In planning for their first TLP deep water project in Malaysia, Shell faced the unique challenge of drilling ERD wells in soft unconsolidated sands with narrow ECD margins. Prior experience suggested the benefit of managed pressure drilling & an additional casing profile with hole enlargement to be implemented for these wells. The formation is also believed to be time sensitive, and reducing the wellbore exposure time between drilling and running liner was considered a priority.
A full suite of LWD services were also planned to be run on these sections, resulting in potentially a very long rat hole as the conventional reamer can only be placed above LWD tools. An additional hole opening trip to minimize rat hole length was not desirable, which in turn leads to concerns of well bore stability due to time exposure as highlighted earlier, as well as increasing potential risk of side tracking in the soft interbedded formations. Flow rate restrictions due to the pressure drop requirements from conventional reamers, was not desirable so as to maintain ECD stability.
In order to address the needs and challenges above, contractor proposed a dual digital reamer solution, in order to ream and drill the hole sections in a single run. The digital reamers, each being powered by the LWD suite, were activated via downlinks, eliminating the lengthy time required by drop ball reamers at high angles. The ability to downlink on demand and perform selective reaming without any pressure drop restriction, had provided added benefits while drilling in narrow ECD margin. As placement of the digital reamers are flexible within the LWD tools, dual reamers were deployed in the BHA. The top reamer located above the LWD tools was activated while drilling to ensure necessary LWD data quality was obtained. A near bit digital reamer was activated post-drilling to eliminate the long drilling rat hole, resulting in minimal rat hole achieved similar to the outcomes of a dedicated trip. Eliminating the dedicated trip also greatly minimized the risk of unintentional side track.
The use of dual digital reamers enabled safe and problem-free drilling, logging, casing and cementing; allowing all of Shell’s objectives to be met in a single run, as well as significant exposure time of the wellbore, up to 3.5 days over 3 hole sections and costs savings, up to 1.2mil USD.
Kuwait Oil Company (KOC) is developing its shallow heavy oil field using thermal method. Top risk of this project is the cap rock failure. If failure occur, it may lead to the steam leakage, overlying aquifer contamination, ground heave or subsidence and surface collapse. For the monitoring ground deformation caused by cyclic steam stimulation (CSS) and steam flooding (SF) thermal operation in Kuwait, InSAR technology is being considered. Interferometric Synthetic Aperture Radar (InSAR) is a remote sensing technique to measure surface heave and subsidence.
First stage of heavy oil thermal development in North Kuwait comprises production from shallow Miocene reservoirs covering an area of roughly 30 square kilometers, by two or three cyclic steam stimulation (CSS) process followed by steam flooding (SF) process. Main reservoirs are the shallow Tertiary un-consolidated sandstone within the measured depth of 650 to 750 feet, sealed off by Up Shale layer that is about 30 FT thick. High pressure and temperature steam will be injected to reservoirs zones, which could result in cap rock breach causing surface heave or subsidence. High-precision and frequent measurements of surface deformation is very important for the study of cap rock integrity.
With the advancement of InSAR technology, millimetric precision of ground deformation measurement is possible. The important factors affecting measurement accuracy of ground deformation is Radar microwave length. The most common of microwave is the L band with 24 cm wavelength, the C band with 4-8 cm wavelength and the X band with 2.5-4 cm wavelength. The choice of wavelength influences the precision. However, there are some other factors which have impact on measurement quality such as spatial density of the measurement points, climatic condition, distance between the measurement points and reference points, number and temporal distribution of acquisitions.
InSAR technology is expected to provide regular surface deformation maps during heavy oil production to monitor the cap rock integrity and to optimize wells and reservoir management. This technology has many benefits, such as reliability, simplicity, low cost, weather independent, minimal field intervention and ability to acquire at night. The absence of vegetation growth in our field area makes this technology very effective. To increase the frequency of data collection and to improve the accuracy of the deformation maps, satellite ascending and descending images are also used. Use of ascending and decending images helps in calculating the vertical and horizontal deformations from the Line of Sight (LOS) measurmemnts.
Production deferment due to wellbore sanding issues is a major risk for heavy oil field development. The heavy oil reservoir in Kuwait is a multi-stacked unconsolidated formation, which is prone to sanding. Currently there are two steam flood pilots in inverted 5-spot pattern configuration with pattern areas of 5 and 10 acres. The wells were operated for two cycles of Cyclic Steam Stimulation (CSS), before their conversion to steam flood.
Different Sand Control equipment is field tested in some pilot wells to optimize production in this viscous oil-saturated unconsolidated sandstone reservoir. This paper will discuss the operational challenges and the difference in the performance of cold production and after thermal CSS cycles of the installed Stand-Alone Sand Screens (SAS), which were retrofitted in the pilot wells. The mesh size of the SAS was designed based on the particle size distribution and well operating condition.
A comprehensive reservoir and well surveillance program was conducted to monitor and gather necessary data to characterize the reservoir and well performance in the pilot wells equipped with sand control equipment. The primary objective was to determine the optimal sand control strategy, moving forward in to the commercial phase of field development.
This paper will discuss the learnings from the pilot wells. The various SAS used were partially successful in mitigating sand production. More piloting with advanced sand controlling technologies at both laboratory and field levels may be required to reach to the optimum design for the field-specific cases.
The well trials using SAS was mainly to assess the screens regain permeability (skin) versus crude oil production while minimizing sand movement within the wellbore. This helped to improve the artificial lift pump run life and minimize sand debris from entering the pump.
A nationwide EOR screening was conducted on major oil fields in Kuwait with the aim to support KOC's long-term production strategy. Taking the many fields, and multitude of reservoirs into account, an efficient screening methodology was applied to high-grade potential EOR targets to focus on the most promising target formations.
This EOR screening methodology is an integrated approach of three steps. The first step applied parametric screening criteria of the various EOR technologies to the target formations of the study. The second step utilized analytical forecast models estimate tertiary recovery factors. The third and final step of this EOR screening methodology focused on generating a technical risk and opportunity profile for each filed, formation and applicable EOR technology.
This EOR screening methodology consisted of three steps. The first step applied parametric screening criteria of the various EOR technologies to the target formations of the study. The EOR processes in this parametric screening exercise included miscible gas EOR (such a CO2 and N2 as an example), chemical EOR technologies as well as thermal recovery technologies. During this first part of the EOR screening, the EOR technology yielding the highest incremental oil recovery in each formation was further studied while using analytical forecast models to link operational recovery drivers, such as throughput volumes and rates, to tertiary recovery factors. The third, and final step of this EOR screening methodology focused on generating a technical risk and opportunity profile for each field and formation under EOR screening while considering aspects such as EOR technology maturity, relative cost comparison and infrastructure constraints, to name a few. Integrating these three screening steps enabled to first, quickly focus on applicable EOR technologies for each target, second quantify a range of tertiary recovery factors and third estimate the risk profile. Combining these three outcomes enable to screen a portfolio of potential EOR opportunities quickly to find the most attractive target for further studies.
The novelty is the integrated EOR screening approach of combining parametric screening, analytical tertiary recovery forecasts and risk profiles to high-grade a portfolio of potential EOR targets for decision making.
Jain, Bipin (Schlumberger) | Mesa, Alvaro Martin (Schlumberger) | Kalbani, Sultan Al (Schlumberger) | Meyer, Arnoud Willem (Schlumberger) | Aghbari, Salim (Petroleum Development Oman) | Al-Salti, Anwar (Petroleum Development Oman) | Hennette, Benjamin (SHELL) | Khattak, Mohammad Arif (Schlumberger) | Khaldi, Mohammed (Petroleum Development Oman) | Al-Yaqoubi, Ali (Petroleum Development Oman) | Al-Sharji, Hamed Hamoud (Petroleum Development Oman)
Oman is a hotspot for drilling activity and wells are being drilled in different environments varying from Deep exploration and development for gas and oil and water injection/disposal. One challenge tops all other challenges: Lost Circulation. Due to the fractured/fissured nature of the formation and low existing reservoir pressures, all major operators are suffering from lost circulation challenges. Some of the challenges include: Mud losses while drilling leading to cost overruns and HSE concerns, primary cement job failure due to not getting the cement up to the desired height resulting in subsequent sustained casing pressure and corrosion, not able to perform work over activity on certain wells due to losses. Enormous quantities of water are required to maintain well control, and due to the limitation of water availability all over Oman, this becomes another critical issue. An Engineered fiber-based Loss Circulation pill has proved successful to address these challenges in multiple fields for Petroleum Development Oman.
Drilling shallow wells in Oman through the naturally fractured limestone formation of Natih, usually results in significant losses of up to 55 m3/h (346 bbl/h) even with a low density drilling fluid of 1,033 to 1,070kg/m3 (8.6 to 8.9lbm/gal). Packoffs are often observed due to the swelling shale section, which leads to several attempts with kick-off plugs and sidetracking. Engineered fibers pills enabled total returns to surface when no other loss circulation solution had worked before. This also enabled to bring cement all the way to surface using 1,410kg/m3 (11.8lbm/gal).
In another field, a work over rig was mobilized to perform a well kill operation and pullout. Due to total losses through perforations into the reservoir, the well kill could not be completed. In addition, every time the water level fell gas started to flow in the well. After 17 attempts and 8 loss circulation material pills, a total of 763m3 (4,800bbl) of well-supply water had been pumped. An engineered fiber pill at 1,474kg/m3 (12.3lbm/gal) was designed and bullheaded into the perforations. The pressures while pumping and squeezing rose to 11,031kPa (1,600psi). The well was shut and observed for 3 hours without any pressure increase indicating losses were cured and gas flow stopped.
Engineered fibers have proved their value in all sorts of lost circulation applications in North Oman. These pills have been successfully used to mitigate losses while drilling, while cementing, during mud circulation before cement job when the casing is on bottom and in work over jobs in depleted reservoirs. With the level of success achieved with such treatments, in some fields it has become a standard practice for curing losses.
Cramer, Ron (Shell Global Solutions) | Goh, Keat-choon (SHELL) | Iyer, Mahesh (Shell Global Solutions US Inc.) | Wali, Nwuche Nnamdi (Shell International Exploration & Production) | Spense, Bill (Shell International Exploration and Production) | Kessler, Guus (Norske Shell) | Kanten, Roy (Shell Canada)
The purpose of this paper is to document Shell's experiences and learnings inthe effort to better track and reduce Green House Gases (GHG) and improveEnergy Efficiency in our downstream manufacturing and upstream productionoperations. The paper is based on Case Studies from various Operating Units inShell upstream and downstream operations, as well as outlining furtherdevelopment plans.
In Shell operations we seek to minimize GHG emissions by continuouslymonitoring, displaying and reporting associated Key Performance Indicators(KPI's) and quickly alerting operators of changes to trigger remedialintervention. Reduction of GHG emission is also achieved by improving crossvalidated and mass balanced tracking of our process streams. This ensures thatmanufacturing and production processes are operated efficiently andtransparently.
Continuous GHG monitoring also allows automatic compilation of emissions bysource which can then be automatically reported as part of the normal dailyreporting cycle. The resulting emissions figures and associated KPI's are thenprominently displayed in the Daily Production Report. The daily emissionstotals are also stored and trended to flag more subtle and/or gradual changes.In this way GHG emissions data and performance information are made availableto operations staff and management to facilitate awareness and correctiveactions when appropriate.
By 2050 the world's energy demand is likely to double - yet more than halfthe energy we generate every day is wasted. At the same time the world isbecoming increasingly more carbon constrained and in order to counter thesechallenges, Shell has defined a number of strategic pathways as part of theiroverall GHG management strategy and policy. The first strategic pathwayfocusses on energy efficiency in our own operations, both for existing and newassets. Energy efficiency is regarded within Shell as good business, yieldingoften attractive and immediate business value, while also providing improvedrobustness in the sustainability and profitability of our operations,especially in a carbon constrained world.
The management process starts with understanding and measuring energyconsumption and GHG emissions and embedding this in our daily decision makingprocess while also using the "CO2 lens" for driving and validating the designchoices in our new assets. In order to do this successfully, real-timemeasurement of the key process parameters is required. This will provide theoperator with instant feedback of his process / operational choices re theimpact on energy intensity and GHG emissions. It can be compared with the fuelefficiency indicator in modern cars. By providing this feedback, it stimulatesbehavioural change and positions energy efficiency as a core value to beoptimised using daily operations.
The pupose of this paper is to describe a number of case studies as arepresentative subset of our activities, and describe how real-time datameasurement and surveillance can be used to support our drive for operationalexcellence in energy efficiency, thereby focussing on the following of ourglobal businesses:
• Upstream E&P European operations - derived from real time processmeasurements;
• Downstream assets - derived from real time process measurements;
• North American mid-stream operations - derived from a combination ofreal time process measurements and valve flow estimates
• International upstream E&P assets - derived from a combination ofwell gas flow estimates and real time process measurements
Note, Shell is also very active in the area of CO2 sequestration - this outwiththe scope of this paper and is described elsewhere (Ref. 1)