matrix permeability and fracture permeability values were found before and after the polymer gel injection application. Measurements of the fractures were completed by using microscope to verify the analytical calculations. Laboratory results were defined by the equation developed for predicting equivalent fracture apertures with and without polymer gel as Improved Cubic Law (ICL). Shrinkage in equivalent fracture aperture was also defined by ICL observed by microscope. Using ICL, analytical calculations were done in different environments. Equivalent fracture apertures were calculated for all the experimental flow rates under laminar flow. ICL has worked with the fractured cores flow definition whereas not for homogeneous cores. There is a direct relation between fracture permeability with equivalent fracture aperture. The experiments with different environments (initially oil saturated and water saturated) in the cores, with calculations of equivalent fracture aperture and fracture permeability, showed similar results. The effect of polymer gel conformance to increase recovery by decreasing equivalent fracture aperture plugging was proven. Moreover, the decrese in equivalent fracture aperture in the cores were resulted in decreasing fracture permeability respectively.Ph.D. - Doctoral Progra

Application of VAPEX to carbonate and sandstone reservoirs

TÜBİTAK MİSAG NSF-17.05.2003Bu çalışmanın amacı VAPEX yönteminin ağır petrol içeren karbonat ve kumlası içeren rezcrvuarlara uygulanabilirliğini araştırmaktır. Bu amaca ulaşmak için denyler yapılmış ve sayısal benzetim teknikleri kullanılmıştır. Değişik yatay kuyu sistemleri, değişik gazlar ve değişik debiler kullanılarak saha ve pilot uygulamalar için bir veritabam oluşturulmuştur. Deneysel sonuçlar VAPEX işleminin homojen kumtaşlarmda heterojen karbonatlara oranla daha iyi kurlarını verdiğini ve N-bütan enjeksiyonunun propan ve karbon dioksite oranla daha iyi sonuçlar verdiğini göstermiştir. Deneyler asfalt çökeliminin kullanıldığı bir sayısal benzetim programı ile modellendi. Asfalt çökeliminin çözücü odası gelişimi ile doğru orantılı olduğu görüldü

Exploitation of Bati Raman field using advanced thermal methods: MAHOP VS. CSHP

© 2021 Elsevier B.V.The aim of this work is to examine and estimate the ultimate recovery from Turkey's largest oil reserve (1.85 billion barrels) utilizing a new approach called mining-assisted heavy oil production (MAHOP) and conventional steam injection horizontal production (CSHP) method. In MAHOP, declines (tunnels) are excavated from the surface to the reservoir and proceed along the reservoir's bottom. Fan-shaped steam injection holes are drilled from the upper and lower sides of the reservoir with conventional steam-assisted gravity drainage (SAGD). The suggested CSHP method uses conventional vertical wells as steam injectors and produces heated oil from newly drilled horizontal well pairs. To reach this goal, an experimental scaled model and a numerical model have been designed and developed. Laboratory studies have been carried on three different wettability environments to observe the effect of wettability on the ultimate recovery. The oil recovery obtained from MAHOP at different wettability environments varied with higher steam injection temperatures. The highest recovery (71.73%) was realized in water-wet rock. However, in the CSHP method, the maximum recovery was lower (48.11%). It was believed that the temperature altered the wettability of oil-wet rock to more water-wet, which contributed to incremental oil recovery. However, higher steam injection temperatures greater than 140 °C had no significant effect on incremental oil recovery. Furthermore, asphaltene precipitation, especially in the oil-wet system and alteration of wettability to more water-wet increased oil production

Economics of Mining Assisted Heavy Oil Production (MAHOP) Method for Ultimate Recovery

The objective of this study is to compare the operating and capital cost of ultimate recovery from Turkey’s proven largest oil reserve (1.85 billion barrels), Bati Raman field by steam assisted gravity drainage (SAGD) and mining assisted heavy oil production (MAHOP) conceptually. Bati Raman field is located at an average depth of 1,450 m, producing from fractured limestone, having 12°API gravity and a viscosity of 200 to 2,000 cp heavy oil at reservoir conditions. Although 60 years passed on the discovery date of the largest oil field of Turkey, less than 8% of the reserve have been produced, increases the importance once more. One of the potential recovery methods is the MAHOP in which declines (tunnels) are excavated from the surface to the reservoir and continue along the reservoir depth. From the roof of the declines, fan shape up holes are drilled in the reservoir. The production of heavy oil through these tunnels are explored using well known SAGD method where in shallow sands it is possible to reach oil recoveries of 60%. The aim of applying MAHOP is to see if such recoveries are possible. MAHOP is expected to perform better due to less steam loss and better steam quality. The total average capital cost of MAHOP is estimated to be $2.75 billion US dollar including surface and subsurface facilities. Total capital costs for 60$/bbl, respectively. MAHOP operation cost is estimated to be 12 $/barrel. In contrast, in the SAGD case the total average capital cost is estimated to be$7.62 billion US dollar including surface facility and drilling horizontal well pairs. Total capital costs for 60% and 80% recoveries are 7.62 and 5.46 $/bbl, respectively. SAGD operation cost is estimated to be 20$/barrel. As a result, MAHOP is found to be more economical in terms of both initial investment and operating costs

Polymer gel conformance on oil recovery in fractured medium: Visualization and verification

Due to complexity and heterogeneity of the geological patterns of fractured reservoirs recovery estimations are considered to be extremely challenging. These fractures form complicated paths for reservoir characterization and fluid movement that ultimately impacts production performance and recovery

A study of steam-assisted gravity drainage performance in the presence of noncondensable gases

Traditionally, the addition of a non-condensable gas to steam is known to have a beneficial effect on heavy-oil production when conventional vertical wells are used. Little information and experimental evidence exists regarding the effect of the addition of such gases in the steam assisted gravity drainage (SAGD) process. The limited literature suggests that the addition of small amounts of such gases (e.g., carbon dioxide) may improve oil recovery. The gas accumulates at the top of the reservoir and provides a thermal and pressure insulation effect that in turn limits the rate of front spreading at the corners of the steam chamber. In order to investigate these phenomena, SAGD experiments with and without carbon dioxide injection were conducted in a physical model. It is packed with crushed limestone premixed with a 12.4° API heavy-oil. Temperature, pressure and production data as well as the asphaltene content of the produced oil were monitored continuously during the experiments. It was observed that for small well separations as the amount of carbon dioxide increased, the steam condensation temperature and the steam-oil ratio decreased. The heavy oil became less mobile in the steam chamber due to lower temperatures. Thus, the heating period was prolonged and the cumulative oil recovery as well as the recovery rate decreased. In this instance, the produced oil contained a relatively high concentration of asphaltenes. This supports the observation of poorer oil recovery as the fraction of carbon dioxide injected increased. A large asphaltene fraction in mobile oil serves to maintain high viscosity. On the other hand little or no change in oil recovery and oil recovery rate was observed for larger well separations regardless of the fraction of carbon dioxide in the injection gas. Similar behavior was observed when n-butane was injected along with steam instead of carbon dioxide. The impact of initial gas saturation (carbon dioxide or n-butane) was also investigated. It was observed that cumulative oil recovery, rate of oil recovery, and steam-oil ratio decreased independent of well separation compared to a reservoir with no initial non-condensable gas

The Effects of the Gamified Flipped Classroom Method on Petroleum Engineering Students' Pre-class Online Behavioural Engagement and Achievement

The flipped learning is a widely-used teaching method that increases the interaction between the instructor and the students by changing the in-class instructional time and the out-of-class practices. In this method, if students come to the class without studying the pre-course materials, this might lead to failures in its application. Besides, the gamified flipped learning environment was obtained by integrating the gamification elements in the pre-class phase of the flipped learning. The effects of teaching in this environment on students’ online behaviors and achievements were investigated. The participants were fourth-year undergraduate petroleum and natural gas engineering students enrolled in a natural gas engineering course. A true-experimental design was used in the study. Data were collected from a natural gas concept test, weekly quizzes, and data logs from Moodle. The research results indicated that teaching in the gamified flipped learning method showed a significant increase in the students’ participation in the pre-class activities of the flipped learning compared to the control group. Moreover, there was a significant increase in the achievement levels of the experimental group as compared to the control group. Based on these findings, the use of gamification elements in the pre-class phase of the flipped learning method can have a positive effect on the pre-course online behavior engagements of students. Furthermore, it was determined that it has a positive effect on the achievements of students who completed the method