二個井壓測試點估算地層參數之研究

Estimating Formation Parameters from Two-Point Flow Test Data

林再興(Zsay-Shing Lin)

《鑛冶：中國鑛冶工程學會會刊》 32卷3期 (1988/09) Pp. 44-51

https://doi.org/10.30069/MM.198809_32(3).0004

摘要

利用單一井壓測試資料點估算油氣層滲透率的最大缺點是假設井眼之膚表因子為已知，為了避免該項假設之缺失，本研究之目的是探討如何使用最少之井壓測試資料點，在不必假設已知膚表因子之條件下，同時計算地層滲透率及膚表因子。本研究結果顯示，在一個油氣層或地層的某一口井襄，若有二個井壓測試點，不僅可以求出滲透率，而且，膚表因子也可算出，這個方法稱為二點法（或二點井壓分析法），本法所根據之基本理論（或基本方程式）與一般井壓測試作圖法所使用之基本方程式相同。依此，而導出計算滲透率及膚表因子之計算方程式。在證實該法之可用性及正確性時，首先，是利用該法分析電腦模擬程式所得之壓力資料，分析結果與模擬程式所輸入之參數（滲透率及膚表因子）相同。然後，又利用二點法去分析實驗室裏油氣層模型所得之井壓測試資料，所得之結果與實驗室所量度之結果以及與井壓測試分析所得之值，均相當符合。最後，將該法應用於分析臺灣某一口井之測試資料，所得之結果也與半對數作圖法所得之結果相同。所以，若測試資料之準確度可靠，而井壓測試資料點有限時，或是要快速求地層參數時，可以利用本文所導出的方程式計算滲透率及膚表因子。

並列摘要

A drawback of estimating formation permeability from single-point flow test shown in the literature is an assumption of knowing skin factor of the wellbore. In order to avoid the unreasonable assumption, the purpose of this study is to estimate the reservoir parameters, such as permeability and skin fator, using the least flow data points of two. The result of this study shows that the permeability and the skin factor can be obtained from two-point flow data for either constant flow rate or two-flow rate case. Pressure buildup is a special case of two-flow rate test. Pressure analysis using two flow data points is called two-point method. The equations used in the method are derived based on an analytical solution of the diffusivity equation which is the same as it used in conventional pressure transient analysis. The method is verified by analyzing the flow test data generated from a reservoir simulator in which the formation parameters are given and known. Also, a test run is made to analyze the flow test data taken from a physical model made in laboratory. The parameters (permeability and skin factor) obtained from two-point method are the same as the parameters known or measured. In addition, the method has been used to analyze data taken from a well drilled in Taiwan. A reliable result is observed by comparing the permeability and skin factor from the conventional pressure analysis and type curve matching technique and from two-point method.