This paper describes how a patented intervention based DTS logging system can be used to address the many and varied reservoir management challenges faced in declining fields, complex well profiles and complex completion methodologies. A description of the prototype system is provided along with the test results from the test well, and full suite of a Data Management System for Data Acquisition, processing and capabilities for Reservoir Flow Analysis. The paper closes with a draft overview of where this technology may be in the near future. Introduction The use of fibre optic sensing in oil and gas wells has been of interest to many operators since the first installations in the mid 1990's. Fibre optic sensing has mostly been in the form of Distributed Temperature Sensing (DTS), whereby a continuous length of fibre optic cable is incorporated in the completion tubing, generally encased in a small diameter umbilical. DTS used in this way has demonstrated value by providing information on flow allocation, well leakages, well integrity issues, water breakthrough and others. These applications form part of a new well construction and there is limited scope for retrofitting a well for permanent DTS monitoring. There is value to be gained by having an intervention system based on DTS technology. The project described in this paper takes the proven DTS technology and adapts it for use in a completion monitoring and production logging system. At present time, a lot of effort is made both by the industry players and research institutes to invent fibre optical sensing technology to be added to the system including point and distributed pressure, flow measurements and fluid phase identifiers leading to a complete fibre sensor based production-logging system. DTS sensors have been included in slickline type configurations but these systems, as with all wireline based systems cannot be deployed into highly deviated and horizontal wells without recourse to the use of a well "tractor". Despite becoming mature technology, these well "tractors" still suffers from difficulties getting into long reach high deviation well sections, not at least in open hole sections. They are also subjected to an increased risk of becoming stuck when going to these limits. Another challenge is that the toolstring length using such transportation device becomes very long, and that it requires extra personnel. The alternative is to deploy logging tools with coiled tubing, which is a comprehensive rig-up and deployment task. A challenge is also the dimension of the surface system and the handling of this, where rig-up often means 12–24 hours of lost production. Both the wireline and the coiled tubing operations requires a substantial amount of hardware, lifting operations and personnel, and it involves spooling up and down of wire or coiled tubing. This is a HSE issue as well as a high cost. And using these methods, conventional logging tools must be moved up and down to perform a survey of several zones, with necessary shut-in (lost production) during tool relocation. The new downhole sensing system described in this paper does not need to be relocated during surveying of several zones, which are time saving and a significant improvement in personnel safety. The dimension of the new ZipLog™ surface deployment system and the logging rod is of such a compact size, that rigup and deployment on wellheads having very limited headroom above are made possible. ZipLog™ allows surveying to be performed in wells where access with wireline has not been possible, replace wireline plugs in horizontal wellheads and to enable limited rig-up interventions. The method described in this paper utilizes DTS fibre optic cables embedded in a small diameter carbon fibre spoolable rod. The system has the attributes of a small diameter coiled tubing unit with the benefits of fibre optical based sensing along the whole spoolable rod.

This paper describes and demonstrates how a patented new wellbore intervention solution can be deployed in long horizontal wells holding Fibre Optic Sensing devices including DTS (distributed temperature sensing), Point Pressure and Motion sensors performing logging services to evaluate the Inflow Performance along the reservoir sections. The paper also provides a description of the intervention system with a short introduction on how the final system emerged from the idea stage. Also, we provide two Case Histories - a horizontal oil producer with 2-phase flow, and horizontal water injector. The planning- and operational execution phases are briefly described. The paper closes with a brief conclusion of what has been achieved and what more this technology may be able to in the near future. The methodology describes can be seen as a 3rd wellbore intervention method, in addition to coiled tubing (CT) and wireline. Introduction Known technology today for accessing long reach horizontal wellbore sections to perform logging and remedial work typically requires coiled tubing or wireline "tractor", where both these methods have constrains. Monitoring tools for use during fracturing and acid stimulation is also technology that is of limited availability (Ref SPE 106507). By adding Fibre Optic Sensing System to this technology we have been able to access horizontal wellbores for logging purposes demonstrating our capabilities to re-capture Inflow & Injection Performance evaluations similar to the today's conventional methods for Cased Hole Logging Services, where these tools also are used for Flow Interpretations in open hole sections. This paper describes the third well intervention method recognized in this industry developed and successfully applied to a number of wells. It is based on pushing a semi-stiff and spoolable carbon rod into production & injection wells. There is no similarity to logging tools that is added to the end of this conveyance method, but the logging results of reservoir behavior converted to Inflow Performance Analysis has been proven to be comparable.