Optimization of Hydraulic Fracturing in a Deep, Multilayered, Gas-Condensate Reservoir (SPE 63109)

Summary

In the deep gas condensate Barik field in Oman, many wells are capable of producing 15 MMCFD unstimulated.  Initial fracture treatments with 20/40 ISP resulted in 370% production improvements, while TSO designs with 12/18 HSP tail-in treatments resulted in 7-fold increases.

Abstract

Two deep, gas condensate reservoirs are under development in Oman to supply a peak capacity of 40 million m3/d gas for Liquefied Natural Gas (LNG) export and domestic customers. To date (May 2000) 37 multiply-fractured development wells, with a total of 106 hydraulic fracture treatments have been completed in the multi-layered, heterogeneous Barik and Saih Rawl fields.

A continuous optimization process was in place from the beginning to capture all aspects of the project's learning and reduce development cost. The frac design changes over time as a result of this process will be discussed. Initial well capacity of the wells cleaned up and tested to date is 20% higher than planned, offering considerable project savings.

This paper will describe the way in which the significant challenges in fracturing these deep, multi-layered gas-condensate reservoirs were met.

Difficulties in interpreting and analyzing FETs (Fluid Efficiency Tests) caused by varying stress contrasts in the different layers will be discussed. It will be shown that masking early data of the pressure decline after shutdown in the minifrac can result in misinterpretation of leakoff parameters. Well tests performed at regular intervals gave a better understanding of the optimized relationship between length, width, and height, which in turn led to a revised fracturing design. Perforating strategies influencing the placement of individual fracturing treatments, in particular affecting fracture connected height, will be addressed. Modeling reservoir characteristic has presented significant hurdles with existing fracture simulators, primarily caused by the amount of detail required to accurately predict both the fracturing and productivity behavior in the heterogeneous Barik and Saih Rawl fields.

Author(s): Halliburton Energy Services, R.A. Langedijk, S. Al-Naabi, H. Al-Lawati, Petroleum Development; R. Pongratz, M.P. Elia, T. Abdulrab

Paper Number: SPE 63109

URL: https://www.onepetro.org/conference-paper/SPE-63109-MS

 

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