科研之友
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摘要
The amount of tight-formation petrophysical work conducted at present in horizontal wells and the examples available in the literature are limited to only those wells that have complete data sets. This is very important. But the reality is that in the vast majority of horizontal wells, the data required for detailed analyses are quite scarce. Petrophysical evaluation in the absence of well logs and cores can now be considered owing to the possibility of measuring both the permeability and porosity of drill cuttings. This is essential because the application of the successive correlations used throughout the paper is based on porosity and permeability data. %26lt;br%26gt;To try to alleviate the data-scarcity problem, a new method is presented for complete petrophysical evaluation derived from information that can be extracted from drill cuttings in the absence of well logs. The cuttings data include porosity and permeability. The gamma ray and any other logs, if available, can help support the interpretation. However, the methodology is built strictly on data extracted from cuttings and can be used for horizontal, slanted, and vertical wells. The method is illustrated with the use of a tight gas formation in the Deep basin of the western Canada sedimentary basin (WCSB). However, it also has direct application in the case of liquids. %26lt;br%26gt;The method is shown to be a powerful petrophysical tool because it allows quantitative evaluation of water saturation, pore-throat aperture, capillary pressure, flow units, porosity (or cementation) exponent m, true-formation resistivity, and distance to a water table (if present). Also, the method allows one to distinguish the contributions from viscous and diffusion-like flow in tight gas formations. The method further allows the construction of Pickett plots without previous availability of well logs, and it assumes the existence of intervals at irreducible water saturation, which is the case of many tight formations currently under exploitation. %26lt;br%26gt;It is concluded that drill cuttings are a powerful direct source of information that allows complete and practical evaluation of tight reservoirs in which well logs are scarce. The uniqueness and practicality of this quantitative procedure originate from the fact that it starts only from the laboratory analysis of drill cuttings-something that has not been performed in the past.
- 出版日期2014-8
- 单位中国石油大学（北京）
