Horizontal Gravel Packing Research Articles

Analysis of Shunted Screen Gravel Pack Process and Calculation of Friction in Deepwater Horizontal Wells

Shunted screen gravel packing is a kind of technology which is difficult to complete gravel packing with the conventional method in low fracture pressure formation and long wellbore length condition. According to the characteristics of LS 17-2 deepwater gas field, the shunted screen packing tool was designed and the gravel packing process and packing mechanism were analyzed. The variation law of the flow friction, flow rate distribution in multichannel, and other parameters of the shunted screen gravel packing were analyzed and calculated. The friction calculation model of different stages of gravel packing was established. A gravel packing simulation software was developed to simulate the friction in different stages of shunted screen gravel packing. The parameters such as sand-dune ratio, pumping sand amount, packing length, and packing time in the process of packing were also calculated. In deepwater horizontal well gravel packing, the results show that the friction ratio of the string is the largest in the stage of injection and α-wave packing. While the friction increases rapidly in the stage of β-wave packing because the carrier fluid needs to flow through the long and narrow washpipe/screen annulus. Particularly when the β-wave packing is near the beginning of the open hole, the packing pressure reaches the maximum. The calculated results are in good agreement with the measured results of the downhole pressure gauge. The model and software can provide technical support for the prediction and optimization of gravel packing parameters in the future.

A Remotely Controlled Downhole Valve Used for Completion Installation

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 166271, ’A Case Study of Using a Remotely Controlled Downhole Valve for Completion Installation,’ by Keith Oddie, SPE, and John O'Hara, SPE, Halliburton, and Luis Paz, SPE, Hess Corporation, prepared for the 2013 SPE Annual Technical Conference and Exhibition, New Orleans, 30 September-2 October. The paper has not been peer reviewed. On the basis of a case study in Equatorial Guinea, this paper demonstrates how barrier provisions with remotely controlled open/close technology capabilities enable interventions to be removed from a completion design. The technology described was used in a horizontal subsea producer well drilled to 3460 m. The paper will illustrate how combining downhole electronic control with a full-bore hydraulically operated barrier valve removes any need for running control lines to the surface. Surface-applied pressure and time combinations were used to command remote actuation of the valve. Introduction The Ceiba field is located 35 km offshore Equatorial Guinea, west Africa, and is 241 km south of the capital, Malabo. Located in approximately 700 m of water and in one of six subsea clusters in the development, this well was identified as a suitable candidate for inclusion of the technology outlined in this paper. To maximize reservoir recovery in this field, the completion strategy included a horizontal openhole gravel pack to provide downhole sand control. The completion engineers felt that this strategy would help meet production objectives such as inflow performance. However, it would also require the well to be drilled at a highly deviated trajectory, which would increase the likelihood of the production packer being set at a deviation beyond conventional slickline capability. The remotely controlled downhole valve offered an alternative plugging method to set the packer, test production tubing, and commission subsurface well-control equipment requiring well interventions, and therefore was included for consideration in the well design. The well design would later confirm that the valve would be installed at a deviation greater than 70°. Plug deployment with wireline and tractor was evaluated in terms of risk and exposure to cost, and from the results of the evaluation, it was concluded that remote technology should be included in the basis of design. A landing-nipple profile located below the packer provided contingency in the event that the remotely controlled valve failed to close. The final subsea completion design required that the 547-m reservoir section be drilled along a horizontal trajectory, the openhole horizontal gravel-pack system be installed, and the gravel pack be performed. Retrieval of the gravel- pack service tool and wash pipe would mechanically close the fluid-loss control valve to provide isolation from the reservoir during deployment of the upper completion. It would also provide a means of applying the pressure and time signature required to close the barrier valve.

Decade of Stimulation Experience in the Deepwater Gulf of Mexico

This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper SPE 159660, ’A Decade of Deepwater Gulf of Mexico Stimulation Experience,’ by Lee N. Morgenthaler, SPE, and Leigh A. Fry, Shell E&P, prepared for the 2012 SPE Annual Technical Conference and Exhibition, San Antonio, Texas, 8-10 October. The paper has not been peer reviewed. The deepwater Gulf of Mexico is a technically and economically challenging production environment. High rates and ultimate recoveries are required per well to offset high development costs. Stimulation treatments maintain wells at peak production rates and accelerate reserves recovery. In these complex layered reservoirs, stimulation is necessary to ensure recovery volume. The primary objective of stimulation is to restore impaired well/reservoir connectivity. Successfully identifying the cause and location of impairment is required. Looking back over a decade of experience in this challenging environment yields useful insights as the industry moves into new deepwater provinces. Introduction Shell’s deepwater development began in 1991 with the Tahoe subsea prospect tied back to the Main Pass 252 platform. Development continued with the Auger, Mars, Ram Powell, Ursa, and Brutus tension-leg platforms (TLPs) and many subsea fields that tie back to them (Fig. 1). Most of the reservoirs producing to these structures are geologically young turbidite sands that require sand control. Initially, all of the fields were geopressured significantly above hydrostatic and were significantly undersaturated. The soft compacting sands and aquifer support often provide sufficient energy to achieve adequate recovery by depletion. The hydraulic fractures created in the frac-pack process provided lower skin values with minimal use of acid. The horizontal openhole gravel packs used acid-soluble bridging agents to stabilize the wellbore during gravel packing. The bridging agents were then removed with acid washing. Because most of these sand-control completions were cased-hole gravel packs or cased-hole frac packs, most of this paper refers primarily to the experience with those completion types. As the fields matured, there were more subsea-tieback developments. Stimulation campaigns generally focused on the direct-vertical-access (DVA), or dry-tree, wells of the TLPs. However, stimulation of subsea wells has been highly profitable, and technology has been developed to reduce the subsea-intervention costs to make these interventions more attractive. The complex operations on TLPs introduce challenges when planning and conducting stimulation operations. Logistics coordination and proper management of returning wells to production are critical to realize production gains and to meet environmental-discharge regulations and goals.

Ultralightweight Proppants: An Effective Approach To Address Problems in Long Horizontal Gravel Packs Offshore Brazil

Summary Operators developing reservoirs and producing them from deep and ultradeepwater wells are pushing the technical limits regarding horizontal extension. Deepwater wells completed in unconsolidated formations usually have low fracture gradients, severe leakoff zones, and/or significant washouts. Long horizontal open holes, therefore, may become technically difficult or economically unfeasible to gravel-pack with the use of conventional fluids and gravels. Typical completions in offshore Brazil start from a 9⅝ - or 10¾-in.casing, in which a 5½-in. premium screen and tubular string is hung along an open hole drilled with an 8½- or 9½-in. bit. Horizontal extensions range from 980 to 4,000 ft. A variety of openhole gravel-pack techniques proved to be complex and costly, but ultralightweight (ULW) proppants have enabled simpler and more-cost-effective gravel packing in these longer horizontal open holes. The reduced gravel density allows a significant reduction in pumping rate that avoids fracturing the formation, minimizes fluid loss, and eliminates the risk of premature screenout caused by excessive gravel settling. ULW-proppant technology was introduced to Brazil in 2005 and has been applied successfully to gravel pack wells under extreme conditions such as low fracture gradient, severe fluid loss, and washed-out zones. ProppantULW-1.25 has proved to be effective for packing wells with narrow sections through the openhole interval, frequently found in horizontal wells completed through shale zones that are isolated by reactive packers and/or mechanical external casing packers. ULW-1.75 was introduced in Brazil in 2007 and has largely replaced ULW-1.25 for gravel packing wells in which an improvement in the operational pumping window is required. A combined package comprising ULW-1.75 during the alpha-wave phase and ULW-1.25 during the beta-wave phase is also discussed. This paper summarizes the procedures and results of almost 60 wells that have been gravel packed with the use of ULW-proppant technology pumped for a local operator.

Ultralightweight Proppants for Long Horizontal Gravel Packs

This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper SPE 150581, ’Ultralightweight Proppants: Best Practices for Long Horizontal Gravel Packs Offshore Brazil,’ by A.T. Jardim Neto, F.G.M. Prata, and J.R. Gomez, Baker Hughes, and C.A. Pedroso, SPE, M.O. Martins, and D.N. Silva, SPE, Petrobras, prepared for the 2012 North Africa Technical Conference and Exhibition, Cairo, 20-22 February. The paper has not been peer reviewed. Operators developing and producing reservoirs with deepwater and ultradeepwater wells are pushing technical limits with horizontal extension. Deepwater wells completed in unconsolidated formations usually have low fracture gradients, severe-leakoff zones, or significant washouts. Long horizontal open holes may become technically difficult or economically unfeasible to gravel pack by use of conventional fluids and gravels. Use of ultralightweight proppants (ULWPs) has enabled gravel packing in these longer horizontal open holes. The reduced gravel density allows a significant reduction in pumping rate to avoid fracturing the formation, minimize fluid losses, and eliminate the risk of premature screenout because of excessive gravel settling. Introduction Horizontal openhole gravel-pack (HOHGP) completions are preferred by many operators, especially in permeable unconsolidated formations. Offshore Brazil, especially in the Campos and Espirito Santo basins, HOHGP completions are used to develop post-salt reservoirs. The most common gravels used in the early wells were natural gravels and conventional ceramics. The particle densities (2.65 to 2.73 g/cm3) caused much difficulty with proppant transport, hence an increased dune height that could lead to premature screenout at low pumping rates. A lower-density proppant would be easier to transport with unviscosified fluids such as completion brines, thus allowing the use of reduced pumping rates to circulate proppant at the bottom of the screen and pack the entire horizontal open hole successfully. Two types of ULWPs have been used for this purpose, one with a specific gravity of 1.25 and one with specific gravity ranging from 1.75 to 1.90 (ULWP-1.25 and ULWP-1.75, respectively). Well Configuration and Completion Most fields in the Campos and Espirito Santo basins are developed with a minimum number of wells, some being extended-reach wells. To reduce the number of casing strings, a slender-well design often is used. The horizontal open hole is drilled at 90° to final depth with an 8½- or 9½-in. bit and drill-in fluid. After the final horizontal extension is reached, the drill-in fluid is replaced with completion brine. Then, the completion assembly is run into the well. The completion equipment comprises an isolation packer and 13 Cr premium screens. The gravel-pack operation is performed with a special horizontal tool system that allows gravel packing and stimulation of the horizontal well in a single trip.

Modeling Horizontal-Completion Deformations in a Deepwater Unconsolidated-Sand Reservoir

Summary We present the development and results of geomechanical models and analyses used to assess the risks of compaction-induced deformation and potential failure of horizontal gravel-pack completions in a field located in deep water but at shallow depth below the seafloor. The target reservoir consisted of high-porosity, underconsolidated stacked turbidite sandstones, which are comparable to some of the more well-known, problematic compactive reservoir sands. The formations indicated a high level of risk of depletion- induced compaction, which could produce large deformations and potential failure of completion equipment in horizontal wells. Coupled poroelastoplastic geomechanical finite-element models were constructed to assess the risks of completion-equipment damage because of depletion-induced reservoir compaction. Both openhole and cased-hole gravel-packed completion configurations were analyzed. Details of the prepacked-screen assembly components were included in the models, such as the ribs between the base pipe and inner screen and the deformable epoxied sand between inner and outer screens. Model results presented in this paper include deformations of the completion equipment and stresses in the screen components, as a function of reservoir-depletion pressure. The results of the geomechanical modeling indicated that the overall compaction loading should not cause significant deformation of the specified completion equipment.

Successful Implementation of Horizontal Openhole Gravel Packing in the Stybarrow Field, Offshore Western Australia

Summary Key sandface completion challenges were faced in the selection, design, planning, and execution phases of the openhole horizontal gravel-pack completions in the deepwater Stybarrow field, offshore Western Australia. Only limited technical experience and infrastructure were available in the country to support such a complex operation. Additionally, the lateral reservoir-quality variations and challenging sand/shale heterogeneities have necessitated an early focus on appropriate reservoir-drilling-fluid (RDF) design, detailed sand-screen selection, and gravel-pack modeling to minimize premature screenout during gravel packing and to ensure minimal formation damage. This paper documents the multidisciplinary approach that commenced during the field-appraisal and data-acquisition stages to derive the sand-management plan and that culminated in the successful implementation of four horizontal openhole gravel packs. A novel RDF design, extensive formation-damage testing, and the selection of the circulating gravel-packing technique have led to the successful sand-control implementation, with pack factors in excess of 100%. Attention to detail during detailed design, extensive contingency planning, and diligent execution were major contributing factors in delivering high-quality wells capable of producing as per basis of well design, proved by early production performance. The Stybarrow development represents the first successful implementation of horizontal openhole gravel packing in Australia.

World's First Gravel-Packed Inflow-Control Completion

Summary The Etame oil field, offshore Gabon, West Africa, has been producing since September 2002. The Etame oil reservoir is an oval-shaped, low-relief structure with a moderate aquifer drive. To maximize ultimate field recovery, the ET-6H well was drilled with a horizontal lateral positioned to traverse the reservoir near the structural crest and to be within the Upper Gamba sandstone throughout its length. The Gamba sandstone averages 45 ft in thickness and overlies a significant angular unconformity. The subcropping Dentale-aged sandstones and interbedded shales below this unconformity have dips to 12°. The oil column of approximately 170 ft extends below this unconformity. Previous wells in the field were completed using openhole horizontal gravel packs (OHGPs) and have experienced excellent sand-control performance. However, OHGPs offer no protection against early water breakthrough. The Gamba sand averages 30% porosity with a permeability range of 1 to 3 darcies. The Dentale sands are much more variable, with porosities of 18 to 30% and a permeability range of 50 to 1,000 md. Thus, if a portion of the lateral is situated immediately above a high-permeability Dentale sand, the well will be at risk of early water breakthrough and subsequent reduced recovery if it is completed with a standard OHGP. The operator gravel packed the ET-6H well and used a system that provides a near-uniform inflow profile along the entire lateral length to protect against early water breakthrough. The gravel packing of inflow-control devices (ICDs) presented some unique challenges because of their differences from standard sandcontrol screens. This paper describes the implementation of the world's first gravel packed inflow-control completion, including: ICD selection process, gravel-pack design, data from the gravel-pack operation, and resulting well performance.

Overview: Well Stimulation (July 2007)

For this month's issue of featured well-stimulation papers, the ongoing work in acidizing earns my recognition as the most enlightening and yet overdue progress. Although the papers spotlighted in this issue are strong presentations on diverse subjects, I was most surprised by the volume of engaging papers focusing on acids and fracture acidizing. There are great papers in my list with information on horizontal wells, gravel packing, and viscoelastic fluids; however, each of these technologies is young compared to acidizing reservoir rock. In one of the additional-reading selections, "Fracture Acidizing: History, Present State, and Future," we learn that acidizing carbonates dates back to 1895. Therefore, the use of acids to increase production is more than a century old. With many of the modern acidizing theories developed around 1972 by Neirode and others, it is still a 35-year-old technology that needs a fresh look with modern methods. Whether we are studying etching behavior to forecast conductivity or predicting long-term reductions in performance caused by creep, we still have a lot to learn about this venerable practice. Therefore, the question becomes: "How can acidizing oil wells be more than 100 years old, yet we just now are beginning to unravel these fundamental concepts?" The world produces approximately 85 million BOPD, and assuming just USD 50/B, we generate more than USD 1.5 trillion/yr in world oil revenue. Whatever the historical disconnect has been between oil revenues and funding oil science, I am pleased to recommend these compelling technical papers on subjects vital to our industry, including the common practice of pumping acid into a formation to increase production. Well Stimulation additional reading available at the SPE eLibrary: www.spe.org SPE 108075 "Horizontal-Well Completion and Stimulation Techniques—A Review With Emphasis on Low-Permeability Carbonates" by Valdo Ferreira Rodrigues, SPE, Petroleo Brasileiro, et al. SPE 107772 "The Effects of Acid Contact Time and the Resulting Weakening of the Rock Surfaces on Acid-Fracture Conductivity" by M.G. Melendez, Texas A&M University, et al. SPE 107760 "Acid Stimulation of Extended-Reach Wells: Lessons Learnt From N'Kossa Field" by J.M. Mazel, Total, et al. SPE 106371 "Fracture Acidizing: History, Present State, and Future" by Leonard J. Kalfayan, SPE, BJ Services

Overview: Horizontal and Complex Trajectory Wells (November 2005)

Since the early 1980s, directional-drilling technology has become a vital tool for the drilling engineer. Supporting technologies such as the measurement-while-drilling, pressures-while-drilling, wire-line-steering-tool, and, as of late, rotary-steerable systems allow custom design of target intercepts. Directional-wellbore-profile types now include the build-and-hold, S-curve, horizontal, multi-lateral, radial drilling from a lateral, and “sump drilling,” which creates a “belly” or curved section vertically deeper than the reservoir total depth of the well. Sump drilling uses a pump in the belly portion to aid production and is specifically used for formations that contain heavy oil or that experience impeded formation feed-in. Regardless of which wellbore profile is chosen for development of the target reservoir(s), burning questions often go unanswered. How much target exposure is too much? How far should the lateral be extended before overextending the economic ability to recoup the investment? To answer these questions, mechanical aspects and production limits must be considered in addition to economic limits. The length of an extended-reach well may be limited by torque and drag or wellbore stability. The length of the lateral in a horizontal well in a 1-darcy-permeability sand may be production-tubing limited. The expense of drilling a 500-ft lateral in such a high-permeability sand may create the same production rate and ultimate recovery as a 1,500-ft lateral in the same target. Specific answers appear to be woven into the fabric of each directional application. Some parameters include matrix permeability, relative mobility of the produced hydrocarbon or water, wellbore stability, pressure drop from lateral toe to heel, production-tubing size, target pore pressure, anticipated depletion limits of the target formation, and existence of fractures or faults within the target. A thorough examination of all the appropriate factors may reveal a surprising truth: less exposure to the target may be better. Available from the SPE eLibrary: www.spe.org SPE 89848 “A Novel Approach to Production Logging in Multiphase Horizontal Wells,” by Vu-Hoang, D., SPE, Schlumberger, et al. SPE 92685 “U-Tube Wells—Connecting Horizontal Wells End to End Case Study: Installation and Well Construction of the World’s First U-Tube Well,” by Lee, D., SPE, Landmark Graphics Corp., et al. SPE 93986 “Evaluation of Two-Phase IPR Correlations for Horizontal Wells,” by Kamkom, R., Texas A&M U., et al. SPE 94945 “A Quantum Leap in Horizontal Gravel-Pack Technology,” by Mendez, A., SPE, BJ Services Co., et al. Available at the OTC Library: www.otcnet.org OTC 17548 “New Technology Applications To Extend Field Economic Life by Creating Uniform Flow Profiles in Horizontal Wells: Case Study and Technology Overview,” by Ratterman, E.E., Baker Oil Tools, et al.

A Mechanistic Model for Horizontal Gravel-Pack Displacement

SummaryThis article presents the detailed formulation for each of the three steps of a horizontal gravel-pack displacement operation, including sand injection and alpha/beta waves propagation. The main core of the model, aiming to define alpha wave height, is based on a well known two-layer model. Initially developed for hydrotransport applications, this kind of model has been adapted by several authors for drilled cuttings transport analysis. Additionally, a comparison between theoretical predictions and pumping charts from a field operation performed in Campos basin is presented.

Completion Tools Successful in Deepwater Frac Packs

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 74492, "Completion Tools Proven Successful in Deepwater Frac Packs and Horizontal Gravel Packing," by Leo E. Hill, SPE, Gene Ratterman, SPE, Perry Baycroft, SPE, and Anderson da Silva Amaral, Baker Oil Tools, originally presented at the 2002 IADC/SPE Drilling Conference, Dallas, 26-28 February.

Horizontal Drilling and Gravel Packing in Deep and Ultradeep Water

This article is a synopsis of paper SPE 67750, "Successful Horizontal Drilling and Gravel Packing in Deep and Ultradeep Water," by J.P. Vozniak, SPE, S.P. Mathis, SPE, W.C. Hogg, and E.E. Ratterman, Baker Oil Tools, originally presented at the 2001 SPE/IADC Drilling Conference, Amsterdam, 27 February-1 March.

Ram/Powell Deepwater Tension-Leg Platform: Horizontal-Well Design and Operational Experience

Summary A key focus of the Ram/Powell project is to utilize high-rate (>20,000 BOPD), high-volume wells (i.e., reserves several times greater than that of shelf wells) to enhance project profitability. Completions with large 5½-in. production tubing and horizontal openhole gravel packs (OHGP's) exceeding 2,000 ft in length have been implemented successfully. The horizontal OHGP design, the first implemented in the deepwater Gulf of Mexico (GOM), was selected as a means to improve well reliability over prior horizontal completion designs and sustain high production rates without plugging. A high rate of sand-control failure and plugging have plagued prior GOM horizontal non-gravel-packed completions. Achieving high-quality completions is a major project emphasis. Drilling, completion design, and operational experience of the horizontal wells are discussed. Production from the Ram/Powell tension-leg-platform (TLP) development, Shell's third TLP, began in September 1997. The TLP is located at Viosca Knoll Block 956 in 3,214 ft of water. Four wells were predrilled prior to TLP installation. Ten wells are completed. Five are horizontal OHGP's, one is a single-zone cased gravel pack, and the remainder are two- and three-zone-selective cased gravel-packed completions. Rig operations concluded in January 2000.

Horizontal Gravel-Packing Technique for Slim, Cased Holes in Highly Permeable Zones: A Single-Well Case History

Summary This paper describes a technique for horizontal gravel packing of slim, cased holes. The key to the technique is the use of horizontally oriented perforations as a means of providing self-diversion of the gravel pack regardless of fluid leakoff. Traditional horizontal gravel packing requires minimizing fluid leakoff to the formation; otherwise, premature bridging can occur during the gravel-packing process. The cased hole horizontal gravel-packing process presented here, however, does not require minimizing fluid leakoff to the formation, thus, allowing the possibility of placing a gravel pack in a horizontal casing with less resultant damage than is possible with traditional techniques. Gravel packing is becoming a common practice for controlling unconsolidated sands in horizontal wellbores. So far, horizontal gravel packing has been applied almost exclusively to open holes with screens in them. If a formation has a high permeability, and therefore, a high fluid-loss rate, placement of a gravel pack may be prevented by premature dehydration and bridging of the gravel-pack sand in the wellbore/screen annulus. The usual method of preventing these high fluid losses and the resultant bridging is to damage the formation face prior to gravel packing. The damage mechanism is usually salt, calcium carbonate, or other particles that seal off the formation face. Once gravel packing is completed, the formation damage is (hopefully) remediated using acid or undersaturated brines to restore the completion's productivity. There is, however, a risk that the damage cannot be successfully removed once it is gravel packed against the formation face. Acid diversion is also a problem when attempting to remediate damage in an openhole gravel-packed completion. This paper presents an alternative technique for performing a horizontal gravel pack in a high-permeability zone while reducing the risk of permanently damaging the formation's permeability. The technique involves cementing casing through the horizontal completion interval and then shooting perforations in a horizontal orientation. The perforations can then be acidized with better diversion techniques than is possible in an openhole completion. An uncentralized screen is then gravel packed. The horizontally positioned perforations provide a self-diverting gravel pack. The self-diverting nature of this technique makes it relatively insensitive to fluid loss; whereas openhole techniques are very sensitive to fluid loss. The uncentralized liner rests on the bottom of the horizontal to provide maximum standoff from the perforations. The above technique was applied at Thums Long Beach Company to a well with a 560-ft horizontal completion cased with a 412-in. liner (4.052-in. ID). The technique's acidizing phase, however, was not performed due to fishing concerns inside the slim liner. This paper presents a case history for gravel packing a 690-ft-long, 278-in.-slotted liner inside the horizontal 412-in. casing. To our knowledge, this is the slimmest horizontal gravel pack ever attempted. The gravel packing was performed successfully even though fluid returns were never established during the job. The lack of fluid returns is due to excessive fluid loss to the formation. The self-diverting nature of the horizontal perforations was the key to successful gravel packing. Production rates, on the other hand, were not as successful since we did not acidize the perforations prior to gravel packing. Comparisons between this well and openhole horizontal gravel packs are made.

Laboratory Modeling of Mudcake Application and Erosion for Gravel-Pack Design in Horizontal Wells

Summary Successful gravel packing of long horizontal sections depends in part on preventing carrier fluid from leaking off to the surrounding permeable reservoir. This requires correctly designed drill-in fluids to apply a thin filter cake, rendering impermeable the sand formation at the wellbore wall. Filter cake must be embedded sufficiently within the formation interstitial space to resist scouring by flowing sand during the gravel-packing operation. This paper summarizes testing using a large-scale laboratory apparatus and procedure designed to test the effectiveness of drill-in fluids planned for use in horizontal wells recently drilled in the Gulf of Mexico. This paper shows the benefits of modeling a horizontal gravel-pack interval before attempting to install the gravel pack. Gravel-packing techniques for long horizontal well sections were evaluated with a laboratory model of a casing/borehole annulus. In the horizontal section modeled, permeability is sufficient to interfere with the transportation and distribution of pack sand from total depth to dogleg when positive differential pressure is maintained. The goal of this modeling experiment was to predict whether the formation's permeability at the sandface could be reduced enough to allow successful gravel packing without damaging the formation far beyond the sandface. Gravel-packing technology is well established for near-vertical wells, with off-the-shelf equipment and textbook procedures readily available. The exceptionally long producing intervals in horizontal wells present a greater challenge for gravel packing, however, interval permeability is, by design, continuous. This continuous permeability both enhances well productivity and allows increased wellbore fluid flow into reservoir rock. When the permeable formation absorbs the fluid energy necessary to evenly disperse pack sand throughout the section, sand bridging can result, restricting the flow before the pack sand is fully distributed across the entire interval. The laboratory model simulates the axial flow of drilling and/or completion fluids through an annulus. The model has an impermeable confining wall (simulating the casing) and a permeable wall (simulating reservoir rock). Recently, it was used for testing the capacity of a drill-in fluid to reduce reservoir near-face permeability, and allow sand propagation throughout a long horizontal interval. Results obtained both in the laboratory and in subsequent field trials validate the use of a drill-in fluid in reducing near-sandface permeability. The procedure has been used successfully on multiple horizontal wells with typical horizontal section lengths of 1,000 to 2,500 ft. Plans are underway to continue the practice in additional wells.

Abstract: Horizontal gravel packing successfully moved to the deepwater floating rig environment

Abstract: Horizontal gravel packing successfully moved to the deepwater floating rig environment

Openhole Horizontal Gravel Pack From a Deepwater TLP

This article is a synopsis of paper SPE 50146, "New Completion Techniques Applied to a Deepwater Gulf of Mexico TLP Completion Successfully Gravel Pack an Openhole Horizontal Interval of 2,400 ft," by Pete Duhon, Alan Holley, Nick Gardiner, SPE, and Tommy Grigsby, SPE, Halliburton Energy Services Inc., originally presented at the 1998 SPE Asia Pacific Oil and Gas Conference and Exhibition, Perth, Australia, 12-14 October.

Gravel Placement in Horizontal Wells

Summary Long, horizontal gravel packs are viable completions that have been placed successfully in more than 80 wells. Extensive field-scale testing has significantly aided the development of field procedures and operating guidelines. Software has also been developed to assist with horizontal gravel-pack design. To be performed properly, these completions require a systems approach for their implementation because drilling and displacing the completion interval, maintaining hole stability, selecting and running equipment, and maintaining returns during the gravel-packing operation must be integrated into the completion strategy. Field experience suggests that, in some cases, gravel packs maintain productivity better than prepacked screens or slotted liners.

Alba Field Cased-Hole Horizontal Gravel Pack: A Team Approach to Design

Summary A 700-ft cased-hole horizontal well was gravel packed and completed in the Alba Field, central North Sea. The completion incorporated a number of new technologies adopted for a horizontal casedhole completion, including both equipment and fluids. The zone was completed in two stages using a horizontal stack-pack approach. Perforation packing was optimized by performing a staged acid prepack with the guns in the hole using a low-density synthetic gravel substitute in a shear thinning carrier fluid. This was a world-first achievement at a cased-hole gravel pack using the stack-pack approach in a horizontal well. A solids-free fluid-loss control material was evaluated and chosen for the high-permeability Alba sands (3 darcies). Extensive lab testing was performed to ensure minimal damage from various fluids. A 30-ft physical model was used to optimize annular pack efficiency. A gravel placement computer simulation was used to design pump rate, sand concentration, and gel loading to optimize annular and perforation-pack efficiency.