Production decline analysis and forecasting in tight-gas reservoirs
Mujeeb Khan Habib Mahadik A , Hassan Bahrami A , Mofazzal Hossain A and Tsar Mitchel ACurtin University
The APPEA Journal 52(1) 573-580 https://doi.org/10.1071/AJ11045
Published: 2014
Abstract
Exponential decline curve analysis is widely used to estimate recoverable reserves due to its simplicity. In most cases, however, an exponential model cannot provide a satisfactory match of overall production history. The generalised form of a hyperbolic decline model is more powerful in matching production history than the other decline models, but it is difficult to apply in practical production data analysis since it requires predicting two unknowns as decline constants.
Although a hyperbolic model may provide a good fit to early-time production decline data; it may overestimate the late-time production, especially for hydraulic fractured wells in a tight-gas reservoir. In fact, the exponential decline model might be more reliable for forecasting the late-time production.
This paper presents a practical approach to production decline analysis for non-fractured and fractured wells in a tight-gas reservoir using numerical simulation. Some production rate functions and type curves are introduced to obtain the best matching values of hyperbolic, exponential and harmonic production decline constants.
The simulated production rate decline data for various well and reservoir parameters are used to indicate the optimum time duration of use of each decline model and to show the time when the production decline starts following the exponential model. The proposed approach is applied in production data analysis and forecasting for a tight-gas field in WA. The results showed good agreement with the production forecast obtained from a reservoir simulation.
Mujeeb Khan Mahadik is a petroleum engineering graduate from Curtin University (Perth). Prior to this, he had completed a bachelor’s degree in mechanical engineering from Curtin University (Sarawak, Malaysia). M.Mahadik@postgrad.curtin.edu.au |
Hassan Bahrami is a PhD candidate in the Department of Petroleum Engineering at Curtin University, and is now focused on tight sand gas reservoirs’ damage and productivity. Prior to Curtin University, he worked for Schlumberger Data and Consulting Services (DCS) as a borehole reservoir engineer (2003–09), and at Tehran Energy Consultants as a reservoir engineer (2001–03). Hassan holds a BSc in chemical engineering from Persian Gulf University, and an MSc in reservoir engineering from Sharif University of Technology, Tehran, Iran. Hassan.Bahrami@postgrad.curtin.edu.au |
Dr Mofazzal Hossain is a senior lecturer, postgraduate course coordinator, and SPE faculty advisor at the Department of Petroleum Engineering in Curtin University. He has more than 14 years of experience in teaching, research and consulting work, with a major focus in the areas related to well technology and petroleum production technology. He has worked with the University of Adelaide and UNSW, Saudi Aramco and the King Saud University in Saudi Arabia, and the Reservoir Engineering Research Institute (Palo Alto). His research and works encompass reservoir stimulation by hydraulic fracturing for improved production from unconventional tight/shale gas reservoir, completion optimisation, rock fracture mechanics and wellbore stability. Dr Hossain received his PhD in Petroleum Engineering from UNSW. Member: SPE and IEA. Md.hossain@curtin.edu.au |
Tsar Mitchel is, at present, pursuing a Master’s degree in petroleum engineering from Curtin University (Perth). He had a brief stint with Kenya Electricity Generating Company Ltd as an exploration geophysicist before joining the National Oil Corpoation of Kenya as a petroleum geophysicist. He holds a Bachelor’s degree in geophysics. M.Tsar@postgrad.curtin.edu.au |
