A case study of excessive water production diagnosis at Gialo E-59 Oil field in Libya

Abstract

The main problem with Libyan oil fields is the excessive production of water. The purpose of this paper is to diagnose excessive water production mechanisms. Chan approach, PIPESIM Software, and Vogel Equation were applied to the oil well (E-226) at the Gialo E-59 field in Libya. Considering an example of data from a Libyan oil well, the derivative method of the diagnostic charts is applied using Microsoft Excel format to calculate and plot the derivative response to understand the mechanisms causing the problem. As a result of this research, channeling is the main reason for water production, and normal with high water cuts is the other phenomenon for wells. Based on systematic numerical simulation studies of reservoir water coning and channeling, it was discovered that log-log plots of WOR (water/oil ratio) versus time show different characteristic trends for different mechanisms. The time derivatives of WOR have been found to be able to discriminate whether the well is experiencing water coning, high permeability, layer breakthrough, or channeling near the well. The technique of Chan (1995) was applied to well E-226 in Waha oil company s Gialo E-59 field in Libya. Similar to the results obtained by Chan (1995), it can be seen from our results that WOR plots for coning and channeling mechanisms can exhibit similar behavior. Also, this is no surface choke installed in this well, and a full open choke size can cause a variety of undesirable problems such as water/gas breakthrough, sand production, and erosion.