East Leman Unit Water Influx Investigation

This paper was prepared for the Second Annual European Meeting of the Society of Petroleum Engineers of AIME, to be held in London, England, April 2–3, 1973. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract A two dimensional, two phase vertical reservoir model was used to simulate bottom water influx into the East Leman Unit. The influence of well cluster drainage, well drainage area, aquifer extent, permeability level, horizontal-vertical permeability ratio, aquifer-gas zone permeability ratio, and production after breakthrough were production after breakthrough were investigated. The results indicate that water influx will not be a significant factor in future performance primarily because of extremely low water mobility associated with the reservoir rock. Introduction The Leman Field is a large dry gas reservoir located approximately 30 miles off the East Anglian coast. It was discovered in 1966 and produces from the Rotliegendes sandstone, an aeolian deposit of Permian age, the gas being trapped in a northwest-southeast elongated dome approximately eighteen miles long by eight miles wide. The top-of the producing formation varies from 5,900 to 6,750 feet subsea within the field area providing a gross pay thickness at the crest of the structure of up to 850 feet. The Leman Field reservoir is underlain by bottom water almost everywhere, and the influence on both well and field performance requires evaluation. performance requires evaluation. Furthermore, the importance of the field, its location offshore, and the essential fulfillment of contract requirements necessitates accurate long range development planning. To achieve this objective for the heterogeneous reservoir rock reservoir simulation for performance prediction is highly desirable. performance prediction is highly desirable. A two phase, three dimensional simulation model would permit the best evaluation of aquifer influence. However these models require elaborate data input and are time-consuming and difficult to set up.