Real-Time Downhole Coiled Tubing Communication System Allows Optimized Well Intervention and Reservoir Evaluation - A Two Well Case Study from New Zealand

New Zealand is known for deep, highly deviated wellbores often causing difficult wellbore interventions. This paper will highlight several coiled tubing (CT) interventions successfully completed in New Zealand with the help of a CT conveyed real-time downhole communication system. Well A in the study is a highly deviated gas producer which was to be converted into a gas re-injection well. A CT acid wash was required to remove deposited scale from the wellbore followed by a production log. The particular challenge with entering this well, in addition to the total depth of 7,395m, was that previous attempts hung up in a damaged seal assembly at 6400m and 66 degrees hole angle. It was decided that real-time data transmission / logging could help to increase the chances of successful CT intervention. Well B was a newly completed monobore well that was programmed for hydraulic fracturing completion in three zones. Underbalanced perforation and pre-frac flow testing was accomplished using a CT system on each of the three zones to evaluate the well productivity. To provide an accurate depth correlation for the perforating operation and to optimize the reservoir evaluation process, a real-time CT conveyed down-hole communication system was selected and successfully run. In both case histories, real-time data from downhole tools was obtained by utilizing a small diameter conductor wire which is pre-installed inside the coiled tubing. With mechanical and electrical quick connectors attached on the bottomhole assembly (BHA), a data acquisition system on surface can obtain real-time information from the casing collar locator (CCL), the down-hole pressure and temperature gauges, proving very valuable information for both CT and reservoir engineers to optimize their operations. Additionally, the CT string, with pre-installed conductor wire, allowed logging tools to be attached, retrieving live data from down-hole and allowing an optimized logging program to be performed on the fly. This paper reviews the coiled tubing real-time down-hole communication system and discusses the benefits of running it over conventional coiled tubing by illustrating case studies of successfully running the system from above two wells.