Single-Trip Multizone Gravel Packing

Abstract

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper IPTC 12388, "Single Trip Multi-Zone Gravel Packing - Case Study at Handil, Bekapai and Sisi-Nubi Fields," by Mark Banman, Eric Delattre, Mohammad Sofyan, and Siswara Suryadana, Total E&P Indonesia. It was originally prepared for the 2008 International Petroleum Technology Conference, Kuala Lumpur, 3–5 December. The paper has not been peer reviewed. Stacked gravel packs involve limited technical risk, but require considerable rig time when completing deep multizone, sand-control wells. Four field developments are challenging the conventional approach to completing long sand-control zones by using newer technologies. Nineteen wells have been completed with single-trip multizone (STMZ) technology comprising 77 frac packs/gravel packs. Introduction For many years, simple stacked gravel packs have been used in Indonesia as the primary cased-hole sand-control method. This kind of completion involves limited technical risk, but requires considerable rig time and cost when completing multizone wells with sand-control completions. Because of escalating prices, operators completing wells with multizone gravel packs are striving to cost-effectively produce as many unconsolidated reservoirs within a single wellbore as possible. The development of the Handil, Bekapai, Sisi, and Nubi fields illustrates the challenge of maximizing the recoverable reserves from such wells while minimizing the incremental cost of completing additional zones. These four fields are part of the giant Mahakham delta complex on the east side of Borneo Island (East Kalimantan, Indonesia). Two of these fields, Handil and Bekapai, are redevelopment projects, while Sisi and Nubi fields are new developments. All the fields are in relatively shallow waters. In each of the fields, production comes from two major sand/shale sequences. There is a series of deeper gas sands that produce without sand control and a series of shallower, oil-/gas-bearing sands that require sand control for efficient production. The shallow hydrocarbon reserves are distributed over a large vertical interval. This leads to wells with long multizone gravel-pack completions. Conventional gravel-pack techniques for multiple zones consist of a series of individual gravel packs, each one placed on top of the one below ("stack pack"). This generally uses at least two service-string trips per zone, one for perforating and the other for gravel packing. Use of a packer plug to isolate lower zones when perforating adds one additional trip per zone. A typical well in the Mahakham delta has five zones and would need 14 service-string trips and consume 20 to 30 rig days to install the stack pack together with the upper completion depending on the depth, perforating time, and use of packer plugs. This represents a significant capital cost.