Diagnosis And Analysis Of Well Abnormal Performance Data In Dina Overpressured Gas Field

Due to well completion problems, the observed bottom-hole flowing pressure inproduction wells of Dina2overpressured gas field exhibited unexpected sudden drop,frequent fluctuation and inconsistent change with flow rates, which masked the truebehavior of production wells and caused risks in production evaluation andoptimization. With universal, everlasting poor quality of flowing data, identificationof abnormal data and restore well true behavior were crucial in well performanceanalysis.This paper presented a literature review on stress sensitivity in overpressured gasreservoirs and abnormal production data diagnostics. Stress sensivitity were excludedbecause it was not the cause of well abnormal beheavior. Production data diagnosticsbased on modern production decline typecurves were introduced in detail, includingthe development history and its limitations in analyzing Dina2gas well long-termabnormal performance.Based on natural gas PVT properties of Dina2overpressued gas reservoir, the“pressure”(nomlized pseudo-pressure),“rate”(nomlized rate) and “time”(materialbalanced pseudo-time) fuctions in modern production decline analysis were reduced,and simplified type curves and diagnostic plots were given for Blasingame declineanalysis and Agarwal-Garnder FMB decline analysis. These simplified diagnosticplots were convenient and time saving for field application.The methods for syn flowing pressure in abnormal behavior wells were presentedbased on gas well flow potential and dynamic reserves. Gas well flow potential wasforecasted with LIT (Laminar-Inert-Turbulence) flow equations. And gas welldynamic reserves were determined based on the flow behavior of multi-well boundedgas reservoir.In field application, the integrated procedure were introduced based on Dina2abnormal well performances anlysis, which included, in sequence, diagnosing andfiltering of abnormal data, normal data analysis, well analytical model generation, andwell flowing pressure synthesis in a multi-well bounded reservoir. Finally wellproduction evaluation and optimization were made for gas wells in Dina2field.