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. Shallow-water offshore production began before 1900 and continues to be important. Technology to maximize economic production from shallow-water fields can be adapted from onshore or deepwater technologies. Standalone-sand-screen (SAS) completion, especially in horizontal gas wells with high potential for sand production, typically suffers from premature failure caused by sand erosion resulting from high velocity in the annulus near the heel section.
Because of inherent complexities, understanding the characteristics of perforations in downhole environments is a significant challenge. Perforation-flow laboratories have been used to provide insight into cleanup and productivity mechanisms around perforation tunnels. Erosion caused by fine solid particles presents one of the greatest threats to oil and gas flow assurance, consequently affecting material selection and wall-thickness design.
This review of papers illustrates some of the innovative solutions used in the region. A look at techniques and technologies aimed at mitigating erosion issues from produced sand. Facilities sand management is tasked with the goal of ensuring sustained hydrocarbon production when particulate solids are present in well fluids, while minimizing the impact of the produced solids on surface equipment. This paper discusses the available methodologies for remediation of a pipeline affected by sand and presents examples where the discussed methodologies have been applied.
Controlled laboratory experiments and some field studies have shown that the onset of sand production in gas wells differs from that in oil wells. Results from a general 3D sand-production numerical model are presented to explain the differences in the onset of sanding and sand-production volume for different fluids and under different flow and in-situ stress conditions. The sand-production model accounts for multiphase-fluid flow and is fully coupled with an elasto-plastic geomechanical model. The sanding criterion considers both mechanical failure and sand erosion by fluid flow. Non-Darcy flow is implemented to account for the high flow rates. The drag forces on the sand grains are computed on the basis of the in-situ Reynolds number. Both the intact rock strength and the residual rock strength depend on water saturation. Water evaporation (drying) resulting from gas flow is modeled using phase equilibrium calculations.
The onset of sand production is compared for different fluid types (oil and gas). Model results are shown to be consistent with experimental observations reported in the literature. For example, the onset of sanding is observed at higher compressive stresses for gas wells as compared with oil wells. The primary mechanism for this is for the first time shown to be sand strengthening induced by evaporation of water. This effect is not observed in oil wells. The sand-production rate when non-Darcy effects are considered is lower than for Darcy flow. The reason for this is the lower fluid velocity (for the same drawdown) and, consequently, smaller drag forces on the failed sand grains. The effect of water breakthrough and water cut on sand production is studied from both mechanical and erosion perspectives. The model is shown to be capable of accurately predicting the onset of sanding and sand production induced by multiphase- and compressible-fluid flows, helping us to predict sanding issues in both oil and gas wells.
Zhu, Haiwen (University of Tulsa) | Zhu, Jianjun (University of Tulsa) | Zhou, Zulin (University of Tulsa) | Rutter, Risa (Baker Hughes, a GE company) | Forsberg, Michael (Baker Hughes, a GE company) | Gunter, Shawn (Baker Hughes, a GE company) | Zhang, Hong-Quan (University of Tulsa)
As one of the most widely used artificial lift methods, electrical submersible pumps (ESPs) have been improved gradually since the 1910s. However, its performance and run life are affected by many problems such as gas lock, high viscosity fluid, corrosion, and erosion. With the development of horizontal well drilling and multistage hydraulic fracturing, sand production from unconsolidated sandstone and proppant backflow often cause severe damage to ESPs resulting in reduced operating lifespan. Measuring wear in an ESP pump and monitoring performance degradation is not only very difficult in field cases, but also in experimental studies. The results are precious for understanding the wear mechanism inside an ESP as well as guiding the ESP design and simulation. At the same time, vibration and performance data can provide significant guidance to ESP failure diagnosis, which can potentially reduce the time and cost of well service and extend ESP run life.
Wear processes inside an ESP can be classified by different modes of mechanisms. Erosive wear can be observed in the primary flow channel of the impeller (rotor) and diffuser (stator). Particle strike shroud surfaces and the scratched material is flushed away by fluids. Various semi-mechanistic erosion equations are available to be coupled with Computational Fluid Dynamics (CFD) to predict the erosion in ESPs. In the secondary flow region, balance chamber and sealing rings, particles are presented between the stator and the rotating rotor. Therefore, abrasive wear is believed to dominate the wearing process. Unlike erosion, abrasion is more complicated and abrasion equations are highly depended on geometries, physical mechanism and load between particle and target surface. In this study, a sand wear test flow-loop is designed and constructed to investigate wear in ESPs. Performance degradation, Erosion pattern, abrasion rate, and stage vibration of an ESP were recorded in a 64-hour sandy flow test.
When producing hydrocarbons from an oil well, managing erosion of both surface and subsurface components caused by solids in the flow stream is critical to maintaining operations integrity in both land and offshore assets. Although component lifetime prediction has advanced in the past few decades, the prediction's accuracy remains a major oil and gas industry challenge. Current computational models only provide an initial erosion rate which is usually assumed constant until equipment failure. However, observed erosional rates vary as a function of time due to the geometrical changes caused by equipment material loss, which result in variations in solid particle impingement velocity [
This paper presents an implementation of an erosion dynamics model in ANSYS FLUENT, a commercial computational fluid dynamics (CFD) software, to capture the progression of transient erosion. The model has the capability to capture the effects of surfaces receding from erosion at each time interval. By dynamically adjusting these surfaces and recalculating the local flow conditions in the area, this method can predict new erosion rates for each time interval and achieve fully coupled geometry-flow-erosion interactions.
This new erosion dynamics model was validated against experimental data from both literature and physical testing, and was determined to have accurately captured the observed erosion trends over time in terms of location and magnitude. The model was then employed to study two real world applications: 1) in evaluating the erosion risk for a high-rate water injector, it predicted the evolution of damage to a coupler designed to connect different diameter pipes, and 2) in analyzing facility piping systems connected to an unconventional well, it predicted the transient erosion trend from proppant flowback, which allowed for pipe geometry optimization to increase in erosional life expectancy.
Riyanto, Latief (PETRONAS Carigali Sdn Bhd) | Sidek, Sulaiman (PETRONAS Carigali Sdn Bhd) | Hugonet, Vincent (PETRONAS Carigali Sdn Bhd) | Yusuf, M Hafizi (PETRONAS Carigali Sdn Bhd) | Salleh, Nurfarah Izwana (PETRONAS Carigali Sdn Bhd) | Ambrose, Jonathan Luke (SMS Oilfield)
Many oil and gas fields have long been suffering from sand production due to either the absence or failure of primary well sand control. To avoid mobilizing costly work-over rig to pull out the tubing, operators have tried various thru-tubing remedial sand control. The well's condition such as sands accumulation and space constraints due to small inner diameter of tubing always make this remedial job challenging. It is not surprising that the results are not all satisfactory.
Among the industry-recognized remedial sand control, Stand Alone Screen (SAS) is the simplest and the cheapest method. Many SAS have been installed but most were failed with screen erosion as the main failure mechanism. Flowing high velocity fluid with sands wears out the screen fast making it impossible for the sands to bridge and to create formation sand pack around the screen.
Ceramic Sand Screen (CSS) technology which was recently introduced to the industry aims to address this erosion issue. Having more than ten times hardness of stainless steel, sintered silicon carbide ceramic material in CSS offers superior resistance to wear. The pilot was conducted by installing CSS in three (3) selected wells with sand production history. While waiting for acoustic sand monitoring installation, the wells were put on production with the same choke size and regular manual samplings were conducted to monitor the sand production.
The acoustic sand monitoring campaign began in November 2017. Sands production was carefully monitored during the process to determine the final choke size at which the wells would continuously produce. In the middle of the campaign due to adverse weather conditions, all non-essential personnel had to be abruptly demobilised from the field leaving acoustic sensors hooked-up to the respective flow line. This gave opportunity to have unplanned extended sand monitoring window.
Loss of Primary Containment (LOPCs) occurred in two CSS wells not long after that. In one the choke body was heavily eroded and the other well had a punched hole at the first elbow of the flowline. These incidents prompted full investigation to be conducted. This included pulling out the installed CSS and performed tear down analysis. Acoustic sand monitoring that just happened to be available in one of the wells proved to be critical in understanding the CSS failure.
The paper presents briefly on the CSS pilot project, the chronology of events until the incident, sands production trend from the acoustic sand monitoring. Using all available information, the paper provides details analysis on CSS failure mechanism.
Many components used in completions are geometrically complex and machined to tight tolerances. Precisely measuring the internal profile dimensions of these items after installation is impossible using mechanical means such as calipers due to the sharp ID changes precluding good finger contact. This paper will discuss the use of a precision ultrasonic tool that allows accurate measurements to be taken without physical contact, and to detail a case study of inspecting a landing nipple profile.
Mechanical finger type caliper devices cannot measure internal diameters unless physically in contact with the surface and this is not possible at all times. An alternative to physical measurement is to reflect a projected beam of acoustic energy from the target and, knowing the speed of sound of the well fluid, calculate an ID measurement. Using a number of ultrasonic transducers allows beamforming techniques to precisely focus the sound to produce good resolution. The ultrasound tool uses a circumferentially arranged band of 288 sensors that operate in a phased array to determine accurate ID of even very complex profiles.
A landing nipple is a component that is designed for the installation of flow control devices in a well completion and comprises a seal area and a lock profile. The dimensions of these faces are very precisely controlled during manufacture because the device being installed, such a safety valve, must fit perfectly in order to provide a seal and mechanical attachment. If the lock profile, for example, becomes damaged or eroded than there is a chance of the safety valve being ejected from the nipple. The 288 transducer array of the ultrasound tool provides a circumferential spacing of 1.25° between measurements; ensuring even small defects can be detected. Following a laboratory test of a representative landing nipple under controlled conditions to verify the tool performance, a number of landing nipples were inspected in a field where erosion was suspected. The tool was able to accurately map the complex locking profile and to measure the dimensions to within a hundredth of an inch in each case, giving the operator confidence that the correct locks were being used to install the safety valves.
The unique properties of focused ultrasound allow the mapping and verification of even complex machined components while they are still downhole. With 288 circumferential readings, high resolution measurements are possible to an accuracy of a fraction of a millimetre raising the possibility of engineering a solution to a given problem rather than resorting to the expensive option of replacing the completion.
Figure 1—The impact of fracturing on perforations varies within a stage. Greater erosion occurs during fracturing of the four perforations in cluster 5 (heel side on top row) than in cluster 1 shown at bottom (toe side, bottom row). Fracturing leaves its mark on each of the perforations penetrating the steel casing. The array of perforations above (Figure 1) were eroded by water and sand surging through these entry holes, some more than others. Dave Cramer, senior engineering fellow for ConocoPhillips, said pictures shot after fracturing are full of telling details when combined with other diagnostics.