Exercise-3(Fetkovich)

DataNet pay thickness (h)32ftWell bore radius (re)0.365ftInitial pressure (pi)3500psiapesudo pressure ( at initial)8.32E+08psia2/cpBHFP500.00psiapseudo pressure ( at pwf)2.11E+07psia2/cpreservoir temperature (T)1800F6400RWet gas gravity (Air=1)0.689Water saturation (Swi)0.34Water compressibility (Cw)3.60E-06psia-1Formation compressibility (Cr)4.00E-06psia-1Porosity 0.12Gas viscosity (at init. pressure)0.02095cpGas FVF (at inti. pressure)0.8174Total compresibility (Ct)1.57E-04psia-1

Producing Time (Days)Cumulative Production (MMscf)Gas Flow rate (Mscf/day)3013.4589413.36025.3066392.89036.3221375.912047.815371.315060.7706377.518071.1327367.821080.6358356.824090.3544349270105.643361.7300113.646349.1330122.878341.9360138350.1390142.779333.6420147.511291.4450168.504338.2480175.674329.1510183.737322.5540198.204327.1570199.765310.9600215.121316.6660230.559305.6720248.155298.7780264.898291.6840287.17290.8900296.938278960327.427284.81020341.435276.91170376.068259.91200379.859254.81320416.501249.41410426.793236.11500458.434237.41620482.743230.11710508.14224.21800531.01219.41980554.58199.92070575.818202.12190601.082196.42280626.139189.82310635.765190.52400648.646183.82580678.628176.42700702.659170.32880722.806143.72910735.055156.13000742.635154.63400791.57139.63600835.583138.14000881.494123.44200914.202120.54800981.543105.15000997.61998.554801046.0191.1

Step-1 (Matching Cumulative Production data to the best fitting curve)It is evident that boundary dominated data is present because data falls on right hand side of the inflexion point, therefore we can record particular b value by matching this data with type curveStep-2 (Recording re/rw and b)From the transient data which falls left to the inflexion point , re/rw is calculated to be 800 whereas, form the boundary dominated flow data, b matches to the value of 0.4Step-3 (Force a fit of rate/time data)After calculation of re/rw and b, Rate/time data is matched by forcing a fit of this data on the type curve having re/rw = 800 and b=0.4Step-4 (Calculation of permeability, k)After forcing a fit of rate/time data , we need to pick any match point on q(t) and qDd. For simplicity q(t) = 1000 MScf/day and qDd = 2.8. We can calculate k with the formula given on next page:q(t)1000Mscf/dayqDd2.8psc14.7psiare/rw800Tsc520Rankinek0.08mdStep-5 (Calculate initial surface gas flow rate)Initial surface gas flow rate qi at t=0 from the rate match point is calculated as:qi357.14Mscf/dayStep-6 (Determination of intial decline rate)From the same matched rate/time data, obtain any matched values of t and tDdt100daystDd0.034Initial decline rate , Di, is calcualated as:Di0.00034per day0.1241per yearStep-7 (Calculate reservoir Vp)Vp1.42E+07

Step-8 (Calcualtion of reservoir drainage radius)Assuming a circular drainage area, drainage radius is calculated as:re1085.29ftStep-9 (Calculation of Drainage Area)A3.70E+06ft284.95acresStep-10 (Calculation of Skin)Skin is calculated with the help of following formula:s-1.31Step - 11 (Forecast for next 15 years)By Extrapolating rate time curve, we cam obtain future rates with the help of following generalArp's Deccline Curve equation:We have the following parameters:qi357.14Mscf/dayb0.4Di0.00034per day0.1241t16-30 yearsFlow rates for next year are forecast as:t (in years)t (days)q (Mscf/day)16584082.8217620577.3618657072.3919693567.8520730063.7121766559.9122803056.4123839553.224876050.2425912547.526949044.9727985542.63281022040.45291058538.42301095036.53Step-12 (Economic age of the well in days or years)q (Economic limit of the well)30Mscf/dayagain by using following equation:t12450.83days34.11yearsStep-13 (Calculate Cumulative production upto Economic Limit of well)

Gp1354616Mscf1355MMScf

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