Method and apparatus for hydrogen sulfide monitoring

A method for identifying the presence of hydrogen sulfide in a subsurface formation penetrated by a wellbore, comprising:

• lowering a formation evaluation tool into the wellbore, the tool comprising a housing, at least one coupon with a surface that is optically reactive to the presence of hydrogen sulfide, and at least one passage for conducting formation fluid to coupon drawing formation fluid samples from the subterranean formation into the formation evaluation tool;
• delivering formation fluid to coupon via the passage;
• retrieving the formation evaluation tool from the wellbore;
• and
• inspecting the coupon for an optical reaction.

A method for identifying the presence of hydrogen sulfide in a subsurface formations penetrated by a wellbore, comprising the steps of:

• lowering a formation evaluation tool into the wellbore, the tool including a housing having at least one coupon that is reactive to the presence of hydrogen sulfide and a passage for conducting formation fluid to coupon drawing formation fluid samples from the subterranean formation into the formation evaluation tool delivering formation fluid to coupon via the passages;
• retrieving the formation evaluation tool from the wellbore;
• and
• inspecting coupon for an optical reaction.

A method of reservoir analysis, comprising:

• lowering a formation evaluation tool into a wellbore that penetrates a reservoir, the formation evaluation tool comprising at least one coupon that is optically reactive to the presence of hydrogen sulfide;
• flowing formation fluid through the formation evaluation tool;
• exposing the at least one coupon to formation fluid upon the formation fluid entry into the wellbore;
• taking temperature readings of the formation fluid;
• collecting formation fluid samples within the formation evaluation tool;
• retrieving the formation evaluation tool from the wellbore;
• inspecting the at least one coupon for an optical reaction;
• and
• estimating the hydrogen sulfide content of the formation fluid within the reservoir utilizing the inspection of the optical reaction of the at least one coupon and the temperature readings of the formation fluid.

A formation evaluation tool for drawing fluid from a subterranean formation therein, comprising:

• a housing;
• and
• at least one coupon operatively connected to the housing, the at least one coupon being optically reactive to the presence of hydrogen sulfide positioned in the housing;
• wherein the at least one coupon is adapted to be exposed to reservoir fluid upon the reservoir fluid entry into the apparatus.

A formation evaluation tool for drawing fluid from a subterranean formation therein, comprising:

• a plurality of coupons that are optically reactive to the presence of hydrogen sulfide;
• a housing capable of retaining the coupons and having a passage for communicating formation fluids between a wellbore and the coupons;
• a temperature sensor;
• a probe capable of flowing formation fluids into the formation evaluation tool;
• wherein when the formation fluids are pumped through the formation evaluation tool the coupons are exposed to the formation fluid upon the formation fluid entry into the formation evaluation tool;
• and
• wherein the surface of the plurality of coupons are capable of changing color upon contact with hydrogen sulfide and can be interpreted to determine the hydrogen sulfide content in the formation fluids.