Identification and Characterization of High Permeability Zones Using Conventional Logging and Production Logging Data: A Case Study of Kela 2 Gas Field

Abstract

High permeability zones in the water-drive gas reservoir tend to act as dominant channels for formation water to invade into gas reservoir from the aquifer. The presence of high permeability zones results in uneven water flow front in reservoir and early water breakthrough in gas well, which seriously affects the gas field development. In this paper, conventional logging and production logging data are used to identify and characterize high permeability zones, so as to guide the optimization of development plan of Kela 2 gas field. A method to determine the lower limit of high permeability zones by using cumulative frequency curve of permeability distribution is proposed, and high permeability zones of 21 wells are identified. These high permeability zones account for 10–15% of the effective reservoir thickness in single wells, and they are mainly distributed in the middle of the Bashijiqike (K1bs) Formation (i.e., K1bs12, K1bs21 and K1bs22). The analysis of production logging data shows that the effective gas producing intervals only account for 29.2% of the total number of test intervals, most of which are related to high permeability zones. Further study shows that the high gas flow from the high permeability zones dominates the wellbore production profile, and the gas in low permeability zones flows vertically to the high permeability zones and horizontally to wellbore through these zones. Through the analysis of production profiles over the years and computer modelling, it is confirmed that water channelling occurred in some gas wells at the depth where the high permeability zones are located, which leads to a significant decline in production of these wells. Based on the study of distribution and behaviour characteristics of the high permeability zones, two suggestions on controlling inhomogeneous water invasion are put forward to realize the sustainable and stable production of the gas field.

Preparation of Low-Viscosity Epoxy Resin Sealing Agent and Evaluation of Injection, Plugging, and Degradation Properties

“…Due to a long period of water injection development, the high water production rate has hampered the development of the oil and gas industries in recent years. − The oil and gas reservoirs formed the high-permeability regions after the long-term injection of water, resulting in the lower mechanical energy utilization rate of the injected water and oil and gas production rate. , Moreover, other reasons that caused the high water production rate included cement sheath failure and channeling flow outside the horizontal well tube. − Globally, the annual water production rate of oil and gas reservoirs increased each year, which considerably restricted the stabilization and increase in oil field production. About 3–4 tons of water was produced per ton of oil produced, and old oil fields produced more water.…”

“… 1 − 3 The oil and gas reservoirs formed the high-permeability regions after the long-term injection of water, resulting in the lower mechanical energy utilization rate of the injected water and oil and gas production rate. 4 , 5 Moreover, other reasons that caused the high water production rate included cement sheath failure and channeling flow outside the horizontal well tube. 6 − 9 Globally, the annual water production rate of oil and gas reservoirs increased each year, which considerably restricted the stabilization and increase in oil field production.…”