An Integrated and Reliable Workflow to Determine Critical Rates for Gas and Water Coning in Oil and Gas Reservoirs - A Multi Well Approach, Case Study Pemex, Mexico

Abstract

Commonly when fields are operated, there are several challenges to face and make profitable the operations, from the reservoir perspective one of the key challenges is when we have undesirable fluids that can cause cost in the operations and make more complex the production. This is the case when we have water or gas production in an oil reservoir or water production of a gas reservoir. First of all the productivity on the well can be affected, the recovery factor, and all the impact that can cause in the operations, costs, etc. When we talk about water production there are several possible sources associated to this problem, in the literature (Fig.1) there are at least ten know possible sources can cause water production, one of these problems considered is the coning phenomenon (Fig. 2). Eventually, the water or gas breaks through into the well and water from the aquifer and/or gas from the gas cap is produced along with oil. The water or gas production increases progressively after breakthrough time and may reduce significantly the crude oil production. Understand all the parameters that affect or influence coning is very important and also to be able to select the proper methods to analyze and mitigate it. In this paper the water or gas coning is examined covering some analytical methods and numerical reservoir simulation workflow applied to different reservoirs of the Veracruz Basin to understand the behavior of the wells, estimate the critical rates, the breakthrough time and establish a proper plan to this wells to avoid or mitigate the water and gas production; to reach this a numerical simulation workflow is proposed, examples and comparison is included when the wells are above or below critical rates.