Abstract

Research aspects for the LASER process were described in a previous 2002 CIM paper (CIM/SPE/CHOA 79011). The research concept has since been field-tested for a single cycle at a pad in Imperial's CSS (Cyclic Steam Stimulation) operations at Cold Lake. The pilot entailed addition of a small 6% volume fraction of C5+ condensate (diluent) into 8 wells during CSS cycle 7. The key pilot objectives were to assess (1) the uplift in Oil-Steam Ratio (OSR) over CSS and (2) the level of diluent recovery.

The overall performance of the pilot to date has been encouraging. The diluent recovered is estimated to exceed original expectations and is similar in composition to the injected diluent. The uplift in OSR was consistent with original expectations.

Suites of monitoring instrumentation and analytical methods were developed to allow quantification of the recovery of injected diluent. In addition, multivariate analysis (MVA) statistical methods were used to develop a model of CSS process performance. This model reduced the statistical background performance "noise" associated with normal base CSS operations and allowed an improved analysis of the OSR plift in the pilot to be made.

Introduction

The LASER process has been described in patents issued recently in both the US and Canada1. It essentially consists of combining thermal and solvent effects in a cyclic mode of operations to improve CSS performance. The preferred solvent for LASER is diluent that is already used to pipeline produced bitumen to markets. In cyclic-type operations, the mixing and contacting of solvent with targeted bitumen is expected to be more effective than in continuous thermal operations conducted at constant pressures.

Background information on LASER technology is described in previous 2002 paper2. The 2002 paper presented

  • a description of both CSS and LASER processes for Cold Lake

  • the laboratory physical proof of principle for the LASER process

  • the validation of that potential using single-well simulations

  • a brief outline of the LASER demonstration pilot scope and design facilities.

The primary objective of the field pilot was to collect sufficient high quality data to allow accurate assessment of key performance indicators such as (1) bitumen uplift and (2) diluent recovery. Based on the initial simulation work conducted with 6% v/v diluent in steam, performance expectations were for an OSR uplift of 33% over CSS and a recovery of 66% of the injected diluent.

Currently, Imperial Oil produces approximately 140,000 bpd of bitumen using the Cyclic Steam Stimulation (CSS) process from its Cold Lake field in east central Alberta. The process is expected to recover approximately 25% of the Original Bitumen in Place (OBIP). Previous work has indicated that if successful, the LASER process could increase this recovery factor by 3–6% OBIP.

LASER Pilot Design

Pilot Location Selection and Well Layout H22 (LASER Pilot) and H21 (CSS Control) pads are located in the northwestern area of Imperial's operations at Cold Lake. The pads provided the most opportune location to conduct the LASER demonstration field test in 2002.

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