This paper details the first implementation of a deep-set downhole hydraulic lubricator valve (DHLV) in Indonesia. This application was implemented in Jambaran field, onshore Central Java as part of Jambaran-Tiung Biru (JTB) national strategic project. Jambaran is a large carbonate gas field development located in proximity to densely populated areas. Since the field's reservoir contains significant concentrations of CO2 and H2S, it was important to design the completions to be able to perforate and test the wells safely without endangering the surrounding area. To produce as per reservoir management strategy, 800 ft of reservoir section drainage was required. Multiple completion designs were considered in the initial stages which included consideration of an open hole completions design, multiple wireline perforating runs and a cased hole live well single trip coiled tubing gun system. The rigless single trip coiled tubing gun deployment system was chosen due to safety and efficiency factors. With a deep set DHLV as the primary barrier in controlling the wells following perforating substantial daily rental cost savings can be realized during perforating operations. JTB field was developed by drilling 5 new well plus 1 re-entry well. The completions design was similar in all 6 wells. A 2 step completion design was utilized, to compensate for life of well tubing movement load, this consisted of a polished bore receptacle and production packer assembly in the lower completion. The 2nd stage of the completion consisted of 7" × 5-1/2" tubing with Tubing Retrievable Safety Valve (TRSV), DHLV, Permanent Downhole Gauge (PDHG) and production seal assembly. Strategically placing the PDHG below the DHLV enabled monitoring of bottom hole pressure during shut in without use of memory gauges validating the DHLV as primary barrier during gun retrieval. The production seal assembly was tied back into the lower polished bore receptacle that was previously set. The deep-set DHLV enabled the operator to (i) safely run long TCP gun assemblies up to 911 ft of gross gun length per well to perforate the whole well in 1 trip, (ii) POOH guns efficiently with one time bleed off (iii) efficiently initiate the pressure build up phase by shutting in the well against the DHLV as opposed to a surface valve prior to flowing the well and (iv) gun assemblies retrieved without the need to kill the well. After completing and well testing all 6 wells, the benefits of implementing the deep-set DHLV was immediately realized. By perforating underbalanced, omitting the well kill process and immediately proceeding with pressure build up by closing the DHLV resulted in operator savings of approximately 1.5 million USD over the entire rigless completion campaign.

As part of the strategic initiative to develop main reserves in Jambaran field in East Java, Indonesia, to supply gas and drive the national economy, six gas producers were completed targeting 300 MMscf/D of total production. The main challenge consisted in efficiently perforating underbalanced a minimum of 800 ft in each well. To this end, coiled tubing (CT) equipped with fiber optic (FO) and deployment under pressure were implemented, rigless; this was a first in the country. Understanding of zonal contribution in those long intervals early in the life of the wells was key to addressing any potential concerns over reservoir productivity and critical to the field management. Due to the high CO2and H2S contents of formation fluids (up to 34% and 10,000 ppm, respectively), traditional production logging was impossible. Instead, distributed temperature sensing (DTS) and downhole pressure point measurements through FO CT telemetry were jointly used to compute the flow distribution along each perforated interval. The acquired data were inverted and analyzed using a pressure-temperature-rate transient analysis (PTRA) software. In this field, reservoir K is a carbonate formation with a net thickness of ~1,450 ft and an average permeability of 46 md. Gas rates up to 60 MMscf/D were expected in each well. In such extreme downhole environment, DTS on FO CT was selected due to the possibility to circulate inhibitor throughout the operation to protect the CT pipe and downhole equipment. In addition, it enabled logging at gas rates as high as 60 MMScf/D without CT movement, which would not have been possible using wireline or slickline conveyance. In each well, a series of carefully planned shut-in and constant flowing phases were performed, during which temperature profiles and point pressure data were interpreted both qualitatively and quantitatively. A representative thermal model was built in the PTRA software utilizing reservoir properties, downhole point measurements, and surface well test data. Quantitative DTS interpretation indicated the same behavior in all six wells, with an uneven gas production along the perforated intervals. The minimal contributions observed from the upper section of the formation were attributed to low permeability whereas the high pressure drop observed across the bottom section was found indicative of a higher skin. Those findings will be key to future field developments in reservoir K. The use of CT equipped with FO for DTS proved a reliable alternative to production logging in high-rate gas producers. This study provided critical insights on the completion strategy performance and new considerations to minimize formation damage during future drilling campaigns. It also enabled establishing new best practices for DTS production logging in high-rate producers, in particular with respect to recommended drawdown conditions to obtain reliable readings.

Coiled tubing (CT) equipped with fiber optics and real-time downhole telemetry and a fit-for-purpose CT tower were used in underbalanced perforating operations in six wells in Indonesia; each operation involved 800 ft of perforating guns, and each was completed in a single trip. The reservoir is thick, with high permeability and characterized by high content of CO2 and H2S. The underbalanced perforating technique was deemed fundamental to minimize formation damage in the near-wellbore area, and the campaign was part of a national strategic project to develop a block's main reserve to supply gas to drive the national economy. Each well had to be completed with minimum of an 800-ft perforation interval to deliver an average of 60 MMscf/D gas production for 16 years plateau with up to 34% CO2 content and 10,000-ppm H2S. The traditional method of e-line overbalanced perforating in such harsh environment became inefficient because of the number of runs required, which can be as high as 40 runs per well. CT-conveyed perforating guns and a completion insertion retrieval of equipment under pressure (CIRP) system were chosen to execute the task. The fiber-optic CT real-time telemetry system was selected to improve downhole depth accuracy, confirm the underbalance condition, and provide real-time confirmation when the 800 ft of guns detonated downhole. To execute the six-well campaign safely, a customized 100-ft CT tower was brought into the country. Because this was the first in-country application for fiber-optic-enabled CT in single-trip with an 800-ft underbalanced perforation interval, thorough planning and preparation were critical for a successful campaign. Considering the high gas rate, high CO2, and H2S content, a downhole lubricator valve was added as additional barrier during undeployment, and an H2S and CO2 inhibitor was used to protect CT string integrity. Another risk mitigation plan was to utilize real-time CT inspection to monitor the CT integrity and condition throughout the job. Slickline deployment was used in first two wells to deploy multiple guns into the well, but this was deemed inefficient. The CT deployment method was used to complete the campaign. The project comprised a total of 2,200 operating hours, 29 CT runs, and 4,969 ft of guns in six trips with 917 ft as the longest interval. All six wells were completed with no HSE events, no automotive incidents, 98% operational efficiency, and 21% faster than planned duration. This successful six-well campaign represents a first in-country application, which contributed to developing this main gas reserve. The campaign provides lessons for job planning and preparation, technology implementation, execution, and continuous improvement, which can be implemented in similar projects in Indonesia and around the region.