International Journal of Oil, Gas and Coal Engineering 2013; 1(1): 7-15 Published online August 10, 2013 (http://www.sciencepublishinggroup.com/j/ogce) doi: 10.11648/j.ogce.20130101.12 Reservoir characterization of Habiganj gas field Islam Md. Shofiqul * , Jahan Labiba Nusrat Department of Petroleum and Mining Engineering, Shahjalal University of Science and Technology, Sylhet 3114, Bangladesh Email address: sho_fiq@yahoo.com (Islam M. S.) To cite this article: Islam Md. Shofiqul, Jahan Labiba Nusrat. Reservoir Characterization of Habiganj Gas Field. International Journal of Oil, Gas and Coal Engineering. Vol. 1, No. 1, 2013, pp. 7-15. doi: 10.11648/j.ogce.20130101.12 Abstract: Although Habiganj Gas Field is one of the best gas field with good reservoir characteristics but it is least analyzed. This paper presents the critical view on four wells (HBJ -7, HBJ-8, HBJ-9, and HBJ-10) of upper gas sand using wire line log data for further development. It is found from the analyses data that a thick zone (~40 m, depth between 1410 to 1450 m) of Bokabil Formation in well no. 8 HBJ-8 shows greater porosity (>43%) and permeability (5-16 D) which may be the indicators of a big fracture zone within the reservoir that yet to be noticed. The similar phenomenon also observed in HBJ-9 with laser thickness. The consistency in porosity and permeability of different wells shows that the reservoir of Habiganj Gas Field is well-sorted. However the stratigraphical model shows that the structure of Habiganj Gas field is almost symmetrical and trending SSE, which supports the structure of Surma Basin. The multi-log 3-D model shows both lithology and stratigraphy, which also resemblance with the lithology and stratigraphy of the Surma Basin. Keywords: Habiganj Gas Field, Surma Basin, Reservoir Characterization, Porosity, Permeability 1. Introduction Reservoir characterization is essential for a sound petroleum management purposing of improving estimation of reserves and making decisions regarding the development of the field. Characterizing a reservoir includes lithology, porosity, permeability, temperature etc. There are many different methods for determining petrophysical characteristics have been published in the literatures for but there is no single method that yields the most reliable answer. The accuracy of the reservoir characterization depends on the availability and reliability of data whereas there are many limitations in data acquisition. A model of a reservoir that incorporates all the characteristics of the reservoir that is pertinent to its ability to store hydrocarbons. Moreover, a model with a specific volume incorporates all the geologic characteristics of the reservoir and such models are used to quantify characteristics within the subsurface volume. These attributes include the structural shape and thicknesses of the formations within the subsurface volume, their lithology, and the porosity and permeability distributions. The model result can detect heterogeneity of the reservoir. However, the two parameters; porosity and permeability are stable in the near-geologic timeframe and do not change due to the movement of fluids or gases through any of the formations pore spaces. Habiganj Gas Field is located in the north-eastern part of Bangladesh, lies in Madhabpur Upazila under Habiganj district (Figure 1). From the gross estimation, it is found that the upper gas sand of this field lies at depth of 1320 m to 1550 m. Reservoir characters of this gas field preliminarily analyzed using empirical method by [1], but there is no detailed analysis yet to be done. We believe that it is one of the least analyzed structures in term of reservoir characterization and has an appeal to assessment its properties. In this paper we tried to i) figure out some distinguishing features which yet to be known using well log data of the gas field, iii) identify lithology and stratigraphy of different wells based on log data, iv) to analyze changes of different properties with depth of different wells, and v) visualize the entire gas field in three dimensional model. 2. Geology The Surma Basin is a dynamically subsiding [2] sub-basin of the Bengal Basin situated in the northeastern part of Bangladesh. Habiganj Gas Field lies in the southern part of the Surma basin. However, the Aeromagnetic explanation plot [3] indicates a steady deepening of basement towards the center of the basin and also reveals subsurface synclinal features and faults within the basin. Its