Minifract

PROCEEDINGS JOINT CONVENTION BALI 2007
The 32^nd HAGI, The 36^th IAGI, and The 29^th IATMI Annual Conference and Exhibition

Modifikasi Minifract Pada Kondisi Tortuosity di Sumur Dengan
Permasalahan Kerusakan Perforasi.

Hisar Limbong dan Sumadi Paryoto

Teknik Produksi-Reservoir / Engineering
PT.Pertamina EP Region Jawa

ABSTRACT

Minifract have been recognized and well used as the most accurate method to determine data in Fracturing design. Minifract is a pumping treatment with a non compressible fluid which is designed to be as closed as possible to the actual treatment (Mainfract), without using any proppant/sands.

However in the well with tortuosity problem, the application of minifract pumping will meet constraint because of increasingly surface pressure higher compared to the low pumping rate. Tortuosity is the creation of small fractures leading from perforations that may or may not fully connect to the main fracture during hydraulic fracture operations. Tortuosity can caused premature screen out, which is sand/proppant can’t be delivered successfully through well bore. And make the result of gain production less than expectation; in worst case it will make the well lost. Tortuosity phenomenon can be identified with step rate test method. At step rate down phase, which is part of step rate test, this phenomenon can be indicated by doing curve analyze by plotting data between pressure and pumping rate.

The purpose of this paper is to present a situation/case which is the phenomenon of tortuosity is not clearly identified, thus the application of minifract pumping wouldn’t reach as ideal pumping rate as is wanted because tortuosity create pressure drop between well bore and fracture zone. This distinctive case of unidentified tortuosity phenomenon caused by perforation damage of the well bore. The modification of minifract is done by pumping slug method to overcome tortuosity effect, so that pumping rate can achieve as high as its wish without any constraint of surface pressure.

Keywords : Minifract, Tortuosity, Step Rate Down, Pumping.