Soil gas surveys can quickly ascertain at low cost the oil and gas potential in both mature and frontier regions as well as pinpoint areas for focused exploration and follow-up drilling. Our unique hand-portable sampling system allows access to environmentally sensitive areas, forested regions, fields in crop and difficult terrain. Petro-Find has also developed a passive sampler for surveys in wet, swampy and muskeg areas. A soil gas survey is the only feasible exploration method to evaluate large acreage blocks. Petro-Find's lab in Saskatoon, Saskatchewan, equipped with the latest technology, can offer quick turnaround on analysis of light hydrocarbons as well as CO2, helium and hydrogen.

A contract with a client includes the following information: area to be surveyed, expected starting and completion dates, number of samples, cost/sample and sample density. Petro-Find can usually obtain the required base maps from commercial sources.

Soil gas samples are usually taken on roughly a quarter-mile to one-mile spacing for reconnaissance surveys and as close as 200 meters for high-density surveys. Coordinates of each sampling point are established by GPS. A cordless rotary drill drives a special gas probe to a depth of 3-4 feet. The depth of sampling avoids contamination by any methane resulting from biological activity in near-surface soils. Soil gas is drawn by a syringe and injected into a pre-evacuated vial, which is shipped to Petro-Find's lab at Innovation Place in Saskatoon.

The use of the direct probe requires dry soils. Impediments to field operations with the direct probe are mainly wet soils, especially during spring breakup. No samples are taken for at least two days after a heavy rain because of the downward flushing of hydrocarbons in pore spaces. A newly-developed passive probe allows sampling in wet sediments such as floodplains and muskeg as well as shallow waters.

The analysis, interpretation of data and final reports including contoured maps are currently done in Saskatoon. A gas chromatograph equipped with FID/TCD detectors, back flushing and an autosampler provides fast turnaround on analysis of the light hydrocarbons and CO2.The lab's location of less than one day's travel time from most major gas and oil districts in Saskatchewan and Alberta is also a major factor in the quick turnaround time after sampling. The International Airport at Saskatoon allows samples to be flown in from remote locations as well as from overseas projects.

The centralized lab facilities with fast turnaround time has the following major advantages:

• A quick turnaround on sampling and analysis allows the follow-up of interesting trends before demobilization. Real-time decision-making thereby minimizes the number of trips necessary to adequately explore an area.

• Field efforts are optimized by providing intelligent location of infilling data points during a single survey day while minimizing the uncertainty from almost daily transient changes in soil gas concentration.

• Cost savings for the client and Petro-Find. The accurate depiction of data at the time of the survey optimizes initial deployment of equipment thus avoiding the need to remobilize to the site for additional data.

• It allows for the immediate checking of data that appears to be in error (i.e. too high or too low).

The planar coordinates (XY) of each sampling point are recorded by a GPS as well as in a field noteboook, downloaded to a computer at the end of each day's activities and plotted on a georeferenced base map to act as a guide for the next day's field work. The sample locations and associated concentrations for the analytes as well as ethane+ (total ethane, propane and butane concentrations) are plotted on clear overlay film and contoured using a triangular, non-gridded computer program. For some reconnaissance surveys where the transects are very wide apart, bubble maps are produced instead. Petro-Find is self-sufficient in all aspects of map creation to guard against information leaks.

The major outputs include: