Application of “casing and liner while drilling" technology for OMV Pakistan
Research output: Research › Master's Thesis
Present day challenges faced by oil and gas industry remind us to find ways which are more reliable, economical and robust. New methods for drilling and completing the wells are required. Mechanical instability of the wells compels us to think of new drilling methods. Casing while drilling (CwD) is one of the techniques which make us drill more reliably and more confidently. The approach of using CwD is that casing is used in place of a drill string. It means the well is drilled and cased simultaneously. When well is drilled to total depth (TD), casing is cemented in place. Unconsolidated formations having swelling and caving-in problems are best suited for this. Loss circulation zones are also potential candidates. This method of drilling has got several advantages over conventional drilling methods. It reduces the hazards related to excessive pipe handling. Mud fluid loss is reduced and higher equivalent circulating density (ECD) can be obtained with the same mud weight. This is due to the “plastering” effect of casing drilling on borehole wall. Thus, Casing with drilling improves overall drilling efficiency by reducing non-productive time (NPT). CwD has been in use for quite some time and its purpose is now well understood. This technology can be used with present day rigs with little or no modifications. Depending on the utilization, retrievable and non-retrievable bottom hole assembly (BHA) and bit systems can be used. In this thesis, the importance of Casing while drilling (CwD) & Liner while drilling (LwD) along with its technical feasibility in the fields of OMV Pakistan is discussed. This thesis is done to find the best possible match between the requirements of the company, availability of different equipment and service providers present in the market. Finally, a new wellbore “Miano NN” is designed and cost analysis is done to prove its applicability in company’s current operations.