Du, Xuan (Research Institute of Petroleum Exploration & Development, PetroChina Co. Ltd.) | Zheng, Haora (Research Institute of Petroleum Exploration & Development, PetroChina Co. Ltd.) | Wang, Xiaochun (Research Institute of Petroleum Exploration & Development, PetroChina Co. Ltd.) | Hua, Xin (China Petroleum Technology Development Corporation, PetroChina Co. Ltd.) | Guan, Wenlong (Research Institute of Petroleum Exploration & Development, PetroChina Co. Ltd.) | Zhao, Fang (Research Institute of Petroleum Exploration & Development, PetroChina Co. Ltd.) | Xu, Jiacheng (Research Institute of Petroleum Exploration & Development, PetroChina Co. Ltd.)
Heavy oil reservoirs are generally unconsolidated and easy to produce sand during production
Eldabbour, Mohamed (Abu Qir Petroleum) | Fadel, Ayman (Abu Qir Petroleum) | Soliman, Ali (Abu Qir Petroleum) | Safwat, Hatem (Abu Qir Petroleum) | Labib, Amr (Abu Qir Petroleum) | Belli, Andrea (Abu Qir Petroleum) | McLaughlin, Ryan (Corex U.K. Ltd) | Patey, Ian T.M. (Corex U.K. Ltd) | Munro, Murdo S. (Corex U.K. Ltd) | Jones, David (Corex U.K. Ltd)
Gravel pack completion operations are a sand production management technique that is considered successful if the well produces no sand and has minimal impact upon the potential productivity and hydrocarbon recovery. However, statistics show that many gravel packed wells suffer reduced productivity as a result of damaging mechanisms induced by gravel pack operations and completion fluids. This provides an opportunity for improved hydrocarbon recovery if the mechanisms are understood.
A study was conducted to simulate the alterations caused by the gravel pack operations including gravel carrier fluid, completion fluid and lost circulation material. Simulations using reservoir core samples were carried out at near-wellbore conditions, in order to examine operational fluid interactions with the reservoir and assess the impact of a stimulation fluid. Cores from a range of rock types were selected, and prepared to initial gas-leg saturation. An operational sequence consisting of completion fluid, gas production, stimulation fluid, completion fluid, and production of gas was carried out, with permeability measurements before and after the sequence.
In all core samples, the introduction of the completion fluid during gravel pack installation resulted in alterations of 30-60% reduction in core permeability. Geological interpretative analysis showed damage mechanisms including clay fines movement and pore blockage, dissolution of native cement, and retention of operational fluid in the pores. It was believed that retention of fluids was having the most significant impact upon permeability. Stimulations were carried out for all samples to quantify the effect of acid on removing the formation damage resulting from the gravel pack operations. The experiments showed 5-10% improvement on average except for one core sample, which showed 40% improvement.
Based upon the previous results, a modified sequence was examined, utilizing an alternative stimulation fluid/acid sequence and adding an extra operational stage. The experiments showed that after treatment an improvement of around 10% was noted, and after an additional stage, a further 8% improvement was seen. The final permeability was over 80-90% of the initial permeability, indicating that there was the potential for good productivity and recovery of hydrocarbons.
The results of the study were applied to seven gravel pack jobs in three wells and the field results showed the reduction in productivity after gravel pack installation was around only 10%, compared to previous wells which showed more than 50% reduction in productivity.
Faster production declines than initially forecast were observed in numerous deep-water assets. These wells were completed as Cased Hole Frac-Pack (CHFP) completions (
Seven key damage mechanisms were identified as forming the basis for PI degradation: 1) off-plane perforation stability, 2) fines migration, 3) fracture conductivity, 4) fracture connectivity, 5) fluid invasion, 6) non-Darcy flow and 7) creep effects. A near wellbore production model incorporating the completion, fracture geometry and reservoir is coupled with a geomechanics model to assess each mechanism. A Design of Experiment setup varies the input ranges associated with each of the seven damage mechanisms. Input parameters for the model are risked and rely on ranges from standard and newly developed well and lab tests. The model assesses well performance and driving mechanisms at different points in time within the production life.
Primarily the study focused on high permeability and highly over pressured reservoirs. For the types of wells/fields assessed in the study, the results indicated three phases of decline based on the interaction between the formation properties, the completion components and the operating parameters. The three phases breakdown into: (1) a pre-rock failure stage where declines are relatively small, (2) an ongoing rock failure stage where declines are rapid and (3) a post failure stage where declines are again moderate. In each of these stages different parameters and damage mechanisms were assessed to be impactful. The workflow was also utilized to match pre and post acidizing treatments. A comparison for varying rock types was included looking at the impact of rock strength and formation permeability on the ranking of the damage mechanisms. The impact of operating parameters such as drawdown can also be assessed with the tool showing that increased drawdowns may not always be beneficial to the long-term production of the well.
The paper presents the underlying drivers for PI Decline for deep-water assets of a specific attribute set. Through accurate representation of reservoir and completion, the workflow highlights the impact and combined impact of different damage mechanisms. The paper also shows a direct link between the mechanical properties (moduli and strength) and boundary conditions (pore pressure and stress) and the well performance and productivity. The workflow provides a methodology by which lab and field tests can be transformed into assessments of future well performance without strictly relying on analogs that may or may not be appropriate.
Murdoch, Euan (Weatherford Completion Systems) | Walduck, Steve (Weatherford UK Ltd) | Munro, Chris (Weatherford UK Ltd) | Edwards, Andrew (Weatherford) | Choquet, Caroline (Weatherford Energy Services)
Successfully deploying a single trip completion system in a deep-water environment requires an innovative technical solution to address the risks that come with this environment. Following a request from the operator for a deep-water single trip solution, a number of different system options were proposed. Each system was evaluated against the operator’s requirements, and a Radio Frequency Identification (RFID) technology-based system was selected as it offered the greatest flexibility in both activation and contingency methods to meet the demands of the project.
It was proposed to hold a 2 stage System Integration Test (SIT) at a test rig in Aberdeen. The first SIT was performed with a small number of tools that could be setup in different modes to prove the system’s logic against the operator’s expectations. Whilst this was conducted successfully a number of learnings and operational optimisations were captured. These were fed into a full-scale SIT which was deployed at the same test rig. This second SIT involved a complete representation of the single trip system and was designed to test the final system logic prior to deployment into an offshore environment.
The system was then installed successfully in November 2018, on a subsea well, offshore Nigeria with no intervention. It resulted in an operational time saving of at least 60% over the previous best recorded time for a conventional two-trip completion from the same rig. This represented a step change in operational efficiency and will now be the operator’s base case completion methodology as they develop the field further.
This is the first time a single trip completion has been deployed in this fashion in a deep-water, offshore environment. The demonstrable step change in operational time and resultant project OPEX savings, proves that the use of RFID and remote actuated tools within completions offer excellent alternatives to traditional methods.
Sand management has become in one of the most vital factors in today's upstream oil and gas industry, more and more are the cases where the sand control systems play an important factor to determine the economic viability of each project. This paper will focus in a solution for sand problems in ESP systems applying to sand slug breakdown using a 10 V-Mesh Sand Screen to homogenize the solid inflow in the system so it would be easier to handle the solids through the ESP's stages. The implementation of the screen intake for the homogenization of solids in an ESP well allowed to efficiently manage sand slugs, improving the pump efficiency and avoiding blocking problems in the pump caused by sand. Furthermore, the system allows increasing the frequency of operation of the ESP motor to have a greater drawdown, increasing the production of the fluid from 1600 BFPD to 1800 BFPD. The behavior of the sensor data such as vibration, current, and voltage remained stable throughout the period evaluated, extending the run life of the system.
Traditional sand control sizing has typically been based on "standard", wide-sieve gravel distributions (i.e. 20/40, 16/30, etc). Historic sand retention testing has therefore been limited to these standard gravel (i.e. proppant) sizes. With the emergence of new proppant technologies, extensive testing has recently been performed to evaluate the impact of mono-sieved gravel on sand retention performance.
Sand retention testing was performed using a number of industry test protocols [
Comparison of the mass of produced sand through various combinations of formation/gravel are useful in identifying the preferred gravel to manage solids production. This study will show that sand control performance of mono-sieved gravel is comparable to that of standard-sieve distribution gravel. This is illustrated by comparing the mass of produced sand and measurement of permeability in the various formation/gravel combinations. The paper will demonstrate that numerous "rules of thumb" employed for gravel sizing (including use of "Saucier's ratio") during the gravel- and frac-pack design process can be applied to any sieve distribution gravel, whether standard- or mono-sieved. In addition to the test results, this paper will reference multiple GOM applications with frac-pack completions in which sand control is performing as designed using mono-sieved gravel.
This paper is critical for all completions engineers who are designing gravel or frac-pack completions. Sand retention testing on mono-sieved gravel is novel, and these results complement existing testing. The results of this testing have already been applied by several exploration and production companies, and this paper will allow others to benefit from the work.
SPE President Giovanni Paccaloni's column in the February 2005 Journal of Petroleum Technology described the central role of young professionals in the future development of the oil and gas industry. In his March column, he stressed the "urgent priority for public energy education." To bridge the wide gap between the students and the industry, two members of the Aberdeen ELP voluntarily agreed to provide in-house seminars on April 28 and 29 at the university. The seminars featured Gillian King of Weatherford speaking on "Expandable Sand Screens" and Imona Adebo of Chevron Corp. speaking on "Production Management." An industrial visit was also organized to Shell's Goldeneye gas terminal at St. Fergus on May 3. The Student President of the Robert Gordon U. SPE Chapter, Olumakinde Ilesanmi, said the goal of the chapter had always been to foster relationships between its members and the industry.
Several SPE students from Robert Gordon U. recently took part in a tour of the Weatherford Completions and Production Facility in Dyce, Aberdeen. Those who attended are all studying various oil and gas engineering disciplines. To show students some of the practical aspects of theoretical teachings, Weatherford offered insight into completion practices, especially in sand control. Students spent most of the day at the facility with Gillian King, Product Line Champion in Sand Control Systems, who gave an introduction to the company, its various divisions, and its global operations. The tour focused on Weatherford's contribution to the industry in sand control, primarily its expandable sand screen and the technology behind it.
Three young professionals shared advice for career and personal advancement as well as information about their involvement in and growth through SPE and other activities in a special panel session at the 2006 SPE Annual Technical Conference and Exhibition. Attendees at the "Young Professionals: Tips, Advice, and Networking" event also learned about the importance of mentoring and were given the opportunity to meet with other professionals and company management. Moderated by Josh Etkind, Reservoir Engineer–Surveillance for Shell E&P, the panel also included Gillian King, Product Line Champion, Sand Control Systems for Weatherford Intl. Discussing the help of mentors in his career, Daniels said he "jumped into the deep end" early in his career and he was glad there was a lifeguard on duty. "Young professionals have a responsibility to seek out people to learn as much as they can," he said.
This course discusses the fundamental sand control considerations involved in completing a well and introduces the various sand control techniques commonly used across the industry, including standalone screens, gravel packs, high rate water packs and frac-packs. It requires only a basic understanding of oilfield operations and is intended for drilling, completion and production personnel with some sand control experience who are looking to gain a better understanding of each technique’s advantages, limitations and application window for use in their upcoming completions.