Abstract

The main objective of this paper is to present a case history of 26 successful Multi-Stage Fracturing jobs performed in 4 horizontal (up-dip) wells drilled in the western onshore field of India. A detailed analysis of Frac job design, Stress profile analysis, well placement, exploitation approaches and successful implementation of new completion technology is also addressed.

Detailed stress profile studies were conducted to finalize the azimuth of the well. Placing the lateral section of the well with reference to the stress directions plays a major role in the success and effectiveness of fracturing in enhancing and sustaining productivity. Rock mechanical data was taken from nearby offset wells. The data was extrapolated over a lateral length of ~1000m and an up-dip angle up to 9 degrees. Considering the heterogeneity of formation, Mini-frac and DFIT test analysis were conducted in alternate stages to get the variance in leak-off and permeability throughout the horizontal section of the reservoir.

An exhaustive study involving numerous tests on core and oil samples were conducted including elemental analysis, XRD, SEM, Capillary Suction Time (CST), Non-emulsification tests etc. Observations from the tests confirmed that Pour point of the crude was considerably high and crude was waxy in nature. Mineralogical analysis showed more than 40% of MLIS clays. The inputs from these test results were incorporated in formulating the frac fluid as well as job design. Geoscience studies results were utilized in finalizing the well trajectory and placement. Sensitivity analysis helped in deciding the optimum proppant volume for the stages. Post frac job analysis confirmed achievement of target transverse frac geometry and good conductivity. The same results were also supported by the encouraging production performance from the wells.

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