MPD in Timor Sea drilling campaign

The International Association Drilling Contractors (IADC) defined the Managed Pressure Drilling (MPD) is an adaptive drilling process used to precisely control the annular pressure profile throughout the wellbore. The objectives are to ascertain the downhole pressure environment limits and to manage the annular hydraulic pressure profile accordingly.

MPD is a new drilling technique that using up-to-date technology to have a quick responds to the drilling problems or another word is that to prevent the drilling problems such as Kick, stuck pipe and lost circultion to occur during drilling.

Kick occurs when the wellbore pressure is less than pore pressure that causes hydrocarbon (HC) fluids flow into the wellbore and toxic gas (i.e. H2S) or fluid may migrate into the surface via annulus, the kick is something that the operators and contractors not wish to happen because if it happens beside hazardous to the well and crews and also it incurs the Non-Productive Time (NPT) hence the drilling cost will be expensive, engineers and researchers are working vigorously find ways how to minimize the NPT associated with the drilling problems. In addition, the stuck pipe occurs when the formation is migrated at the vicinity of wellbore which cause ballooning in the wellbore where the drilling cutting consist of fragmented rock, fine-sands, silt, clays and shale accumulated at the annulus making it is hard the drilling mud/fluids to lift the cuttings to the surface, this normally occurs in horizontal wells when the Bottomhole Assembly (BHA) is moving downward inclination that making rather difficult for mud circulation. Another drilling problems is that lost circulation, as said before the kick occur when the wellbore pressure less than the pore pressure, however in the case of lost circulation is when the wellbore pressure is greater the fracture pressure. Fracture pressure is the limit of the well's ability to bear to the certain pressure. When the lost circulation occurs the expensive drilling mud will flow into the formation hence drilling cost on the drilling mud will be increased and the well cleaning will not effective hence the NPT increases.

The Managed Pressure Drilling (MPD) can be used to mitigated these problems by applying the surface pressure, the MPD is provide a closed pressure circulation vs. open to atmosphere in conventional drilling. There are various types of variants MPD, Constant Bottomhole Pressure (CBHP), Pressurized Mud Cap Drilling and Dual gradient. Dual Gradient is suitable for deep water operation in offshore environment. As exploration drilling in Joint Petroleum Development Area (JPDA) going on in Timor Sea, so it is recommended the company to use the MPD in drilling operation in order to make impossible to be a possible one. PETRONAS has been using MPD in their exploration drilling in one block in JPDA.

It is good for the regulator of Timor Leste to look into the MPD application and recommend to the industries in order to achieve the successful drilling that all parties want. As a researcher and designer on MPD I have no doubt with its application.Evidences have prevailed the successful of the drilling operation.