Some case studies of temperature and pressure transient analysis in horizontal, multi-zone, intelligent wells

Accurate measurement of real-time temperature and pressure across the well completion interval(s) has become standard in the modern production and injection wells. The data is used for routine production/injection monitoring, well stimulation, enhanced recovery operations, etc. During the last decade both the number of wells permanently equipped with pressure and temperature gauges as well as the accuracy and sensitivity of the sensors has increased dramatically. Large volumes of data are now produced that is often not “mined” for all the embedded information. Moreover, technology developments are exacerbating this data management problem with the availability of ever more reliable sensors at a lower cost, let alone the development of more advanced sensors capable of measuring additional properties of the flowing fluid.

The ambition of the Digital Oilfield is to provide continuous optimisation of field production by real-time, well control and monitoring. However, the actual level of use made of these large volumes of data is still low.

Downhole temperature measurements are able to provide extensive information for supporting well production diagnostics and optimisation. Recent publications have demonstrated that transient temperature analysis (TTA) has a high information potential with the unique advantage of being able to quantify zonal in- or out-flow. This derives from TTA being less affected by wellbore storage effects while at the same time providing a distinctive “build-up” or “draw-down” response to the performance of an individual reservoir layer. This latter has proven to be a highly productive source of zonal well production information, either as a stand-alone data source or in combination with pressure measurements, across the production interval(s).

This paper will present examples of pressure and temperature transient analysis of downhole data from a real, multi-zone, intelligent well. It will discuss the qualitative aspects of sandface and wellbore pressure and temperature response along with their quantitative analysis to provide zonal, multi-phase flow rate allocation.

The paper will provide novel insights into downhole data analysis for a horizontal well producing from multiple intervals. They can be applied to quantitatively interpret either discrete or distributed temperature data, both with and without accompanying pressure measurements. Application of the workflow proposed here can immediately increase the “Added value” derived from intelligent well technology.