A Coupled Pseudo-pressure/density Approach To Decline Curve Analysis Of Natural Gas Reservoirs

Open Access
Author:
Gokhale, Jaidev Madhav
Graduate Program:
Energy and Mineral Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
November 21, 2014
Committee Members:
  • Luis Ayala, Thesis Advisor
  • Yilin Wang, Thesis Advisor
  • Shimin Liu, Thesis Advisor
Keywords:
  • Decline
  • Curve
  • Natural Gas
Abstract:
Natural gas is quickly gaining popularity as a clean and obtainable energy resource. With increasing exploitation of this resource the calculation of original gas in place (OGIP) becomes a crucial first step to developing natural gas reservoirs in a profitable manner. Once an estimate for reserves has been established key economic decisions can be made to maximize profitability from a given field. Furthermore, the calculation of OGIP serves to appraise reservoir value and influences key decisions on asset takeovers. Due to the importance of OGIP to influence key decisions of economics and asset development, careful consideration must be given into the development of techniques that are used to calculate OGIP. Decline curve analysis has been a preferred tool used by the industry to assist in the calculation of OGIP. This study reviews existing methods of decline curve analysis and provides a new, explicit method to calculate OGIP. The proposed approach demonstrates the ability to map the Arps decline parameters to a rigorous boundary dominated flow equation. Previously, the determination of Arps decline parameters relied predominantly on empirical methods. This study presents a physically justifiable approach to calculate the Arps decline exponent prior to the analysis of production data. Furthermore, the utilization of the mapped Arps decline parameters to predict OGIP using a straight-line analysis technique for cases of constant reservoir drawdown is also investigated through numerical and field case studies.