Focusing Stimulation Efforts on Sweet Spots in Shale Reservoirs for Enhanced Productivity

Abueita, Samir²; Tonner, David⁴; Barnett, Craig³; Hashmy, Khaled H.⁵; HASHMY, Khaled H.¹
¹Geoscience, Weatherford International, Houston, TX.
²Petrophysics, Anadarko Petroleum, The Woodlands, TX.
³Drilling Services, Weatherford International, Houston, TX.
⁴Weatherford Laboratories, Weatherford International, Houston, TX.
⁵Geosciencs, Weatherford International, Calgary, AB, Canada.

As the quest for shale oil and gas spreads to South America, Europe, Asia and Australia, inevitably the operating practices of North America tend to serve as the template for the new, frontier areas. With either a sparse evaluation from logs, cores and cuttings or none at all, the ubiquitous approach for selection of zones for hydraulic fracturing in the long laterals in North America is to place 20 to 30 frac stages, more or less evenly spaced along the lateral, often without regard to variations in the reservoir properties. In many cases, especially in early stage frontier regions, a more comprehensive alternative approach that includes geological data integration to selectively optimize completion and stimulation intervals could be advantageous. Specific field examples presented here show how each of the following can serve, in varying degrees, to delineate zones with better reservoir properties from those with poor reservoir characteristics (i) near real time measurements of XRF, XRD and pyrolisis on cuttings at the well site (ii) a superior approach to monitoring the real-time hydrocarbon (C1 - C8, benzene, toluene) and non-hydrocarbon gases (CO2, N2) dissolved in the drilling fluid in the mud stream (iii) LWD spectral gamma ray and density measurements (iv) LWD Shock wave acoustics and (v) suites of openhole well logs obtained in horizontal shale gas wells This enables the operator to concentrate frac dollars in zones that are more productive and at the same time, avoid intervals that are not likely to be good producers. A relatively small investment in such surveys to delineate sweet spots could yield major dividends in enhanced productivity and improved utilization of frac dollars.

AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012