气驱–水驱联合特征曲线在气顶边水油藏中的应用

气顶边水油藏进入开发中晚期后,面临着气窜与水侵的双重难题,需要评价开发效果,并基于评价结果调整开发策略,但无法直接应用气驱特征曲线或水驱特征曲线评价该类油藏的开发效果.因此,基于稳定渗流理论,推导了气驱特征曲线关系式,并与水驱特征曲线关系式联立,建立了计算不同阶段气驱产油量占总产油量比例的方法;利用该方法可计算出气顶边...

Application of a Gas and Water Drive Combined Characteristic Curvein Reservoirs with Gas Cap and Edge Water

When reservoirs with gas cap and edge water enter the middle and late stages of development, challenges of gas channeling and water cut emerge, and relevant evaluations and development strategy adjustments are needed depending on evaluation results. However, the development effect of such reservoir cannot be directly evaluated by the characteristic curve of gas drive or water drive. In light of this, this paper presents a method for calculating the proportion of oil production by gas drive at different stages by combining the relations for characteristic curves of water drive and gas dive. Specifically, the relation for characteristic curve of gas dive was derived based on the steady seepage theory. The degrees of reserve recovery by gas drive and water drive in reservoirs with gas cap and edge water can be calculated using this method, and the calculation results can provide a basis for adjusting the development strategy. The calculated degree of reserve recovery by gas drive was 24.3% for the upper part of an oil group with gas cap and edge water in Well Block 3 of JZ-X Oilfield, and that by water drive was 48.4% for the lower part. Considering that the degree of reserve recovery by gas drive in the upper part was low, barrier water injection was intended to be conducted for enhancing the oil recovery of the oil group. The research indicates that the development effect of reservoirs with gas cap and edge water can be evaluated by the gas and water drive combined characteristic curve.