THE SPE IMAGE LIBRARY SPE 37104SPE 37104 Numerical Simulation of Infill Drilling With Horizontal and Vertical Wells: A Case Study of Partial Bottom Water Drive Reservoir Gokhan Coskuner, SPE, Scientific Software-Intercomp and Joseph Melon, SPE, The Wiser Oil Co. Canada Ltd.Copyright 1996, Society of Petroleum Engineers, Inc.This paper was prepared for presentation at the 1996 SPE International Conference on Horizontal Well Technology held in Calgary, Canada,18-20 November. This paper was selected for presentation by an SPE Program Committee following review of information contained in an abstract submitted by the author(s). Contents of the paper, as presented, have not been reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material, as presented, does not necessarily reflect any position of the Society of Petroleum Engineers, its officers, or members. Papers presented at the SPE meetings are subject to publication review by Editorial Committees of the Society of Petroleum Engineers. Permission to copy is restrictedto 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. Write Librarian, SPE, P.O.Box 833836, Richardson, Texas 75083-3836, U.S.A., fax 01-214-952-9435. Abstract The Provost Dina 'X' Pool is a turbidite sand with a pay zone of up to20 m at a depth of 200 mSS. The field contains approximately 1.2million m3 of oil and there is a bottom water aquifer with partial pressure support in parts of the field. Most of the vertical wells in the field shut-in due to high water cuts after a relatively short period of production. Therefore, a numerical simulation study of the whole field was undertaken in order to improve recovery by infill drilling as well as by investigating different operating strategies. This paper describes the integrated team approach taken with input from the geological, production and reservoir engineering specialists to construct a reservoir model. The model has been successfully history matched and used, in turn, for predicting the performance of the field under existing conditions as well as a variety of infill drilling and operating scenarios. Results indicate that significant water coning, which would be observed with new vertical wells in certain areas of the pool, can be reduced through horizontal infill wells. Despite the potential technical success of horizontal infill wells, they were not economically feasible in this particular reservoir and vertical infill wells were the preferred choice. It is shown that a combination of carefully planned vertical infill wells and a pressuremaintenance program is able to boost the ultimate recovery by 34% while keeping the development costs to a minimum. Results of various operating strategies are presented and the optimum field development

THE SPE IMAGE LIBRARY SPE 37104 scenario implemented in the field is outlined. The initial actual reservoir behaviour is discussed in the light of the results from the simulation study. IntroductionThe Provost Dina 'X' pool was discovered in 1988 at an initialpressure of 6450 kPa. The reservoir is located in east central Alberta, south of the town of Consort. The formation is a turbidite sand with a limited bottom water aquifer support. The production fromthe pool began with the discovery well 05-15-35-06 W4M and, to date, atotal of 11 wells have delineated a reservoir area of slightly morethan 32 ha. (see Figure 1). Historically, most of the vertical wells in the field experience high water cuts after a relatively short period of production. Thus, a significant portion of the reserves cannot be produced because of water coning. Infill drilling can compete favourably with BOR processes for the recovery of the bypassed oil for much less investment and operating cost. As the existing vertical wells have to be operated above the critical water coning rates to be economic, horizontal wells become another option for infill drilling. The field experience indicates that horizontal wells can reduce the water coning tendency while increasing the oil production. However, further improvement to oil production rate of horizontal wells is still limited by the encroachment of the water cone when the bottom water exists. Therefore a simulation study was undertaken to investigate the feasibility of increasing reserves by infill drilling with horizontal and vertical wells. Model Construction The black oil simulation module (SimBest II) of The Petroleum WorkBench reservoir management package of Scientific Software-Intercomp was used to conduct this simulation study. SimBest II is a three-dimensional, fully implicit reservoir simulator which is capable of handling as many as three fluid phases and five components in a dual and/or single porosity mode.P. 555