Highlights and Unique Lessons Learnt From Multiple Interventions on a Deepwater Asset in Malaysia

Abstract

A field is a faulted anticline structure lying in a deepwater turbidite environmental setting, which consists of four main sand bodies that were targeted over two phases of development. The field is accessed via a Tension Leg Platform (TLP) structure, about 100KM from the shores of Sabah, with water depths of around 1600ft. Most of the historical production in the field comes from two reservoirs, which have had varying degrees of performance across the field with challenges ranging from secondary gas caps, to increasing water cuts and formation impairment. Part of the field management strategy has been to either introduce water injection to maintain pressure, or GOR limit relaxations when additional pressure support is not possible. Difficulties that add to the field is the non-uniform depletion of the reservoir due to either structural compartmentalization (which is highly prevalent in this field) or sedimentary complexities due to thin bed production, uncertain fluid movements and skin introduced via fines migration. Since 2018, multiple logging campaigns have been conducted on both reservoirs to characterize and diagnose the nature of inflows with various solutions proposed depending on the outcomes. To date, the field has employed multiple gas shut-offs, water shut-offs and acid stimulation jobs that have led to highly profitable successes along with failures that have informed future and ongoing work in the field. This paper will attempt to summarize the various interventions made on the field and the subsequent solutions proposed and implemented, which has led to significant incremental gains from the brownfield where successful and lessons learnt where solutions proposed were less optimal. The multiple campaigns conducted on this field has also led to great efficiencies in the interfaces between the various groups, from vendors, to wells, asset and subsurface with results and mitigations regularly proposed and supported by the various joint venture partners and regulators in the field. The uniqueness of the challenges faced in this Deepwater field is the ability to intervene ‘relatively’ cheaply to diagnose the problems given the dry-tree nature of the TLP, as opposed to subsea type wells requiring huge operational costs that are commonly found in other similar Deepwater type developments. This provides the unique opportunity to trial multiple state of the art type intervention techniques where even the smallest possibility of success potentially pays off for multiple campaigns. The technical learnings should therefore be highly applicable to many assets, and the ways of working and interfacing that will be demonstrated should be replicable in other places.