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Research On Natural Gas Enrichment Rule Of The Weathering Crust Karst Reservoir Of Lower Palaeozoic Erathem In Western Area Of Jingbian Gas Field

Posted on:2014-05-30Degree:DoctorType:Dissertation
Country:ChinaCandidate:Q GuoFull Text:PDF
GTID:1220330431482307Subject:Oil and Gas Field Exploration and Development
Abstract/Summary:PDF Full Text Request
This article discusses the natural gas enrichment rule and the reservoir property of Ma5member in western area of Jingbian gas field. Based on the carbonate formation mechanism in lower palaeozoic erathem, the study combined multiple subjects including sedimentary petrology, logging, structural geology, geo-statistics, petroleum geology, seismic sedimentology and seismo-geology. Meanwhile several techniques are also applied, for instance, SEM, logging interpretation, seismic inversion, hydrocarbon detection and seismic facies analysis. The research achievements can greatly push the study area’s exploration and development process.(1) Ordovician Ma5formation suffered westward erosion, but basically speaking, it yields a relatively stable depositional thickness. Gas distribution and accumulation are mainly controlled by the sedimentary structure and ancient landform. Especially, Nose-like structure, which is developed in multi-lines, has a big effect on reservoir distribution. And erosion groove plays a significant role in gas accumulation, for its use in communicating with source, lateral sealing and reservoir stimulation.(2) The most important micro facies developed in the study area is dolomitic flat and is followed by the gypsum-dolomitic flat. Palaeokarst depositional environment and complicated diagenesis created a special set of pore configuration which is dominated by dissolved pore, cave and fracture and associated with certain intercrystal micropore and gypsum-die hole. These structures constructed the reservoir with a high permeable and accumulative pore type of fracture-solution pore as well as a fracture-micropore type with general seepage and storage capacity. However the configuration relationship, both vertically and laterally, between erosion groove and micro-fracture determines the migration, concentration and accumulation of the natural gas.(3) The development of fracture can greatly affect the heterogeneity degree of a reservoir for frac could communicate pore spaces and so improve the permeability. When well-developed fractures get connected with pore compact district, hydrocarbon enrichment can be expected.(4) Feasibility analysis and overall evaluation towards2D-seismic data indicate that its resolution ratio and signal to noise ratio is sufficient to restore the karst palaeogeomorphology and predict reservoir content and its distribution. Given the study area descends from west to east and is controlled by the karst palaeogeomorphology before carboniferous period, which is well developed with platform, monadnock, groove and shallow pit, gas accumulation is stable and mainly distributes around the raised ancient landform units which are split by grooves. In conclusion, among the study area, these groove and highland concentrated blocks in lower palaeozoic erathem is the favorable area for exploration and development.
Keywords/Search Tags:Ordos basin, western area of Jingbian gas field, carbonate rock, gas enrichment, reservoir evaluation, seismic prediction
PDF Full Text Request
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