bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential Pressure Cone Meter as Meter Solution in FPSO's Facilities
Authors: Simatupang Ahmad Marzuki , Lalamentik Ruben
Published: October 2017

Demanding of oil & gas more increasing every year. However domestic production in Indonesia could not cover the demand, this phenomena resulting the deficit of oil & gas domestic stocks. Therefore, searching the new oil & gas sources shifting from onshore to the offshore and also deep water. FPSO development become the one important things to support exploration activities. One of the obstacles when design the production facilities in FPSO is limitation of space. All process equipment and instrument must be suitable with vessel space. Almost process instrument mainly in flow meter require upstream and downstream length to guarantee the accuracy of measurements.

In this paper will discuss about DP cone meter performance in support metering system in FPSO facilities. DP cone with size 2" and 6" will be tested. The beta ratio used in the testing are 0.45 and 0.75. The testing goals regarding the coefficient of discharge (Cd) curve performance doing in standard test and non standard test. In standard testing, each size of DP Cone meter connected with straight pipeline with 36D upstream length and 19D downstream length without flow disturbance element pipeline. Dp cone meter with size 2" tested with fluid which has Reynolds number 18,000 to 152,000 Re, and also Dp cone with size 6" tested with fluid which has Reynolds number 61,800 to 715,000 Re. In non standard testing, Dp cone meter directs connected with out of plane 90 degree elbow without requirement installation length in upstream and downstream and half of moon orifice plate with 3D upstream length and 5D downstream length. Maximum fluid Reynold number in the testing are 148,000 to 556,000 Re.

The results of testing showing that coefficient of discharge (Cd) Dp cone in standard testing and non standard testing do not change significantly. The curve showing good linearity and good performance. It verifies that Dp cone meter has resistance to swirl effect and poor flow profile. So, this flow meter more suitable with limitation space installation as FPSO
Remanufacturing Abandoned Tubing Based on Self-Propagating High Temperature Synthesis, Its Progress and Field Application Summary
Authors: Qiang Chen , Tao Li , Shouzhi Huang , Weiye Han , Qiang Sun
Published: October 2017

Cost reduction has been a strong tendency in the petroleum industry recently, annually millions of tons tubing is abandoned in China, leading to a huge resource waste. Based on self- propagating high temperature synthesis, abandoned tubing could be remanufactured functionally equivalent and visually indistinguishable compared to a new one, its field application has been launched in the oilfields and significant economic benefits was secured.

This paper presented three parts, first the three-dimensional finite element model was employed to study the maximum stress and residual strength of abandoned tubing corresponding to its wearing depth, failure criterion for abandoned tubing was established; second the alumina ceramic layer was prepared at the inner-wall surface of abandoned tubing based on self-propagating high temperature synthesis and the ceramic-lined composite tubing was obtained, the microstructure, corrosion resistance, mechanical properties and bonding capacity of the remanufactured tubing were evaluated, and finally the field operation of remanufactured tubing in harsh downhole environment was summarized.

The results indicated that the abandoned tubing must meet the requirement of certain criteria before being subjected to remanufacturing technique, that is 1.5mm for the J55 tubing and 2.8mm for the N80 tubing respectively; the bonding force between the steel pipe and alumina ceramic layer was more than 30MPa, the maximum impact energy was 73J, the maximum bending radius was 11m, making the remanufactured tubing capable of working in the harsh downhole environment, field application demonstrated its values, the popularization of remanufactured tubing in the oilfield is taking place.

This paper contributes to better understand the remanufacturing engineering in the perspective of petroleum industry, through the pioneering example and profound insights we are able to explore new horizons and yield more benefits to the long term healthy development of petroleum equipment.
Successful Re-Fracturing Application Using Temporary Gelled Isolation System in a Vertical Well in China
Authors: Wheeler Richard , Mayor J. , Williams V. , Kotov S. , McDonald T. , Guo X. , Zhao Z.
Published: October 2017

To maximize return on investment, many operators choose to re-fracture existing wells as an economic alternative to drilling new wells. While it may improve ultimate recovery, re-fracturing of wells with multiple producing zones can be challenging. Several techniques are available in the market place; each having its own limitations and benefits. The technology discussed in this paper, already implemented in the Western Hemisphere, uses a guar-based gelled fluid for temporary zonal isolation in the annulus. The need for a cost-effective solution for re-fracturing, without using a packer or other downhole isolation tool was identified in the Changqing oilfield in China. The objective was to prove the concept of using a gelled annular isolation technology for re-fracturing in this oilfield for applicability in the Asia Pacific region.

Two candidate wells were selected for re-fracturing based on previously completed methodologies and observed production declines. A two stage vertical well was selected for proof of concept. The original completion used a 5 ½-in. casing, applying multi-stage sand jetting fracturing. The application of the gelled polymer system for re-fracturing utilized the 5 ½-in. casing as an outer tubing and implemented a 3 ½-in. inner string to create an annular space for isolation. The gelled fluid was pumped into the annular space between the inner tubing string and the original casing to isolate existing perforations in the two stages. After the re-fracturing treatment was completed, the gel was broken down and the inner string removed.

Before the job was pumped, laboratory testing and simulation concluded that the gelled fluid would be placed within the pump time of the job and hold for the expected time frame of the fracturing operations. This testing provided detailed operational guidelines on placement time, pump rate, fluid shear rate at bottom hole temperature within the constraints of the wellbore architecture before committing to pump the job. The fluid was successfully placed and maintained isolation during fracturing stages. The inner string was removed from the hole following the breaking of the isolation fluid.

The novelty of this work included the application of using a guar-based gelled fluid as a temporary annular isolation pill in a re-fracturing application in China. In addition, this work proved that an inner completion string could also be temporary and therefore removed after the job was completed to ensure that maximum access to the reservoir was achieved. Finally, this is the first cost effective and simple re-fracturing methodology introduced to this area of the Asia Pacific region.
A Comprehensive Preparation Study for Microbial Nutrient Injection of Microbial Enhanced Oil Recovery: Reservoir Screening and Laboratory Analysis – Case Study Bentayan Field
Authors: Astuti D. I. , Ariadji T. , Aditiawati P. , Purwasena I. A. , Persada G. P. , Ananggadipa A. A. , Dewi U. R. , Khendarsyah D. D. , Rizki R. , Abqory M. H. , Ardianto R. N.
Published: October 2017

This paper demonstrates a comprehensive preparation study of field injection microbial nutrient starting from a quite extensive screening to select a field and wells, followed by a series of laboratory experiment seeking an optimum nutrient for the in-situ microbes through some oil properties examinations after giving the treatment. The laboratory examines many combination of nutrient to formulate an optimum nutrient, and compares oil sample compositions before and after treating at the optimum nutrient. The general screening evaluates field candidates based on the remaining oil in place, average porosity and average permeability for many fields in Indonesia. Having the field candidate is then followed by an Enhanced Oil Recovery screening that is a combination of Aladasani and Bryant methods. Hence, Bentayan Field is chosen and two wells were selected BN-38 and BN-81. We are confident that this field is possibly unfavorable for most EOR methods other than the MEOR. The laboratory experiment observed total bacteria number during the incubation period that was conducted every 7 days with method of Total Plate Count (TPC) on Nutrient Agar (NA) medium for aerobe facultative bacteria and Reinforced Clostridial Medium (RCM) for anaerobe bacteria. The results can be summarized and concluded that the optimum nutrient composition consists of molasses, nitrogen salts of (NH4)2PO4, and phosphate salt of NPK for BN-38 well is different from the one for BN-81 well, especially, the concentration of molasses. The oil composition after the treatment observed by GC/MS, clearly indicates becoming a much lighter composition then the previous to the extent that the heptane plus is degraded up to more than 30%. This irreversible mechanisms consequence to the viscosity reduction of up to 43.68% and 47.83% for BN-38 and BN-81, respectively. In addition, the imbibition experiment using synthetic core samples yield results of ultimate recovery factor of 56% at an optimum soaking time of 7 days for BN-81. Finally, a schematic diagram of field implementation the injection is presented that is much simpler than the microbial injection since does not need a cultivation tank at the surface.
Retention of Silica Nanoparticles in Limestone Porous Media
Authors: Al-Anssari Sarmad , Nwidee Lezorgia. N. , Ali Muhammad , Sangwai Jitendra S. , Wang Shaobin , Barifcani Ahmed , Iglauer Stefan
Published: October 2017

Nanofluids (dispersion of nanoparticles in a base fluid) have been suggested as promising agents in subsurface industries including enhanced oil recovery. Nanoparticles can easily pass through small pore throats in reservoirs formations; however, physicochemical interactions between nanoparticles and between nanoparticles and rocks can cause a significant retention of nanoparticles. This study investigated the transport, attach, and retention of silica nanoparticles in core plugs.

The hydrophilic silica nanoparticles were injected into limestone core as nanofluid of different nanoparticles size (5 nm, and 20 nm), concentration (0.005 – 0.1 wt% SiO2), and base fluid salinity (0 – 3 wt% NaCl) at different temperatures (23, and 50 °C). Deposition and transport of nanoparticles were measured via nanoparticle concentration of effluent fluid, and energy distractive spectroscopy (EDS) measurement on the limestone core.

It was found that silica nanoparticles dispersed in brine (NaCl) solutions are increasingly retained in limestone core as the solution ionic strength increases. On the other hand, less significant retention was measured when the nanoparticles were dispersed in DI water. The EDS measurements also reported the same trend of increased nanoparticles retention with salinity due to larger aggregates that result from the screening effect of the electrolyte on repulsive forces between nanoparticles. Thus, the observed change in surface wettability from oil to water-wet and the increase in oil production that reported in many core flooding laboratory studies are mainly related to the high adsorption rate of hydrophilic silica nanoparticles on carbonate surfaces.
Improve Production in Unconventional Oil Wells Using Artificial Sump Pumping System
Authors: Elmahbes Reda , Quintero Regulo
Published: October 2017

Unconventional oil wells represent a combination of challenges to electrical submersible pump (ESP) systems and can limit the production potential for those types of wells. Unconventional wells with steep decline curves and high amounts of free gas challenge the operating envelop of current ESP systems to economically and reliably produce these wells. The challenges that unconventional wells present for all forms of artificial lift forms are: (a) highly deviated wellbore; (b) high gas-to-oil ratio (GOR); (c) gas slugs; and (d) tight casing. When a large amount of free gas is present in the production fluid, the gas enters the ESP pumps and drastically affects its performance. In many cases the gas can lock the pump, leading to a production cut. This paper discusses a case history for an unconventional field where traditional ESP methods were used as the primary form of lift. The challenges in using this form of lift to economically produce from those wells are also discussed.

The use ofan artificial sump pumping system in unconventional oil wells with steep decline curve and high amount of free gas has a proven record of operating reliably and economically under unconventional wells challenges. Artificial sump pumping systems are configured and designed to fit inside 7-in. casing and bigger to tight casing sizesof 5½ in.through the use of slim-line ESP systems. The artificial sump pumping system uses an inverted shroud to naturally separate gas and block it from entering the pump. This blocking actionprevents the pump from experiencing gas lock due to unpredicted gas slugs. In addition, the system is equipped with a recirculation system to continue cooling the motor during gas slugs, enabling the ESP to continue producing efficiently during slug events. Moreover, a capillary tube could be installed with the system to enhance system run life for wells where corrosion and scale are issues.

This paper presents a comparison between the use of conventional ESP methods and artificial sump systems in unconventional, conventional, and mature fields where free gas and gas slugs are a challenge. The results shows how an artificial sump system improves production from those wells and how it significantly improves ESP run life operating under unconventional challenges. In addition, the benefit of using this system for protecting the motor lead extension during installation especially for deviated well and wells with high DLS. This paper discusses how the system reduced the number of failures and enhanced the run life for wells where corrosion and scale-related failures are an issue.
Fueling Our Future with Gas through End-to-End Integrated Optimisation of LNG Supplying Gas Fields
Authors: Chuah S. M. , Khor Y. Y. , Borhan N. A. , Baghdadi F.. , Adillah B. J.
Published: October 2017

In a complex offshore gas network covering both green and mature fields' production to LNG plants, end-to-end integration is essential in building a portfolio that can maintain output. Often in the course of identifying conceptual development opportunities by individual field, this aspect isoverlooked in the broader context of regional optimization. To provide assurance of production sustainability to meet commercial agreement, it is imperative to formulate a development plan that integrates subsurface and surface elements to accurately quantify the remaining reserves and thus the value of the asset. As such, this paper will focus on the methodology of formulating this optimized development plan to incorporate subsurface and surface network modeling and demonstrate the importance of this system for excellent asset management and future development.

A series of reservoir evaluations has been performed on a simple one-dimensional model and three-dimensional model depicting the gas reservoir performance. The analysis is further enhanced by using subsurface and surface production network modeling. The key advantages of this workflow compared to the conventional field development plan (FDP) approach is that the field capacity is derived based on pressure interface and existing production constraints to capture any backpressure effects for anyinfill drilling or upgrading projects.

In this field example, the integrated network model has resulted in a simpler yet more reliable technical proposal where synergistic opportunities and the associated potential production challenges can be identified.Higher level goals on production attainment and cost avoidance can be achieved through circumventing the potential production hiccups for new development. A detailed analysis workflow using real time data will be discussed as part of technical assurance.The key benefits include full field optimization and opportunities identification,and generation ofa representative business case in a timely manner to meet the demands of managing a dynamic gas system.
Closed Loop Speed Control System of ESPCP with Capillary Tube
Authors: Zhu Shijia , Hao Zhongxian , Wang Quanbin , Zhang Lixin
Published: October 2017

The ESPCP is a new rodless artificial lift, which completely gets rid of rod tubing wearing problems. Because of the higher efficiency of the system, the advantage of energy saving makes the new system used more and more widely in low production wells in CNPC. However, the working condition of system at the bottom of the well is hard to monitor. The pump and the motor are in danger of burning out when the dynamic liquid level is lower than the inlet.

In this paper, we introduce a closed loop control system with capillary tube to solve these problems. The system can monitor the pressure at the bottom of the well, and calculate the dynamic liquid level using downhole pressure and wellhead casing pressure. The system can adjust the speed of the motor according to the dynamic liquid level. In this way, it achieves the closed loop speed control of the motor. The pressure measurement cylinder was located above the pump preventing sand burial. The cylinder and the tube were filled with nitrogen, so the pressure was transmitted through a capillary tube to the sensor on the ground.

We have tested the capillary tube measurement system in the lab, the results of the experiments showed that the error of the measured pressure value was less than 5%. In this design, there is no semi-conductor device at the bottom of the well. So the measurement no longer suffered from the temperature drift of the sensors and the expensive price of high temperature resistance electronic devices. We have used this measurement system with ESPCP in Jilin and Jidong oil field in two wells. The results of the field experiments showed that the system can monitor the downhole pressure continually and it has been running for 4 months. Moreover, we could get two key parameters, downhole pressure and dynamic liquid level, by using this measurement system. It would be helpful for further system failure diagnosis.

The capillary tube downhole pressure measurement system was a cost-saving and stable system. It achieved the closed loop control and prevented the evacuation problem in low production wells. Also it makes contribution to the popularization of Electronic Submersible Progressing Cavity Pump (ESPCP). This paper will present the details of this design and experiments.
The Study and Application of a Electric Intelligent Well Completion System with Electrically Driven Inflow Control Device and Long-Term Monitoring
Authors: Liao Chenglong , Zhang Weiping , Huang Peng , Zhang Guowen , Qian Jie , Shen Zejun , Pei Xiaohan
Published: October 2017

Intelligent well systems are useful in controlling multiple zones, managing water, reduceing well interventions, and increasing ultimate recovery especially for the high water cut well with multiple zones. The traditional hydraulic intelligent well systems are very complex, and high cost particularly in the current period of low oil prices. In this paper, we introduce a cable electric intelligent well completion system(EIWS), which is much convenient and low cost.

The system includes electrically driven inflow control devices(EDICD) connected to a ground control device through a single tubing-encased conductor cable, crossing packer, and remote controller. The EDICD consists of downhole valve, control circuit, temperature sensor, and pressure sensor, which can realize the inflow control and monitoring together. Multiple EDICD can be used to adjust production performance for multiple zones independently. The valve opening degree of each EDICD can be adjusted in no-step. The power supply and real-time signal transmission are achieved by the single conductor cable. The ground control device provides precision control of downhole valves and collection of monitoring data. The operators can remotely control and monitor the system from anywhere by the remote controller, which features an intuitive interface showing the valve opening degree and monitoring data.

The applications of the EIWS were carried out in Tuha oilfield for field trials. The EIWS was installed in conjunction with a rod pump during the workover of an existing completion. The maximum depth of well is more than 3000 meters. The results show that the EIWS is convenient and reliable. The production performance of the zone with high water cut can be effectively adjusted. Meanwhile, the change trends of temperature and pressure for each zone are easily observed.

The long-term monitoring and real-time control are useful for the optimization of well production performance with higher efficiency. Moreover, the reduction of well interventions can save cost. This paper will illustrate the key learnings based on the field trials.
Modelling Trapped Gas Expansion in Water-Drive Reservoirs
Authors: Babadimas J. M.
Published: October 2017

Imbibition only relative permeability is commonly used to model water influx in water-drive gas reservoirs, however an aquifer is rarely strong enough to maintain constant pressure support. Continued pressure depletion in the part of the reservoir swept with watercauses expansion and remobilisation of trapped gas behind the waterfront. This paper presents a reservoir simulation study on modelling the expansion and remobilisation of trapped gas due to pressure depletion as secondary drainage flow using relative permeability hysteresis.

Previous studies in literature on relative permeability show the secondary drainage curve during blowdown is below the primary imbibition curve. This is based on field cases and core experimental studies, which establish the existence of a gas remobilisation threshold above residual saturation to reconnect the gas phase. Commonly used hysteresis models by Killough (1976) and Carlson (1981) are unable to model secondary drainage flow below the primary imbibition curve. The ODD3P hysteresis model developed by Hustad et al. (2010) was identified as the most appropriate method to model trapped gas expansion as secondary drainage flow below the imbibition curve. A reservoir simulation study was performed using the ODD3P hysteresis model to test scenarios which model trapped gas remobilisation as secondary drainage flow during pressure blowdown after waterflooding.

The conclusion of this study is that the standard formalisms used to model relative permeability hysteresis (Killough, Carlson) should not be used to model trapped gas remobilisation due to blowdown as they do not incorporate a gas remobilisation threshold and a secondary drainage curve underlying the primary imbibition curve. By assuming no mobility threshold above residual gas saturation, the total recovery of residual gas will be overestimated. Instead, by adopting the ODD3P hysteresis model, gas production will be lower and water production higher due to the correct use of secondary-drainage relative permeability curves in a gas reservoir invaded by water. This will lead to a significant improvement in results from reservoir simulation and the subsequentevaluation of trapped gas recovery.

The expansion and remobilisation of residual or trapped gas saturations has a major impact on the prediction and/or matching of production and pressure response from a reservoir. This study intends to understand these impacts and serve as a preliminary guideline in modelling trapped gas expansion and remobilisation as secondary drainage flow, which is applicable to many water-drive gas reservoirs.
Multiple Stage Vane Pump, a New Production Technology Used in Thermal Recovery Well
Authors: Quanbin Wang , Lixin Zhang , Shijia Zhu , Hongmei Huang , Tong Guo , Yongxin Li
Published: October 2017

China has a large quantity of heavy oil reservoir and many steam flooding wells and steam soaking wells. At present, normal artificial lift forms cannot meet the requirements for both high temperature lift and efficient lift. The traditional vane pump is a positive displacement pump which features its good high-temperature resistant performance and stable flow characteristics. Based on these features, the new multiple-stage vane pump (MVP) was designed. In the MVP, the flow direction was changed to the axial direction for fitting the slim wellbore; two or three stages were assembled in series connection for increasing the pumping pressure. In the laboratory, the comprehensive experiment workbench was used to test the relationship between pumping pressure, flow rate and other hydraulic parameters. The results show that MVP has smaller operation torque, high volumetric efficiency and high system efficiency. The artificial lift system of MVP uses conventional drive head as the energy source and sucker rod to transfer the energy downwards. The transmission system is specially designed for the MVP system, which can be used for power transmission, sand control and steam injection. It can realize the functions for both production and steam injection, which means that the production tubing and MVP are not pulled out in steam injection periods. The vane pump had been deployed in eight wells, two of them with steam injection valve. Compared with the beam pumping unit with the similar liquid-producing capacity, the energy consumption for the vane pump is about 30 percent lower.
Coalbed Methane Development in China: Engineering Challenges and Opportunities
Authors: Li Hangyu , Lau Hon Chung , Huang Shan
Published: October 2017

Commercial development of coalbed methane (CBM) in China has lasted for a decade. However, in 2015 annual CBM production in China was less than 5 Bcm and lagged far behind those in US (35 Bcm) and Australia (18 Bcm). In this paper, we review the published literature to determine the engineering challenges and opportunities of CBM production in China. Our review has identified seven major engineering challenges to CBM development in China. They are low cleat permeability and underpressured formation pressure of high-rank coals, ductility of coal seams, suboptimal fracturing fluids, formation damage during drilling, borehole instability in horizontal wells, frequent pump failures during production, and inadequate produced water treatment methods.

Each of these challenges provides an opportunity for improvement. We propose a refocus on low-rank coals which have higher permeability. Other opportunities include development of better hydraulic fracturing fluids, non-formation damaging drilling fluids, use of geomechanics to understand borehole instability, optimization of the artificial lift methods and more robust and environmentally friendly produced water treatment methods.
Study on Non-Contact Connection Separated Layer Production Technology and Its Application Test
Authors: Tong Guo , Xiaohan Pei , Yafeng Ju , Fuwei Bi , Quansheng Zhang , Qinghai Yang
Published: October 2017

Separated layer production is an effective means to mitigate inter-layer problems, minimize invalid water circulation and improve oilfield production efficiency. A non-contact connection separated layer production technology is developed in this paper to realize the automatic monitoring and control of production wells.

By developing a downhole production parameter monitoring and CPU management system, acquisition of downhole pressure, flow and temperature data, control of flow control valve opening, and saving of historical test and adjustment data into downhole system can be realized. A downhole communication sub is used for signal transfer. The ground and downhole communication sub communicate with each other via power line carrier, while the downhole communication sub makes wireless communication with the downhole automatic control system. Downhole charging from the ground is realized by utilizing the non-contract charging type power supply system.

An oil well test study is carried out based on this technology. The maximum temperature of the test well is 82°C, and the water cut is 96.8%. With successful downhole non-contact connection, stable and reliable data transmission at a rate of 9,600bps, and no data packet loss during communication, the test results have verified the feasibility of this technology and the realization of automatic monitoring and control of downhole working conditions. The downhole charging current is 7.4A, and the electric energy conversion efficiency is 31.4%. According to calculation results, the battery can be used for more than 20 times of automatic allocation of production flow. The adjustment interval is set at one month and the system can work continuously for more than one and a half years under this condition.

In this paper, the technical problems of non-contract charging and wireless data transmission in high temperature downhole environment are solved successfully, and a downhole separated layer production automatic control system is developed.
Novel Single-Trip Well Re-Stimulation Technology Enables Exact Treatment Placement While Significantly Decreasing Intervention Time
Authors: Castro Luis , Nasir Ehsaan , Wilbourn Maurice
Published: October 2017

This paper focuses on an operational review and lessons learned during the deployment of a novel straddle packer system in a refracturing application. The operation involved the deployment of an industry-first high-rate / high-pressure straddle packer to convey a propped refrac job to a previously producing well in a challenging application. The paper will also include relevant notes on operational time optimization derived from the field implementation as well as pre and post-treatment production information.

The paper describes details on overcoming the challenge of effectively isolating a single group of perforations among multiple producing zones of a wellbore in order to deliver a targeted stimulation treatment. The paper also discusses opportunities for improvement and learnings from this novel deployment. Finally the paper analyzes pressure and temperature data gathered during the treatment to assist in understanding job execution as well as post-treatment production information.

The novel stimulation technology enabled the operator to accurately place a propped refrac treatment at 20 bpm in a 200ft-long interval of previously producing perforations in a single run. The application reduced the operational time on location by 30% and reduced the number of runs required to complete the operation. Comparative production results will be shown as a measure of treatment effectiveness.

The paper contributes a novel insight to the intervention, stimulation, and refracturing industries by describing one of the first successful high-rate re-stimulation jobs using a straddle packer with open perforations above and below in a single trip. This insight is relevant as it highlights a cost-effective alternative for reviving existing wells at a fraction of the cost of a new drill, without the need to deploy numerous tools and fluids in multiple trips to achieve the zonal isolation as typically required in a re-stimulation treatment.
Application of Controlled-Influx Mud Cap Drilling Techniques in Exploiting the Marine Pre-Salt Carbonates in Santos Basin: Case Study
Authors: Yaqoob Tanveer , Bello Opeyemi , Oppelt Joachim
Published: October 2017

The pre-salt Coquina Carbonate beds in the Santos Basin are the prime focus of major oil producers in the region. In addition to the thick, unstable salt layers posing borehole stability and casing issues, a primary challenge in the appraisal of the faulted Coquina reserves is the handling of immense downhole losses in the weaker and occasionally fractured carbonate layers just below the salt strata. Although the bottomhole pressure limitations posed by conventional drilling have been eliminated by Managed Pressure Drilling attempts, the transition has also brought along a new set of technical challenges such as: Instability in wells while tripping and high fluid losses while restoring controlFailed attempts to regain control in loss zones by pumping lost circulation material/cement into fracturesDifficulty in zonal isolation, even with Managed Pressure CementingPore plugging and reservoir damage due to placement of cement as lost circulation materialWellbore depletion and differential sticking tendency during shut-in timeLimitations on the use of Positive Displacement Motors due to additional pressure fluctuations

The paper reviews the above challenges as planning and technological gaps suppressing the production prospects and investigates the application of Pressurized Mud Cap Drilling and Constant Bottomhole Pressure techniques with controlled Gas-Influx as an effective approach in mitigating the constraints by aligning the bottomhole pressure and the pore pressure. A case study for immense downhole losses in the reservoir interval has been presented. The results of feasibility analysis on reported case histories depict that circulating out the influxes while drilling with improved Surface Back Pressure systems minimizes losses, improves completion quality and reduces shut-in gaps.
Multiple Sand Control Solution to Adapt Well Productivity and Reserves by Using Mahakam Sand Control Tool Box
Authors: Styward B. , Muryanto B. , Wahyudhi F. , Wijaya R.
Published: October 2017

Multizone Single Trip Gravel Pack (MZ-STGP) Completion has been utilized as primary sand control system in Total E&P Indonesie. Over 250 wells have been successfully delivered since 2005 to maintain production plateau. Currently, the main challenge of this system is how to tackle number of marginal wells with higher geological uncertainties.

In order to ensure well economy, several completion systems need to be prepared as an alternative of the MZ-STGP in order to adapt with the actual well reserve. In fact, the alternative systems should have flexibility to replace MZ-STGP in a very short time to avoid rig standby. This paper will review the alternative solutions which provide both capability and flexibility to replace MZ-STGP in a very short time in order to unlock marginal reservoirs.

Thorough engineering design and progressive trial were performed since 2008 with the involvement of drilling contractors and transverse entities. The main objective of the trial is to implement the alternative system safely without hinder production performance and keep maintaining overall cost as minimum as possible. Mahakam Sand Control Tool Box (M-STOB) was then developed as group of alternative solutions to tackle the challenges mentioned above. It consists of four main solutions; Modular Gravel Pack System, Openhole Solution, Slim Gravel Pack and Thru Tubing Sand Control. Through these solutions, company is expected to have flexibility to adapt well architecture in a very short time based on actual well reserve.
Integrated 3D Pore Pressure Characterisation and Modeling: Methodology & Application in Sisi Nubi Field, Mahakam - Indonesia
Authors: Sukapradja Aldyth , Herdianto Roni , Clark Jesse , Adam Cepi , Ashari Untung , Saragih Baginda , Sitorus Rio , Giriansyah Bayu
Published: October 2017

Sisi-Nubi (SNB) is a gas field located 25 km offshore from the modern Mahakam delta with overpressure reservoirs being found typically in the Sisi Main Zone (SMZ) interval. SNB 3D seismic data indicates a velocity reversal in the SMZ interval, where the overpressure occurs. This velocity reversal has a relation with location of shelf break (distal area), where beyond shelf break the NTG value is sharply decreased.

In the Mahakam area, overpressure gas reservoirs are one of the main issues in terms of drilling hazards. This has been historically managed by integrating surrounding wells' pressure data to predict the pore pressure profile that would be expected in an upcoming well. In new areas or where pressure data is lacking, it is difficult to predict the PP which can result either in heavier than necessary well architectures or an increased risk of taking a kick.

An integrated pore pressure study has been carried out on the SNB field in order to provide three dimensional and spatially continuous pore pressure prediction using four different disciplines: sedimentology, reservoir geology, geophysics and geomechanics. The integrated pore pressure model over SNB is contained within a 3D geological model where the Eaton equation can be run using following datasets: sonic well data and sedimentological trend (Well Driven model), upscaled/resampled seismic interval velocity (seismic driven model) and hybrid method as compromise between two data sources involves using the seismic data as a soft trend for the extrapolated well data (hybrid model).

Based on the blind well test analysis, the hybrid methodology shows the best result in terms of precision and 3D distribution and allows a continuous prediction of pore pressures even where there is poor well control. However, the others two methodologies could be used as an alternative when the available data is limited.

This methodology gives a new approach with more integrated information in 3D pore pressure modeling that improved the classic pore pressure prediction in field Scale and/or basin scale. However, with the remaining uncertainty and discrepancy between the DT well scale velocity and the DT seismic velocity, and considering all detail well events important inputs (Gas evolution including long connection tests, kick, pressure test, HC bouyancy and other drilling events), collaboration with a strong 1D Pore Pressure synthesis will give a comprehensive result.
Pushing Boundaries through Simplification of Complex Carbonate Reservoir Modeling: Small Investment, Big Gains
Authors: Khor Y. Y. , Shrivastava S. K. , Borhan N. A. , Baghdadi F. , Motaei E. , Kadir Z. , Supaat S. F. , Anasir N. , Mithani A. H.
Published: October 2017

Material balance analysis, a primary engineering technique, is an indispensable tool used for understanding the production performance and field management of mature gas reservoirs. Compilation and analysis of pressure-production data together with acomprehensive geological understanding including in-place hydrocarbon volumes and inter-block communication are prerequisites for material balance analysis. Deviation of observed P/Z data away from a straight idealised line necessitates further study, as it often indicates erroneous estimates of participating in-place volumes, aquifer support or reserves. Lack of pressure measurements, questionable stratigraphic correlations and uncertainty surrounding aquifer propertiesor reservoir connectivity highlight the requirement for further evaluation.

The objective of study is to develop a multi-tank material balance modelfor a mature, heterogeneous and compartmentalised carbonate gas field. Ultimately, the model must besufficiently robust to elucidate the field's production mechanism and optimise future field-development opportunities.

In this field, the pressure production behavior can be divided into two trends, an early rapid declining pressure trend, followed by a stabilised gradual pressure decline. Owing to higher drawdown in the field's early production life and insufficient recharging, the quick pressure decline underestimates the initial in-place gas volume. This volume is not adequate to support the sustained gas production rates observed in later years. This observation required further detailed analysis regarding the nature of zonal communication across adjacent reservoir intervals to better understand the production behavior of development wells during the design of the material balance model.

This paper discusses a study in which material balance analysis is coupled with multi-field network models. Implementation of this workflow can be usedto drive subsurface developmentsin a relatively short period.
A Dynamic Hybrid Dual Porosity Model to Simulate the Waterflood-Induced Fractures in Low-Permeability Reservoir
Authors: Tianyi Fan , Shuhong Wu , Hua Li , Baohua Wang , Xiaobo Li
Published: October 2017

A new type of fracture which was caused by the waterflooding process in the low-permeability reservoirs has attracted the engineers’ great attention in China recently. This new type of fracture, named the waterflood-induced dynamic fracture, has a significant impact on the swept volume of water flooding and the distribution of remaining oil, and therefore, directly affects the reservoirs development. However, because of the special features of these fractures, such as the morphological changes, the time-varying permeability and vulnerable to the production performance, it is almost impossible to characterize them accurately in the normal reservoir simulation.

In order to describe the waterflood-induced dynamic fracture, a new model was established in this paper. By overlapping the dynamic fracture model and the psudo-tenser permeability model to the dual porosity model which consists of a set of disconnected matrix blocks and a network of connected fractures, a new dynamic hybrid dual porosity model was derived. Compared with the conventional dual porosity model, the dynamic hybrid dual porosity model allows the property of the fracture system to change with time, so that the above problems can be solved very well.

Through the numerical simulation of a typical low-permeability oilfield by using the established model, the evolution process of the waterflood-induced dynamic fracture including opening, extending and closing, and its impact on the development of the low-permeability reservoir were carefully studied. The simulation results show that the dynamic fracture grows continuously and slowly throughout the entire life of the oilfield development. And it has significantly narrowed the water flooding swept range, and reduced the vertical producing degree of water flooding to a certain extent, which is very consistent with the production performance data of this oilfield. Meanwhile, the precision accuracy of simulation result has been observably improved by using this new model, which indicates that the model can precisely depict the changes of the dynamic fracture both in its morphology and its properties.

Furthermore, the established dynamic hybrid dual porosity model could be used to elucidate the mechanism of the evolution of the waterflood-induced dynamic fracture and so forth. Therefore, it provides an important technical means for the study of the effective development and prompt adjustment of water injection policy of low-permeability reservoirs.
Study on Enhanced Oil Recovery of Water-Based Nanofluid with Functional Silica Nanoparticles
Authors: Yuyang Li , Caili Dai , Xinke Wang , Wenjiao Lv , Hongda Zhou , Mingwei Zhao
Published: October 2017

Although application of nanofluids in enhanced oil recovery has been reported, the dispersibility of nanoparticles in water is one of the most difficult problems to overcome in the process of application. In this research, (3-mercaptopropyl) trimethoxysilane and sodium p-styrene sulfonate were alternatively assembled on the surface of silica nanoparticles. Fourier transform infrared spectroscopy was used to identify the surface components of functional silica nanoparticles. Transmission electron microscopy was employed for observing the shape and the size of functional silica nanoparticles. The water-based nanofluid with functional silica nanoparticles was stable at pH 9. Particle size distribution of nanofluid (with a mean diameter of 20±8 nm) was investigated by dynamic light scattering. Imbibition tests of water-based nanofluid, alkaline aqueous solution (pH value equality with the water-based nanofluid) and brine into oil presaturated ultra-low permeability sandstone cores were completed. As expected, the oil recovery of the core immersed in nanofluid was significantly higher than cores immersed in alkaline water (pH 9) and 3 wt% NaCl solution. To reveal the mechanism responsible for enhanced oil recovery, contact angle measurements were performed on the oil-wet surface before and after treatment with the nanofluid. The results showed that the wettability of the oil-wet surface changed from oil-wet to water-wet after treatment with nanofluid. The crude oil displacement from anoil-wet glass surface innanofluid was also studied. The nanofluidexhibitedan excellent capability that makesoil displace from an oil-wet surface. These results aid our understanding of the role of the nanofluid in displacing crude oil from the rock. The essential results from our experiments showed that nanoparticles can be stably dispersed in water by surface-functionalized and nanofluid have more potential in enhanced oil recovery.
Implementation of a Drilling Microchip for Downhole Data Acquisition
Authors: Li Bodong , Gooneratne Chinthaka P , Badran Mohammed S , Shi Zhaorui
Published: October 2017

First and secondgeneration drilling microchipsare compared side by side on design architecture, system components, sensors, output signal, build materials etc. Temperature microchips were field tested in an on-shore well. From the 20 deployed microchips, 6 passed through the bit nozzles and survived the drilling process without causing any downtime to the operation. The data recorded by different microchips showed excellent consistency over the downhole part of the trip, from inside of the drill pipe up the annulus to the surface. This is the first time that a drilling microchip was successfully deployed while drilling, and a complete set of data recorded throughout the entire trip from drill pipe, to the annulus, all the way to the flow line and shale shaker. The consistent results from the microchip provide valuable information for a wide range of drilling activities.