Analysis, Logic, Considerations, Mitigations, Risk Assessments and Procedure to Drill Horizontal Gas Well With Separation Factor Up to 0.6 between the Ellipses Avoiding Collision in Exploratory Field. Bio-UC Project at Abu Dhabi, United Arab Emirates

Abstract

In a current oil & gas challenging drilling environment where the fields are becoming very congested, PAD drilling and field grid designs with close proximity wells operation is booming. Drilling challenging wells with high collision risks is common as a result of the requirement to maximize the Asset value of the oil fields. For this reason, the urge for ensuring accurate well placement is becoming critical and as a result high technology methods are required to be in place. Developing new areas where the poor and/or inaccurate drilled wells information (most of them are vertical) affect planning and placement of new wells due to the uncertainty in existing wells trajectories, causing collision issues among the new planning and the "trajectory" of the existing wells, leaving huge quantities of reservoir volume not possible to drain. For this study case, where the reservoir has some complexity due to faults and water, such limitation is critical. The analysis and fusion of new techniques and procedure to manage the risk for the collision were implemented. Directional tools with high level of accuracy measurements were deployed and stringent procedures are put in place. The Analysis, Logic, Considerations, Mitigations, Risk Assessments and a New Procedure implemented to avoid collision issues while drilling horizontal wells with Separation Factor (SF) less than 2 (standard worldwide is equal or above 2 and for this case, it was 0.6). This was developed by the Biogenic / Unconventional team, Drilling Department of Abu Dhabi National Oil Company (ADNOC) Onshore with the support of drilling service company and the approval of the ADNOC Head Quarter, to take advantage of around 0.9 km2 of hydrocarbon area for future drain. The well was drilled successfully and safely, no collision or magnetic interference issue in any trajectory survey were reported during drilling and passing close by the existing well.