Reservoir Management Challenges in Cluster Drilling on a Giant Onshore Oil Field Under Redevelopment in United Arab Emirates
Authors: Martinez Santiago Maryvi , Ortiz Jhon , Salawu Mohammed , Priyadarshini Bhanu , Alhammadi Mariam 
Published: November 2020

In order to support a new strategy for the development of the Northern part of a large carbonate reservoir, a multi-disciplinary and comprehensive approach was implemented to resolve the subsurface and surface issues associated with execution of the strategy. The plan is to have a balanced well count per year, optimise the existing geological target in the development plan, propose and implement artificial lift requirement, firm up the need for future Pattern Water Injection schemes.

Consequently, a large number of additional producers and injectors is required to be drilled within a highly congested surface and hence the need to embark on Pad drilling to overcome some of these challenges. Pioneering the On-pad drilling in the field enable to increase and sustain the oil production target rate planned in Q1-2021 in addition to convert the Reservoir Development scheme to pattern injection.

In order to expedite a robust and effective planning process, a timely and coordinated reservoir monitoring plan was put together and executed to reduce risk of gas for the new wells. In stratigraphically complex areas, pilot holes were recommended to help place and optimize well trajectories in the horizontal section. Key wells were nominated as candidates for accelerated acquisition of pressure and saturation data as critical requirement to understand fluid movement and consequently de-risk new target for the PAD wells.

- A drilling optimisation exercise which include the following

- Mapping the target azimuth to the Plat Orientation for ease of drilling

- Designed wells trajectories with long departure & high turn.

- Rigorous anti-collision analysis. Very Difficult but detailed well planning process. Wells in area of moderate- high Gas/Water Saturation.

- Utilisation of advanced completion technology to mitigate unwanted gas & water production.

- Timely delivery of drilling proposals

- The wells should be within the minimum recommended safety factor as per company drilling policy.

The Cluster Drilling came into execution since January 2019. The main highlighted:

- Well placement optimization for 24 on-pad drilling wells (8 platforms) by multidisciplinary subsurface integration. Should be available the Flexibility of shortening some wells H.H drain due to risk of high collision with existing wells.

- Pioneering the On-pad drilling in the norther field successfully completing so far 3 Plats with 12 oil wells on sweet spots in 2019, estimating the associated oil potential in 24 MBPD.

- Accommodated the required number of wells based on the company production target ahead of time, as per 2018-2023 business plan with the first well commissioning in Q1 2020.

- To take maximum advantage, during PAD drilling planning process the reservoir monitoring plan should be prepared liaise with the underlying reservoirs, besides, with base on the new data findings allow to introduce changes at least in quarterly base.

- Cost saving was achieved by optimizing Gas Lift completions to 6 out of initially planned 12 wells based on simulation-surveillance integration work.

- The Integrated Team organisation has worked well resulting in faster and higher quality deliverables.