Abstract

Production logging, especially in highly deviated, horizontal wells still exhibits challenges due to multi-phase, complicated flow regimes in undulating long well bores in open hole completions. Because of the advances in measurement technology and interpretation techniques, production logging objectives can be achieved in more challenging conditions; the improved confidence in the result is crucial to associated decisions and well interventions.

In this paper, we present four field examples that used the latest technological advances and the best practices in integrated production logging in horizontal wells with openhole completions using either coiled tubing or tractor conveyance. The first example detected a super-permeability zone and a changing water salinity profile in the wellbore. The second example identified crossflow in a shut-in multilateral well; subsequent workover revived the oil production to initial production levels. The third example provides a discussion of the effective design of tractor-conveyed horizontal production logging to identify water entry and define the flow profile. The last example relates the first use of a new, compact, integrated production logging tool that pinpointed water entries in a horizontal openhole completion. This compact production logging system provides comprehensive, continuous data for the analysis of complex horizontal flow behavior.

The results of these field examples show how the application of the latest advances in horizontal production logging operations can significantly improve our understanding of well behavior and reservoir characterization. Combining these advantages with effective remedial action and workover operations can increase production and extend the life of horizontal openhole producing wells.

Introduction

Increased water production is often a cause of reduced well performance and decreased oil production. Evaluation of well production performance is of vital importance for well placement. In addition, workover scenarios can be planned based on production logs. Flow profiles and water entry intervals provide valuable information for comprehensive knowledge of reservoir dynamics.

Effective well length required for well testing can be estimated using well performance analysis from production logging. It is needless to mention the significance of fluid entries detection. Once fluid entries are zoned and integrated with available reservoir and geological data, it results in much more accurate characterization.

The nature of segregated multiphase flow in horizontal wells makes conventional production logging tools - designed for vertical wells - deficient when used for accurate identification and quantification of flow regimes[1–4]. The integrated production logging tool string was developed in 1995 and several examples of oil/water flow in horizontal wells were published[3, 5].

This paper presents four field examples of oil- and water flow measurement with coiled tubing and tractor conveyance in openhole horizontal completions. Examples confidently pinpointed water entries and profiled flow, using two different integrated production logging tool strings. Because of different conveyances and flow conditions, logging and data acquisition were optimized in an effective manner. The challenges associated with wellbore conditions and data acquisition are also discussed. One example includes successful water shutoff and revitalization of the dry-oil well from a dead condition. Results also revealed valuable reservoir characterization data.

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