With the exception of some short intervals, the whole logged section of the Asmari is layered / bedded as it consists of alternating beds / layers of dense and porous limestone of different thicknesses. Most bed / layer boundaries are not so sharp and planar. They generally are uneven due to diagenetic processes. Sharp boundaries, which are picked in this part of the log, are in places where there is contact between marly/shaly and anhydrite parts. They regularly have a planar surface that is a characteristic feature of bed boundaries in a succession of marl and anhydrite. Some thin dense and resistive streaks were identified over the logged interval, at places in carbonates of Asmari. There are also some shaly/marly beds in these carbonates, causing some places to wash out in the Asmari part of the interval. As accuracy of structural dip is dependent on planarity and sharpness of bed boundaries, the layer / bed boundaries were then categorized into High Confidence and Low Confidence categories as far as their dips. (Fig. 6).
There are 55 bed / layer boundaries which are sharp and planar, hence categorized as high confidence for bedding dip and there are 33 less sharp and relatively uneven layer / bed boundaries, classified as low confidence bedding. Both LC and HC beddings were used to determine the structural dip .Based on both dip types, an average dip magnitude of 75 degrees can be taken for structural dip computation for the whole interval.. However, the structural dip is deduced to be 75 degrees towards S28W. These variations in the dip Azimuth could be attributed to several reasons. As mentioned above, the sedimentary structure of the Asmari formation is moderately complex due to diagenetic processes, which happen in carbonate sequences naturally, and have the potential for variations in dip angle. There are major variations in bedding dip and strike trends. These variations sometimes make it difficult to recognize the major structural trends. The inclinations of dip are normally low and vary between 55-90 degrees. The large spread in the dip Azimuth within the structural zones could be attributed to the existence of diagenetic variations in limestone. (Fig. 7,Fig. 8, Fig. 8,and Fig. 9).
A computer-based cross-section along a NNE-SSW plane was built in Strucview based on this dip data. Strucview deals with geological dip data; displays and can automatically group dip data into sets representing geological structures. The cross-section computation is accessible in groups. The cross-section displays some irregular bedding planes possibly demonstrating diagenetic alterations.
As a result, the structural dip data is an input for permeability analysis software and helped in understanding the reservoir structure, identifying and evaluating sedimentary features and fractures, visualizing the rock texture, and complementing coring programs. (Fig. 10,Fig. 11,andFig. 12).
Natural Fracture Characterization (Calibration data)
It is vital to know, is the reservoir fractured or non-fractured? If it is fractured, then what is the kind of fracture (open or closed) and what is its intensity? Are those fractures are single set or multiple sets and what is the fracture azimuth and strike? Solutions to questions like these support geologists and reservoir engineers to increase oil production.
The well test analysis is not sufficient in characterizing fracture properties.Fracture intensity and deep-rooted fractures widely growth risk of unexpected water production.Fractured reservoirs are a special type of hydrocarbon reservoir. They are commonly thick, porosity is mainly secondary, the distribution of porosity and permeability is irregular, production varies greatly, and they may or may not have a common hydrocarbon content. Fractured reservoirs show a great deal of difference in terms of: (1) the pores of the host rock may or may not contain hydrocarbons, and (2) reservoir potential may or may not be evaluated by conventional open hole logs .
Fracture analysis is a target of the FMS survey in the study well. To get the maximum knowledge on fractures, the images were interpreted in conjunction with open hole logs. Discussion on various fracture attributes is given in the following paragraphs:
In terms of morphology, fractures are classified into three categories; Major, Medium, Minor, open (continuous, discontinuous) and closed fractures. The traces of continuous open fractures are visible in all pads and have larger apertures comparative to discontinuous open fractures. The others have discrete fracture traces, which are not visible in all pads and are in some cases vuggy. In closed fractures, the trace is completely healed and a resistive halo effect is present in many cases (Fig. 13).
All the fractures that have continuous or discontinuous conductive traces are termed as open (conductive) fractures. Such fractures are found throughout the entire interval and are clustered in some places. These fractures have a discrepancy in their aperture look and trace continuousness across the wellbore. So, they are classified into three categories; major-open fracture, minor-open and medium-open fractures. Major open fractures have large apertures and are continuous across the wellbore. The minor-open fracture apertures are not as large as major open fractures, but their traces are still continuous. A number of discontinuous-open fractures have a vuggy appearance, which is what is commonly expected in carbonates due to the dissolution of the host rock along the fracture plane as a result of crossing fluid. (Fig. 13).
Fracture Strike and Dip
The FMI images discovered fractures in most zones of the Asmari reservoir. Altogether, 698 fractures were identified . Most of the fractures are plotted within the 20 and 50 degrees inclination circles of the stereonet. The open fractures with a 40 dip inclination toward N48W. The open fractures show a dominant, striking trend of N42E-S42W. Once studied in relation to the bedding dip data, it is found that open fractures tend to strike oblique, parallel and perpendicular to the bedding strike. It indicates that open fractures are oblique, longitudinal and transverse types (Fig. 14, Fig. 15,and Fig. 16).
Three open-fracture zones can be roughly distinguished in the interval based on some factors, including fracture density and the distribution of these fractures in the form of clusters. Statistical plots for the dips of open fractures in the Asmari formation fracture zones show a wide range of dips and dip azimuths, which can be considered as a sign for the presence of a fault near the well(Fig. 17 and Fig. 18).
Comparison between FMS and Thin section data from Cores
Image logs are recorded over more extended depth intervals and can be used to achieve structural, stratigraphic and sedimentary dip profiles. There are four intervals where the fracture attributes FMS are compared with the thin section data. Minor and medium open fractures partially cemented with calcite and anhydrite have good confirmation with fractures in thin section data at some intervals.
Image logs have provided oriented fracture data in in-situ reservoir conditions. Unfortunately, the core condition during core sampling is incredibly poor within the fractured zones and cannot be used to deliver consistent information. Lowly core retrieval resulting from the existence of fractures has made the straight core to log match tough in places. Thin sections of the cores are usually only taken in reservoir formations where, due to lithology type, there may be only uncommon bedding planes that provide the structural dip trend (Fig. 19,Fig. 20,Fig. 21,and Fig. 22).
The image logs show that there is a strong NE-SW alignment of fractures which is ‘transverse’ to the Bibi Hakimeh field structure. Drilling fractures and borehole breakouts visible on image logs give confirmation of the present-day in-situ stress directions. Due to the poor core recovery, there was some uncertainty in the distinction between natural and induced features.
Calibration of FMS fracture data with mud loss data in Highly Fractured Reservoir.
The fracture data from FMS is calibrated with mud loss data. The high density of fractures seen on FMS image logs in zone I has been confirmed by inspection of the mud loss data . The mud loss and fracture density of the image are accurately matched in Asmari reservoir. Accordingly,there is a strong match between cumulative fracture density and cumulative mud loss data. (Fig. 23).
In-Situ Stresses Analysis
The subsurface of the continental crust infrequently stays at hydrostatic stress condition, the strain state under which all points within the crust are exposed from all directions to equal stresses (s1 = s2 = s3). Conversely, such stress conditions are infrequently met in the earth's subsurface as many structural movements keep taking place in it. The bigger portion of the disturbance in the equilibrium in the stress state is contributed by the plates' movements that eventually result in the formation of regional stress system for the area confined by them. Nevertheless, sometimes the regional stress is totally overprinted because of stresses limited to a particual area. The cause of local stress system could be also related to the faults, folding, diapirism and then forth. The orientation of such local stresses could also be changed suddenly over small distances in any area.
The wells drilled in areas exposed to such sorts of unbalanced stress system often display two styles of borehole failures, shear failure and tensile failure, after the rocks drilled by them are swapped with the drilling mud. The rocks can tolerate both compressive and shear stresses but the fluid filling the borehole can stand only compressive stress and not shear stress. Accordingly, concentration of stresses takes place round the borehole wihin the types of hoop stress or tangential stress.Once the mud weight is simply too low (i.e., radial stress = mud weight minus pore pressure), the most hoop stress becomes much on top of the radial stress. Subsequently, a shear failure of rocks exposed to the borehole takes place, which is revealed within the variety of borehole elongation on the orthogonal calipers of FMS and as extended dim areas on the FMS images that are 180 degrees separately. On the opposing, when the mud weight is just too high, the radial stress rises and therefore the hoop stress decreases; so, rock nearby the borehole comes under tension and flops in tension; the fractures so formed are called drilling induced fractures. It is shown within the style of a fracture seen by the borehole images oriented at 180 degrees from another. 
Commonly, in vertical wells and those with minor deviations, the orientation of borehole elongation is united with the tendency of minimum horizontal stress. Likewise, the strike of drilling induced is ranged with the drift of maximum horizontal stress. On the other hand, it should not be the case with the deviated wells and particularly those wells that are not aligned with either of the two horizontal stresses. In such wells, orientations of borehole breakouts and drilled induced fractures may not represent the true orientation of the two horizontal stresses. It is because of the fact that all three principal stresses (vertical and two horizontal) act obliquely on the borehole. Schlumberger developed a methodology by which borehole breakouts and drilling induced fractures from deviated wells, in particular, can be inverted to stress tensors responsible for their formation.Borehole breakouts were observed in the well. The great common of these oval breakouts have their extensive axis oriented in an practically NW-SE direction. This indicates that the orientation of minimum horizontal stress around the BH-90 well is almost NW-SE and the orientation of maximum horizontal stress is NE-SW. This orientation of in-situ stress matches with the regional orientation of Zagros stresses (Fig. 24).
Subsequently, this reservoir, which consists of carbonates (limestone, dolomite and anhydrite), and rarely clastics (sand and shale). Bed boundaries are almost uniformly distributed throughout the logged interval. The layering in the lower part of cap rock logged by the FMS tool is mainly due to the concentration of conductive spots parallel to the bedding which form conductive seams and the existence of marly/shaly interbeds between anhydrite beds characterized by high rates of CGR. These marly interbeds have also affected the borehole condition by causing some major and minor washouts which are reflected in caliper readings. The occurrence of these shaly and/or marly seams and layers can be a result of impermanent variation in sedimentary environment conditions, which has led to the domination of clastic particle accumulation in a sequence of anhydritic beds (Fig. 24).
 Shariatinia Z., Haghighi M. ,Feiznia S. ,Hall, D. Levresse, G. Dehghani, A. Rashidi, M.(2013) Paleofluid analysis from fracture-fill cements in the Asmari limestones of the Kuh-I-Mond field, SW Zagros, Iran, Arabian Journal of Geosciences, 2013; 6(7):2539-2556, Springer, ISSN: 1866-7511. 2253942ja.
 Movahed, Z., Junin, R., Safarkhanlou, Z., Akbar, M. (2014). Formation evaluation in Dezful embayment of Iran using oil-based-mud imaging techniques, Journal of Petroleum Science and Engineering121 (2014)23–37 37.
 Movahed, Z., Junin, R., and Jeffreys, P. (2014). Evaluate the Borehole Condition to Reduce Drilling Risk and Avoid Potential Well bore Damages by using Image Logs, Journal of Petroleum Science and Engineering122 (2014)318-330.