Field application of an interpretation method of downhole temperature and pressure data for detecting water entry in horizontal/highly inclined gas wells

摘要

In the oil and gas industry today, continuous wellbore data can be obtained with highprecision. This accurate and reliable downhole data acquisition is made possible byadvancements in permanent monitoring systems such as downhole pressure andtemperature gauges and fiber optic sensors. The monitoring instruments are increasinglyincorporated as part of the intelligent completion in oil wells where they providebottomhole temperature, pressure and sometimes volumetric flow rate along thewellbore - offering the promise of revolutionary changes in the way these wells areoperated. However, to fully realize the value of these intelligent completions, there is aneed for a systematic data analysis process to interpret accurately and efficiently the rawdata being acquired. This process will improve our understanding of the reservoir andproduction conditions and enable us make decisions for well control and wellperformance optimization.In this study, we evaluated the practical application of an interpretation model,developed in a previous research work, to field data. To achieve the objectives, we developed a simple and detailed analysis procedure and built Excel user interface fordata entry, data update and data output, including diagnostic charts and graphs. Byapplying our interpretation procedure to the acquired field data we predicted temperatureand pressure along the wellbore. Based on the predicted data, we used an inversionmethod to infer the flow profile - demonstrating how the monitored raw downholetemperature and pressure can be converted into useful knowledge of the phase flowprofiles and fluid entry along the wellbore. Finally, we illustrated the sensitivity ofreservoir parameters on accuracy of interpretation, and generated practical guidelines onhow to initialize the inverse process. Field production logging data were used forvalidation and application purposes.From the analysis, we obtained the production profile along the wellbore; the fluidentry location i.e. the productive and non-productive locations along the wellbore; andidentified the fluid type i.e. gas or water being produced along the wellbore. Theseresults show that temperature and pressure profiles could provide sufficient informationfor fluid identity and inflow distribution in gas wells.