Abstract In a geochemical prospecting method, samples are analyzed for a critical carbonate mineral which contains most of the hydrocarbons in the sample. The mineral is almost always dolomite, calcium-magnesium carbonate, but may be other carbonate minerals, such as iron carbonate, or even calcium carbonate. The critical carbonate should be separated from any other carbonates which are present in significant amounts. Gases are then released from the critical carbonate. Released gases are analyzed for hydrocarbon content. Preferably, gases are released by acid treatment. These gases are then analyzed for carbon dioxide content as a measure of the carbonate mineral. The ratio of hydrocarbons per unit of critical mineral is then plotted to form a geochemical prospecting map.
The method of claim 1 in which said critical carbonate mineral is dolomite.
Claim 2
Dependent Claim
61 words
The method of claim 1 in which said sample is first screened to eliminate large particles, the concentration of hydrocarbons and critical carbonate mineral in the fine fraction passing through the screen then being determined, the amount of at least one hydrocarbon per unit of critical carbonate mineral in the fine fraction then being plOtted to form the geochemical prospecting map.
Claim 3
Dependent Claim
66 words
The method of claim 1 in which said critical carbonate mineral is separated from at least other carbonate minerals before hydrocarbons are released from said critical carbonate mineral, the fraction containing said critical carbonate mineral is analyzed for hydrocarbon content and critical mineral content, and the map is plotted showing the concentration of at least one hydrocarbon per unit of critical carbonate mineral in said fraction.
Claim 4
Dependent Claim
13 words
The method of claim 4 in which said critical carbonate mineral is dolomite.
Claim 5
Dependent Claim
70 words
The method of claim 5 in which said sample is screened to reject large particles, the fine fraction is treated first with controlled pH citrate solution to remove calcite and is then treated with hydrochloric acid to release hydrocarbons held by the dolomite and carbon dioxide in said dolomite, the amount of carbon diodixe then being measured to determine the amount of dolomite in the fine fraction of the sample.