Evaluation of Mud Weight Using Safe Mud Window Concept Based on Well Log Data: A Case Study of Well OP-002 in the North Sumatra Basin Area, Indonesia

Buntoro, Aris and RAHMAD, Basuki and LUKMANA, Allen H and Asmorowati, Dewi (2021) Evaluation of Mud Weight Using Safe Mud Window Concept Based on Well Log Data: A Case Study of Well OP-002 in the North Sumatra Basin Area, Indonesia. Engineering and Technology, 1. pp. 248-267. ISSN 2809-6843

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Abstract

In the drilling operation of well OP-002 which is located in the North Sumatra Basin at a depth
interval of 2887 - 3186 m occurred partial loss, and caving at a depth interval of 500 - 1650 m,
where the drilling problem is caused by the use of inappropriate mud weight. Safe mud window
analysis is carried out by processing well log data to build PPFG (Pore Pressure Fracture Gradient)
and 1D Geomechanics model using several calculation methods. Furthermore, the results of the
calculation of pore pressure and fracture gradient are validated with well test data from the well
OP-002, so the safe mud window can be determined, and can be used as a basis in the analysis of the
drilling problems that occur. The optimum mud weight can minimize wellbore instability, with a limit
value that must be greater than the collapse pressure, but not exceeding the minimum insitu stress
limit. From the results of the mud safe window analysis, it can be concluded that at a depth interval
of 500 - 1650 m caving occurs, because the density value used is smaller than the shear failure
gradient, and at a depth interval of 1619 - 2829 m, the density value used is greater than Shmin. To
overcome this problem, a mud wight with a safe mud window concept is recommended, namely the
selection of the optimum mud weight to be used must be greater than the pore pressure and shear
failure gradient and does not exceed the minimum horizontal stress and fracture gradient values.
Keywords: Mud Weight, Safe Mud Window, Well Log

Item Type:	Article
Uncontrolled Keywords:	Mud Weight, Safe Mud Window, Well Log
Subjects:	Q Science > QE Geology
Divisions:	Faculty of Engineering, Science and Mathematics > School of Engineering Sciences
Depositing User:	ST., MT HATY INTAN PARAMITA
Date Deposited:	04 Apr 2023 02:37
Last Modified:	04 Apr 2023 02:37
URI:	http://eprints.upnyk.ac.id/id/eprint/33309

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