Study On Fractures Log Response Base On Microresistivity Scanning Imaging Logging And Carbonate Reservoirs Fluid Automatical Identification

During exploration of oil and gas in the world extent enhance, most hydrocarbon reservoirs that easy to find have been explored. Other reservoirs that hasn't found are more and more complexity in reservoir physics property and conformation. It became difficult to explore and evaluates these reservoirs, for exploiture difficulty and cost increasing. Conventional loggings can't precise and efficient identify fractures, especially about figure and distribute density of fractures. Imaging logging can provide high resolution well hole images and identify fractures particularly. For electrical imaging logging is the newest logging method in the petroleum loggings, it can interpret many geological characters by making use of electrical imaging's pictures. By geological character becomes more complex and imaging logging be required to making quantitive interpretation, it became more and more difficult. So we must analyst the response of microresistivity imaging logging in vary geological characters. It is precondition in applying the imaging logging data to interpret geological characters. We can do well in interpreting imaging loggings image and in effectively quantitive interpreting the imaging logging data by using this precondition. Carbonate hydrocarbon reservoir is a important style reservoir. In my country Szechwan, the Tarim Basin possess of many hydrocarbon reservoirs that contains in the carbonate reservoirs. Because of deposition, diagenesis, conformation and carst effect, Carbonate reservoirs always develop fractures, vugs, caves and so on. Reservoirs have low matrix porosity, anisotropy features, it make evaluating reservoir and identifying fluid become more difficult. Electrical property is the most difference parameter in the oil-water physical response parameters. But for carbonate reservoirs, resistivity information is the synthetize of reservoir lithology, physical property, fracture and vuggy styles, fluid types, anisotropy, dolomite and so on; all these make ambiguity, uncertainty in fluid identification. Ariche saturation equation built base on uniformity sand reservoir model is not adapt to evaluating fluid property in carbonate reservoirs. For cave reservoirs, we couldn't identify fluid property because of mud filter invade in formation serious. Improving acquaintanceship of carbonate reservoir, mastering reservoirs property and presenting methods of fluid identify are important problems. Resolve these problems will save production cost and enhance reserves of country backup oil-gas reserves and production. It is a important process to simulate response of resistivity imaging loggings. We acquire some significative conclusion after we have processed primary explore. In research course we build up appropriate partial differential equation, proper three-dimensional model aim at face problems. We build up two geological models such as uniformity, plane fracture formation. And we chose two width factures to calculate. Use these model we decide investigation depth and radial range of imaging logging. Fluid identification is very difficult because of carbonate reservoirs structure complexity. In order to solve this problem, we synthesis geological character and oil, water logging response, think about four methods using conventional logging data to identify fluid. These four methods contain GR-RD cross plot, normal distribution P1/2, indirect identify, dual porosity overlap disveal oil. We use these methods in research region to confirm effect and applied domain. GR-RD cross plot method is adapt to each type reservoirs, and gain good effect. We have calculated eighteen wells using normal distribution P1/2. The result reveal that it has better effect in fracture reservoirs and fracture-vuggy reservoirs, but is not adapt to shaly formation and cave reservoirs. Dual porosity overlap reveal hydrocarbon method is adapted to identifying water reservoir but not adapt to identify oil reservoir in fracture and fracture-vuggy reservoirs. And this method has not any effect in cave reservoirs. Indirect identify method is adapt to cave and fracture reservoirs, but not adapt to vuggy reservoirs. According applied effect about these identification methods on carbonate hydrocarbon reservoirs, we pick up three indexes from normal distribution P1/2 method, dual porosity overlap method and GR-RD cross plot method as fluid identification indexes. And add other four indexes that reflect fluid property, six indexes that reflect stratum preserved ability, totally thirteen indexes. These indexes divided into two levels, one level is to preserve ability, and second one is the fluid property. On the basis of confirming the preservation of strata, we identify the fluidproperty of this stratum. We choice different right coefficients according to vary regions and type of preserving. And have built up automatic calculation to this method. Using multi-parameters synthetical identification method, we have research about fifty test horizons for part typically water wells, developing wells, and explore wells totally thirty-five in Ta'he oil field. There are twenty-six fracture reservoirs, seventeen vuggy, little cave reservoirs and eight cave reservoirs in these wells. We have correctly deal with and interpret forty horizons, and there are twelve water horizons, sixteen oil horizons, five oil weak horizons and three oil-water horizons in these. Correct rate of interpretation is 71%. This research approach has obtained some achievement, but the correct rate must be rise step forward. We need more test information about vary types reservoirs to regulating right coefficients, in order to apply to different situations.