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The well KKF-001 is an exploration well in the North Klamono Field, Salawati Basin which is located in the westernmost part of Burung's Head, West Papua with a gas reservoir target in the Kais Formation. From the mud log data of well KKF-001, it shows that at the depth interval of 98 – 345 ft, native clay mud is used. In the depth interval of 345 – 1985 ft, the KCl-Polymer mud system was used with a pH of 10, and at the depth interval of 1985 – total depth, the Sepolycol mud system was used. In the 0 – 4593 ft the depth interval are the Klasaman and Klasafet Formations which is dominated by shale with sandstone, limestone (820 – 1969 ft) insertions, and some coal inserts are found, especially in the 1969 – 3773 ft the depth interval. From the results of clay analysis using XRD from drill cuttings of KKF-001, it shows that in the 0 - 4593 ft the depth interval is dominated by Kaolinite and Illite minerals, which have the potential to cause cavings, hole collapse and time delayed failure. Kaolinite containing shale exposure to KCl mud system consistently produced a decrease in the rock strength, and causes the thermodynamic stability of the shale-forming minerals in contact with potassium ions to destabilize the Kaolinite. The correlation of XRD and MBT analysis with the shale category approach (Mondshine, 1966) shows an interesting relationship, namely the presence of Illite minerals and Mix layer, then the use of an inappropriate mud system will cause cavings. [ABSTRACT FROM AUTHOR]

The Bengkalis Trough is one of the largest sub-basins in the Central Sumatra Basin, where stratigraphically the Brownshale formation of the Pematang Group which is Eocene in age deposited in the lacustrine environment. The Brownshale typically contains medium to very good TOC, and type II / III kerogen. Based on previous research, the Brownshale formation was stated as the main source rock in Central Sumatra, so it has good prospects for shale hydrocarbon development. However, at the stage of developing shale hydrocarbon, a fracability model is needed which can be used as a basis for hydraulic fracking planning. This fracability model can be constructed using the correlation of the results of XRD and MBT analysis from drill cuttings of the well BS-03 that penetrated the Brownshale formation in Bengkalis Trough as a case study, because there is no core data available. From the fracability model, a depth interval dominated by brittle shale can be determined as the fracable zone interval. Based on XRD (bulk) analysis, it shows that the brittleness index at all depth intervals of the Brownshale formation (10420 - 11642 ft) is above 0.48 (brittle category), but based on MBT analysis, not all depth intervals are brittle shale. So that the MBT analysis can be used as a basis for determining the depth interval in hydraulic fracking planning, where in the depth interval of 11.020 - 11.350 ft (thickness = 330 ft as a sweetspot fracable window) is the most reliable fracability model, because it corresponds to the total gas interval (TG) of the composite log data. [ABSTRACT FROM AUTHOR]

The Well RHM-001 is an exploration well located in North Sumatra Basin. The drilling target is Baong Formation which has shale dominantly as its lithology. Based on drilling trajectory, the total depth to reach Baong Formation is about 3,400 m. According to the drilling report, caving and partial loss occurred at this well. To minimize drilling problems that might occur for upcoming wells and also to obtain the drilling target, the 1D geomechanics provides a PPFG model consists of pore pressure, fracture gradient, and horizontal stress, and shear failure gradient. Analysis results show the pore pressure is predicted using Eaton's method, fracture gradient is predicted using Daines' method, and minimum horizontal stress is predicted using Mohr-Coulomb Purely Friction Failure method, maximum horizontal stress is predicted using tectonic constant 1.2 known as strike-slip fault, and the shear failure gradient is predicted using Modified Lade Criterion method. Wellbore stability can be achieved as the safe mud window follows the common rule of Pore Pressure < Shear Failure Gradient < Mud Weight < Minimum Horizontal Stress < Fracture Gradient < Maximum Horizontal Stress. Based on the PPFG model, the stable mud weight recommendations are 9.1–16.3 ppg at a depth of 0–1090 m, 12.5–17.7 ppg at a depth of 1090–2554 m, and 14.6-17.9 ppg at a depth of 2554–3400 m. [ABSTRACT FROM AUTHOR]

Basin model study that discusses the importance of transforming smectite to illite/kaolinite as a source of changes in the brittleness of shale rock in the North East Java Basin which affect borehole stability in open hole conditions, is a very interesting challenge. The well BJN-004 is a development well located in the North East Java Basin Area where there are hole problems related to borehole stability, namely clay swelling at the upper depth interval, and caving at the lower depth interval. Based on the stratigraphy of the North East Java Basin, the source of shale lithology in the well BJN-004 are Lidah/Mundu, Ledok, Wonocolo, and Ngrayong Formations. Each of these formations has unique mineral characteristics according to its lithological characteristics, especially quartz and clay mineral content. In identifying the transformation of smectite to Illite/Kaolinite (clay diagenesis), mineralogy analysis (XRD) of drill cuttings data is carried out. The results of mineralogy analysis are correlated with lithological depth intervals, and drilling problems that occur. Clay diagenesis occurs due to the influence of high temperature and the presence of potassium in the sand-shale series. The North East Java Basin is generally dominated by shale lithology, and based on data from the drilling of the well BJN-004, it shows the presence of high temperatures starting at a depth of 4000 ft, where BHCT (bottom hole circulating temperature) has reached 1000C. The presence of dominant shale and high temperature allows the clay diagenesis process to occur in the area penetrated by the well BJN-004. From the results of the lithological correlation penetrated by the well BJN-004 with mineralogy analysis, it shows that there is a significant transformation of Smectite to Kaolinite starting at a depth of 4000 ft, which is also confirmed by the results of the MBT which shows that shale with the hard category is close to brittle, so it has the potential to cause caving. This is exacerbated by the presence of dominant Kaolinite, the use of KCl mud will make the shale more brittle. [ABSTRACT FROM AUTHOR]

At present, Indonesia has an immense shale hydrocarbon potential, where the Central Sumatra Basin is the biggest potential in Indonesia, especially from the Brown Shale Formation of the Pematang Group. However, the development of shale hydrocarbon in Indonesia is still little studied and poorly understood. Thus, research related to non- conventional hydrocarbon resources is fundamental in order to improve sustainable national energy security. However, further research must be carried out using analog outcrop data because there is no core from the Brown Shale Formation of the Pematang Group. Fortunately, there is currently very good analog outcrop at the PT. Karbindo in Kiliranjao, West Sumatra.In this paper, the sweetspot fracable window is determined by using a geomechanical analysis approach from core/analog outcrop samples so that the prospect formation interval model with a high fracable can be created, which correlates with fracture resistance and can be applied to determine the location and planning interval for hydraulic fracking. From the sweetspot fracablewindow of shale hydrocarbon, it is expected to increase success in producing shale hydrocarbons which have very low permeability by determining the exact location and hydraulic fracking interval, so that natural cracks can be opened and the fracture is connected to maximize hydrocarbon flow. [ABSTRACT FROM AUTHOR]