Underbalanced coiled tubing drilling (UBCTD) is one of the keys to unlock the true potential of the tight and abrasive sandstone.
The sandstone formation is mainly characterized by hard and abrasive sandstones interbedded with shale and siltstone. Typically, the sandstone formations are encountered at very deep depths. They are the most difficult sandstone formations to drill, with rock unconfined compressive strength (UCS) of up to 35,000 psi and internal friction angles ranging from 25 to 60 degrees. These conditions make it very difficult to drill and reach optimal lateral lengths. Additionally, it is very difficult to perform an openhole sidetrack (OHST) in such hard and abrasive formations, compared to more porous carbonates.
This paper will cover some of the key steps in optimizing underbalanced coiled tubing drilling in hard sandstones from different aspects such as drilling challenging profiles at high build rates, optimizing the rate of penetration (ROP), and also increasing formation contact by successfully performing OHST to deliver multiple laterals. The paper covers the following topics:
Optimizations in well design for lowest tortuosity and best wellbore access
ROP optimization and reducing well delivery time
Optimal combination of turbodrills, polycrystalline diamond compact (PDC) bits and optimized drilling practices
Improvements in PDC bit design for improved ROP and longer run length
Optimization of openhole sidetracks procedures
The combination of technology and process has so far resulted in successful delivery of many sandstone wells with multiple laterals drilled on most of the wells, totalling more than 35000 ft in this hard and abrasive formation. The first-time success rate of openhole sidetracks was 96%. The average ROP and bit run lengths have also improved consistently.
It is expected that the recent improvements and consistency in delivering the sandstone UBCTD wells, will enable engineers to expand the horizon of UBCTD to several other fields, and tap the true potential of sandstone formations.
Radial jet drilling, RJD is an unconventional drilling technique that uses the jet energy of high velocity fluids to drill laterals with different geometries in both conventional and unconventional reservoirs. Many case studies are available worldwide have proven RJD as a viable alternative to traditional stimulation techniques, especially in marginal fields. RJD has a lot of application in the oil and gas industry. It is a cost effective completion technique to reach the untapped sweet spots, by-pass damaged zones near wellbore, re-complete old wells, etc.
The present paper outlines the basics of newly developed radial jet drilling technology. Advances in technologies, developments, forces imposed, jet fluid hydraulics, procedures, applications, and challenges of RJD are reviewed in this paper. Simulation studies and several worldwide case studies are discussed to evaluate the RJD technology.
A significant percentage of all ESP failures are electrical failures and this becomes even more noteworthy in harsh, high temperature applications such as Steam Assisted Gravity Drainage (SAGD). For this reason, it is extremely important to continue the enhancement of ESP motor technologies that are specifically designed to address the challenging and unique SAGD environments that include wide bottom hole temperature ranges, abrasives and gas rich fluids. Through experience and testing, it has been learned that for these types of applications it imperative to design not only to a high temperature limit, but also to withstand extreme temperature cycles experienced on steam injection facility shutdown.
A combination of historic evidence with controlled laboratory evidence yielded improvement areas for a new high-temperature ESP motor development. The new high ultra-temperature motor breaks paradigms and opens a new generation of motors that looks towards above 300°C downhole temperatures. This paper will review the performance of the motor at Suncor's Firebag SAGD field where 92 units have been installed since January 2015 in bottom hole (BHT) temperatures reaching 240°C. Description of the laboratory qualification, major design characteristics and field results will also be discussed on the paper.
This paper focuses on the ‘High Fidelity’ (HiFi) simulation of process transients relevant to multiple turbo-compression trains in pipeline gas-boosting applications – parallel operation of Centrifugal Compressors (CC's) driven by Gas Turbine (GT's).
The ‘HiFi’ dynamic simulation concept is developed around the needs of an actual gas-boosting plant; specific reference is therefore made to the peculiarities of a facility located in the Middle East. Single/multiple train simulations are addressed, with a description of the main goals/assumptions and of the main advantages (vs. ‘Basic’ and ‘Advanced’ simulations) in terms of train performances verification and control software debugging/optimization.
Finally, the usage of cloud-based industrial-internet solutions for connecting dynamic simulation models running on dedicated, distributed platforms is also presented.
Supercritical CO2 (sc-CO2) miscible flooding has been successfully used as an enhanced oil recovery (EOR) method in both sandstone and carbonate reservoirs. The sc-CO2 is miscible with the remaining oil left after water flooding at injection pressures above MMP to achieve higher recoveries. During the process of the sc-CO2 injection after water flooding, there are two phases in the formation, a water phase and a miscible phase (sc-CO2dissolve into oil). To describe the flow characteristics and performance of these phase, the water (Krw) and miscible phase (Krm) relative permeability curves are needed in reservoir numerical simulation during sc-CO2 miscible injection. Surprisingly, publications of experimental data that include water and miscible phase are relatively rare due to the lack of proper experimental methods used. Usually, researchers use water and sc-CO2 relative permeability curves instead of water and miscible phase relative permeability to describe the flow characteristics when sc-CO2 displaces water and remaining oil. In this paper, we propose a modified method based on Corey's model to describe water and miscible phase relative permeability using end point values of water and sc-CO2 miscible flooding.
To obtain the end point values from water and sc-CO2 miscible flooding, four core flooding experiments were carried out on carbonate composite cores using live oil at reservoir conditions. These included two short core and two long cores. The Corey's model was used directly to predict oil/water relative permeability in the carbonate composite cores. A modified Corey model (proposed in this paper) was used to calculate water and miscible phase relative permeability and describe the flow behavior of sc-CO2. The effect of the Corey's exponents, Nw and Nm, were evaluated on relative permeability characteristics in the carbonate composite cores during sc-CO2miscible flooding.
Modified Corey model paramaters include the maximum water saturation, Sw(max), remaining oil saturation Sorw and Krw at Sorw from water flooding process, residual water and oil saturations and the maximum sc-CO2saturation from sc-CO2 injection process. The relationship between relative permeability to water and miscible phase vs. miscible saturation has been developed when the water saturation is decreasing during sc-CO2 miscible injection process. In addition, it is an obvious influence of water and miscible phase relative permeability when the Corey exponents, Nw and Nm are changed.
Wattanasuwankorn, Reawat (Halliburton) | Kritsanamontri, Panyawadee (Halliburton) | Limniyakul, Vorasak (Halliburton) | Sompopsart, Suwin (PTT Exploration and Production Limited) | Toempromraj, Wararit (PTT Exploration and Production Limited) | Kaenmee, Kwanjai (PTT Exploration and Production Limited) | Sa-nguanphon, Saksit (PTT Exploration and Production Limited) | Prasittisarn, Puchong IntasaloYotsak (PTT Exploration and Production Limited) | Sirisawadwattana, Jutaratt (PTT Exploration and Production Limited) | Vattanapornpirom, Kanda (PTT Exploration and Production Limited) | Boonyasaknanon, Phathompat (PTT Exploration and Production Limited) | Kongdachudomkul, Chatchai (PTT Exploration and Production Limited)
Low-permeability sandstone formations in deviated exploration wells were drilled and completed in 2013 in northeast Thailand. Reservoir simulation modeling indicated that a well would not produce as a result of the tight formation. Hydraulic fracturing was then considered, and a plan was adopted to use this method to improve the well's production using reservoir simulations. Microseismic fracture monitoring was implemented to correlate data with actual fracture propagation to understand the formation's geomechanics.
The fracture design methods were combined with completion and cleanout strategies to help improve well performance. The fracturing design was incorporated into a complete operational procedure, along with contingency plans, a decision tree, and an integrated communication plan, to allow for possible contingencies. Careful planning, fluid testing, and a fit-for-purpose completion design resulted in a successful hydraulic fracturing operation. The microseismic equipment was installed and monitored during the fracturing operation to provide actual fracturing propagation noise signals.
This paper presents the well fracturing technology, operational procedures, and microseismic technology used to better understand reservoir behavior and geomechanics characteristics. The geophone installation and surrounding control on location provided minimum noise interference for more accurate actual fracture propagation data. The computer program then forecasted fracture propagation. Comparisons between actual fracture propagation and the simulated fracture design allowed the operator to better understand subsurface parameters and characteristics for building the reservoir database. The operator was also able to forecast fracturing dimensions to help prevent water production zones. This significant reservoir information can be used for field development to maximize hydrocarbon production.
Fracturing technology and seismic technology were combined to improve the probability of successful hydrocarbon production. Microseismic results demonstrated the actual fracturing plane dimensions and dynamic fracture propagation, and the fracturing computer program provided fracture simulation dimensions and direction. Combining these technologies allowed the operator to obtain more reservoir data for future field development.
Yuan, Peng (Baker Hughes Incorporated) | Yu, Bo (Baker Hughes Incorporated) | Solomon, Herlene (Baker Hughes Incorporated) | Zhang, Hao (Baker Hughes Incorporated) | Stevens, John (Baker Hughes Incorporated) | Mezzatesta, Alberto (Baker Hughes Incorporated) | Gonuguntla, Praveen (Tridiagonal Solutions, Inc.)
The economic success of many drilling operations depends on the availability and reliability of real-time information about the drilling process. Mud pulse telemetry is currently the most common method of transmitting measurement-while-drilling (MWD) and logging-while-drilling (LWD) data. Advances in downhole sensing for drilling optimization and formation evaluation are placing heavy demands on telemetry systems to provide fast and reliable data rates from greater depths. However, solid particle erosion poses a significant problem for telemetry tools, where solid particle (such as sand) impingement could damage the tool string and shorten the service life of the tools. Therefore, a comprehensive investigation on erosion of mud pulse telemetry tools consisting of numerical simulation and field tests is often required to optimize the tool design.
In the field, many factors can influence telemetry tool erosion such as material properties, sand size, geometry, flow velocity, operating pressure, and turbulence. These factors interact with each other, making the experimental study of all influencing parameters very challenging and time-consuming. In this work, computational fluid dynamics (CFD) simulations were used to study the effect of several parameters on the erosion rate, even in complex geometries where setting up an experimental study is difficult. The erosion rate was determined using the widely used Oka erosion model. Parameter studies were then performed to find the influence of flow rate and sand concentration on the erosion rate. Simulation was also performed to support the deployment of new engineered materials. For model validation, simulation results were compared with erosion patterns from field tests, showing good agreement between field observations and simulation results.
Based on findings from the parameter studies, a formula of key performance indication (KPI) parameter was developed to evaluate the erosion performance of the mud pulse telemetry tools deployed in the field. After completing the field experiments, 3D laser scans of the deployed tools with different materials were performed. In addition, KPI values were calculated based on the scanning results to evaluate the actual erosion performance. Evaluation revealed that the new engineered alloy was eight times more erosion-resistant than stainless steel, which was consistent with the CFD simulation results.
The results of this study indicate that CFD simulation provided an alternate way to predict solid particle erosion on logging tools in downhole environments. By using the high-fidelity erosion model, the tool erosion rate could be accurately predicted. Based on this conclusion, the erosion risk can be mitigated by providing guidance on repair and maintenance intervals and planning the drilling process to avoid premature tool failures. This approach will eventually improve the reliability and safety of downhole tool and reduce non-productive time (NPT) and costs.
Malik, Ataur R. (Saudi Aramco) | Yaseen, Ali H. (Saudi Aramco) | Ogundare, Tolulope M (Saudi Aramco) | Asiri, Mohammed A. (Saudi Aramco) | Younis, Abdulmohsin A. (Saudi Aramco) | Driweesh, Saad M. (Saudi Aramco) | Shammari, Nayef S. (Saudi Aramco) | Ahmed, Danish (Schlumberger)
The objective of this paper is to highlight first worldwide implementation of coiled tubing (CT) compatible self-degradable fiber laden diverter for matrix stimulation treatment using enhanced high rate fiber optic real time telemetry system.
The self-degradable fiber laden diverter has been used in bullheading acid stimulation treatments aimed to maximize reservoir contact and enhance gas production. Recently, the physical properties of fiber has been re-engineered enabling them to be pumped down coiled tubing to enhance diversion and stimulation effectiveness. Coiled tubing with fiber optic real-time telemetry has been utilized for many years in Saudi Arabia for matrix stimulation treatments and well interventions as it provides real-time bottom-hole parameters such as pressure, temperature, casing collar locator, gamma ray, tension and compression as well as distributed temperature sensing (DTS) to optimize fluid placement. The successes achieved with previously used 2 1/8-in. bottom-hole assembly (BHA) for coiled tubing with real time telemetry system offered the maximum rate of 2.0 barrel per minute (bpm), whereas this rate became a limitation to achieve the desired fiber concentration for diversion when fiber laden fluids were used. The low rate provision by 2 1/8-in. BHA led to the need of a new generation high rate 3.25-in. BHA to be used for coiled tubing fiber optic real-time telemetry system that can enable higher pumping rates, help in achieving the desired fiber concentration.
For the first time in Saudi Arabian Carbonate reservoir, the novel fiber laden diverter was used during matrix stimulation treatment through 180 ft. perforated interval with new generation 3.25-in. bottom hole assembly (BHA) for coiled tubing fiber optic real-time telemetry system. The DTS used with the new generation coiled tubing high rate fiber optic real-time telemetry system helped in pre- and posttreatment evaluation. After successful high pressure coiled tubing stimulation using self-degradable fiber laden diverter with visco-elastic surfactant based acid system, the well performance exceeded expectation.
The encouraging result was achieved by uniform stimulation coverage throughout the long perforation interval. The operation also proved the feasibility of using the new generation of fiber optic real-time telemetry system in challenging environment.
The Static Mixer is a motionless mixer in which fluids are injected and rapidly mixed by combination of alternate vortex shedding and intense shear zone turbulence. It is a compact mixing plate with injection nozzles on two sides to ensure excellent distribution (
Huang, Xu (Baker Hughes Incorporated) | Yuan, Peng (Baker Hughes Incorporated) | Zhang, Hao (Baker Hughes Incorporated) | Han, Jiahang (Baker Hughes Incorporated) | Mezzatesta, Alberto (Baker Hughes Incorporated) | Bao, Jie (Pacific Northwest National Laboratory)
During the fracturing treatment, fracturing fluid is pumped to generate fractures and then followed with a large amount of proppant to provide enough conductivity for reservoir fluid to flow to the wellbore. The ultimate proppant distribution in the fracture system directly impacts well productivity and production decline rate. However, it is very challenging to predict how far proppants can go and where they will settle because of the complexity of the fracture system. Previous modeling and experimental studies were usually based on simple proppant settling velocity models and limited only to planar fracture cases. In a recent numerical study, proppant transport in different complex fracture geometries was modeled. However, the fracture walls in the model were considered to be perfectly smooth.
In this study, proppant transport in complex fracture geometries with different wall roughnesses was investigated using computational fluid dynamics (CFD) model, in which the interaction between proppant particles, the carrying fluid phase, and the rough fracture wall was fully coupled. A planar fracture case with smooth fracture wall was first investigated using a CFD model and benchmarked with results from commercial software. The CFD models were then used to simulate the proppant transport in T-junction and crossing-junction scenarios with different fracture wall roughnesses, which are often seen in unconventional reservoir fracture systems.
The results from the CFD models indicate that proppant transport within complex fracture geometries is significantly affected by fracture wall roughness. Rough fracture wall can exert resistant drag force to proppant particles and carrying fluids and hence influence the proppant transport behavior and particle distribution. It is found rough fracture wall decreases both proppant horizontal transport speed and vertical settling speed which can lead to a better vertical coverage of proppant particles in the fracture. However, more pumping energy and time are required to transport the proppant particles to the same fracture length with rough fracture surfaces compared to smooth fracture surfaces. Studies on proppant density show light weight proppant has a better vertical distribution in fractures with rough walls due to more pronounced drag force effect. With high viscous carrying fluids, proppant in both smooth and rough fractures can transport further at the same transport time.
Proppant transport models developed in this work fully incorporate the interaction between proppant particles, carrying fluid dynamics, and rough fracture surfaces. This study extends the current understanding of proppant distribution in complex fracture geometries and helps optimize hydraulic fracturing design to improve unconventional well production performance.