A horizontal well drilled by Gulf in the Edam area is currently producing at more than seven times the rate of an average vertical well.
A black oil simulator was used to history match several years performance of two adjacent vertical wells close to the horizontal well. The resultant reservoir description provided the basis for horizontal well performance forecasting including a parametric sensitivity study.
Actual horizontal well performance over several months of production was available for tuning the model in an effort to estimate probable long term behavior. It was observed that certain reservoir parameters such as viscosity, the distribution of water saturation and permeability which could not be firmly established for this type of reservoir can have a substantial impact on horizontal well performance.
Production performance could also depend upon horizontal well characteristics arising out of completion and production practices. Such as effective completion length and artificial lift. Finally, the reliability and applicability of simple analytical methods for planning and evaluating horizontal wells are discussed.
Gulf Edam West Horizontal Well A5: C10-24-48-21 W3 was spotted on December 10th, 1988. Only three horizontal wells were drilled in Saskatchewan prior to this well. At the present time, twenty horizontal wells have been drilled in the province and another twenty are awaiting drilling licenses from regulatory bodies.
The well A5: C10-24 was drilled horizontally for 558 meters (m) of which 418 (m) encountered the Sparky heavy oil formation. Production from the well commenced on January 24, 1989 and is currently stabilized at 50 m3 /d. This is ten times the rate of an average vertical well in the section. Figure 1a shows the location of the horizontal well A5: C10-24. The section is developed on 16 hectares (ha) spacing and has nineteen vertical wells completed in the Sparky Sand.
The objective of this paper is to discuss the first year performance of the horizontal well and compare it to the offsetting vertical wells completed in the Sparky Channel Sand in this section. The paper refers to the drilling and completion techniques used. It reviews the initial production methods utilized to control water and sand production. It outlines numerical and analytical techniques wich were used to evaluate the horizontal well performance and predicts production forecast. It also discusses the encouraging economic indicators which augers well for the development of Sparky Channel Sands by horizontal wells. In addition, the paper refers to a second successful horizontal well which was drilled in the section (D3: B9-24-48-21 W3), commenced production in January 1990. The location of this well is shown in Figure 1b.
The Sparky Sand in Edam can be subdivided into two major facies: regional and channel. Regionally, the Sparky Sand is characterized by a coarsening-upwards sheet like sandstone, interbedded with silstone/shales. In some areas, this regional facies and parts of the underlying formations have been eroded by channels which were subsequently filled by sandstone. The sandstone filled-channel in Section 24 is well sorted and slightly coarser grained than the regional facies.
