Pikes Peak Project: Successful Without Horizontal Wells

Abstract

Abstract The Pikes Peak Steam Project was initiated in 1981 using vertical wells on one hectare spacing. Emphasis later shifted to directional drilling, but no horizontal wells have been used. Wells are initially steam stimulated, but are drilled in three hectare inverted seven-spot patterns and eventually converted to steam drive. Performance at Pikes Peak has remained excellent since inception, with typical early cycle SORs ranging from one to three and recoveries of up to 40% OOIP before drive conversion. Project cumulative recovery is estimated to be over 50% and rising, as third quarter 1995 project performance was 1,330 m3 oil/day from 117 wells. Advantages at Pikes Peak of vertical or directional well development over horizontal well development are proposed and discussed. A vertical well steam stimulation process for bottom water areas is identified and evaluated. Introduction Horizontal wells have rejuvenated interest in selected Western Canadian heavy oil reservoirs using cold production(1–9), steam Injection(10–22), and fireflood technology(23–25). Some of these projects have been highly successful, and there is now a perception among some oil industry upper management teams that a project is not using the best technology unless it employs horizontal wells. Overlooked in this reasoning is evidence that selected projects have exhibited excellent performance using only vertical and directional wells. In the interest of brevity, this paper concentrates on one project and one technology, the Pikes Peak steam project. Emphasis is placed on discussing why vertical and directional well development likely aided project performance. Detailed discussions of other aspects of Pikes Peak project performance are available in the literature(26–29). Project Location and History The Pikes Peak project is located in Township 50, Range 23 and 24 W3M, approximately 65 km east of the town of Lloydminster (Figure 1). The discovery well was drilled in 1970. Primary production was attempted from 1977 to 1980 using reciprocating pumps, but frequent sanding problems occurred and steam stimulation was selected as an alternate exploitation process. Initial tests in 1981 with portable generators, showed sufficient promise for installation of permanent generators and addition of more wells. Higher quality steam slugs yielded very good responses, and systematic expansion was initiated. Directional drilling was incorporated in 1983 to lessen surface impact and reduce costs. Integral project development strategies included selectively drilling inside the oil/water contact and development of effective strategies for conversion from steam stimulation to follow-up steam drive. Geology and Reservoir Description The reservoir contains a viscous crude oil with a gravity of 0.99 g/cm3 and a gas-free viscosity of 25,000 mPa.s at reservoir temperature (18 °C). Van Hulten(30) concluded deposition of the Pikes Peak channel facies was contemporaneous with that of the regional Waseca sands, and channel- sand thickness variations were the result of migrating point bars. A local structural high allows the project area to be free of bottom water. The Waseca channel at Pikes Peak has been divided into a well-sorted, unconsolidated, predominantly quartz, highly permeable (5 to 10 darcies), homogeneous lower unit and a sand/shale interbedded upper unit.