Temana Field Pilot Implementation : A Shift In Sand Control Philosophy To Improve Well Performance
Authors: Wan Mohamad Wan Amni , Jadid Maharon Bin , Wahba Mahmoud Abdrafea 
Published: November 2008

The Temana field consists of unconsolidated reservoirs which require active sand control. Conventional Internal Gravel Packed (IGP) technique has been widely applied as it has provided a reliable means of abating sand production. These completions however, have shown high skins (&gt;15) which had increase with time due to fines migration into the packed area especially with the advent of water production. In many cases, flow efficiencies were reduced by 70% and this had severely affected well performances with aging.

Stand Alone Screens (SAS) and Expandable Sand Screens (ESS) had also been applied in some fields with mixed success especially for high angle or horizontal wells. Experience gathered from these previous sand control measures coupled with the emergence of improved design and production of SAS has enabled a shift in our sand control philosophy.

Critical Drawdown Sanding Pressure (CDP) consideration plays an important role in the new sand control strategy we recently applied. To ensure that the CDP does not exceed during well production, we focus our attention to maximize well productivity by implementing open hole completion at high angle of trajectories (70 deg or even horizontal). Furthermore, the reservoir sections were drilled with non damaging drill-in fluid treated with enzyme breaker and screens were run in conditioned, solids free mud to minimise plugging.

Proper sizing of the screen slot size is critical to ensure that screens are not plugged as commonly experienced in SAS applications. Annular flow were minimised by running constrictors suitably placed with the screen assembly. Finally, strict enforcement of slow bean-up policy during the initial production of the new wells has maintained the screen's integrity in the wells completed so far.

This paper describes our new sand control application and the excellent production performances achieved from the new wells in the recent drilling campaign in Temana.

Introduction

Temana field was discovered in 1962 and brought into production in 1979. The field is located approximately 30 km West of Bintulu in a water depth of approximately 96 ft. It consists of three hydrocarbon accumulations, namely Temana West, Temana Central and Temana East (Fig. 1). The field has undergone a complex tectonic history and is highly faulted and compartmentalized.

The latest development is from the existing structure Platform A, which penetrates the Temana Saddle, which is located in the southeastern part of Temana Central. The main reservoir target is the I-65 sand. The sand has a fining upwards log signature with a sharp base at the bottom of the sand. The sand contains light oil of about 41.1 deg API with reservoir pressure of 1,553 psi, average porosity of 26% (oil) and effective permeability of more than 1 Darcy. The main drive mechanism of this reservoir is depletion drive with weak to moderate aquifer support.

There are 7 existing platforms (Fig. 2) with two additional production processing facilities platforms. About 44 wells out of 74 wells of the existing oil producer wells were completed with cased hole gravel packed (IGP) and only 2 wells were installed with premium screens in horizontal open holes. Based on the well test data for these wells for a similar type of reservoir, the average skin is 10–15 even after immediate production and increase up to 20–30 after longer years of production. The average PIs of these wells typically ranged between 1–20 stb/d/psi. Investigation shows that the eminent cause of increasing skin or pack impairment and deterioration in the production wells is due to fines movements packing into the gravel-packed sand and this was aggravated when water breaks through.