The Lematang Block in South Central Sumatra have an estimated total reserve of 330 BCF, the expected production life of 10 years is of substantial importance to MEDCO the fields operator. Wells in this field contain 32% CO2, 100-ppm H2S, BHP of 10,500-psi and BHT 408 degF and are therefore categorized as HPHT gas wells. The initial two wells were completed by the previous operator using 22Cr tubular material and 13 Chrome based material accessories. However, operational difficulties from material deterioration were identified. Optimization of the completions durability with the consideration of the economics of the completions was of paramount concern when selecting the materials and the completion tool designs.

HP/HT gas wells, especially those in South Sumatra, Indonesia, present many challenges to exploitation operations due to a 408°F bottomhole temperature, a 10,500psi bottom hole pressure at some 11,000ft, and sour gas components of 34% CO2 and 100 –200ppm H2S. During the final stages of the completion of one such well, after setting the production packer a wireline run was made with .108″ slick line to recover the plug body from the seating nipple at 11.406ft. While pulling out and with the plug at 6000ft. the well became live without warning, blowing the tool string up the hole and, to contain the well, the drilling BOPs were closed shearing the landing joint which in turn closed the sub surface safety valve. Subsequently the well was successfully completed and prepared for wireline fishing operations. The wireline fishing operation went on for several days using .108″ wire, during which 45 runs were made with the recovery of only approximately 550ft of wire and so it was decided to call in heavy duty wireline fishing (HDWF) expertise to review the situation and make recommendations as to how to proceed. This resulted in a commitment being made to mobilize personnel and equipment from Aberdeen and the Middle East to carry out the required operations. In the meantime a total of 11 further runs were made in the well using coiled tubing which resulted in recovery of the upper part of the tool string and some additional wire. Fishing operations were recommenced using 7/32″ Supa 75 braided cable with two two/man crews providing 24 hour operation and a project leader located at the clients office to provide for direct liaison. After a total of 17 runs over 6 days of continuous operation, the fish was completely recovered and the well made ready for production. In this paper the authors will review the situation that was faced, the remedial work done to complete the well, the early fishing operations and the subsequent input of HDWF expertise. They will conclude with a detailed account of the successful HDWF operation – an excellent example of how careful planning, experienced personnel, dedicated project management and a collaborative relationship between the client and service company can lead to a successful outcome.

From the effect of global energy demands, many oil industries are forced to search for hydrocarbons in more challenging environments. For example, drilling under high pressure-high temperature (HPHT) conditions has become common practice over the past 15 years, and new technologies are being developed to keep up with the need to drill safely and efficiently, minimize formation damage, and improve the production rate. The decision to drill two highly deviated and horizontal gas wells in the "S" field located in South Sumatera, Indonesia led to a detailed drilling strategy for managing the HPHT - sour gas environment and the narrow pressure window. Subsurface simulation confirmed that these well designs will provide additional gas recovery compared to existing vertical wells and also extend the plateau time production accordingly. The main challenge was to connect two vertical wells into one horizontal that would contribute to 60% of gas recovery from this structure. Managed pressure drilling (MPD) was the main option for drilling this well in terms of drilling risk, compared to conventional techniques. The MPD method provides better control over formation damage along the horizontal section. Stimulating deep, hot, sour gas wells can be risky, and the chance of gas recovery is less when conventional drilling practices are used. Therefore, MPD coupled with the constant bottomhole pressure (CBHP) technique was chosen to fulfill the technical requirements. The initial well production test result shows that the MPD technique succeeded in minimizing drilling-related problems along with minimizing formation skin damage. This allowed the well to meet the proposed production rate targeted by the subsurface team. This paper describes the planning process for designing MPD HPHT drilling in a sour environment well and includes the implementation results and lessons learned from the drilling process.

HP/HT gas wells, especially those in South Sumatra, Indonesia, present many challenges to exploitation operations due to a 408°F bottomhole temperature, a 10,500psi bottom hole pressure at some 11,000ft, and sour gas components of 34% CO2 and 100 – 200ppm H2S. During the final stages of the completion of one such well, after setting the production packer a wireline run was made with .108″ slick line to recover the plug body from the seating nipple at 11.406ft. While pulling out and with the plug at 6000ft. the well became live without warning, blowing the tool string up the hole and, to contain the well, the drilling BOPs were closed shearing the landing joint which in turn closed the sub surface safety valve. Subsequently the well was successfully completed and prepared for wireline fishing operations. The wireline fishing operation went on for several days using .108″ wire, during which 45 runs were made with the recovery of only approximately 550ft of wire and so it was decided to call in heavy duty wireline fishing (HDWF) expertise to review the situation and make recommendations as to how to proceed. This resulted in a commitment being made to mobilize personnel and equipment from Aberdeen and the Middle East to carry out the required operations. In the meantime a total of 11 further runs were made in the well using coiled tubing which resulted in recovery of the upper part of the tool string and some additional wire. Fishing operations were recommenced using 7/32″ Supa 75 braided cable with two two/man crews providing 24 hour operation and a project leader located at the clients office to provide for direct liaison. After a total of 17 runs over 6 days of continuous operation, the fish was completely recovered and the well made ready for production. In this paper the authors will review the situation that was faced, the remedial work done to complete the well, the early fishing operations and the subsequent input of HDWF expertise. They will conclude with a detailed account of the successful HDWF operation – an excellent example of how careful planning, experienced personnel, dedicated project management and a collaborative relationship between the client and service company can lead to a successful outcome.

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