Sand Control Fundamentals & Design D. Koukhani / A. Hooshmand

HOW SANDING OCCURS In most sandstone reservoirs sanding occurs in two stages: First, the rock fails mechanically in the near wellbore area because of changes in and redistribution of the stresses as the bore is drilled or produced. Mechanical failure does not necessarily mean immediate sand production. Then after the rock has failed, viscous drag forces generated by the flow of production fluids erode the failed material into the wellbore and up the flow path to surface. 4/11/2017 HPOGC ENG DEP

Main Geological Characteristics of Sandstone Reservoirs Sandstone minerals can be split into three main groups: Detrital residue Secondary detrital residue Chemical precipitates 4/11/2017 HPOGC ENG DEP

Main Geological Characteristics of Sandstone Reservoirs Sandstone minerals: Detrital residue: Contain minerals from a source rock that have been transported and deposited mechanically, with quartz and feldspar typical of this group. 4/11/2017 HPOGC ENG DEP

Main Geological Characteristics of Sandstone Reservoirs Sandstone minerals: Detrital residue Secondary detrital residue: Clays are representative of secondary detrital minerals that have also been transported and deposited mechanically. 4/11/2017 HPOGC ENG DEP

Main Geological Characteristics of Sandstone Reservoirs Sandstone minerals: Detrital residue Secondary detrital residue Chemical precipitates: Minerals deposited from solution by chemical or biochemical processes. 4/11/2017 HPOGC ENG DEP

Main Geological Characteristics of Sandstone Reservoirs 1. Quartz: Concentration range of 50 – 70% can form up to 99% of the rock. 2. Feldspar: Concentrations of up to 12%, the next most common sandstone minerals after quartz. 3. Heavy mineral 4. Cementing material 5. Other 4/11/2017 HPOGC ENG DEP

Formation of Sandstones Sandstones, like all sedimentary rocks are produced by a combination of Weathering of existing rocks (igneous, metamorphic and sedimentary-older sedimentary). Transport and erosion of the weathered material and diagenesis. Weathering results in the breakdown of the existing rock into smaller particles. These are then moved by wind, water, gravity or a combination of the three. 4/11/2017 HPOGC ENG DEP

Classification of Sandstones Sandstones have been classified by various criteria such as particle size or shape, sorting, mineralogy of the grains or of the cementations material etc. One common method uses the following classification by mineral content: Arkoses Greensands Greywackes Sandstones are also classified by their grain size: Coarse Grained Sandstone. 4/11/2017 HPOGC ENG DEP

Particle Size Measurement Wentworth scale is used to measure grain size: 4/11/2017 HPOGC ENG DEP

Particle Size Measurement Methods: There are two common methods used for determining the particle size distribution of a sedimentary rock: Sieving Laser Diffraction 4/11/2017 HPOGC ENG DEP

Particle Size Measurement Sieving Advantages: Cheap & Usable Key Disadvantages: Not possible to measure sprays or emulsions Measurement for dry powders under 38 microns very difficult Clays difficult to measure Not high resolution Particles not very well dispersed Needs at least 20g Does not measure below 45 microns 4/11/2017 HPOGC ENG DEP

Particle Size Measurement Laser Diffraction Advantages: Flexibility Dry powders can be measured directly Liquid suspensions and emulsions can be measured Entire sample is measured Quicker than sieving Sample size depends on particle size but typically <1g Measures average diameter of particles High resolution Key Disadvantages: Equipment is expensive – specialist test facilities required. 4/11/2017 HPOGC ENG DEP

Comparison between LDS & Sieve Analysis The four main parameters utilized from the grain size distribution analysis are D10, D40, D50 and D90. 4/11/2017 HPOGC ENG DEP

Sampling Methods There are two fundamental methods of sampling sandstone reservoirs – downhole coring and surface sampling. These can be subdivided into: Rotary coring Sidewall coring Bailing Surface sampling of circulated or produced material Samples can be obtained from: Cores Drill Cuttings Junk Baskets 4/11/2017 HPOGC ENG DEP

Sand Face Completion The choice of equipment which is run across the formation interval forms the sand face completion. The selection will be based on whether the well is Open hole or cased and perforated, Vertical, deviated or horizontal, and Expected production conditions 4/11/2017 HPOGC ENG DEP

Sand Face Completion Choices of completions for sand control across the formation face: Screens Frac-Pack Gravel Pack ESS / CHESS Slotted Liner Chemical Considerations 4/11/2017 HPOGC ENG DEP

Screens Different types of screens that use a different filtering media exists: Wire-wrapped screens Have a base pipe with slots or holes around the circumference that is either single-wire wrapped or surrounded by cylindrical sieves of various mesh sizes. Pre-packed screens Employ a different filtering media. A layer of consolidated resin coated gravel is placed around the internal screen assembly and is supported by a shroud or external screen. Premium screens Premium screens are typically an all-metal design, with a metal mesh filtration media and a protective outer metal shroud. 4/11/2017 HPOGC ENG DEP

Wire Wrapped Screen 4/11/2017 HPOGC ENG DEP

Pre-Packed Screen 4/11/2017 HPOGC ENG DEP

Premium Screen 4/11/2017 HPOGC ENG DEP

Frac-Pack Frac-pack is a sand control method by which a propped hydraulic fracture of limited length is created into a weak or unconsolidated reservoir. Wells producing from unconsolidated reservoirs using frac-packs require lower drawdown pressures to produce. The main reasons for using frac-packing as a sand control technique are: By passing formation damage Reduce water coning Controlling sand production Enhance productivity in low permeability formations 4/11/2017 HPOGC ENG DEP

Gravel Pack In a gravel pack, the annulus between the wellbore and a base perforated pipe with wirewrapped screen, is filled with gravel. Advantages Productivity impairment can be minimized by design Especially useful for heterogenous sands in long productive intervals Disadvantages Complicated workovers Chemical compatibility of WBM and produced fluids Risk of incomplete gravel pack leading to premature screen failure Screen damage from erosion and corrosion is a major concern Chemical compatibility of OBM and carrier fluid Can be difficult to use in deviated and horizontal wells Flow control and isolation is complex 4/11/2017 HPOGC ENG DEP

Expandable Sand Screen (ESS) Unique approach to solve sand control problems. Large OD expanded to contact the wellbore stabilizes formation. System designed to resist erosion and plugging. Large ID to maximize well intervention options. Large and uniform flow area to optimize production. Simple deployment minimizes operations costs. 4/11/2017 HPOGC ENG DEP

Slotted Liner tubing sections with a series of slots cut through the walls in an axial orientation. The main limitation of slotted liners is their flow area – an average of 3% and maximum of 6% is accepted. Flow areas of more than 6% are detrimental to the tensile strength of the pipe. 4/11/2017 HPOGC ENG DEP

Slotted Liner Common Slot Profiles 4/11/2017 HPOGC ENG DEP

Chemical Considerations Used in formations with little or no cementitious material. A major benefit is that the wellbore is left free of obstructions. Fundamental principle = bond the quartz grains together using a liquid resin. This will then provide an artificial cementing material between the grains. 4/11/2017 HPOGC ENG DEP

Expandable Sand Screens (ESS) Design & Construction

ESS Design 1 EST Base Pipe 2 3 Woven Filter Outer Shroud Slots open up Sheets slides over one another Slots open up Expandable Base Pipe UNEXPANDED Overlapping Layers of Filter Media EXPANDED ESS has 3 main components, slotted base pipe, slotted outer shroud and filter media in between. Outer shroud protects the weave during deployment. During expansion the base pipe and outer shroud slots open up and thus expand. The filter media consists of overlapping layers and these slide over one another as the pipe expands. It is important to note that the weave aperture of the filter media does note change during expansion – expansion is not critical to ensure effective sand control/clean-up/plugging resistance Expandable Outer Protective Shroud No change in weave aperture 4/11/2017 HPOGC ENG DEP

ESS Manufacture 3 LAYERS SANDWICHED TOGETHER EST Base Pipe Petroweave 1 2 Outer Shroud 3 4/11/2017 HPOGC ENG DEP

Sizes Available External diameter post expansion 3 7/8” 4 1/2” 3 7/8” 4 1/2” 5 7/8” 6 1/4” 8 3/8” 9 1/8” 2 7/8” ESS 4” ESS 5 1/2” ESS These sizes indicate the design limits of the ESS screen. For information only: Expansion ranges are for maximum expansion with fixed cone. When ACE compliant expansion is used final OD’s are less than stated above because expansion is limited by the stroke of the pistons on the tool 3 1/2” ESS 4 1/2” ESS 4 ½” Csg. / 4” OH 7” Csg. / 6” OH 9 5/8” Csg. / 8 ½” OH 4/11/2017 HPOGC ENG DEP

Axial Compliant Expansion Tool The ACE Tool is run after the fix cone for Borehole contact. 1800 psi hydraulic actuation Compliant Expansion speed 10ft/min 4/11/2017 HPOGC ENG DEP

Compliant Expansion Benefits 4/11/2017 HPOGC ENG DEP

Value of ESS - NISOC Total Production = 10,500 bpd Increase with ESS Screens = 5,200 bpd = $208,000/day!!! Project costs (excluding workover) recovered in 5 days 4/11/2017 HPOGC ENG DEP