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Godfrey Edezu was born in the rural village of Ayivu, Maracha district, Uganda. His decision to study Geosciences was deeply rooted in earlier inspirations by the science teachers and fascinations to understand the extraction of natural resources from the earth. This career journey was well supported and perfected by his active involvement in SPE activities and leadership from the year 2012. Special thanks to the founders of SPE International whose benefits to world population speaks for itself. In 2013, Godfrey participated in SPE Africa region's Student Paper Contest and in 2014, he was also selected to participate in a group project during IPTC education week.
SPE, through its Energy4me programme, will present a free one-day energy education workshop for science teachers (grades 8–12). A variety of free instructional materials will be available to take back to the classroom. Educators will receive comprehensive, objective information about the scientific concepts of energy and its importance while discovering the world of oil and natural gas exploration and production. Energy4me is an energy educational public outreach programme that highlights how energy works in our everyday lives and promote information about career opportunities in petroleum engineering and the upstream professions. SPE’s Energy4me programme values the role teachers and energy professionals play in educating young people about the importance of energy.
A West Texas operator historically used four to seven PDC bits to TD their Ward County, Wolfcamp B laterals. Formations there are lithologically more challenging when compared to the same interval in adjacent Reeves County. Drilling performance in Reeves County Wolfcamp A laterals averages approximately 1,091 Feet/Day while those in Ward County seldom make 600 Feet/Day. Often daily progress is less than that. The objective was to improve Ward County lateral drilling performance.
In the study presented here, we examined the BHAs, bits and motors in consecutive Wolfcamp B laterals on the same pad which used 7 and 5 bits to reach TD respectively. Several of these PDC bits were Damaged Beyond Repair (DBR) as illustrated later. We demonstrate the process of utilizing Time Domain Analyses (TDA) as an accurate method to identify and analyze the nonlinear, dynamic behavior of drilling systems. These enhanced models allow the engineer to explore a full range of alternative BHA responses based upon current drilling conditions. They account for most of the specific details of downhole equipment such as the bit, the rotary steerable systems (RSS) or steerable mud motor, the MWD and their interaction with the hole. The software used allows virtual sensors to be placed anywhere along the drill string to evaluate the dynamics for additional insights.
Inflow Control Device(ICD) is considered to be an effective water control technology, especially in offshore reservoirs with strong bottom water, which is more conducive to slowing water breakthrough, increasing recovery factor during low water cut period, reducing produced water treatment costs and improving development effect.
The H oil field in Bohai Bay, China is a target oil field where horizontal wells are widely used by traditional ICDs. The characteristics of the H field are heavy oil (average viscosity of 260 mPa·s under reservoir conditions), excellent reservoir quality (up to 30% porosity and 3D permeability), loose sand, heterogeneity and strong aquifer.
In the process of water control in horizontal wells, the sand channeling and annulus channeling outside the sand control screen were the main factors that caused the water control failure by early ICDs. In the later design and application, the ideas and methods were improved. Based on the review of the conventional ICD application, a new work-flow was proposed to design and to optimize the ICD to improve the opportunities for success and to prolong the effective water control period.
Compared with the previous design ideas, more attention was paid to the segmentation and environmental control isolation methods:
In the case of reservoir heterogeneity uncertainty, increasing the number of segments and uniform segmentation is more conducive to accurate plugging and release potential. The most ideal condition is continuous step-less isolation. A new type of lightweight, high-strength, and easy-to-carry particles were used to fill the environmental control with high strength, which results in a step-less continuous horizontal sealing effect while preventing sand production. The particle filling volume and particle radius can be adjusted. The size of the particle radius determines the additional pressure drop of the loop control zone, and the filling volume determines whether the loop control channeling is completely avoided.
In the case of reservoir heterogeneity uncertainty, increasing the number of segments and uniform segmentation is more conducive to accurate plugging and release potential. The most ideal condition is continuous step-less isolation.
A new type of lightweight, high-strength, and easy-to-carry particles were used to fill the environmental control with high strength, which results in a step-less continuous horizontal sealing effect while preventing sand production. The particle filling volume and particle radius can be adjusted. The size of the particle radius determines the additional pressure drop of the loop control zone, and the filling volume determines whether the loop control channeling is completely avoided.
The improved ICD completion device had been successfully applied in 4 production wells in the oil field. The water cut of the well dropped by 10%, and the initial daily oil production increased by 145 barrels. This result greatly inspired our confidence. In the future plan, we are willing to adopt the plan to control water in 12 wells in two batches. And due to the improvement and quality control of key links in the design and process, implementation time have been significantly saved which is extremely important for offshore platforms to obtained good economy returns.
This article proposes a detailed, complete, and smooth work-flow, including actual oil field information, target well selection, segmentation method, fill volume estimation and implementation effect evaluation. This work-flow has great reference value for industry peers to improve the efficiency and quality control of hybrid ICD projects.
Pore-scale images and core-scale imbibition experiments suggest that hydrocarbon and water tend to flow through their own pore network, referred to as "stratified flow". The objective of this paper is to investigate the occurrence of these phenomena at reservoir scale by analyzing flowback and post-flowback production data. Understanding multiphase flow regimes is the first step for selecting proper relative permeability curves and developing representative multiphase rate-transient models. Another objective of this paper is to investigate the harmonic decline (HD) behavior of water-oil ratio (WOR) versus cumulative water production volume and how it could be employed to compare load recovery performance of different wells. We analyzed flowback and post-flowback production data of six multi-fractured horizontal oil wells completed in Eagleford Formation. The proposed data-driven methodology involves using multiphase diagnostic plots of rate-normalized pressure, rate decline, and WOR. We applied this methodology to i) investigate the relationship between water and hydrocarbon at early production time; ii) model WOR with respect to cumulative water production; and iii) evaluate how fracturing/completion design parameters affect well performance.
The results show three key findings: i) During early production time, we observe independent flow regimes (stratified flow) of water and oil indicating their production under different drive mechanisms. Water is produced from an apparently closed tank comprising induced fractures and the surrounding stimulated matrix, and oil is produced independently at a significantly lower rate due to oil influx from matrix into fractures. ii) After jet-pump installation, we observe coupled flow of water and oil indicating their production under similar drive mechanisms provided by the pump. iii) Semi-log plot of WOR versus cumulative water production shows HD trend that is relatively less sensitive to operational changes compared to water rate-decline plots.
The depletion of producing layers leads to significant stress changes in adjacent targets, especially when complex natural fractures are present. Due to weak bedding interfaces or small stress barriers, hydraulic fractures can easily penetrate neighboring layers, and this further increases the chance of multilayer stress disturbance. In this work, we investigate the effects of vertical fracture complexity, i.e., hydraulic fracture penetration and interlayer natural fracture existence, on stress interference between different layers using a data set from a typical shale gas well in the Sichuan Basin. Two geological contexts, i.e., without interlayer natural fractures (w/o INF) and with interlayer natural fractures (w/ INF), are considered under different degrees of fracture penetration and interlayer connectivity. An in-house iteratively coupled geomechanics and compositional reservoir simulator is used to model the three-dimensional pressure and stress changes. The non-uniform hydraulic fractures and stochastic natural fractures are incorporated in our coupled simulation with an embedded discrete fracture model (EDFM). Comprehensive spatial-temporal stress analysis quantifies the approximate range of orientation change of
Two earthquakes with moment magnitude (Mw) 3.9 and 4.1 occurred in January 2015 and January 2016 near the Crooked Lake, 16 km west of Fox Creek region, Alberta. These two earthquakes were attributed to the hydraulic fracturing operations of three horizontal wells on a nearby well-pad, which were stimulated 40 and 8 days before the seismic events. The underlying mechanism of the induced seismicity is still unclear and needs to be investigated to mitigate the risk of future events in this area. In this study, the coupled simulations of the fluid flow and geomechanics were conducted to characterize the temporal and spatial evolution of pore pressure diffusion and stress perturbation during and after hydraulic fracturing operations. The Coulomb Failure Stress on the pre-existing faults near the horizontal wells were then calculated to study the reactivation of the fault. Sensitivity analysis was finally conducted to understand the effects of the fault's orientation, the injection layer permeability and distance between the fault and hydraulic fractures on the induced seismicity.
It is found that one single fault oriented North-South was reactivated twice after the sequential fracturing operations of three horizontal wells and two earthquakes were triggered in 2015 and 2016. The earthquake of Mw 3.9 was triggered by the stress and pore pressure changes in the Basement part of the fault. The change of Coulomb Failure Stress has reached 0.1 MPa, which exceeded its critical value and activated the fault. The relatively long-time interval between the stimulation and the induced earthquake (i.e., 40 days apart) was attributed to the low permeability and geomechanics property from the injection layer to the fault. On the other hand, the subsequent Mw 4.1 event was triggered by the direct connection between the hydraulic fractures, natural fractures and the fault. In this case, the pore pressure variation along the nearby fault reached as high as 0.15 MPa. Results also showed that the Basement part of the fault tends to stabilize after releasing its energy of Mw 3.9 event. Sensitivity analysis has suggested that the faults were susceptible to the proximity between the fractures and the faults, the low permeability of injection layer and the low angle of fault orientation with respect to the maximum horizontal stress.
Infill drilling is a common technique to further develop the unstimulated region in-between parent wells for shale oil reservoirs. However, the potential of infill drilling to improve oil recovery depends heavily on the depletion-induced stress evolution at the selected infill locations. This work aims to model the spatial-temporal evolution of stress field for shale oil reservoirs in the Permian Basin and proposes the best timings for infill drilling to maximize the shale oil production. Based on history matching of an actual well, two types of fracture networks - with and without natural fractures (NFs) were generated for future production forecast. Our three-dimensional coupled geomechanics and compositional simulator with embedded discrete fracture model (EDFM) was used to simulate the pressure and stress redistribution associated with depletion in a highly fractured reservoir. A loosely coupled procedure is applied between fluid flow and geomechanics modeling to speed up the computation process while guaranteeing the simulation accuracy. The time window was determined by monitoring the orientation change of local maximum horizontal stress at the infill region, and the right timings for infill drilling were suggested accordingly. Field application in Permian basin indicates that the degree of stress reorientation at the infill region is closely related to the drainage area created by the complex fracture networks. When only hydraulic fractures present, the stress reversal in-between parent wells occurs after 0.8 year of production and gradually returns back to the original direction after 5 years; the critical time to perform infill drilling is recommended as before 0.8 year or after 5 years to ensure the child fractures propagating towards undepleted areas. When natural and hydraulic factures coexist, a similar phenomenon of stress reorientation is observed; the right timing for infill drilling in this case has been widened to before 1 year and after 3 years considering the higher conductivity introduced by complex natural fractures. Sensitivity analysis indicates that a smaller well distance and a higher bottomhole pressure will both help alleviate the stress reversal at the infill region, whereas a larger cluster spacing will narrow the available time window of infill drilling. The time-varying stress state at the infill region of shale oil reservoirs with complex fracture networks has been fully illustrated by our coupled geomechanics and multiphase compositional simulator. Based on the entire picture of stress reorientation process, this work suggests the best timings for infill drilling at the desired locations, which will significantly improve hydraulic fracturing performance and oil recovery in the Permian basin.
Iuliano, Alberto (Pan American Energy) | Gómez, Javier E. (Pan American Energy) | Martínez, Christian R. (Pan American Energy) | Alonso, Laura C. (Pan American Energy) | Kazempour, Mahdi (Nalco Champion, an Ecolab Company) | Kiani, Mojtaba (Nalco Champion, an Ecolab Company) | Alzate, Daniela (Nalco Champion, an Ecolab Company) | Singh, Praveen (BP) | Jerauld, Gary (BP)
The interplay among reservoir heterogeneities, structural complexities and unfavorable mobility ratios are usually responsible for premature water breakthrough in brown fields across the world. Recently, a deep conformance control technology, known as Thermally Activated Particle (TAP), has been successful in addressing this challenge. Limited intervention and lower deployment cost make it very attractive for mature waterflooded fields.
Cerro Dragón is a giant field located in San Jorge Gulf basin with multi-layered channel deposits. Presence of highly conductive channels and unfavorable mobility ratios have severely impacted the sweep efficiency, resulting in low oil recovery and high water production. Building on the learnings from the previous pilots, TAP has been recently deployed at a segment scale in one of the blocks of Cerro Dragón field. This paper shares the technical details behind the screening, designing and the deployment of TAP technology.
After initial screening of multiple candidates, a reservoir segment has been selected for TAP implementation. Inter well tracer data with comprehensive injection/production data analysis identified the communicating wells and thief zones volumes were then estimated around each injector. The estimated thief zones volumes were also confirmed by volumetric calculation. Thermal modeling and numerical simulation were utilized using a representative and history matched model to finalize the size, concentration and the proper activation of injected TAP molecules.
Subsequently, in early 2018, nearly 360 metric tons of TAP was safely deployed into six target injectors. This campaign met all design guidelines, all planned surveillance data was acquired, and the project was executed on time and on budget. Post deployment, frequent sampling at offset producers was performed confirming no breakthrough of un-activated polymeric particles. Oil rates and WOR trends are currently being monitored, as part of the longer-term surveillance plan, to quantify incremental benefits from TAP EOR technology.
Previous 2011 implementation and positive results in other segments of the field were an important input and they are also described in this paper.
The results of this treatment will provide very helpful guidelines that can be used in any brown fields to improve the efficiency of waterflooding especially in highly heterogeneous reservoirs with low waterflooding performance.
Li, Yingcheng (Sinopec Shanghai Research Institute of Petrochemical Technology) | Zhang, Weidong (Sinopec Shanghai Research Institute of Petrochemical Technology) | Shen, Zhiqin (Sinopec Shanghai Research Institute of Petrochemical Technology) | Jin, Jun (Sinopec Shanghai Research Institute of Petrochemical Technology) | Su, Zhiqing (Sinopec Shanghai Research Institute of Petrochemical Technology) | Yao, Feng (Sinopec Jiangsu Oil Field Company) | Yu, Xiaoling (Sinopec Jiangsu Oil Field Company) | Bao, Xinning (Sinopec Shanghai Research Institute of Petrochemical Technology) | He, Xiujuan (Sinopec Shanghai Research Institute of Petrochemical Technology) | Wu, Xinyue (Sinopec Shanghai Research Institute of Petrochemical Technology) | Zhang, Hui (Sinopec Shanghai Research Institute of Petrochemical Technology) | Sha, Ou (Sinopec Shanghai Research Institute of Petrochemical Technology)
The first pilot test of surfactant-polymer (SP) flood in the world with mixtures of anionic-cationic surfactants (S a/c) was carried out for a high temperature low permeability sandstone reservoir with high content of clay to demonstrate the potential of this novel technique to improve oil recovery. Low critical micelle concentrations (CMC) of 2.78 10 6 mol/L, ultralow interfacial tension (IFT) of 10 3 to 10 4 mN/m when surfactant concentrations were above 0.025 wt%, and lower phase microemulsion with high oil solubilization of 22, as well as 55.45 % oil washing rate were obtained by using S a/c . The adsorption inhibitor (AI) was adopted to reduce the adsorption because of the high clay contained in the natural core. Dynamic adsorption was about 0.30 mg/g with addition of AI, as well as IFT kept almost unchanged before and after adsorption. In order to reduce the injection pressure and improve the mobility ratio in the low permeability reservoir, low molecular weight polyacrylamide was adopted.