The influence of fractures in the production rate in carbonate reservoir of southern Iran has been established. The Gachsaran oil field is located in the Dezful embayment in SW of Zagros basin of Iran.The outcrop in the area mainly consists of Miocene- Pliocene Gachsaran formation evaporate and Aghajari classics. The main reservoir in this field is Miocene Asmari formation. Only upper Asmari is developed in this area, lower and upper Asmari is replaced by Oligocene-Eocene Pabdeh marly formation. In this study so also itself is a methodology, a new combination method has been established. Therefore, based on all possible methods and available data, the state of fractures intensity, orientation, type, spacing and etc. have been considered. More important of these methods that were used include the following: 1. Core analysis2. Open hole log analysis(such as FMS)3. Well drilling data analysis4. Structural analysis: fracture prediction base on stress and strain analysis5. Curvature analysis for a better geostatistical study, the Gachsaran anticline was divided in to thirteen different domains or blocks. Also some prediction and reservoir engineering data such as PI, RFT, BUT, maximum rate of production and permeability (K) parameters were studied and mapped. Later these maps correlated with other fracture analysis results. The correlations showed satisfactory results. Both flexural-slip and neutral surface folding mechanisms were active for this area. Regarding the prevailing mechanism of flexural-slip resulting in actives hear fractures in the present stress system, and the existence of gas-cap, the best areas of drilling for higher production are the flanks with thrust fault traces. The curvature analysis method, both in axial and cross sectional dimensions, together with stress-strain analysis are the best economical and powerful methods for exploration and development of oil fields. Also, the best geographical direction for drilling in some domains, based on fracture properties has been estimated.

Identifying reservoir rock types and their most significant vertical and horizontal heterogeneities is an essential component of reservoir characterization process, which are among the key input parameters in to a three-dimensional geological and flow simulation models. A reservoir classification and rock typing study were carried out on the Asmari formation of a mixed siliciclastic and carbonate reservoir in Iran. Detailed core analysis data including capillary pressure, core porosity, core permeability and core description supplemented by well logs revealed a complete vertical sequence of seven distinct clastic and carbonate reservoir rock types. Identification of the reservoir intervals and pay zones was carried out by means of the above results. Core based reservoir rock types were examined for each cored wells and log based reservoir rock types were selected and assigned in the uncured wells. The above data were applied as input parameters in a method based on Fuzzy Logic inference. The Fuzzy Logic technique was calibrated in 4 cored wells and blind tested in the other cored wells to determine the reservoir rock types. After the secondary calibration of the Fuzzy Logic against the core data, this technique was applied on 28 wells without any core data. The results reveal a very good match between the core data analyses and the Fuzzy Logic determination of the reservoir rock types. This technique can be applied to reduce the uncertainty of determination of the rock typing or as a very good predictor in uncured wells.

Sediment flushing of reservoirs is an operational technique, whereby previously accumulated sediments in the reservoirs are hydraulically removed by accelerated flow when the bottom de-silting outlets of the dam are opened. In this research, the process of sediment flushing is simulated by a three dimensional numerical model in which sediment and flow interaction are reflected in the reservoirs. Reynolds Averaged Navier-Stokes (RANS) equations are solved numerically by Finite Volume on a three dimensional grid and a standard k-e turbulence model is used. The resulting flow analysis is used as an input data for the sediment model. The convection diffusion equation for the sediment concentration is solved. The concentration equation derived by Van-Rijn is adopted as a boundary condition, resulting in a calculation of bed material load. The depth integrated mass balance equation is applied to find the bed changes. The results from the numerical model are compared favorably with the data from physical model studies available in the literature.

Drought is an inevitable part of the world s climate. It occurs in wet as well as in dry ‎regions. Therefore, planning for drought and mitigating its impacts is essential. In this ‎study, a hedging rule is developed using the zero/one mixed integer-programming ‎approach. Furthermore, some procedures are introduced to case the computational ‎burden inherent in integer programming. Hedging rules are developed using three, ‎two, and one-year historical droughts. Moreover, yield model (YM) along with the ‎standard operating policy (SOP) are also formulated for comparison purposes. ‎Simulations are carried out using 40 years of monthly historical data along with 20 ‎series of synthetically generated inflows of the same length. The Karadj reservoir ‎located in the northwest of Tehran is the major source of the capitals municipal water ‎supply. It also provides a substantial portion of the irrigation demand of the Karadj ‎Valley. Synthetic data are generated using single and mufti-variate autoregressive ‎modeling approaches. Models arc compared using important reservoir operation ‎criteria including reliability, resiliency, and vulnerability. As compared to the well-‎known SOP model, it is noticed that the application of the hedging rule and the yield ‎model substantially reduces the system reliability as well as its vulnerability, however ‎it increases the resiliency. Moreover, hedging rules developed using longer drought ‎periods tend to have lower vulnerability and reliability, and higher resiliency‏.‏

Both Asmari and Bangestan reservoir rocks have very complex fracture orientations. Such orientation patterns cause both oil ratio and internal pressure to be high in overall Gachsaran oil wells. The length of fractures in the reservoir rocks ranges from few centimeters to few meters in size.Variation of oil production from two different flanks of regional anticline suggests very complex fracture orientation patterns. Core analysis and mud logging information indicate macroscope fractures ranging from 2 to 5 meters in length. Some reports also indicate macroscopic fractures are common in Asmari formation and generally are formed by two different tectonic stresses. In the first stage, fractures formed by compressive forces and in the second stage by stimulation forces. Rock analysis indicates that Pabdeh, Gurpi and Ilam formations are very brittle and lateral fractures in Asmari and Bangestan reservoir formations are highly connected. As a result, gas injection in the Asmari formation will increase the pressure in the Bangestan reservoir rock.

In this paper, a procedure is developed which can be used to identify the natural frequencies and Natural modes in vacuum of an Arch-Dam from forced vibration testing data of partially filled reservoir. The effect of hydrodynamic pressure is removed by using an efficient algorithm. To verify the procedure, a simple structure is substituted for the dam with known properties in vacuum. Then a thin SSSF-plate is considered as the retaining wall representing of the dam and a sub-structuring technique is used with regard to a three dimensional linear compressible inviscid fluid body. The calculated resonance in the illustrated example replaces the resonance which in practical in-situ has been measured. Also the effect of the wave absorption at the bottom and bank of the reservoir is considered. The hydrodynamic pressure of the reservoir is calculated using boundary element method. The results which derived by solving an inverse problem, are compared with the exact analytical responses of the plate.