With increasing demand for natural gas, higher product prices and the availability of improved extraction technologies, there is increasing focus on infill drilling in tight gas reservoirs. However, quantification of incremental recovery (one of the key value generators) is often challenging particularly in commingled multi-layered heterogeneous fluvial reservoirs with a paucity of data collection. The issues related to the volume and quality of data collected are magnified when low cost infill development is undertaken. This paper demonstrates a new technique using production data (in isolation) to estimate incremental and accelerated recovery for such a development.
For infill development, various methods have been proposed to quantify incremental recovery. The most common range from simple reservoir continuity models, Arps Decline Curves, Material Balance, field analogue studies, to complex reservoir simulation. This paper discusses a new methodology termed ‘Progressive Multi-well Blasingame Analysis’ based on Blasingame type curves which successively compares boundary-dominated responses from each infill phase to distinguish incremental from accelerated recovery achieved from each phase of infill development.
The paper reviews the theoretical support for the Progressive Multi-well Blasingame Analysis method via a numerical simulation study. Demonstration of this methodology is performed using a field case study to quantify incremental recovery and identify additional infill opportunities in an environment where limited reservoir surveillance was conducted. The paper concludes by discussing the applicability and the pros and cons of this technique.
In essence, this paper addresses an existing knowledge gap in industry as it provides a method to efficiently evaluate a group of wells and distinguish incremental from accelerated recovery using only the production rate and flowing tubing head pressure data.