By: Ing. Andrés Marcano – CEMENT SPECIALIST
Do you have problems with your Cement Job?
A key point to take into account, during the design of slurry and the execution of Cement operation is: GAS MIGRATION AFTER CEMENTING. Here are some tips to help you OVERCOME that problem.
The flow of gas into the annular after cementing has been a problem in the oil industry for Many years. researches on these situations and theories have been developed but in reality, the problem has not been entirely corrected. Experience indicates that the main reason for this problem has been poor monitoring and control of operational parameters during the cementing operation and/or misguided selection of proposed cement slurries. The consequences of gas migration after cementing well are several, including communication between different areas or reservoirs, pressurized shallow areas, environmental damage and well kicking or even blowout have occurred due to this cause.
The success of cementing Job is based on good planning, the selection of the proper slurry design and the control and verification of the desired parameters by means of pre-operational tests in cement laboratories, such as: transition time (where values should be in the range between 10 minutes to 20 minutes), cement gel resistance (values should be in the order 500 and 1000 lbs/100feet2) and filter loss values below 20 cc/30 minutes.
It has been verified, then by means of CBL/VDL records, that there was not gas flowing in the annular after cementing operation, when the design parameters planned in the laboratory are met and then reproduced in the field during cementing Job.
