Sand management/control

Ceramic Sand Screens Applied in Maturing Oil Field Offshore Malaysia

This paper presents the first successful application of ceramic sand screens offshore Malaysia. Ceramic sand screens were considered as a remedial sand-control method because of their superior durability and resistance compared with metallic sand screens.

jpt-2018-10-188537heroto.jpg

This paper presents the first successful application of ceramic sand screens offshore Malaysia. Ceramic sand screens were considered as a remedial sand-control method because of their superior durability and resistance compared with metallic sand screens. Remedial sand control with ceramic sand screens has successfully revived idle wells back to production at a lower total cost, with oil gain beyond the initial target and a higher return on investment.

Field Overview

The field was discovered in July 1967 at a water depth of 250 ft below mean sea level approximately 40 km offshore East Malaysia. The structural configuration of the field is characterized by a simple, low-relief domal anticline resulting from the rollover associated with regional growth faulting. Major hydrocarbon accumulation occurs in eight producing reservoirs sandwiched between shallow gas-bearing reservoirs and deeper gas- and condensate-bearing reservoirs.

Since peak production in 1979, the field has experienced instances of sand production, contributed to by factors such as in-situ stress changes, increases in water production, and a cascading effect from production-operation activities.

The current practice of controlling severe sand production is to bean down the problematic wells and closely monitor sand production at surface over time. Some of the field’s wells had experienced failure and rapid wear when using metallic sand screens, so ceramic screens, with high erosion resistance, were proposed. Because this represented the first such application for the operator, a pilot application was considered for three wells.

Ceramic Sand Screens

Sintered silicon-carbide ceramic material offers unique combination properties. Greater hardness, compressive strength, and elastic modulus offer superior ballistic capability and resistance to wear when confronted with high-velocity projectiles. Excellent corrosion resistance provides high performance in corrosive environments. High thermal conductivity provides heat stability (up to 1,800°C) and minimizes the likelihood of failure caused by thermal shock. The low specific density of the material makes it suitable in applications in which weight requirements are critical.

When the erosion- and corrosion-resistant properties of ceramic material are holistically integrated within a sand-control system, the resultant screen installation is proved to be simple and cost-effective, resulting in reduced complexity compared with alternative sand-control methods. Conventional metallic materials exhibit limitations in withstanding high downhole velocities, commonly resulting in downhole erosional failure and premature loss of downhole sand control.

Ceramic Sand-Screen Design and Working Principle

The sand-screen design consists of a metallic base pipe on which a stack of ceramic rings are mounted. End caps are fixed on either end of the ring stack to hold the rings in a state of compression, and an external sacrificial protective shroud is applied to protect the ceramic rings during transportation, handling, and installation (Fig. 1). The screens are modular in configuration, either as single or multiple modules. The ceramic rings are designed to create keystone or V-shaped gaps to prevent plugging and high laminar flow rates, thus maintaining low pressure drops across the screen. The upper face of the rings, manufactured with integral spacers shaped as spherical bumps ensuring only point contact between the stacked rings, defines the slot sizing and provides flexibility and stability against torsion.

jpt-2018-10-188537f1.jpg
Fig. 1—Ceramic sand-screen assembly.

Slot-Opening-Size Selection With Laboratory Testing

To confirm optimal slot-opening size, sand-retention testing (SRT) was performed using ceramic sand-screen coupons with actual core samples. Core samples were deagglomerated to determine particle-size distribution (PSD) before the SRT. Because of the high content of organic matter in the core sand sample, the wettability of the sand with water was poor and did not allow formation of the sand/water slurry required for laser particle-size analysis (LPSA) and slurry SRT.

Dry-sieve analysis (DSA) was performed using a stack of sieves with the mesh openings fixed on a vibrating plate. LPSA was then performed; DSA and LPSA results were in good agreement.

On the basis of the PSD analysis, a decision was made to perform SRT on ceramic coupons with 150-, 175-, and 200-µm slot sizes. Because of limited sand-sample availability, larger slot-opening sizes were not tested.

For the 150- and 175-μm slot sizes, a steep rise in differential pressure was observed and the slurry test was stopped at the maximum operation pressure. This behavior indicates plugging. For the 200-μm slot size, a steep rise in differential pressure was observed after the start of slurry injection but was followed by a smooth and steady increase of differential pressure up to 23 psi at the end of slurry injection. Replication of slurry SRT for the 200-μm slot size showed a high degree of consistency and reproducibility.

At the beginning of sand injection, the amount of produced sand increases. After reaching a maximum of 0.025 lb/ft² at a volume flow of 20 gal/ft², the amount of produced sand decreases significantly through the formation of a homogeneous sandpack. A virtually constant rate of produced sand at a very low level (approximately 0.001 lb/ft²) was observed above 60 gal/ft². At a volume flow of 100 gal/ft², which marks the end of slurry SRT, 0.044 lb/ft² of sand is produced through the screen coupon.

During slurry injection, the produced sand was collected in fluid batches with a volume of 250 mL each. Only the amount of produced sand in Fluid Batches 1 and 2 was sufficient to be used for LPSA. The LPSA results for produced sand are similar for all samples.

The differential pressure vs. flow-rate curve indicates that a dense sandpack was formed during slurry SRT. The maximum operational pressure of 60 psi was reached at a flowrate of only 0.45 L/min. The nonlinear correlation between differential pressure and flow rate is a result of densification of the sandpack with an increasing flow rate.

After slurry SRT, permeability of the screen coupons was measured by removing the sandpack. Observed permeability reduction from 44.6 darcies before the SRT to 28.1 darcies after the testing indicated residual plugging of the screen coupons, corresponding to a retained screen permeability of 63% after slurry SRT.

Ceramic sand screens, with their ­erosion-resistant properties, could resist the hot-spotting in such well conditions and thereby increase mean time between the failures, further unlocking production potential from the wells.

Tool-Deployment Simulation

An impact test was conducted using actual ceramic sand-screen assemblies in a training well in installation mode to simulate the impact on the ceramic sand-screen assemblies during installation in the following two scenarios:

  • Installation at the sliding side door (SSD) with the ceramic sand screen hanging freely; in this scenario, most of the impact will be cascaded to the tubing through the lock mandrel.
    • The ceramic sand-screen assembly was run in hole (RIH) and set inside the SSD.
    • The lock mandrel was confirmed to be fully set in order to simulate excessive impact.
    • The ceramic sand-screen assembly was retrieved to perform a physical test.
  • Installation of the ceramic sand screen on top of the solid base, where most of the impact will be cascaded directly to the screen.
    • The lock mandrel was confirmed to be fully set in order to simulate excessive impact.
    • The ceramic sand-screen assembly was retrieved to perform a physical test.

The impact test provides simulation of extreme conditions of impact by using heavier 1⅞-in. tool string compared with typical 1½-in. tool string used for installation of the ceramic sand screen. For both scenarios, no physical damage was observed to the ceramic sand screen.

Installation Mode and Procedure

Remedial sand control by workover was found to be uneconomical; thus, a retrofit solution using a slickline unit was considered. Three installation modes were evaluated for the pilot application.

  • Free-hanging mode: The ceramic sand screen was hung at the SSD or nipple profile using a lock mandrel.
  • Straddle mode: The ceramic sand screen was straddled across the perforation interval or SSD.
  • Pseudostraddle mode: The ceramic sand screen was set using a nippleless plug across the perforation interval or SSD with an additional plug set near the bottom assembly (approximately 10–15 ft from the bullnose).

For simpler and quicker installation on the three pilot-candidate wells, the free-hanging mode was selected.
A newly developed RIH program was consolidated on the basis of the impact-test results, software simulation, in-house wireline operating procedures, and installation guidelines. A detailed discussion of the field application and results for this method in the three candidate wells is presented in the complete paper.

Conclusions

For all three candidate wells offshore Malaysia, ceramic sand-screen technology has successfully been applied, enabling effective remedial sand control in a highly erosive environment. Total application costs were 31% lower, with a return on investment 51% higher, compared with metallic sand screens. The idle wells were revived to production with a total oil gain 17% higher than the planned target gain.

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 188537, “First Successful Application of Ceramic Sand Screen in Maturing Oil Field, Offshore East Malaysia,” by Sulaiman Sidek, SPE, Kellen Goh Hui Lian, Yap Bee Ching, Kukuh Trjangganung, Bahrom Madon, SPE, and Zainuddin Yusop, Petronas, and Bhargava Ram Gundemoni, SPE, Richard Jackson, and Peter Barth, 3M Technical Ceramics, prepared for the 2017 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, 13–16 November. The paper has not been peer reviewed.