ASSESSMENT OF SUSTAINED CASING PRESSURE ON WELL INTEGRITY

Sustained casing pressure (SCP) is commonly known as one of the well integrity problems in oil and gas industry. In fact, the term of „annular pressure‟ implies a similar definition to SCP (Attard, 1991) if the annular pressure is unmanageable or leaking in well components. The leaking problem can be due to tubing/casing leak, poor primary cementing job and interuption to cement integrity due to the pressure and temperature changes when the well starts to produce hydrocarbon. Hence, there is a necessity to manage SCP effectively in order to ensure the integrity of well. This project is based on modeling approach, where the objective is develop a series of computer codes with the reference of existing pressure bleed-off time Mathematical model. The results generated from the model is based on effect of temperature, type of gases filled in annulus and depth of well. These 3 type of parameters can affect the pressure bleed-off time in annulus itself, provided the condition where the size of needle valve is fixed. From the model generated in Wolfram Mathematica 8.0, it is able to notify engineer to receive any early sign of warning if the well is suspected a leakage. Meanwhile, based on the matching process of field data and modeled data, engineers will be able to aware and determine whether the occurence of annular pressure is due to thermal induced annular pressure buildup or it is because of the leakage in well components. Finally, this model is economic and able to save cost until the well is needed for any further confirmation. In addition, the project also studied the effect of SCP on the well integrity. With this, the well will eventually loss in production, severe failure in well‟s integrity or consider the worst case scenario, the excessive of SCP may cause an underground blowout at subsurface. Currently, the report was referred 18 documents as references in this research topic.