A Hydraulic Fracturing Application To Overcome a Near Wellbore Damage in a High Permeability Formation

Abstract

In contrast to the common use of a hydraulic fracturing treatment in low permeability formations, recent advances of these treatment have overcome the limitations of matrix acidizing treatments performed in high permeability formations common to Indonesia. Being gravel packed with 5 Darcy permeability formation, WIA-8 well showed lower than expected productivity after completion. Efforts to restore the well productivity using matrix acidizing treatments resulted in additional productivity impairment. Recently, the well was worked over and the formation was treated with a small volume, high concentration, propped fracture treatment which successfully rectified the impairment. This is believed to be the highest permeability formation ever hydraulically fractured. This paper will outline the methodology used to design and perform a hydraulic fracturing treatment in high permeability formations. INTRODUCTION Widuri field is 90 miles (145 kms) north of Jakarta in the Java sea. The field is located on the northwest flank of the newly developed Asri basin (Figure 1). The field was discovered in April 1988 vkaen Widuri-1 well was drilled to a total depth of 3735' subsea and encountered 170' of net oil pay in the Talang Akar sandstone formation. The field structure is a faulted anticline formed in the early Miocene age shortly after deposition of the sandstone formation. The trapping mechanism is both structure and stratigraphy with hydrocarbon deposits found in six immature fluvial or distributary channel sandstone formations from 3200' to 3700' subsea depth1. Most Widuri wells are gravel packed initially in an individual sand formation and produced using electrical submersible pumps. The subject of this paper, WIA-8 well, is gravel packed in the 35-1 formation which is unconsolidated sand with a log porosity of 29% and a test permeability of 5 Darcies. After completion, some Widuri wells had experienced a productivity impairment. In August 1990, laboratory analysis was commenced to investigate the cause of the impairment and to determine an appropriate treatment. The results lead to performing subsequent matrix treatments on the WIA-8 well (Figure 2). In February 1992, a hot solvent treatment pumped into the well resulted in an additional productivity impairment. In April 1992, a retarded mud acid treatment performed in the well caused a severe productivity impairment. In November 1992, a revised retarded mud acid treatment with an improved clay stabilizer pumped into the well did not improve the productivity impairment.