Numerical reservoir simulation of Alaşehir geothermal field

Use of a comprehensive reservoir simulation is essential for an effective geothermal reservoir management. TOUGH2 has become a widely used simulator for this purpose. In this study, one of the most exploited geothermal fields in Turkey, Alaşehir geothermal field has been modeled by using TOUGH2 reservoir simulator. The study includes more than 100 wells, which are operated by 7 different developers. The total installed capacity of geothermal power plants in the field is 212 MWe, but additional capacity (98 MWe) is planned to be commissioned by the end of 2020. The proximity of licensed areas and strong well interferences have made the simulation necessary for a successful reservoir management. Different data sources including pressure transient tests, reservoir monitoring and tracer test data were coupled to construct a large numerical model, which has dimensions of 18 kmx12kmx5.5km. During model calibration, good matches were obtained between model results and actual decline in the reservoir temperature, pressure and noncondensable gases (NCG) production. The effect of planned power plants on the field performance is studied by performing scenario runs using maximum possible flow rates. Model results indicated that commissioning of new power plants and additional make up wells that will compensate missing production accelerates pressure decline to more than 3 bars/year

Changing Casing-Design of New Geothermal Wells in Western Anatolia for Adapting to the Changes in Reservoir Conditions

The traditional casing-design of geothermal wells in Western Turkey is no longer cost-effective and shortening wells’ production lifetime. The current reservoir conditions are much different from their initial values. Significant reduction of reservoir pressure and NCG (Noncondensable Gases) content have been observed in many geothermal fields in Western Turkey due to the construction of oversized power plants, aggressive production, and lack of unitized reservoir management. Thus, there is a need to adapt the casing-design of new production wells for the recent reservoir dynamics. A case study from the Alaşehir field, Western Turkey, is presented in this study. The proposed casing-design increases the performance and production lifetime of the artesian wells. It also enables the operators to use ESPs (Electrical Submersible Pumps) and LSPs (Line Shaft Pumps) with a large diameter for delivering large flowrates. With the new casingdesign, we also aim to prevent casing-collapse due to poor cementing job between 95/8” and 133/8” casings. A set of codes written in Python was used to construct the new casing-design. The effect of the proposed design on the performance of artesian wells is studied using a wellbore simulation program, an academic version of PIPESIM. ESPs are proposed for the new and traditional casing program in the field. The proposed design will give a good insight into the development of the depleted geothermal reservoirs

Site index conversion equations for mixed stands of scots pine (Pinus sylvestris L.) and oriental beech (Fagus orientalis Lipsky) in the Black Sea Region, Turkey

The site index conversion equations are important for estimating the site index of one tree species from the site index of another tree species in mixed stands. In this study, data were obtained from 162 sample plots in mixed stands of Scots pine (Pinus sylvestris L.) and Oriental beech (Fagus orientalis Lipsky) from the Black Sea Region in the north of Turkey. The breast height ages and height of the site trees were measured and the site index was estimated by these data. Geometric linear regression was used to estimate the parameters of a linear model relating to site indices of Scots pine and Oriental beech species. The correlation between the site indices of Scots pine and Oriental beech was 0.818, indicating a good fit to the linear model. Validation procedure showed that conversion equations were suitable for the studied mixed stands. The conversion equations can be applied to mixed species stands with inconsistent stratification or in stand conversion situations for an accurate and reliable evaluation of forest quality

Dynamic base-age invariant site index models based on generalized algebraic difference approach for mixed Scots pine (Pinus sylvestris L.) and Oriental beech (Fagus orientalis Lipsky) stands

Data from stem analysis of 397 dominant trees (198 Scots pine and 199 Oriental beech) were used to evaluate dynamic base-age invariant site index models derived from Bertalanffy–Richards, Hossfeld, and Lundqvist–Korf functions with the generalized algebraic difference approach (GADA) for mixed Scots pine (Pinus sylvestris L.) and Oriental beech (Fagus orientalis Lipsky) stands. These functions were compared with respect to residuals of these models; specifically, the evaluation criteria were bias (– root mean square error (RMSE), absolute mean error (AME), adjusted coefficient of determination (R2 ), and Akaike information criterion. The best results were obtained with generalized algebraic difference equations derived from the base models of Bertalanffy–Richards for Oriental beech and Hossfeld for Scots pine. These selected models accounted for 95%–96% of the total variance in height–age relationships in dominant trees with bias of 0.049841 and 0.00171, RMSE of 1.55624 and 1.353736, AME of 0.940128 and 0.884034, and AIC of 723.55 and 1250.78 for Scots pine and Oriental beech, respectively. These dynamic base-age invariant site index models for the 2 tree species presented more effective and accurate polymorphic site index curves with multiple asymptotes than earlier site index models for Oriental beech and Scots pine. The important differences of height growth trend between developed base-age invariant site index models in this study and earlier site curves were determined by graphical comparisons for site index predictions. Therefore, the new dynamic base-age invariant site index models developed based on GADA methodology can be recommended for dominant height prediction and forest site quality evaluations in the mixed stands of these 2 species

Karadeniz bölgesi sarıçam (pinus sylvestris L.) - doğu kayını (fagus orientalis lipsky) karışık mesçerelerine ilişkin sıklığa bağlı hasılat tablolarının düzenlenmesi

In this study, variable density yield tables were developed for Scots pine and oriental beech mixed stands in Black Sea Region. The data used in this study were obtained from 162 temporary sample plots measured in evenaged Scots pine and oriental beech mixed stands. The sample plots have 31-150 years for Scots pine and 33-117 years for oriental beech of stand age range, 16.2-34.9 m Scots pine and 14.7-32.3 m for oriental beech of site index range, 0.24-0.9 of Scots pine mixture ratio range, 2.9-10.0 of stand density range. With the generated equation systems, stand age, site index, density and mixture ratio of the four main factors in Scots pine -Oriental beech mixed stands, including the effects individual, dual, triple and quadruple of factor interactions on the stands were determined numerically. The results were in arrangement with the acknowledged growth rules.Bu çalışmada, Karadeniz bölgesinde yayılış gösteren Sarıçam-Doğu Kayını karışık meşcerelerine ilişkin sıklığa bağlı hasılat tabloları düzenlenmesi amaçlamıştır. Bu çalışmada, Karadeniz Bölgesi sınırları içerisinde yer alan eşityaşlı Sarıçam (Pinus sylvestris L.) - Doğu Kayını (Fagus orientalis Lipsky) karışık meşcerelerinden alınan 162 adet geçici örnek alandan elde edilen veriler kullanılmıştır. Örnek alanlar, Sarıçam için 31-150 ve Doğu Kayını için 33-117 yaşları, Sarıçam için 16.2-34.9 m ve Doğu Kayını için 14.7-32.3 m bonitet endeksi, 0.24-0.90 sarıçam karışım oranları ve 2.9-10.0 sıklık değerleri arasında değişim göstermektedir. Söz konusu bu veriler kullanılarak elde edilen regresyon denklemleriyle, Sarıçam-Doğu Kayını karışık meşcerelerinin yaş, verim gücü, sıklık derecesi ve karışım oranı olmak üzere dört ana faktörün bireysel etkileriyle, ikili, üçlü ve dörtlü faktör etkileşimlerinin meşcere yapısı üzerindeki etkileri sayısal olarak belirlenmiştir. Elde edilen bulgular temel ormancılık büyüme yasaları ile uyumludu

The Construction of Variable Density Yield Table for Scots Pine and Oriental Beech Mixed Stands in Black Sea Region

Bu çalışmada, Karadeniz bölgesinde yayılış gösteren Sarıçam-Doğu Kayını karışık meşcerelerine ilişkin sıklığa bağlı hasılat tabloları düzenlenmesi amaçlamıştır. Bu çalışmada, Karadeniz Bölgesi sınırları içerisinde yer alan eşityaşlı Sarıçam (Pinus sylvestris L.) - Doğu Kayını (Fagus orientalis Lipsky) karışık meşcerelerinden alınan 162 adet geçici örnek alandan elde edilen veriler kullanılmıştır. Örnek alanlar, Sarıçam için 31-150 ve Doğu Kayını için 33-117 yaşları, Sarıçam için 16.2-34.9 m ve Doğu Kayını için 14.7-32.3 m bonitet endeksi, 0.24-0.90 sarıçam karışım oranları ve 2.9-10.0 sıklık değerleri arasında değişim göstermektedir. Söz konusu bu veriler kullanılarak elde edilen regresyon denklemleriyle, Sarıçam-Doğu Kayını karışık meşcerelerinin yaş, verim gücü, sıklık derecesi ve karışım oranı olmak üzere dört ana faktörün bireysel etkileriyle, ikili, üçlü ve dörtlü faktör etkileşimlerinin meşcere yapısı üzerindeki etkileri sayısal olarak belirlenmiştir. Elde edilen bulgularIn this study, variable density yield tables were developed for Scots pine and oriental beech mixed stands in Black Sea Region. The data used in this study were obtained from 162 temporary sample plots measured in even- aged Scots pine and oriental beech mixed stands. The sample plots have 31-150 years for Scots pine and 33-117 years for oriental beech of stand age range, 16.2-34.9 m Scots pine and 14.7-32.3 m for oriental beech of site index range, 0.24-0.9 of Scots pine mixture ratio range, 2.9-10.0 of stand density range. With the generated equation systems, stand age, site index, density and mixture ratio of the four main factors in Scots pine - Oriental beech mixed stands, including the effects individual, dual, triple and quadruple of factor interactions on the stands were determined numerically. The results were in arrangement with the acknowledged growth rules

112Sn(α, ) 116Te reaksiyonu için astrofiziksel S-faktörlerinin ve reaksiyon hızlarının hesaplanması

Çalışmamızda 112Sn(α,) 116Te reaksiyonunun reaksiyon hızları hesaplanmıştır. Hesaplamalar için TALYS 1.95 kodları kullanılmıştır. Ek olarak, düşük enerjili bölgelerde bir reaksiyon olasılığını açıklayan astrofiziksel S faktörleri elde edildi. Hesaplamalarımızın sonuçları, EXFOR veri tabanından alınan deneysel verilere göre kontrol edildi.In our study, the reaction rates of 112Sn(α, ) 116Te reaction were calculated. TALYS 1.95 codes were used for calculations. In addition, astrophysical S-factors were obtained that explain the probability of a reaction in low-energy regions. The results of our calculations were checked according to experimental data from the EXFOR database

Artificial Lifting in Liquid Dominated High-Temperature Geothermal Fields in Turkey: Lessons Learned

Due to the attractive feed-in-tariff mechanism, Turkish geothermal producers operate geothermal power plants at their maximum capacity. As a result, many geothermal reservoirs in Turkey have been exploited with an aggressive production strategy by multiple operators. A significant amount of production targeted natural fractures associated with normal faults in Western Anatolia. Wells produced at the maximum allowable capacity caused substantial reservoir pressure drops that affected reservoir dynamics. Premature temperature decline, local pressure drop, and the sharp decline of non-condensable gases (NCG) have been commonly observed in these geothermal reservoirs. All of these impacted the production performance of wells negatively. Artificial lifting methods such as airlifting and downhole pumps (Line shaft pumps or electrical submersible pumps (ESPs)) are commonly used to compensate for missing production. This study discusses the use of ESPs in liquid dominated high-temperature Alaşehir and Kızıldere fields. Observations, experiences, and lessons learned from the ESP applications in these fields are reported in detail

Wireless Sensor/Actuator Networks in Precision Agriculture: Recent Trends and Future Directions

Agricultural production and water has critical importance for socio-economic development of the societies. Unfortunately, the underground water level is slowly falling down and forests are being cut which reduces the rainfall as well. Technological advances on sensor technology and wireless communication are leading to the appearance of wireless sensor/actuator networks (WSANs) in a variety of commercial, industrial and military applications. There is no doubt merging wireless sensor technology into agricultural facilities will make farming activities much easier. In this paper, we look at the role of WSANs in agricultural production. We also investigate the communication architecture of WSAN based large scale irrigation management system and explain the key issues that are faced in the system design. Thanks to the easy installation and maintenance of WSANs, lots of water can be saved by giving timely feedback from field to improve the agricultural irrigation efficiency. This kind of solution can greatly help farmers to monitor the amount of water applied to a fiel

Intelligent control of agricultural irrigation system based on wireless sensor and actuator networks

Optimizing water usage is the primary objective of intelligent and eco-friendly agricultural irrigation systems. In irrigation systems, the flow and pressure of water is usually regulated by controlling the position of the valve. The proportioning electronic actuator accepts a signal from the control system and moves the valve to allow the valve to partially open or close. Varying speed of pump motor can also control the usage of water. The integration of wireless sensor and actuator networks (WSANs) into irrigation management promises to overcome the excessive watering problem while providing additional functionality. This paper presents a case study on the use of WSAN for irrigation activities and investigates the application of fuzzy logic based valve aperture control. The results show that the proposed strategy can be effective in water flow control