Font Size: a A A

Research On The Experimental Analysis And Application Of The Complex Reservoir Rock NMR

Posted on:2008-12-30Degree:MasterType:Thesis
Country:ChinaCandidate:Y LiFull Text:PDF
GTID:2120360245999717Subject:Earth Exploration and Information Technology
Abstract/Summary:PDF Full Text Request
Compared with other logging, NMR logging has the unique technical advantages in the sizes and the distribution of pore in reservoir and so on, and provides an effective method for determining the irreducible water saturation and permeability of reservoir more directly. Firstly, this paper is aimed to research low porosity and low permeability reservoir core, starts from processing NMR relaxation to study the multi-exponential inversion methods systematically. Secondly, based on the NMR experiment, NMR relaxation distribution can be acquired which rich formation information, and then be processed and analyzed. Explore determination method of NMR T2cutoff is a keystone in the paper. Finally, the high temperature and high pressure NMR experiment is carried out, in order to research the effect of temperature and pressure on the NMR transverse relaxation characteristic.The multi-index inversion of porous media NMR relaxation plays a key role in NMR core analysis and logging interpretation. So we can use multi-index inversion to extract effective signal and get reliable NMR relaxation distribution. Firstly, we construct relaxation time spectrum with the typical characteristic, set different pre-assigned number, echo number and SNR to relaxation time respectively, and then use the damping least square method to inverse the relaxation signal, finally analyze the effect of each factor on the inversion result in order to determine inversion conditions.The experimental analysis of core is the foundation of the quality control, processing and interpretation of data and geological application of NMR logging. In this paper, aimed to the low porosity and low permeability reservoir core, we set up acquisition parameters optimally, measure NMR relaxation time before and after centrifugation, and analyze their T2 distribution characteristic. And then we calculate NMR porosity and permeability, and compare with conventional porosity and permeability. Both of them are very correspondent. Further, this research achievement is applied in the oilfield, and effect is good.In the NMR logging, selection of T2cutoff is critical to obtain reservoir parameters. In the paper, according to the characteristic of T2 distribution before and after centrifugation, a new method is explored to determinate T2cutoff. Then based on the T2 distribution combined with mercury porosimeter conference, we use the linear and the nonlinear methods respectively to transform NMR relaxation distribution, compare the result and optimize the transformation method, and then research pore structure parameters quantitatively. Finally, because NMR T2g reflect pore structure, the relation is built between NMR T2g and cementation exponent m, saturation index n, in order to imply pore structure to optimize the model of saturation, and improve the precision of the saturation model in low porosity and permeability reservoir.Generally, experimental analysis and research on NMR is carried out in the condition of normal temperature and normal pressure, and research on NMR experiment is least in the high temperature and high pressure. In the paper, we choose free water, transformer oil, water-saturated core sample respectively, carry out NMR experiment with different temperature and pressure, and then analyze the effect of temperature and pressure on liquid and core NMR relaxation, which provide the beneficial reference for using the result of NMR experiment for the calibration of the result of NMR logging.
Keywords/Search Tags:Nuclear Magnetic Resonance, low porosity low permeability, multi-index inversion, pore structure, high temperature and high pressure
PDF Full Text Request
Related items