In most shale gas reservoirs in the US, horizontal wellsare drilled through the “reservoir” before beinghydraulically fractured at a series of discrete zones andplaced on production. The subsequent zonal gasproduction rates have proved highly variable andinconsistent with what are considered to behomogeneous shale gas reservoirs that have beenstimulated in the same way. Developing better modelsand optimizing completion and stimulation techniquesfor the next well requires identifying which zonesworked well, and which zones did not, in the last well.This leads us to the need for production logs.Production logs in shale gas wells are normally recorded30 to 60 days after the stimulation process has finished.In addition to the produced shale gas, the production logmust contend with semistagnant water trapped in thelateral section because of the wellbore trajectory.This paper looks at the wavy stratified and slug flowregimes that are expected in most horizontal shale gaswells and at one possible choice of sensormeasurements and sensor distribution for a shale gasproduction-logging toolstring.In the case of production logs in horizontal gas wells, anumber of interpretation steps need to be taken beforethe raw acquisition curves can be presented as amultiphase flow profile with zonal contributions. Thispaper shows examples of the workflow, together withsnapshots of the holdup and velocity profiles across thevertical pipe diameter and the resulting flow profiles.
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