Paradigm Shift in the Development of the North Kuwait Fields

The Cretaceous (Albian) Upper Burgan Formation has been on production for circa 60 years in the Raudhatain and Sabiriyah fields in North Kuwait and significant resources remain. Key to an optimized development of this important reservoir is the introduction of Slant Well technology incorporating the use of sliding sleeve completions. The Upper Burgan Formation in the Raudhatain Field consists of four major sand dominated layers that comprise the main producing zones. These likely represent high stand deposits that formed during a progradation of the delta system across the region. Separating the sand layers are non-reservoir mudrocks that were deposited in marginal marine settings and act as baffles or barriers to fluid flow. In order to maximize production from the Upper Burgan, KOC has instigated the use of high angle slant well technology which allows greater reservoir contact at the well bore for each sand layer. As well, all four layers are in contact with the well bore thereby maximizing the oil drainage more efficiently. Vertical wells achieve the same result, but the difference being far greater reservoir contact with the four major layers has been successfully accomplished with the Slant well, and this has afforded higher production rates. The use of the Slant well however is selective and horizontal well application is still in use in both fields where good sand continuity in a specific layer has been interpreted. Currently the non-conventional wells make up approximately 25 percent of the producers in the Raudhatain Upper Burgan, the rest being vertical wells. Drilling the Slant well is a challenge primarily due to the long intervals of shale that are encountered between the sand layers. Shale sloughing is the major problem. The Upper Burgan is a mature reservoir with a weak edge water drive. Pressure depletion is a concern that is mitigated with the use of an active sea water and effluent water flood program that is now in place. The first Slant well to be drilled in the Upper Burgan was RA-000A. The well, located in the southern part of the Raudhatain Field was drilled to a depth of 9858 feet with an inclination of 80 degrees through the productive intervals. The well was drilled to the top of the Upper Burgan and a 7 inch casing was landed at this depth and cemented. The productive interval was drilled with a 6 1/8 inch hole size having a length of 850 feet. The well was then completed with a sliding sleeve ICD (Inflow Control Device). The ICD completion in the Slant well allows more uniform production from different regions of the well bore with less draw down. This will minimize the water coning effect. The sliding sleeve can be used to shut off water producing intervals during the life of this producer. The successes and challenges of this well are explored in this paper.

Although the technology of highly inclined and horizontal wells has recently progressed significantly, a reliable and practical formula to estimate the productivity of the well with respect to any angle of slant and anisotropy of permeability is still missing. This paper provides a method of estimation which fills the gap. The well pressure decline curves are generated by a semi-analytical in-house simulator. They lead to a geometrical pseudo skin factor which is matched for slanted wells with an analytically-derived equation. For horizontal wells, comparison is made with several existing formulae. An unrestrictive approach of anisotropy is possible through a spatial transformation from real medium into equivalent isotropic medium : this is achieved by modifying the length, azimuth, inclination and radius of the well. Equations of the pseudo skin factor are modified according to this transformation. Calculations reveal that a slanted well is less affected by anisotropy than a horizontal well : with a low vertical permeability, it can be more advantageous than a horizontal well of the same length. Graphic charts are displayed to easy the choice between horizontal and highly inclined wells.

Raudhatain field located in North Kuwait produces hydrocarbons from over 230 wells into Gathering Center X with varying complex geometries, completions and downhole equipment. NK asset team is executing a project of modeling the entire NK production system starting with wells in Raudhatain field producing to GC-X, involving building models for the wells and the gathering surface network of flow lines. There are numerous challenges that the NK asset team is facing in meeting production targets, including controlling water/gas breakthrough in horizontal wells. Mitigation measures include installation of inflow control devices (ICDs). Since inception a decade ago this proven technology has long been used in many oilfields around the world and is increasingly being installed in horizontal wells in Kuwait. To date there are several horizontal wells in Raudhatain field completed with ICDs. Reservoir modeling and simulation approach is frequently used in the industry capturing the behavior of existing ICD wells. This approach uses conventional modeling tools that are typically more intricate and require expert skills in capturing the dynamic behavior of the wellbore and the reservoir which is less appealing to the operations and practicing engineers. Limited with time and resources in this project, the NK team took a relatively simpler and fast approach in modeling existing ICD wells in Raudhatain field with the aim of enabling the engineers to capture the behaviour of the wells using existing production engineering tools at their disposal. The approach can be summarized as follows: ➢Establishing the well performance➢Modeling the individual ICD sections in accordance to the approximate flow distribution/geometry along the horizontal well➢Matching the well with well test data Key benefits of this approach are: ➢Enabling the engineers to quickly model the ICD wells.➢Facilitated the use of existing tools to deliver engineering models fit for use in the production system.➢Serves the purpose of high level modeling of complex ICD wells and in the future this exercise will certainly be undertaken to capture wellbore hydraulic effects.➢ICD well models are timely added into the gathering network which would otherwise have been delayed using a conventional method.

Abstract. Conventional models of pumping tests in unconfined aquifers often neglect the unsaturated flow process. This study concerns the coupled unsaturated–saturated flow process induced by vertical, horizontal, and slant wells positioned in an unconfined aquifer. A mathematical model is established with special consideration of the coupled unsaturated–saturated flow process and the well orientation. Groundwater flow in the saturated zone is described by a three-dimensional governing equation and a linearized three-dimensional Richards' equation in the unsaturated zone. A solution in the Laplace domain is derived by the Laplace–finite-Fourier-transform and the method of separation of variables, and the semi-analytical solutions are obtained using a numerical inverse Laplace method. The solution is verified by a finite-element numerical model. It is found that the effects of the unsaturated zone on the drawdown of a pumping test exist at any angle of inclination of the pumping well, and this impact is more significant in the case of a horizontal well. The effects of the unsaturated zone on the drawdown are independent of the length of the horizontal well screen. The vertical well leads to the largest water volume drained from the unsaturated zone (W) during the early pumping time, and the effects of the well orientation on W values become insignificant at the later time. The screen length of the horizontal well does not affect W for the whole pumping period. The proposed solutions are useful for the parameter identification of pumping tests with a general well orientation (vertical, horizontal, and slant) in unconfined aquifers affected from above by the unsaturated flow process.

Rubiales and Quifa are the Colombia's major heavy oilfields (oil gravity ranges from 11.3 to 14.4° API) with a current oil production of more than 260 MSTB with an oil viscosity ranges from 370 to 730 centipoises. Horizontal well technology is used to drill through unconsolidated sandstones with an active and strong aquifer, under primary depletion. Since 2006, 604 horizontal producer wells have been drilled and completed using slotted liner in open hole. The high water production rate from the beginning of the operation in the horizontal wells is the main problem to be controlled in the Rubiales and Quifa fields, due to the high cost of produced water treatment and other factors. Water production is inevitably associated with the oil production; however one of the biggest challenges is to delay the water production as much longer as possible. Rubiales and Quifa actually have a large number of closed wells that have reached its economic limits, mainly by high water production. This production imbalance is being addressed in the new horizontal wells, using inflow control devices (ICDs). The ICDs is placed in each screen joint to balance the production influx profile across the entire lateral length and compensate the permeability variation and therefore the productivity of each zone. In 2012, a pilot test has been designed and implemented in Rubiales field with three horizontal wells using passive ICDs completion. The performance of the ICD's is found to reach the highest cumulative oil production compared to neighboring wells. The main purpose of this paper is to detail the selection process design and results evaluation for the use of the passive ICDs in horizontal wells at Rubiales and Quifa Fields, heavy oil reservoirs.

The Provost Dina 'X' Pool is a turbidite sand with a pay zone of up to 20 m at a depth of 200 mSS. The field contains approximately 1.2 million m3 of oil and there is a bottom water aquifer with partial pressure support in parts of the field. Most of the vertical wells in the field shut-in due to high water cuts after a relatively short period of production. Therefore, a numerical simulation study of the whole field was undertaken in order to improve recovery by infill drilling as well as by investigating different operating strategies. This paper describes the integrated team approach taken with input from the geological, production and reservoir engineering specialists to construct a reservoir model. The model has been successfully history matched and used, in turn, for predicting the performance of the field under existing conditions as well as a variety of infill drilling and operating scenarios. Results indicate that significant water coning, which would be observed with new vertical wells in certain areas of the pool, can be reduced through horizontal infill wells. Despite the potential technical success of horizontal infill wells, they were not economically feasible in this particular reservoir and vertical infill wells were the preferred choice. It is shown that a combination of carefully planned vertical infill wells and a pressure maintenance program is able to boost the ultimate recovery by 34% while keeping the development costs to a minimum. Results of various operating strategies are presented and the optimum field development scenario implemented in the field is outlined. The initial actual reservoir behaviour is discussed in the light of the results from the simulation study. Introduction The Provost Dina 'X' pool was discovered in 1988 at an initial pressure of 6450 kPa. The reservoir is located in east central Alberta, south of the town of Consort. The formation is a turbidite sand with a limited bottom water aquifer support. The production from the pool began with the discovery well 05-15-35-06 W4M and, to date, a total of 11 wells have delineated a reservoir area of slightly more than 32 ha. (see Figure 1). Historically, most of the vertical wells in the field experience high water cuts after a relatively short period of production. Thus, a significant portion of the reserves cannot be produced because of water coning. Infill drilling can compete favourably with BOR processes for the recovery of the bypassed oil for much less investment and operating cost. As the existing vertical wells have to be operated above the critical water coning rates to be economic, horizontal wells become another option for infill drilling. The field experience indicates that horizontal wells can reduce the water coning tendency while increasing the oil production. However, further improvement to oil production rate of horizontal wells is still limited by the encroachment of the water cone when the bottom water exists. Therefore a simulation study was undertaken to investigate the feasibility of increasing reserves by infill drilling with horizontal and vertical wells. Model Construction The black oil simulation module (SimBest II) of The Petroleum WorkBench reservoir management package of Scientific Software-Intercomp was used to conduct this simulation study. SimBest II is a three-dimensional, fully implicit reservoir simulator which is capable of handling as many as three fluid phases and five components in a dual and/or single porosity mode. P. 555

Horizontal wells are well-recognized as one of the most effective innovations in exposing the wellbore to maximum reservoir contact and drainage area to improve recovery economics. It creates lower pressure drop to achieve better productivity compared to vertical/deviated wells. In order to enhance sweep efficiency, horizontal wells can be completed with Inflow Control Devices (ICD). ICD completion creates a more uniform inflow distribution along the production interval of the horizontal well. It aims to delay water breakthrough at high permeability zones and to provide better well clean up at initial production. In general, the performance evaluation shows that horizontal wells with ICD's have better sustained productivity than horizontal wells completed open hole or with screens. ICD completion design was previously done based on near-wellbore data only. A new methodology has been applied by tailoring the ICD completion design with fine-grid dynamic 3D simulation that is fast enough to be used for real-time model optimisation while drilling. 3D simulation enables the optimisation for the number and placement of nozzles and packers by maximising the utilisation of reservoir information. The improvement on delivering ICD completion design also includes torque and drag analysis on every horizontal well candidate. The new ICD completion design workflow has been applied since 2015. The real-time single-well dynamic 3D simulation-based design results in a better understanding of the completion options and their performance predictions. Various ICD completion scenarios, from constant nozzle sizes to varying nozzle sizes, and different packer numbers and placements are simulated. The new 3D simulation tool is able to provide time-lapse effects of cumulative fluid (oil and water) production for different flow rates. Additional pressure drop across the completion is modelled for different nozzle configurations. Based on these simulation results better informed decisions can be made regarding the nozzle sizes and numbers. In addition, the proposed ICD completion run-in-hole tally is evaluated in the torque and drag simulator to ensure the proposed ICD completions can be run to total depth (TD). The results of these two simulation steps are combined to optimize the final ICD completion design.

Horizontal well completions are often equipped with Inflow Control Devices (ICDs) to optimize flow rates across the completion for the whole length of the interval and to increase the oil recovery. The ICD technology has become useful method of optimizing production from horizontal wells in a wide range of applications. It has proved to be beneficial in horizontal water injectors and steam assisted gravity drainage wells. Traditionally the challenges related to early gas or water breakthrough were dealt with complex and costly workover/intervention operations. ICD manipulation used to be done with down-hole tractor conveyed using an electric line (e-line) cable or by utilization of a conventional coiled tubing (CT) string. Wellbore profile, high doglegs, tubular ID, drag and buoyancy forces added limitations to the e-line interventions even with the use of tractor. Utilization of conventional CT string supplement the uncertainties during shifting operations by not having the assurance of accurate depth and forces applied downhole. A field in Saudi Arabia is completed with open-hole packer with ICD completion system. The excessive production from the wells resulted in increase of water cut, hence ICD's shifting was required. As operations become more complex due to fact that there was no mean to assure that ICD is shifted as needed, it was imperative to find ways to maximize both assurance and quality performance. In this particular case, several ICD manipulating jobs were conducted in the horizontal wells. A 2-7/8-in intelligent coiled tubing (ICT) system was used to optimize the well intervention performance by providing downhole real-time feedback. The indication for the correct ICD shifting was confirmed by Casing Collar Locator (CCL) and Tension & Compression signatures. This paper will present the ICT system consists of a customized bottom-hole assembly (BHA) that transmits Tension, compression, differential pressure, temperature and casing collar locator data instantaneously to the surface via a nonintrusive tube wire installed inside the coiled tubing. The main advantages of the ICT system in this operation were: monitoring the downhole force on the shifting tool while performing ICD manipulation, differential pressure, and accurately determining depth from the casing collar locator. Based on the known estimated optimum working ranges for ICD shifting and having access to real-time downhole data, the operator could decide that required force was transmitted to BHA. This bring about saving job time while finding sleeves, efficient open and close of ICD via applying required Weight on Bit (WOB) and even providing a mean to identify ICD that had debris accumulation. The experience acquired using this method in the successful operation in Saudi Arabia yielded recommendations for future similar operations.

High water production is a major issue in horizontal oil wells, especially in longer laterals, because of the high drawdown from the heel to toe. In addition, the presence of heterogeneity along the lateral section can lead to uneven sweep of hydrocarbons which can result in poor recovery. To control the water production and achieve better sweep efficiency, ICDs have been introduced which balance fluid flux along the producing horizontal well. This paper discusses the feasibility and results of using integrated technologies such as ICDs along with rotary steerable drilling systems (RSS) and azimuthal logging while drilling well placement technology to achieve higher reservoir sweep efficiency. This case study is focused on a Gulf of Mexico (GoM) shelf horizontal well which was completed with prepacked screens. The well was sanded in and plugged after five years of high water production. A saturation log was run in the offset well which granted the viability to revisit this reservoir. Consequently, a new offset horizontal well was proposed and drilled next to the existing well to sweep out remaining reserves. For the new offset well, full field dynamic simulations were performed to evaluate attic placement methodology and optimization of Inflow Control Devices (ICDs) into the integrated design. The results illustrate that attic horizontal well placement is feasible using integrated drilling with ICD technology to maximize the sweep efficiency.

The objective of this paper is to present learnings from designing inflow control devices (ICD) of numerous wells at reservoirs with gas cap with various settings. Key aspects and an efficient ICD design workflow will be presented. The evaluation is based on the application of nozzle ICD for single lateral horizontal well. A synthetic simulation model is utilized to demonstrate example cases. A horizontal well installed with ICD completions improves well performance by equalizing production along the horizontal section to delay water/ gas breakthrough for an oil reservoir with gas cap and aquifer. We utilized an in-house reservoir simulator with advanced complex well options. The first step is to develop an ICD completion design workflow, which includes understanding reservoir permeability heterogeneity, its magnitude and well flow behavior under open-hole completion. At well level, this step is to estimate future major gas and water contribution. Optimum well rate is sensitized for the ICD design. The next step is to focus on ICD design optimization which includes numbers of ICD requirements and compartments, ICD choking. The performance of horizontal well placed under a gas cap was analyzed. An early gas production easily occurs especially for well with high production rate. Controlling gas and water production showed an improvement on oil recovery. We developed the workflow of an ICD completion design optimization for the evaluation. Simulation model with different reservoir properties vertically were created for ICD design case. The ICD design optimization cases with combination of these two factors are evaluated to identify conditions for ICD installation that provide best benefits. Results showed that installation of ICD provides good performance improvement and more even gas oil contact and water oil contact movement toward the wellbore. The ICD design workflow provides a guideline to do the ICD design systematically utilizing reservoir simulation model for an oil rim reservoir. Learnings obtained from the results provide an understanding on the optimal conditions for ICD installation with the goal to ultimately deliver long-life wells while controlling water and gas production in different levels of reservoir heterogeneity and well lengths.

The first horizontal oil well was drilled through an anticline structure in the Block-7E of East Flank, S-field, penetrating three production sands Sand I, Sand II and Sand III. Based on a comprehensive pre-drill study through steady-state and 3D dynamic time lapse simulation, Inflow Control Device (ICD) with integral sleeve (on/off function) attached to the ICD's joint is the optimum development of the fault block that maximizes zonal control for contrasting water encroachments. Due to the unconsolidated nature of the target reservoir, this well is designed for Open-Hole Gravel Pack (OHGP) with specialty 3D filtration screen to manage sanding issue. This paper highlights 2-in-1 application of ICD with enabled zonal shut-off sleeves and the OHGP completions with external screen. A pre-drilled ICD dynamic modeling is constructed to evaluate the well performance with ICD configuration. The design criteria for an optimum ICD design configuration is based on number of compartments and size, packer placement, ICD nozzle sizes and numbers. This dynamic single well model was used to justify the technology value which resulted in production improvement (maximizing oil and minimizing/delaying water). However, during the drilling of this well, the pre-drilled model is then updated in real time with the input of actual petrophysical data from Logging While Drilling (LWD) measurements along the OH section. Actual well trajectory and structure adjustment encountered while drilling were also co-utilized to determine the final optimum ICD design for the field run-in-hole (RIH) completion. Target fault block in S-Field East Flank requires optimum development strategy for its economic viability (Kumaran, P. N et al. 2017). Only one open-sea discovery well proved the oil bearing sands to-date, but a lot of uncertainties remains: geological structure, fluid contacts, fluid characterization, existence and nature of an aquifer, etc. Hence, all these uncertainties are incorporated in the ICD optimization through sensitivity analysis and uncertainty range estimation. Oil production improvement with water reduction while delaying water encroachment are key in the optimization of the ICD design, which is achieved by evaluating the impact of ICD's influx balancing throughout the horizontal section. Study shows that water encroachment is effectively controlled with 9 compartmentalization zones along the horizontal section, each one separated using oil swellable packer. After 7 months of stable flow, well test is showing zero-water and zero-sanding to surface with well controlled production rate that can produce more if required. This is the testimonial of the deployment success from its initial conceptual design to its ultimate completion.

Horizontal and drainhole drilling have been used successfully to increase productivity of wells in the past years. Many formulae can be used to compute the productivity of horizontal or slanted wells compared to vertical ones. One objective of this work is to recall the proper way to use these formulae and to recall the assumptions made that may limit their use. The increase of productivity due to longer perforated interval increases as the logarithm of length and can reach values of two or three times the vertical well. Also presented is a sample calculation of the influence of natural or artificial fractures on well productivity: a horizontal well may take advantage from an existing fracture network, much better than a vertical well would have. This is because the most permeable fractures are the open ones which have their planes parallel to the largest stress, and the largest stress is generally vertical because of rock weight. The productivity of a drainhole in a fractured medium can raise to 10 times the productivity of the drainhole alone. Another improvement expected from horizontal wells is a larger flexibility regarding coning problems: it is possible to produce with an interface while keeping a good productivity and a high critical rate. The analytical means for critical rate computation are reviewed with their assumptions. Model computations give the examples of supercritical production in the bottom water drive case. The advantage of horizontal well is important at water breakthrough but does not increase much after and even decreases for favorable mobility ratios. Short drainholes may perform as well as horizontal wells if their distance allows a large interference of cones. The third way of using horizontal wells is to increase areal sweep efficiency in regular pattern floods. The pattern showing the poorest efficiency is the direct line drive. Using horizontal wells drilled along the lines of producers can bring the areal sweep efficiency close to perfection. In that particular use, horizontal wells act like artificial fractures, with the advantage that their orientation can be controlled.

Horizontal wells drilled in heterogeneous reservoirs present several challenges for reservoir management. Issues like early water breakthrough and inefficient drainage around the well in a reservoir with high contrast in permeability are very common in horizontal wells. An effective approach to address the challenges of horizontal wells and to increase the oil recovery is to complete the wells with inflow control device (ICD) technology. Most ICD technologies available in the market are passive inflow control devices that do not have the ability to change properties when unwanted fluids break through. The new ICD not only incorporates the benefits of passive ICD technology, it also incorporates sliding sleeves in the module that can be closed whenever the ICD starts producing water. This helps maximize the oil production from the well and reduces the problems related to handling of water at the surface facilities. This paper will demonstrate the effectiveness of the new hybrid ICD design. It is novel viscosity insensitive and may provide higher restriction to water over oil, and the successful operation of the sliding sleeve feature through a field case of a well drilled in a carbonate field in Middle East. Bottomhole pressure and weight indication observed through specialized fiber optic-installed coiled tubing confirmed the operability of technology by proper opening and closing of sliding sleeve. A fluid flow profile recorded by a production logging tool (PLT) on the same CT proved that the completion effectively equalized flow along the wellbore and will delay eventual water breakthrough while still producing at the desired production rates. PLT proved that the custom-designed completion with its appropriate number of compartments, number of ICD joints and flow resistance rating, achieved an optimized ICD completion.

In the oil and gas industry, the extraction process's success heavily depends on the efficiency and accuracy of the drilling phase. Despite being refined over several decades, traditional drilling practices continue to grapple with multiple challenges, often leading to inefficiencies, excessive costs, and high-risk scenarios. Historically, these challenges have predominantly stemmed from the complex nature of the subsurface environment. Varying geological conditions, unpredictable physical properties, and ever-changing drilling dynamics constantly challenge operators worldwide. Given these challenges, the oil and gas industry has always been a fertile ground for innovation and technological advancements. Over the years, the industry has embraced various technological solutions to streamline operations, enhance efficiency, and ensure worker safety. However, in recent years, the rapid emergence of digital technologies, particularly Artificial Intelligence (AI) and autonomous systems, has provided the industry with unprecedented opportunities to revolutionize drilling operations. AI offers powerful capabilities for data processing, making accurate predictions, and optimizing complex systems, which are particularly beneficial in the intricate and data-intensive realm of drilling operations. On the other hand, autonomous systems promise to reduce human intervention in the drilling process drastically. This is highly significant, as human error has been identified as a leading cause of operational inefficiencies and safety incidents in the oil and gas industry. In this context, implementing AI-driven autonomous solutions marks a transformative phase in drilling operations. These solutions can potentially revolutionize drilling operations, promising to drive significant improvements in drilling efficiency, operational costs, and safety measures. Against this backdrop, Kuwait Oil Company (KOC) has taken a pioneering step by implementing the first Neuro Autonomous Solutions in their operations in North Kuwait. This suite of solutions - DrillOps Automate, DD Advisor, and AutoCurve, are coupled with the SLB Well Construction Rig & Blue BHA to form an integrated, AI-driven, and autonomous drilling system. North Kuwait presents a particularly challenging drilling environment. Its unique geophysical characteristics and complex stratigraphy often cause operational inefficiencies and high drilling costs. Unpredictable subsurface conditions and highly variable drilling dynamics further compound these challenges. Implementing Neuro Autonomous Solutions in this region is thus a significant step forward, demonstrating their effectiveness in challenging conditions and paving the way for broader applications. The successful deployment of these solutions not only represents a significant achievement for KOC but also holds the potential to impact the broader drilling industry significantly. By showcasing how AI and autonomous systems can be harnessed to enhance efficiency, reduce costs, and improve safety, KOC's experience provides a blueprint for the industry to follow. Moreover, this development aligns with KOC's broader vision of embracing digital transformation. By leveraging innovative digital technologies, KOC aims to redefine its operational practices, particularly in drilling operations, to ensure greater efficiency, cost-effectiveness, and safety. Introducing these innovative digital technologies could signify a watershed moment for the drilling industry. It could spearhead a new era of digitally enhanced, efficient, and safe drilling operations if replicated across different operational contexts. In conclusion, this paper aims to present a detailed account of KOC's pioneering journey in implementing Neuro Autonomous Solutions. It strives to provide an in-depth understanding of these solutions, their operational implications, and their potential to revolutionize the drilling industry. Through this exploration, the paper seeks to contribute to the broader discourse on the role of digital technologies in driving transformation in the oil and gas industry.

The purpose of this paper is to report on the field test results of the Texaco Canada Petroleum Inc. (TEXCAN) and the Alberta Department of Energy (ADOE, formally AOSTRA), Electrical Horizontal Well Project in the Lloydminster heavy oil area. Two vertical wells (15D-25-56-2W4 and 13C-30-56-1W4) and one horizontal well (16D-25-56-2W4) were connected electrically and heated. This paper presents an overview of electrically heating a horizontal well with vertical wells, the design of the electrical heating system, operational experience, test data, and a discussion on the successes and problems of the project. Three wells were electrically heated; two deviated vertical wells and one horizontal well. The pilot project experienced premature equipment failure and sand production problems. Although a significant production response was achieved at the vertical wells, ongoing operations were not achieved because of sanding problems. The sand problem required daily workovers on the wells to maintain operations. As a result of these problems, and the limited current that can be supplied from just two vertical wells, the thermal response at the horizontal well was 3 - 5 °C and no production response was observed. The project was a technical success in that electrical current from two vertical wells was returned to the power conditioning units via the horizontal well and a thermal response was observed at all the wells. At the vertical wells, there was at times a greater than three times productivity response during electrical heating operations. Introduction Horizontal Wells and Heavy Oil Horizontal wells, typically 500 m in length and longer, are common in the exploitation of heavy oil reservoirs around the world. Horizontal wells offer prospects of improved performance over vertical wells, primarily due to the larger contact area between the formation and the wellbore. Also, the technology for drilling a horizontal well is as advanced as for drilling a vertical well. The cost of drilling a horizontal well is about the same as the cost to drill two to three vertical wells. There are production disadvantages and problems that are unique to a horizontal well application in heavy oil reservoirs. The production rate declines very rapidly during the first several months of production. It is also possible that the entire length of the horizontal well may not be productive. In some production systems, the limiting factor in producing the oil is the mechanical limitation of the pumping equipment, which is exceeded because of the very high viscosity of the oil. Finally, there may be skin effects, such as the visco-skin(1) that may further reduce the productivity of the well. This skin effect and other thermally alterable skin effects (for example, asphaltene precipitation) can block flow into the well, thereby decreasing the effective length and productivity of the well. Increasing the effective length of the well and removing any skin effects can improve the productivity of the well. Electrical Heating Electrical heating of vertical wells has been attempted on several occasions with encouraging results(2-10). Until now, there have been no electrical heating tests that use horizontal wells.