Interpretation Research Of Early Welltest Data

This paper aimed at the early information of low permeability reservoir that well testing pressure buildup slowly, pressure response affected by wellbore storage remarkably, then developed the interpretation method researches of afterflow rate convolution and deconvolution. Laplace numerical transform and Laplace space deconvolution method are utilized to developed direct deconvolution mathematics method which contains wellbore storage and changeful wellbore storage effect and avoid testing afterflow rate to extend the scope of application of deconvolution. Bring forward the deconvolution approach of integrate conventional interpretation method, via the analysis of conventional log-log to make certain the wellbore storage coefficient, father go on the deconvolution calculation, so exhibit semi-log radial flow characteristic, and also reduce the multi-solution in early data; in terms of the principle: "solving in process, achieve the exactitude step by step", using the technique combined with conventional specialized straight line analysis and typical curve auto matching, so, formed a high-efficiency and accurate interpretation process; build up a practicability interpretation method for multi-phase flow. Utilized pseudo-pressure method to unify gas well and multi-phase problems; apply steady and rapid optimization algorithm of the typical curve auto-match; directly interpret early information with optimum approach. also, The early welltest software has been developed to adopt the manner that do inspection while the interpretation was carrying on, do match and compare among the different interpretation method, further reduce the multi-solution probability; according to the applying and inspection of pressure build-up practical information from 6 wells, proved the interpretation and evaluation result from this software system are reasonable and credible.