Abstract
Sometimes we dive too quickly into the smallest of details when trying to plan for fracture stimulation applications in our industry. It has been too often that a frac design engineer will gloss over the importance of unknown or missing reservoir data but spend many hours chasing the "exact-best" value to use for the treating fluid viscosity in the frac design simulator. Some reservoirs we frac routinely and understand how fracturing is best applied, and a few where we can choose the full scientific approach and monitor with microseismic listening. When there is just no chance to know accurate reservoir data, we may have few design options. However, it seems more often the case that the "frac design world" simply does not search out important data available within the geologist-geophysicist realm. The available pseudo-3D and numerical 3D frac design simulator software available to us can be used as a crutch instead of a useful tool.
We can be a novice in frac design from our lack of experience, or because we do not understand how to use our experience in a new or different reservoir setting. In very recent years, we have witnessed many highly experienced "frac gurus" fail to understand how to apply their experience when moving to horizontal wellbore applications. This paper will offer guidance to the less experienced frac design personnel as to some of the more important basic concepts of integrating hydraulic fracturing applications to reservoirs or well completion plans where little experience currently exists. Some reservoirs have been evaluated and reported in our literature to near "overkill" proportions for vertical completions and then struggled to understand frac stimulation of horizontal completions. Within the large body of technical papers and texts, most have slighted the importance of two factors: Rock hardness and formation pore pressure of gas reservoirs. This paper will stress the importance of including these factors.
With record high oil prices, and in some markets, good gas prices, we are seeing the extension of hydraulic fracturing to areas and reservoirs where little or no "frac" experience exists. Additionally, our need to fracture stimulate when our wellbore is significantly deviated is starting to multiply in number and importance, both offshore and onshore. This paper will be a valuable aid to this transition.
