Steam Stimulation History Match Of Multi-Well Pattern In The S1-B Zone, Cat Canyon Field
Authors: Herrera J.Q. , Hanzlik E.J. 
Published: December 2007

The high viscosity and low gravity characteristics of the crude oil produced from the S1-B zone in the Cat Canyon Field make it almost impossible to produce by other than thermal recovery methods. Getty Oil Company is presently producing this crude using the steam presently producing this crude using the steam stimulation process. However, based on field experience and computer studies, only 15% of the original oil in place will be recovered by steam displacement, on the other hand, is estimated to be as high as 40–45%. Before expanding into a steam displacement program, additional thermal model studies were required to gain a thorough knowledge of the S1-B zone.

The study reported in this paper consisted of first history matching the water and oil produced from five steam stimulation cycles of a produced from five steam stimulation cycles of a well which was considered to be typical of the greater portion of the field. This portion of the study was conducted using a three dimensional thermal simulator in a radial grid configuration. With only minor modifications, the data obtained was then used with the model in a rectangular grid mode to history match the water and oil produced from three wells. The findings of the produced from three wells. The findings of the study and the problems associated with history matching a group of wells simultaneously on production are discussed in this paper.

Introduction

For the past 5 years Getty Oil Company has been utilizing a three dimensional thermal simulator to study the S1-B zone of the Cat Canyon Field. Oil and water produced from individual steam stimulation wells in the field have been history matched in the past, but never the production from a group of wells simultaneously on production. In our study, we first history matched five cycles of a steam stimulation well. This refined the raw data obtained from logs, core analysis, sidewall samples, and published literature. The well was chosen because of its central geographic location within the reservoir. Its reservoir characteristics are considered to be typical of the greater portion of the field and it is equidistant from a portion of the field and it is equidistant from a past steam displacement pilot, a presently active past steam displacement pilot, a presently active steam displacement pilot, and a steam displacement pilot modifications, the resulting data was used pilot modifications, the resulting data was used to successfully history match three steam stimulation wells simultaneously on production. The modeled area consisted of an 11.25 acre (45,527 m2) semi-confined grid pattern.

MODEL DESCRIPTION

The model used in the study is described by Coats et al. Its computations account for viscous, gravity, and capillary forces and their effect on the three-phase flow water, oil and steam-hydrocarbon gas mixture. Also taken into account are the transport of heat by conduction and convection within a heterogenous one, two, or three dimensional reservoir, heat loss by conduction to the overlying and underlying strata, and the effects of three phase relative permeability. The oil can be treated as a permeability. The oil can be treated as a three-component mixture consisting of solution gas, volatile components. Vaporization and condensation of the volatile components depend on local temperatures and pressures. This model has proven to be a viable engineering tool for proven to be a viable engineering tool for making rapid comparisons of alternate operating procedures and detailed predictions of future procedures and detailed predictions of future performance.

GWP 48-24 FIVE CYCLE HISTORY MATCH

GWP 48-24 was completed and placed on production December 9, 1968. A historymatch, which production December 9, 1968. A history match, which included its pre-steam stimulation production and five steam stimulation cycles, was performed. The history match was carried out using the noncompositional radial option of the numerical model. This option assumes that no free hydrocarbon gas exists in the reservoir and that no distillation occurs.