| Marine carbonate reservoirs, the most important areas of global oil and gas exploration continue to make breakthroughs, wherein Tabei uplift Ordovician carbonate reservoir is buried by the tectonic movement and weathering crust karst common the role of the joint formed to construct a large crack and cave as the main controlling factor fractured-vuggy Reservoirs. Located north round south tower hill site Lungu Block15oilfield Ordovician reservoir, is this karst cave as the main reservoir space, cracks as a seepage channel, dissolution cavities and construction corrosion cracks for the secondary storage space permeability, low porosity and permeability of the matrix rock barrier special type of carbonate reservoirs. On the basis of carbonate fracture Lungu Block15collective holes reservoir parameters to identify and analyze the characteristics of the Ordovician, combining core, slice, logging, seismic data vuggy collective reservoir fine description and characteristics of fractured type reservoir control factors related to analysis and discussion, and seismic data for reservoir collective fractured horizontal distribution were predicted. The main outcome of the following understanding.(1) Carbonate reservoir in Yingshan formation of Lower-Middle Ordovician in block NO.15of Lungu oilfield is a large fractured-vuggy system formed by weathering crust karst.The reservoir pore space of Lungu Block15mainly consisted of touching-vugs such as fractures related with karst cavities and pores.From the core, conventional logging, logging, drill logging, seismic and other aspects of caves, voids, cracks and other reservoir space comprehensively identified. Cave showed patchy FMI imaging logging, logging and drilling vent leakage chaotic seismic reflection characteristics, the filler can be colluvial, chemical precipitation and mechanical deposition components. Pore usually densely punctate on on FMI. Cracks in construction joints, corroded fissure and into the crevices of the points, a single well surface seam rate0.28%-2.03%, with an average of0.85%.(2) Study area Yingshan formation matrix porosity of1.23%on average, with an average permeability of0.23×10-3μm2, is a low porosity and permeability characteristics, contributed greatly to the cave and fracture reservoir and hydrocarbon output. According to the reservoirs and filling characteristics proposed reservoir facies, and the division of the weathering crust sediments draping phase, weathering crust karst cave phase, phase epikarst holes, cracks epikarst phase and dense phase five reservoirs phase of weathering crust karst and14subfacies reservoirs and22sub-phase reservoir microfacies.(3) Sub-cave, fractured hole, fractured vertical body-type on the reservoir development characteristics were analyzed. Developed fractures in the transverse direction within the range of less than100m away from the top of the weathering crust, reservoir development was two-three, good lateral continuity. Down reservoir thickness smaller, continuity deteriorated.100m the following reservoirs mostly punctate distribution.(4) Weathering crust karst landforms and different critical reservoir under development. According weathering crust karst area, monadnock magnitude monadnock aspect ratio, single well hole seam characteristics were divided all types monadnock252. With the effect of cracks centralized development and control of erosion and karst cave hole with the development and distribution, Lungu Block15wells are located in the most densely Interchange multiple fractures and in the Yingshan formation drilled cave development zone, its single well hole drilling rate of92.11%.(5) On a plane, fractured reservoir high values in the vicinity of903Lungu,15-8and Lungu15-21wells; fractured reservoirs along the rupture rate of drilling high value, Lungu15-11,15-4and Lungu15-20developed most; cavity reservoir as a whole is not high. The study area favorable reservoir mainly in karst monadnock and with faults, fractures superimposed development area. |
PDF Full Text Request