Analysis of Linear Flow in Gas Well Production

Abstract

This paper was selected for presentation by an SPE Program Commdtee following rwew of information contahed in anqbstract submitted by the author(s). Contents cd the paper, as -fed. * n~~0 M* by Me .%cw@ d Petroleum Engineam and are subject to corr~on by the atithor(s) lle material, as presantad, does not necessarily reflect any position of the Sochty C4Ps4roleum Enginaars, its officers, or members Papers presented ad SPE meetings are subject to publication review by Editorial Commtiees of the Society of Petroleum Engineers Electronic reproduction, distitbution, or storage of any pati of ttws paper for mrnmercial purpasea wthout the wrilten consent of the Scmety of Petroleum Engineers is pmhibifd Permission to reproduce m print is restricted to an abstract of not more than S02 words, illustrations may not ba mpmd l%e abstract must contain conspicuous acknwhdgment C# where and by whom the paper was presented Write Librarian, SPE. PO, 130xS3S93%, Richardson. TX 7S0S3-3.536, U S A , fax 01 -972.9S2-943S AbstractLinear flow may be a very important flow regime in fractured gas wells. It is also important in some unfractured wells. This paper presents practical approach to analyze both pressure (well testing) and production rate (decline curve analysis) data which is influenced by linear flow, The paper explains two approaches to analyze the data (hand calculations and curve fitting). It uses analytical solutions that are adapted to different reservoir models. These models include fractured wells and wells producing reservoirs with high permeability streaks. Permeability, flow area, and pore volume may be obtained from either pressure or production rate data. The constant rate solutions are different from the constant pressure solutions, The use of the wrong equations in the analysis may result in errors as high as 600A,The paper also shows the application of these techniques in analyzing field data.

Simplified Forecasting of Tight/Shale-Gas Production in Linear Flow

“…Therefore, the equations presented here are based on the assumption of a constant flowing pressure at the well. Linear-flow theory El-Banbi and Wattenbarger 1998) indicates that at a constant flowing pressure, a plot of inverse gas rate vs.…”

“…7 into Eq. 6, the following equation is obtained for calculating the duration of linear flow and, hence, the beginning of boundary-dominated flow El-Banbi and Wattenbarger 1998):…”

Analysis of production data in shale gas reservoirs: Rigorous corrections for fluid and flow properties

“…The most popular method for analyzing linear flow is the square-root-of-time plot, a plot of rate-normalized pressure versus square root of time. It is documented in the literature that linear flow appears as a straight line on the square-root-of-time plot El-Banbi and Wattenbarger, 1998). Nobakht and Clarkson (2011a) showed that this is not true for constant rate gas production.…”

“…Linear flow theory El-Banbi and Wattenbarger, 1998) indicates that at a constant flowing pressure, a plot of inverse gas rate versus square root of time on Cartesian coordinates is a straight line. The slope of this line is used in the literature to calculate x f ffiffi ffi k p…”

“…, where x f is fracture half-length and k is the permeability, for gas using the following equation in field units El-Banbi and Wattenbarger, 1998):…”