| Based on the predecessors’ research results and the exploration data, Use the many kinds of technical means for mercury injection, relative permeability, water flooding, sensitivity, X-ray diffraction, the thin sections, image analysis, particle size analysis, cathode luminescence,scanning electron microscope and so on, this thesis wholly analyzed and deep studied the pore structure of chang7reservior of L89well area in Xifeng Oilfield. Analyzed ultra-low permeability reservoir pore structure and seepage characteristics and discussed effects of diagenesis for the pore structure and seepage characteristics. Achieved the following results and understanding:1. Chang7reservoir diagenesis is relatively strong, Destructive diagenesis are primarily compaction, pressure-solution and metasomatism. The constructive diagenesis are primarily dissolution, fracturing. The diagenesis and evolutionary phase has been achieved B period. Summarized the chang7reservoir diagenetic sequence and pore evolution characteristics, the diagenesis is the key to affect chang7reservoir performance.2. Chang7reservoir microscopic structure is complex, The pore types include intergranular dissolved pore, intragranular dissolve pore and Other trace. High and steep mercury injection curve platform,high displacement pressure,high median capillary pressure, low efficiency of mercury withdrawal, Micro throat.Pore space is mainly composed of pore throat less than0.3um (radius) Permeability is mainly composed of micro-fine throat between0.1～0.3um (radius). The average median throat radius is0.0914um. Refer to the predecessors research results,establish classification criteria of pore throat structure for chang7reservoir.3. Sedimentary facies, clastic and cement type and content, diagenesis, microstructure and micro cracks are the main factors affecting reservoir physical properties. The pore and permeability and pore throat structure parameters are closely related. |
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