Replacing all sand with RCS or ELWC generates $1 million profit per well, increasing IRR from 3% to 44%. If well logs allow accurate prediction of well potential, economic potential can be further optimized.
The Frontier formation located on the Moxa Arch in southwest Wyoming is a "tight" gas sand that has produced significant gas reserves. Over 700 wells have been drilled and completed in the area covered in this investigation. Hydraulic fracturing is the primary means of completion stimulation and treatments have varied in size and fluid type over the 20 years of development. Many treatment designs and results have been reported in the literature.
In designing hydraulic fracture treatments attempts are made to "optimize" the economic return through the use of reservoir and fracturing computer models. The design of the "optimized" treatment and the estimated economics depend on the estimation of many reservoir properties. The most important of these is the estimation of permeability. Most often an average permeability for an area of a field is used. This may lead to a general "optimized" design but not an individual, well specific design. It is only when we can design for specific well conditions that a truly "optimized" treatment design can be achieved.
In this paper we will present a reservoir description technique which has proven successful at predicting the in-situ formation permeability and allowed for intelligent decisions about completion design to be made. Detailed analysis of standard openhole well logs is used to provide this permeability estimation. The ability to predict production response in over 70 wells is the proof that this technique provides valuable information to make completion decisions. We will present the results of these analyses and the production results. We will also quantify the benefit or detriment of different completion designs used in the study area by comparing well response normalized for reservoir quality. The authors believe that the methodology used can be applied to similar reservoirs to achieve similar results.
Author(s): S.K. Schubarth, Halliburton Energy Services, and R.A. Chabaud, Union Gas Operating Co.
Paper Number: SPE 50609