1. INRODUCTION In recent times, volatility has been observed in oil and gas prices which has resulted in lower rig count and fewer wells being drilled. Consequently, engineers working in unconventional plays have lower margin of error while planning new wells and are under increasing pressure to minimize the projects costs. One important aspect of projects in tight plays is the well completion design and stimulation strategy. Hydraulic fracturing is typically used to create high permeability channels to have better reservoir coverage. Hydraulically induced fractures drive the well economics as drainage radius around wellbore is limited to their extension in low permeability matrix. Thus, reservoir and production engineers need to use the right tools and appropriate methodologies to predict hydraulic fracture half lengths. However, despite spending 20-50% of well cost on compatible completion and stimulation operations, hydraulic fracturing is a ARMA 18-1385 Geomechanics-based Hydraulic Fracturing Modelling for Tight Gas Carbonates: Case Study of Naushahro Feroz Field in Pakistan Soroush, H.; Ginty, W.; and Pan, C. PETROLERN LLC, Atlanta, GA, USA Ferguson, W.; and Bere, A. Rockfield, Swansea, Wales, UK Farid, S.M.U.; Ahmed, H.; Asghar, A.; and Hussain, Z. Pakistan Petroleum Limited, Karachi, Sindh, Pakistan Copyright 2018 ARMA, American Rock Mechanics Association This paper was prepared for presentation at the 52 nd US Rock Mechanics / Geomechanics Symposium held in Seattle, Washington, USA, 17–20 June 2018. This paper was selected for presentation at the symposium by an ARMA Technical Program Committee based on a technical and critical review of the paper by a minimum of two technical reviewers. The material, as presented, does not necessarily reflect any position of ARMA, its officers, or members. Electronic reproduction, distribution, or storage of any part of this paper for commercial purposes without the written consent of ARMA is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 200 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgement of where and by whom the paper was presented. ABSTRACT: Attempts to stimulate a partially fractured tight carbonate reservoir in the Naushahro Feroz field in Pakistan indicated that fracturing without sufficient understanding of the in-situ stresses and rock mechanical properties is a huge risk. These initial attempts included a matrix acidizing job followed by a pulsated proppant fracturing job and eventually an acid-fracturing job. Despite this, the resulting production rates were not sustainable. A geomechanical study was then carried out with the hope to improve the production from the tight reservoir. The study started with developing geomechanical models for the field, including both 1D and 3D models, using data from the vertical exploration well and its deviated side-track. The models were eventually updated using data acquired in the horizontal well drilled for stimulation. The geomechanical model, firstly helped to design and successfully drill the 1,300 m horizontal sidetrack; and secondly helped optimizing the zones selection and packer placement (10 zones) in addition to determining the maximum allowable drawdown to prevent wellbore failure during well testing. It also showed that the overlaying shale has potential to act as a weak containment. Both proppant and acid fracturing jobs were modelled based on the geomechanical data and concluded that proppant fracturing was a better option for this specific reservoir considering the elevated temperature, high fracture closure pressure, and the orientation of natural fractures to the well trajectory. However, due to risk of proximity of formation water level to the toe zone, it was decided to perform Closed Fracture Acidizing (CFA) in the zones closer to the water spill point. While this stimulation technique limits the fractures height growth, it maintains conductivity and creates longer etched fracture length by maximizing differential acid etching through fingering as well as acid retardation. Finally, based on the models, the optimum designs for each zone were proposed and the expected geometry (height, extension and orientation) were simulated using 3D geomechanical analysis.