Summary. The Hall plot was originally used to analyze water-injection wells. This paper demonstrates that the Hall plot can also be used to analyze injection of polymer solutions. In particular, it is possible to determine the in-situ and residual resistance factors of a polymer solution from the Hall plot. The analysis methods developed are used to examine two field injection tests and one hypothetical example. The analytical results are verified with a reservoir simulator. Introduction Polymer floods, micellar/polymer floods, and injectivity- or productivity-profile-modification treatments are the most common applications of polymer solutions. The interpretation of injection pressures and rates associated with polymer solution injection is important to the efficient application of the solutions. The Hall plot is a useful tool for evaluating performance of injection wells. The Hall plot was originally developed for single-phase, steady-state, radial flow of Newtonian liquids. Since the advent of polymer and micellar solutions for EOR, it has also been applied to the injection of these solutions. Moffitt and Menzie used the Hall plot to evaluate injection of polymer solutions but did not verify the validity of the Hall plot for this application. This paper verifies the validity of the Hall plot for evaluating polymer solution injection. Because of the complex nature of polymer solution flow through porous media, exact analytical solutions are generally not possible. However, some relatively simple approximate analytical solutions can be developed. To verify the analytical solutions for polymer solution injection, a two-phase, radial, numerical reservoir simulator was developed. The simulator is designed to consider the more important phenomena and effects that occur when polyacrylamide or polyacrylamide polymer solutions are injected into porous media. The simulator has the following characteristics: slightly compressible flow, two-phase flow, non-Newtonian rheology, adsorption/retention with permeability reduction, concentration effects, skin, and wellbore storage. It was used to history match two field injectivity data sets. Development of the Hall Plot The Hall plot was originally proposed to analyze the performance of waterflood injection wells. Hail simply used Darcy's law for single-phase, steady-state, Newtonian flow of a well centered in a circular reservoir:(1) Hall integrated both sides with respect to time to obtain (2) Separating the integral of Eq. 2, Hall then rearranged to obtain (3) The relation between surface and bottomhole pressures for steady-state vertical flow is given by (4) Hall substituted Eq. 4 into Eq. 3 to arrive at (5) Hall simply dropped the second term on the right side of Eq. 5 and plotted the integral of wellhead pressures with respect to time vs. cumulative injection, which came to be known as the "Hall plot." By plotting in this format, Hall observed that if an injection well was stimulated, the slope decreased, and if a well was damaged, the slope increased. While Hall's conclusions regarding changes in slope are valid, the second term on the right side of Eq. 5 is often not negligible in comparison with the other terms and therefore usually cannot be dropped. In industry applications, the Hall integrals dt and f frequently are used. The slopes calculated from these integrals should not be used for quantitative calculations unless a correction procedure is applied. Fig. 1 is a Hall plot based on the data for Well A, where the integral dt has been plotted vs. cumulative injection. Several changes in slope can be seen on the plot, but there has been no change in transmissibility or skin. The changes in slope are caused by changes in rate, which occur because the integraldt has been neglected. Fig. 2 is a Hall plot based on data for Well C. The three most common forms of the Hall integral have been plotted for the same data. For each integration method, the slopes of the curves are quite different. Injection data must be plotted in the form of Eq. 2 to make valid quantitative calculations; i.e., cumulative injection should be plotted vs. (Pwf-pe)dt. The slope of the Hall plot from Eq. 2 is then given by(6) Eq. 6 will not be appropriate when multiple fluid banks with significantly different properties exist in the reservoir. Advantages and Disadvantages The Hall plot is a steady-state analysis method, whereas falloff tests, injection tests, and type-curve analysis are transient methods. Transient pressure analysis methods determine the reservoir properties at essentially one point in time. The Hall plot is a continuous monitoring method; i.e., reservoir properties are measured over a period of weeks and months. The Hall plot, therefore, can help identify changes in injection characteristics that occur over an extended period. Hall's method has several advantages. Integrating the pressure data with the Hall integral [ (pwf-pe)dt] has a smoothing effect on the data. Data acquisition for the Hall plot is inexpensive because only the recording of cumulative injection and surface pressures is required. SPERE P. 41^

A novel means of mitigating steam channeling and premature steam breakthrough in steamdrives has been successfully applied in the West Coalinga Field, California. A unique polymer gel system, organically crosslinked in-situ, has shown the ability to divert steam from pre-existing steam channels thus, improving areal steam sweep efficiency. Small volumes of this specially designed polymer gel system (<500 bbls [<79.5 m3]) were injected in six steamdrive injection wells. The applied treatments required only a minor interruption to continuous steam injection and were performed without any interruption to project production. Analyses of treatment performances have shown positive results in less than one month. Sustained performance of the first treated injector lasted over six months. Others have continued five months without signs of significant degradation. In treating early steam. breakthrough cases, effective polymer gel placement has reduced casing effluent (steam) rates and casing pressures. Reduced casing pressure combined with increased pumping efficiency has resulted in oil production rate increases. By reducing the volume of live steam produced out of the casing, the project thermal efficiency has been improved through increased utilization of injected heat. Temperature observation well data have shown substantial reservoir temperature decreases two months after injecting the gel system. These data suggest a redistribution of reservoir heat thus, improved areal sweep.

Controlling steam conformance in the horizontal injectors of SAGD projects is widely accepted as being critical for commercial success. This work is focused on steam distribution in horizontal injectors in mobile, heavy oil (non-bitumen), thermal development projects. Steam Conformance can be achieved by tubing or liner deployed FCD's (flow control devices). Liner deployed FCD's have several advantages over tubing-deployed FCD's which includes: smaller tubulars, lower capital costs, reduced well interventions, and potentially reduced surveillance requirements. This paper provides an overview of a collaborative development methodology for liner-deployed FCD's in horizontal steam service between a service company and operator. This methodology included: Establishing functional, operational and dimensional basis of designComputational fluid dynamics (CFD) analysis of the FCD design and phase-split testing in the Horizontal Steam Injection Test Facility (HSITF)Design revisions based on CFD, HSITF and shift testing resultsField installations results based upon fiber optic, thermo-hydraulic, and mechanical analysis These FCD's were designed with sliding-sleeve technology to enable opening or closing of each device. Different specifications of electroless nickel (EN) coatings were also tested to determine the performance for scaling and corrosion resistance. Within 6 months, three versions of the FCD's were tested in the HSITF with accompanying CFD. For each version the shifting forces before and after ~6 weeks of steam injection were measured. Each generation was improved based on the data from the prior version. In December 2018, three FCD's were installed in a large bore horizontal steam injector in a tubing deployed completion for field qualification of the devices. This installation was the first step of a one-year field qualification test. The full test will involve multiple interventions to opening and closing the FCD's. A capillary tubing with fiber optic wrapped around the tubing and devices can confirm FCD openings or closings. The field qualification will also test the local operational capability to shift the FCD's. At the end of the field qualification, the flow devices will be retrieved for inspection and identification of further design improvements.

Demands on the petroleum industry are driving continual improvement of Health, Safety, and Environment (HSE) performance. It has become widely recognized that the deliberate and structured creation of HSE culture directly affects HSE performance. Developing HSE culture is a complex recipe that combines values, leadership, management systems and processes, behavioral and cognitive psychology, technology, equipment, and HSE expertise. This combination creates a culture or " way of working in the organization." There are many theoretical and practical papers on the creation and assessment of HSE culture. For a leader in Exploration and Production (E&P) operations, the distillation of this large body of knowledge into an appropriate course of action can be a daunting task. A generic HSE cultural maturity model is provided in this work. HSE culture is further defined in terms of cultural dimensions. To improve HSE performance, development of culture cannot be confined within an E&P operator's organization. Contractors, partners, service providers, and suppliers must also be included in the development of HSE culture. Guidance is provided to help the E&P practitioner work collaboratively with contractors to develop, sustain, and improve HSE culture and performance. Pragmatic examples are provided for diagnosing HSE culture. Introduction Petroleum industry stakeholders (e.g. communities, governments, shareholder, employees, and NGO's) are requiring ever improving HSE performance. Today, delivering world-class HSE and operational excellence performance cannot be realized through policies, management systems, processes, and technology alone. While the foregoing aspects are important prerequisites to establishing world-class HSE performance, more is needed. HSE culture is recognized today as one of the key ingredients to delivering world-class HSE performance in E&P operations as well as numerous other industries. [1–10] Quantitative relationships have been established between HSE culture and HSE performance based on workforce cultural surveys[10–12] as given in Table 1. In this example, high favorability based on a workforce survey is indicative of a mature HSE culture, which has a statistically significant relationship with lower incident rates. HSE culture must be consciously developed, monitored, and have continual improvement. This paper builds on the current body of work on HSE culture. Provision of methods and techniques for creating the enabling culture and mind-set required to sustain and maintain continual improvement of HSE results are given. Creating a strong HSE culture with E&P company employees only is not adequate to produce world-class HSE performance. Today, HSE performance and culture for E&P operations is measured on a total workforce basis. Contractors typically comprise a significant proportion of the workforce, which can be from 50% to 90% of the workforce. In addition to employees, the definition of workforce members includes contractors, service providers, and suppliers. These members are either dedicated, co-located, or take the majority of work directions from a specific E&P operation. One of the challenges the E&P operator faces is the integration of diverse cultures from the different organizations that comprise the workforce. Specific experience and recommendations are provided to address this challenge.

Steam conformance control in horizontal injectors is important for efficient reservoir heat management in heavy oil fields. Suboptimal conformance and non-uniform heating of the reservoir can substantially impact the economics of the field development, oil production response and result in non-uniform steam breakthrough. In order to achieve the required control, it is essential to have an appropriate well completion architecture and robust surveillance. Five fiber optic systems, each utilizing a unique steam conformance control completion configuration, have been installed in two horizontal steam injectors to help mature steam injection flow profiling and conformance control solutions. These fiber optic systems have utilized custom designed fiber optic bundles of multimode and single mode fibers, for distributed temperature sensing (DTS) and distributed acoustic sensing (DAS) respectively. Fiber optic systems were also installed in a steam injection test flow loop. All the optical fibers successfully acquired data in the wells and flow loop, measuring temperature and acoustic energy. A portfolio of algorithms and signal processing techniques were developed to interpret the DTS and DAS data for quantitative steam injection flow profiling. The heavily instrumented flow loop environment was utilized to characterize DTS and DAS response in a design of experiment matrix to improve the flow profiling algorithms. These algorithms are based on independent physical principles derived from multiphase flow, thermal hydraulic models, acoustic effects, large data array processing, and combinations of the foregoing methods for both transient and steady state steam flow. A high-confidence flow profile is computed based upon convergence of the algorithms. The flow profiling algorithm results were further validated utilizing a dozen short-offset, injector observation wells in the reservoir that confirmed steam movement near the injectors.