Practical diagnostics using production data and flowing pressures

Three important advances in production-data analysis are the inclusion of flowing pressures into analysis methods; the use of a boundary-dominated equivalent-production-time function to make constant rate and constant pressure equivalent; and the use of pseudo-time, which corrects for gas properties varying with pressure. Their value depends on the quality of real production data and, more importantly, the analyst's ability to filter out the junk and retain the true reservoir signal. Blind application of decline-analysis methods without consideration of data-quality issues can lead to misinterpretation and erroneous results. Several practical diagnostic procedures, some general and others specific, can be applied to production data both on simple production charts and on advanced type curves.