Semester

Spring

Date of Graduation

2009

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Petroleum and Natural Gas Engineering

Committee Chair

Yueming Cheng.

Abstract

The major factor influencing the increase of natural gas use is the rise in its global demand. Due to the relentlessly increasing demand, there have been improvements in the techniques and technology used in recovering natural gas from shale gas reservoirs, including drilling a horizontal well and hydraulic fracturing. One of the significant challenges associated with gas shale production is that it is difficult to reliably predict ultimate recovery and estimate reserves, leading to great risk in exploitation of these resources. The purpose of this research is to evaluate the current decline curve analysis techniques and provide a more reliable method for production forecast and reserve estimate for hydraulically fractured horizontal wells producing from gas shale reservoirs.;When production data of low permeability reservoirs are analyzed using Arp's equation, the decline exponent b which is supposed to range between 0 and 1 is usually greater than 1. The actual decline exponent b value is not easy to come by in the transient period during the life of the well, however, having a decline exponent b value greater than 1 will overestimate the remaining reserves of the well.;In this study, first, decline characteristics for shale gas wells are presented by simulating long-term production performance for a variety of well-reservoir systems, including Dimensionless fracture conductivity change, different fracture stages and fracture half-length; then different current decline analysis methods were evaluated in estimating reserves and predicting future performances. These methods are Conventional Decline Curve Analysis, the Backward Method and the Ilk Method. The evaluation task was done through quantitative comparison of production forecast results from current decline analysis with true simulated recovery.;Finally, the Backward & Ilk method was proposed and evaluated. This research work indicates that the Backward & Ilk method can provide the most suitable and accurate results in estimating reserves and analyzing production data.

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