Real Time Evaluation On Physical Property Of Reservoirs And Its Fluids In Deep Layer Clastic Rocks Jiyang Depression

As technology advances, deep-seated oil and gas reservoirs have become the focus of exploration in the eastern part of our country, while this type of oil and gas reservoirs has features of complex reservoir, complex oil and gas bearing property and multiplied affecting factors. It has great difficulties for in time discovery and evaluation on oil and gas, and the interpretation coincidence rates for oil and gas zones are low. Conventional logging methods generally give qualitative estimation on reservoir and fluid but it is hard for them to give quantitative descriptions. Realizing fast and accurate evaluation on reservoir and fluid is an important subject of oil and gas exploration and development work. With the continual acceleration of exploration, there is an urgent need for logging to give real time evaluation on reservoirs fast and precisely on site, yet it is a blank both at home and abroad to have a comprehensive on site fast evaluation method with high academic standards and application values.Aiming at characteristics of deep layer reservoirs and fluids in Jiyang Depression, based on site logging data, we carried out analytical studies on wells with hole depth of greater than 3500m from different blocks. Firstly we carried out NMR logging method study. Using real time conventional logging data and NMR new logging technology to conduct fast identification and evaluation on deep layer reservoirs, we carried out deep researches on true and false oil and gas shows and influencing factors; under the basis of calibration and treatment, we carried out deep layer fluid evaluation to form deep layer clastic rock reservoir real time evaluation standards, methods and technologies.The main research topics are two aspects concerning real time identification and evaluation on reservoirs and fluidsFor real time identification and evaluation on reservoirs:under the basis of conventional logging for cuttings, cores and sidewall sampling, drilling time logging, carbonate content logging, and gas logging, we carried out NMR logging method studies and conducted plentiful basic experiments and field applications. It is discovered that there are three kinds of NMR relaxations in cutting samples:the surface relaxation, molecule self-diffusion relaxation and fluid relaxation, of which the surface relaxation has the closest relationship with physical properties of rocks. Single pore relaxation of cores/cuttings can be treated as single index relaxation; the total relaxation is the accumulation of these relaxations. Test duration and sample properties such as lithology, rock sample grain size, sample granularity, pore fluid property, wetting property, susceptibility as well as water salinity have significant influence on T2 spectrum. There is rich information in NMR T2 spectrum. According to the peak shape location of T2 spectrum of the saturated rock sample, amplitude height, shape of the peak, numbers of peaks, reservoirs can be fast identified and qualitatively evaluated. By direct measurement and calculation, parameters such as reservoir porosity, movable fluid and binding fluid saturation permeability and pore radius distribution can be got to realize quantitative evaluation on reservoirs.Studies on real time identification and evaluation for fluids are carried out from two aspects:(1) Fluid Identification:for oil and gas zone identification, we mainly conduct studies on various logging data to get response characters of hydrocarbon zones on logging data. According to features of gas logging methane relative percentage, tank top gas light and heavy hydrocarbon relationship and number of components, thermal evaporation hydrocarbon chromatograph component completeness, main peak carbon location and spectrum shape etc., it is possible to identify oil and gas zones. Gas logging equivalence ratio is another major method for oil and gas identification. For water-bearing identification, it is mainly through comparison of NMR logging fresh sample T2 spectrum and soak sample T2 spectrum to identify whether the formation is water-bearing. On the chromatograph elution curve'of thermal evaporation hydrocarbon chromatograph logging, undistributed substance is increased, the baseline rise up and the heavy components increase; in inlet and outlet conductivity logging, features of reservoir water content can be got. (2) Fluid evaluation is mainly conducted for carrying out studies on crude oil property, pay zone type and productive capacity. Many methods such as gas logging methane relatively percentage, quantitative fluorescent index for oiliness, rock thermal decomposition light and heavy hydrocarbon ratio exponent, and tank top gas component empirical formula can be used for crude oil density evaluation, of which quantitative fluorescent index for oiliness is the most simple, the most reliable and the most widely used one.Through studies on this subject, we (1) established a real time reservoir evaluation method based on logging new technologies such as NMR, etc., presented the new computing formula for permeability and computing formula of pore structure parameters, realizing fast quantitative evaluation on reservoir pore structures. (2) Established logging data treatment process and method, integrating a variety of methods such as thermal evaporation hydrocarbon chromatograph spectrum, comprehensive logging equipment inlet and outlet conductivity, NMR fresh sample and soak sample correlation spectrum etc to realize formation water bearing real time identification and evaluation. (3) established deep-seated clastic rock reservoir fluid real time evaluation method and technology series.