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Geostatistical reservoir-modeling technologies depart from traditional deterministic modeling methods through consideration of spatial statistics and uncertainties. Geostatistical models typically examine closely the numerous solutions that satisfy the constraints imposed by the data. Using these tools, we can assess the uncertainty in the models, the unknown that inevitably results from never having enough data. Reservoir characterization encompasses all techniques and methods that improve our understanding of the geologic, geochemical, and petrophysical controls of fluid flow. It is a continuous process that begins with the field discovery and all the way through to the last phases of production and abandonment.
Total recoverable oil resources around the globe fell to 1,725 billion bbl, according to a newly published estimate from Rystad Energy on Tuesday. The figure represents a drop of 9% on a year-over-year basis from 2020's estimate of 1,903 billion recoverable bbl. The trendlines Rystad has drawn point toward oil and natural gas liquids production falling below 50 million B/D by 2050--or about 50% off the peak seen prior to the COVID-19 pandemic. This spells bad news for the outlook of many oil companies, but for those still pumping in 2050 it may signal that the industry has succeeded in striking a balance between meeting the world's energy needs and its climate concerns. Per Magnus Nysveen, Rystad's head of analysis: "Exploring, developing, processing, and consuming this amount of commercially extractable oil will lead to gross greenhouse-gas emissions of less than 450 gigatons of CO2 from now until 2100. This is compliant with [the Intergovernmental Panel on Climate Change's] carbon budget for global warming limited to 1.8 C by 2100."
Developing a corporate safety attitude to reduce and hopefully eliminate injuries, accidents and releases of toxic chemicals has been practiced for many years. The activities and technologies described below are interconnected with other safety approaches; however it is useful to consider them separately since they are primarily associated with different parts of most jobs. The hurt based approach to safety is a methodology for assessing safety incidents with high consequence potential. This approach helps to determine the depth of investigation requirements (in addition to actual severity). The hurt based approach is used to identify the integral potential and consistent actual severity of an incident and also used as a safety culture enabler.
Although reserves estimates for known accumulations historically have used deterministic calculation procedures, the 1997 SPE/WPC definitions allow either deterministic or probabilistic procedures. Each of these is discussed briefly in the next two sections. Thereafter--except for another section on probabilistic procedures near the end--the chapter will focus on deterministic procedures because they still are more widely used. Both procedures need the same basic data and equations. Deterministic calculations of oil and/or gas initially in place (O/GIP) and reserves are based on best estimates of the true values of pertinent parameters, although it is recognized that there may be considerable uncertainty in such values.
Schlumberger and Panasonic have announced that they will collaborate on a new battery-grade-lithium production process that they say will pave the way for improved lithium production to help meet the expected surge in demand from the fast-growing global electric vehicle (EV) market. The announcement came from the Schlumberger New Energy arm of Schlumberger and from Panasonic Energy of North America, a division of Panasonic Corporation of North America. The lithium-extraction and -production process will be used by Schlumberger at the Nevada pilot plant of its Neolith Energy venture. According to Schlumberger, Neolith Energy's approach uses a differentiated direct-lithium-extraction process to produce high-purity, battery-grade lithium material while reducing production time from more than a year to weeks. The company also said the process significantly reduces groundwater use and physical footprint vs. conventional evaporative methods of extracting lithium.
Some Texas leaders and oil and gas industry advocates have for years promoted the idea that produced water--the waste water generated through oil and gas development--has a role to play in meeting broad water needs in the state. However, the state has a limited understanding of the chemicals in this waste water and how programs to reuse it outside the oil field could be practiced safely, if at all. Acknowledging the necessity to better understand treatment needs, economic challenges, and public health and environmental risks of industry's waste water, the Texas Legislature recently passed Senate Bill 601, establishing a Texas Produced Water Consortium. The consortium will be housed at Texas Tech University and will bring together a wide swath of agency advisors, technical experts, and key stakeholders to consider these issues and produce a report with recommendations over the next year. The group is charged with suggesting legal and regulatory changes to better enable beneficial uses, identifying pilot projects and assessing the economics of using produced water both efficiently but also in a way that protects public health and the environment.
Mendez Gutierrez, Freddy Alfonso (ADNOC Offshore) | Abdel Karim, Islam Khaled (ADNOC Offshore) | Oviedo Vargas, Mario Ramon (ADNOC Offshore) | Alzaabi, Mohamed Abdulrahman (ADNOC Offshore) | Al Ali, Salim Abdalla (ADNOC Offshore) | Toki, Takahiro (ADNOC Offshore) | Ramanujan, Jeughale (ADNOC Offshore) | Wagstaff, Scott (ADNOC Offshore) | Tanaka, Hisaya (ADNOC Offshore) | Iftikhar, Bilal (ADNOC Offshore) | Torres Premoli, Javier Ernesto (ADNOC Offshore) | Abdelhalim, Khaled (Coretrax, Churchill Drillling tools) | Juarez Moreno, Daniel (Weatherford) | Yadav, Anurag (Weatherford) | Chohan, Imran Muhammad (Weatherford)
Abstract A Major Operating Company in UAE planned and drilled a challenging 6 inch horizontal drain after crossing twenty-seven formation sub-layers. The heterogeneity of pore pressure varied from equivalent mud weights as high as 10.6 ppg to as low as 7.1 ppg across the exposed reservoirs. Control of the equivalent circulating density (ECD) values to safely drill across these multi-reservoir sections and diverse reservoir pressures was one of the top challenges on this well, as the fracture gradients (FG) ranged from 13.5 ppg across the competent reservoirs to as low as 11ppg across the fractured reservoir section. The offset well data review show that 4 out of 6 wells encountered moderate, severe and total losses with mud weight (MW) ranging from 11 ppg to 11.3 ppg, which were cured by using heavy LCM treatments and in some cases, after several failed attempts to cure losses, cement plugs were used. Historically, the average time spent curing total losses in these wells varied from 2-3.5 weeks causing well cost increments as consequence of this non-productive time. All of the above, without mentioning the extra efforts, resources and risks were faced due to well control and stuck pipe events which occurred on those wells. Engineering and Operation teams worked together to engineer a solution to drill this well in one run while safely maintaining the well under control and managing the losses. The Bottom Hole Assembly (BHA) was designed to withstand the well challenges including multiple contingency options. These options allowed:Improving hole quality while tripping using a special type of eccentric reamer stabilizer. Pumping various LCM concentration scenarios through a multi-cycle circulation valve. In addition, a special type of float valve was placed on the top of the BHA as barrier, stopping back flow under surface backpressure or kick scenarios. Optimizing mud weight by using formation pressure while drilling (FPWD) and monitoring both equivalent circulating density ECD and equivalent static density (ESD) by pressure while drilling tools. The drilling fluid was loaded with non-damaging loss circulation material without compromising the MWD/LWD limits. Additionally, the mud rheology was carefully selected and monitored to achieve the desired ECD. On surface, a managed pressure while drilling system was deployed to give control on reservoir pressures. In instances of influx, MPD allows to early detect any kick and controlled by surface back pressure without requiring shut in for applying standard well control techniques. Keeping the well under control by surface back pressure (SBP) during connections time (flow–off). Additionally, MPD also enables the contingency of applying pressurized mud capping in case of unable to control the losses. As decision point, a loss management plan was prepared and implemented. Also, a dynamic formation integrity test was planned and performed to calibrate the fracture gradient across the loss zones. The problematic zone was successfully drilled with one BHA in under six days (5.73 days). The estimated savings for the company were 8 days, which equates to ±1MMUS$ after including the MPD cost which increased the well cost by 200MUS$. To further complement the outright savings, the engineered solution managed to safely stave off operational complications as well as incurring the related complexities and non-productive time (NPT) as recorded on the offset wells. Additionally, well was successfully landed and geo-steered across the target formation and 4½ in liner was run and cemented off-bottom avoiding the need to develop a slot recovery scope on this well with an extra duration of +/-35 days. The engineered solution provided a high level of preparation and contingencies within the BHA, Managed Pressure Drilling Equipment, real time monitoring, mud and cement formulation. The applied techniques allowed the operating company to successfully execute this challenge well within the proposed time and budget.
Abstract This paper reviews the recently concluded successful application of a Managed Pressure Drilling (MPD) system on a High-Pressure High-Temperature (HPHT) well with Narrow Mud Weight Window (NMWW) in the UK sector in the Central North Sea. Well-A was drilled with the Constant Bottom Hole Pressure (CBHP) version of MPD with a mud weight statically underbalanced and dynamically close to formation pore pressure. Whilst drilling the 12-1/2" section of the well with statically under-balanced mud weight, to minimize the overbalance across the open hole, an influx was detected by the MPD system as a result of drilling into a pressure ramp. The MPD system allowed surface back pressure to be applied and the primary barrier of the well re-established, resulting in a minimal influx volume of 0.06 m and the ability to circulate the influx out by keeping the Stand Pipe Pressure (SPP) constant while adjusting Surface Back Pressure (SBP) through the MPD chokes in less than 4 hours with a single circulation. After reaching the 12-1/2" section TD, only ~0.025sg (175 psi) Equivalent Mud Weight (EMW) window was available to displace the well and pull out of hole (POOH) the bottom hole assembly (BHA) therefore, 3 × LCM pills of different concentrations were pumped and squeezed into the formation with SBP to enhance the NMWW to 0.035sg EMW (245 psi) deemed necessary to kill the well and retrieve BHA. MPD allowed efficient cement squeeze operations to be performed in order to cement the fractured/weak zones which sufficiently strengthened the well bore to continue drilling. A series of Dynamic Pore Pressure and Formation Integrity Tests (DPPT and DFIT) were performed to evaluate the formation strength post remedial work and to define the updated MMW. Despite the challenges, the MPD system enabled the delivery of a conventionally un-drillable well to target depth (TD) without any unplanned increase/decrease in mud weight or any costly contingency architecture operations, whilst decreasing the amount of NPT (Non Productive Time) and ILT (Invisible Lost Time) incurred. This paper discusses the planning, design, and execution of MPD operations on the Infill Well-A, the results achieved, and lessons learned that recommend using the technology both as an enabler and performance enhancer.
Abstract Accurate pore pressure prediction is required to determine reliable static mud weights and circulating pressures, necessary to mitigate the risk of influx, blowouts and borehole instability. To accurately estimate the pore pressure, the over-pressure mechanism has to be identified with respect to the geological environment. One of the most widely used methods for pore pressure prediction is based on Normal Compaction Trend Analysis, where the difference between a ‘normal trend' and log value of a porosity indicator log such as sonic or resistivity is used to estimate the pore pressure. This method is biased towards shales, which typically exhibit a strong relationship between porosity and depth. Overpressure in non-shale formations has to be estimated using a different method to avoid errors while predicting the pore pressure. In this study, a different method for pore pressure prediction has been performed by using the lateral transfer approach. Many offset wells were used to predict the pore pressure. Lateral transfer in the sand body was identified as the mechanism for overpressure. This form of overpressure cannot be identified by well logs, which makes the pore pressure prediction more complex. Building a 2D geomechanical model, using seismic data as an input and following an analysis methodology that considered three type of formation fluids - gas, oil and water in the sand body, all pore pressure gradients related to lateral transfer for the respective fluids were evaluated. This methodology was applied to a conventional reservoir in a field in Colombia and was helpful to select the appropriate mud weight and circulating pressure to mitigate drilling risks associated to this mechanism of overpressure. Seismic data was critical to identifying this type of overpressure mechanism and was one of the main inputs for building the geomechanical earth model. This methodology enables drilling engineers and geoscientists to confidently predict, assess and mitigate the risks posed by overpressure in non-shale formations where lateral transfer is the driving mechanism of overpressure. This will ensure a robust well plan and minimize drilling/well control hazards associated with this mode of overpressure.
Krikor, Ara (Schlumberger) | Sanderson, Martin (Schlumberger) | Merino, Lizeth (Schlumberger) | Benny, Praveen (Schlumberger) | Ibrahim, Sameh (Schlumberger) | Al-Khayat, Khaled (Schlumberger) | AlYasiri, Siffien (Schlumberger)
Abstract Drilling highly intercalated formations with Polycrystalline Diamond Compact (PDC) bits has been a challenge in few Southern Iraqi Fields. The established drilling practice for the 17.5-in section has been a two-run strategy - Top section formation is mostly dolomite intercalated with anhydrite drilled with a Tungsten Carbide Insert (TCI) bit, then trip out of hole to change to a PDC bit and drill to section TD. The upper section comprises highly intercalated formations known to induce severe bit and BHA damage. The application of new Conical Diamond Elements (CDEs) backing up traditional PDC cutters on the bit blades had significantly improved bit durability in the bottom half of the section. The subsequent challenge was to apply this CDE technology onto an optimized PDC chassis and achieve a single run section thus eliminating a trip for bit change as well as improving overall Rate of Penetration (ROP) of the section. A Bit and drill string optimization exercise was initiated by the Technology Integration Center to develop a new PDC bit design that could deliver a shoe-to-shoe section. Analysis of offset well data highlighted the need for greater cutter redundancy on the bit to survive high impact loading and optimized cutter arrangement to minimize bit induced instability while drilling through intercalations with highly fluctuating rock strengths. A finite element analysis (FEA)-based modelling system was used to evaluate the dynamic behavior of multiple bit design configurations in various rock scenarios and narrow down to the optimum design for the challenge. The optimization exercise shortlisted a PDC bit design characterized by 8 Blades, 16-mm PDC cutters and CDEs backing-up the nose and shoulder PDC cutting structure. A detailed drilling parameter road map was also generated to ensure optimum drilling parameter application for shoe-to-shoe assurance. The new bit drilled the entire section in single run with a field record average on-bottom ROP of 20 m/hr which was a 11% improvement over the best offset performance with a two-bit strategy. In addition, a trip for bit change was eliminated. A minimum saving of 20 rig hours was realized thus reducing section time by almost one day compared to the offset wells. The bit was pulled out of hole with minor cutter damage indicative of efficient drilling dynamics and opportunities for further performance enhancement through improved parameter management, alternate drive systems and high torque drill pipes. This paper further will discuss how the technology integration and precise engineering design can solve complicated on bottom drilling problems and address the problematic challenges of drilling highly intercalated formations. This strategy enabled a significant time and cost saving compared to drilling the section conventionally.