Abstract

This paper discusses the effect of production rates on lateral water migration in the gas producing strata of the Jumping Pound West Gas Field. The study was performed using a multiphase, multi-dimensional mathematical reservoir simulator as a two-phase, two-dimensional cross sectional model.

The results of the study indicated that there would be no detrimental effects on production performance and on total field ultimate recovery by producing the gas wells at maximum deliverability. Since the two-dimensional cross sectional models showed that water did not encroach towards the well bore, additional more elaborate simulation, as a second step of investigation, was not warranted.

Introduction

The purpose of this paper is to demonstrate the use of a multi-phase, multi-dimensional mathematical reservoir simulator to investigate water encroachment in the Jumping Pound West Field. Water encroachment is the lateral migration of formation water developing after certain equilibrium conditions are imbalanced by increasing the pressure gradients over a producing section. It is very important to be able to evaluate this phenomena and ascertain ways of controlling or eliminating its adverse effects.

The Jumping Pound West Field is located 28 miles west of the city of Calgary, Alberta, in the eastern foothills of the Rocky Mountains, Figure 1. This field was discovered in 1961 with the drilling of Shell JP West 11-5-26-6 W5M, encountering sour wet gas in Mississippian Turner Valley formation at a depth of 9,646 feet. The natural gas produced from this field is used on the Alberta domestic gas market which is subject to large seasonal demand variations. As a result a high level of deliver ability must be maintained to meet short winter peak demand periods. Because of the large capital expenditures necessary to maintain this capacity it is desirable to be able to produce all wells at maximum deliverability to meet the contract requirements. The only detrimental effect of concern with high producing rates could arise from lateral water encroachment since formation sloughing and sanding are not problems due to the competent nature of the producing formation in this field.

STUDY OUTUNE

A structural geology study of the Jumping Pound West Field indicated that conventional water coning calculations were not applicable because, in no case J are the wells completed in a zone directly above a gas-water contact in the same thrust element. Therefore, only water migration from a gas-water contact down flank from the wellbore was considered as a possible source of adverse water production.

Two-dimensional cross sectional models were constructed to s1mulate fluid flow in three cross sections through the following wells which are situated closest to water in the field:

  1. Shell CPOG Unit Jump W 11-36-24-6 W5M

  2. Shell 4 Jump W 2-33-25-6 W5M

  3. Shell 7 Unit Jump W 2-14-25-6 W5M

The cross sectional models were designed to study water migration distant from the wellbore. If severe water migration was observed to be moving towards the wellbore then a more detailed simulation would be necessary as a second step of investigation.

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