Zhang X.-T.,Petrochina |
Zhang X.-T.,Sichuan Provincial Key Laboratory of Shale Gas Evaluation & Exploitation |
Chen M.,Petrochina |
Chen M.,Sichuan Provincial Key Laboratory of Shale Gas Evaluation & Exploitation |
And 6 more authors.
Natural Gas Geoscience | Year: 2016
Horizontal wells with multi-stage hydraulic fracturing are now the primary methods to achieve economic production rates in shale gas plays. The productivity of horizontal wells is closely related to geological factors and engineering qualities. Commonly used analysis methods of productivity characteristics for gas wells in conventional reservoirs were summarized and their adaptabilities to shale gas wells were discussed. The conventional methods could evaluate instantaneous productivity of a gas well but are not fully suitable for shale gas wells of which the productivity declines quickly in early days of production. Upon this fact, we proposed a novel analysis methodology for shale gas wells based on which the productivity during some time could be comprehensively evaluated. With the results of the new method, influencing factors of productivity were analyzed and the new methodology was applied to 14 production test wells in a domestic shale gas block to validate its practicability. © 2016, Science Press. All right reserved.
Kong L.-M.,Petrochina |
Kong L.-M.,Sichuan Provincial Key Laboratory of Shale Gas Evaluation & Exploitation |
Wan M.-X.,Petrochina |
Wan M.-X.,Sichuan Provincial Key Laboratory of Shale Gas Evaluation & Exploitation |
And 12 more authors.
Natural Gas Geoscience | Year: 2015
Based on a large number of thin section identification, scanning electron microscopy analysis, X-ray diffraction tests and some other experiments, the reservoir diagenesis of Silurian Longmaxi Formation in Sichuan Basin were studied. Seven diagenetic processes were identified, including compaction, cementation, clay mineral transformation, replacement, dissolution, organic matter thermal maturation and tectonic disruption. Three kinds of cements (quartz, carbonate and sulfide) were recognized, while the source material of quartz cements and the main factor of forming abandant carbonate cements were summed up. According to single well analysis of N3, it shows that the best, suboptimal and none shale reservoir sections were subjected to different diagenetic transformations. As to best shale reservoir, except for compaction, all the main inorganic diagenesis was significantly related to organic matter maturation. Through comprehensive analysis of diagentic indicators, it is indicated that the reservoir currently has already been in period B of middle diagenetic stage to late diagenetic stage. The inorganic diagenesis has a significant impact on shale reservoir, because it controls not only the conservation, development and evolution of porosity, but also the mechanical property and the adsorption capacity of rocks. However, the organic diagenesis is the source material of shale gas, and it generates a large number of nanoporosity in organic matter, which increase the total porosity and the adsorption capacity of the reservoir. ©, 2015, Science Press. All right reserved.