Proppant hydraulic fracturing has been a successful stimulation method used to enhance production in sandstone reservoirs. But for fracturing carbonate formations, the possibility of the existence of natural fractures and the hardness of the rock can be challenging. This paper will elaborate on a carbonate-fracturing pilot project in Soka field, which is the leading carbonate proppant hydraulic fracturing project in Indonesia. Platform carbonate limestone from the Baturaja formation is the major component of Soka field reservoir. The platform consists of limestone with infiltrate mudstone/packstone and chalky limestone with poor porosity. The limestone mudstone/packstone lithology is dominated by mud, clay, and fine silt carbonates which results in the limestone becoming dirty and causes the low acid-solubility value of limestone in the field. Stimulation jobs were performed in two wells in Soka field. From log analysis, the carbonate formation in both wells shows a high shale content (20%) and low permeability (6 md). Acid-solubility tests performed on both well cores showed low acid solubility. Matrix acidizing was performed in both wells, but they still showed low influx. Well A, after being perforated and matrix-acidized, only produced 40 BFPD, with a 30% water cut and a high GLR 19,061 scf/STB. Well B, after being perforated and matrix-acidized twice, had very low influx from reservoir to wellbore. Proppant hydraulic-fracturing stimulation was performed in both wells using hydocarbon-based frac fluid and 12/18-mesh ceramic proppant. After being hydraulically fractured, Well A produced 165 BFPD at 18/64 inch choke, with 60% water cut and a GLR of 700 scf/STB, while Well B produced 173 BFPD at 25/64 inch choke, with a 0% water cut and a low gas rate. Production from both of these wells is maintained at the reservoir critical rate for each well.
Proppant hydraulic fracturing has been a successful stimulation method used to enhance production in sandstone reservoirs. But for fracturing carbonate formations, the possibility of the existence of natural fractures and the hardness of the rock can be challenging. This paper will elaborate on a carbonate-fracturing pilot project in Soka field, which is the leading carbonate proppant hydraulic fracturing project in Indonesia.Platform carbonate limestone from the Baturaja formation is the major component of Soka field reservoir. The platform consists of limestone with infiltrate mudstone/packstone and chalky limestone with poor porosity. The limestone mudstone/packstone lithology is dominated by mud, clay, and fine silt carbonates which results in the limestone becoming dirty and causes the low acid-solubility value of limestone in the field.Stimulation jobs were performed in two wells in Soka field. From log analysis, the carbonate formation in both wells shows a high shale content (20%) and low permeability (6 md). Acid-solubility tests performed on both well cores showed low acid solubility. Matrix acidizing was performed in both wells, but they still showed low influx. Well A, after being perforated and matrix-acidized, only produced 40 BFPD, with a 30% water cut and a high GLR 19,061 scf/STB. Well B, after being perforated and matrix-acidized twice, had very low influx from reservoir to wellbore.Proppant hydraulic-fracturing stimulation was performed in both wells using hydocarbon-based frac fluid and 12/18-mesh ceramic proppant. After being hydraulically fractured, Well A produced 165 BFPD at 18/64 inch choke, with 60% water cut and a GLR of 700 scf/STB, while Well B produced 173 BFPD at 25/64 inch choke, with a 0% water cut and a low gas rate. Production from both of these wells is maintained at the reservoir critical rate for each well.
As one of gas field producers located in South Sumatra Indonesia, the S field produced 70 MMSCFD as its peak production. It is a high pressure and high temperature gas impurities of 30% CO2 and 100-ppm H2S. The field has been producing since April 2010, with current recovery more than 50% of initial gas in place. Utilizing initial estimated OGIP (Original Gas In Place), the gas deliverability was predicted to last only until 2022. There are high uncertainties in estimating accurate reserves value due to lack of reservoir data such as reservoir pressure and SCAL (Special Core Analysis). Therefore, additional information such as SBHP (Static Bottom Hole Pressure) survey data and well optimization are essential to be conducted to narrow the uncertainties in reserves estimation and gas deliverability. Apparently, in 2018 and 2019 during CPP (Central Processing Plant) shut down for preventive maintenance activity, SBHP survey could be performed. Additional pressure data was utilized to update the OGIP analysis by combining several methods such as p/z analysis, flowing material balance, rate transient analysis and history matching of dynamic model analysis. The analysis shows conclusive result that there is significant increase in the OGIP and reserves, estimated 16% of additional gas reserves. To support enhance gas deliverability, the production network model was then created to evaluate existing production method. This updated system analysis showed significant bottleneck at the existing production system that limiting the production rate from the wells. As part of debottlenecking endeavor, temperature survey on the production system was employed to overcome the limited availability of pressure survey points in the system. Furthermore, the successful debottlenecking activity combined with temperature drop analysis resulted in 20% additional gas deliverability. This integrated evaluation and optimization also prolong the field lifetime until 2025. This paper describes some of the challenges and lessons learned during the evaluation and optimization in the high pressure and high temperature sour gas field.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.